,transcriber's ,notes3 ,mathematical problems could not be represented as in the original as we cannot stack numbers4 ,the following rules were used3 ,parentheses added to groupings of numbers4 ,bracket and rt square roots4 #crt ,carets and curly brackets indicate a superscripted number1 letter or symbol4 #dc ,an underscore and curly brackets indicate a subscript4 ,h#b,o ,bold text is surrounded by equal signs and italic text is surrounded by underscores4 ,illustration3 ,the ,suna before the ,explosion4 ,illustration3 ,the ,torpedo4 ,illustration3 ,the ,suna after the ,explosion4 ,griffin ,co4 ,portsmouth4 ,w4,f4 ,mitchell del4 ,,torpedoes ,,and ,,torpedo ,,warfare3 ,,containing ,a ,,complete ,,and ,,concise ,,account ,,of ,,the ,,rise ,,and ,,progress ,,of ,,submarine ,,warfare2 ,,also ,a ,,detailed ,,description ,,of ,,all ,,matters ,,appertaining ,,thereto1 ,,including ,,the ,,latest ,,improvements4 ,,by ,c4 ,w4 ,,sleeman1 ,,esq41 ,,late ,,lieut4 ,r4,n41 ,,and ,,late ,,commander ,,imperial ,,ottoman ,,navy4 ,,with ,,fifty-,,seven ,,full-,,page ,,illustrations1 ,,diagrams1 ,,woodcuts1 c4 ,,portsmouth3 ,,griffin ,,co41 #b1 ,,the ,,hard1 7,publishers by ,appointment to ,h4,r4,h4 ,the ,duke of ,edinburgh47 ,,london ,,agents3 ,,simpkin1 ,,marshall1 ,,co4 #ahhj4 ,all ,rights reserved4 ,,preface4 ,,in the following pages the ,author has endeavoured to supply a want1 viz4 a comprehensive work on ,torpedo ,warfare1 brought down to the latest date4 ,the information has been obtained while practically engaged in torpedo work at home and abroad1 and from the study of the principal books which have already appeared on the subject1 and to the authors of which he would now beg to express his acknowledgments1 viz43 ,submarine ,warfare1 by ,lieut4-,commander ,barnes1 ,u4,s4,n42 ,notes on ,torpedoes1 by ,major ,stotherd1 ,r4,e42 ,art of ,war in ,europe1 by ,general ,delafield1 ,u4,s4,a42 ,life of ,fulton1 by ,c4 ,d4 ,colden2 ,torpedo ,war1 by ,r4 ,fulton2 ,armsmear1 by ,h4 ,barnard2 ,treatise on ,coast ,defence1 by ,colonel ,von ,scheliha2 ,professional ,papers of the ,royal ,engineers2 ,the ,engineering2 ,the ,engineer2 ,scientific ,american2 ,iron2 c41 c4 ,the ,author is also desirous of thanking the following gentlemen1 to whom he is indebted for much of the valuable information contained herein3-- ,messrs4 ,siemens ,brothers1 ,messrs4 ,thornycroft and ,co41 ,messrs4 ,yarrow and ,co41 ,captain ,c4 ,a4 ,mc,evoy1 #ah ,adam ,street1 ,w4,c41 ,mr4 ,l4 ,lay1 ,messrs4 ,j4 ,vavaseur and ,co4 ,,london1 #ahgi4 ,,contents4 ,,page ,preface iii ,,chapter ,i4 ,the early ,history of the ,torpedo--,remarks on the existing ,state of ,torpedo ,warfare #a ,,chapter ,,ii4 ,defensive ,torpedo ,warfare--,mechanical ,submarine ,mines--,mechanical ,fuzes--,mooring ,mechanical ,mines #ac ,,chapter ,,iii4 ,defensive ,torpedo ,warfare 7continued7--,electrical ,submarine ,mines--,electrical ,fuzes--,insulated ,electric ,cables--,electric ,cable ,joints--,junction ,boxes--,mooring ,electrical ,submarine ,mines #bg ,,chapter ,,iv4 ,defensive ,torpedo ,warfare 7continued7--,circuit ,closers--,firing by ,observation--,voltaic ,batteries--,electrical ,machines--,firing ,keys and ,shutter ,apparatus--,testing ,submarine ,mines--,clearing a ,passage through ,torpedo ,defences #fj ,,chapter ,v4 ,offensive ,torpedo ,warfare--,drifting ,torpedoes--,towing ,torpedoes--,locomotive ,torpedoes--,spar ,torpedoes--,general ,remarks on ,offensive ,torpedoes #aae ,,chapter ,,vi4 ,torpedo ,vessels and ,boats--,the ,uhlan--,the ,alarm--,the ,destroyer--,thornycroft's ,torpedo ,boats--,yarrow's ,torpedo ,boats--,schibau's ,torpedo ,boats--,herreshoff's ,torpedo ,boats--,torpedo ,boat ,attacks--,submarine ,boats #aeh ,,chapter ,,vii4 ,torpedo ,operations--,the ,crimean ,war 7#ahed-ef7--,the ,austro-,italian ,war 7#ahei7--,the ,american ,civil ,war 7#ahfa-fe7--,the ,paraguayan ,war 7#ahfd-fh7--,the ,austrian ,war 7#ahff7--,the ,franco-,german ,war 7#ahgj-ga7--,the ,russo-,turkish ,war 7#ahgg-gh7 #ahg ,,chapter ,,viii4 ,on ,explosives--,definitions--,experiments- -,gunpowder--,picric ,powder--,nitro-,glycerine--,dynamite--, gun-cotton--,fulminate of ,mercury--,dualin--,lithofracteur--,hors ley's ,powder--,torpedo ,explosive ,agents--,torpedo ,explosions #bjd ,,chapter ,,ix4 ,torpedo ,experiments--,chatham1 ,england1 #ahfe--;,austria--,carlscrona1 ,sweden1 #ahfh--,kiel1 ,prussia--,england1 #ahgd--;,copenhagen1 ,denmark1 #ahgd--;,carlscrona1 ,sweden1 #ahgd-ge--,portsmouth1 ,england1 #ahgd-ge--,pola1 ,austria1 #ahge--,portsmouth1 ,england1 #ahgf--;,experiments with ,countermines--,the ,medway1 ,england1 #ahgj--,stokes ,bay1 ,england1 #ahgc--;,carlscrona1 ,sweden1 #ahgd #bbj ,,chapter ,x4 ,the ,electric ,light--,the ,nordenfelt and ,hotchkiss ,torpedo ,guns--,diving #bci ,,chapter ,,xi4 ,electricity #bfe ,,appendix4 ,mc,evoy's ,single ,main ,systems #bhc ,siemens' ,universal ,galvanometer ,tables #bhg ,synopsis of the ,principal ,events that have occurred in connection with the ,history of the ,torpedo #bij ,index #big ,,list ,,of ,,plates4 ,,destruction ,,of ,,turkish ,,gunboat ,,suna 7,frontispiece74 ,i4 ,,fulton',s ,,torpedoes4 ,,ii4 ,,frame ,,torpedoes1 ,,buoyant ,,mechanical ,,mines4 ,,iii4 ,,singer',s ,,and ,,mcevoy',s ,,mechanical ,,mines4 ,,iv4 ,,extempore ,,mechanical ,,mine1 ,,mechanical ,,primers4 ,v4 ,,mechanical ,,fuzes4 ,,vi4 ,,form ,,of ,,case ,,of ,,submarine ,,mines4 ,,vii4 ,,electric ,,fuzes4 ,,viii4 ,,electric ,,cables1 ,,extempore ,,cable ,,joints4 ,,ix4 ,,permanent ,,joints ,,for ,,electric ,,cables4 ,x4 ,,junction ,,boxes1 ,,mechanical ,,turk',s ,,head4 ,,xi4 ,,moorings ,,for ,,submarine ,,mines4 ,,xii4 ,,steam ,,launch ,,for ,,mooring ,,submarine ,,mines4 ,,xiii4 ,,mathieson',s ,,circuit ,,closer4 ,,xiv4 ,,austrian ,,circuit ,,closer1 ,,mercury ,,circuit ,,closer4 ,,xv4 ,,mcevoy',s ,,magneto ,,electro ,,circuit ,,closer4 ,,xvi4 ,,russian ,,submarine ,,mine1 ,,firing ,,by ,,observation4 ,,xvii4 ,,apparatus ,,for ,,firing ,,by ,,observation4 ,,xviii4 ,,systems ,,of ,,defence ,,by ,,submarine ,,mines4 ,,xix4 ,,firing ,,batteries1 ,,testing ,,batteries4 ,,xx4 ,,firing ,,keys1 ,,shutter ,,apparatus4 ,,xxi4 ,,shutter ,,apparatus4 ,,xxii4 ,,galvanometers ,,for ,,testing4 ,,xxiii4 ,,siemens' ,,universal ,,galvanometer4 ,,xxiiia4 ,,ditto ,,ditto4 ,,xxiv4 ,,ditto ,,ditto4 ,,xxiva4 ,,ditto ,,ditto4 ,,xxv4 ,,shunt1 ,,commutator1 ,,rheostat4 ,,xxvi4 ,,wheatstone',s ,,bridge4 ,,xxvii4 ,,test ,,table1 ,,differential ,,galvanometer4 ,,xxviii4 ,,methods ,,of ,,testing--,,armstrong--,,austrian4 ,,xxix4 ,,drifting ,,torpedoes4 ,,xxx4 ,,harvey',s ,,towing ,,torpedo4 ,,xxxi4 ,,ditto ,,ditto4 ,,xxxii4 ,,systems ,,of ,,attack ,,with ,,harvey',s ,,sea ,,torpedo4 ,,xxxiii4 ,,ditto ,,ditto4 ,,xxxiv4 ,,ditto ,,ditto4 ,,xxxv4 ,,german ,,and ,,french ,,towing ,,torpedoes4 ,,xxxvi4 ,,whitehead',s ,,fish ,,torpedoes4 ,,xxxvii4 ,,thornycroft',s ,,boat ,,apparatus ,,for ,,fish ,,torpedoes4 ,,xxxviii4 ,,lay',s ,,locomotive ,,torpedo4 ,,xxxix4 ,,ditto ,,ditto4 ,,xl4 ,,ditto ,,ditto4 ,,xli4 ,,ditto ,,ditto4 ,,xlii4 ,,ditto ,,ditto4 ,,xliii4 ,,ditto ,,ditto4 ,,xliv4 ,,mcevoy',s ,,duplex ,,spar ,,torpedoes4 ,,xlv4 ,,the ,,alarm ,,torpedo ,,ship4 ,,xlvi4 ,,the ,,destroyer ,,torpedo ,,ship4 ,,xlvii4 ,,thornycroft',s ,,torpedo ,,boats4 ,,xlviii4 ,,ditto ,,ditto4 ,,xlix4 ,,yarrow',s ,,torpedo ,,boats4 ,l4 ,,ditto ,,ditto4 ,,li4 ,,russian ,,torpedo ,,boat1 ,,herreshoff',s ,,torpedo ,,boat4 ,,lii4 ,,submarine ,,mine ,,explosion4 ,,liii4 ,,ditto ,,ditto4 ,,liv4 ,,mcevoy',s ,,single ,,main ,,system4 ,illustration ,torpedoes and ,torpedo ,warfare4 ,,chapter ,i4 ,,the ,,early ,,history ,,of ,,the ,,torpedo4--,,remarks ,,on ,,the ,,existing ,,state ,,of ,,torpedo ,,warfare4 ,,the earliest record we have of the employment of an infernal machine at all resembling the torpedo of the present day1 was in #aehe at the siege of ,antwerp4 ,here by means of certain small vessels1 drifted down the stream1 in each of which was placed a magazine of gunpowder1 to be fired either by a trigger1 or a combination of levers and clockwork1 an ,italian engineer1 ,lambelli1 succeeded in demolishing a bridge that the enemy had formed over the ,scheldt4 ,so successful was this first attempt1 and so tremendous was the effect produced on the spectators1 by the explosion of one of these torpedoes1 that further investigation of this new mode of ,naval warfare was at once instituted4 ,but it was not until some two hundred years after that any real progress was effected1 though numerous attempts were made during this period1 to destroy vessels by means of sub-marine infernal machines4 ,it was owing to the fact1 that the condition which is now considered as essential in torpedo warfare1 viz41 that the charge must be submerged1 was then entirely ignored1 that so long a standstill occurred in this new art of making war4 ,captain ,bushnell1 the ,inventor of ,torpedoes4--,to ,captain ,david ,bushnell1 of ,connecticut1 in #agge1 is most certainly due the credit of inventing torpedoes1 or as he termed them submarine magazines4 ,for he first proved practically that a charge of gunpowder could be fired under water1 which is incontestably the essence of submarine warfare4 ,submarine ,boat4--,to ,captain ,bushnell is also due the credit of first devizing a submarine boat for the purpose of conveying his magazines to the bottom of hostile ships and there exploding them4 ,drifting ,torpedoes4--,another plan of his for destroying vessels1 was that of connecting two of his infernal machines together by means of a line1 and throwing them into the water1 allowing the current to carry them across the bows of the attacked ship4 ,mode of ,ignition4--,the ignition of his magazines was generally effected by means of clockwork1 which1 when set in motion1 would run for some time before exploding the machines1 thus enabling the operators to get clear of the explosion4 ,captain ,bushnell's few attempts to destroy our ships off the ,american coast in #aggf and #aggg1 with his submarine boat1 and his drifting torpedoes were all attended with failure1 a result generally experienced1 where new inventions are for the first time subjected to the test of actual service4 ,robert ,fulton4--,robert ,fulton1 an ,american1 following in his footsteps1 some twenty years after1 revived the subject of submarine warfare1 which during that interval seems to have been entirely forgotten4 ,a resident in ,france1 in #agig1 he is found during that year making various experiments on the ,seine with a machine which he had constructed1 and by which he designed to impart to carcasses of gunpowder a progressive motion under water1 to a certain point1 and there explode them4,a ,fulton's ,failures4--,though these first essays of his resulted in failure1 ,fulton thoroughly believed in the efficacy of his schemes1 and we find him1 during that and succeeding years1 vainly importunating the ,french and ,dutch ,governments1 to grant him aid and support in carrying out experiments with his new inventions1 whereby he might perfect them1 and thus ensure to whichever government acceded to his views1 the total destruction of their enemy's fleets4 ,bonaparte aids ,fulton4--,though holding out such favourable terms1 it was not until #ahjj1 when ,bonaparte became ,first ,consul1 that ,fulton's solicitations were successful1 and that money was granted him to carry out a series of experiments4 ,in the following year 7#ahja71 under ,bonaparte's immediate patronage1 ,fulton carried out various and numerous experiments in the harbour of ,brest1 principally with a submarine boat devised by him 7named the ,nautilus71 subsequently to his invention of submarine carcasses as a means of approaching a ship and fixing one of his infernal machines beneath her1 unbeknown to the crew of the attacked ship4 ,first ,vessel destroyed by ,torpedoes4--,in ,august1 #ahja1 ,fulton completely destroyed a small vessel in ,brest harbour by means of one of his submarine bombs1 then called by him for the first time1 torpedoes1 containing some twenty pounds of gunpowder4 ,this is the first vessel known to have been sunk by a submarine mine4 ,bonaparte's patronage withdrawn4--,notwithstanding the apparent success1 and enormous power of ,fulton's projects1 on account of a failure on his part to destroy one of the ,english ,channel fleet1 at the end of #ahja1 ,bonaparte at once withdrew his support and aid4 ,disgusted with this treatment1 and having been previously pressed by some of ,england's most influential men1 to bring his projects to that country1 so that the ,english might reap the benefit of his wonderful schemes1 ,fulton left ,france1 and arrived in ,london1 in ,may1 #ahjd4 ,pitt supports ,fulton4--,mr4 ,pitt1 then ,prime ,minister1 was much struck with ,fulton's various schemes of submarine warfare1 and after examining one of his infernal machines1 or torpedoes1 exclaimed1 that if introduced into practice1 it could not fail to annihilate all military marines4,b ,though having secured the approval of ,mr4 ,pitt1 and a few other members of the ,government1 he was quite unable to induce the ,english to accept his schemes in toto1 and at once employ them in the ,naval service4 ,twice ,fulton attempted to destroy ,french men-of-war1 lying in the harbour of ,boulogne1 by means of his drifting torpedoes1 but each time he failed1 owing as he then explained1 and which afterwards proved to be the case1 to the simple mistake of having made his machines specifically heavier than water1 thus preventing the current from carrying them under a vessel's bottom4 ,destruction of the ,dorothea4--,though in each of the above-mentioned attempts ,fulton succeeded in exploding his machines1 and though on the #aeth ,october1 #ahje1 in the presence of a numerous company of ,naval and other scientific men1 he completely demolished a stout brig1 the ,dorothea1 off ,walmer ,castle1 by means of his drifting torpedoes1 similar to those employed by him at ,boulogne1 but considerably improved1 still the ,english ,government refused to have anything further to do with him or his schemes4 ,england1 at that time1 being mistress of the seas1 it was clearly her interest to make the world believe that ,fulton's schemes were impracticable and absurd4 ,earl ,st4 ,vincent1 in a conversation with ,fulton1 told him in very strong language1 that ,pitt was a fool for encouraging a mode of warfare1 which1 if successful1 would wrest the trident from those who then claimed to bear it1 as the sceptre of supremacy on the ocean4,c ,wearied with incessant applications and neglect1 and with failures1 not with his inventions1 but in inducing governments to accept them1 he left ,england in #ahjf1 and returned to his native country4 ,application to ,congress for ,help4--,arrived there1 he lost no time in solicitating aid from ,congress to enable him to carry out experiments with his torpedoes and submarine boats1 practice alone in his opinion being necessary to develop the extraordinary powers of his invention1 as an auxiliary to harbour defence4 ,by incessant applications to his government1 and by circulating his torpedo book,d among the members1 in which he had given detailed accounts of all his previous experiments in ,france and ,england1 and elaborate plans for rendering ,american harbours1 etc41 invulnerable to ,british attack1 a ,commission was appointed to inquire into and practically test the value of these schemes4 ,they were as follows3-- #a4--;,drifting ,torpedoes4--,two torpedoes connected by a line floated in the tide at a certain depth1 and suffered to drift across the bows of the vessel to be attacked2 the coupling line being arrested by the ship's cable would cause the torpedoes to be forced under her bottom2 this plan is represented and will be readily understood by ,fig4 #c4 #b4--;,harpoon ,torpedo4--,a torpedo attached to one end of a line1 the other part to a harpoon1 which was to be fired into the bows of the doomed vessel from a piece of ordnance mounted in the bows of a boat1 specially constructed for the purpose2 the line being fixed to the vessel by the harpoon1 the current1 if the vessel were at anchor1 or her progress if underweigh1 would carry the torpedo under her bottom4 ,fig4 #b represents this type of ,fulton's submarine infernal machine4 #c4--,spar ,torpedo4--,a torpedo attached to a spar suspended by a swivel from the bowsprit of a torpedo boat1 so nearly balanced1 that a man could easily depress1 or elevate the torpedo with one hand1 whilst with the other he pulled a trigger and exploded it4 #d4--;,block ,ship4--,block ships1 that is vessels from #ej to #ajj tons1 constructed with sides impervious to cannon shot1 and decks made impenetrable to musket shot4 ,a spar torpedo a1 a1 a1 to be carried on each bow and quarter ,fig4 #d represents this curious craft4 ,stationary ,mines4--,stationary buoyant torpedoes for harbour defence1 to be fired by means of levers attached to triggers4 ,this kind of mine is shown at ,fig4 #a4 #e4--;,cable ,cutters4--,cable cutters1 that is submarine guns discharging a sharp piece of iron in the shape of a crescent1 with sufficient force to cut through ship's cables1 or other obstructions4,e ,practical ,experiments4--,various and exhaustive experiments were carried out in the presence of the ,commissioners1 tending generally to impress them with a favourable view of ,fulton's many projects4 ,as a final test1 the sloop ,argus was ordered1 under the superintendence of ,commodore ,rodgers1 to whom ,fulton had previously explained his mode of attack1 to be prepared to repel all attempts made against her by ,fulton1 with his torpedoes4 ,defence of the ,argus4--,though repeated attempts were made1 none were successful1 owing to the energetic1 though somewhat exaggerated manner in which the defence of the sloop had been carried out4 ,she was surrounded by numerous spars lashed together1 nets down to the ground1 grappling irons1 heavy pieces of metal suspended from the yard arms ready to be dropped into any boat that came beneath them1 scythes fitted to long spars for the purpose of mowing off the heads of any who might be rash enough to get within range of them4 ,as ,robert ,fulton very justly remarked1 a system1 then only in its infancy1 which compelled a hostile vessel to guard herself by such extraordinary means could not fail of becoming a most important mode of warfare4 ,three of the ,commissioners reported as favourably as could be expected1 considering its infancy1 on the practical value of ,fulton's scheme of torpedo warfare4 ,congress refuse aid4--,but on the strength of ,commodore ,rodgers's report1 which was as unfair and prejudiced1 as the others were fair and unprejudiced1 ,congress refused ,fulton any further aid1 or to countenance any further experiments that he might still feel inclined to prosecute4 ,though undeterred by this fresh instance of neglect1 and still having a firm belief in the efficacy of his various torpedo projects1 yet other important matters connected with the improvement of the steam engine occupied his whole time and prevented him from making any further experiments with his submarine inventions4 ,mode of ,firing1 #ahbi4--,up to #ahbi1 that is to say for nearly sixty years after the invention of torpedoes1 mechanical means only were employed to effect the ignition of the torpedo charges1 such as levers1 clockwork1 and triggers pulled by hand2 with such crude means of exploding them1 it is not extraordinary to find1 that all the attempts made to destroy hostile ships1 resulted in failure4 ,illustration3 ,,fulton',s ,,torpedoes4 ,,plate ,i ,briefly reviewing the history of the torpedo during its first period of existence1 viz41 from ,captain ,bushnell's invention of submarine magazines in #agge1 down to the introduction of electricity1 as a means of exploding submarine mines1 by ,colonel ,colt1 in #ahbi1 we find that due to the unwearied exertions1 and numerous experiments carried out by ,captain ,bushnell1 ,mr4 ,r4 ,fulton and others1 the following very important principles in the art of torpedo warfare were fully proved3-- #a4--,that a charge of gunpowder could be exploded under water4 #b4--,that any vessel could be sunk by a torpedo1 provided only the charge were large enough4 #c4--,that it was possible to construct a boat which could be navigated1 and remain for several hours under water1 without detriment to her crew4 #d4--,that a ship at anchor could be destroyed1 by means of drifting torpedoes1 or by a submarine or ordinary boat1 armed with a spar torpedo4 #e4--,that a vessel underweigh could be destroyed by means of stationary submarine mines1 and by the harpoon torpedo4 ,these principles1 which at the time were fully admitted1 laid the foundations of the systems of torpedo warfare1 that are at the present day in vogue1 all over the world4 ,second ,epoch4--,the second epoch in the life of the torpedo dates from #ahbi1 when ,colonel ,colt1 then a mere lad1 commenced experiments with his submarine battery4 ,colt's ,experiments4--,his first public essay1 was on the #dth ,june1 #ahdb1 when he exploded a case of powder in ,new ,york harbour1 while himself standing at a great distance off4 ,having by numerous successful experiments satisfactorily proved that vessels at anchor could be sunk by means of his electrical mines1 ,colonel ,colt engaged to destroy a vessel underweigh by similar means1 which feat he successfully accomplished on #acth ,april1 #ahdd4 ,colt's ,electric ,cable4--,the electric cable as used by ,colonel ,colt1 was insulated by cotton yarn1 soaked in a solution of asphaltum and beeswax1 and the whole enclosed in a metal case4 ,colt's ,reflector4--,on examining ,colt's papers after his death1 one was found illustrating one of his many devices for effecting the explosion of a submarine mine at the proper instant4 ,description of ,reflector4--,one set of conducting wires from all the mines is permanently attached to a single pole of a very powerful firing battery1 the other wires lead to metal points which are attached to marks on a chart of the channel in front of the operator and which marks correspond with the actual positions of the mines in the channel4 ,a reflector1 is arranged to throw the image of a hostile vessel on the chart1 and as this image passes over either of the wire terminations on it1 the operator with the other battery wire1 completes the circuit1 and explodes the torpedo1 over which by her image thrown on the chart1 the vessel is supposed to be at that precise moment4,f ,in his experiment with a vessel under weigh1 ,colt had probably taken the precaution of laying down several circles of mines1 and thus aided by cross staffs1 ensured the experiment being a success4 ,with regard to the invention of the word torpedo1 for submarine infernal machines1 ,dr4 ,barnard in his life of ,colt says1 that ,fulton used the word torpedo1 probably on account of its power of stunning or making torpid1 and that a long way through the water1--in so naming it1 he buildeth better than he knew1 for ,colt's torpedoes being fired by electricity may with special fitness take its name from the electric eel4,g ,theoretical ,knowledge4--,though many opportunities have occurred during the last thirty-five years for practically testing the effectiveness of torpedoes when employed on actual service1 especially during the ,american ,civil ,war 7#ahfa-fe7 and the late ,turco-,russian ,war 7#ahgg-gh71 yet in so far as the offensive and electrical portion of submarine warfare is concerned1 our knowledge of them is still principally theoretically4 ,failure of ,offensive ,torpedoes4--,the manipulation of the ordinary spar or outrigger torpedo boats1 and of the various automatic torpedoes1 appears simple enough1 when practice is made with those submarine weapons during peace time1 also the results of such practice is without doubt uniformly successful1 yet when the crucial test of actual service is applied1 as was the case during the war of #ahgg1 with the ,whitehead and spar torpedoes1 then a succession of failures had to be recorded4,h ,the cause of this want of success in war-time with offensive torpedoes1 lies in the fact1 that during peace time the experiments and practice carried out with them1 are done so1 under the most favourable circumstances1 that is to say in daylight1 and the nerves of the operators not in that high state of tension1 which would be the case1 were they attacking a man-of-war on a pitch dark night1 whose exact position cannot be known1 and from whose guns at any moment a sheet of fire may be belched forth1 and a storm of shot and bullets be poured on them1 whilst on actual service1 this would in nine out of ten instances be the case4 ,some uncertainty must and will always exist in offensive torpedo operations when carried out in actual war1 where1 as in this case1 the success of the enterprise depends almost wholly on the state of a man's nerves1 yet this defect1 a want of certainty1 may to a considerable extent be eradicated were means to be found of carrying out in time of peace1 a systematic practice of this branch of torpedo warfare1 under circumstances similar to those experienced in war time1 and this is not only possible1 but practicable4 ,moral ,effect of ,torpedoes4--,we now come to the moral effect of torpedoes1 which is undoubtedly the very essence of the vast power of these terrible engines of war4 ,each successive war that has occurred1 in which the torpedo has taken a part1 since ,captain ,bushnell's futile attempt in #agge to destroy our fleet by drifting numerous kegs charged with gunpowder down the ,delawarre1 teem with proofs of the great worth of torpedoes in this respect alone4 ,that such a dread of them should and always will be met with in future ,naval wars1 at times creating a regular torpedo scare or funk1 is not extraordinary1 when it is remembered that these submarine weapons of the present day1 are capable of sinking the finest ironclad afloat1 and of launching into eternity without a moment's warning or preparation1 whole ships' crews4 ,the torpedoes existing at the present day have1 without doubt1 reached a very high degree of excellence1 in so far as their construction1 fuzes1 cables1 c41 both electrically and mechanically1 is concerned1 but much has yet to be done to develop their actual effectiveness4 ,the result of the numerous and exhaustive experiments that have of late years been carried out by ,england1 ,america1 and ,europe prove that the necessary distances between stationary submarine mines are by far greater than those within which the explosions are effective4 ,therefore it will be found necessary to supplement those submarine harbour defences1 by automatic torpedoes that can be controlled and directed from the shore1 as well as by specially constructed torpedo boats4 ,automatic ,arrangements4--,and to ensure certainty1 which is the desideratum in torpedo warfare1 circuit closers1 or other automatic arrangements for exploding the submarine mines1 must be employed1 as the system of firing them by judgment is not at all a sure one4 ,ship ,defence4--,the problem1 which occupies the attention of ,naval and other scientific men1 at the present day1 is how best to enable a ship to guard herself against attacks from the fish and other automatic torpedoes1 and this without in any way impairing her efficiency as a man-of-war4 ,the means of such defence1 should most certainly be inherent in the vessel herself1 outward methods1 such as nets1 booms1 etc41 are to great extent impracticable1 besides one of the above mentioned torpedoes1 being caught by such obstructions would1 on exploding1 most probably destroy them1 thus leaving the vessel undefended against further attacks4 ,mechanical ,mines4--,several ingenious methods have of late been devised for the purpose of obviating one of the principal defects common to all kinds of mechanical submarine mines1 the most efficient and practical of which will be found fully described in the following pages1 viz41 the great danger attendant on the mooring of such mines2 but as yet1 no really practical mode of rendering mechanical mines safe1 after they have once been moored and put in action1 has been discovered1 were such to be devised1 a very difficult and extremely important problem of defensive torpedo warfare would be solved4 ,electrical ,mines4--,in regard to electrical submarine mines1 much has been done by torpedoists in general to simplify this otherwise somewhat complicated branch of defensive torpedo warfare1 by adopting the platinum wire fuze1 in the place of the high tension one1 by the employment of ,leclanch firing batteries1 by the simplification of the circuit closer1 and discarding the use of a circuit breaker1 by altering the form of torpedo case1 and whenever possible by enclosing the circuit closer in the submarine mine4 ,the necessity of a very elaborate system of testing should1 if possible1 be overcome1 for a system of submarine mines that requires the numerous and various tests that are at the present day employed1 to enable those in charge of them to know for certain that when wanted the mines will explode1 cannot be considered as adaptable to actual service4 ,it must be remembered that the safety of many ports1 etc41 will in future wars depend almost entirely on the practical efficiency of electrical and mechanical mines4 ,as yet1 in actual war1 little or no experience has been gained of the real value of a mode of coast defence by electrical mines1 excepting from a moral point of view1 though in this particular they have most undoubtedly been proved to be exceedingly effective4 ,a submarine mine much wanted on active service1 is one that can be carried on board ships1 capable of being fitted for use at a moment's notice1 and of being easily and rapidly placed in position by the ordinary boats of a man-of-war4 ,it should be a self-acting electrical mine1 with the circuit closing apparatus enclosed in the torpedo case1 and capable of carrying about #ajj lbs4 of guncotton4 ,this form of mine would be found extremely useful to secure the entrance to a harbour1 etc41 where ships might happen to be anchored for the night1 or which might have been wrested from the enemy1 etc4 ,they should be capable of being placed in position and picked up again1 in the shortest possible space of time4 ,offensive ,torpedoes4--,coming to the question of offensive torpedoes there still seems to be a great difference of opinion as to the real value of the ,whitehead fish torpedo1 and this point will never be finally settled until that weapon has been more thoroughly tested on actual service2 from a specially built torpedo boat1 by which is meant a ,thornycroft or ,yarrow craft1 the spar torpedo would seem to be the most effective weapon4 ,torpedo vessels for the special purpose of experimenting with the ,whitehead torpedo have been built by ,england1 ,america1 and several continental governments1 so that we may soon hope to get some more decided opinion as to the utility of that weapon4 ,when manipulated from the shore1 or large ships1 the ,lay torpedo boat1 if only its speed be increased will prove an exceedingly effective submarine weapon1 for the purposes of offence1 active defence1 or clearing harbours1 etc41 of mines1 in fact1 it may be more truly said of this weapon1 than of the ,whitehead1 that it can do everything but speak4 ,captain ,harvey has greatly improved his towing torpedo1 but it is still a somewhat complicated and difficult weapon to manipulate by ordinary persons1 that is1 those not specially trained for the work4 ,drifting torpedoes under certain circumstances should prove invaluable1 but little or no improvement has been effected in this direction4 ,submarine boats have also remained in statu quo1 though for the purpose of clearing an enemy's harbour of mines1 it seems impossible to devise any better method4 ,electric lights are now universally adopted for use on board ship1 and will play a very important part in the defence of ships against torpedo attacks in future wars4 ,glancing back on what has been effected in the matter of improving the system of torpedo warfare in all its branches during the last few years1 with the exception of the vast improvements in the form and construction of steam torpedo boats1 their engines1 etc41 very little has been done1 owing principally to the want of that practical knowledge which unfortunately can only be gained from their employment in actual war4 ,the late ,turco-,russian war afforded a splendid opportunity for applying the crucial test of actual service to both the offensive and defensive branches of torpedo warfare1 yet little or no light was thrown on the somewhat shadowy subject of submarine warfare4 ,the present struggle between ,peru and ,chili may furnish some experience1 but it will not be very satisfactory1 as hardly any knowledge of manipulating torpedoes is possessed by either side4 ,,footnotes3 ,footnote ,a3 ,c4 ,d4 ,colden's ,life of ,fulton4 ,footnote ,b3 ,c4 ,d4 ,colden's ,life of ,fulton4 ,footnote ,c3 ,c4 ,d4 ,colden's ,life of ,fulton4 ,footnote ,d3 ,torpedo ,warfare1 by ,r4 ,fulton1 #ahaj4 ,footnote ,e3 ,c4 ,d4 ,colden's ,life of ,fulton4 ,footnote ,f3 ,johnston's ,cyclopdia4 ,footnote ,g3 ,armsmear4 ,footnote ,h3 ,see ,chapter ,,vii4 ,,chapter ,,ii4 ,,defensive ,,torpedo ,,warfare4--,,mechanical ,,mines4--,,mechanical ,,fuzes4--,,mooring ,,mechanical ,,mines4 ,,by defensive torpedo warfare is meant the protection of harbours1 rivers1 etc41 by means of various descriptions of torpedoes moored beneath the surface of the water4 ,submarine1 or sea mine1 is the term that has been generally adopted to designate this particular species of torpedo4 ,submarine ,mines4--,defence in ,future ,wars4--,the very conspicuous part played by submarine mines1 in the many wars that have taken place since the introduction of the torpedo as a legitimate mode of ,naval warfare1 when their manipulation was comparatively little understood1 and construction very imperfect1 proves that1 with the experience so gained1 and the vast improvements that have been1 and are daily being effected1 in all that appertains to the art of torpedo warfare1 the protection of harbours1 etc41 will in future wars depend in a great measure on the adoption of a systematic and extensive employment of submarine mines4 ,the utility and power of this mode of coast defence has been fully exemplified in actual war1 more especially during the ,franco-,german war 7#ahgj-a7 and the late ,turco-,russian war 7#ahgg-h74 ,torpedoes in the ,franco-,german ,war4--,in the former instance1 the superiority of the ,french over the ,germans1 in the matter of ships1 was more than neutralised1 by the use on the part of the latter of electrical1 mechanical1 and dummy mines for the protection of their harbours1 etc4 ,in regard to the utility of the latter1 it is on record that a certain ,german port was entirely defended by dummy mines1 the ,burgomaster of that place having been unable to obtain men to place the active mechanical ones in position1 owing to the numerous and serious accidents that had previously occurred in other ,german ports at the commencement of the war1 in mooring the latter kind of submarine mine4 ,the effect1 so far as keeping the ,french fleet at a distance was concerned1 was precisely the same1 as though active instead of dummy mines had been employed1 thus still further proving the vast moral power possessed by torpedoes4 ,torpedoes in the ,russo-,turkish ,war4--,in the war of #ahgg1 the ,turks1 though possessing a powerful fleet in the ,black ,sea and flotilla on the ,danube1 made little or no use of their superiority over the ,russians in this respect4 ,they failed to even attempt to destroy the bridges formed by the ,russians over the ,danube1 nor did they make any attempt to capture ,poti1 re-take ,kustendje1 or to create diversions on the ,russian coast in the ,black ,sea4 ,had the latter service alone been effectually carried out1 by which means1 a large force of the enemy would have been held in check1 immense help would have been afforded to the ,ottoman armies in ,europe and ,asia4 ,again1 during the whole of the war1 the ,russian port of ,odessa was never sighted1 and ,sebastopol only once by the ,ottoman fleet4 ,cause of ,failure of the ,ottoman ,fleet4--,the cause of this repeated neglect on the part of the ,turkish fleet may be traced almost entirely to the assumption 7which in nine out of ten cases was an erroneous one7 on the part of the ,naval ,pashas and ,beys that every ,russian harbour1 etc41 was a mass of submarine mines1 and this in several instances extending many miles to seaward4 ,so also1 some of the many failures experienced by the ,russians in their numerous torpedo boat attacks1 were due in a great measure to an erroneous supposition on the part of the captain of the ,russian steamer1 ,constantine 7employed to convoy the torpedo boats71 that the ,turks had defended the entrance1 to a distance of some miles to seaward1 of their harbours1 etc41 and thus the torpedo boats were dispatched to the attack some miles off the entrance1 causing them1 owing to the darkness1 to enter the harbour in which the ,turkish vessels were lying1 in a very straggling manner4 ,and to a similar reason the failure of the ,russians to capture ,sulina1 in the attack made on that place in ,october1 #ahgg1 was principally owing to their not daring to send their ,popoffkas to attack from the sea4 ,one of the chief points of usefulness of an extensive and systematic employment of submarine mines1 will be to minimise the number of vessels necessary for the protection of harbours1 etc41 thus enabling a far larger number of ships to operate at sea against those of an enemy1 this especially applies to countries like ,england and ,america possessing a large extent of seacoast1 numerous harbours1 rivers1 etc41 which it would be necessary to defend in the event of war4 ,science of ,torpedo ,warfare4--,the science of defensive torpedo warfare may be considered to consist of3-- #a4--,the arrangement of the mines in positions1 such that it would not be possible for a hostile vessel attempting to force a passage into a harbour1 etc41 defended by such means1 to pass more than one line of them1 without coming within the destructive radius of some one or other of the remaining mines4 ,,note4--,the difficulty of attaining the above effect1 lies in the fact that the destructive radius of a submarine mine1 is considerably less than the distance that must be maintained between them1 to prevent injury by concussion to the cases1 circuit closers1 electric cables1 etc41 of such mines on the explosion of an adjacent one4 ,as an illustration of the above1 take the case of a #ejj lb4 guncotton submarine mine4 ,now the destructive radius of a sea-mine is found by the formula ,r #crt7#cb ,c71 where ,r is the destructive radius in feet of a mine moored at its most effective depth1 and ,c is the charge 7guncotton7 in lbs4 ,in the above case ,r would be about #bd feet1 which in so far as the actual destruction of a ship is concerned1 may be taken as correct1 but if injury to a vessel's engines1 boilers1 etc41 be also taken into consideration1 and as the vessel would most probably be underweigh on such an occasion1 this would be a very vital and important consideration1 ,r would under those circumstances be more than doubled4 ,now the necessary interval for safety between such mines1 according to torpedo authorities1 is equal to #aj ,r1 and should certainly be not less than #h ,r1 which in this case would give about #bjj feet1 therefore assuming the radius of destruction to be #ej feet1 it is seen that there would be under those conditions a clear undefended space of about #ajj feet between each couple of #ejj lb4 mines in the same line4 #b4--,the combined arrangement of submarine mines with forts and batteries1 in such a manner1 that every one of the former shall be well covered by the guns of the latter1 and also that it would be impossible for an enemy's ships to get within effective range of the forts1 or batteries1 without moving over ground where mines were laid4 ,,note4--,this applies to the defence of the more important harbours1 etc41 in which case the submarine mines 7which would be chiefly electrical ones7 would only act as auxiliaries to the land defences4 ,to effectually carry out the above1 there can be no question but that they who plan the forts1 etc41 should also plan the systems of submarine defence4 ,a harbour1 river1 etc41 which it is necessary to protect by electrical submarine mines1 etc41 and where no land defences exist1 should have its mines supported by a powerful ship or ships1 as maybe thought desirable4 ,success in ,torpedo ,warfare4--,the two most important conditions essentially necessary to the successful employment of torpedoes1 both offensive and defensive1 are3-- #a4 ,,certainty ,,of ,,action4 #b4 ,,simplicity ,,of ,,manipulation4 ,without the former this mode of ,naval warfare is comparatively useless1 while without the latter the former condition is rarely obtained1 more especially in the case of offensive torpedoes4 ,submarine mines are divided into separate classes1 viz43-- #a4 ,,mechanical ,,mines4 #b4 ,,electrical ,,mines4 ,mechanical ,mines4--,by this description of submarine mines1 is meant those whose charges are fired by mechanical means alone4 ,mechanical ,mines in the ,american ,civil ,war4--,during the civil war of ,america 7#ahfa-e71 the ,confederates depended almost entirely on mechanical submarine mines for the protection of their harbours1 rivers1 etc41 and to this extensive use of such mines may be traced nearly the whole of the ,federal disasters afloat4 ,in the principal wars that have subsequently occurred1 though this form of submarine mine has been to a certain extent used1 it has generally been only as an auxiliary to the more effective electrical torpedo1 and owing to the deterrent effect produced by the numerous torpedo successes that characterised the ,american ,civil ,war1 on ,naval ,commanders1 etc41 few vessels have been destroyed by their means1 the effect of the employment of defensive torpedoes having been almost wholly a moral one4 ,mechanical ,mines for ,coast ,defence4--,the experience hitherto gained1 with regard to the employment of mechanical mines for coast defence in actual war1 proves that they will be found exceedingly valuable in the following positions3-- #a4--;,in combination with booms or other obstructions placed in defence of narrow channels1 etc41 which are intended to be completely blocked up4 #b4--;,in shallow water on the flanks of electrical mines4 #c4--;,in protecting unfrequented bays1 channels1 etc41 and a long line of seacoast1 which may otherwise be entirely undefended4 ,,note4--,in this latter instance1 though the mines may not be covered by any guns1 still they will be of great use1 in so far1 that being mechanical ones1 they cannot be rendered useless by the process of cutting cables1 etc41 but must be destroyed1 which in time of peace is a work of considerable labour and danger1 and1 therefore1 would in the time of war1 cause at the very least1 serious delay to an enemy desirous of effecting a landing1 etc41 at a point so protected4 ,there are numerous objections against their employment1 the principal ones being3-- #a4--,that they are all1 more or less dangerous to place in position4 #b4--,that they cannot be tested when moored4 #c4--,that they are as dangerous to friend as to foe1 when once placed in action4 #d4--,that an exploded1 or known damaged mine cannot be replaced4 ,,note4--,the above objections1 especially #b and #c1 constitute without doubt very serious defects in a system of defence by mechanical mines1 and in the case of purely mechanical ones1 it seems almost impossible to eradicate any of them1 though1 notwithstanding1 under the particular circumstance before-mentioned1 these species of defensive torpedo will be found extremely useful4 ,the ,advantages of ,mechanical ,mines4--,they possess a few advantages1 which are as follows3-- #a4--,they are comparatively cheap4 #b4--,they can be kept in store and ready for use at a moment's notice4 #c4--,they do not require specially trained men to manipulate them4 #d4--;,extempore ones can be easily and readily made4 ,best ,kinds of ,mechanical ,mines4--,among the very numerous and various kinds of mechanical submarine mines that have been devised the following may be considered as the most effective1 and practicable of them all3-- #a4--;,,frame ,,torpedoes4 #b4--;,,buoyant ,,mines4 ,this includes3-- a4--,,barrel ,,mine4 b4--,,brook',s ,,mine4 #c4--,,singer',s ,,mine4 #d4--,,mcevoy',s ,,improved ,,mine4 #e4--;,,extempore ,,mine4 ,frame ,torpedoes4--,this form of defensive mine is shown at ,fig4 #f4 ,it consists of a frame work which is formed of four strong timbers a1 a1 a1 a1 these being kept parallel and only a few feet apart by means of cross timbers b1 b4 ,a cast-iron torpedo c1 c1 c1 in the shape of a shell1 is bolted to the head of each of the timbers a1 a1 a1 containing about thirty pounds of fine grained gunpowder1 and fitted with a percussion fuse1 which is so placed that it would come into contact with a vessel striking against the framework1 directly or not4 ,one end of the frame is securely anchored1 the other1 that on which the torpedoes are fixed1 is kept at its proper distance below the surface of the water by means of chains1 d1 d1 and anchors4 ,to prevent the frame from sinking when sodden with water1 the uprights e1 e1 are provided4 ,this form of mechanical mine1 which performs the double function of torpedo and obstruction1 was much used by the ,confederates1 and found extremely useful1 no passage was attempted to be forced by the ,federals where these torpedoes were known to be placed4 ,stake ,torpedo4--,fig4 #g represents another form of the frame torpedo4 ,it consists of a piece of timber1 a1 its heels secured by a heavy metal shoe b1 working in a universal joint in the mooring1 c4 ,at the head of the piece of timber is secured a torpedo d1 containing about fifty pounds of gunpowder1 and fitted with four or five sensitive fuzes4 ,the proper angle of inclination is obtained by securing the upper end of the timber to an anchor as shown at e4 ,as a proof of the efficiency of this species of mechanical mine1 even though having been in position for a great length of time1 the ,u4,s4 gunboat1 ,jonquil1 was nearly destroyed whilst attempting to remove some similar torpedoes which had been in position for two years4 ,illustration3 ,,frame ,,torpedoes1 ,,buoyant ,,mechanical ,,mines4 ,,plate ,,ii4 ,the ,barrel ,torpedo4--,one description of this form of mechanical submarine mine is shown at ,fig4 #h4 ,it consists of a barrel a1 to the ends of which are attached two cones of pine b1 b1 for the purpose of preventing the current from turning the mine over4 ,to ensure its being watertight1 pitch is poured into the interior through the bunghole1 and the barrel rolled about1 so that the inside may be evenly covered4 ,the outside was also thoroughly coated with pitch4 ,these mines usually contain about #ajj lbs4 of gunpowder1 and are exploded by means of percussion or chemical fuzes 7c1 c1 c17 generally five in number1 screwed into sockets on each side and on the top of the bilge of the barrels4 ,to keep them upright a weight d is hung below the mine4 ,this kind of mechanical mine was much used by the ,confederates1 and to some extent by the ,turks in their late war with ,russia4 ,they are cheap1 convenient1 and under certain circumstances very effective4 ,one of the objections to their use is the difficulty of mooring them securely in strong currents1 as otherwise they are very liable to shift their positions4 ,three ,confederate vessels were hoisted by their own petards1 from this cause4,i ,brook's ,torpedo4--,another form of buoyant mechanical mine is represented at ,fig4 #i4 ,it was designed for the express purpose of preventing its discovery by dragging1 etc41 by the enemy4 ,it consists of the torpedo case a1 formed of copper1 which is attached to a spar b1 the lower end of which is secured to an universal joint in its anchor c4 ,five percussion or chemical fuzes d1 d1 d1 are screwed into the head of the copper case4 ,turtle ,torpedo4--,to increase the danger and uncertainty of any attempt to remove this form of buoyant mine1 a turtle torpedo ,a1 is attached to it by a wire e4 ,this torpedo contains about #ajj lbs4 of gunpowder1 and is exploded by means of a friction primer which passes through a watertight joint f1 and is attached to the wire e4 ,whether this combination would prove effective1 has yet to be seen1 but the buoyant mine alone was considered one of the most dangerous used by the ,confederates4 ,singer's ,mechanical ,mine4--,an elevation and section of this form of mechanical mine is shown at ,fig4 #aj4 ,it consists of an air chamber a1 and a powder chamber b2 in the latter is fixed a rod of iron c1 one end of which rests in a cup formed in a lug d1 where there is a screw by means of which the rod c may be screwed against the bottom of the torpedo case1 on the interior4 ,in the cup is placed the fulminating substance4 ,a heavy cast iron cap ,a ,b rests upon the top of the case and is prevented from falling off by a low rim of tin1 which enters an aperture in the cap as at e3 a wire f connects this cap with a pin g1 which keeps a plunger h at rest4 ,the head of this plunger h is directly beneath the bottom of the rod c1 within the case2 by means of a spring i1 directly the pin g is drawn out1 which is done by a hostile vessel striking against the mine and knocking off the cap ,a ,b1 the plunger h is forced against the bottom of the case and drives the rod c into the cup containing the fulminate1 and so explodes the torpedo4 ,the case of these mines1 as used by the ,confederates1 was formed of tin1 and they contained from #ej to #ajj lbs4 of powder4 ,a safety pin k is provided to prevent a premature explosion due to the pin g being accidentally withdrawn4 ,this form of submarine mine was one of the most successful and most extensively employed of all1 on the part of the ,confederates4 ,though no accidents are stated to have occurred in placing this mine in position1 yet the fact of the iron rod c having to be fixed for action1 and that close against the interior of the bottom of the case1 before the charge of powder has been put in1 is an element of great danger1 for a comparatively slight blow beneath it1 which might easily occur in transport1 etc41 would explode the torpedo prematurely4 ,mc,evoy's ,improved ,singer's ,mine4--,to obviate this defect ,captain ,mc,evoy has designed an improved mode of ignition for ,singer's mine4 ,this is shown at ,fig4 #aa4 ,the form of case1 and arrangement of heavy cap are similar to those in ,singer's mine4 ,the mode of ignition is as follows3--,in the powder chamber b is fixed a friction fuze f1 which by means of a piece of wire secured to a length of chain k1 k1 is connected with the heavy cast iron cap ,a ,b4 ,the piece of wire passes through a diaphragm of thin metal h1 which is soldered all around1 thus forming a complete watertight joint4 ,premature explosion is prevented by passing a link of the chain1 through a slot in the bolt c1 securing it there by a pin of bent wire l4 ,the dotted line of chain k1 k1 shows its position during the process of mooring this form of ,singer's torpedo4 ,the manner of lowering this and also ,singer's mine is shown at ,fig4 #ab4 ,a buoy x1 is attached by means of a line1 in the former case to the pin l1 ,fig4 #ab1 in the latter case to the pin k1 ,fig4 #aj1 the pulling out of either1 sets their respective mines in action4 ,illustration3 ,,singer',s ,,and ,mc,,evoy',s ,,mechanical ,,mines4 ,,plate ,,iii4 ,mathieson's ,cement ,safety ,plug4--,in the place of the safety pin l1 ,fig4 #aa1 employed by ,captain ,mc,evoy in his improved form of ,singer's mine1 ,quartermaster-,sergeant ,mathieson1 late ,royal ,engineers1 employs a plug or disc of soluble cement1 so arranged that the action of the sea-water after the mine has been placed in position destroys the plug or disc1 and so frees the chain which is connected with the fuze and the heavy cap of the torpedo4 ,this plan does away with the necessity of using a buoy and line as shown in ,fig4 #ab1 and also affords ample time for the men engaged in mooring the mine to get far away before it is ready for action4 ,mechanical ,mine4--,the extempore mechanical submarine mine1 shown at ,fig4 #ac1 will be found to possess all the qualities which are necessary to a perfect mine of that description4 ,it is extremely simple1 it can be readily and quickly made1 all the materials of which it is constructed are at hand on board every man-of-war1 and it is certain in its action4 ,it consists of a barrel a1 which is thoroughly coated inside and out with hot pitch1 etc41 to make it watertight1 a block of wood b1 secured to the top of the cask a1 and having a recess cut in it to receive a round shot c1 also a hole through which a strop d1 is passed1 and another hole to receive a toggle e4 ,at the bottom of the cask on the inside1 is fixed a wooden frame work f1 f1 to the top of which two ordinary gun friction tubes are fixed g1 g4 ,a piece of wood h1 is secured to the bottom of the cask on the outside1 bored with two holes1 one to receive a thin iron rod i1 the other for the safety pin k4 ,wires x1 x1 secure the gun tubes g1 g1 to one end of the iron rod i1 the other end of which is connected by means of a rope lanyard to the shot c4 ,weights are slung beneath the barrel to keep the mine upright4 ,the principle of action of this form of mechanical mine is precisely similar to that of ,captain ,mc,evoy's improved ,singer's mine1 and need not1 therefore1 be described4 ,mc,evoy's ,mechanical ,primer4--,a sectional view of this apparatus is represented by ,fig4 #ad4 ,it consists of two brass tubes fitting accurately one within the other1 of which a1 a1 is the inner one4 ,to this inner tube are affixed two brass diaphragms b1 b4 ,a brass spindle c1 carries a weight d1 which is regulated by a spring1 e4 ,a locking rod1 f1 moves in a ball and socket joint at g4 ,a hammer h1 which is shown in ,fig4 #ad1 at full cock1 is kept in that position by the rod f4 ,a vessel1 striking the mine1 in which this apparatus is placed causes the weight1 d1 to cant over1 allowing the rod1 f1 to be forced upwards by means of the spring e1 and so frees the hammer h1 which falls on a nipple i1 on which is placed the percussion substance1 and so explodes the mine4 ,mc,evoy's ,papier ,mach ,safety ,plug4--,to prevent a premature explosion during transport1 etc41 of a mine in which this apparatus is placed1 a plug of papier mach1 which is soluble in water1 is inserted in the two spaces p1 p1 by which the spindle c1 is prevented from moving to one side or the other4 ,the use of a papier mach1 instead of a cement plug for the purposes of safety1 is a great improvement1 as by the simple process of pressure1 any period of time that it is necessary should elapse before the complete destruction of the plug1 can be readily and certainly obtained1 which when a cement plug1 formed of different ingredients is used1 is not always the case4 ,mc,evoy's ,mechanical ,mines4--,captain ,mc,evoy has also devised a plan1 whereby a mechanical mine of the foregoing form may be placed in a state of safety1 even after it has been rendered active4 ,in the place of the aforesaid papier mach wad at p1 ,fig4 #ad1 he uses a plunger which fits into the cavity p1 of the heavy weight d4 ,this plunger is always kept in a position clear of the weight by means of a spiral spring1 unless it is desired to render the mine inactive when the plunger is forced into the aforesaid cavity and kept there by means of a pin inserted above it4 ,above this there is another plunger1 acted on by a spiral spring sufficiently powerful to enable it to force the previous mentioned plunger into the safety position2 this upper plunger is rendered inactive by means of a pin4 ,the mine being placed in position1 that pin which is keeping the lower plunger inserted in the cavity p1 of the weight d1 is withdrawn and the mine rendered active4 ,to the pin of the upper plunger is attached a line which is anchored some distance from the mine in a known position4 ,then to render the mine inactive for the purpose of picking it up1 etc41 it is only necessary to raise the aforesaid line1 and draw out the pin of the upper plunger1 which by means of the strong spiral spring will force the lower plunger into the safety position1 and render the mine inactive4 ,whether this invention is a practicable one or not1 remains to be proved1 but anyhow it is a step in the right direction4 ,illustration3 ,,extempore ,,mechanical ,,mine1 ,,mechanical ,,primers4 ,,plate #d ,abel's ,mechanical ,primer4--,this is shown in section and elevation at ,fig4 #ae 7,a and ,b74 a1 a1 is the powder chamber in which the priming charge is placed2 b is a screw plug to close the chamber2 c is a flexible india rubber tube2 d1 d1 are screw bands2 e is a glass tube containing oil of vitriol enclosed in a lead tube2 f which contains the explosive mixture2 g1 an eye at the head of the primer to receive the firing line2 h1 h are segmental guards2 i is the guard ring2 and j the safety screw pin4 ,this apparatus is screwed into a socket in the upper part of the torpedo case1 as shown at ,fig4 #ae 7,c74 ,mode of ,action4--,when placed in position1 to render the primer ready for action1 the guard ring1 i1 is pulled off1 first having removed the safety pin j1 when the segmental guards h1 h1 will fall away1 leaving the india rubber tube c1 c1 exposed4 ,a sufficient strain being brought on the rope secured to the ring g1 the lead tube f bends1 causing the fracture of the glass tube e1 thus igniting the priming charge and exploding the mine4 ,a submarine mine so fitted may be fired at will1 by bringing a line1 from the ring g1 to the shore1 or it may be made self-acting by connecting two of them together1 etc4 ,percussion and ,chemical ,fuzes4--,many forms of this mode of mechanical ignition have been from time to time devised1 of which the following are the most important ones3-- ,sensitive ,fuze4--,it consists of an inner cylinder a1 a1 ,fig4 #ae1 of composition metal1 #a-a_/b diameter1 and #b-a_/b long1 having a thread cut on its outside1 and a bouching b1 #b-a_/d diameter and #b long with a sexagonal projection c1 for applying a wrench1 also with an external and internal thread4 ,the upper end of the inner cylinder a1 is solid for #a1 and is perforated by three holes d1 d1 d1 in each of which a percussion primer is placed e1 e4 ,a piece of thin1 soft and well annealed copper f is soldered to the upper end of the bouching b1 to keep moisture from the primers1 and is so thin that a slight blow will crush without breaking it4 ,a safety cap can be screwed on to the external thread above the projection c4 ,rain's ,detonating ,composition4--,the detonating composition employed in this and many other forms of percussion fuzes by the ,confederates1 etc41 consisted of a combination of fulminate of mercury and ground glass1 and was invented by1 and is named after1 ,general ,rains1 ,chief of the ,torpedo ,bureau1 at ,richmond1 during the ,civil ,war 7#ahfa-e74 ,so sensitive was this composition that seven pounds pressure1 applied to the head of one of the primers1 would explode it4 ,when required for use the internal cylinder a1 containing the primers e1 e1 is screwed up until contact between them and the copper cap f is secured4 ,mc,evoy's ,percussion ,fuze4--,fig4 #af represents a longitudinal section1 full size1 of the mechanical percussion fuze1 used by ,captain ,mc,evoy in connection with his drifting torpedo1 which latter will be hereafter described4 a is a piece of metal1 having an external and internal thread1 and a projection b1 to which is applied the spanner for screwing it into the torpedo case4 ,this piece a is hollow at its upper end1 and is closed by means of a thin copper dome c1 which is soldered to it4 ,screwed into the piece a is the plug1 or nipple d1 with a hole through it from end to end1 it is rammed full of mealed powder1 and then a fine hole is drilled through the composition4 ,a cavity e at the head of the plug1 or nipple d1 is filled with a fulminating substance4 ,a spiral spring f1 encircles the plug d1 on which a cap g rests2 h is a needle in this cap4 ,the action of this fuze will be readily understood from the plan of the fuze at ,fig4 #af4 ,a safety cap is provided1 which fits into the slots i1 i1 and is fixed there by means of a set screw4 ,improved ,form of ,jacobi's fuze4--,the section shown in ,fig4 #ag is an improved form of the chemical fuze1 invented by ,professor ,jacobi1 and used by the ,russians in their land and sea mines during the ,crimean war 7#ahed-e74 ,it consisted of a small glass tube a1 containing sulphuric acid1 enclosed in a lead cylinder b4 ,a mixture of chlorate of potash and white sugar surrounds the tube and holds it in position2 c is a primer filled with mealed powder in connection with the charge of the mine4 ,the action of this fuze is as follows3--,on a vessel striking against the lead cylinder b1 it is crushed in1 breaking the glass tube containing the sulphuric acid1 and thus causes it 7acid7 to flow into the mixture of chlorate of potash and white sugar1 producing fire1 which by means of the primer c1 passes into the charge1 and explodes the mine4 ,illustration3 ,,mechanical ,,fuzes4 ,,plate ,v4 ,defect of ,chemical ,fuze4--,the defect of the chemical fuze just described is its slow rate of ignition when compared to gunpowder4 ,this may be remedied by adding a small quantity of sulphuret of antimony or perro cyanide of potassium4 ,both the ,turks and the ,germans employed1 as a mode of ignition for their mechanical submarine mines1 the chemical fuze described above1 with but slight modifications in the shape of the lead cylinder and manner of fixing the fuze into the torpedo case4 ,mechanical fuzes1 both percussion and chemical1 which require a blow to effect their ignition1 are to a certain extent defective when applied to submarine mechanical mines 7which are always buoyant ones7 in so far that a hostile vessel passing over ground supposed to be defended by torpedoes of any description1 would do so at as slow a rate of speed as it would be possible to proceed at1 and would1 under those circumstances1 push away rather than strike a buoyant mine1 with which she might come in contact4 ,during the ,american civil war and the ,russo-,turkish war1 especially in the former1 there are several instances on record of vessels passing over buoyant mechanical mines unharmed1 whilst similar vessels have afterwards been destroyed by those self-same mines2 and the only cause for such apparent inconsistency being the above-mentioned one1 viz41 the pushing rather than striking effect produced on a buoyant mine by a vessel under weigh proceeding at a very slow speed1 or merely drifting with the current4 ,steward's ,safety-,cock ,arrangements4--,to obtain security to a certain extent in placing mechanical submarine mines in position1 which1 as has been previously stated1 is one of the defects common to all forms of such torpedoes1 many ingenious methods have been devised1 such as safety caps to their fuzes1 safety pins1 soluble plugs1 c4 ,another method1 suggested by ,captain ,harding ,steward1 ,r4,e41 which it is intended should be used in connection with the other safety arrangements1 is shown at ,fig4 #ah4 ,it consists of a stop-cock ,a1 which1 in connection with a tube1 is introduced between the fuze and the charge4 ,it is so arranged that when the cock is turned in the direction of the tube1 as shown in section ,b at e1 the gas on formation can pass easily through and explode the charge2 but when the cock is shut off1 the gas on formation escapes through the side d1 as shown in section ,c4 ,to prevent destruction of the charge through leakage under the pressure of the water1 the cone in connection with the stop-cock should fit very accurately1 and1 as an additional preventive1 the escape hole should be covered with a waterproof plaster1 which at a moderate depth would keep the water out and yet offer no material resistance to the escape of the gas if the stop-cock were shut off1 as at ,c4 ,the efficiency of this arrangement1 as far as relates to its cutting off the gas from the charge1 has been satisfactorily proved by practical experiments4 ,mooring ,mechanical ,mines4--,this description of defensive torpedo will rarely be used in deep-water channels1 c41 and on account of the impossibility of ascertaining whether such a mine has drifted or otherwise1 it should not be moored in a very rapid current4 ,such being the case1 an ordinary mushroom anchor1 heavy stone1 c41 and single steel wire mooring-rope1 will be generally found quite sufficient to keep such mines in position4 ,when only a few mechanical submarine mines are moored in position1 and at some distance apart1 it would be found a useful plan to moor them each with three anchors1 one anchor being up-stream4 ,by this method1 at low water1 on the up-stream anchor being raised1 the mine would show itself1 and might in that position be approached and rendered inactive4 ,were this plan to be adopted when several such mines are in position1 there would be the danger of the up-stream anchor on being raised1 bringing up to the surface1 and probably in contact with the boat at work1 a mine to which that particular anchor does not belong1 an explosion being the result4 ,,footnotes3 ,footnote ,i3 ,submarine ,warfare1 by ,commander ,s4 ,barnes1 ,u4,s4,n4 ,,chapter ,,iii4 ,,defensive ,,torpedo ,,warfare--continued4 ,,by electrical submarine mines is meant those whose charges are ignited by the agency of electricity4 ,submarine ,mines during the ,crimean and ,american ,wars4--,it was during the ,crimean war 7#ahed-f7 that this description of defensive torpedoes was for the first time employed on actual service4 ,several of the principal ,russian harbours were protected by this form of submarine mine1 but owing to the smallness of their charges1 and to the want of electrical knowledge on the part of the ,russian officers and men in charge of them1 none of the ships of the ,allies were sunk1 or even rendered hors de combat by this mode of harbour defence1 though in several instances ground known to be covered with submarine mines was passed over by both ,english and ,french vessels of war4 ,subsequently the ,confederates1 during the ,american civil war1 employed electrical submarine mines in considerable numbers for the defence of their numerous harbours1 rivers1 c42 but though in so far as the size of the torpedo charges was concerned1 they did not make the same mistake as the ,russians1 yet1 owing to the absence of proper electrical apparatus1 and the want of any practical knowledge of the manipulation of electrical sea mines1 on the part of the ,confederate torpedoists1 they were almost entirely unsuccessful in destroying the ,federal warships2 the ,commodore ,jones being the sole instance1 out of the large number of vessels belonging to the ,northerners which were sunk and severely injured by torpedoes1 of a war steamer being sunk by means of electrical submarine mines4 ,in the ,franco-,german and ,russo-,turkish wars which have lately occurred1 electrical sea mines were very extensively used in coast defence1 but with the exception of the loss of the gunboat ,suna to the ,turks1 during the latter struggle1 by this form of defensive torpedo1 no other damage to vessels resulted from their use1 yet owing to the vast moral power possessed by these submarine weapons1 they were enabled to most effectually carry out the work of defence entrusted to their care4 ,of late years many important discoveries have been made in the science of electricity1 and vast improvements have been effected in electrical apparatus1 to which causes may be traced the vastly improved system of electrical submarine mines as adopted by the ,english1 ,american1 and principal ,european governments at the present day1 as compared with those that have hitherto been employed4 ,the certainty of action when required of electrical submarine mines1 which is of course the desideratum of all torpedoists1 has1 by the improved mode and manner of ascertaining the exact electrical condition of each particular mine1 and of the system as a whole1 which is at present in vogue1 been made almost absolute4 ,advantages of ,electrical ,submarine ,mines4--,this form of defensive torpedo possesses numerous important advantages1 the principal of which are as follows3-- #a4--,they are always absolutely under control4 ,,note4--,by detaching or connecting the firing battery1 which is effected by means of a plug1 key1 c41 they may be respectively rendered harmless1 or dangerous4 ,thus friendly ships may pass over them in safety1 whilst those of the enemy are debarred from so doing4 ,on this account harbours1 c41 protected by such mines are termed ,harbours of refuge4 #b4--;,fresh mines may be added to a system of such defensive torpedoes1 thereby allowing an exploded mine to be replaced4 ,,note4--,this is a very important point in connection with a system of defence by submarine mines1 as in the case of a deep water channel1 a hostile vessel being sunk by one of them1 would not become an obstruction1 as1 were the channel a comparatively shallow one would most probably be the result1 and therefore it would be necessary to put a fresh mine in the place of the exploded one2 this would also apply were a mine to be prematurely ignited1 or if any portion of its firing apparatus were injured4 #c4--;,at night1 or in a fog1 no vessel can pass through a channel1 c41 so protected without affording a means of ascertaining her presence4 ,,note4--,this is also a very important advantage of a system of defence by electrical sea mines1 affording as it does a complete safeguard against surprise4 #d4--,the power of obtaining proof1 without going near it1 by a system of testing that the electrical condition of the mine1 c41 is perfect4 ,,note4--,this again is an extremely important point4 ,for were a charge to become wet1 one of the electric cables of the mine broken1 or damaged1 c41 it would instantly be made apparent at the firing station1 and could be at once remedied4 #e4--,they can be raised for examination1 or removed when no longer required1 with ease and safety4 ,such are some of the chief advantages of employing the agency of electricity to effect the ignition of the charge in a system of defence by submarine mines4 ,defects of ,electrical ,submarine ,mines4--,the following are the chief defects connected with the use of electrical mines3-- #a4--,the number of wires that are required to be used with them4 #b4--,the necessity of employing specially trained men in their manipulation4 ,in time there seems little doubt but that the former obstacle will be to a considerable extent overcome1 but the latter must always be a flaw in an otherwise perfect system of coast defence by submarine mines4 ,rules to be observed in using ,electrical ,submarine ,mines4--,in connection with a system of electrical submarine mines the following rules should be carefully observed3-- #a4--,they should be moored in deep channels1 that is to say1 where the larger class of vessels would in attempting to force a passage be obliged to go4 ,,note4--,mechanical submarine mines should never be used under these circumstances1 as the difficulties of mooring them and keeping them in position would be very considerable1 also a vessel being sunk in a very deep channel would not necessarily block it1 and as a mechanical mine cannot be replaced1 a gap would be left in the defence4 #b4--,they should be placed in the narrowest parts of the channel4 ,,note4--,the object of this rule is evident1 fewer mines being required1 and consequently in the case of electrical ones1 a far less number of wires are needed1 which gives an increase of simplicity1 and consequently more effectiveness4 ,this point should be observed in connection with mechanical1 as well as electrical submarine mines4 #c4--,they should where practicable be moored on the ground4 ,,note4--,the advantages attendant on an observance of this rule are3-- a4--,increased vertical effect4 b4--,avoidance of mooring difficulties4 c4--,less liability of shifting from its original position4 d4--,less chance of its being discovered and rendered useless by an enemy4 e4--,by far heavier charges may be conveniently employed4 #d4--,where possible1 no indication whatever should be given of the position of the mines by their circuit closers1 or in the case of small buoyant ones1 by the mines themselves4 ,,note4--,in some instances this will be almost impracticable1 as for example1 where there is a very great rise and fall of tide4 ,for instance1 at ,noel ,bay in the ,bay of ,fundy1 the rise is over fifty feet4 ,here1 when circuit closers1 or small buoyant mines are used1 both of which ought never to be more than twenty feet below the surface1 long before low water they would be found floating on the surface in full view4 ,many attempts have been made to overcome this difficulty1 but as yet no really practicable means have been devised4 #e4--,the stations where the firing batteries1 c41 are placed1 should be in the defensive work likely to be held the longest1 thus enabling the mines to be commanded up to the last moment4 #f4--,the electric cables should be laid in positions such that their discovery by the enemy would be extremely difficult1 and almost impossible4 ,,note4--,this may be to a certain extent effected by leading them from the mines to the firing and observing stations by circuitous routes1 and by burying them in trenches4 #g4--,they should not be thrown away on boats4 ,,notes4--,as they can in all cases be fired by will1 even when circuit closers are used1 this rule is easily observed4 ,but to prevent an enemy's boats from rendering the mines useless1 a line of small torpedoes might be placed in advance of the large ones1 or the circuit closers themselves might be charged4 ,at night1 or in foggy weather it will be necessary to employ guard-boats1 electric lights1 c41 to protect them against damage by an enemy's boats1 c4 ,in the foregoing pages of this chapter will be found the requirements and conditions essential to a perfect system of electrical submarine mines for the defence of a harbour1 river1 c42 in the following pages a general description of the component parts of such defensive torpedoes1 under the following heads--,form and ,construction of ,case2 ,electrical ,fuzes2 ,electric ,cables2 ,watertight ,joints2 ,junction ,boxes2 and ,mode of ,mooring1 will be considered4 ,form and ,construction of ,torpedo ,case4--,the case of a submarine mine should be capable of fulfilling the following conditions3-- #a4 ,it must be able at great depths to withstand a great pressure of water1 and remain perfectly watertight4 ,,note4--,this in the case of a charge of gunpowder being an imperative necessity4 #b4 ,as a buoyant mine1 it must be capable of affording a considerable excess of buoyancy1 by which it may be rendered stationary when moored4 ,,note4--,this is generally obtained by having an air space within the torpedo1 thus requiring a much larger case in which the charge is enclosed than would otherwise be necessary1 causing increased difficulties in transportation1 mooring1 and raising them for examination1 c4 #c4 ,when explosive agents which require a certain time for thorough combustion are used as the charge1 such as gunpowder1 picric powder1 gun-cotton 7not fired by detonation71 c41 a much stronger case is necessary to obtain the full explosive effect than would be the case were detonated charges1 under the same conditions1 employed4 ,,note4--,this is an extremely important point1 for if a weak case is employed with a charge of gunpowder1 c41 fired by a fuze primed with powder only1 a portion of it on being fired would generate a sufficient quantity of gas to burst the case1 thus blowing out the remainder of the charge before its ignition had been effected4 #d4 ,it should be of such a form that the complete ignition of the charge is obtained by the employment of the least number of fuzes possible to effect this result4 ,,note4--,this point is especially to be observed when gunpowder is the explosive agent4 ,the various forms of defensive torpedo cases may be classed under the following heads3-- #a4--,spherical shape4 #b4--;,cylindrical shape4 #c4--;,conical shape4 ,spherical ,shape4--,this form of case is theoretically the very best one possible to devise1 but on account of the difficulty of constructing it1 and its comparative costliness1 such a form may be put aside as being impracticable4 ,cylindrical ,shape4--,torpedoists in general have hitherto adopted the cylindrical form of case as being the best adaptable for both ground and buoyant mines containing a heavy charge4 ,the ,confederates employed exclusively this shape for their electrical submarine mines1 which were ground ones1 and the ,austrians in the war of #ff approved of this form of case for their electrical submarine mines1 which were buoyant ones4 ,figs4 #ai and #bj represent respectively the ,american and ,austrian mines4 ,in ,england the cylindrical shape has up to quite lately found most favour with her torpedoists for both buoyant and ground mines4 ,at ,fig4 #ba is represented a #ajj-lb4 buoyant electrical mine1 surrounded by a wooden jacket1 e1 and having its circuit closer1 ,c1 enclosed within it2 and at ,fig4 #bb is shown a #bej-lb4 electrical mine1 which may be used either as a buoyant or ground one4 ,for large ground mines1 the best form of torpedo case seems to be that of the turtle mine1 which is shown at ,fig4 #i4 ,a heavy charge may be contained in it2 it forms its own anchor2 and it would withstand an explosion of an adjacent mine without sustaining any injury4 ,at present the cylindrical shape is the form generally used1 though as far as retaining its position on the ground in a strong tide1 it cannot be compared to the turtle form4 ,illustration3 ,,form ,,of ,,case ,,of ,,submarine ,,mines4 ,,plate ,,vi4 ,the ,conical ,shape4--,hitherto this shape of submarine mine case was only used in connection with mechanical mines1 but now it is the form considered most suitable for all buoyant mines1 electrical or mechanical4 ,at ,fig4 #bc is shown the conical shaped mechanical mine1 employed by the ,confederates for use with sensitive fuzes4 ,the conical form of torpedo case lately approved of by the ,english torpedo authorities is somewhat similar to that one1 the charge being contained in a kind of box hung from the top of the case1 and the circuit closer is screwed into the bottom of the case2 surrounding the upper part of the case is a thick buffer of wood1 by which damage to the mine is prevented by the passage of friendly ships4 ,this is altogether a very neat and serviceable form of torpedo case4 ,this form of case is also more difficult to discover by dragging1 and easier to retain in position4 ,electrical ,fuzes4--,the fuzes employed in connection with electrical submarine mines may be divided into two classes3-- #a4 ,platinum wire bridge fuzes4 ,,note4--,that is where the evolution of heat is caused by a large quantity of the electric force flowing through a good conductor of large section1 such as the copper core of electric cables1 being suddenly checked by a very thin wire composed of a metal which compared with the conductor offers a very great resistance1 such as platinum4 #b4 ,high tension fuzes4 ,,note4--,that is where the evolution of heat is caused by the electric spark1 or by the electric discharge taking place through a substance which offers very great resistance to the passage of the electric force4 ,platinum ,wire ,fuze4--,this is the form of electrical fuze most commonly used1 and which will most certainly supersede altogether the high tension fuze4 ,there are numerous advantages accruing from the use of platinum wire fuzes1 the chief of which are here enumerated3-- a4--,great facilities for1 and entire safety whilst testing the circuit4 b4--,extreme simplicity of manufacture4 c4--,non-liability to deteriorate4 d4--,perfect insulation of the electric cables used in connection with submarine mines not necessary4 ,english ,service ,platinum ,wire ,fuze4--,the following is a description of the platinum wire fuze of the form adopted in the ,english service1 a section of which is shown at ,fig4 #bd4 ,it consists of a head of ebonite a1 hollowed out1 in which a metal mould is fixed1 the wires which have been previously bared are inserted into holes in this mould1 and firmly fixed thereto by means of a composition poured into the mould1 whilst hot2 this is shown at b4 ,the two bared ends of the wires which project beyond the metal mould1 as c1 c1 are connected by a bridge of platinum-silver wire #jjad in diameter and weighing #ba grs4 per yard4 ,this is effected as follows3-- ,a very fine shallow groove is made in the flat ends of the bare wires c1 c1 and the platinum-silver wire is laid across in the incisions1 and fixed there by means of solder4 ,the length of the bridge d is #be4 ,a tube e1 made of tin1 and soldered to a brass socket f1 is fixed by means of cement to the ebonite head a2 in this tube is placed the fulminate of mercury1 the open end of the tube g being closed with a pellet of red lead and shellac varnish2 around the bridge of the fuze is placed some loose gun-cotton4 ,mc,evoy's ,platinum ,wire ,fuze4--,another form of platinum wire fuze1 which has been devised by ,captain ,mc,evoy1 formerly of the ,confederate ,service1 is shown at ,fig4 #be4 ,it consists of the head a1 formed of a mixture of ground glass1 or ,portland cement1 worked up with sulphur as a base3 this mixture when hot is poured into a mould1 in which the two insulated copper wires1 b1 b1 have been previously placed2 when cold1 the mixture with the wires affixed is removed from the mould1 and the platinum wire bridge c being secured to the bare ends of the copper wires1 the whole is firmly fixed in a brass socket d1 by means of cement2 the space e is filled with loose dry gun-cotton1 so as to surround the bridge c2 a copper tube f1 closed at one end1 is partly filled with fulminate of mercury1 and when the fuze is required for service1 this tube is secured to the brass socket d by means of cement4 ,in this form of low tension fuze there is no liability whatever of any injury being caused to the bridge by the working of the wires in the head1 or by damp even after lying in the water for a month or more4 ,one peculiarity of this fuze is that the composition is run over the insulated wires without materially softening the dielectric1 or affecting in the slightest degree the insulation of the wires4 ,high ,tension ,fuzes4--,the high tension fuze was devised for use with electrical submarine mines1 in the place of the platinum wire fuze1 on account of the little knowledge possessed1 in the early days of submarine warfare1 in regard to the manipulation of ,voltaic batteries4 ,platinum wire requires a temperature of some #ejj ,f4 to heat it to incandescence1 and therefore necessitates the use of a powerful ,voltaic battery1 both in intensity and power1 to effect the ignition of gunpowder by this means at considerable distances4 ,the ,grove and ,bunsen pile were the only suitable form of ,voltaic battery known at the period of the introduction of high tension fuzes1 both of which possessed the defects of uncertainty and inconstancy1 and also were by far too cumbersome and too difficult to keep in effective working order to be of any real practicable value4 ,high tension fuzes may be ignited by means of either an electro-magneto machine1 an electro-dynamo machine1 a frictional machine1 or by a ,voltaic battery1 generating an electric current of high intensity4 ,various kinds of this form of electrical fuze have been designed1 the principal of which are as follows3-- #a4--,statham's fuze4 #b4--;,beardslee's fuze4 #c4--,von ,ebner's fuze4 #d4--;,abel's fuze4 #e4--;,extempore fuze4 ,statham's ,fuze4--,a section and elevation of this electric fuze are shown at ,fig4 #bf2 a1 b is a gutta percha tube1 with an opening cut in it1 as shown in figure4 ,the interior of this vulcanised gutta percha tube is coated with a thin layer of sulphide of copper1 which coating is obtained by leaving a bare copper wire for some time in connection with the above-mentioned tube4 ,the extremities of two insulated copper wires c1 c1 considerably smaller than the conducting wires1 are uncovered1 scraped1 and then inserted into the tube a1 b1 with an interval of #ae inch between them4 ,the wires are then bent as shown in the figure1 and the priming placed between the terminals4 ,the whole is covered with a gutta percha bag1 which is filled with fine grained gunpowder4 ,the priming substance is composed of fulminate of mercury worked up with gum water4 ,the objection to this fuze1 which was used by the ,allies in their destruction of the ,russian fortifications at ,sebastopol1 is the want of sensitiveness of sulphide of copper1 and the consequent necessity of a very powerful firing battery4 ,beardslee's ,fuze4--,this high tension fuze is shown at ,fig4 #bg4 ,it consists of a cylindrical piece of soft wood a1 which is about three-quarters of an inch in length and in diameter2 two copper nails1 b1 b1 are driven through this piece of wood a1 in such a way that while the two heads come together as close as possible without absolutely touching1 the pointed ends are some distance apart from each other1 and project through the wood a2 two insulated copper wires1 c1 c1 are firmly soldered to these projecting ends1 and a piece of soft wax1 d1 is pressed around the junction points4 ,in a groove1 across the heads of the copper nails1 is placed a little black lead1 to which is added a minute quantity of some substance1 the nature of which is known only to ,mr4 ,beardslee4 ,several folds of paper are wrapped round the wooden cylinder1 forming a cylinder about #b-a_/b inches long1 one end of which is tightly fastened round the insulated wires as at e4 ,the other end of the cylinder is then filled with powder1 f1 and closed by a piece of twine4 ,the whole fuze is then coated with black varnish4 ,though not highly sensitive1 ,beardslee's fuze is exceedingly efficient1 and extremely simple4 ,von ,ebner's ,fuze4--,this form of fuze was devised by ,colonel ,von ,ebner of the ,austrian ,engineers4 ,a section and elevation of it is shown at ,fig4 #bh4 ,it consists of an outer cylinder1 a1 of gutta percha1 and an inner one of copper1 b1 which latter encloses a core formed of ground glass and sulphur1 c1 which core is cast round the two conducting wires d1 d in such a way that they are completely insulated from one another4 ,in the first instance the wire is in one continuous length1 the opening e being subsequently made1 and carefully gauged1 so as to ensure a uniform break1 or interval in the conductor of each fuze4 ,the priming composition1 which consists of equal parts of sulphide of antimony and chlorate of potash1 is placed in the hollow f1 to which is added some powdered plumbago1 for the purpose of increasing the conducting power of the composition4 ,this mixture is put into the hollow1 f1 of the fuze under considerable pressure1 the terminals being connected with a sensitive galvanometer1 in circuit with a test battery1 and the pressure applied so as to obtain1 as far as possible1 uniformity in the electrical resistance of each fuze4 ,the ,austrians employed this form of high tension fuze in connection with a frictional machine for the electrical mines used in their defence of ,venice1 c4 during the war of #ahff4 ,abel's ,fuze4--,mr4 ,abel devised a high tension fuze1 which in #aheh was extensively experimented with2 the ,beardslee and ,von ,ebner fuze being based upon the principles applied for the first time in ,abel's fuze4 ,illustration3 ,,electrical ,,fuzes4 ,,plate ,,vii ,many modifications of it have been from time to time devised by ,mr4 ,abel2 a section and elevation of the more recent form of his fuze is shown at ,fig4 #bi4 ,it consists of b1 b1 a body of beech wood1 hollowed for half its length1 in which space the priming charge is placed2 it is also perforated by three holes1 one vertical for the reception of the capsule of sensitive mixture1 the other two horizontal1 in which the conducting wires are placed2 a1 a are two insulated copper wires1 passing into the vertical hole1 and resting on the sensitive mixture2 in a cavity1 d1 of the body of the fuze is placed some mealed powder1 which is fired by the ignition of the sensitive mixture on the passage of the electrical current4 ,the insulated wires used in connection with this fuze consist of two copper wires1 about #b inches long1 and #jbb inch in diameter1 enclosed in a covering of gutta percha #ac inch in diameter1 and separated about #jf inch from each other4 ,at one end the wires are bared to #abe inch1 at the other they are merely cut across by a very sharp pair of scissors4 ,this end of the double covered wire is inserted into a paper cylinder c1 c1 which holds a small quantity of the priming mixture4 ,this capped end of the wires is inserted into the wooden body of the fuze through the vertical hole i1 and projects #ae inch into the cavity d4 ,the bare ends of the double covered wires are pressed into small grooves in the head of the cylinder e e1 and each extremity is bent into one of the small channels d' d'1 which are at right angles to the vertical perforation4 d' d' are two small copper tubes driven into these channels over the wire ends1 to keep the wires in position1 and to form the opening into which the conducting wires f are inserted and bent round1 as at e'4 ,the priming mixture of ,abel's original fuze1 which was the one used by the ,confederates1 was composed of #aj parts of subphosphide of copper1 #de parts of subsulphide of copper1 and #ae parts of chlorate of potash4 ,these ingredients reduced to a very fine state of division1 and intimately mixed1 in a mortar1 with the addition of a little alcohol1 are dried at a low temperature and preserved in bottles until required for use4 ,the sensitive mixture used by ,mr4 ,abel more recently for his submarine electrical high tension fuzes1 is composed of an intimate mixture of graphite and fulminate of mercury4 ,by the process of ramming1 the electrical resistance of the fuze is regulated4 ,extempore ,fuzes4--,it may be necessary in some cases1 when a specially manufactured fuze is not attainable1 to make a fuze on the spot4 ,the following is a neat and simple method of constructing an extempore high tension fuze4 ,fisher's ,extempore ,fuze4--,this form of fuze was devised by ,lieutenant now ,captain ,fisher1 ,r4,n4 ,it consists of a small disc of gutta percha1 through which the ends of two wires are inserted about #a_/d inch apart1 their ends terminating in small copper plates formed by hammering down the wire4 ,these flat ends should be fixed parallel1 and in the first place in contact with one another1 also should be level with the surface of the gutta percha4 ,the other two extremities of the wires are then placed in circuit with a sensitive galvanometer and a test battery2 the needle of the former deflects violently1 there being a complete metallic circuit2 the flat ends of the wires or poles of the fuze are then separated very carefully1 until the needle just ceases to deflect4 ,in the space thus formed1 a little scraped charcoal is placed1 and rammed in by a piece of wood4 ,by the application of pressure1 any degree of sensitiveness may be attained1 merely observing the deflection of the galvanometer needle4 ,over the charcoal a little powdered resin is shaken1 and pressed down1 by which means the charcoal is fixed in position1 and owing to the inflammability of the resin1 the ignition of the gunpowder priming is ensured4 ,the disc of gutta percha is then placed in an empty ,snider ball cartridge1 c41 and by the application of a little warm gutta percha applied externally1 the holes where the projecting ends of the wires pass are closed1 and the disc is fixed and insulated4 ,the case is then filled with some mealed powder and fine grained powder1 on the top of which is placed a little cotton wool1 and the whole pressed down tightly with the finger1 the open end of the case being then choked1 as in ,beardslee's fuze and ,abel's extempore one4 ,the apex is then covered with some warm gutta percha1 and the whole of the fuze coated over with red sealing-wax dissolved in methylated spirits4 ,insulated ,electric ,cables4--,for the work of defence by electrical submarine mines1 the wires along which the electric current flows have1 on account of their being led underground and through the water1 to be covered with some substance which shall prevent the current during its passage from escaping to earth1 or in other words1 they 7the wires7 must be insulated4 ,the substances in general use for such purposes are as follows3-- #a4--;,gutta percha4 #b4--,ordinary india rubber4 #c4--;,hooper's material4 ,gutta ,percha4--,this substance was used by ,messrs4 ,siemens in the cables manufactured by them for the ,austrian government in #ahff1 and is to some extent still employed1 though ,hooper's material or vulcanised india rubber1 has been found to be more suitable4 ,the dielectric1 gutta percha1 possesses the following advantages3-- a4--,it can be put on the conducting wire1 as an unbroken tube4 b4--,it only absorbs #a per cent4 of water4 c4--,it has the property of clinging to the metallic conductor1 by which is meant1 that should it 7conductor7 be cut through1 and any strain be brought on the cable1 there is a tendency on the part of the gutta percha to cling to the conducting wire1 thereby not increasing the fault4 ,the defects of such an insulator are3-- a4--,its liability to become hard and brittle when exposed to dry heat1 and consequently it requires to be stored under water4 b4--,it becomes comparatively a bad dielectric at #ajj ,f4 c4--,it becomes plastic at high temperatures1 which causes the conducting wire to alter its position4 ,in some particulars ordinary india rubber is a better insulator than gutta percha1 but this substance is equally inferior to ,hooper's material1 c4 ,the advantages possessed by this substance are3-- a4--,it is not easily affected by a dry heat4 b4--,it is a very excellent dielectric4 ,the defects of this mode of insulation are3-- a4--,it must be put on the conducting wires in a series of jointed pieces4 b4--,it does not cling to the conducting wire1 so that if the electric cable be cut1 and any strain be brought on it 7cable71 the previous fault is increased4 c4--,it absorbs #be per cent4 of water4 ,hooper's ,material4--,this insulating material consists of an inside coating of pure india rubber1 then another similar coating in conjunction with oxide of zinc1 which is termed the separator1 and an outside coating of india rubber combined with sulphur4 ,the use of the separator is to prevent any damage to the conducting wires by the action of the sulphur4 ,the three coatings are then baked for some hours at a very high temperature1 which fuses the whole into a solid mass1 and vulcanises the outer coating4 ,the properties of the pure india rubber which is in contact with the metallic conductor are thus preserved1 while any decay of the outer covering is prevented by the vulcanising process4 ,the advantages claimed by ,mr4 ,hooper for this mode of insulating electric submarine cables1 are3-- a4--,high insulation4 b4--,flexibility4 c4--,capability of withstanding the bad effects of dry heat4 ,the qualifications essential to a perfect insulated electrical cable for use with submarine mines are as follows3-- #a4--;,capacity to bear a certain amount of strain without breaking4 #b4--,perfect insulation1 or at least as nearly so as it is possible to obtain1 and composed of a substance capable of being readily stored1 and kept for a considerable length of time without being injured4 #c4--,pliability so that it may be wound on1 or paid out from1 a moderately sized drum without injury4 #d4--,provided with an external covering capable of protecting the dielectric from injury when used in situations where there is a rocky or shingly bottom1 c4 ,the insulated wire of a submarine cable is technically spoken of as its core4 ,by a cable is meant to be understood any piece of covered wire4 ,several forms of submarine electrical cables have been devised1 all of which more or less possess the qualifications enumerated above4 ,the following are some of the most effective3-- #a4--,siemens's cable4 #b4--;,hooper's cable4 #c4--;,gray's cable4 #d4--,service cable4 ,siemens's ,cable4--,this form of cable is represented at ,fig4 #cj4 ,it consists of a strand a1 which is composed of three or more copper wires formed by laying up the several single copper wires spirally1 several layers of gutta percha1 or india rubber1 b1 two coverings of hemp1 saturated with ,stockholm tar1 c and d1 and several plies of copper tape e1 wound on1 so that each strip overlaps the preceding one1 as shown at ,fig4 #cj4 ,the conductivity of the copper employed for the strand is equal to at least #ij per cent4 of that of pure copper4 ,this exterior covering of copper tape is a patent of ,messrs4 ,siemens ,brothers1 and when once laid down1 the cable so covered is very efficiently protected1 and of course it is little affected by the action of the sea water4 ,this mode of protection has one great defect1 viz41 that in the event of a kink occurring in paying out the line1 and at the same time a sharp strain being applied1 the copper tape at that point is extremely likely to destroy the insulation by being drawn in such a way as to cut through the dielectric4 ,on this account great care must be observed in handling this form of cable4 ,in practice precautions must be taken to prevent the copper tape covering from being brought into contact with any iron1 for were such to happen1 electrical action would at once ensue1 causing the iron to corrode with enormous rapidity4 ,in some of ,siemens's cables1 vulcanised india rubber replaces the gutta percha insulation4 ,iron covered cables1 either galvanised or plain1 are manufactured as well as the copper tape covered ones by that firm4 ,hooper's ,cable4--,this form of cable is represented at ,fig4 #ca4 ,it consists of a metal conducting wire1 generally copper1 a1 covered with an alloy to protect it from chemical action1 the insulating substance b1 known as ,hooper's material1 previously described at page #ci1 a covering of tarred hemp c1 and an outer covering of iron wires 7,no4 #aa ,b4 ,w4 ,g471 each of which is separately covered with tarred hemp and wound on spirally1 d4 ,gray's cable is very similar to the one just described1 the chief difference in it as compared with ,hooper's being the absence of the separator4 ,silvertown ,cables4--,the following is a description of the core of an electrical submarine cable1 which is used by the ,english government1 and is supposed to contain all the advantages of the foregoing1 and none of their defects4 ,it consists of a strand conductor of four copper wires 7,no4 #bj ,b4 ,w4 ,g47 of quality not less than #ib per cent4 of pure copper1 and possessing an electrical resistance of not more than #ad ohms per nautical mile4 ,this strand is tinned and insulated with vulcanised india rubber to a diameter of #bd inch1 and then covered with a layer of felt1 and the whole subjected to a temperature of #cjj ,f4 under steam pressure4 ,this forms the core of the various kinds of cables employed in connection with a system of defence by electrical submarine mines1 which are enumerated as follows3-- #a4--,single core armoured cable4 #b4--,multiple cable4 #c4--;,circuit closer cable4 #d4--,single core unarmoured cable4 #e4--,special cables for firing by cross bearings4 ,single ,core ,armoured ,cable4--,this form of cable is used in connection with each mine of a group or system1 and also to connect forts1 c4 across an arm of the sea4 ,over the core1 which has been fully described1 is laid a spiral covering of tanned1 picked ,russian hemp1 over this are laid ten galvanised iron wires 7,no4 #ac ,b4 ,w4 ,g471 each one of which is covered with a similar hemp1 which is laid in an opposite spiral to the former similar covering1 with a twist of one revolution in about thirteen inches2 in order to prevent these wires from gaping when the cable is kinked1 a further covering of two servings of hemp passed spirally in opposite directions is laid1 and the whole passed through a hot composition of a tar and pitch mixture4 ,exterior diameter of this cable is #g_/h inch4 ,its weight in air is #bg-ej_/aab cwt41 and in water #ad-dj_/aab cwt4 per nautical mile4 ,the breaking strain of a cable thus manufactured is #fb-a_/b cwt41 and its cost about #dg per nautical mile4 ,a diagram of this cable is shown at ,fig4 #cb4 ,multiple ,cable4--,this form of cable is employed in cases where it is necessary to carry a large number of cables into the firing station1 c4 ,it consists of seven single cores formed into a strand1 over which a padding of hemp fibres is laid longitudinally1 and over this again is laid an armouring of sixteen 7,no4 #i ,b4 ,w4 ,g47 galvanised iron wires1 each one of which is covered with a layer of tarred tape put on spirally with a twist of one revolution in #ae inches4 ,the exterior covering consists of two layers of hemp and composition1 which is laid on with a short twist1 and in opposite directions4 ,the external diameter of this cable is #a-a_/d inch4 ,its weight in air and water is #gh-be_/aab cwt41 and #de-cb_/aab cwt4 respectively per nautical mile4 ,its breaking strain is #ace cwt41 and cost about #ceg per nautical mile4 ,this form of cable is used in connection with a junction box1 from which the single armoured cables leading to the different mines radiate1 and is shown at ,fig4 #cc4 ,circuit ,closer ,cable4--,this cable1 which connects the mine and circuit closer1 has been found to be subjected to exceptional wear and tear1 and therefore requires a special form of exterior protection4 ,the core of this cable is the same as the one described at page #da1 also it is covered with a similar padding of hemp1 but instead of the iron wires as in the case of the multiple cable1 c41 nine strands1 each of which is composed of fourteen ,no4 #bb ,bessemer ,steel ,wires1 are wound on1 each such strand being covered with hemp1 which is put on with a twist of one revolution in every #g-a_/b inches1 the external covering being the same as in other cables4 ,this form of armouring for an electric cable possesses the qualifications of pliability1 lightness1 and great tensile strength4 ,its weight in air is #eb-ajf_/aab cwt41 and in water #bh-d_/aab cwt4 per nautical mile4 ,its breaking strain #fe cwt41 and cost about #abg per nautical mile4 ,single ,core ,unarmoured ,cable4--,this form of cable is used in a system of defence by submarine mines to connect the detached works of a maritime fortress1 c41 for the purpose of telegraphing4 ,it consists of the ordinary service core1 over which are laid two servings of tarred hemp1 put on spirally4 ,the weight of this cable in air is #d-ac_/aab cwt41 and in water #a-cf_/aab cwt4 per nautical mile2 its breaking strain is #g-a_/b cwt41 and its cost per nautical mile is about #ce4 ,special ,cables4--,in firing electrical submarine mines by means of cross bearings1 a special cable is employed4 ,as a general rule there would be three lines of mines placed to converge on one of the stations4 ,each of these lines would be provided with a conducting wire in connection with the firing arrangements1 while one line of wire in connection with the firing station would be required for telegraphing4 ,for the purpose in question a four cored cable is used4 ,land ,service ,cable4--,the cable employed for this service consists of a core formed similar to that of the multiple cable1 described at page #da2 over which is laid a padding of hemp1 and finally two servings of tarred hemp laid spirally in opposite directions are wound on4 ,its weight in air is #af cwt41 and in water #d-ej_/aab cwt4 per nautical mile4 ,its breaking strain #ag-a_/b cwt41 and cost per nautical mile about #acg4 ,sea ,service ,cable4--,this consists of a similar core to the land service cable1 and padding of hemp1 over which is laid an armouring of fifteen ,no4 #ac galvanised iron wires1 each one being covered with tarred tape1 and finally the ordinary servings of tarred hemp4 ,its weight in air is #di-aja_/aab cwt41 and in water #be-aji_/aab cwt4 per nautical mile4 ,its breaking strain #fe-ajj_/aab cwt41 and cost per nautical mile about #bjb4 ,when frictional electricity is used to fire high tension fuzes1 it has been found by experiment that if several lines of insulated cables are laid in the same trench for a few hundred yards1 the inductive effect of the electrical charge generated by a frictional machine is so great that its discharge through one cable is sufficient not only to fire the fuze in immediate connection with it1 but by induction every other fuze in connection with the remaining wires laid in the trench4 ,and this effect equally occurs when the electric cables are some feet apart1 provided they run parallel for a few hundred yards1 and whether the shore ends of the cables1 the fuzes in connection with which are not intended to be fired1 are insulated1 or put directly to earth1 the connections beyond the fuzes being to earth1 or even insulated1 provided a very few yards of conductor exist beyond the fuze4 ,the length of wire which it is necessary to use between the mine and its circuit closer would be quite sufficient for the purpose of effecting ignition by induction4 ,with platinum wire fuses there is no danger whatever of the above happening1 nor in the case of high tension fuzes is there so much danger of ignition by induction1 when a constant instead of a frictional electric battery is used to generate the current4 ,another mode of protecting an insulated cable is to place it1 as it were1 in the core of a hempen cable4 ,in forming the rope on the cable1 great care is necessary to prevent any serious amount of torsion1 or tension coming on the insulated wire1 either of which would most assuredly result in injury to the cable4 ,this form of cable might in connection with obstructions1 c41 be of great use1 as on account of its closely resembling an ordinary rope1 it would be very unlikely to excite suspicion1 and so would most probably be cut1 the result of which1 by previous arrangement1 would be an explosion of a mine1 or by means of a galvanometer1 c41 an indication that the obstructions1 c41 were being interfered with4 ,jointing ,electrical ,cables4--,this is a very important point in connection with a system of defence or offence by electrical torpedoes4 ,in many instances it will be found necessary to join either two lengths of cable1 or an insulated wire and a cable1 together1 in both of which cases1 great care must be used in making the joints1 so that the insulation and the continuity of the circuit may be perfect4 ,illustration3 ,,electric ,,cables1 ,,extempore ,,cable ,,joints4 ,,plate ,,viii ,many species of junctions have been from time to time devised1 the most practical and generally employed of which are3-- #a4--;,india rubber tube joint4 #b4--,mathieson's joint4 #c4--;,beardslee's joint4 #d4--,mc,evoy's joint4 #e4--,permanent junction4 ,india rubber ,tube ,joint4--,this form of joint is a very useful one for extempore purposes1 being easily and quickly made1 and being very effective4 ,at ,fig4 #cd is shown a sketch of such a junction4 ,about #ae inches of the copper conductor of the two insulated cables are laid bare and connected together by means of ,nicoll's metallic joint1 as shown at ,fig4 #cf1 or by turning one of the conductors round the other1 their ends being carefully pressed down by means of pliers1 to prevent any chance of the india rubber tube being pierced2 over the splice thus formed serve some twine1 and over the whole put a coating of india rubber cement1 grease1 c41 then draw the vulcanised india rubber tube1 which has been previously placed on one of the insulated cables1 over the splice a1 as shown at b1 and secure it firmly by means of twine1 c1 c1 and then to prevent any strain being brought on the joint1 form a half-crown as shown in ,fig4 #ce at ,a4 ,in forming the splice1 it is very important that the metallic ends should be perfectly clean4 ,the danger to this mode of jointing of the piercing of the tube by the ends of the conductors is entirely removed by employing the ,nicoll metallic joint1 which is formed as follows3-- ,nicoll ,metallic ,joint4--,one of the conducting wires1 as a1 ,fig4 #cf1 is formed into a spiral twist by means of a very simple instrument1 and the other wire b1 which is left straight1 is inserted into the spiral1 the whole being placed on an anvil1 and pressed closely and securely together by a single blow of a hammer4 ,mathieson's ,joint4--,this somewhat complicated1 though very effective mode of jointing1 which is adopted in the ,english torpedo service1 is shown at ,fig4 #cg1 in elevation and section4 ,it consists of two ebonite cylinders a1 a1 through which the cables to be connected are passed4 ,within these cylinders an ebonite tube b1 b is placed1 the ends of which are wedge-shaped1 and which press against two vulcanite rings c1 c2 in the interior of this tube b1 b is the metallic joint d of the two cables4 ,the centre of the tube b1 b is of square section1 and fits into a hollow of similar form in the cylinders a1 a1 the object of this being to prevent any twisting of the wires during the process of screwing up1 which would be liable to injure the metallic joint d4 ,the manner of making this joint will be easily understood from the figure4 ,with this1 as with all other temporary joints1 it is advisable to form a half-crown in the cable1 including the joint4 ,beardslee's ,joint4--,this form of temporary joint when used with strand conductors1 which are composed of a number of small wires1 has been found to be exceedingly useful and effective1 the only defect of such a joint being the liability of straightening the wires of the conductors should a direct strain be brought upon the wire extremities4 ,fig4 #ch represents a section of this joint2 it consists of an ebonite cylinder a1 one end of which is solid1 and the other open and fitted with a screw thread1 into which is screwed a plug b2 through both the plug b1 and the solid end of the cylinder a1 perforations are made just large enough to admit the insulated wires c1 c2 about half an inch of the extremities of these wires are bared and cleaned1 and then passed1 the one through the plug b1 a disc of vulcanised india rubber d1 and a metal disc e1 and the end of the strand conductor turned back on the face of this metal disc1 the other through the perforation in the solid end of the cylinder a1 then through similar discs d and e1 and the end of the strand conductor treated in the same manner as the former one2 then by means of the screw plug b1 the two metallic discs b1 b1 and consequently the bare extremities of the strand conductors are brought into close metallic contact4 ,mc,evoy's ,joint for ,iron ,wire covered ,cable4--,this form of joint is shown in section at ,fig4 #ci4 ,two brass caps a1 a are slipped over the ends of the cables required to be joined1 then the iron wire and other coverings of the cables down to the insulating substance are removed1 the former being bent back close against the bottom of the caps a1 a1 as shown in ,fig4 #ci at b1 b2 the cores of the cables are then joined by an india rubber temporary joint c1 which has been described at page #de3 the whole is then placed in the body of the joint1 and the brass caps a1 a screwed up1 jamming the bent back iron wires against a solid piece of brass d1 d1 by which means a firm and perfect joint is made in the cables4 ,illustration3 ,,permanent ,,joints ,,for ,,electric ,,cables4 ,,plate ,,ix ,fig4 #dj represents a section of a ,mc,evoy temporary joint for single cored unarmoured cables1 which seems to fulfil all the conditions necessary to a perfect joint of that description4 ,this joint is1 with the exception of there being two screw plugs instead of one1 very similar to ,beardslee's joint described at page #df2 this alteration is a great improvement1 remedying as it does the one defect of ,beardslee's joint1 viz41 the liability of the cables to be drawn apart due to any great tension being brought on them4 ,a permanent joint in electrical submarine cables1 which from its nature requires to be an exceptionally good one1 is a somewhat difficult and troublesome operation1 and also requires a considerable time to form a thoroughly reliable one4 ,siemens's ,methods of ,jointing4--,the following methods1 and instructions for forming such joints1 are those adopted by ,messrs4 ,siemens ,brothers in connection with their telegraph cables1 and which will be found generally applicable to all insulated cables4 ,the ,formation of a ,joint in the ,conductor of an ,insulated ,cable4--,the conductor is either covered with a gutta percha or an india rubber dielectric4 ,in both cases cut off the dielectric so as to bare the conductor-wire for a length of about three inches1 taking care never to cut at right angles to the conductor-wire1 for fear of injuring it with the cutting-knife or scissors4 ,then clean the wires forming the strand with file-card and emery-paper1 and solder them into a solid bar for a length of about one inch4 ,having soldered the wires1 forming the ends of the two lengths of conductors to be joined1 into two solid rods1 file each of them off in a slanting manner1 so that they will form a scarf-joint when put together4 ,place the two ends of strand in the two small vices on a stand which is supplied for the purpose1 so that the two scarfed ends overlap each other1 and bind them round with a piece of fine black iron wire1 in the shape of a spiral1 so as to keep the ends close together1 then solder the two ends together by applying a hot soldering iron4 ,then remove the iron binding wire and clean up the joint1 filing off all unnecessary solder4 ,and make a band of four fine tinned copper wires1 and bind them tightly side by side round the joint1 covering the whole length of the scarf1 and then solder the band and joint solidly together4 ,then make another band of four fine tinned copper wires and bind them round the joint in the same manner as before1 but extending about a quarter of an inch beyond each end of the other binding wire1 the parts only of this second binding which project beyond the end of the first binding are to be soldered1 so that the centre part remains loose and may keep up a connection between the two ends by forming a spiral between them in the event of the scarf giving way and the two ends of the conductor separating slightly4 ,this form of joint is called the spring joint4 ,the finished joint should be washed with spirit of wine and brushed1 so as to take away all particles of soldering flux1 and to avoid oxidation of the wire4 ,the washed joint should then be dried with a piece of cloth and exposed to the flame of a spirit lamp to dry it thoroughly4 ,a cable conductor ought never to be jointed with the help of soldering acid1 but with that of resin1 sal ammoniac1 or borax only1 so that any chance oxidation1 and consequently destruction1 of the conducting wire may be avoided4 ,there are other modes of jointing conductors1 such as the twisting and scale joint1 but the foregoing method will sufficiently explain this part of electric cable work4 ,the ,formation of a ,joint in an ,india rubber ,insulated ,cable4--,in making a joint in any insulated cable1 the very greatest care must be taken to keep the hands1 tools1 and materials clean and dry4 ,remove the felt for about twelve inches from each end of the core by soaking it with mineral naphtha and then rubbing it off clean with the file-card4 ,the cleaned surface sear with a red-hot iron1 to burn off all remaining fibres of the felt4 ,wash these seared ends clean with naphtha4 ,then cut off about four inches of the insulating material 7taking care never to cut at right angles to the conducting wire for fear of injuring it7 so as to leave enough of the conductor bare to join and solder in the manner described at page #dg4 ,after the conductor is jointed and soldered1 clean again the seared parts of the insulator with the glazed side of the squares of cloth moistened with mineral naphtha1 so as to leave a clean adhesiveness only2 taper again the insulating material down to the conductor for about two inches on each side of the conductor-joint with a pair of curved and very clean scissors4 ,the tapering must be completed in such slanting way that the different layers of the dielectric are so far exposed as to enable a secure laying on of the new jointing material4 ,india rubber core consists chiefly of three layers of insulating material3 the first layer next to the strand is called the pure or brown2 the second layer is the white or separating2 the third layer is the light red or jacket rubber4 ,coat the conductor with a pure 7brown7 rubber tape tightly laid on in a spiral form1 commencing at the spot where the separator 7white7 ends1 across the corresponding place on the opposite side of the joint and back again in a contrary direction4 ,the ends are fastened down by pressing a clean1 heated searing-iron or a heated knife on them4 ,by doing so the band will stick2 the remaining portions of the band to be cut off with the scissors4 ,lay on tightly the separating india rubber tape in the same manner1 but beginning where the jacket or outer layer of rubber ends4 ,one lap will be sufficient4 ,complete the insulation by lapping on tightly two layers of red india rubber tape3 the last lap must cover each end of the core to four inches on each side of the conductor-joint1 or extend to the searing or tackiness1 but not beyond it4 ,lay on three tight bindings of the cloth tapes1 all in the same direction1 care being taken to avoid wrinkles4 ,the ends of the cloth tapes are cemented down with a thin coating of india rubber cement4 ,immerse the joint in the jointing-bath at #aej to #bjj ,f4 and gradually raise the heat so that in half an hour the temperature will be #cbj ,f41 at which temperature keep the joint for twenty minutes3 then take it out and let it cool in the open air4 ,the ,formation of a ,joint in a ,gutta percha ,insulated ,cable4--,having jointed the conducting wires in the manner described at page #dg1 clean and dry the joint well and cover the bare conductor with a thin layer of compound4 ,this is best done by heating a small stick of compound to nearly its melting point1 and rubbing it over the bare conductor1 which has been previously heated with the flame of a spirit-lamp4 ,heat the gutta percha covering of both ends gently until it is quite soft1 without1 however1 causing it to bubble or burn4 ,draw1 then1 with the fingers1 the gutta percha coverings of both ends down1 tapering them off until they meet in the middle of the joint2 heat them sufficiently to make them adhere together4 ,apply a layer of compound on the tapered-off gutta percha in the same manner as described for coating the bare conductor1 and cover it with a first coating of gutta percha sheet to about half the thickness necessary to finish the joint4 ,this is done by heating a small sheet of gutta percha1 of about one-eighth of an inch in thickness1 until it is quite soft1 and by pressing it in that state round the joint to the required size2 the greatest care to be taken to expel all the air4 ,the projecting lips are then cut off with a pair of curved scissors4 ,the seam thus produced is to be rubbed with a hot iron until it is completely closed and the joint well rounded off4 ,apply another layer of compound and a second layer of gutta percha in exactly the same manner as described for the first layer2 care1 however1 is to be taken to get the seam in this second layer of gutta percha not over1 but as nearly as possible right opposite to1 the seam in the layer underneath4 ,the whole to be worked as cylindrical as possible1 and to a size not exceeding the original core4 ,the joint1 so far finished1 is then to be cooled with water until the gutta percha is quite consolidated4 ,another1 the overlapping gutta percha joint1 is made in the following manner3-- ,cut off the two ends of the core1 so that the gutta percha and the conductor-wire are flush4 ,warm the gutta percha for a distance of about three inches from each of the ends with the flame of a spirit lamp1 and1 when sufficiently soft1 push it back until it forms an enlargement4 ,the two ends of the conductor are then to be soldered according to instructions for making joint in conductors4 ,to have a perfectly clean surface of the two gutta percha enlargements1 remove all impurities by the way of peeling them with a sharp knife4 ,warm gently both knobs and the copper joint1 and cover the whole length of the bare wire with compound1 planing it with a warm smoothing-iron4 ,draw then with the fingers one of the warmed and softened knobs carefully up to the other knob or enlargement1 leaving on its way a perfect tube of gutta percha upon the wire1 decreasing gradually to the thickness of the copper strand towards the other knob4 ,any superfluous gutta percha is removed4 ,this scarf is finished with a warm smoothing-iron1 so as to unite it to the compound on the wire strand1 and a thin layer of compound is also put over the scarf in the same manner as before4 ,the other knob is then warmed and drawn in the same way over the tube already formed1 which is at the same time heated sufficiently to make the two adhere4 ,apply a layer of compound on the second scarf of gutta percha1 covering it in the same manner as described for coating the bare conductor1 and cover it with a small sheet of gutta percha in the same manner as described above1 so as to make the finished joint to the size of the core as manufactured4 ,rules to be observed in forming ,joints4--,the following rules must be carefully observed in forming either a temporary or permanent joint3-- #a4--;,in laying bare the conductor1 the dielectric should be warmed and then pulled off1 so preventing any chance of it being damaged1 which might be the case were the dielectric to be cut off4 #b4--;,for a perfect junction1 soldering is necessary4 #c4--,the wires before connection should be carefully cleaned1 and the hands of those performing the work must be dry4 #d4--;,gutta percha should not be given too much heat1 for it then becomes oily and will not1 in that state1 properly adhere4 #e4--;,grease and dirt must be scrupulously avoided4 ,great care is absolutely necessary in making junctions1 as they are the principal sources of defect in the insulation of electrical submarine cables4 ,junction ,boxes4--,when it is necessary to employ a multiple cable1 a junction box is used to facilitate the connection of the several separate wires diverging from the extremities of such a cable4 ,in one angle of such a box the multiple cable is introduced1 while the separate cables make their exit on the opposite sides and pass to the different mines4 ,different views of a junction box are shown at ,fig4 #da1 where ,a is a plan of the top or lid1 ,b a plan of the bottom1 with the lid off1 ,c an elevation1 and ,d a section of the box4 ,the manner of using the junction box is as follows3-- ,the multiple cable is put in at a1 and secured there by means of a nipping hook1 shown at ,fig4 #db1 which hook passes through the bottom of the junction and is made secure by means of a nut4 ,the single core cables radiating from the junction box pass through the openings b1 b1 b on the sides1 and angle opposite to where the multiple cable a enters4 ,each multiple cable is composed of seven cores1 and each of these is connected by means of joints with the mine cables within the junction box1 and each of these seven cables is secured by means of a nipper similar to1 but smaller than1 the one shown at ,fig4 #db1 which are also secured by means of nuts1 as in the case of the multiple cable nipping hook4 ,when all the connections are made1 the lid ,a is placed so as to rest on the studs c1 c1 c1 and firmly secured by a bolt d1 which is made water-tight by means of a washer and nut4 ,by means of the nipping hooks1 which take any strain that may be brought on the cables1 the connections within the box are ensured against injury by such a cause4 ,to enable the whole to be lifted together for the purposes of examination of the cables1 c41 a buoyed rope is connected to the eye-bolt e4 ,for this service a dummy circuit closer is the best form of buoy1 it having great buoyancy and resembling in appearance an active circuit closer4 ,a junction box should be placed in such a position as to be easily attained1 even in the presence of an enemy1 and its buoy should1 if possible1 not be seen4 ,it is also very essential that it should be in a safe and guarded position1 for any injury to the junction box or multiple cable would be fatal to the group of mines in connection4 ,in the following cases1 special junction boxes are used3-- #a4--;,a seven cored armoured cable to be connected direct to another length of the same4 #b4--;,a single armoured cable to be connected as in foregoing instance4 #c4--;,a ,t junction box for the branch system of electrical contact mines4 ,junction ,box for ,multiple ,cables4--,at ,fig4 #dc is represented a plan of lower half of this form of junction box4 ,it consists of a pair of cast iron plates of precisely similar form to the one shown at ,fig4 #dc1 and so made as to be capable of being fastened tightly together by means of four bolts and nuts passing through the holes a1 a4 ,the grooves b1 b at the two extremities are just large enough to grip the armoured cable firmly1 when the upper and lower parts are screwed together4 ,a larger space is provided in the hollow for the joint4 ,junction ,box for ,single ,cored ,cables4--,for this purpose a junction box similar to1 but smaller than the one above described is employed4 ,t ,junction ,box4--,this form of junction box is employed when the system of electrical contact mines on branches from a single cable is used4 ,this system is dependent on the use of a platinum wire fuze in connection with a platinum wire bridge in each branch close to its junction with the main cable4 ,this form of junction box1 which is shown at ,fig4 #dd is very similar to the one used for the connection of two multiple cables1 only differing in its shape1 which is that of a ,t4 a is a disconnector1 which will be described further on2 b1 b1 b' are the armoured electric cables1 b1 b being the main1 and b' the branch cable in connection with the forked joint formed within the ,t junction box2 c1 c1 c are ,turk's heads formed to prevent any strain being brought on the forked joint4 ,this form of ,turk's head is made by turning back the wires of the cable armouring1 and frapping them round with spun yarn until the necessary size and shape is attained4 ,mc,evoy's ,turk's ,head4--,another form of ,turk's head1 devised by ,captain ,mc,evoy1 is shown at ,fig4 #de4 ,it consists of two separate pieces of brass1 a and b1 the former screwing over the latter4 ,the mode of using it is as follows3-- ,slip the piece of brass b over the cable c1 and turn back the wires of the cable d1 d1 c41 so that they lie against the shoulder of the brass piece b1 then slip the other piece of brass a over the cable and screw it on the piece b1 firmly jamming the turned back wires d1 d1 c4 ,this is a very neat and quick method of forming a ,turk's head1 and it should be invariably used in preference to the foregoing method1 which is clumsy1 and which takes some time to form4 ,the section of a disconnector is shown at ,fig4 #df4 ,it consists of an iron cover1 or dome a1 which is provided with a screw fitting on to another screw on the ebonite body b of the apparatus4 ,when the dome a is screwed tightly down on the washer i1 the whole is made perfectly watertight4 c1 c are insulated terminals for connecting the cores of the branch and main cables after their armouring has been removed1 as shown at ,fig4 #dd4 d1 d are two copper conducting wires 7,no4 #af ,b4 ,w4 ,g47 passing through the centre of the ebonite body b1 and projecting into the interior of the apparatus4 ,these wires are held in position and insulated by means of a composition formed of a mixture of pitch1 tallow1 beeswax and gutta percha4 ,this composition is put on whilst hot and allowed to cool gradually1 when it becomes hard and durable4 ,great care is necessary to ensure the cavity within the ebonite body b being completely filled1 as otherwise a leakage might occur1 owing to the great pressure of water at depths where the disconnection would be generally used4 f is a boxwood cover which is slipped on1 and fits fairly tight to the ebonite body b2 g is a piece of thin platinum wire1 weighing #af grains to the yard1 and being #d_/aj inch in length2 h is an ebonite pin1 which passes through two small holes in the boxwood cover f1 into which it fits tightly1 and in such a position as to be directly beneath the platinum wire bridge g1 when the boxwood cover f is fixed on4 ,the pin h is pushed through the holes in the cover f from the outside1 so as to pass beneath the bridge g after the priming has been inserted1 and the cover has been placed on4 ,when prepared for use1 the platinum wire bridge g is surrounded by some loose gun-cotton priming1 sufficient in quantity to blow off the boxwood cover f1 without destroying the dome a2 the cover f being blown off1 carries the ebonite pin h with it1 and through the platinum wire bridge g1 thereby rupturing it1 and breaking the continuity of the circuit4 ,the object of so doing is to cut off the connection of an exploded mine1 so that the full amount of the firing current is available for the other mines1 and not suffered to be wasted by passing through the exposed wire of the broken circuit1 which1 were the disconnector not employed1 would be the case4 ,when any particular mine of a system is struck1 the current passes through the main cable b1 the disconnector a 7which is in connection with that mine71 and branch cable b' to the fuze1 and so explodes the mine1 and destroys the platinum wire bridge g of the disconnector at practically the same instant4 ,the effect of the latter operation would be to cut off and insulate the branch cable of the exploded mine1 and so prevent any loss of the electrical current1 when another mine of that system is required to be fired4 ,the platinum wire bridge g is #d_/aj inch long1 while that of the fuze is #c_/aj inch1 the object of this difference in length of the bridges being to ensure the former one g being fired1 and thus the insulation made doubly sure4 ,many other forms of disconnectors have been devised1 but none have proved in practice so effective as the one just described4 ,illustration3 ,,junction ,,boxes4 ,,mechanical ,,turk',s ,,head4 ,,plate ,x ,mooring ,electrical ,submarine ,mines4--,this is one of the most difficult problems to be solved in connection with a system of submarine mines4 ,the objects to be attained in mooring are as follows3-- #a4--,the mines should preserve the exact positions in which they are laid down4 ,,note4--,from the comparatively small radius of destructive effect1 of even heavily charged submarine mines1 it will be understood how absolutely essential1 in the case of mines fired by judgment1 it is that this object should be attained4 #b4--,the mooring chains1 or ropes1 must be so arranged that no twisting whatever should occur1 as otherwise fracture of the insulated wire would be likely to happen4 #c4--;,in the case of buoyant mines1 their distance from the bottom must be so adjusted1 that at no time shall a vessel passing over them be out of their vertical range of destruction1 nor shall they be visible4 ,the difficulties attendant upon the efficient mooring of submarine mines are immense1 as will be understood when the action of gales of wind1 and strong tides1 which latter vary continually in their direction and in their rise and fall1 are taken into consideration4 ,the foregoing remarks apply more particularly to a system of buoyant submarine mines1 as those placed on the ground are comparatively easy to moor4 ,several modes of mooring buoyant submarine mines have been suggested1 the most practicable of which are as follows3-- #a4--,ladder moorings4 #b4--;,fore and aft moorings4 #c4--;,austrian method of mooring4 #d4--,single rope mooring4 ,ladder ,mooring4--,this is a method of mooring1 which in places where it may be necessary to place the anchors far apart will be found useful4 ,the circuit closer is connected to the mine by two ropes which lead thence to two anchors1 the ropes being separated by wooden rounds1 or spreaders1 #a to #c feet long1 by which the tendency to twisting is prevented4 ,the anchors are placed some #ab feet apart4 ,the only defect of the ladder mooring is the quantity of sea-weed1 c41 that is liable to be lodged on the rounds1 thus causing the circuit closer to be drawn out of its proper position4 ,fore and aft ,mooring4--,this mode may be advantageously employed in a tideway where the current runs very strong1 that is to say1 five knots per hour1 or more4 ,it consists simply of two anchors1 one of which is moored up1 and the other down the stream4 ,austrian ,method of ,mooring4--,this method of mooring1 adopted by the ,austrians during the war of #ahff1 is shown at ,fig4 #dg4 ,it consists of a wooden triangular platform on which several heavy weights a1 a1 a are placed2 the mine is attached to this platform by means of three wire ropes b1 b1 b1 connected to the angles of the latter1 and fastened to three chains1 which by means of a catch holds the mine at the position required4 ,this catch consists of a pulley attached to the extremity of the wire rope of the platform1 through which the mooring chain of the mine is passed1 and fastened by a key at the required depth by means of a self-acting arrangement4 ,this key1 which is of considerable weight1 slips down as the mine is being hauled into position1 but the moment the chain is slacked1 two arms catch into a link of the chain1 and so hold the mine in position4 ,the weight of such a key is about #fj lbs4 ,it is fitted with nuts1 c41 to enable it to be taken to pieces4 ,this plan of mooring proved very effective in the harbours of the ,adriatic1 where there is hardly any tide or current to twist the mooring ropes1 or otherwise disturb the mines4 ,the ,austrians have lately adopted the mushroom sinker in place of the wooden platform and weights1 for their anchor4 ,single ,rope ,mooring4--,this simple method of mooring has after numerous exhaustive experiments been adopted as the most practicable and effective of all others4 ,whenever possible1 a wire instead of hempen cable should be used to connect the mine and its circuit closer to the mooring anchor1 as the former is less liable to twist1 kink1 or wear from friction than the latter4 ,a ground mine with circuit closer attached is represented at ,fig4 #dh1 where a is the wire mooring rope1 b the electric cable leading from the mine to the circuit closer1 ,c1 and c the cable leading from the firing station to the mine2 d is the oblong sinker attached to the mine1 and e the tripping chain leading to the shore1 to which the cable c is attached at intervals1 so that by underrunning the electric cable1 the tripping chain may be easily picked up1 and the mine raised4 ,illustration3 ,,moorings ,,for ,,submarine ,,mines4 ,,plate ,,xi ,at ,fig4 #di is shown a buoyant mine4 ,the only difference in the mooring of this and the one before described1 is that instead of resting on its anchor on the ground1 it is moored at a certain distance above its anchor d1 to which it is secured by a chain e4 ,fig4 #ej represents an electro contact mine4 ,m is the mine with circuit closer enclosed1 a the wire mooring rope1 d the mushroom anchor1 and b the electric cable leading from the mine to the disconnector ,d4 ,the mushroom sinker or anchor1 which is undoubtedly the most effective of all other forms of mooring anchors used for the purposes of anchoring submarine mines1 is shown at e1 ,fig4 #di2 the legs are added for use on rocky or hard bottoms1 under which circumstances the weight of the anchor should also be increased4 ,for ground mines the form of sinker shown at d1 ,fig4 #dh is employed2 it is of an oblong shape1 and hollowed out in the centre to allow of its being lashed close up to the mine4 ,large blocks of stones with their bases slightly hollowed are useful as extempore moorings1 so also is the one shown at ,fig4 #ea1 which consists of a strong heavy wooden shaft a1 with a number of wooden arms b1 b attached to its base2 this form of extempore sinker was considered very efficient by the ,american authorities4 ,the wooden weighted platform1 which was described at page #ef1 is also a very useful form of extempore sinker4 ,for dead weight moorings1 pigs of ballast1 heavy stones1 c41 may be used4 ,the weight of the anchor or sinker for mooring submarine mines is a very important consideration4 ,it will depend on the amount of buoyancy of the mine1 on the strength of current1 and on the nature of the bottom1 also whether the mines are to be hauled down to1 or moored with the anchor4 ,stotherd uses the following formula3 ,w #brt7,b#b ,p#b7 where ,b is the excess of the flotation over the weight of the charge of a given submarine mine2 ,p is the pressure exerted by any given current on the same buoyant mine2 ,w the weight of sinker necessary to overcome the tendency of the mine to move4 ,in still water ,p becomes nothing1 and therefore ,w equal to #b ,b1 that is1 in still water double the buoyancy of a mine is a sufficient weight for its anchor4 ,the value of ,p may be found from the formula ,p #djhe ,v#b1 where ,v is the velocity of the current in miles per hour4 ,from this equation ,p will be found in terms of pressure in pounds per square foot of flat surface1 which is nearly double that on the curved surface of a cylinder4 ,in regard to the amount of buoyancy of a submarine mine1 it has been found by actual practice that in the case of a mine moored in still water it should certainly be not less than the weight of the charge1 whilst if subjected to the lateral pressure due to a current1 it should be not less than three times the pressure exerted by the current4 ,it is always necessary to allow an excess of buoyancy over the calculated amount to counteract any leakage1 or other disturbing cause which might otherwise materially affect the efficiency of the mine4 ,there are two modes of placing a mine in position2 either by attaching the anchor1 with the cable necessary for the depth of water1 to the mine1 and lowering both together1 or by placing the anchor first1 and then hauling the mine down to it1 and by means of a catch1 fastening it at the required depth4 ,the first mode is exceedingly simple1 but except under very favourable circumstances cannot be relied on when firing by observation is the means adopted to explode a system of submarine mines4 ,the second plan is practically easy to carry out1 and by it a mine may be placed more accurately4 ,to enable either of the above methods to be properly carried out1 specially fitted steamboats1 c41 are requisite4 ,at ,fig4 #eb is represented a #db feet launch fitted for laying down a submarine mine by the first of the two modes enumerated above4 ,illustration3 ,,steam ,,launch ,,for ,,mooring ,,submarine ,,mines4 ,,plate ,,xii4 a is the mine2 b is the electric cable carried from the drum c to the charge1 and connected for use2 d is the circuit closer1 which is attached to the mine by its electric cable and mooring rope2 f is the mushroom sinker attached by means of its mooring chain to the mine1 it is suspended by a slip rope g1 which passes over a small crutch fitted with a sheave h2 i is a hollow iron derrick1 and k the tackle and fall for lifting mine into boat2 this derrick is formed of an iron tube about #c inches diameter1 #c_/h inch thick1 and #aj feet #f inches long2 it is attached to an iron tube mast of similar diameter and thickness to the derrick1 but #ab feet #c inches long1 an iron chain #f feet #f inches long and #e_/h inch diameter1 connects the derrick to the mast2 m is a leading sheave to keep the cable clear whilst it is being paid out2 l is a crab1 for working the tackle k1 c41 and c is the drum on which the electric cable is wound4 ,in connection with the defence of a harbour by a system of electrical submarine mines of large size1 it will be necessary to employ a service of steamtugs1 steamboats1 mooring-barges1 c41 specially fitted for such work4 ,one of the great advantages of the hauling down method of placing mines in position1 is1 that the anchors1 with the cables connected thereto1 may be carefully and accurately got into position during the time of peace1 and the mines themselves1 which should be kept in store ready fitted for immediate use1 need not be placed in position until they are actually required4 ,the drums used for reeling a multiple cable on1 are capable of holding half a nautical mile in length4 ,that used for a single core armoured cable is similar to but smaller than the aforesaid drum1 and is capable of stowing one nautical mile of such a cable4 ,for transportation wooden drums are ordinarily used4 ,,chapter ,,iv4 ,,defensive ,,torpedo ,,warfare--continued4 ,,closing the ,electric ,circuit4--,in connection with the system of coast defence by means of electrical submarine mines1 there are two distinct methods of effecting the closing of the electric circuit1 and consequently1 the firing battery being connected1 the explosion of the mine or mines1 which methods may be used separately1 or in combination1 and are as follows3-- #a4--,the self-acting method4 #b4--,the firing by judgment1 or observation method4 ,during the early days of submarine defensive warfare1 the latter method alone was used1 owing to the absence of anything like a practicable form of self-acting apparatus2 but within the last few years1 the former has almost entirely superseded the latter method1 except in very exceptional cases2 this revolution being due to the vast improvements that have been1 and still are being effected in the system of firing electrical submarine mines automatically4 ,use of ,circuit ,closers4--,electrical submarine mines may by means of an apparatus1 termed a circuit closer1 be rendered self-acting2 that is to say1 by the action of a vessel coming in contact with such an apparatus1 which may be either within the mine itself1 or within a buoy attached to the mine1 the electric circuit is closed1 and the mine in connection with the circuit closer so struck1 exploded4 ,the essential feature of such a mode of closing the electric circuit is1 that electrical submarine mines may be rendered either active or harmless1 at the will of the operator1 which is effected by the putting in1 or taking out of a plug1 by which means the firing current is either thrown in1 or out of the circuit4 ,circuit closers4--,many different forms of circuit closers have been devised1 among which the following seem the most suitable and are those generally used3-- #a4--,mathieson's inertia circuit closer4 #b4--,mathieson's spiral spring circuit closer4 #c4--;,austrian self-acting circuit closer4 #d4--,mc,evoy's mercury circuit closer4 #e4--,mc,evoy's weight magneto circuit closer4 ,mathieson's ,circuit ,closer4--,this form of circuit closer has been adopted by the ,english government in connection with their system of defence by electrical submarine mines4 ,the details of this apparatus are shown at ,pl4 xiii4 ,fig4 #ec1 a is a gun-metal dome screwed on to a metal base b1 its foot resting on a gutta percha washer c1 so as to exclude any water2 d is a cap screwed on to the top of the dome1 and made watertight by the leather washer e2 f is a guard cap screwed into the cap d1 this is to keep the spindle of the circuit closer steady during transport1 and would be removed when the apparatus is prepared for service2 g is the ebonite base plug through which pass the insulated wires ,e and ,l2 h is an hexagonal collar1 working in the metal base plate b1 by means of which1 and the brass collar i1 and the leather washer k1 the base plug is secured1 and water is excluded from the interior of the circuit closer2 l1 l1 l are brass columns supporting a circular ebonite piece m2 n is a metal bridge screwed on to the base plate b1 into which is screwed the spindle p1 both of which are prevented from moving after being screwed up by the set screws r and s4 ,the spindle p carries a leaden ball t1 which is supported upon the rest v1 and is secured in position by the screw nut w2 x is an india rubber ring1 the object of which is to prevent any damage being done to the spindle should the ball when set in action by a heavy blow from a passing vessel be brought into contact with the dome2 #b is a brass disc attached to the spindle carrying an ebonite disc #d1 connected to it by screws2 #f is a brass contact ring also fixed to the ebonite disc #d1 provided with a screw #h1 for the attachment of one of the base plug wires1 and with platinised projections #c1 #c1 #c1 ,fig4 #ef4 ,the contact ring #f is completely insulated from the spindle and brass disc #b4 ,three contact springs #e1 are attached to the circular ebonite piece m1 and the faces opposite to the platinised projections of the disc #b are also platinised4 #g shows the contact screws of the connecting pieces1 which serve also as adjusting screws to regulate the sensitiveness of the apparatus1 the points of which as well as their bearings on the springs are platinised4 ,the springs are connected together by means of the wires #i1 ,fig4 #ee1 one end of which is secured to the connecting piece by the screw #aj1 and the other passes through to the top of the ebonite piece1 and is attached to the top of the spring next in succession to that to which it is fixed below4 ,one terminal of a coil of #ajjj ohms resistance 7which is used for testing purposes7 is attached to the line ,l1 terminal of the ebonite base plug1 which latter is also connected to the screw #h1 on the circumference of the contact ring #f2 the other terminal of the resistance coil is connected to the earth1 ,e terminal of the base plug4 ,a bare copper wire of ,no4 #af ,b4 ,w4 ,g4 connects the top of the last contact spring with the set screw s2 a piece of similar wire jointed to it is passed round one of the brass collars and connected to the screw r4 ,as a precaution against bad contact1 the contact springs are connected together by bare wires ,a1 ,b1 ,c4 ,this completes the connections for the signalling circuit1 the earth being formed by the body of the instrument2 ,d is a hole left in the metal base for the passage of the insulating wire which connects the earth plate to the earth ,e terminal of the base plug4 ,testing ,current4--,for testing purposes the current from the test battery arrives by the line wire ,l1 and passes thence through the resistance coil to earth by means of the wire ,e1 which is attached to a zinc earth plate placed in a recess in the jacket of the circuit closer4 ,action of the ,circuit4--,the action of the apparatus is as follows3-- ,closer4--,on the circuit closer being struck1 the weight of the lead ball t causes the steel rod p to be deflected and brings the brass ring #f in contact with one of the springs #e2 the signalling current which up to this moment has been passing through the #ajjj ohms coil to earth1 then passes to the contact ring #f 7avoiding the resistance coil7 thence to the spring which is in contact with it1 and from there by means of the wire connections to the set screws s and r1 and so to earth through the metal body of the apparatus2 the effect of the resistance coil being thus eliminated1 is to strengthen the signalling current1 and thus enable it to work the shutter apparatus1 by which means the firing current is thrown into circuit and the mine exploded4 ,illustration3 ,,mathieson',s ,,circuit ,,closer4 ,,plate ,,xiii ,circuit ,breaker4--,by altering the mode of connecting the wires1 the above apparatus may be used as a circuit breaker1 that is to say1 the signal may be given1 and the mine exploded by the cessation of a passing current1 instead of by the closing of the electric circuit4 ,this system was specially designed for use with platinum wire fuzes1 but is rarely used4 ,circuit ,closer of ,electro ,contact ,mines4--,when the inertia circuit closer is employed in connection with electro contact mines1 the circular ebonite piece m is replaced by a similar shaped piece of brass1 and which is in metallic connection through the brass pillars l1 l1 l with the mass of the metal of the apparatus which forms the earth plate4 ,the insulated wire of the base plug is connected to one pole of a platinum wire fuze1 the other pole of which is connected by another wire to the outer metal rim of the disc of the spindle4 ,as long as the circuit closer remains undisturbed1 a break will remain in the circuit1 which is due to the ebonite insulation between the spindle and the outer metal rim of the disc2 but the moment the apparatus is struck1 which causes the spindle to vibrate1 the outer metal rim will come in contact with one of the springs completing the circuit1 through the circular metal portion and the pillars of the circuit closer to earth4 ,adjustment of ,circuit ,closer4--,the sensitiveness of ,mathieson's inertia circuit closer is determined by the distance between the disc #d and the springs #e1 #e1 #e1 which is regulated by means of the adjusting screws #g1 #g1 #g1 which press against the inner faces of the springs4 ,owing to the great weight of the leaden ball1 when by any cause the circuit closer is inclined for a length of time1 a permanent set is given to the spindle1 thereby destroying the adjustment of the instrument4 ,improvements in the ,inertia ,circuit ,closer4--,to remedy this very serious defect1 a cylinder of india rubber is substituted for the leaden ball2 a circuit closer so fitted is also less affected by the action of counter mines1 which is a very important advantage4 ,mathieson's ,spiral ,spring ,circuit ,closer4--,a sectional elevation of this form of circuit closer is shown at ,fig4 #eg4 ,it consists of a brass base a1 provided with a grooved flange for carrying a gutta percha washer1 and it has also an hexagonal projection for the purpose of screwing the circuit closer into the gun-metal mouth of its air-tight cylinder1 or buoy2 b is a brass dome enclosing the apparatus for the purpose of protecting it from injury1 and also by means of india rubber washers to prevent an ingress of water1 should the circuit closer case become injured1 and leak2 c is a brass collar to which the brass contact springs i1 i are attached1 and which are regulated by the set screws j1 j2 a brass spiral spring d carries a metal rod e1 which supports a brass ball f1 surrounded by an india rubber band h4 ,a contact disc g is secured to the base of the spindle e1 but insulated from it by an ebonite boss2 k is an ebonite base plug with two channels in it1 through which the wires m1 m#a pass4 ,an ,improvement on the ,inertia ,circuit ,closer4--,this instrument is a vast improvement on the inertia apparatus previously described1 being more simple and more certain in its action1 a desideratum in all circuit closers2 but notwithstanding1 up to the present time ,mathieson's inertia apparatus has been used by our government1 to the exclusion of all other instruments of a similar nature1 some of which were proved to be far superior when subjected to the crucial test of actual practice4 ,austrian ,self-acting ,circuit ,closer4--,this form of circuit closing apparatus1 which is purely a self-acting one1 that is to say1 a mine so fitted cannot be fired at will1 is shown at ,fig4 #eh4 ,it consists of several buffers a1 a1 a1 which by means of strong springs are held in position1 their heads projecting outside the torpedo case b2 on being pressed in by the contact of a passing vessel1 the ends of these buffers would be forced against a ratchet wheel c1 which is also kept in position by means of a spring4 ,several strong pieces of wood d1 d within the case keep the buffers and their attached arms in the proper direction1 and also afford rigidity to the torpedo case4 ,the brass ratchet wheel c being put in motion carries round with it a central arrangement e1 the lower part of which is shown at ,fig4 #eh1 ,a4 ,this portion consists of a cylinder of brass f divided into two parts insulated one from the other by a piece of ebonite g2 on one side of this cylinder there are three arms of brass1 h1 i1 and k1 and on the other there are two arms1 l and m1 all of which are insulated from each other4 ,illustration3 ,,austrian ,,circuit ,,closer1 ,,mercury ,,circuit ,,closer4 ,,plate ,,xiv ,the arm h is close to1 but insulated from a metal plate n1 which latter is permanently connected with the conducting wire leading from the firing battery1 and thus while in a state of rest is electrically charged2 beyond the arm i is a spring o1 which is connected with the earth1 and in such a position that when the central portion is moved round1 this spring o comes in contact with the arm i1 and the plate n with the arm h simultaneously1 and the circuit is thus completed through earth to the battery1 but the current of electricity does not pass through the fuze4 ,the arms k1 l on the opposite sides of the cylinder1 and consequently insulated one from the other1 are connected with the fuze1 and the arm m is connected with the earth4 ,on a further pressure of the vessel on the buffer1 the arm i is pushed beyond the spring1 and in contact therewith1 and consequently the circuit by earth to the battery is broken1 while the contact of the arm h and plate n is still retained1 and the current is passed by the arm k through the fuze to the arm l1 and then to earth through the arm m1 thus completing the electric circuit of the firing battery through the fuze1 and to exploding the mine4 ,the spring acts as a circuit breaker1 and by means of an intensity coil in connection with the firing battery1 the current is only passed through the fuze when at the point of greatest intensity4 ,by detaching the firing battery1 the channel defended by such submarine mines may be rendered safe4 ,fuze only in ,circuit at ,moment of ,firing it4--,one of the principal objects to be gained by the employment of such an arrangement for the closing of the electric circuit in connection with submarine mines1 is the prevention of premature explosion from induction which might be caused by the proximity of any atmospheric electricity1 the fuze in this system being entirely cut out of circuit until the moment when it is necessary to fire it4 ,the ,austrians employed this form of circuit closing instrument during the war of #ahff1 and still continue to use it in connection with their coast defence by submarine mines4 ,mc,evoy's ,mercury ,circuit ,closer4--,at ,fig4 #ei is represented a longitudinal section of a circuit closer of this construction4 ,it is placed in the mine in such a manner that when undisturbed it maintains an approximately upright position4 ,it consists of a metal tube a into which the cup b of vulcanite1 or other insulating material is fixed4 ,the cup is contracted at some distance from the top by the perforated plug c1 which is also of insulating material2 d is a metal pin fixed into the bottom of the cup b1 it is connected with the wire e1 which is insulated and passes to the battery2 f is a metal plug closing the tube a and the cup b at the top2 g is a wire attached to the plug f1 and passing from it to an earth connection4 ,the cup b is filled with mercury up to the level of the plug c4 ,by the contact of a passing vessel the instrument would be tilted sufficiently to cause the mercury to flow into contact with the metal plug f1 thus completing the electric circuit and exploding the mine4 ,this form of circuit closer1 though not generally adopted1 would1 on account of its being less liable to derangement by the motion of the waves1 or by the explosion of an adjacent or counter mine1 seem to fulfil the many requirements of a circuit closer for general service4 ,mc,evoy's ,weight ,magneto ,circuit ,closer4--,this form of circuit closer1 which is shown in section and plan at ,figs4 #fj and #fa1 is one of the most important improvements that has ever been effected in such apparatus1 and bids fair to become universally adopted4 ,a heavy metal conical shaped weight a 7,fig4 #fj71 hollowed out in its base and working in a ball and socket joint b1 rests on a solid brass base c1 and is so arranged that on the apparatus being struck1 the weight a will fall over1 pivoting on one of its supports d1 d2 e is a band of india rubber1 encircling the weight a1 for the purpose of preventing a jar on its falling against the sides of the brass cylinder f1 which contains the weight a and joint b4 ,a brass rod g1 connected to the ball and socket joint1 passes through the base c1 through a strong spiral spring h 7which latter rests on an adjusting screw k71 through a piece of ebonite l1 which supports the bobbins and core m1 m#a2 then between these bobbins m1 m#a through an armature n1 which is pivoted at p2 and lastly through a slight spiral spring o1 which is kept in position by the adjusting screw i4 ,the armature n is fitted with a small piece of brass r1 so arranged that when it 7the armature7 is in the position shown in ,fig4 #fj1 this piece of brass r does not make contact with the two strips of metal1 s1 s1 between which it1 r1 works2 but when the armature n is in contact with the cores of the bobbins m1 m#a1 then the piece of brass r makes contact with the metal strips s s1 and so makes a short circuit for the electric current4 ,an ordinary telephone t1 ,fig4 #fa1 in which some small shot1 bells1 c41 are placed1 is fixed to the top of the brass cylinder f4 ,action of ,circuit ,closer4--,the action of this apparatus is as follows3-- ,on the mine carrying this form of circuit closer being struck by a passing vessel1 the weight a is caused to fall over towards the side of the brass cylinder f1 thus allowing the strong spiral spring h to act on the brass rod g in an upward direction1 by which means the armature n is brought into contact with the soft iron cores of the bobbins m1 m#a4 ,illustration3 ,mc4,,evoy',s ,,magneto ,,electro ,,circuit ,,closer4 ,,plate ,,xv ,the connections of the wires are made as follows3-- ,the line wire w is led through the base of the apparatus and connected to a piece of brass under the ebonite support l1 in connection with one of the wires of the bobbin m1 the other wire of which is attached to the metal strip s2 the wires of the bobbin m#a are connected1 the one to the metal strip s#a1 the other to a piece of brass under the ebonite support l2 from this latter piece of brass a wire w#a is led to the brass screw x4 ,the wires w#b1 w#c1 from the fuzes are led1 the one to the brass screw x1 the other to a screw y1 which forms through the metal of the apparatus the earth plate4 ,one of the wires of the telephone t is connected to the brass screw x1 the other w#d is connected to the piece of brass to which the line wire w is also attached4 ,while the circuit closer remains in a state of rest1 the current from the signalling battery flows along the line wire w1 up the telephone wire w#d1 through the telephone which has a high resistance1 then by the wire w#b through the fuzes1 and to earth by the wire w#c4 ,on the circuit closer being struck1 by which cause the armature n is brought up to the cores of the bobbins m1 m#a1 and the piece of brass r in contact with the metal strips s1 s#a1 the signalling current1 instead of circulating through the high resistance of the telephone t1 passes round the bobbin m1 down the metal strip s1 across the brass piece r1 up the metal strip s#a1 round the bobbin m#a 7thus forming an electro magnet of m1 m#a71 and by the wire w1 direct through the fuzes to earth1 and so explodes the torpedo4 ,the effect of the telephone resistance being cut out1 is to strengthen the signalling current1 and enable it to work the shutter apparatus and so throw the firing battery in circuit and explode the mine4 ,the advantages of this circuit closing apparatus are3-- #a4--,simplicity4 #b4--;,compactness4 #c4--;,increased certainty of action1 due to the sustained contact of the armature n1 on the apparatus being struck4 #d4--;,additional means of testing a system of electrical submarine mines1 which is afforded by the telephone3-- ,when this form of circuit closer is put in action by a friendly vessel coming in contact with it1 or when experiments are being made1 the signalling current must be reversed1 so that no doubt may exist as to the armature n having dropped1 on the apparatus coming to rest4 ,the telephone test indicates whether the circuit closer is in position or not1 the shot1 c41 within the telephone being shaken about by the movement of the buoyant circuit closer1 the noise so created is readily distinguished by the receiving telephone at the station4 ,another form of submarine mine is that known as the ,electro ,mechanical mine4 ,the difference between this form and an ordinary mechanical mine is1 that the exploding agent is electricity1 and that it may be converted into an electro contact mine if desirable4 ,description of a ,russian ,electro4--,the electro mechanical mine1 used by the ,russians during the late ,turco-,russian war1 is shown in elevation and section at ,figs4 #fb and #fc4 ,mechanical ,submarine ,mine1 used by them during the late ,turco-,russian ,war4--,a is the conical shaped case2 ,b the loading hole2 ,c the base plug2 ,d1 ,d1 c41 are five horns1 screwed into the head of the case ,a2 these are composed of a glass tube ,a1 containing a chlorate of potash mixture1 enclosed in a lead tube ,b1 over which is screwed a brass safety cylinder ,c2 when ready for action this latter tube ,c is removed2 directly beneath each of the horns ,a1 on the inside of the case1 as at ,e1 is a thin brass cylinder1 closed at one end by a piece of wood d1 and containing several pieces of zinc and carbon1 arranged in the form of a battery1 the zinc and carbon wires z and x being led through the piece of wood d2 ,f is a copper cylinder containing the priming charge of gun-cotton g1 and detonating fuse f2 the terminals of the fuze are connected to two insulated wires1 w and w#a1 the former of which is led direct to the loading hole ,b1 and attached on the inside to the five zinc connecting wires z1 c42 the latter is attached to one end of a safety arrangement ,s1 the other end of which is connected to the wire w#b1 which is attached on the inside to the carbon wires x1 c42 the safety arrangement ,s consists of an ebonite cylinder1 containing a brass spiral spring fixed to one end of it1 and pressing against a brass plate at the other1 thus preserving a metallic connection between the wires w#a1 and w#b2 the mine is rendered inactive by pressing the spring down1 and inserting a piece of ebonite between it and the plate4 ,its ,action4--,the action of this form of electro mechanical submarine mine is very simple2 the brass safety cylinders c1 c1 c41 being removed on a vessel striking either of the horns1 ,d1 ,d1 c41 the lead tube b is bent1 causing the glass tube a to be broken1 and the mixture contained therein to flow into the cylinder ,e1 instantly generating a current of electricity in the zinc carbon battery1 and exploding the mine4 ,mode of ,converting into an ,electro ,contact or ,observation ,mine4--,to convert this mine into an electro contact one1 it is only necessary to connect the wires w#a and w#b to other wires leading from the shore2 also by replacing the horns ,d1 ,d by solid brass screw plugs1 the mine may be converted into an ordinary observation one4 ,in this case the two wires w and w#a attached to the fuze f1 terminals would have to be connected to the observation instruments on shore4 ,turkish ,vessel sunk4--,it was by means of one of these electro mechanical mines1 that the ,turkish gunboat ,suna was sunk at ,soulina4 ,firing by observation1 that is to say1 effecting the ignition of an electrical submarine mine at the precise moment of a hostile vessel being vertically over it1 through the agency of one or two observers stationed at a very considerable distance from the mine1 should1 with the very perfect self-acting circuit closers that exist at the present time1 be resorted to only in very exceptional cases1 or in connection with the self-acting system4 ,there are two defects1 which are common to all methods of firing submarine mines by observation1 and these are3-- #a4--;,at night time1 or in foggy weather1 it cannot be employed4 #b4--;,it is necessary to employ at least two observers1 at a considerable distance apart1 who to effect a proper action at the right moment1 must work in perfect unison4 ,these defects alone are sufficient to explain the preference given to a self-acting method of closing the electric circuit at the precise moment of a vessel being in position over a mine by those governments who have adopted electrical submarine mines as a means of coast defence4 ,methods of ,firing by ,observation4--,there are several methods of firing by observation1 of which the following are the ones principally used3-- #a4--;,by pickets or range stakes4 #b4--;,by cross bearings4 #c4--;,by intersectional arcs fitted with telescopes4 #d4--,the ,prussian system4 ,intersection by ,pickets or ,range ,stakes4--,in narrow channels and at short distances1 this system of ascertaining the relative position of a hostile vessel and a submarine mine may be used1 provided that skilled and careful men are employed to work it4 ,two or more pickets or stakes are arranged in front of the firing station in such a manner that a vessel passing up the channel on the prolongation of these stakes will be over a mine4 ,this arrangement should of course always be considered as an extempore one2 it was used on several occasions by the ,confederates during the ,american civil war4 ,firing by ,cross ,bearings4--,the simplest method of so determining the relative position of a vessel and a submarine mine1 and exploding it at the right moment1 is that in which observers are placed on the prolongation of the mines4 ,this mode is shown at ,fig4 #fd1 where m#a1 m#b1 m#c1 c41 and n#a1 n#b1 n#c1 c41 are the mines2 ,a and ,b1 the points in prolongation of the mines where the observers are stationed2 ,d the firing battery1 and s1 and s#a two hostile vessels4 ,at the stations ,a and ,b firing keys are placed1 at the former one for each separate mine1 perfectly distinct and insulated from each other1 at the latter a single key4 ,the pivot points of the series of keys at ,a are connected by separate wires to one pole of the firing battery ,d1 the other pole of which is connected by a single cored insulated cable to the pivot point of the key at ,b2 the contact points of the series of keys at ,a are connected by separate line wires as ,a m#a1 ,a m#b1 ,a m#c1 c41 to the different mines1 while the contact point of the key at ,b is put to earth4 ,thus it will be seen that1 in the case of the row of mines1 m#a1 m#b1 c41 unless the key at ,b1 and the key at ,a1 of either of those mines are both pressed down at the same instant1 no current can pass1 and therefore none of those mines can be exploded4 ,illustration3 ,,russian ,,submarine ,,mine1 ,,firing ,,by ,,observation4 ,,plate ,,xvi ,in the case of the vessel ,s1 though at ,c1 she is on the prolongation of the line ,a m#e1 ,c1 and therefore the key of the mine m#e1 is pressed down at ,a1 yet not being on the prolongation of the line ,b1 ,e1 the key at ,b is not pressed down1 therefore the firing battery is not thrown in circuit1 or the mine m#e exploded1 but when the vessel s reaches the position ,n1 that is over the mine m#c1 she being on the prolongation of the lines ,a m#c1 and ,b ,e1 the key 7m#c7 at ,a1 and the key at ,b would both be pressed down1 and therefore the mine m#c exploded1 and the ship destroyed4 ,in the case of a vessel passing through an interval between any two mines at such a distance as to be out of the radius of destructive effect of either of the mines belonging to the first row 7which is shown at s#a17 only the key at ,b would be pressed down1 and thus the vessel enabled to pass safely through1 but only to come to grief at the second or third row of mines1 provided they have been properly placed1 and separate though similar arrangements as in the case of the line of mines1 m#a1 m#b1 c4 have been made4 ,firing by a ,preconcerted ,signal4--,at ,fig4 #fe is represented a somewhat similar1 though a much simpler plan of the foregoing system1 by employing a preconcerted signal at the station ,b in the place of the firing key and insulated cable1 as in the former case4 ,the only material difference in the arrangement of these two methods1 is that in the latter case the pole of the firing battery at ,a1 which in the former case was connected to the firing key at ,b1 is put direct to earth4 ,as will be readily understood1 this latter system requires great coolness and nerve on the part of the operator at ,a1 who has not only to watch the vessel passing across his intersections1 but also to be on the alert to receive the signal from the observer at ,b4 ,should it ever be necessary to adopt this latter system1 it will be found advisable to employ two men at station ,a1 one to watch station ,b1 the other to attend to the firing key and intersections4 ,a separate signal-flag for each line of mines1 and also a separate firing arrangement1 would be required4 ,as in many cases it would not be practicable to have a station in such an advanced position as at ,b1 in ,figs4 #fd and #fe1 on account of the danger of its being cut off by an enemy1 another combination becomes necessary4 ,in this instance the station ,b is placed on the opposite side of the river1 c41 to that on which the station ,a is placed1 and a series of firing keys1 instead of a single one1 is here used1 necessitating a multiple cable between the stations ,a and ,b1 in the place of single cored cable2 the manner of manipulating this method is very similar to that previously described4 ,firing by ,intersectional ,arcs fitted with ,telescopes4--,the foregoing methods of firing by cross bearings are replete with many serious defects1 to remedy which1 to a considerable extent1 special arrangements have been devised1 that is1 the employment of intersectional arcs fitted with telescopes at the stations ,a and ,b4 ,figs4 #ff and #fg show the arrangements of these arcs1 the former being the one used at the firing station ,a1 the latter at the converging station ,b4 ,at each station one arc is provided for each row of mines placed in position4 ,the firing arc ,fig4 #ff consists of a cast iron frame a1 with three feet b1 b1 b1 these being provided with levelling screws4 ,to ascertain when this frame is level1 a circular spirit level is attached thereto1 a telescope d provided with one horizontal and three vertical cross wires1 supported on ,y's1 admitting of vertical motion and attached to an upright e4 ,a mill-headed screw f enables the telescope d to be raised or lowered2 the telescope1 which is rigidly connected to a vernier g1 traversing over a graduated arc h1 can be moved rapidly in a lateral direction by means of a rack and pinion arrangement i1 and it can be clamped in any position by means of the screw h4 ,sights are fixed on the telescope in a vertical plane passing through its axis4 ,to the outer rim of the frame of the arc1 which is smooth1 are secured the sights l l 7shown on a large scale at ,fig4 #fh71 to give the direction of the mines4 ,these sights are provided each with a brass point of ,v form1 m1 and a binding screw1 n1 in metallic connection with each other1 but insulated by means of an ebonite plate from the rest of the metal of the sight4 ,one end of a short piece of insulated wire is attached to the binding screw n1 and the other passes through a hole in the base of the sight and projects below it2 o is a brass tube rigidly connected to and moving with the upright carrying the telescope d1 and projecting in front of this latter4 ,a brass spring p 7see ,fig4 #fi7 is attached to1 but insulated from the outer extremity of this tube1 and is so arranged as to make contact with the ,v point m on the sight1 by means of a corresponding projection fitted to its under side4 ,an insulated wire passing the tube o1 the outer end of which is connected to a screw on the spring p1 forms a metallic connection between this projection and the firing key4 ,at ,fig4 #fh is shown an enlarged view of the front of the sight2 in addition to the ,v projection m1 and binding screw n1 it is fitted with a capstan-headed screw to bear against the inner rim of the frame1 and a thin wire upright t for giving the alignment of the mine1 to which a disc is attached1 on which the number of the mine is affixed4 ,when the distance between the station and the mine is only about one mile1 an ordinary eyepiece is used in the place of the telescope d4 ,at ,fig4 #fg is represented the arc employed at the converging station1 which with the exception of there being no tube o1 and only one sight1 is precisely similar in construction to the one used at the firing station1 and which has been described4 ,illustration3 ,,apparatus ,,for ,,firing ,,by ,,observation4 ,,plate ,,xvii ,application of the ,intersectional ,arc ,method4--,the application of the method of firing by observation1 by means of intersectional arcs fitted with telescopes1 is shown at ,fig4 #gj4 ,c1 ,d1 and ,e are three of the larger kind of arcs1 one being used for each row of mines at the firing station ,a4 ,at the converging station ,b1 one of the smaller arcs is used for each row of mines1 as shown at ,f1 ,g1 and ,h4 ,s1 ,s#a1 ,s#b1 are the signalling apparatus1 the ,f terminals of which are connected to the sights l1 l1 l1 ,fig4 #fi1 of arcs ,c1 ,d1 ,e4 ,firing keys a1 a1 a at station ,a are connected to each arc1 and to three of the cores of the cable connecting the two stations ,a and ,b1 respectively4 ,at the converging station ,b1 three firing keys b1 b1 b are connected to earth and to three cores of the connecting cable respectively4 ,the remaining core of this cable is connected to the recording instruments d1 e4 ,the action of the arcs1 c41 will be readily understood from the diagram at ,fig4 #gj4 ,this arrangement does not interfere with the action of the circuit closer1 as all that is effected by the observing arc circuit is to put the signalling battery current at the converging station ,b to earth instead of at the circuit closer4 ,prussian ,system of ,firing by ,observation4--,the principle on which this system is based1 depends upon the proposition that if c d1 in the triangle shown in ,fig4 #ga1 be always kept parallel to ,h ,b1 then ,a c1 c d1 d ,a bear exactly the same proportion to each other as ,a ,b1 ,b ,h1 ,h ,a do to one another2 so that by means of the small triangle ,a d c1 the lengths of the sides of the large triangle ,a ,b ,h can be obtained1 and hence the position of the point ,h1 the base ,a ,b being of course known4 ,in ,fig4 #ga at ,a there is a slate table representing the roadstead1 and upon it the exact position of every torpedo is laid down1 corresponding to their position in the roadstead4 ,at ,a and ,b1 #ejj yards apart1 telescopes having cross wires are placed2 at ,a a long narrow straight-edged strip of glass ,a d is arranged to move in unison with the telescope at ,a2 and by the application of dynamo electricity1 a similarly constructed piece of glass c d moves in exact unison with the telescope at ,b1 and having its pivot at ,c2 that is to say1 ,c d keeps parallel with ,b ,h1 the line of sight of the observer at ,b4 ,then if the observers at ,a and ,b have got a ship in their telescopes1 the point of intersection d of the two pieces of glass ,a d and ,c d gives the position of the ship on the slate table at ,a1 and when this point d comes over the position of any one mine on the slate1 it is known that the ship is over that particular mine in the harbour1 and she may be destroyed accordingly1 by throwing the firing battery into circuit4 ,by the employment of electricity and a mirror1 the great defect of this method1 viz41 the necessity of employing four people to manipulate it1 would be remedied4 ,the foregoing is a modification of ,siemens's method of ascertaining distances at sea1 c4 ,rules observed in ,planting ,mines4--,in placing a system of submarine mines in position1 the following are some of the chief points to be attended to1 this work depending in a great measure on local circumstances1 and on the method that is to be adopted in exploding and mooring them3-- #a4--,the plan of defence must be carefully laid down on a chart1 on a scale of not less than six inches to the mile1 and on this plan are to be marked the sites of the observing stations1 the positions of each mine1 circuit closer1 and junction box1 with their corresponding numbers1 and also of the electric cables4 #b4--,the position of each mine having been determined1 should be marked off by buoys4 #c4--,the utmost care should be taken to lay the electric cables1 so that they shall be as far as possible away from the mines in the vicinity of which it may be necessary to take them1 so as to lessen the liability of injury to them1 by the explosion of the latter4 #d4--,the electric cables should be laid parallel1 and never be allowed to cross directly over each other1 otherwise the operation of underrunning them will be much complicated1 also a certain amount of slack should be allowed to facilitate in picking the cables up for repair1 c4 #e4--;,every manner of device is to be used to conceal the electric cables1 such as laying dummies1 making detours inland1 c4 #f4--;,all marks indicating position of the mines to be removed1 after the mines have been placed in position4 #g4--,the identity of each cable and mine to be very carefully preserved throughout1 by means of a number4 #h4--;,a number of electro contact mines should be placed in advance of the leading line of mines1 at irregular intervals1 to prevent the enemy1 having once ascertained the position of one mine of a line1 from knowing within limits the position of the others of that line4 ,illustration3 ,,systems ,,of ,,defence ,,by ,,submarine ,,mines4 ,,plate ,,xviii ,in connection with a system of defence by electrical submarine mines1 the following batteries are required3-- #a4--;,firing battery4 #b4--,signalling1 or shutter battery4 #c4--,testing battery4 #d4--,telegraph battery4 ,firing ,battery4--,the firing battery should be suited to the nature of the fuze employed1 and should possess considerable excess of power to enable it to overcome accidental defects1 such as increased resistance in the various connections1 or defective insulation in the line wire1 c4 ,as platinum wire or low tension fuzes are now universally adopted as the mode of ignition for submarine mines1 it will be only necessary to describe those electrical batteries which are most suitable as an exploding agent in connection with such fuzes2 these are as follows3-- #a4--,siemens's dynamo low tension machine4 #b4--,von ,ebner's ,voltaic battery4 #c4--;,chromic acid or ,bichromate ,voltaic battery4 #d4--,leclanch's ,voltaic battery4 ,siemens's ,low ,tension ,dynamo ,electrical ,machine4--,this instrument consists of an electro magnet and an ordinary ,siemens armature1 which1 by the turning of a handle1 is caused to revolve between the poles of the electro magnet4 ,the coils of the electro magnet are in circuit with the wire of the revolving armature1 and during rotation the residual magnetism of the soft iron electro magnet cores at first excites weak currents which pass into the electro magnet coils1 increasing the magnetism of the core1 thus inducing still stronger currents in the armature wire4 ,this accumulation by mutual action goes on until the limit of magnetic saturation of the iron cores of the electro magnets is reached4 ,by the automatic action of the machine1 the powerful current so produced is sent into the leading wire or cable to the fuze to be exploded4 ,in this apparatus the electric current passes continuously through the line wire until a sufficiently powerful current is generated to heat or fuze the bridge of the fuze1 and so ignite the gun-cotton priming4 ,the coils of the armature and electro magnets are wound with wire of large diameter1 to a total resistance of #h to #aj ,siemens units1 or #gf to #ie ohms1 in about #b1jjj windings4 ,with a platinum wire weighing #afe grains per yard1 #f-a_/b inches can be fuzed on short circuit1 and #ad inches can be heated to redness4 ,the total weight of this machine1 which is manufactured by ,messrs4 ,siemens ,brothers1 is about #fj lbs4 ,advantages of ,siemens's ,dynamo ,electrical ,machine4--,the advantages of such a machine over ,voltaic apparatus are3-- #a4--,the absence of chemical agents4 #b4--,there is less liability to get out of order4 #c4--,no special knowledge is required to work them1 or to keep them in order4 #d4--;,greater durability4 ,the great defect of this and all similar machines is that the electric force has to be developed by turning a handle for a certain time before it is possible to generate a current sufficiently powerful to ignite a fuze1 which defect1 in connection with a system of defence by self-acting submarine mines1 particularly at night1 renders them inferior to ,voltaic batteries1 as under such circumstances1 an apparatus is required that will cause an electric current to flow at any moment when the circuit is completed4 ,the application of steam power would to a certain extent remedy the above-mentioned defect1 but the cost of such a method1 compared to that of a ,voltaic arrangement1 would be far too great to allow of its superseding the latter arrangement4 ,von ,ebner's ,voltaic ,battery4--,this form of ,voltaic battery1 which may be considered as a modification of that known as ,smee's1 was designed by ,baron von ,ebner1 colonel of the ,austrian imperial corps of engineers1 for use in connection with the ,austrian system of submarine defence1 by self-acting electrical mines4 ,a section of one of these cells is shown at ,fig4 #gb4 ,it consists of a glass vessel a1 to contain the diluted sulphuric acid1 within which is suspended a plate b of platinised lead1 which is bent round into a cylindrical form to fit close around the inner surface of the glass vessel4 ,in the centre of this latter is hung a porcelain perforated cup c1 containing some cut-up zinc and mercury to keep it 7the zinc7 amalgamated4 ,the top of each cell is furnished with a porcelain cover1 through which the wires attached to the positive and negative poles of the cell project4 ,due to the large quantity of liquid contained in the cell1 the tendency to alter its internal resistance is retarded2 also by the arrangement of the porcelain cup1 above detailed1 the consumption of zinc and mercury1 which in an ordinary ,voltaic battery is very considerable1 is materially diminished4 ,chromic ,acid or ,bichromate ,battery4--,this form of battery is very similar to ,grove's1 the difference being that1 in the place of the nitric acid as the exciting liquid1 either chromic acid1 or a solution of bichromate of potash1 sulphuric acid and water is substituted4 ,a form of this battery1 as designed by ,dr4 ,hertz1 is used in connection with the ,german system of torpedo defence4 ,leclanch ,voltaic ,battery4--,this form of ,voltaic battery was invented by ,m4 ,leclanch1 some twelve years ago4 ,at ,fig4 #gc is shown a cell of this battery in its original form4 ,the positive pole a consists of a plate of graphite in a porous pot b1 and surrounded by a mixture of peroxide of manganese and graphite4 ,the negative pole c is a rod or pencil of amalgamated zinc4 ,the whole is enclosed in an outer vessel of glass d containing a solution of sal ammoniac4 ,a modified form of the ,leclanch cell as used in a firing battery is shown at ,fig4 #gd4 ,it consists of an ebonite trough or outer vessel a about #af long1 #i deep1 and #b-c_/d wide4 ,the negative pole or zinc plate b is of similar shape to the trough a1 but with its base removed1 and does not fit the trough exactly1 the space between it and the trough being left to ensure the former being completely surrounded by the sal ammoniac solution2 the positive pole1 or carbon element1 consists of four gas carbon plates c attached together at their head by means of lead1 and enclosed in a flannel bag1 in which they are firmly embedded in the peroxide of manganese mixture2 the positive element is of such a shape that it fits loosely between the sides1 and is nearly of the same height as the zinc plate4 ,the object of such a form of cell was to obtain an electric current of large quantity1 with as few cells as possible1 by which means the loss of power which might occur from the employment of a great number of small cells is avoided4 ,advantages of a ,leclanch ,firing ,battery4--,the advantages of the ,leclanch firing battery are3-- #a4--,the absence of chemical action when the battery circuit is not complete1 and consequently there is no waste of material4 #b4--,requires little or no looking after4 #c4--;,it may be kept ready for action in store without in any way deteriorating4 #d4--;,it is comparatively very cheap4 ,these advantages combine to make a ,leclanch battery the most suitable of any other form of electrical battery for use as the exploding agent for electrical submarine mines1 and it is now universally used for such purposes4 ,signalling ,battery4--,the signalling battery should be so constituted as to be capable of working the electro magnet of the shutter apparatus effectually when the circuit is closed direct to earth1 and yet not so powerful as by the continuous passage of the current generated by it to fire the fuze in the mine4 ,in the case of a platinum wire fuze being in the circuit1 plenty of power may be given to the battery without fear of a premature explosion from this cause1 but in the case of a high tension fuze it is necessary to be very careful in order to guard against such a contingency4 ,as in the case of a signalling or shutter battery1 the electric current will be continually flowing1 it is necessary to employ a constant battery1 or one that requires least trouble and expense to maintain it in working order1 and it is for this reason that a modified form of ,daniell battery has been adopted to work the shutter apparatus4 ,daniell ,signalling ,battery4--,at ,fig4 #ge is shown the manner of arranging a ,daniell cell4 ,a glass or porcelain vessel a contains a saturated solution of sulphate of copper1 in which is immersed a copper cylinder b open at both ends and perforated by holes2 at the upper part of this cylinder there is an annular shelf d1 also perforated by holes1 and below the level of the liquid2 this is for the purpose of supporting crystals of sulphate of copper for the replacing of that decomposed as the electrical action proceeds4 ,inside the cylinder b is a thin porous vessel c of unglazed earthenware2 this contains either water1 or a solution of common salt1 or dilute sulphuric acid1 in which is placed the cylinder of amalgamated zinc e4 ,two strips of copper p and n1 fixed by binding screws to the copper and to the zinc1 serve for connecting the elements in series1 or otherwise4 ,for the purposes of testing1 either the ,leclanch or ,daniell battery specially arranged1 or the ,menotti battery1 which is really a modification of the ,daniell1 may be used4 ,illustration3 ,,firing ,,batteries1 ,,testing ,,batteries4 ,,plate ,,xix ,description of a ,menotti ,cell4--,a ,menotti cell1 shown at ,fig4 #gf1 consists of a copper cup containing some crystals of sulphate of copper and covered with a fearnought diaphragm a1 placed at the bottom of an ebonite cell b2 over this cup is put some sawdust1 and resting on top of this is a disc of zinc c on another piece of fearnought4 ,the upper portion of the zinc and its connection with the insulated wire are carefully insulated4 ,fresh water poured on the sawdust renders the battery active4 ,description of a ,menotti ,test ,battery4--,fig4 #gg represents a plan of the top of such a test battery with a #bj-ohm galvanometer attached thereto4 ,the connections are made as follows3-- ,one of the wires w of the object to be tested is attached to the terminal f1 which is also connected by an insulated wire to the copper cup a2 the other main wire w#a is attached to the terminal g of the galvanometer2 h1 the other terminal of the galvanometer1 is connected by a short piece of wire k to the terminal l of the contact key m2 and the contact point n is in connection with the zinc plate c2 thus the current from the battery flows along the wire w through the object to be tested1 back along the wire w#a1 through the coils of the galvanometer1 along the wire k to the contact key m1 and if this is pressed down to the zinc plate c1 so completing the circuit4 ,to steady the needle of the galvanometer a bar magnet is used1 which is inserted in the space r4 ,the whole of the apparatus is enclosed in a leathern case fitted with a cover and strap4 ,this is a very compact and simple form of test battery1 and will be found extremely useful in boats1 c41 when placing mines in position4 ,telegraph ,battery4--,for the purposes of telegraphing between torpedo stations1 c41 a form of ,leclanch battery1 known as ,no4 #c commercial pattern1 is generally used4 ,voltaic ,batteries4--,the following points in connection with the use of voltaic batteries1 which are taken from ,beechey's ',electro ,telegraphy1' should be carefully observed3-- #a4--;,each cell of a battery should be carefully insulated4 #b4--,the floors and tables in the battery room should be kept scrupulously clean and dry1 so as to prevent the least leakage or escape of the current4 #c4--,the plates of a battery should be clean4 #d4--,porous cells should be examined1 and cracked ones replaced4 #e4--,no sulphate of zinc or dirt should be allowed to collect at the lips of the cells4 ,in the case of a ,daniell battery-- #a4--,the solutions should be inspected daily1 and crystals of sulphate of copper added as required4 #b4--,the zinc plate must not touch the porous cell1 or copper will be deposited on it 7the zinc74 #c4--,the battery should be charged with sulphate of zinc from the first4 #d4--,the copper solution must be watched and prevented from rising over the edge of the porous jar1 the tendency of such solutions being to mix with each other by an action termed osmosis4 ,these being in addition to foregoing general directions for ,voltaic batteries4 ,defects in a ,voltaic ,battery on its ,current becoming ,deficient4--,on the electric current of a ,voltaic battery becoming deficient1 the following defects should be looked for3-- #a4--,solutions exhausted2 for instance1 sulphate of copper in a ,daniell's entirely or nearly gone1 leaving a colourless solution4 #b4--,terminals or connections between the cells corroded1 so that instead of metallic contact there are oxides of almost insulating resistance intervening in the circuit4 #c4--;,cells empty1 or nearly so4 #d4--;,filaments of deposited metals stretching from electrode 7pole7 to electrode 7pole74 ,also intermittent currents are sometimes produced by loose wires or a broken electrode1 which alternately makes and breaks contact when shaken4 ,inconstant currents are also sometimes produced when batteries are shaken4 ,the motion shakes the gases off the electrodes1 thus increasing temporarily the electro-motive force of the battery4 ,firing ,keys and ,shutter ,apparatus4--,the following is a description of the various firing keys and shutter signalling apparatus1 which is used in connection with a system of electrical submarine mines4 ,by means of the former the firing or other batteries may be thrown into circuit at will1 whilst by means of the latter the firing battery is thrown in circuit without the aid of an operator1 and a signal at the same instant given1 indicating that a certain mine of the system has been struck4 ,description of a ,series of ,firing ,keys4--,at ,fig4 #gh is shown a plan and section of a series of firing keys as arranged for firing several mines by observation4 ,it consists of a strong wooden frame a1 of a convenient form for the purpose of attaching it to the firing table by screws through the holes b1 b4 ,on this frame a series of keys c1 c1 c are fixed at convenient intervals4 ,these consist of a strong brass spring firmly screwed to a series of brass plates d1 d1 d on the front of the wooden box a4 ,from these latter short copper wires pass through the woodwork1 and of such a length that1 when required1 the mine wires may be easily attached by means of binding screws1 as shown at f4 ,the inner end of each key is fitted with an ebonite knob 7which is shown at c in the section7 to insulate the hand of the operator when using the key4 ,on the frame1 and directly under each of the ebonite knobs1 are arranged a series of metallic points g1 g1 g1 so placed that on either of the keys c being pressed down1 a perfect contact is made between it and its respective metallic point2 h1 h1 h are copper wires leading from the metallic points g1 g1 g through the box1 and of such a length that binding screws f1 f1 f can be easily attached to them when necessary4 ,a single firing key of an improved form is shown at ,fig4 #gi4 ,it consists of a strong wooden box a a1 weighted at the bottom with lead in order to steady the key on the table1 c41 on which it may be placed2 on the inside of the bottom of the box is fixed a piece of ebonite1 by which means the metallic point b1 and the terminal of the firing key c1 are insulated from each other2 d d' are two terminals at the end of the box1 to which the circuit wires are attached1 one of these terminals is connected in metallic circuit to the firing key at c1 the other one to the metallic point b2 a wooden cover h1 fitted with a catch k1 protects the connections of the wires2 by means of a plate1 and catch e e1 the key can be rendered inactive1 thus preventing the danger of a premature closing of the electric circuit2 by means of a spring s a break is always established between the key and the metallic point4 ,it is immaterial to which of the two terminals d d' either wire is connected4 ,the ,morse ,firing ,key4--,this form of key is so well known in connection with the ,morse telegraph1 that it is not necessary to describe it4 ,it is usually employed in torpedo work in connection with a testing and firing table4 ,the ,shutter ,apparatus4--,the shutter signalling and firing apparatus was devised to enable the firing battery current to be thrown in circuit without the aid of a personal operator1 the signalling current 7which is always kept in circuit7 at the same instant ringing a bell1 by which is known the particular mine that has been struck4 ,at ,fig4 #hj is represented a diagram of such an apparatus4 a is an armature working on a pivot between the two horns of an electro magnet b b1 and held in position by a spiral spring c2 the latter is in connection with a regulating screw1 by which more or less pressure may be brought to bear in an opposite direction to that of the attractive action of the electro magnet4 ,a stud i regulates the distance to which the armature may be drawn back2 d is a shutter on which a reference number for each mine should be indicated1 attached to a lever pivoted at the point e1 the inner arm of which is just long enough to catch under the point of the armature a2 when a current of sufficient strength is passed through the coils b b of the electro magnet1 the armature a is attracted1 releasing the lever attached to the shutter d1 which by its own weight falls into the position shown by the dotted lines4 f and g are two mercury cups1 the former being in connection with the signalling current1 and the latter with the firing current4 ,when the lever is horizontal and the shutter drawn up and ready for action1 the circuit of the signalling battery s is completed through the mercury cup f1 along an arm h of the lever to the pivot e1 and thence to the mine by the line wire w4 ,when the circuit closer is struck by a passing vessel1 and consequently the shutter thrown into the position shown by the dotted lines1 another arm k1 a prolongation of the lever1 falls into the mercury cup g1 which latter is in connection with the firing battery ,f4 ,the armature a is prevented from coming into actual contact with the horns of the electro magnet by two small studs4 ,the object of this is to prevent any effect of residual magnetism which might otherwise interfere with the rapidity of action of the armature when released and drawn back by the spring c4 ,illustration3 ,,firing ,,keys1 ,,shutter ,,apparatus4 ,,plate ,,xx ,the object of employing ,mercury ,cups4--,mercury cups were devised in the place of the springs used in connection with the original design of a shutter apparatus1 for the reason that electrical circuits dependent on the pressure of springs are always liable to interruption from dirt or oxide intervening between the points of contact4 ,shutter ,apparatus used with a ,circuit ,breaker4--,when the circuit breaking system is used with the shutter signalling apparatus1 the action of the armature in releasing the lever must be reversed2 that is to say1 that when the current is passing and the armature a attracted to the electro magnet b b1 the shutter d must be held up1 and when the current ceases1 and the armature a drawn back by the spring c1 the lever must be released1 and the shutter allowed to fall4 ,this is effected by altering the end of the lever1 so that it hooks into1 instead of abutting against the armature a4 ,to each shutter apparatus an electric bell is fitted1 by which notice is given when a circuit closer has been struck4 ,for general service1 a box containing seven such shutter signalling and firing apparatus has been adopted1 a plan of which is represented at ,figs4 #ha1 #hb and #hc4 ,the connections of the different circuits are as follows3-- ,the insulated wire of the upper bobbin of the electro magnet is connected to the spring of the armature2 the pivot of the lever is connected with the right-hand terminal ,b1 or main line connection on the top of the box2 the insulated wire from the lower bobbin is connected to the middle brass plate k in the front ledge of the apparatus1 the circuit from ,b to k being thus completed4 ,the front adjoining brass plate ,a1 provided with a terminal1 is connected with the negative pole of the signalling battery1 the positive pole being put to earth4 ,on a brass plug being put in the hole l1 the signalling current will flow to the plate k1 thence through the lower and upper bobbin to the spring of the armature1 along the latter to the shutter lever1 and from the pivot through the main line wire to the mine4 ,the innermost brass plates ,h ,h are all connected in the same metallic circuit1 and to them are attached by means of the binding screw ,d the test battery and galvanometer4 ,thus on the brass plug being removed from l1 and placed in m1 the signalling battery is cut out of circuit1 and the test battery thrown in4 ,in this way the condition of each individual mine may be ascertained while the connections of the remaining mines are left undisturbed4 ,the positive pole of the firing battery 7the negative being to earth7 is connected to the terminal ,s at the right-hand corner of the lower ledge of the box2 the plate to which the terminal ,s is fixed is divided at ,g1 the left-hand portion being connected to a bar which runs horizontally the whole length of the box1 and in metallic connection with each mercury cup g1 ,fig4 #hj4 ,a brass plug is placed in the hole ,g1 and when from any cause the lever drops1 the firing battery will be thrown into circuit1 and the mine to which the lever that has fallen is attached will be exploded4 ,shutter ,instrument and ,observing ,telescope4--,each mine is given a number1 which is put on the disc of the shutter instrument connected to it1 and also on the corresponding tablet ,c4 ,from the brass plate in connection with the spring c1 ,fig4 #hj1 a wire is taken to the terminal f1 ,fig4 #ha1 on top of the box4 ,from this terminal a wire is led to the connections of the observing telescope1 and thus the mines can be fired by judgment if required1 without the aid of the circuit closer4 ,the signal battery current is always circulating1 even when the system is in a state of rest1 but in consequence of the resistance placed in this circuit1 which may be either a resistance coil in the circuit1 added to the resistance of the fuzes1 when high tension fuzes are used1 or only the former resistance in the case of low tension fuzes1 this current is too feeble to form an electro magnet2 directly1 however1 a circuit closer is struck1 this resistance is cut out1 and thus the signal battery current becomes sufficiently powerful to work the electro magnet of that particular mine4 ,the circuit of the signal battery1 and that to the observing telescope1 are broken the instant the lever commences to fall4 ,to enable the apparatus to be used on the circuit breaking system1 a spare lever ,e is provided for that purpose with each box4 ,the object to be gained by a system of testing is to ascertain the condition of the electrical submarine mines placed in the defence of a harbour1 c41 and should there exist any fault1 not only to detect its exact position and cause1 but also its magnitude1 so that it may be at once determined whether it is necessary to remedy the fault1 or whether the electrical apparatus is sufficiently powerful to overcome the defect4 ,tests4--,there are two distinct kinds of tests1 viz43-- #a4--,mechanical tests4 #b4--;,electrical tests4 ,illustration3 ,,shutter ,,apparatus4 ,,plate ,,xxi ,mechanical tests are applied to ascertain that the mechanical arrangements of the shutter apparatus1 circuit closers1 and all similar appliances work efficiently and easily2 that the several parts of the mine case when put together for service are thoroughly watertight2 that the chains1 wire cables1 and ropes in connection with the mooring apparatus are of sufficient strength to perform the work required of them2 that the weights of the anchors1 or sinkers1 are such as to keep the mines in position after submersion2 and that the case of the mine be sufficiently strong to enable it to bear the external pressure due to the depth at which it may be submerged for a considerable time without any leakage4 ,the foregoing tests of the mine case and moorings would of course be performed during the process of manufacture1 but to prevent any chance of failure they should be repeated before being employed on actual service4 ,electrical ,tests4--,electrical tests are those which are applied to the several component parts of the system1 to ascertain that the electrical conditions necessary to a successful result exist4 ,the importance of being able to carry out the above in its entirety is understood when it is remembered that a submarine mine becomes practically valueless unless it acts efficiently at the single instant of time that it would be required so to do4 ,list of ,instruments used in ,testing4--,the following are some of the instruments that are employed in connection with a system of electrical tests3-- #a4--,thomson's electrometer4 #b4--,thomson's reflecting galvanometer4 #c4--;,astatic galvanometer4 #d4--;,differential galvanometer4 #e4--;,detector galvanometer4 #f4--,three coil galvanometer4 #g4--,thermo galvanometer4 #h4--,siemens's universal galvanometer4 #i4--;,a shunt4 #aj4--;,commutator4 #aa4--,rheostat4 #ab4--,resistance coils4 #ac4--,wheatstone's balance4 ,electrometers indicate the presence of a statical charge of electricity1 by showing the force of attraction or repulsion between two conducting bodies placed near together4 ,this force depending in the first place on the quantity of electricity with which the conducting bodies are charged1 ultimately depends on the difference of potential between them2 an electrometer is therefore strictly an instrument for measuring difference of potential4,j ,sir ,william ,thomson's quadrant electrometer is the most perfect form of electrometer yet constructed1 and the one usually employed in cable testing4 ,it consists of a very thin flat aluminium needle spread out into two wings1 and hung by a wire from an insulated stem inside a ,leyden jar1 which contains a cupful of strong sulphuric acid1 the outer surface of which forms the inner coating of the ,leyden jar4 ,a wire stretched by a weight connects the aforesaid needle with this inner coating4 ,a mirror1 rigidly attached to this needle by a rod1 serves to indicate the deflection of the needle by reflecting the image of a flame on to a scale4 ,the needle hangs inside four quadrants1 which are insulated by glass stems3 each pair of opposite quadrants are in electrical connection4 ,above and below the quadrants two tubes1 at the same potential as the needle1 serve to screen it and the wires in connection with it from all induction except that produced by the four quadrants4 ,suppose the needle charged to a high negative potential 7-71 then if the quadrants are symmetrically placed1 it will deflect neither to the right nor to the left1 so long as the near quadrants are at the same potential4 ,if one of these be positive relatively to the other1 the end of the needle under them will be repelled from the negative quadrant to the positive one1 and at the same time the other end of the needle will be repelled from in the opposite direction4 ,this motion will be indicated by the motion of the spot of light reflected by the mirror1 and the number of divisions which the spot of light traverses on the scale measures in an arbitrary unit the difference of potential between the and - quadrants4 ,the reflecting electrometer being a very delicate instrument1 requires careful handling1 and should only be used by a practised electrician4 ,its use would therefore be restricted to important stations1 and special tests of a delicate nature4 ,thomson's ,reflecting ,galvanometer4--,a galvanometer is an instrument intended to detect the presence of a current and measure its magnitude4 ,the most sensitive galvanometer as yet constructed is the reflecting galvanometer of ,sir ,william ,thomson1 a diagram of which is shown at ,fig4 #hd4 ,a small piece of magnetised steel watch spring1 #c_/hths of an inch long1 is fastened with shellac on the back of a little round concave mirror1 and of about the size of a fourpenny piece4 ,this is suspended by a piece of unspun silk thread in the centre of a coil of many hundred turns of fine copper wire insulated with silk1 and well protected between the turns with varnish4 ,the two ends of the coils are soldered to terminal screws a1 b1 so that any conducting wire can be joined up to it as required4 ,the little mirror hangs in the middle of its coil1 with the magnet lying horizontally4 ,by means of a lamp ,l placed behind the screen1 the light of which passes through a slit ,m1 and is thrown on the face of the mirror1 a spot of light is reflected on the scale ,n4 ,when a current passes through the coil1 the little magnet is deflected1 and since the magnet is attached to the mirror1 which is very light1 both are deflected as forming one body1 and the spot of light moves accordingly along the scale ,n4 ,a powerful steel magnet ,s is placed above the coil1 and can be moved up or down1 whereby the directive force of the earth may be increased or weakened4 ,this magnet ,s is used to steady the spot of light1 which otherwise would shake about1 and there would be no certainty about the measurement4 ,a second magnet ,t is placed perpendicular to the magnetic meridian1 to adjust the zero of the instrument1 i4e41 to bring back the spot of light to a fiducial mark at the centre of the scale when no current is passing4 ,this instrument should only be used at important stations1 and when special tests of a delicate nature are required to be applied4 ,astatic ,galvanometer4--,an astatic galvanometer is that in connection with which an astatic needle is employed1 by the use of which the sensitiveness of a galvanometer is greatly increased4 ,an astatic needle is a combination of magnetised needles with their poles turned opposite ways4 ,at ,fig4 #he a diagram of such an instrument is shown4 ,two magnets ,d and ,c are joined1 with the north pole of one over the south pole of the other1 forming one suspended system4 ,in the ordinary form of astatic galvanometer the needles ,d and ,c are about two inches long1 and are each covered by a coil1 these latter being so joined that the current must circulate in opposite directions round the two so as to deflect both magnets similarly4 ,the deflection of the needles ,d and ,c is observed by means of a pointer or glass needle ,a1 ,b1 rigidly connected with the astatic system by a prolongation of the brass rod connecting the needles ,d and ,c4 ,the coils are flat and of the shape indicated in ,fig4 #he1 and are also made in two halves1 placed side by side with just sufficient space between them to allow the rod to hang freely4 ,this form of galvanometer1 though less delicate than the preceding one1 is still a very sensitive one1 and should only be applied in the case of fine and delicate tests4 ,differential ,galvanometer4--,a differential galvanometer consists of a magnetic needle surrounded by two separate coils of equal length and material carefully insulated from each other and wound in opposite directions4 ,in using it one circuit acts against the other4 ,if a current of equal strength were passing through each there would be no deflection of the needle1 because the influence in both directions is equal4 ,if one current were stronger than the other1 the needle would be deflected by the stronger4 ,this form of galvanometer will be found extremely useful in connection with a system of electrical tests4 ,latimer ,clark's double shunt differential galvanometer is the instrument best adapted for submarine mine tests4 ,detector ,galvanometer4--,a detector galvanometer is usually made with a vertical needle1 and is employed to detect and roughly estimate the strength of a current where no particular accuracy is required4 ,it consists of a magnetic needle pivoted in the centre of a coil of insulated wire1 and having an index needle attached to move with it1 the latter appearing on a dial1 divided into #cfj equal arcs or portions3 a diagram of such an instrument is shown at ,fig4 #hf4 ,this instrument should be of small size and portable form1 and as sensitive as it is possible to make it1 under such conditions4 ,three ,coil ,galvanometer4--,the three coil galvanometer is provided with a vertical needle1 and is in other respects very similar in appearance to the detector galvanometer before described4 ,it is formed with three coils of #b1 #aj1 and #ajjj ohms resistance2 each coil is connected with a brass plate on the top of the box which encloses the whole1 and may be switched into circuit by means of a plug at will4 ,the object of the three resistances is to suit the different resistances that may occur1 with a perfect1 or imperfect state of the electrical combination in connection with each mine4 ,a diagram of this instrument is shown at ,fig4 #hg1 the dotted portions are inside the case4 ,thermo ,galvanometer4--,a thermo galvanometer is an instrument used to ascertain the power of a firing battery which is employed to ignite platinum wire or low tension fuzes4 ,the form of thermo galvanometer generally used in connection with a test table1 is arranged as follows3-- ,two ebonite studs1 fitted with brass connecting screws1 are fixed to the lid of a box containing some resistance coils1 and placed in circuit with them2 these studs1 placed about #c of an inch apart1 are arranged to receive a piece of platinum wire which is stretched from one stud to the other2 the firing battery being placed in circuit with the platinum wire1 and the resistance coils1 its working power would then be tested by the fusion of the wire through a given electrical resistance1 as indicated by the resistance coils put in circuit4 ,another form of thermo galvanometer1 which is very compact and portable1 is shown at ,fig4 #hh4 ,it consists of a wooden box a1 with a cover of ebonite b1 within the box is placed a resistance coil c2 d and e are two ebonite standards #c apart1 the former of which is connected by a copper wire with the terminal f1 the latter to the terminal g2 the terminal h is similarly connected to the contact piece k1 and the terminal l to the firing key m1 at n2 the resistance coil c is connected to the terminal g and to the copper wire n2 the platinum wire 7of which several lengths are used1 according to the resistance of the coil c7 is placed between the standards d and e4 ,to test a battery1 it is only necessary to connect it to the terminals f and h1 when by pressing down the key m the power of the battery1 according as to its fusing or not the platinum wires1 will be ascertained2 the use of the terminals g and l is to cut out the resistance1 which is effected by connecting them by means of a copper wire4 ,siemens's ,universal ,galvanometer4--,siemens's universal galvanometer is an instrument combining in itself all the arrangements necessary for the following operations3-- #a4--;,for measuring electrical resistances4 #b4--;,for comparing electromotive forces4 #c4--;,for measuring the intensity of a current4 ,the instrument which is shown in elevation and plan at ,pl4 xxiii41 ,figs4 #a and #b respectively1 consists of a sensitive galvanometer which can be turned in a horizontal plane1 combined with a resistance bridge 7the wire of which bridge instead of being straight is stretched round part of a circle74 ,the galvanometer has an astatic needle1 suspended by a cocoon fibre1 and a flat bobbin frame wound with fine wire4 ,the needle swings above a cardboard dial divided in degrees2 as however1 when using the instrument the deflection of the needle is never read off1 but the needle instead always brought to zero1 two ivory limiting pins are placed at about #bj degrees on each side of zero4 ,the galvanometer is fixed on a graduated slate disc1 round which the platinum wire is stretched4 ,underneath the slate disc three resistance coils of the value of #aj1 #ajj1 and #ajjj ,siemens' units are wound on a hollow wooden block1 which protrudes at one side1 and on the projection carries the terminals for the reception of the leading wires from the battery and unknown resistance4 ,the adoption of three different resistance coils enables the measuring of large as well as small resistances with sufficient accuracy4 ,illustration3 ,,galvanometers ,,for ,,testing4 ,,plate ,,xxii ,the whole instrument is mounted on a wooden disc1 which is supported by three levelling screws1 so that it may be turned round its axle4 ,on the same axle a lever is placed which bears at its end an upright arm1 carrying a contact roller4 ,this roller is pressed against the platinum wire round the edge of the slate disc by means of a spring acting on the upright arm1 and forms the junction between the ,a and ,b resistances of a ,wheatstone's bridge1 which resistances are formed by the platinum wire on either side of the contact roller1 one of the three resistance coils forming the third resistance of the bridge4 ,g is the galvanometer1 k a milled head from which the needles are suspended1 and by turning k they can be raised or lowered1 m is the head of a screw which arrests or frees the needle when in motion4 h#a1 h#b1 h#c1 h#d1 are the terminals of the respective ends of the three resistance coils1 viz41 #aj1 #ajj1 and #ajjj units1 which are wound on the wooden block ,c2 these terminals may be connected to each other by means of stoppers1 and therefore one or more of the resistances may be brought into circuit as desired1 and to the ends of these terminals the wires of the artificial resistances are connected as shown on diagrams ,pl4 xxiv41 ,figs4 #a1 #b1 #c;a and #c;b2 f is the graduated slate disc1 round which the platinum wire is stretched in a slight groove at the edge of the disc1 and is inserted in such manner that about half its diameter protrudes beyond the slate4 ,the ends of the platinum wire are soldered to two brass terminals l and l#a1 which are placed at the angles formed by the sides of the gap in the slate disc1 and which form the junctures1 as in the ordinary resistance bridge1 between ,a1 n1 and the galvanometer on one side1 and ,b1 ,x1 and the galvanometer on the other side1 of the parallelogram4 ,the terminal l is permanently connected by a thick copper wire or metal strip to terminal h#a1 and the other terminal l#a is connected in a similar manner to terminal ,,iii4 ,slate is adopted for the material of which to make the disc f1 because it is found by experience to be the material which is the least sensitive to variations in the weather or temperature4 ,the slate disc is graduated on its upper edge through an arc of #cjj degrees1 zero being in the centre1 and the graduations figured up to #aej on each side at the terminals l and l#a of the bridge wire4 ,in the centre of the circular plate ,e of polished wood1 supported upon three levelling screws b1 b1 b1 a metal boss is inserted1 in which turns the vertical pin a which carries the instrument4 ,this pin1 being well fitted to the boss1 supports the instrument firmly1 but at the same time allows it to be turned freely round its vertical axis without losing its horizontal position when once obtained4 ,on the arm ,d ,d1 which turns on the pin a1 and somewhat behind the handle g1 there is a small upright brass arm d turning between two screw points r1 and carrying in a gap at its upper end a small platinum jockey pulley e turning on a vertical axis4 ,this pulley forms the movable contact point along the bridge wire1 against which it is kept firmly pressed by means of a spring acting on the arm d4 ,the arm ,d ,d1 which is insulated from the other parts of the apparatus1 is permanently connected with the terminal ,i4 ,on the top of d a pointer ,z or a vernier is fixed1 which laps over the upper edge of the slate disc and points to the graduations4 ,to the pin a is attached a circular disc of polished wood ,c1 about one inch thick1 and having a groove turned in its edge for the reception of the insulated wires composing the resistances4 ,the disc ,c has a projection c1 which carries the five insulated terminals marked ,i41 ,,ii41 ,,iii41 ,,iv41 ,v41 as shown on ,figs4 #a and #b1 ,pl4 xxiii4 ,terminals ,,iii4 and ,,iv4 can be connected by a plug1 ,,ii4 and ,v4 by the contact key ,k4 ,terminal ,i4 is in connection with the lever ,d ,d4 ,figs4 #c and #d1 ,pl4 xxiii4 show the shunt box supplied with the galvanometer if specially desired2 the copper connecting arms a1 a are screwed to the terminals ,,ii4 and ,,iv4 ,by inserting a plug at c 7,fig4 #d1 ,pl4 xxiii471 the galvanometer is put out of circuit altogether1 whilst by plugging either of the other holes shunts of the value of #a_/i1 #a_/ii1 or #a_/iii1 are introduced into the circuit1 and the effect upon the galvanometer is reduced to #a_/aj1 #a_/ajj1 #a_/ajjj1 respectively of what it would have been without the insertion of the shunt4 ,figs4 #e and #f1 ,pl4 xxiii41 show a battery commutator allowing to bring into the circuit four different amounts of battery power4 ,it is placed in the battery circuit whenever consecutive tests with different batteries are desired to be made1 it being only necessary to change the place of the stopper in the battery commutator1 the terminal screw a of the battery commutator being connected to terminal ,v4 of the galvanometer1 and the screws b1 b1 b1 b to various sections of the battery3 see diagram of connections1 ,fig4 #d1 ,pl4 xxiv4 ,the application of the universal galvanometer will be clear from the diagrams on ,pl ii42 instructions1 however1 for its practical use are added further on1 and also tables for use when measuring conducting resistances4 ,as will be seen from diagram1 ,fig4 #a1 ,pl4 xxiv41 the proportion between the unknown resistance ,x1 and the artificial resistance n is1 when the deflection is read off on the side of the slate disc marked ,a3 ,x 3 n #aej a 3 #aej - a or1 ,x 77#aej a7 _/ 7#aej - a77 n4 but if read off on the ,b side of the disc-- ,x 77#aej - a7 _/ 7#aej a77 n4 ,the values of these two fractions1 for every half degree1 will be found in the columns headed ,a and ,b of the table in the ,appendix4 ,illustration3 ,,siemen',s ,,universal ,,galvanometer4 ,,plate ,,xxiii ,illustration3 ,,siemen',s ,,universal ,,galvanometer4 ,,plate ,,xxiii,a ,illustration3 ,,siemen',s ,,universal ,,galvanometer4 ,,plate ,,xxiv ,illustration3 ,,siemen',s ,,universal ,,galvanometer ,,plate ,,xxiv,a ,measuring ,electrical ,resistances4--,for this purpose the instrument is arranged as a ,wheatstone's balance4 ,the connections are made as shown at ,pl4 xxiv41 ,figs4 #a and #e1 where ,x is the unknown resistance4 a4--,the needle i is to be brought to the zero point of the small cardboard scale by turning the galvanometer ,g round its vertical axis1 taking care that the needle moves with perfect freedom4 b4--,the pointer or vernier ,z is to be brought1 by means of the handle g1 to the zero point of the large scale on the slate disc4 c4--,a plug is to be inserted between the terminals marked ,,iii4 and ,,iv4 d4--,the holes #aj1 #ajj1 and #ajjj are1 two of them1 to be plugged1 and one left open1 according to the extent of the unknown resistance to be measured2 either #aj or #ajj must be left open if the resistance is small1 and #ajjj if it is large4 e4--,the two ends of the unknown resistance are to be connected to terminals ,,ii4 and ,,iv4 f4--,the two poles of some galvanic battery are to be connected to terminals ,i4 and ,v4 ,when the above-mentioned connections have been made1 and on depressing the key ,k1 the battery current is sent into the combination and deflects the needle1 say1 to the right-hand or ,b side of the instrument1 the pointer or vernier ,z must then be pushed1 by means of the handle g1 to the ,b side of the instrument4 ,if this is found to increase the deflection of the needle i1 the pointer ,z should be pushed to the other or ,a side of the instrument beyond the zero point of the large scale until the needle remains stationary when the key ,k is depressed4 ,the number indicated by the vernier ,z should be read off carefully1 and notice taken whether it is on the ,a or ,b side of the large scale4 ,this number must then be referred to the galvanometer table1,k when the figure opposite to the number1 multiplied by the resistance unplugged1 is the resistance of ,x4 ,the value of the resistance to be determined will be thus found by a single operation4 ,supposing the reading to be #ej on the ,a side of the large scale1 the resistance n unplugged having been #ajj units1 we get according to the before-mentioned law of resistance bridge the following proportion 7see ,fig4 #e1 ,pl4 xxiv473-- ,x 3 #ajj #aej #ej 3 #aej - #ej ,x 77#aej #ej7 _/ 7#aej - #ej77 #ajj ,x #bjj units4 ,for measuring very small resistances a single cell will be found sufficient2 but for large resistances more should be used1 say1 #ae to #bj4 ,if very accurate measurements of small resistances are to be taken1 the screw at the end of the moving arm ,d ,d should receive one battery wire1 terminal ,v4 receiving the other4 ,comparing ,electromotive ,forces4--,for this purpose ,professor ,e4 du ,bois-,reymond's modification of ,poggendorff's compensation method is used4 ,the connections are made as shown at ,pl4 xxiv41 ,figs4 #b and #f4 ,for comparing two electromotive forces ,e#a and ,e#b1 a third electromotor of higher electromotive force ,e#j is used1 and two separate tests taken4 ,the manipulations a and b are to be the same as before4 c4--,the hole between ,,iii4 and ,,iv4 to be left unplugged4 d4--,plugs to be inserted in #aj1 #ajj and #ajjj4 e4--,the two poles of the electromotor of an electromotive force ,e#j are to be connected to the terminals ,,iii4 and ,v4 f4--,the poles of the battery whose electromotive force ,e#a is to be compared are connected to terminals ,i4 and ,,iv4 in such a manner that the similar poles of the two electromotors are joined to terminals ,i4 and ,,iii41 and to ,,iv4 and ,v4 respectively4 ,when depressing the key ,k the galvanometer needle will be deflected and can be brought back to zero by turning the pointer ,z either to the right or to the left4 ,should for instance the pointer have to be brought to #cj on the ,a side we have the following equation-- ,e#a ,e#j 77#aej - #cj7 _/ 7 #cjj n77 7#a71 where n is the resistance of the battery ,e#j4 ,the electromotor ,e#b is now to be inserted in the place of ,e#a1 and the galvanometer needle1 when it deflects1 again brought back to zero by moving the pointer ,z4 ,if for instance the pointer has to be pushed to #dj on the ,b side to obtain equilibrium we have-- ,e#b ,e#j 77#aej #dj7 _/ 7 #cjj n77 7#b74 ,by eliminating n from equations #a and #b we have ,e#a 3 ,e#b 7#aej - #cj7 _/ 7#aej #dj7 #ab 3 #ai 7#c74 ,the two electromotive forces are in the same proportion as the two observed distances of the pointer ,z from #aej on the ,a side of the instrument4 ,for measuring the ,intensity of a ,current4--,for this purpose the instrument is simply used as a sine galvanometer4 ,the connections are made as shown at ,pl4 xxiv41 ,figs4 #c;a and #g4 ,the manipulations a1 b1 c1 and d same as in the second case4 e4--,connect one pole of a battery to terminal ,,ii4 and put the other pole to earth4 f4--,connect the line to terminal ,,iv4 ,the galvanometer is then to be turned in the same direction as the needle is deflected until the needle coincides with the zero point4 ,whilst this is being done the large scale on the slate disc will move under the pointer ,z1 which must be left stationary2 the sine of the angle indicated by ,z will thus give the value proportionate to the strength of the current4 ,should the shunt box be required1 it has to be connected with terminals ,,ii4 and ,,iv4 ,fig4 #d shows the same connections as ,fig4 #g1 but without the shunt box1 and with the battery commutator4 ,fig4 #c;a shows diagram of the same connections but with the key ,k1 and ,fig4 #c;b the same without the key4 ,a ,shunt4--,a ,shunt is a second path offered to a current traversing a given circuit1 or portion of a circuit1 so as to diminish the amount of the current flowing through that portion of the circuit4 ,in the diagram shown at ,fig4 #hi the shunt diminishes the amount of the current flowing along the circuit between ,a and ,b4 ,if only #a_/,nth of the current is to pass along the circuit between ,a and ,b 7of resistance ,r7 then the resistance of the shunt must equal ,r_/7,n - #a74 ,by the aid of shunts it is quite possible to make use of very sensitive instruments to measure powerful currents4 ,commutators or ,switch ,plates4--,a commutator or switch plate is an apparatus by which the direction of currents may be changed at will1 or by which they may be opened or closed4 ,bertin's commutator1 which is represented at ,fig4 #ij1 consists of a small base of hard wood on which is an ebonite plate1 this by means of the handle m is turned about a central axis between two stops c and c'4 ,on the disc are fixed two copper plates1 one of which o is always positive1 being connected by the axis and by a plate 77 with the binding screw ,p1 which receives the positive electrode of the battery2 the other copper plate i1 e1 bent in the form of a horse-shoe1 is connected by friction below the disc with a plate 7-71 which plate is connected with the negative electrode ,n4 ,on the opposite side of the board are two binding screws b1 and b'1 to which are attached two elastic metal plates r1 and r'4 ,on the disc being turned as shown in the figure1 the current coming by the binding screw ,p passes into the piece o1 the plate r1 and finally the binding screw b1 which by means of a copper wire leads the current to the apparatus in connection with b2 then returning to the binding screw b'1 the current reaches the plate r'1 the piece i1 e1 and so to the battery by the binding screw ,n4 ,if the disc is turned so that the handle m is half way between c and c'1 the pieces o and i1 e1 being no longer in contact with the plates r and r'1 the current will not pass4 ,if m is turned as far as c1 the plate o will then touch r'1 and the current pass to b'1 and return by b1 thus reversing its direction4 ,peg switches are also often used2 they are arranged so that the removal or insertion of a brass peg or plug cuts out1 or completes a circuit4 ,rheostat4--,a rheostat is an instrument used for the comparison of resistances4 ,illustration3 ,,shunt1 ,,commutator1 ,,rheostat4 ,,plate ,,xxv ,wheatstone's rheostat1 which is shown in elevation at ,fig4 #ia1 consists of two cylinders ,a and ,b1 one of brass and the other of non-conducting material1 so arranged that a copper wire can be wound off the one on to the other by turning a handle ,c4 ,the surface of the non-conducting cylinder ,b has a screw thread cut in it for its whole length1 in which the turns of the copper wire lie1 so that its successive convolutions are well insulated from each other4 ,two binding screws ,d1 ,d' connected with the ends of the copper wire are provided1 to which the circuit wires are connected4 ,a scale is attached at ,e1 by means of which the number of convolutions on ,b can be read off2 and parts of a revolution are indicated on a circle at one end4 ,the handle ,c can be shifted from one cylinder to the other4 ,supposing the rheostat introduced into a circuit1 and the whole of the copper wire wrapped on the metal cylinder ,a1 then1 on account of the large section of this metal cylinder1 its resistance may be entirely neglected1 but for every convolution of the wire on the non-conducting cylinder ,b1 a specific resistance is introduced into the circuit4 ,the amount of resistance can thus be varied as gradually as desired by winding on and off the cylinder ,b4 ,this instrument is often used in connection with the thermo galvanometer4 ,resistance ,box4--,the general arrangement of a resistance box is shown in the diagram ,fig4 #ib4 ,between two terminal binding screws ,t and ,t#a secured on a vulcanite slab are fixed a series of brass junction pieces a1 b1 c1 d2 each of these is connected by a resistance coil to its neighbour1 as shown at #a1 #b1 #c1 and #d4 ,a number of brass conical plugs with insulating handles of vulcanite are provided1 which can be inserted between any two successive junction pieces1 as between ,t and a1 or a and b4 ,with all the plugs inserted1 the electrical current will flow direct from ,t to ,t#a1 the large metallic junction pieces directly connected by the plugs would offer no sensible resistance2 but if all the plugs were removed1 then the current would flow through each of the coils #a1 #b1 #c1 and #d1 and the resistance in the circuit would be the sum of the resistances of those four coils4 ,with the plugs arranged as in the figure1 the current would flow through coil #d only1 and the resistance in the circuit would be equal to the resistance of that coil4 ,wheatstone's ,balance4--,the electrical conductivity of a body is determined by ascertaining the ratio between the resistance of a certain length of the conductor in question1 having a given section1 to that of a known length of a known section of some substance taken as a standard4 ,for this purpose ,wheatstone's bridge in connection with a box of resistance coils is the most convenient method4 ,at ,fig4 #id is shown ,wheatstone's balance 7,post-office pattern71 and at ,fig4 #ic the apparatus is reduced into the form of a parallelogram1 which is the usual diagram of ,wheatstone's bridge4 ,the theory of the bridge is as follows3 ,four conductors ,a ,b1 ,b ,c1 ,a ,d1 and ,d ,c are joined at ,a and ,c to the poles of a battery ,z2 the resistance between ,a and ,b is ,r2 that between ,a and ,d is r2 that between ,d and ,c is ,r#a2 and that between ,b and ,c is x1 the unknown resistance to be measured4 ,a convenient constant ratio is chosen for ,r#a and r1 such as equality #a to #aj1 #a to #ajj1 or #a to #ajjj2 and then ,r#a is adjusted until no current flows through the galvanometer ,g2 when this is the case we have ,r 3 r,r#a 3 x1 or x 7r_/,r7 ,r#a2 so that if r ,r_/#ajj1 x will be equal to ,r#a_/ajj4 ,two keys a and b are inserted2 the current is wholly cut off the four conductors until contact is made at a2 and then after the currents in the four conductors have come to their permanent condition1 contact is made at b to test whether any current flows through the galvanometer4 ,the three resistances ,r1 ,r#a and r and the resistance of the galvanometer should be small if x is small1 and great if x is great4 ,the conductors ,a ,b and ,a ,d of the bridge are each formed of three resistance coils having a resistance of #aj1 #ajj1 and #ajjj ohms respectively1 inserted between the terminals ,b and ,d of the balance1 ,fig4 #id4 ,the conductor ,d ,c is formed of a set of resistance coils from #a up to #djjj ohms1 amounting altogether to #aa1aaj ohms1 inserted between the terminals ,d and ,c of the balance2 in the balance1 a brass plug being inserted between the terminals ,d and ,d#a1 they may be considered as one terminal ,d4 ,the conductor ,b ,c is the wire to be tested1 and is connected to the terminals ,b and ,c of the balance4 ,measurement of ,resistances4--,when a resistance is to be measured that is within the range of the coils in ,r#a1 ,r and r are made equal4 ,the needle of the galvanometer will move in a different direction1 either to the right or to the left1 according as the resistance in ,r#a is greater or less than the line wire x4 ,the needle remains at zero only when the resistance in ,r#a is equal to that in x4 ,for r 3 ,r 33 ,r#a 3 x4 ,illustration3 ,,wheatstone',s ,,bridge4 ,,plate ,,xxvi ,when the resistance of x is greater than that of ,r#a1 as in an insulation test1 the resistance in r is made less than that in ,r1 in order that r and ,r may have such a proportion one to the other as will enable the coils in ,r#a to balance a resistance in x1 greater than their own1 that is to say1 greater than #aa1ajj ohms2 thus r 3 ,r 33 ,r#a 3 x1 or #aj 3 #ajjj 33 #aj1jjj 3 #a1jjj1jjj1 the resistance in the line to be tested would be #a1jjj1jjj ohms1 supposing the values of r1 ,r and ,r#a to be respectively #aj1 #ajjj1 and #aj1jjj ohms4 ,when the resistance to be tested is less than that of the least coil in ,r#a 7#a ohm71 then the resistance in r is made greater than in ,r4 ,thus r 3 ,r 33 ,r#a 3 x1 or #ajj 3 #aj 33 #b 3 #jb2 the resistance of the line to be tested would in this case be #a_/bj of an ohm4 ,manipulation4--,in all cases the key in connection with the battery should first be depressed1 then the galvanometer key1 making very short contacts by the latter1 just sufficient to show the direction of the deflection1 until the coils in ,r#a are nearly adjusted1 otherwise considerable time will be lost in making a series of tests1 owing to the swing given to the needle1 which will take some little time before it again remains steady at zero4 ,when once the coils in ,r#a are adjusted1 and a balance obtained1 it should be ascertained whether the needle will remain steady when contact is made and broken4 ,test ,tables4--,in connection with a system of testing electrical submarine mines1 for the sake of convenience and simplicity it is necessary to use a table 7termed a ,test ,table71 on which all the apparatus used for the purpose of testing are fixed4 ,several forms of tables have been designed for such a purpose4 ,at ,fig4 #ie is shown the method of arranging such a table4,l ,a is an astatic galvanometer placed between two switch plates1 ,b and ,c2 ten other similar switch plates1 #a1 #b1 #c1 #d1 ,d1 #e1 #f1 #g1 ,e1 and #h1 are arranged in front of the galvanometer ,a2 ,f1 ,g1 and ,h are three terminal plates2 ,k is a box of resistance coils used in connection with the thermo galvanometer ,m2 ,l is a firing key1 and ,n a battery commutator2 ,o is a three-coil galvanometer2 ,r is a ,wheatstone balance 7,post-office pattern74 ,the ten switch plates1 #a1 #b1 #c1 #d1 ,d1 c41 are used for the connection of any particular line to be tested1 as well as for the earth connections and instruments employed in that operation4 ,sea ,cell ,tests4--,the arrangement shown in the figure is that required in connection with the sea cell test1 and ,mr4 ,brown's method of keeping certain earth plates in a bucket instead of in the sea4 ,if two plates of suitable metal to form a ,voltaic battery are placed in salt water and connected by a metallic conductor1 a battery is at once formed capable of producing considerable deflection on a moderately delicate galvanometer4 ,testing by this arrangement has been termed the sea cell test4 ,arranging ,earth ,plates4--,mr4 ,brown's1 ,assistant-,chemist to the ,war ,department1 method of arranging the earth plates is as follows3-- ,a series of earth plates1 such as copper1 carbon1 tin1 zinc1 c41 are placed in a bucket filled with sea water1 and which is placed in the testing room4 ,the water in the bucket is put in connection with the water of the sea by means of a conducting wire1 terminating at one end with a zinc plate in the bucket1 and at the other with a zinc plate in the sea4 ,by this means the tests made with the different earth plates in the bucket are identical with those made with corresponding earths placed absolutely in the sea1 and therefore these latter may be done away with1 the sea cell tests being entirely carried out by means of the bucket earth plates4 ,in addition to the bucket earth plates there will be several other earth plates in connection with the testing room1 these being placed in the sea1 such as the zinc earth for the firing battery1 the zinc earth for the signalling battery1 c4 ,connections of ,switch ,plates4--,the switch plate ,d is used for the connection of any particular mine cable which it may be required to test4 ,the switch plate ,e is connected with a zinc earth plate used for testing the firing battery4 ,this must always be in the sea4 ,the switch plate #a is in connection with a zinc earth in the bucket2 #b is attached to a copper earth plate in the bucket2 #c is attached to a carbon earth plate in the bucket2 #d to a tin earth plate in the bucket2 #e is used for connection with the zinc signalling earth connection in the sea2 #f is attached to a copper earth plate used for the sea cell test1 or any other purpose required1 in the sea2 #g is attached to a zinc earth plate in the sea2 and #h is a common zinc earth in the sea4 ,the terminal plates ,g and ,h are used for the connection1 for testing purposes of the negative and positive poles1 of the firing battery1 and ,f is connected with a zinc earth in the sea1 for a similar purpose4 ,these plates are in connection with the resistance coils ,k and the thermo galvanometer ,m1 employed for testing the firing battery1 the circuit being closed by the firing key ,l4 ,other ways of using these plates may of course be adopted if desired4 ,the resistance coils ,k range from #je to #ajj ohms1 and are composed of wire adapted for the passage of a quantity current4 ,a reversing key is generally used in connection with a testing battery and the three-coil galvanometer ,o4 ,this reversing key would consist of two bridges completely insulated from each other1 the upper one attached to the negative1 the lower one to the positive pole of the test battery4 ,in their normal position both keys press against the upper bridge1 and until one or other of the keys is pressed down no current will pass1 the direction of the current being altered by pressing down a different key4 ,the point of each key is provided with a terminal and connected1 the one to a zinc earth through the switch plate #h1 the other to one terminal of the three-coil galvanometer when the tests are to be applied4 ,the ,wheatstone balance ,r is used in finding the resistances of electrical cables1 balancing fuzes1 c4 ,by means of a commutator1 ,n1 the necessary number of cells for any particular test may be thrown in circuit when required4 ,test of ,platinum ,wire ,fuze for ,conductivity4--,the platinum wire fuze may be tested electrically as follows3-- ,if placed in circuit with a few cells of a ,daniell or ,leclanch battery and a detector galvanometer1 before the platinum wire bridge of the fuze is fixed1 there should be no deflection of the needle1 for no metallic circuit exists2 if it did1 such would be fatal to the efficiency of the fuze4 ,if similarly placed in circuit after the bridge has been fixed1 a considerable deflection of the needle should result1 such deflection being due to the current passing through the metallic bridge1 which to be efficient ought to be the sole medium through which the circuit is completed4 ,test of ,resistance of ,platinum ,wire ,fuze4--,the electrical resistance of a platinum wire fuze is ascertained by means of the ,wheatstone's balance ,r and galvanometer ,a1 ,fig4 #ie4 ,the terminals of the fuze are connected to the binding screws of the balance1 the commutator ,n and galvanometer ,a being connected up in circuit4 ,the resistance of the coils is then adjusted by taking out plugs until the needle of the galvanometer ,a is brought to zero1 when the sum of the resistances indicated by the unplugged coils will be equal to that of the fuze4 ,the resistance of a platinum wire fuze might also be ascertained by means of a differential galvanometer instead of a ,wheatstone balance4 ,the electrical resistance of #c_/aj of fine platinum wire1 weighing #ai grains to the yard1 is #c_/aj of an ohm nearly 7,schaw74 ,testing ,high ,tension ,fuzes4--,high tension fuzes require very delicate and careful management in testing them1 due to the high electrical resistance of such fuzes1 which ranges from #aejj to #bjjj ohms1 combined with the danger of premature explosion when testing even with a small number of battery cells4 ,very sensitive galvanometers1 such as the reflecting galvanometer1 should if possible be used1 otherwise the mode of making the tests for conductivity and resistance of a high-tension fuze is similar to that already given for a platinum wire fuze4 ,detonating fuzes should always be placed in an iron case during the process of testing4 ,insulation ,test for ,electrical ,cables4--,to test an electrical cable for insulation1 it should first be put in a tank of water1 or in the sea1 and allowed to soak for at least forty-eight hours4 ,the object of this is to allow the water to penetrate the outer protection of hemp and iron wires1 c41 and to search out and get into any weak places there may be in the insulation under the armouring4 ,at ,fig4 #if is shown the method of performing this test4 ,a is a tank holding the electrical cable1 which has been in soak for forty-eight hours2 ,b is an astatic galvanometer2 ,c1 ,z a ,leclanch or ,daniell battery of great power2 and ,c is an ordinary firing key4 ,one end of the electric cable ,d is connected to the galvanometer ,b through the firing key ,c2 the other end of the cable is very carefully insulated2 one pole of the battery is connected to the galvanometer ,b1 the other is put to earth in the tank at ,f2 should the insulation be perfect1 no deflection of the needle should follow on the key being pressed down4 ,a very slight deflection might be observed on a moderately sensitive galvanometer1 due to the current passing through the insulation2 its whole length being immersed1 the surface through which such a current would pass would be large1 and the sum of the infinitesimally small quantities escaping over the whole length1 would in the aggregate be sufficient to deflect the needle to a small extent in completing the circuit of the battery4 ,should any considerable deflection occur1 it would indicate a defect or leak in the insulation of the cable1 the extent of which would be roughly measured by the amount of such deflection4 ,by using a reflecting galvanometer a very much more delicate test would be obtained1 but for the comparatively short lengths of electric cables used in connection with submarine mines1 such accuracy is hardly necessary4 ,to test an electric cable for conductivity1 it would be only necessary to expose the metallic conductor ,g1 and put it in the water of the tank4 ,if the conductivity were good1 then the whole of the current would pass through the cable and the needle of the galvanometer would be violently deflected4 ,if the continuity were broken1 no deflection would be observed4 ,defects observed in the ,conductivity of the ,cable4--,to ascertain the position of a defect in the insulation of a cable1 as indicated by the tests above described1 it would be only necessary to keep a continuous current flowing through the cable1 and gradually take it out of the tank4 ,if the fault existed at a single point1 the deflection of the needle would be suddenly reduced at the moment of that point of the cable being lifted out of the water1 and therefore its position would be determined with considerable accuracy4 ,should several defects exist as each was lifted out1 a sudden reduction of the deflection would occur4 ,discharge ,test4--,the conductor of an electrical cable may be broken without destroying the insulation1 and on applying the foregoing tests1 good insulation would be indicated1 but no conductivity1 and no information would be given as to the position of the fault4 ,under such circumstances the following test must be applied3-- ,put one pole of a very powerful battery to earth1 and charge one end of the defective cable1 then immediately discharge it through a reflecting galvanometer1 and note the extreme limit of the swing of the needle1 then1 charge the other end of the cable in a similar manner1 and discharge it through the same galvanometer1 noting as before the swing of the needle4 ,this should be done three or four times1 and the average of the deflections taken4 ,then the position of the fault would be indicated by the proportion between the average deflections in each case1 and the cable might safely be cut at that point4 ,should the precise position of the fault not be discovered in thus cutting the cable1 each section should be tested again for conductivity1 and that in which a fault was still found to exist should be again tested by the discharge as before4 ,test of ,electrical ,resistance of ,cable4--,this is effected by balancing it against the ,wheatstone balance1 in a similar manner to that explained for a fuze4 ,the electrical resistance of the conductor of a cable affords a very correct indication of the quality of the metal of which it is composed4 ,for a very delicate test the reflecting galvanometer should be used4 ,electrical ,test of ,insulated ,joints4--,insulated joints and connections1 whether of a permanent or temporary nature1 should be tested electrically1 in a precisely similar manner to that explained for electric cables4 ,they should be soaked for forty-eight hours1 and then tested for insulation1 conductivity1 and electrical resistance4 ,in testing permanent joints special tests are carried out1 which are described by ,mr4 ,culley in his ',handbook of ,practical ,telegraphy4' ,voltaic batteries should be subjected to the following tests3-- #a4--;,for potential4 #b4--;,for internal resistance4 #c4--;,for electromotive force4 ,for the purpose of testing the potential of a battery1 one pole should be put to earth1 and with the other one pair of the quadrants of a ,thomson's reflecting galvanometer should be charged2 when this is done1 a certain deflection of the spot of light will occur1 and the amount of such deflection1 as compared with that produced by a standard cell applied to the instrument in a similar manner1 would give the relative value of the potential of the battery4 ,the following method of determining the internal resistance of a battery is that recommended by ,mr4 ,latimer ,clark in his book on electrical measurements4 ,the instrument employed is a double shunt differential galvanometer1 a diagram of which is shown at ,fig4 #ig4 ,connect the battery and a set of resistance coils in circuit between the terminals ,a and ,d1 and insert plugs in the resistance coils so that they give no resistance2 insert plugs at ,a and ,c1 and also both the shunt plugs at ,a and ,d4 ,the current will now flow through one half of the galvanometer circuit only1 being1 however1 reduced to #a_/ajj of its amount by the shunt ,d2 the deflection of the needle must be carefully read4 ,the plug ,a must now be removed to ,b1 which causes the battery current to flow through both halves of the galvanometer 7each being shunted74 ,the circuit will now be as shown in the figure1 and the needle will of course be deflected somewhat more than before4 ,now unplug the resistance coils which are in circuit with the battery until the deflection of the needle is reduced to its original amount1 and the resistances unplugged will be equal to the internal resistance of the battery4 ,the following is another method of ascertaining the internal resistance of a battery cell4 ,a circuit is formed1 consisting of the battery cell1 a rheostat1 and a galvanometer1 and the strength ,c is noted on the galvanometer4 ,a second cell is then joined with the first1 so as to form one of double the size1 and therefore half the resistance1 and then by adding a length l of the rheostat1 the strength is brought to what it originally was1 ,c4 ,then if ,e is the electromotive force1 and ,r the resistance of cell1 r the resistance of the galvanometer1 and other parts of the circuit1 the strength ,c in the one case is ,c ,e _/ 7,r r71 and in the other ,e _/ 77#a_/b7,r r l71 and since the strength in both cases is the same1 ,r #bl1 i4e41 the internal resistance of the cell is equal to twice the resistance corresponding to the length l of the rheostat wire4 ,the comparative electromotive force of a battery may be determined by means of a double shunt differential galvanometer in the following method1 as recommended by ,mr4 ,latimer ,clark4 ,this can only be done relatively in terms of some other standard battery4 ,first determine the resistance of the standard and of the other cells to be measured2 then insert the shunt plugs at ,a and ,d1 ,fig4 #ig1 and also at ,c and ,b1 and join up the standard cell in circuit with a resistance coil to the terminals ,a and ,d1 and unplug the resistance coils until a convenient deflection is obtained1 say #ae2 note the sum of the resistances in circuit1 including that of the battery galvanometer1 resistance coil and connecting wires2 now change the battery for another1 and by unplugging the resistance coils bring the needle again to the same deflection1 #ae2 having again found the total resistance in the circuit1 the relative electromotive force will be directly proportional to these resistances4 ,the electromotive force of a battery may also be measured statically by means of ,thomson's quadrant electrometer1 the poles of the battery being connected with the two chief electrodes of the instrument1 in which arrangement no current will pass1 and the electromotive force will be directly indicated by the difference of potential observed4 ,in the case of a quantity battery1 that is1 a battery capable of fusing a fine platinum wire1 its electromotive force and internal resistance may be determined by means of the resistance coils ,k1 and thermo galvanometer ,m1 shown at ,fig4 #ie4 ,tests after ,submersion4--,after an electrical submarine mine has been placed in position1 it should be immediately tested to ascertain that all is right1 and similar tests should be applied at intervals to ascertain that the charge remains dry2 that the insulation and conductivity of the electric cable remains the same2 and that its electrical resistance indicates a state of efficiency4 ,the nature of the tests applied to determine these points will depend upon the nature of the combination in which the mine is arranged4 ,the manner of applying the sea cell test1 by which is ascertained the condition of a system of electrical submarine mines1 will be readily understood from the following examples4 ,the arrangements for testing to ascertain whether a charge is dry1 or wet1 is shown at ,fig4 #ih4 z is a plate of zinc introduced in the circuit within the charge1 and between the fuze and the shore2 another earth plate of carbon x is connected with the electric cable beyond the fuze1 forming the ordinary earth connection of the system at that point2 and at home a copper earth plate c is used4 ,first1 in the case of a dry charge with the insulation and conductivity of the cable1 good2 under these circumstances there would be formed a sea cell between the earth plates x1 and c1 which would produce a certain deflection of the needle of a galvanometer g1 which is placed in the circuit1 and in a certain direction4 ,secondly1 in the case of a charge becoming wet1 through leakage1 with the insulation and conductivity of the cable1 good2 under these circumstances1 a sea cell would be formed between the plates c and z1 causing a different deflection of the needle in amount and in direction1 by which it would be at once indicated that the charge had become wet4 ,illustration3 ,,test ,,table1 ,,differential ,,galvanometer4 ,,plate ,,xxvii ,sea cell ,test for ,insulation4--,again1 in the case of the insulation of the electric cable being damaged to such an extent as to expose the copper conductor4 ,under these circumstances there would be formed a sea cell between the copper earth plate c1 and the exposed copper conductor of the cable1 by which a certain definite deflection of the galvanometer would be observed1 which deflection would differ in character from that produced by the copper carbon sea cell1 when the insulation of the cable was good1 and the system in working order1 and therefore it would indicate that some change in the electrical conditions of the system had occurred4 ,the fact that a leak existed in the insulation would be proved by changing the earth plate at home from copper to zinc1 carbon1 tin1 c4 ,in the case of no deflection being produced on the galvanometer1 on applying the sea cell test1 a want of continuity1 or inefficient connections would be indicated4 ,the foregoing afford examples of the vast utility of the sea cell in connection with a system of electrical tests for submarine mines1 numerous variations of which may be effected by employing a series of earth plates1 of different metals1 at the home end of the circuit1 in connection with a carbon and zinc earth plate at the other end4 ,and the mode of manipulating these tests may1 by means of numerous switch plates1 as shown at ,fig4 #ie1 be made extremely simple and efficient4 ,armstrong's ,system of ,electrical ,testing4--,a very simple method of testing electrical submarine mines1 with which low tension fuzes are used1 has been devised by ,captain ,armstrong1 ,r4,e41 and is shown at ,fig4 #ii4 a is the electric cable leading from the shore2 b the cable attached to a polarised relay c1 and connecting the charge through the fuze f to the earth2 b' the cable1 attached to another polarised relay c'1 and connecting the mine with the circuit closer2 the polarised relay c1 in the mine1 is arranged to be worked by a positive current1 that is to say1 the wire surrounding the core is so wound as to increase the polarity of the electro magnet1 near the armature d1 when a positive current is passed through it1 and to diminish the polarity when a negative current is passed through the wire surrounding the core2 the polarised relay c' within the circuit closer is arranged to be worked by a negative current1 the coil being so wound as to produce an influence exactly the reverse of c4 ,then1 a positive current passing along the line wire a1 the armature d in the charge will be attracted1 while d' will remain unaffected2 again1 if a negative current be circulated1 the armature d' within the circuit closer will be attracted1 while the armature d will remain unaffected4 ,two insulated wires forked together are wound round each electro magnet1 one a thin wire 7g and g'7 having a considerable resistance1 about #ajjj ohms1 being connected direct to the earth plates e and e'1 and the other a thick wire 7h and h'7 offering a very small resistance1 and so arranged that when the armature is attracted1 they may be in contact with and complete the circuit through the armature to earth4 ,the thin wire coils are so arranged that a certain number of ,leclanch cells 7ten or twelve1 as may be desired7 will make the electro magnets act1 while with fewer cells the current would be too weak1 and would therefore pass through them to earth without affecting the armature4 ,by means of the three-coil galvanometer1 a table of the deflections1 obtained by the foregoing system of testing1 should be carefully recorded1 when the circuit is known to be in good working order1 so that any defect in the circuit would be at once indicated on the application of the various tests1 by the results so obtained differing from those originally recorded4 ,when a system of submarine mines is placed in position for the purposes of practice and experiment1 every trouble should be taken to endeavour to fix the exact position of any defect that may exist1 also to ascertain its magnitude1 c41 but in time of war1 should a defect exist in the system1 no time must be lost in such operations1 but the mine at once lifted1 and the fault repaired1 or a fresh one laid in its place1 unless the presence of an enemy or other imperative cause should prevent such work being done4 ,austrian ,testing ,table4--,the following is a description of the ,austrian testing table1 and their mode of making electrical tests with it1 in connection with their system of self-acting electrical submarine mines4 ,illustration3 ,,methods ,,of ,,testing4--,,armstrong1--,,austrian4 ,,plate ,,xxviii ,its design is shown at ,fig4 #ajj2 c z represents the battery with one pole to earth at e1 and the other in connection with an intensity coil a1 through which the current passes to the contact plate b4 ,when it is desired to put the system of mines in connection with the table1 in a state of preparation to be fired by the contact of a vessel1 a plug is inserted between the contact plates b and f1 and the current passes through the galvanometer g1 and electrically charges the conducting wires connecting the mines with the battery1 through the several binding screws on the contact plates1 numbering #a1 #b1 #c1 c4 ,the fact that the charge has been fired is also at once indicated on the galvanometer g4 ,test to discover an ,exploded ,charge4--,it then becomes necessary to ascertain which particular mine of the system has been exploded2 for this purpose a separate circuit in connection with a single cell d is employed4 ,this cell is in connection through a galvanometer g' 7a more sensitive instrument than the galvanometer g7 with the pivot of the key h1 and rheotome ,r1 which latter is connected1 as shown by the dotted lines1 with each individual mine of the system attached to the contact plates numbered #a1 #b1 #c1 c4 ,the handle of the rheotome is moved round1 to each number in succession and directly it is placed in contact with that corresponding to the exploding mine1 the electrical circuit is completed through the exposed end of the fractured wire1 and this is indicated by the galvanometer g'4 ,during the testing process the firing battery c z must be disconnected2 this is done by raising one of the bridges i i with which each group of ten mines is provided4 ,insulation ,test4--,the rheotome and testing galvanometer g' are also used to test the insulation of the electric cables connecting the mines to the testing table4 ,this is done in precisely the same manner as testing for an exploded mine3 the handle of the rheotome is turned round1 and each cable connected in succession with the testing circuit as before2 should the galvanometer g' remain stationary1 the insulation is good2 but should a defect of insulation exist1 the current passing through it would act on and deflect the galvanometer1 indicating the particular line in which it exists1 and1 roughly1 its extent in proportion to the deflection shown2 should the fault be considerable1 the defective cable should be at once detached1 as the current lost through it might so diminish the working power of the firing battery1 as to prevent it exploding any of the fuzes attached to the group in connection with it4 ,by the above arrangement1 the insulation of each line can be tested at any moment required4 ,in making the delicate test for insulation1 which should invariably be done at leisure1 and1 if possible1 when an enemy's vessels are not in the vicinity of the mines1 a large number of ,daniell's or other cells of suitable form should always be used4 ,to do this1 it would only be necessary to connect such a battery in place of a single cell permanently arranged1 as described1 in the testing circuit1 and to proceed with the details of the operation as before4 ,as the cable would1 in actual work1 always be charged with the full power of a firing battery1 the value of its insulation to resist an electrical charge at such a high potential would be an important point to determine4 ,the fuzes being entirely out of the circuit till the moment of the action arrives1 no danger of a premature explosion need be apprehended2 if a fuze were in such a position as to be fired prematurely1 it would be exploded1 in connection with the firing circuit1 independently of the operation of testing the insulation of the cables4 ,to render a ,channel ,safe4--,in order to render the channel safe for a friendly vessel1 it is only necessary to remove the plug from between the contact plates b and f2 this disconnects the firing battery from the circuit4 ,defence of ,harbours by ,booms1 c4--,booms or cables supported by rafts may also be employed in the defence of harbours1 or rivers1 either by themselves1 or in combination with submarine mines2 in the latter case1 the booms1 c41 may be moored either in advance of the mines1 or in rear of the front row1 this last method of mooring them being the most effective one4 ,there are a great variety of forms in which a boom may be constructed4 ,the qualities essential for a good and practicable boom are3-- #a4--;,great strength4 #b4--;,great power of resistance4 #c4--;,convenience in handling4 #d4--;,easy to manipulate4 #e4--;,its materials easily procurable4 ,construction of a ,boom4--,the general construction of a boom consists of a main cable1 buoyed up at intervals by floats4 ,the main cable may be either wire1 chain1 or rope1 the former being very much superior for this purpose to chain or rope4 ,the floats consist of balks of timber built round the main cable and bound together by means of iron hoops c4 ,a space is left between each float1 by which a certain amount of flexibility in the boom is obtained1 without which it would be of comparatively little use1 as it might be easily overrun4 ,it must be borne in mind1 in constructing all such booms1 that the smaller the proportion of timber used in forming the floats to the cable1 consistent with buoyancy1 the stronger will be the structure4 ,a very important feature in connection with such a mode of defence is the manner of mooring it2 for if it be moored so as to be unyielding1 then its sole power of resisting a vessel charging it is the actual strength of the materials composing the structure1 but if it be moored so that it is capable of yielding to a sudden blow1 this force will be to some extent absorbed1 and resistance of the defence greatly increased4 ,the raft employed to support the main cable should be moored by means of very heavy chains 7without anchors7 in the direction of the attack1 and with ordinary anchors and cables on the other side4 ,as a rule1 the booms should be moored obliquely to the direction of the current1 where there is any1 as the tendency of the current to overrun the boom when so placed will be less1 and also a ship ramming it must place herself athwart the current to attack the boom at right angles4 ,clearing a ,passage through the ,torpedo ,defences of an ,enemy4--,the subject of clearing a passage through the torpedo defences of an enemy is one fraught with innumerable difficulties1 on account of the varied nature and impracticability of obtaining accurate and certain information of such defences1 and thus it is impossible to lay down any fixed rule or plan for carrying out such an operation4 ,in fact1 it will be only under the most favourable circumstances that such a service will be successfully accomplished1 that is to say1 in the case of a harbour or river defended by submarine mines but unsupported by guns1 or guard boats1 or where the electric light is used4 ,numerous methods have been devised from time to time to effect the destruction of an enemy's submarine defences1 among which are the following3-- #a4--,projecting frames1 c41 from the bows of a vessel4 #b4--;,creeping and sweeping by boats4 #c4--;,countermining4 ,projecting ,frames1 c41 from the ,bows of a ,vessel4--,this method was adopted by the ,federals during the ,american civil war of #ahfa-e1 and in many instances it was the means of saving their ships when proceeding up rivers which had been torpedoed by the ,confederates1 though notwithstanding this precaution several vessels were sunk4 ,the submarine mines against which this mode of defence was used1 were in nine cases out of ten mechanical ones1 and therefore the framework defence afforded a better means of protection then1 than would be the case now that electrical ground mines and circuit closers are used1 as the framework would catch the circuit closer only1 and the vessel would probably be over the mine when the explosion took place4 ,the ,americans moor their circuit closers in rear of their mines1 so that a vessel fitted with a bow frame or not1 coming in contact with the former must be right over the charge at the instant of explosion4 ,against ground electrical mines fired at will1 the bow net1 c41 is no protection whatever1 still under certain circumstances it would be found extremely useful4 ,sweeping for ,submarine ,mines4--,this method of clearing a channel of submarine mines could not possibly be carried out under artillery fire1 but in waters not so defended it would prove of some value4 ,where only buoyant mines1 or ground mines with circuit closers are to be cleared away1 two or more boats dragging a hawser between them would be sufficient to discover them1 and so lead to their destruction2 but where dummy mines and inverted creepers are moored in addition1 another method of sweeping must be resorted to1 viz41 that of bringing an explosive charge of gun-cotton to act on the obstruction grappled1 and thus destroy it4 ,this is effected by lashing a charge to each end of the sweep1 so that whatever is grappled may slide along it1 until caught by hooks1 which are attached for this purpose to the centre of the charge4 ,on grappling an obstruction1 the two boats drop their anchors1 one hauling in1 the other veering out the sweep1 until the charge is hooked by the obstruction2 this being effected1 the boats move out of range1 and the charge is fired4 ,creeping for ,electrical ,cables1 c4--,creeping is the method employed for picking up the electric cables of the enemy's submarine mines1 and is effected by boats towing an ordinary grappling iron1 or specially prepared creeper on the ground4 ,in both sweeping and creeping it would be found necessary to employ a diver1 who would ascertain the nature of the grappled obstructions which could not be easily raised by the boats4 ,the ,lay torpedo boat1 which is fully described in the chapter on offensive torpedoes1 is capable of being used for the foregoing purposes4 ,countermining4--,countermining1 that is1 the destruction of submarine mines by the explosion of other mines dropped close to them1 will under certain conditions prove of great use in clearing harbours of mines4 ,this method could not be operated in waters properly guarded and swept by artillery fire4 ,there are two distinct methods of laying out countermines1 viz43-- #a4--;,in a boat1 which may be either towed1 or hauled out to its destination1 or may be steered1 and controlled by electricity4 #b4--;,by attaching them to buoys so that they are suspended at the proper depths1 and then hauled out by means of a warp to an anchor which has been previously placed in position4 ,both of the foregoing methods have been successfully manipulated in practice1 the first method1 where the boat carrying the countermines is towed either by a pulling or steam boat being the most practicable one4 ,a large amount of material would be required for clearing a channel by means of countermines3 for example1 if the mines to be attacked require #ejj-lb4 gun-cotton charges to be used1 #g-a_/b tons of the explosive1 besides cables1 buoys1 c41 would be required to clear a passage about one mile in length and #bjj feet in width4 ,a ship's launch will carry about twelve of these #ejj-lb4 countermines1 with all the gear attached thereto4 ,experiments to ascertain the effect of countermining have been carried out in ,england and ,europe for the last five years1 some of which are given at length in the chapter on ,torpedo ,experiments4 ,during the ,turco-,russian war1 a portion of the ,danube was swept in the ordinary and most simple manner by the ,turks1 and five ,russian electro contact buoyant mines were picked up2 one other exploded during the process of dragging it to the surface1 but no injury occurred to those at work4 ,destruction of ,passive ,obstructions4--,to clear away booms1 or other passive obstructions1 if not possible to cut them away1 they may be destroyed by outrigger boats exploding their torpedoes underneath1 and in contact1 or by attaching charges of gun-cotton at intervals1 and then exploding them simultaneously4 ,when a chain is horizontal1 and therefore somewhat taut1 a charge of #c-a_/b lbs4 of gun-cotton 7this explosive1 being the most effective and convenient for such purposes1 should always be used7 will be found sufficient to destroy it1 no matter what size1 and whether the chain is in or out of the water1 the charge being of course placed in contact with it4 ,great uncertainty must always attend the supposed clearance of a channel1 or passage of submarine mines1 as was exemplified during the ,american civil war1 when most of the ,northerners' vessels were destroyed while moving over ground which had been previously carefully dragged1 and buoyed1 and this fact1 coupled with the tediousness and danger of performing such a service1 proves the enormous value of a system of defence by submarine mines4 ,,footnotes3 ,footnote ,j3 ',electricity and ,magnetism1' by ,professor ,f4 ,jenkins4 ,footnote ,k3 ,see ,appendix4 ,footnote ,l3 ,as constructed by ,mr4 ,j4 ,mathieson1 late ,r4,e41 at the ,silvertown ,telegraph ,works1 ,essex4 ,,chapter ,v4 ,,offensive ,,torpedo ,,warfare4 ,,the term ,torpedo is applicable more particularly to offensive submarine mines than to those employed for the purposes of defence1 and therefore by torpedoes will be understood every kind of submarine explosive weapon designed to be used for active attack against vessels1 c41 no matter how they may be manipulated4 ,offensive ,torpedo ,warfare still in its ,infancy4--,though during the seventeen or eighteen years that torpedoes have been considered as a legitimate mode of naval warfare there have occurred three big wars1 in each of which submarine weapons1 offensive and defensive1 have played an important part1 still the subject of offensive torpedo warfare must be even now considered as in its infancy1 and therefore any opinions expressed as to the merits and demerits of the various apparatus in connection therewith can but be based on the theoretical capabilities of each torpedo1 and on the results of experiments carried out with them during peace time1 which latter as a rule are conducted under far too favourable conditions to be relied upon4 ,their ,use during the ,civil ,war in ,america4--,during the ,american civil war1 the only offensive submarine weapon that was used was the outrigger or spar torpedo1 which in those days was a crude and imperfect machine1 and manoeuvred from boats possessing all the features which a torpedo boat should not possess4 ,still under these unfavourable conditions ships were sunk by such means by both ,federals and ,confederates1 proving that in future wars this mode of attack1 favoured by the vast and important improvements that have lately been effected both in connection with the torpedoes and torpedo boats1 should play a prominent part1 and prove a most destructive mode of attack4 ,their ,use in the ,franco-,german and ,russo-,turkish ,wars4--,in the ,franco-,german war of #ahgj-a1 offensive torpedo warfare was not resorted to by either side1 the ,french fleet being deterred from entering ,german waters by the submarine mines placed1 or at least supposed to be placed1 in position4 ,from the ,russo-,turkish war much light was expected by torpedoists to be thrown on the subject of torpedo warfare1 but alas1 little or nothing was done to settle any of the many vexed questions which exist in regard to offensive submarine weapons4 ,the torpedo experience of that struggle tended rather to prove that the vast importance hitherto attached to torpedo attack was much exaggerated4 ,one of the causes which led to the failure of offensive submarine weapons1 when employed on active service1 seems to be due to the fact that1 owing to the extremely small radius of the destructive effect of such weapons1 it is absolutely necessary for complete success to explode the mine in actual contact with the attacked vessel2 to ensure which1 at night time1 in an unknown harbour1 with the position of the vessel attacked somewhat uncertain1 and even without the additional obstacles of guard boats1 booms1 electric lights1 c41 is a service of infinite difficulty1 and one which may easily terminate in a failure4 ,the foregoing would more especially apply to the spar torpedo attack1 but in an attack with the ,whitehead fish1 or towing torpedo1 there would be an additional cause of failure1 viz41 the complicated nature of their manipulation4 ,torpedoes may be divided into four classes1 viz43-- #a4--;,drifting or floating torpedoes4 #b4--,towing torpedoes4 #c4--,locomotive torpedoes4 #d4--,outrigger or spar torpedoes4 ,drifting or ,floating ,torpedoes4--,by drifting or floating torpedoes are meant all those submarine machines which are dependent on the tide or current of a stream for their action and motion4 ,during the ,american civil war this mode of attacking vessels was constantly employed by the ,confederates1 and though not successful in destroying any of the ,federal ships1 was the means of considerably hampering the movements of their river flotillas4 ,drifting torpedoes might be advantageously used for the destruction of pontoon bridges1 booms1 c41 and in this way1 had the ,turks in their late war used them1 the ,russians would have found the crossing of the ,danube a matter of infinite danger and difficulty2 in fact1 by a systematic use of such weapons1 combined with a little dash on the part of the ,ottoman flotilla on the ,danube1 that river should have been to the ,russians an impassable barrier4 ,to use these torpedoes most effectively1 especially against a single vessel1 a thorough knowledge of the force and direction of currents should be gained before proceeding to undertake an operation in which these submarine weapons are used4 ,another point to be remembered is1 that if such a torpedo were started with the flood1 for example1 towards an enemy1 and did not explode1 there would be a chance of its being returned to the starting-place by the ebb tide4 ,in this class the following torpedoes seem the most practicable3-- #a4--,lewis's drifting torpedo4 #b4--,mc,evoy's drifting torpedo4 #c4--;,american extempore drifting torpedo4 ,description of ,lewis's ,drifting ,torpedo4--,lewis's drifting torpedo1 designed for the express purpose of destroying booms or other floating obstructions placed round a vessel at anchor for the purposes of defence1 is shown at ,fig4 #aja4 ,it consists of a box a1 containing the charge and fitted with several detonating fuzes4 ,this box is attached to one side of a beam b1 and within #f inches of one extremity1 the beam being about #bj feet long and #g inches square2 to the opposite side1 of the same end of the beam b a heavy weight c1 resting in a shoe d1 is attached by a long iron rod e1 which reaches to the other extremity of the beam1 and is there connected to a bell-crank lever and spring f1 a pressure on which detaches the weight c2 a chain g1 #ah feet long1 connects the weight loosely with the upper end of the beam1 and another chain h1 #i feet #f inches long1 connects it with a point more than #b feet below the centre of the beam4 ,the apparatus is so constructed that it floats nearly vertical with the top of the beam just above the surface of the water4 ,on the machine drifting against the boom or other obstruction1 the spring or lever f at the upper extremity is pressed down1 thus releasing the weight c1 which falling1 becomes suspended by the two chains g and h1 and brings the beam into an inclined position4 ,the weight of this mass of iron and the chain suspending it are suddenly brought to bear on the top of the beam1 dragging it under water and clear of the boom1 c4 ,at the same time the lower end1 released from the weight1 rises1 and the whole apparatus is carried forward by the current against the side of the vessel1 on striking which the torpedo is exploded4 ,description of ,mc,evoy's ,drifting ,torpedo4--,mc,evoy's drifting torpedo is intended to be floated1 singly or in groups1 by the aid of tides or currents against vessels at anchor1 bridges1 c4 ,at ,fig4 #ajb is shown a plan of this form of drifting torpedo4 ,it consists of the body of the torpedo a1 which contains the charge1 at the side of which is placed the loading hole b2 c is the tube containing the priming charge2 d is the framework surrounding and protecting the wheel or screw e2 f is the fuze pillar1 in the centre of which is a steel rod g1 and on the top a thin steel plate h is placed2 i is the nipple for the percussion cap2 k is a horizontal bar1 turning and resting on top of the fuze pillar f2 m is the lever for supporting the hammer n when it is set2 l is the screw barrel supporting the wheel or screw e2 o is a safety pin2 q is the supporting chain1 and p the spring for working the hammer n4 ,by means of a buoy or log of wood1 from which the torpedo is suspended1 it can be adjusted so that the explosion shall occur at the requisite depth4 ,to prepare the torpedo for use1 unscrew the fuze pillar f1 take off the horizontal bar k1 place a percussion cup on the nipple i1 and screw it tightly against the end of the steel rod g4 ,the fuze pillar is then ready for use1 and should be screwed into the body a4 ,then fill the torpedo with the explosive and close the loading hole b4 ,the hammer n is then set by drawing it back and bringing the end of the lever m against it1 at the same time running the screw barrel l under the lever m1 so that its end catches the screw of the barrel1 as shown in the figure4 ,the safety pin o is then put in its place and secured by a few parts of thread1 which by a sharp jerk on the safety line will be easily broken4 ,illustration3 ,,drifting ,,torpedoes4 ,,plate ,,xxix ,the horizontal lever k1 which carries the lever m and propeller e1 rotates on the top of the fuze pillar f1 and is prevented from rising by means of a screw4 ,the torpedo being let go1 the safety pin o is pulled out by means of a line which is attached to it4 ,the propeller will not revolve whilst the torpedo is drifting with the current1 but the instant it is stopped by the action of the current the wheel will be caused to revolve1 and after a few revolutions it will unscrew the barrel from under the end of the lever k1 and the latter1 dropping the hammer n1 will be forced by the spring p into contact with the thin steel plate h on the top of the fuze pillar1 which blow is transmitted by means of the steel rod g to the percussion cap1 and the torpedo exploded4 ,american ,extempore ,drifting ,torpedo4--,this form of drifting torpedo1 which is readily made1 was used in great numbers by the ,confederates1 and though not successful in sinking any ,federal ships1 caused their vessels considerable annoyance and delay4 ,at ,fig4 #ajc is shown a sketch of this torpedo4 ,it consists of a tin case containing about #gj lbs4 of powder4 ,a stiff wire a1 b passes through a hole punctured in a strip of tin c1 and a stuffing box d2 the end a of the wire is covered with fulminate1 and so arranged that the friction caused by its passage through the strip of tin c will ignite it2 a number of wires lead from b to pieces of driftwood on the surface e1 e1 e1 and the case is supported at the proper depth by a line attached to a section of log4 ,towing ,torpedoes4--,by towing torpedoes are meant those submarine machines which are so shaped and arranged1 that when towed from a ship or boat in motion they will diverge to a considerable extent1 thus enabling the towing vessel to pass clear of the ship attacked1 and yet near enough to allow of the torpedo being brought in contact with some part or other of her hull4 ,towing torpedoes were for the first time employed on actual service during the late ,russo-,turkish war1 when a modified form of the well-known ,harvey torpedo1 designed by a ,german officer1 was used by the ,russians1 but in no case was it successful4 ,in this class of submarine offensive machines may be placed the following3-- #a4--;,harvey's towing torpedo4 #b4--,menzing's towing torpedo4 #c4--,the ,french towing torpedo4 ,harvey's ,torpedo4--,this form of towing torpedo was invented conjointly by ,captain ,john ,harvey and ,commander ,frederick ,harvey1 ,r4,n41 and is intended to be used at sea both as a means of offence and defence4 ,at ,fig4 #ajd is shown in elevation the small sized ,harvey towing torpedo1 in which all the latest improvements that have been devised are represented4 a is the case of the torpedo1 formed of ,muntz's metal1 but not provided1 as the original ones were1 with an exterior case of wood2 by this alteration greater capacity combined with extreme lightness is obtained1 which undoubtedly much enhances the value of the small size torpedo which is intended to be carried by and manoeuvred from boats2 b is the principal or after lever1 hinged on the top of torpedo at c1 and rests1 when ready for action1 in a crutch formed in the top of the exploding bolt d2 e is the foremost lever1 hinged at f1 and kept in position on the after lever b by a groove formed in it and a lashing which passes through a slot in the principal lever1 as at g2 h is the side lever1 pivoted at i1 and exerting a pressure on the firing bolt d by means of a lanyard which is passed through the bolt k and over the principal lever b2 l is the top lever1 pivoted at m1 and exerting a pressure on the bolt d by means of a lanyard which is passed through the bolt n and over the principal lever b2 this top lever l has been added to ensure the action of the torpedo1 on its striking sideways against a vessel2 o and t are handles1 to the former of which the lashings of the levers h and l are secured2 p is the ring used for attaching the buoy rope2 r1 r are two loading holes1 made in the side of the torpedo case1 by which a charge of gun-cotton may be quickly and efficiently stowed2 this also is a new feature in the small size torpedo2 s is the rudder formed for the purpose of controlling the direction of the torpedo when the tow line is suddenly slacked4 ,in regard to the large size torpedo1 the construction of the case remains as in the original ones1 the improvements being1 the enlargement of the loading and fuze holes1 and the addition of the top lever l1 as shown at ,fig4 #ajd4 ,the small size torpedo is capable of holding #dg lbs4 of water1 whilst the large size one will contain #gf lbs4 of water1 or about #cc lbs4 and #eh lbs4 of gun-cotton respectively4 ,the slings are made of best ,italian hemp1 and consist of a span of four legs1 which are secured to lugs at the corners of the torpedo and connected to an iron thimble1 which is shown at ,fig4 #aje2 this thimble is made suitable for either wire or hemp rope1 and is so arranged that should the seizing become slack1 the parts of the slings cannot become detached from the thimble4 ,illustration3 ,,harvey',s ,,towing ,,torpedo4 ,,plate ,,xxx ,the legs of the slings should be so fitted that when stretched alongside the torpedo they extend #a foot beyond the stem for the large torpedo and #h inches for the small one2 the four legs should be so fitted that when an equal strain is brought on them1 the thimble should be on a level with the upper lugs1 and the upper fore span form an angle of #hj to #he with the side of the torpedo2 this is shown at ,fig4 #ajf4 ,this arrangement gives the best divergence with the least strain on the tow rope1 and is suitable when the torpedo is kept at short scope1 as well as when a long length of tow line is out4 ,the mode of attaching the foremost and side levers is shown at ,fig4 #ajg4 ,before reeving the lanyards they should be well greased in the wake of the fair leads1 but not where they are made fast4 ,the lanyards should be made up like a reef point4 ,care should be taken that the short arm of the side lever h is brought close into the fair lead1 and its lanyard should be set up sufficiently taut to give a slight spring in the principal lever b by the strain thus brought on it4 ,this lever b has a steel fish on the top1 in order to prevent it taking a permanent bend4 ,if the side lever lanyard is properly set up1 the bolt will spring down about #a_/hth of an inch when the safety key is withdrawn1 owing to the spring in the lever1 and the shrinking of the lanyard2 this brings the muzzle #a_/hth of an inch nearer the pin without disturbing the side lever4 ,the bolt is so arranged that the torpedo can be fired by either of the following methods3-- #a4--,mechanically4 #b4--;,electrically at will4 #c4--;,electrically on contact or at will4 ,mechanically4--,in this case the bottom of the inner cylinder1 as at a1 ,fig4 #ajh1 is fitted with the ordinary mechanical chemical fuze1 ignition being effected by the breaking of the glass vessel containing the sulphuric acid on being forced into contact with the needle n1 by the action of the levers on the torpedo striking a vessel4 ,electrically at ,will4--,for this purpose a platinum wire fuze is used1 one terminal being connected to earth through the bolt1 the other to a wire leading up through the core of the bolt1 and connected by means of an ebonite joint with a single cored electrical cable leading from the torpedo vessel4 ,electrically on ,contact1 or at ,will4--,in this case1 a resistance coil is inserted in addition to the fuze1 and is so arranged that on the bolt being forced down a short circuit is formed1 cutting out the resistance coil 7about #bj ohms71 and thus enabling the battery to fire the fuze1 which1 owing to the #bj ohms resistance in the circuit1 it was previously unable to effect4 ,should the bolt so arranged be required to be fired at will1 it is only necessary to put a more powerful battery in circuit1 and so fire the fuze through the #bj ohms resistance4 ,exploding ,bolt4--,the exploding bolt is fitted to act with a pressure of from #cj to #dj lbs4 on its head for the large size torpedo1 and from #ae to #bj lbs4 for the small size one4 ,the bolts are all the same size1 and differ only in the direction of the slot for the safety key k1 being port or starboard bolts accordingly4 ,the muzzle of the exploding bolt stands #a inch off the pin when in the safety position1 that is1 when the safety key rests on the brass work of the priming case4 ,the safety key is secured in the slot of the exploding bolt1 as shown at ,fig4 #ajh1 by eight or nine parts of strong whitey-brown thread secured to the key1 passed round the bolt1 and securely knotted2 the parts of the thread should come away with the key1 in order that none of the parts may be worked down the tube by the exploding bolt4 ,in the event of the large torpedo being cut away in deep water after the withdrawal of the safety key1 it will explode by pressure on the head of the bolt at about sixty fathoms depth2 the small one at about thirty fathoms4 ,buoys4--,the buoys are of two sizes1 and are made of solid cork 7such cork only being used as will ensure great floating power after being immersed for a time72 each buoy is built upon a galvanised iron tube running longitudinally through2 on the ends of the tube are screwed wooden cones1 which bind all together1 and render the buoy indestructible4 ,two buoys are used for each torpedo1 the larger buoys for the large size torpedo1 and the smaller buoys for the small size torpedo4 ,the buoy rope is of hemp1 about five or six fathoms in length and two inches in circumference1 an eye being spliced in the end nearest the torpedo2 to this eye is bent the tow rope1 with a single or double sheet bend forming the knot by which the torpedo is towed2 the other end of the buoy rope is passed through one of the rings in the stern end of the torpedo 7according to whether working in deep or shallow water71 then through the tube of the first buoy1 and an overhand knot made in the rear2 then through the next buoy1 and a knot in the rear of that4 ,recently1 ,captain ,harvey has adopted a large and a small buoy for each torpedo1 the large one being practically sufficient1 the smaller one being added in the event of the other one becoming sodden4 ,brakes4--,the brakes are used for the purpose of controlling the tow ropes2 they can be fixed by screws into the deck at the most convenient place for command1 and in a properly constructed torpedo vessel would be placed below the water line1 to prevent exposure of the men working them4 ,they are so arranged as to admit of the tow rope being quickly veered1 and at the same time are sufficiently powerful to bring the torpedo to the surface when required4 ,success greatly depends on the skilful handling of these brakes1 for in conjunction with the cork buoys they give the operator command of the depth at which the enemy is to be struck4 ,unless a very high rate of speed is required1 one handspike will control the tow rope2 the other strap can be thrown off the drum1 and the handspike allowed to lie on the deck ready to be thrown into gear1 if necessary4 ,the surface of the drum in contact with the strap should be powdered with rosin to increase the friction4 ,the tow rope should be so reeled up that in veering the reel may revolve towards the men at the handspike4 ,the spindle will contain several tow ropes1 that1 in the event of one torpedo being cut away1 another can be immediately bent4 ,the brake for small torpedo requires only one drum and handspike4 ,it can be fitted to a steam launch by placing an extra thwart across near one of the others4 ,care should be taken that the riding turns lie fairly over each other1 to prevent a jamb when veering4 ,the brakes1 both large and small1 are so made as to ensure durability1 they being considered a part of the ship's furniture4 ,brake for safety key line is a small reel on the same principle4 ,when going a slow speed1 it may not be necessary1 as the safety key line can be attended by hand2 but when going ten or eleven knots1 it will be found of considerable advantage1 both in keeping the bight of the safety key line from dragging astern1 thereby lessening the divergence of the torpedo1 and also in drawing the safety key when a strong stop is used4 ,arrangements for ,launching and ,towing the ,torpedoes4--,a yard across either the main or mizen mast of a torpedo vessel1 from #bj to #be feet above the water line1 is a very convenient method for launching and towing4 ,the leading block on the yard1 through which the tow rope is rove1 may be fitted to a traveller on the yard with an inhaul and outhaul1 that the distance out from the ship's side may be regulated as convenient4 ,in a large vessel1 the leading block for tow rope can be fixed to the end of the quarter-boat's davits4 ,the brakes for commanding the tow rope should be screwed firmly to the deck4 ,in a vessel properly constructed for the service1 they would be on the lower deck1 the tow rope having been led along the yard1 and down each side of the mast4 ,a leading block for the tow rope is placed on the deck by span or bolt a few feet in front of the brake4 ,the safety key reel1 if used1 must be fixed in a convenient position on deck1 that the man attending it can see how to control it2 in a properly constructed vessel he would be in the pilot house4 ,the safety key line leads through a small leading block on the ensign staff or some convenient point abaft the lead of the tow rope1 #ae to #bj feet above the water4 ,the leading block on the yard may be fitted with a lizard1 if thought necessary4 ,a sharp instrument should be kept by the brakes ready to sever the tow rope4 ,in large men of war1 arrangements are made for carrying a loaded torpedo and two buoys in a convenient position on each side of the vessel1 in such a manner that the tow line can be bent1 the exploding bolt screwed in1 the levers adjusted1 and the torpedoes and buoys dropped simultaneously when required4 ,preparing the ,torpedoes for ,use4--,the torpedoes1 port and starboard1 loaded and ballasted1 having been hoisted out of the torpedo room1 are placed on the deck on their own sides1 with their heads forward under the leading block1 and the buoys placed abaft them and strung together2 the exploding bolts are now entered into the torpedoes1 and forced down until their safety keys rest on the brass work1 taking care that each safety key points in the direction of the eye through which its lanyard has to pass2 the levers are now secured by their lanyards1 as explained at pages #abj and #aba4 ,the eye at the end of the buoy rope is now rove through the large or small ring in the stern end of the torpedo4 ,the tow rope having been previously rove through the leading block on the deck and on the yard1 is rove through the thimble of the slings from forward aft1 and bent1 with a single or double sheet bend1 to the eye of the buoy rope4 ,the safety key line having been previously rove through the leading block on the ensign staff1 and the lanyard on the safety key having been led through the eye of the handle1 making a fair lead with the slit in the bolt1 are bent together with a double sheet bend1 and stopped to the eye of the handle by a split yarn of suitable strength1 the yarn having been first secured to the line by a round turn outside the bend4 ,the line should also be stopped with another split yarn round all parts of the slings close up to the thimble1 having first made an overhand knot in the line at a distance a few inches longer than that between the eye bolt and the thimble4 ,the crew having been stationed at their respective posts1 the handles having been shipped on the tow reel1 the tow line is then reeled up until the torpedo will launch clear1 and swing out under the leading block on the yard4 ,hold the torpedo by the handspikes1 and take off the handles of the brake4 ,in swinging out1 care should be taken that in starting from the deck the fore slings do not foul the fore top lever4 ,the stern of the torpedo can be steadied by keeping a slight strain on the buoy rope4 ,the safety key line must be kept clear1 and not checked1 or it might break the stop and draw out the key before intended4 ,the buoys must be placed in a proper position and hands stationed by them to launch them overboard the instant the torpedo takes the water4 ,it would be better to stop the screw1 if circumstances would allow of it1 when lowering the torpedo and buoys into the water1 to prevent the chance of the buoys fouling the screw4 ,the torpedo1 on reaching the water1 will immediately diverge clear of the ship2 the buoys being launched1 as the strain comes on the buoy rope1 they will be towed clear away from the screw1 and full speed may be put on at once4 ,the men at the handspikes must veer steadily1 occasionally checking the torpedo1 that it may be kept near the surface1 and not allowed to dive1 which it will do if the tow rope is slacked up altogether1 and then a sudden strain brought on it4 ,eventually it will come to the surface1 when the bow is pointed up by the strain on the tow rope2 greater the speed the more quickly will it be brought to the surface4 ,in shallow water this should be particularly attended to1 as in diving it might strike the bottom and injure the levers1 and1 if the safety key has been withdrawn1 explode2 moreover1 it brings an undue strain on the tow rope4 ,the torpedo can now be gradually veered out to the distance required1 the safety key line so attended that a sufficient strain is kept on it as not to allow of a long bight of line dragging astern of the torpedo2 at the same time having due regard to the strength of the yarn by which the line is stopped to the handle of the torpedo4 ,the distance veered must depend upon the nature of attack4 ,the tow line should be marked with knots every #aj fathoms3 under some circumstances the torpedo would be close to the ship until passing the enemy2 at other times veered to #dj fathoms it will be found most suitable4 ,the full divergence of #de is obtained up to #ej fathoms2 beyond that the bight of the tow rope in the water drags the torpedo astern1 unless the tow rope is triced much higher up1 which has its disadvantage2 #dj to #ej fathoms of tow rope gives the best command of the torpedo1 veering #b or #c fathoms of tow line suddenly will always sink the torpedo some feet below the surface4 ,should it become necessary to use the torpedoes with a stern board1 they can be so used1 but in this case the port torpedo is used on the starboard1 bow and starboard on the port2 all other arrangements being exactly the same4 ,in rough weather1 advantage should be taken of the roll1 and the torpedo allowed to swing out from the yard1 and be let go by the run1 checking the tow rope immediately the torpedo is in the water4 ,it is not absolutely necessary to ease the vessel when launching2 the torpedo can be launched at full speed4 ,in the event of its being found necessary to cut adrift the torpedo1 in consequence of coming suddenly across a friendly vessel1 the tow rope should be cut near the brake1 and if the buoy rope has been rove through the large stern ring1 the torpedo will sink and be lost1 the buoy only remaining4 ,if the buoy rope has been rove through the small stern ring1 the torpedo will be suspended by the buoy rope2 and should the safety key not have been withdrawn1 can be recovered with safety4 ,in the event of wishing to recover it when the buoy rope has been rove through the large ring1 a toggle must be lashed on the tow rope abaft the leading block on the yard1 when it can be recovered by the buoy rope2 as a general rule1 however1 it will be found best to expend the torpedo1 and not attempt its recovery4 ,illustration3 ,,harvey',s ,,towing ,,torpedo4 ,,plate ,,xxxi ,illustration3 ,,systems ,,of ,,attack ,,with ,,harvey',s ,,towing ,,torpedo4 ,,plate ,,xxxii ,recovering the ,torpedo4--,should the safety key have been withdrawn1 great caution is necessary4 ,tongs1 shown at ,fig4 #aji1 for going round the upper part of the bolt1 to take the place of the safety key1 when once clasped and secured round the bolt1 render the torpedo safe to handle2 this could only be done from a boat4 ,with the safety key in1 there is no danger in hoisting it inboard again by its own tow rope1 and hoisting up the buoys at the same time with a grapnel4 ,different ,methods of ,using the ,torpedo4--,there are two methods of employing the torpedo1 either of which may be adopted1 according to circumstances4 #a4--,when it is towed with a length of line varying from #be to #fj fathoms1 and dipped when in position to strike the attacked vessel4 #b4--,when it is kept suspended from the yard1 c41 and dropped at the spot1 where according to the first method it would have been dipped4 ,in the first method1 it is not necessary to withdraw the safety key till just before dipping2 in the second method the safety key line is belayed at about twenty fathoms1 and the key withdrawn when the line is tautened by the ship going ahead4 ,tactics4--,description of the various attacks that may be made with the ,harvey torpedo against a ship at anchor or under way4 ,in the following diagrams ,t is the torpedo vessel1 ,s the ship attacked4 ,illustration 444444 ,the track4 ------ ,the tow rope4 ,o-o-o ,the torpedo4 ,attacking a ,vessel moored ,head and ,stern4--,in this case the torpedo vessel steers in for the bow or quarter of the vessel attacked1 according to the direction of the current1 and on the side approached launches the torpedo between the moorings1 as at ,a2 leaving the tow rope slack1 the torpedo vessel proceeds ahead or astern against the current1 and when at a sufficient distance off1 the tow rope is held fast1 which will cause the torpedo to diverge into contact with the vessel attacked1 as shown by ,fig4 #aaj4 ,attacking a ,vessel at ,anchor by ,crossing her ,bow4--,in this case the torpedo is sufficiently diverged when near to the vessel with a good scope of tow rope out4 ,after having crossed her bow1 proceeding onwards1 the tow rope will be brought obliquely across her cable1 and the torpedo will swing into her1 as shown at ,fig4 #aaa4 ,it may be here remarked1 that in all cases the depth of the explosion can be obtained by the sudden slacking of the tow rope2 and the tow rope once under the keel1 causes the torpedo to be hauled down near to it before exploding4 ,attacking a ,vessel at ,anchor by coming up from ,astern on either ,side4--,in this case the torpedo is launched when on the quarter of the vessel attacked1 as at ,a1 the tow rope left slack4 ,after steaming ahead some distance1 hold fast the tow rope1 when1 by continuing to steam on1 the torpedo will diverge into contact with the bottom of the vessel attacked1 as shown at ,fig4 #aab4 ,when skilfully performed1 the total destruction of the enemy is certain1 since the torpedo is springing from a depth to the surface1 and will1 in consequence1 strike near her keel4 ,the torpedo vessel can pass at her greatest speed1 and1 if thought necessary1 near enough to clear away any of the ordinary obstructions1 such as booms1 nets1 c4 ,passing ,down between ,two ,lines of ,vessels at ,anchor4--,in this case it would be impossible to fire at the torpedo vessel1 for fear of injury to their friends4 ,two or more torpedo vessels following each other with preconcerted signals would cause great destruction4 ,see ,fig4 #aac4 ,attacking a ,vessel in ,motion from ,right ,ahead4--,in this case two torpedoes are launched1 port and starboard1 each diverging to its full extent2 when passing the vessel attacked1 one or the other of the tow ropes is brought across the cut-water1 and by the simultaneous motion of the two vessels in opposite directions1 the torpedo is brought alongside of or under the bottom of the vessel attacked1 as shown at ,fig4 #aad4 ,the torpedo vessel should keep the masts of her enemy in one until close to1 when either torpedo will be used1 according to the movement of the enemy4 ,at the time of the tow rope taking the cut-water1 the brake is suddenly eased up2 the tow rope will then pass under the bottom1 when by checking the tow rope the torpedo will be hauled under the bottom4 ,to execute this attack1 judgment1 skill1 and nerve of the highest order will be required1 as the risk of being run down will be imminent4 ,the ,attack from ,astern4--,in this case two torpedoes are launched1 and diverged as in the previous case2 it is assumed in this instance that the torpedo vessel can outspeed the vessel attacked1 which will enable her to bring a torpedo under the run of the attacked vessel1 as shown at ,fig4 #aae4 ,illustration3 ,,systems ,,of ,,attack ,,with ,,harvey',s ,,towing ,,torpedo4 ,,plate ,,xxxiii ,illustration3 ,,systems ,,of ,,attack ,,with ,,harvey',s ,,towing ,,torpedo4 ,,plate ,,xxxiv ,if ,chased by a ,hostile ,vessel1 and unable to ,face her4--,in this case veer a torpedo astern1 having first obtained a position a little on the bow of the chasing vessel4 ,when it is known by the length of the tow rope out that the torpedo is about abreast of her bow1 hold fast the tow rope1 which will cause the torpedo to diverge1 and be brought into contact1 as shown at ,fig4 #aaf4 ,as a last resort drop spanned torpedoes4 ,torpedoes can be used with a stern board1 if necessary4 ,the port torpedo1 in this case1 will be launched on the starboard side1 and the starboard on the port side4 ,it should be here remarked that1 although great speed is essential in the torpedo vessel to come up with the enemy and choose an advantageous position1 it is not advisable to tow the torpedoes1 if it can be avoided1 at a greater speed than #aa knots2 because the strain brought upon the towing gear is excessive1 and the torpedo would require a large addition of ballast to keep it sufficiently immersed to attain the full divergence4 ,there is1 however1 one style of attack in which the highest speed can be maintained1 viz4 by dropping the torpedo alongside in passing4 ,this mode of attack is one of the best1 particularly under cover of darkness1 against a ship at anchor4 ,the position of the torpedo is known1 and the tow line is never in contact with the enemy during the operation2 a skilled hand at the brakes is all that is required1 the vessel keeping a straight course at the highest speed1 passing as close as possible to the enemy1 in order to clear away all obstructions4 ,the tow rope must not be checked by the brake too suddenly4 ,defensive ,purposes4--,the ,harvey torpedo may be used as a means of defence by large ships against a torpedo vessel attacking with that species of submarine weapon1 as the latter would be forced to pass outside the former vessel's torpedo1 and thus decrease the chance of a successful dip4 ,again1 in the case of an attack by the ram1 these torpedoes afford some protection1 as a deterrent4 ,night time4--,though a dark night and tempestuous are favourable to a surprise1 yet in the case of a ,harvey torpedo attack it is essential that the weapon should be seen to dip it at the proper time1 therefore daylight is necessary to this species of torpedo attack4 ,value of the ,harvey ,torpedo4--,the ,harvey torpedo is undoubtedly of considerable value when ably handled1 yet the skill and judgment required is very great1 and can only be acquired by constant practice4 ,description of the ,menzing ,towing ,torpedo4--,this modified form of the ,harvey towing torpedo was designed by ,captain ,menzing1 of the ,german navy1 to remedy what is considered by the ,germans as the chief defect of that weapon1 viz4 its liability to injure friendly vessels1 and also to do away with the necessity of using two torpedoes1 one for each side of a ship4 ,at ,fig4 #aag is shown a plan and elevation of this towing torpedo4 a is the body of the torpedo1 somewhat similar to the ,harvey1 but narrower at the stern1 and bevelled on both sides towards the bow2 b is an iron frame placed in the bow1 capable of being turned either to the right or left2 c is the hole for the introduction of the fuze1 and d is the loading hole2 e is a rudder placed at the stern of the torpedo2 f1 f are levers1 by pressure against which the torpedo may be fired mechanically1 or electrically at will2 these levers are connected to a block of wood fitted with stops to prevent them being pushed too far over2 s and p are two towing ropes1 one on each side of the torpedo1 which pass from its stern through the point of the frame b1 and thence to the vessel1 these are also connected to the rudder e in such a manner that on either of the ropes s and p being tautened the rudder e is turned in the opposite direction2 w is an electric cable1 strong enough to bear the whole pressure of the torpedo when being towed right aft4 ,to diverge the torpedo on the starboard quarter of the ship1 the line s must be slackened1 and the whole towing strain brought on the rope p1 causing the frame b to be pulled over to a knot k in the rope p1 made at the proper position to ensure the torpedo towing at the correct angle from the course of the vessel1 and at the same time causing the rudder e to be turned to starboard2 this is shown at ,fig4 #aag by the dotted lines4 ,to diverge the torpedo on the port quarter1 the towing rope p would be slackened and the whole strain brought on the rope s1 and an action opposite to that already described would be the result4 ,two cork buoys are used1 similar to those employed with the ,harvey torpedo2 one being attached at a distance of #aj feet from the stern of the torpedo1 and the other at such a distance astern that the torpedo would be placed at a distance below the surface to allow of safety to a friendly vessel4 ,illustration3 ,,german ,,and ,,french ,,towing ,,torpedoes4 ,,plate ,,xxxv ,the torpedo is manipulated in a similar manner to the ,harvey1 the circuit being closed at the moment of the first buoy disappearing1 at which time the torpedo would be about ten feet below the surface4 ,the two buoys are together capable of supporting the torpedo1 and thus by means of the second one it may be picked up1 should it be necessary to cut the towing ropes4 ,description of the ,french ,towing ,torpedo4--,the towing torpedo used by the ,french is represented in section and plan at ,fig4 #aah4 a is the body of the torpedo1 formed of wood enclosed in a thin steel case2 b is the head made of cork2 c is the case containing the charge1 which is generally #cc lbs4 of dynamite1 this case is supported by the bolt d resting on the plate e2 f1 f are whiskers1 which are connected to the plate e2 g and h are hollow tubes1 one end of g being attached to the case e1 and one end of h to the rear end of the body of the torpedo a1 and they are so arranged that when the case c is released1 its weight will draw out the tube g1 which slides along the tube h to nearly the full extent of the latter2 k1 k are bolts1 to which the towing sling is attached2 l is the fuze1 and n is a small gun used for firing the torpedo at will4 ,the hole in the plate e through which the bolt d passes is larger than the latter1 so that when the plate is moved backwards by pressure being applied to the whiskers the bolt is freed from support1 and case c attached to it falls4 ,the modes of firing are as follows3-- #a4--,the automatic plan of firing is effected by the tube h1 after it has fallen a certain distance1 corresponding to a depth of #i feet for the case c1 drawing down by means of a line attached to it a plug contained in the body a1 which completes the circuit of the firing battery4 #b4--,the plan of releasing the charge at will is effected by means of the small gun n1 which is fired by electricity1 and by its firing forces back the plate e1 thus releasing the charge1 which is then exploded1 as previously explained4 ,locomotive ,torpedoes4--,by ,locomotive torpedoes are meant those that possess within themselves the power to move through the water1 when once started in a given direction4 ,of this species of submarine weapons1 the following are the most efficient and are the ones most generally used3-- #a4--,the ,whitehead fish torpedo4 #b4--,the ,lay torpedo4 ,invention and ,adoption of the ,fish ,torpedo4--,the idea developed by the fish torpedo is due to an ,austrian marine artillery officer1 who is now dead4 ,in #ahfd1 ,mr4 ,robert ,whitehead1 then superintendent of iron works at ,fiume1 acting upon the suggestions of a ,captain ,lupuis of the ,austrian army1 commenced a series of experiments to ascertain the practical value of the above idea1 the result being a fish torpedo1 commonly called ,the ,whitehead1 which though far inferior to the fish torpedo of the present day1 was then considered to be a fearful and wonderful weapon4 ,the ,austrians were the first to purchase this weapon1 and two years later1 in #ahgj1 ,mr4 ,whitehead came to ,england1 and prosecuted numerous experiments with his fish torpedo under the supervision of several ,english officers1 and on the #hth of ,october of the same year he succeeded in completely destroying an old hulk moored at the mouth of the ,medway4 ,the fairly successful results of these experiments induced the ,english government to purchase the secret and several of ,mr4 ,whitehead's fish torpedoes1 under the following conditions3-- #a4--,the right of manufacturing them in ,england4 #b4--,to be kept fully informed of all improvements1 as soon as made4 #c4--,the right of using all such improvements4 ,and the total amount paid to ,mr4 ,k4 ,whitehead at that time was the sum of seventeen thousand five hundred pounds1 which did not include the sum of two thousand five hundred pounds claimed for the expenses attendant on the ,medway experiments4 ,since then a large number of ,whitehead's fish torpedoes have been purchased from time to time1 especially during the ,turco-,russian war1 when some two hundred were ordered1 also great numbers have been manufactured at ,woolwich4 ,the ,english fish torpedo1 as far as can be ascertained1 is a vastly superior weapon to the ,whitehead fish torpedo1 possessing as it does increased speed1 and therefore far greater accuracy4 ,besides ,austria and ,england1 nearly all the ,european governments have purchased the ,whitehead secret and torpedoes1 but in the case of some of them1 the last two clauses of the ,english conditions of purchase were omitted4 ,illustration3 ,,whitehead',s ,,fish ,,torpedo4 ,,plate ,,xxxvi ,the ,turkish is the only government that has obtained the ,whitehead secret and torpedoes without paying for it4 ,this was managed as follows3-- ,on the night of the #bjth of ,december1 #ahgg1 the ,russians made an attack with ,whitehead torpedoes on an ,ottoman squadron lying in the harbour of ,batoum1 but owing to a want of practical knowledge of the manipulation of such weapons1 no vessels were sunk or damaged1 but two fish torpedoes1 one in perfect condition1 were found the next morning high and dry on the beach at that place4 ,the ,american government have up to the present time not sanctioned the purchase of the costly ,whitehead torpedo1 preferring their own locomotive torpedo1 which will be fully described further on4 ,on a government purchasing the fish torpedo1 a certain number of their naval or military officers are sent to ,fiume in ,austria1 where ,mr4 ,r4 ,whitehead's manufactories are situated1 and where the necessary very exhaustive experiments with his torpedoes are carried out1 and are there thoroughly instructed in the manipulation of these machines1 and are also supplied with a double set of drawings of the various parts of the torpedo4 ,these officers1 and all others whom it may be necessary to initiate into the mysteries of the ,whitehead secret1 are bound on their honour not to divulge it4 ,employment of ,fish ,torpedoes in ,war4--,the fish torpedo has been employed on actual service on three known occasions only1 in two of which it failed to fulfil its deadly mission4 ,on the #bith of ,may1 #ahgg1 a ,whitehead fish torpedo was fired by ,h4,m4,s4 ,shah against the ,peruvian ironclad ,huascar1 but failed to strike her1 owing to the latter vessel altering her course at the moment of the torpedo being discharged4 ,the next instance of the employment of the ,whitehead torpedo was that one mentioned at page #acb4 ,the last and only successful attempt yet made occurred on the #bfth of ,january1 #ahgh1 when the ,russian steamer ,constantine fired a ,whitehead torpedo against a ,turkish guard vessel off the harbour of ,batoum1 and completely destroyed her4 ,description of ,torpedo4--,a general view of the ,whitehead fish torpedo is shown at ,fig4 #aai4 ,it is divided into three parts1 connected together by screws4 #a4--,the charge chamber4 #b4--,the adjustment chamber1 in which is placed what is known as the secret4 #c4--,the air and engine chamber4 ,vertical and horizontal steel fins are fitted for the purpose of maintaining the torpedo in an upright position whilst passing through the discharge tube1 or frame2 the former fins run nearly the whole length of the weapon1 while the latter are considerably shorter4 ,the motive power of the torpedo is compressed air1 forced by means of a powerful steam air compressing pump into a portion of the steel chamber 7#c7 at a tension of upwards of #ajjj pounds to the square inch1 which is equivalent to about sixty atmospheres1 and which by means of a set of small three cylinder ,brotherhood engines1 contained in the steel chamber 7#c71 drives two screw propellers4 ,these engines are capable of exerting a force of forty indicated horses1 and yet only weigh about thirty-five pounds1 from which it will be understood that to attain these results the workmanship and materials employed in their manufacture are of the very highest order and fineness4 ,the torpedo is made of various sizes1 ranging from #ad' long and #ad maximum diameter to #ai' long and #af maximum diameter4 ,capabilities of the ,fish ,torpedo4--,the capabilities of the fish torpedo are as follows3-- #a4--;,if adjusted for a certain depth1 from #e to #ae feet1 and projected from above water1 or if started from the surface1 or if discharged from a submerged tube1 it will rapidly attain that depth1 and maintain it during the run4 #b4--;,if fired in still water1 it will make a straight run in the line of projection1 provided that an allowance has been made for the deflection due to transverse currents4 #c4--;,it can be adjusted to stop after having run any distance up to its extreme range1 and after stopping to sink1 float1 or explode4 #d4--;,its range and speed vary considerably1 according to the pattern of the torpedo4 ---------------------------------------- ------------------------------ ,whitehead ,fish ,torpedo4 ,woolwich ,fish ,torpedo4 ---------------------------------------- --------------------- #ad' long1 #af #ad' long1 #af #ad' long1 #ad #ade' long1 #ad max4 diam4 max4 diam4 max4 diam4 max4 diam4 ,yards4 one screw4 two screws4 two screws4 two screws4 ---------------------------------------- ---------------------------- #bjj 44 44 #bj knots4 #be-a_/d knots4 #bej #i-a_/b knots4 44 44 44 #cjj 44 #ab-a_/d knots4 #ai-a_/d knots4 #bd-a_/b knots4 #djj #h knots4 44 #ah knots4 #bc knots4 #fjj 44 #aa knots4 44 #bj knots4 #gej 44 #aj-a_/b knots4 44 44 #hjj #g knots4 44 #af-a_/b knots4 #ah knots4 #ajjj 44 #i knots4 44 #ae-a_/b knots4 ---------------------------------------- ---------------------------- ,pressure of air in engines varies for distance and speed from #dj atmospheres to #adj atmospheres4 ,placing the ,charge4--,the explosive is generally placed in what is termed the cartridge case1 which case is similar in shape to the interior of the charge chamber 7#a71 and is fixed thereto by means of wooden wedges4 ,ignition4--,the method of ignition is mechanical1 and is arranged as follows3--,extending from the nose of the torpedo to the cartridge case is a tube terminating in a copper case1 in which is placed the priming charge and detonating composition2 within this tube is a steel rod some #b feet long1 fitted with a needle point at its inner end1 and its outer end screwed into a frame2 this frame is capable of moving in and out1 and is connected with a spiral spring which tends to force it1 and consequently the steel rod1 or striker1 inwards4 ,by compressing this spiral spring1 the inner end of the frame is butted against a catch1 by which it is prevented from acting4 ,on this catch being released1 no matter by what means1 the spring is brought into action and forces the frame and steel striker inwards1 the needle point of the latter coming into contact with the detonator fires the priming charge1 and so explodes the torpedo4 ,the foremost extremity of the torpedo1 which is termed the nose piece1 is so fitted that it is capable of being forced inwards1 but in a position of rest its inner edge is just clear of the catch4 ,on a pressure being brought on the nose piece in a direct line with the length of the torpedo1 it will be forced inwards1 the result being the releasing of the catch and explosion of the torpedo4 ,in addition to the nose piece1 horizontal and vertical levers1 or whiskers1 may also be used1 a slight pressure on either of which will similarly effect the explosion of the torpedo2 also cutters for penetrating nets1 c41 are fitted to the nose piece when desired4 ,safety ,wedge and ,key4--,for safety purposes a wedge is employed1 which when in the safety position prevents the catch from acting2 this wedge is so arranged that it may be withdrawn by the action of the machinery after the torpedo has run a certain distance1 and also may be replaced by similar means in the safety position on the completion of the run4 ,as an additional precaution a safety key is used1 which is inserted in the head of the torpedo through the spring of the frame4 ,description of ,adjustment ,apparatus4--,for adjusting the length of range for withdrawing and replacing the safety wedge1 c41 the following apparatus is employed4 ,two cog wheels1 a large and a small one1 are fixed on the upper part of the after end of the torpedo1 just in front of the screw propellers3 the small wheel is fitted with a certain number of teeth1 thirty for instance1 which gears into an endless screw attached to the propeller in such a manner that one revolution of the propeller moves the wheel one tooth1 therefore thirty revolutions would turn the wheel one complete revolution4 ,the big wheel is fitted with much larger teeth than the small one1 and by means of a pin on the latter wheel is moved round one tooth for every complete revolution of the small wheel1 and clamped in this new position by a spring catch1 which is also worked by the pin on the small wheel4 ,in front of these wheels is a stud which works fore and aft in a slot1 and attached to a spring which tends to draw it to the after end of the slot4 ,this stud is connected by means of a wire rod to the valve that admits the compressed air to the engines2 when the stud is in the fore part of the slot the valve is open1 and when in the after part it is closed4 ,adjusting ,length of ,range4--,by means of a lever the spring of the stud is compressed1 and the stud moved to the fore part of the slot2 then the big wheel is moved round until a stud on its face is the required number of teeth above the lever4 ,for every thirty revolutions of the propeller1 and consequently one tooth of the big wheel1 a certain known distance is traversed1 which varies according to the pattern of the torpedo4 ,adjusting ,apparatus4--,when the propeller has made the number of revolutions corresponding to the length of range required1 and consequently has moved the big wheel the number of teeth it was set above the lever1 the stud on the big wheel presses against the lever and so releases the spring in the slot1 causing the slot stud to fly from the fore part to the after part of the slot1 by which action the valve admitting the compressed air to the engines is closed1 and consequently the engines cease to work4 ,attached to the axle of the big wheel is a small brass arm1 which is connected by means of a brass rod to the safety wedge1 and is so arranged that after the required number of revolutions of the propeller1 the safety wedge will be drawn out2 or it may be drawn out at the instant of the torpedo leaving the tube1 carriage1 c4 ,also by means of an additional lever at the fore part of the torpedo1 which is connected by means of a wire rod to the valve that admits the air to the engines1 and by arranging the attachment of the safety wedge to the brass rod from the big wheel1 so that on the wedge being withdrawn it is released from that brass rod1 on the torpedo having completed its run1 the action of closing the valve which admits the air to the engines causes the additional lever to force the wedge into the safety position4 ,torpedo to ,float at ,end of ,run4--,this is due to the difference of buoyancy at the end of a run from what it was at the commencement1 owing to the compressed air being used in working the engines4 ,torpedo to ,sink at ,end of ,run4--,this is effected by means of the adjustment chamber 7#b71 in the after end of which there is a spiral spring valve1 which can be attached to the brass rod on the outside of the torpedo that works the valve which admits air to the engines1 in such a way that on the valve being closed1 and therefore the run of the torpedo completed1 the spiral spring valve is opened1 admitting water to the adjustment chamber 7#b7 of sufficient amount to sink the torpedo4 ,to ,explode the ,torpedo at ,end of ,run4--,this is effected by connecting the vertical firing whisker to the rod which otherwise would be connected to the safety wedge lever1 by which means1 on the valve admitting air to the engines being closed1 a force is transmitted to the vertical whisker instead of to the safety wedge lever1 and consequently the torpedo is exploded4 ,adjusting the ,depth4--,a small wheel1 the face of which is marked in feet1 is placed on the left side of the fore part of the adjustment chamber 7#b74 ,to adjust for depth1 by means of a key turn the wheel until the number corresponding to the depth of run required is opposite the pointer4 ,the torpedo is maintained at the desired depth by means of certain mechanical apparatus contained within the adjustment chamber 7#b71 and which constitutes what is termed the secret of the fish torpedo4 ,this chamber is connected by screws to the foremost and after chambers of the torpedo1 in such a manner that by means of a number of small holes bored round the circumference1 as shown at 7#b71 ,fig4 #aai1 the faces of the chamber are exposed to the pressure of the water1 which varies with the depth to which the torpedo descends4 ,within the adjustment chamber is an endless strong spiral spring1 attached to the after face of the chamber1 and so arranged that after being set to a certain tension1 capable of resisting an equivalent pressure on the outside of the aforesaid face1 any increase or decrease in this exterior pressure will cause the spiral spring to work a rod by which the horizontal rudders of the torpedo are regulated1 and thus the desired depth for which the spring is set is maintained4 ,the course of the torpedo is represented by a series of curves1 above and below the line1 representing the depth it is set for1 these curves gradually decreasing until at #ajj yards' distance from where the torpedo was started the curves are so small that the path of the torpedo is almost identical to that of a straight line4 ,within this adjustment chamber is also placed an automatic balance1 which also assists to maintain the torpedo at the desired depth1 by reason of its swinging forward on the torpedo descending1 and swinging aft on its rising1 which motion is used to regulate the horizontal rudders4 ,the above is merely a general idea of the arrangement used in the ,whitehead fish torpedo1 to enable it to reach and maintain whatever depth it may be necessary to use it at from #e to #ae feet4 ,projecting the ,torpedo4--,the fish torpedo may be projected in various ways1 viz43-- #a4--,through a submerged tube in the stem1 or on the broadside4 #b4--;,from a carriage above the surface4 #c4--;,from the surface4 ,discharging ,torpedo through a ,submerged ,tube in the ,stem4--,in this case a tube is fitted to an orifice in the stem2 this opening is as far below the water line as possible1 and is closed by a watertight cap and a sluice valve2 the inner end of the tube is fitted with a watertight door2 the torpedo being prepared for action is placed inside the tube1 the inner door closed1 and the tube filled with water2 then the watertight cap and sluice valve are opened1 and the torpedo started by means of a piston which is worked by compressed air4 ,this piston can be worked from deck1 and so the torpedo fired at the proper instant4 ,to prevent the torpedo from slipping out of the tube1 a stop is placed in the fore end of it1 which can be withdrawn at the same time as the compressed air is admitted behind the piston4 ,the torpedo being clear of the tube1 the sluice valve and watertight cap are closed1 and the tube emptied of the water1 the projecting piston being at the same time forced back4 ,on the ,broadside4--,in this case1 the discharging tube works inside an iron casing1 through a stuffing box at the inner end1 and in a shield attached to the outer end of the tube4 ,this shield1 placed on the fore side of the orifice1 is of such a length as to protect the torpedo from the pressure of the water passing the vessel4 ,the mode of discharging the torpedo in this case is similar to that used when projecting it through the stem4 ,comparison of the ,stem and ,broadside ,methods of ,projecting the ,torpedo4--,the former method of projecting the torpedo seems the most suitable to specially built torpedo vessels1 but not so to large ironclads1 on account of the difficulty of fitting a tube to the stem of such a ship1 and also that in so doing the efficiency of the vessel as a ram would be impaired4 ,in regard to the accuracy of the firing of the above methods1 both seem equally good1 though in the case of firing on the broadside it would be necessary to prepare carefully calculated tables of deflection1 any mistake in the using of which would be fatal to a successful torpedo shot4 ,projecting a ,torpedo from above ,water4--,in this case an iron carriage is used1 which is fitted with a frame1 in which the torpedo rests2 the outer end of this frame is provided with a lip1 some few feet long1 by which means the rear end of the torpedo is slightly canted up on leaving the frame1 and any undue strain on the tail of the torpedo is prevented4 ,the frame is mounted in the iron carriage in such a way that it can be elevated or depressed by means of a screw1 as in the case of a gun mounted in an ordinary carriage4 ,the torpedo is ejected from the frame by means of a piston as previously explained1 a small reservoir of air being attached to the carriage1 so that it can be used at any port4 ,firing a ,torpedo from the ,surface4--,the torpedo possesses sufficient buoyancy to float with a small portion of its upper surface above water2 such being the case1 it is only necessary to set the various adjustments1 point it in the required direction1 and by hand turn back the lever on the upper part of the weapon 7which opens a communication between the air chamber and the engines71 when it will instantly dart off and very rapidly attain the depth it is set for4 ,method of ,firing a ,fish ,torpedo from a ,boat4--,to manipulate a fish torpedo from a boat1 it may be carried in a light frame1 which can be lowered or raised by means of a pair of davits4 ,when required to discharge the torpedo1 the frame containing it is lowered into the water1 so as to bring the torpedo about two feet below the surface1 the head being somewhat lower than the tail4 ,thornycroft's ,method of ,firing ,fish ,torpedoes from a ,boat4--,another method1 which has been patented by ,mr4 ,j4 ,i4 ,thornycroft1 of the firm of ,j4 ,i4 ,thornycroft and ,co41 steam launch builders1 and which is fitted to the torpedo boats built by them for foreign governments1 is shown in elevation and plan at ,figs4 #abj and #aba4 ,the apparatus consists of two or more bent levers ,a securely and rigidly fixed on a shaft ,b1 which works in bearings fixed on the deck of the vessel ,c from which the torpedo is to be discharged4 ,on the ends of the levers ,a furthest from the shaft ,b are pivoted other levers ,d1 to which the cradle or case ,e for sustaining the torpedo is suspended4 ,the other ends of each of these levers are connected to the vessel by means of rods or tubes ,f1 jointed at each end in such a way that when the shaft ,b is made to revolve in its bearings1 the case containing the torpedo is guided over the side of the vessel and close to it1 and is held in a position convenient for discharging the torpedo1 as shown at ,fig4 #abj4 ,the shaft ,b may be made to revolve by means of ropes ,g and pulleys ,h attached to the levers ,a1 or by hydraulic or steam pressure1 as may be found most convenient4 ,the torpedo case can be towed alongside the vessel if necessary without deranging the apparatus4 ,the torpedo case is carried in the angles of the bent levers1 and is stowed away so that neither it nor the suspending levers project at all beyond the hull of the vessel2 also when lowered1 the levers and suspending rods fold over one another so as to occupy very little space1 and the torpedo is suspended close to the hull4 ,also the torpedo during the operation of lowering as well as when in a firing position remains close to the side of the vessel1 thereby obviating any risk or inconvenience from excessive leverage which would have a tendency to capsize the boat4 ,for especially built torpedo launches1 the above mode of carrying and launching the fish torpedo is certainly the best yet devised4 ,woolwich ,fish ,torpedo4--,in the ,woolwich torpedo1 the engines exert a force of nearly #fj indicated horses1 and work up to #ajjj revolutions per minute2 the total weight of the torpedo fully charged 7#cc lbs4 of gun-cotton7 is about #ejj lbs4 ,illustration3 ,,thornicroft',s ,,boat ,,apparatus ,,for ,,fish ,,torpedoes4 ,,plate ,,xxxvii ,the ,whitehead fish torpedo costs about #chjl41 while the ,woolwich one costs only #cjjl4 ,the ,lay ,torpedo ,boat4--,priority of invention of this torpedo was on the #acth of ,june1 #ahgc1 awarded by the ,commissioners of ,patents to ,mr4 ,john ,louis ,lay1 several other persons having claimed the invention1 among whom was ,colonel ,von ,scheliha1 an officer of the ,russian army4 ,this locomotive torpedo1 or more properly called torpedo boat1 has been for several years adopted by the ,american government1 during which time it has undergone a series of exhaustive experiments1 which has proved it to be a most valuable and efficient weapon of offence and defence4 ,lately the ,russian government have adopted it1 and intend using it extensively in the defence of their harbours1 c4 ,general ,description of the ,torpedo4--,at ,fig4 #abb is shown a longitudinal section of a ,lay torpedo boat constructed and provided with guiding and controlling apparatus1 and with means for propelling it by ammoniacal gas4 ,fig4 #abc is a horizontal section of the same2 ,a is the hull or body of the boat1 which has conical ends ,a#a1 ,a#b1 and is formed of thin plate iron1 or steel1 or other suitable material4 ,the section in the end ,a#a forms the magazine containing the charge of dynamite or other explosive material2 ,a#c is the section containing the gas reservoir or holder2 the compartment ,a#d contains the apparatus for holding and paying out the electric cable2 the compartment ,a#e in the end ,a#b contains the motor engine1 the steering apparatus1 and other parts to be hereinafter described4 ,all of these compartments or sections are separated from each other by means of air-tight bulkheads ,a#f4 ,the torpedo boat may be propelled by means of a single screw1 double screw1 or two screws4 ,in the latter method1 which is shown at ,figs4 #abb and #abc1 the propellers ,b and ,c are made to revolve in opposite directions2 the shaft ,d of the propeller ,b is hollow or tubular1 and the shaft ,e of the screw ,c passes through the same2 these screws are actuated by an engine shown at ,f4 ,h1 ,h are the horizontal rudders1 or side wings1 two forward and two aft2 these wings are mounted on shafts or spindles passing transversely through the boat2 these rudders may be set to occupy a horizontal position1 or a more or less inclined position in the proper direction1 to cause the submerging of the boat by the action of the water on the said rudders as the boat moves forward1 and they are adjusted before starting4 ,n1 ,n are two guide rods1 one aft and one forward1 which project up from the boat to enable the operator to determine its position at any part of its run1 and in the case of a night attack they are provided with lights2 the said rods can be raised or lowered at the will of the operator4 ,q is the electric cable1 which affords a medium of communication between the operator on shore1 c41 and the torpedo boat1 whereby it may be started1 stopped1 steered1 fired1 and has her position ascertained2 this cable is carried in the boat in a coil arranged longitudinally in the air-tight chamber ,a#d in the reel frame ,r1 and is payed out as the torpedo progresses through a tube ,s1 projecting aft under the boat and beyond the rudders and propellers1 so that the said cable will not be fouled by the same2 or it may be payed out through a hollow shaft in the centre of the boat4 ,one end of this cable is connected to a keyboard at the station on shore or on board of the ship or other structure from which the torpedo boats are controlled4 ,this keyboard is provided with a suitable battery or other means for generating the electric current1 as hereinafter described4 ,the said cable is composed of several wires1 each of which is insulated from the others4 ,one of these wires is connected with the mechanism for starting and stopping the boat1 one is connected with the steering apparatus1 one serves for indicating to the operator at all times the exact position of the rudder1 one is connected with mechanism for elevating and depressing the said guide rods1 and one serves for firing the charge in the magazine4 ,the motive power for effecting the necessary movements of the mechanism or apparatus in performing the above operations is obtained from the aforesaid engines1 which are provided with suitable valves arranged in combination with electro magnets1 shunts1 and the devices connected with the said wires of the cable1 as hereinafter set forth4 ,this form of cable has since been replaced by one which consists of two wires only1 the one for performing all of the necessary operations1 exclusive of the firing or exploding of the magazine1 and the other exclusively for this latter purpose4 ,this improvement is effected by employing a series of relays or resistance coils1 or a multiple1 or compound relay in the boat4 ,the advantages gained by this improved form of cable are3-- #a4--;,increased flexibility4 #b4--;,a greater length of cable may be coiled in a given space4 #c4--;,a thicker coat of insulating material may be used1 thereby more perfectly insulating it4 #d4--;,it is much cheaper4 ,two rudders are generally used1 one below and one above the boat1 as shown at ,u1 ,fig4 #abb4 ,these rudders are operated and controlled by means of a small auxiliary engine ,t1 ,fig4 #abb1 which is started1 stopped1 and reversed by the electric current conducted through the cable ,q in connection with magnets attached directly to a valve forming part of the said engine4 ,this valve is so actuated by the magnets that when the current passes in one direction the engine ,t will move the rudder to starboard1 and when the current acts in the opposite direction it will turn the rudder to port4 ,the mechanism for firing the charge in the magazine ,a#a is clearly shown in ,fig4 #abd1 and operates as follows3--,projecting from the front extremity or stem of the boat is a rod or pin ,v1 which extends through a suitable packing box ,w into the said magazine or charge chamber2 when the boat strikes an object1 the said rod is forced inward into contact with the springs or points ,x1 thereby closing an electrical circuit and igniting a cartridge1 shown at ,y1 in the magazine4 ,the charge in the magazine can also be fired at any moment by the operator on shore closing a circuit on the keyboard and thereby cutting out one of two resistance coils placed in the circuit to prevent accidental or premature discharge--that is to say1 there are two resistance coils4 ,the battery is not sufficiently powerful to fire through both resistance coils at the same time4 ,when the boat strikes an object1 the resistance coil in the magazine is cut out by the driving inward of the rod ,v1 as above described2 the battery then fires through the one on the keyboard4 ,on the other hand1 if the operator desires to fire the torpedo boat before she touches the object of attack1 he manipulates the switch to cut out the coil in the keyboard1 the charge then being fired through the coil in the magazine4 ,this arrangement of the two resistance coils is very effectual in preventing accidents4 ,in some instances the magazine is made detachable from the hull of the boat1 so that on striking an object it will descend or drop down in the water before exploding4 ,this modification is shown at ,figs4 #abe and #abf4 ,the magazine ,a99 is attached at its lower side to the boat by a chain or other suitable connection4 ,at its upper edge it is held by a rod a991 as shown in ,fig4 #abe4 ,this rod is fitted to slide in dovetailed bearings1 as shown at b991 and when this magazine is in its place on the boat the said rod is engaged with a catch or stop c991 but when the said rod is driven against any object it is forced back and released from the said catch or stop1 and the magazine then drops1 as in ,fig4 #abf1 and is fired4 ,to effect the firing a ball d99 is used and placed in a tube containing two springs or plates e99 and arranged in an upwardly inclined position1 as shown in ,fig4 #abe1 one of the said springs being connected with the cable and the other with a wire that passes through the cartridge to earth4 ,while the magazine is in the position shown in ,fig4 #abe the circuit is incomplete1 but when the magazine drops the said ball falls into the position shown in ,fig4 #abf2 the circuit is then completed1 and the magazine is fired4 ,the electrical or electro-magnetic apparatus for generating1 directing1 and controlling the currents1 whereby the above-described operations are effected1 may be of any suitable kind1 the following being the form of apparatus usually employed4 ,a battery r1 shown at ,fig4 #abg1 consists of any desired or requisite number of cells constructed and arranged in any suitable manner1 and connected by proper conducting wires with the keyboard s4 ,the latter is provided with a series of pole changers s#a1 s#b1 s#c1 s#d1 and switches s#e1 s#f1 and is shown in ,fig4 #abh4 ,each of these pole changers is arranged to effect and control one of the above-named operations1 and is therefore connected with one of the aforesaid insulated wires forming the cable4 ,for instance1 the pole changer s#a effects the starting and stopping of the propelling engine2 s#b controls the steering apparatus2 s#c is connected with the steering index2 s#d operates or adjusts the aforesaid guiding rods2 and the switches s#e1 s#f control and effect the firing of the charge in the magazine4 ,illustration3 ,,lay',s ,,locomotive ,,torpedo4 ,,plate ,,xxxviii ,illustration3 ,,lay',s ,,locomotive ,,torpedo4 ,,plate ,,xxxix ,the connections between these pole changers and switches1 and the apparatus they operate or control on board the boat1 are as follows--that is to say1 the said propelling engines have a throttle valve1 which controls the admission of the gas from its generator or reservoir to the cylinders of the said engine1 and in combination with this valve in the boat there is a shunt and set of electro magnets4 ,the armature of the latter is connected with a lever1 which is pivoted so that the action of the electric current in one direction through these magnets will pull one end of the said lever down1 and the action of the current in the other direction will pull its other end down--that is to say1 by reversing the current through these magnets the movement of the said lever is reversed2 and this lever1 connected by suitable means with the slide of the said throttle valve1 will open or close the same1 and thereby start or stop the engine as required4 ,for operating and controlling the above-described steering apparatus1 and indicating the position of the rudder to the operator on shore1 the following devices are employed1 in combination with the pole changers s#b1 s#c on the keyboard3--,the pole changers are geared together by insulated toothed wheels1 which are fixed on the spindles or axes of the said pole changers1 so that the latter work accurately together and maintain the same relative positions to each other4 ,the pole changer s#b is connected by one of the said insulated cable wires with a shunt on board the boat1 which shunt is connected with a set of magnets arranged in combination with the valve of the engine that drives the steering apparatus1 and which valve is reversed or opened and closed by the reversal of the currents through the said magnets1 as above described1 and the said engine moves the rudder to port or starboard at the will of the operator4 ,in order that the operator may know the exact position of the rudder at any moment1 a series of pins or projections fixed on an arc or other portion of the rudder stock1 and arranged in combination with an insulated spring projecting into the path of the said series of pins1 are employed4 ,this spring is connected by one of the cable wires with the pole changer s#c on the keyboard1 which is geared with and moves in unison with the pole changer s#b1 so that the electric current that controls the steering engine1 and the current that returns the indication of the rudder's position1 will both be reversed simultaneously4 ,a separate battery is connected with the index on the said keyboard1 whereby a constant current is maintained between this index and the indicating apparatus on the boat4 ,the current passing from the said spring to the shore is made to indicate the position of the rudder by the index on the keyboard by the contrivance shown in ,fig4 #abi4 ,this contrivance consists of a set of magnets w1 which have a vibrating armature w#a pivoted to oscillate between them4 ,one end of the armature lever is provided with insulated spring pawls w#b1 which take into ratchet wheels w#c4 ,on the same shafts on which these ratchet wheels are fixed are wheels w99 formed with insulated teeth and geared with each other4 ,the shaft of one of these wheels is geared by bevel pinions w#d with a vertical shaft w#e1 to which is attached the index needle or finger x99991 ,fig4 #abh4 ,therefore it will be obvious that this index finger is placed in connection with the aforesaid spring and series of pins attached to the rudder yoke on board the boat4 ,now it will be obvious that when the rudder is turned in either direction these pins will come successively in contact with the said spring1 and at each contact and separation the circuit will be made and broken1 and an impulse will be transmitted through the cable1 whereby a corresponding movement will be transmitted to the said index finger or pointer x9999 on the keyboard4 ,the pole changer s#d is connected with another of the insulated wires of the cable1 which on board the boat is connected with a shunt and set of magnets arranged in combination with the aforesaid cylinders that operate the said guiding rods1 so that by sending the current in one direction the said rods will be raised1 and by sending the current in the opposite direction the said rods will be lowered4 ,the switch s#e is connected with another of the said insulated wires of the cable1 which forms the circuit1 including the aforesaid two resistance coils4 ,by adjusting this switch the operator completes the circuit through the two resistance coils1 and then1 but not till then1 the charge can be exploded1 either by the operator1 or by the action of the firing pin or rod when the same is driven in and cuts out the other resistance coils as above described4 ,the resistance coil ,x#a1 ,fig4 #abd1 is connected to the binding screws #i1 #aj by the wires #g and #h4 ,these binding screws are in metallic connection with the two springs ,x1 but otherwise they are carefully insulated4 ,one pole of the fuze ,y is connected to the binding screw #aj1 the other put to earth through the body of the boat1 as at ,e2 the main wire #aa is connected to the binding screw #i4 ,now when the operator cuts out the resistance coil at the firing station1 which is done by moving the switch s#f1 the electric current is sufficiently powerful to ignite the fuze ,y through the resistance coil ,x#a1 so that at any moment the torpedo may be exploded by the operator on shore1 or by the contact between the torpedo and the attacked vessel the rod ,v will be driven in1 and1 coming in contact with the springs ,x1 will bridge over the space that originally existed between them and so cut out the resistance coil ,x#a1 and the torpedo will be exploded automatically4 ,capabilities of the ,lay ,torpedo ,boat4--,the capabilities of the ,lay torpedo boat are as follows3-- #a4--;,it may be launched from the shore1 a vessel1 or a structure1 and be kept under observation1 and accurately guided or directed to the ship or other object to be attacked2 and it may be exploded at any desired moment1 or it may be caused to return to the original point of departure without being fired4 #b4--;,it may be totally and instantaneously submerged to prevent its destruction or capture by the enemy1 and it may be raised to the surface1 as soon as the danger has passed1 in a condition fit for immediate action4 #c4--;,it may be used as a tug or towing boat to take out a number of torpedoes1 which may be sunk and exploded when desired4 #d4--;,it may be used in connection with certain apparatus to clear away obstructions found to prevent the entrance of ships into harbours1 and it may also be used to clear harbours of mines1 c4 ,launching the ,lay ,torpedo ,boat4--,for facilitating the launching and controlling of the ,lay torpedo boats1 a structure or submarine fort is used4 ,this structure may be square1 or oblong1 and may be made to carry any number of the torpedo boats4 ,the body is constructed of plate or sheet iron of suitable strength and stiffened with angle iron1 or otherwise1 and divided longitudinally or transversely into watertight compartments1 into which the water is admitted to sink the said structure4 ,at the top or upper side1 cylinders or tubes are placed1 each of which is capable of containing and launching one of the torpedo boats4 ,at the forward end of each tube is a door1 or cover secured to a rod or shaft fitted to turn in suitable bearings2 this rod or shaft is provided with an arm which is connected to the piston rod of an engine worked by gas contained in a reservoir1 or by other suitable means4 ,the slide or other valve which controls the admission of the gas1 c41 to this engine is arranged in connection with electro magnets1 connected by a suitable cable with a keyboard on shore1 or wherever the operator's station may be4 ,by sending an electric current through this cable in one direction through the electro magnets1 the door is closed2 and by sending such a current in the opposite direction it is opened4 ,the cables carried in the torpedo boats1 and through which the mechanism on board each torpedo boat is operated and controlled1 are also in this case connected with the keyboard1 which must be provided with a number of sets of pole changers and switches1 or equivalent devices1 corresponding with the number of boats to be controlled by means of the said keyboard4 ,this apparatus will form a very convenient adjunct to fortifications or stations liable to be attacked by sea4 ,the said fort may be prepared for use by placing torpedo boats in the said tubes1 and may be kept floating until the enemy's ships have arrived closely enough to permit the determination of the point where the said fort can be most advantageously located for operating against the said ships4 ,the fort is then towed to this point1 or taken as near as possible thereto on rails1 and towed the remainder of the distance4 ,it is then submerged1 and will be ready for immediate operation4 ,the said fort is provided with suitable valves for the admission of water to sink the same1 and with means for forcing in air through the pipe ,p99 to expel the water when the fort is to be raised4 ,when it is desired to launch either of the said torpedo boats1 the door of its tube or cylinder is first opened by sending a current through the cable that controls the door1 as above described4 ,then the current is sent through the boat's cable to start her propelling engines4 ,the said boat will then emerge from the cylinder or tube and will rise to the surface1 or as near the surface as may be desired1 and may then be directed and controlled by the operator at the keyboard1 as previously described4 ,and one after another of the said torpedo boats may be thus launched and exploded1 without giving to the enemy any clue to the point or position from which they are being sent4 ,illustration3 ,,lay',s ,,locomotive ,,torpedo4 ,,plate ,,xl ,launching the ,torpedo from a ,ship4--,the method of launching the ,lay torpedo boat from an ironclad or other large ship is shown at ,fig4 #acj4 ,the tubes or cylinders ,s in which the torpedo boats ,a are held are1 in the apparatus shown at ,fig4 #acj1 closed at their inner ends by plates1 or covers ,s#a1 which are provided with suitable water-tight and insulating packing boxes ,s#b for the passage of the electric cables of the said torpedo boats1 each cable being connected with the keyboard1 which is placed in any convenient part of the ship1 and at their outer ends the said tubes are furnished with strong and well-fitted slide valves1 or sluice gates ,s#c1 which are opened by screws1 connected by gearing with a hand wheel1 and shaft ,s#d1 ,s#e1 for the admission and exit of the said torpedo boats4 ,also these cylinders are provided with packing pieces at their sides1 arranged to be pressed by screws or otherwise up to the sides of the torpedo boats in these cylinders1 and thereby hold them firmly and immovably in rough weather4 ,the ,method of ,sinking and ,raising a ,lay ,torpedo ,boat4--,the apparatus by which this is effected is shown at ,fig4 #aca1 which is a longitudinal section of a portion of a torpedo boat4 ,the hull ,a of the torpedo boat is provided with a water chamber l1 which has holes or apertures l#a in the bottom of the same1 and is also provided with an air cock at l#b4 ,in connection with this chamber is arranged a small cylinder m1 provided with a piston m#a1 whose rod m#b is attached to the lever of the said cock4 ,a spiral spring m#c is provided to resist the inward movement of the said piston4 ,the said small cylinder m is connected by a pipe m#d with a valve chest1 in which is arranged a slide valve m#e4 ,the said slide valve is connected by a rod or rods to the lever or levers m#f1 whose fulcrum is at m991 and the said levers are connected by the links or rods m#g with the armatures of electro magnets n1 which are included in the circuit of the cable1 whereby the boat is controlled from the keyboard at the station2 o is a pipe extending from the said valve chest to the aforesaid water chamber l2 p is a feed pipe by which gas is conducted from the reservoir or generator to the valve chamber4 ,when it is desired to sink the torpedo boat an electric current is sent in one direction through the said magnets1 and thereby operates the slide valve to admit gas to the cylinder m in front of the piston m#a1 which is thus forced inward and opens the air cock l#b4 ,the opening of this cock permits the escape of the air from the water chamber l1 and consequently the entrance of water through the apertures l#a1 and the boat then immediately sinks4 ,when it is desired to raise the boat a current is sent in the opposite direction through the said electro magnets1 thereby operating the said valve and piston in such a manner as to close the cock l#b and open the port o#a and the pipe o1 thereby allowing the gas to pass from the valve chamber into the compartment l2 this gas by its pressure expels the water from the said compartment1 and the boat then having its normal buoyancy restored immediately rises to the surface4 ,the ,lay ,torpedo ,boat used as a ,tug to take out a ,number of ,small ,torpedoes4--,this arrangement is shown at ,figs4 #acb and #acc4 ,the small vessels or torpedoes are designed to be first sunk and then exploded1 chiefly for clearing harbour or the like of mines or other obstructions4 ,these results are accomplished by means of the following devices and arrangements1 that is to say1 each of the small vessels or torpedoes ,f is provided with apparatus which is included in an electrical circuit formed by a suitable insulated cable ,g1 extending throughout the train of small vessels or torpedoes ,f4 ,one vessel of this train1 preferably the rear one1 is connected with the station by an electrical cable ,h1 which is payed out from a coil or coils1 or a reel or reels1 in the said vessel as the same travels through the water4 ,this cable ,h connects with the cable ,g1 which is connected with the towing boat ,a1 and passes through the series of boats ,f to the said cable ,h4 ,one wire of the said cable is arranged in combination with sealed or covered apertures in the bottom of a compartment or compartments of these small vessels ,f1 as shown at ,i1 the covers of these apertures being so formed as to be ruptured or destroyed by the explosion of a cartridge or cartridges placed in the said compartment or compartments4 ,when a current of electricity is sent through the aforesaid wire of the cable it will explode the said cartridges and open the apertures1 thereby admitting water into the said compartments so that the vessel ,f will sink4 ,the cable ,g that passes through the train of torpedoes or vessels ,f is so arranged that when a current passes through the other wire of the said cable it will fire cartridges placed in the charge chambers or magazines of the said small vessels1 as shown at ,j4 ,the part of the cable or towing line ,g1 which connects the towing boat ,a with the train of small boats or torpedoes ,f1 is attached to a hook or other device1 which can be disengaged by sending a current through the cable ,k1 connecting the boat ,a with the shore or other station4 ,it will be understood that when being used for this purpose the said boat ,a is not or need not be charged with explosive material4 ,illustration3 ,,lay',s ,,locomotive ,,torpedo4 ,,plate ,,xli ,the aforesaid towing boat ,a takes the train of torpedoes ,f to any required position4 ,it is then disengaged from the train1 leaving the said small vessels or torpedoes ,f floating in such position4 ,then by sending a current first through one wire of the cable ,h the boats ,f are first sunk by the explosion of the cartridges and opening of the apertures1 as above described4 ,they may then be discharged immediately by sending a current through the other wire of said cable ,h and firing the cartridges in their magazines1 or they may be left submerged to form mines which may be exploded at any desired moment4 ,the said small vessels or torpedoes may be provided with vertical rods to indicate their position to the operator at the station2 these rods are shown at ,l1 and they should be made hollow to allow the air in the water compartments or chambers to escape to permit the water to enter the same when the vessels ,f are to be sunk2 or other suitable provision may be made for the escape of the air from these compartments4 ,the said vessels ,f are preferably made cylindrical with conical ends1 and are provided with suitable insulating and water-tight packing boxes1 as shown at ,f#a for the cable ,g to pass through at the stem and stern of each vessel4 ,the ,lay ,torpedo in ,clearing ,obstructions4--,for this purpose the torpedo boat is provided with an apparatus1 shown at ,figs4 #acd and #ace1 in combination with the electric cable1 whereby the said boat is controlled and guided1 and there is arranged in the boat ,a a compartment ,a#c1 from which extends down into the water a line or rod ,u1 provided at its outer end with a hook or claw ,u#a1 properly formed to take hold of any chain or bar with which it may come in contact4 ,in the said compartment ,a#c1 and upon the upper end of the said line or rod ,u1 is placed a small case or cylinder ,u#b containing a charge of dynamite or other explosive material and a cartridge or fulminating cap1 or a bottle of sulphuric acid1 surrounded with a certain quantity of chlorate of potash and sugar4 ,this case or cylinder ,u#b is shown detached and drawn to an enlarged scale at ,fig4 #ace1 and it will be seen that the said case is provided with a tube #a containing a cartridge1 or a phial filled with explosive substance at #b1 and a ball or weight at #c4 ,the said case is fitted to slide upon the said line or rod ,u1 and when placed at the upper end thereof and not held or retained will slide to the lower end of the same4 ,in the said compartment ,a#c is arranged at ,u#d an electro-magnetic apparatus1 included in the circuit of the said cable1 and connected with a bolt or catch which in its normal position holds the said explosive case and prevents its running down on the grappling line or rod ,u4 ,this explosive case is also provided at its lower end with a grappling hook ,u#e4 ,when the grappling hook ,u#a1 on the lower or outer end of the line or rod ,u1 engages with any obstruction the boat will be stopped1 and this stoppage will be indicated on the keyboard4 ,the operator by this indication is apprised of the stoppage of the boat by an obstruction1 and by sending a current through the cable by means of a switch provided for this purpose on the keyboard he can immediately release the explosive case ,u#b1 which runs down the line or rod ,u1 and engages by its grappling hook ,u#e with the hook ,u#a4 ,the line or rod ,u is then disengaged from the boat ,a1 and the explosive case ,u#b turns or falls over4 ,as it turns over the ball or weight #c contained in the tube #a drops on the said phial #b1 fractures it1 and thereby allows the acid to mix with the explosive or fulminating charge and explode the case ,u#b4 ,this explosion will rupture or destroy the obstructing chain or bar1 so that the ironclad ships or other vessels can pass freely and safely into the harbour or beyond the point where it was intended to stop them4 ,used to clear away ,mines and ,electric ,cables4--,for this purpose there is an implement ,v provided1 ,fig4 #acf1 somewhat of an anchor form1 but with four or any desired number of arms ,v#b extending outward at a suitable angle from its shank ,v#a4 ,in the neck of each of these arms are fitted two small plain or toothed discs ,v#c1 which are so arranged as to present their teeth to any object lying in the angle or corner formed by and between the arms ,v#b and shank ,v#a of the said implement1 as shown at ,w4 ,in using this implement it may be attached to a line or cable coiled in the torpedo boat1 which1 in this case1 is used without being charged with explosive material1 and is sent in advance of any ship that has to enter or pass through the suspected water4 ,this line must be arranged in combination with a detaching apparatus controlled by electro-magnetic apparatus included in the circuit of the cable which connects the torpedo boat with the keyboard at the operating station4 ,illustration3 ,,lay',s ,,locomotive ,,torpedo4 ,,plate ,,xlii ,by sending a current from the station the operator releases the said implement or its line from the detaching hook or holding device4 ,the said implement then sinks to the bottom2 then the said boat returns to the ship1 paying out the said line as she so returns4 ,the end of this line is then taken by a steam tug or other vessel1 and the said grappling implement is thereby dragged along through the water over which the ships are to advance1 thus breaking any wires or cables that may be in its course4 ,this operation is shown at ,fig4 #acg1 in which ,a is the towing boat1 ,k the controlling cable1 ,v the said implement1 ,v99 the line attached to the implement ,v1 ,x ,x submerged mines1 and ,x#a ,x#a are the mine cables4 ,in some instances it may not be practicable to reach the enemy's ship or other object of attack directly from the station to which the torpedo boat is connected1 and from which it is controlled4 ,in this case a small boat1 c41 is used in addition1 which should be so arranged as to present to the enemy's view as slight a surface as possible4 ,this mode of attack is shown at ,fig4 #ach1 where ,a is the torpedo boat1 and ,n is the small auxiliary boat4 ,this boat ,n is provided with a keyboard and battery like that described at page #add1 and the electric cable ,l1 carried on and payed out from the torpedo boat ,a1 is connected with the keyboard4 ,the boat ,n is also attached to and towed by the torpedo boat ,a by the tow line ,o2 and the torpedo boat is steered and guided by means of the said keyboard in the boat ,n4 ,the auxiliary boat is designed to contain two men1 who lie down1 one at the bow1 the other in any convenient position abaft him2 the latter has control of the keyboard1 while the former by the aid of a telescope keeps the torpedo boat in view1 and transmits his orders to the man at the keyboard4 ,on arriving at such a distance from the enemy as to render an attack practicable1 the tow line ,o is disengaged1 and the torpedo boat ,a1 guided and controlled1 and fired from the boat ,n4 ,the torpedo boat being exploded1 the auxiliary boat can be rowed back to the station or ship to which it belongs4 ,by this means the range of action of the torpedo boat is greatly extended1 and with comparatively slight danger to those employed in making the attack4 ,a more recent form of the ,lay torpedo boat is shown at ,figs4 #aci1 #adj1 and #ada1 where ,fig4 #aci is a plan or top view of such a boat1 ,fig4 #adj is a side elevation of the same1 and ,fig4 #ada is a midship section on the line x x4 ,a is the hull of the boat1 a is the main or central portion of the said hull1 b1 b are side or auxiliary portions of the same4 ,these parts a and b may be oval or circular in transverse section2 they are constructed of thin steel or other suitable sheet metal1 and secured together by riveting or bolting4 ,the side or auxiliary portion b form the reservoirs or chambers for the gas2 they also serve to contain the propelling engines4 c is the magazine1 d the chamber or compartment for containing the coiled cable1 e is the compartment containing the electrical steering and other apparatus1 f is the firing rod or pin1 g is the water ballast chamber1 h is the cable1 i the paying-out tube1 j1 j are the screws or propellers which rotate in opposite directions1 and k1 k are the sight or guiding rods4 ,the parts of the apparatus or mechanism whereby the various operations of the torpedo boat are effected are connected to the cable and controlled by electric currents transmitted from the station through the cable1 as previously described4 ,the ,lay torpedo boat weighs about #a ton1 its length is #bc feet1 and speed #ab knots per hour4 ,spar or ,outrigger ,torpedo4--,by a spar or outrigger torpedo is meant a torpedo which is carried at the end of a pole or spar projecting from a boat or vessel1 and which may be fired either by contact or at will4 ,this system of submarine offence has up to the present time been the only one that has successfully stood the crucial test of actual warfare4 ,during the civil war in ,america the spar torpedo attack was resorted to by the ,confederates and ,federals1 principally by the former1 the result being the loss of two large men of war and severe injury to several other ships composing the ,federal fleet1 and the loss of one vessel of war belonging to the ,southerners4 ,the spar torpedo was also used on several occasions by the ,russians in their attacks on the ,turkish ships in the war of #ahgg-h1 but in only one attempt was it the means of sinking a ,turkish vessel4 ,description of ,mc,evoy's ,duplex ,spar ,torpedo4--,at ,fig4 #adb is shown a sketch of ,captain ,mc,evoy's improved patent duplex spar torpedo1 which is the form most generally used at the present time1 and which seems to fulfil all the requirements of such a submarine weapon1 viz43-- #a4--;,handiness1 at the same time capable of containing a charge of gun-cotton sufficient in contact to destroy the most powerful vessel afloat4 #b4--;,certainty of action4 #c4--;,capable of being fired either on contact or at will4 #d4--,mode of attaching the spar simple and very secure4 ,illustration3 ,,lay',s ,,locomotive ,,torpedo4 ,,plate ,,xliii ,in ,fig4 #adb1 a is the case1 capable of containing some #cc lbs4 of gun-cotton2 b is the tube through which the three wires w1 w#a1 and w#b are led2 c is the socket in which the wooden or steel spar is introduced and secured1 d is the striker1 which is attached to a brass contact plate within the head of the case a in such a manner that any pressure either on the head or side of the striker d will force the aforesaid plate in contact with the two studs to which the battery wires are attached2 e is a cradle affixed to the striker d to ensure its action on contact being made by the torpedo with the attacked vessel2 the explosive is inserted at f1 the socket c being made to screw on and off4 ,when a hollow steel spar is used1 the battery wires are sometimes led through the interior of the torpedo and the spar1 by which means they are well protected2 the only objection to this method of leading the wires being the probability of injury to them1 should the spar be broken on contact1 or by a shot4 ,mc,evoy's ,arrangement of ,torpedo ,wires4--,at ,fig4 #adc is shown the arrangement of wires as devised by ,captain ,mc,evoy1 whereby the spar torpedo may be exploded at will or on contact4 c and z are the poles of the firing battery1 to which are attached respectively the wires d and d#b2 f is the fuze1 which is placed in the centre of the charge1 and to the poles of which the wire d#b is attached1 the other end of this wire being connected with the stud s2 to the stud s#a is attached the other end of the wire d1 and at the point c in the same wire is inserted a contact breaker2 another wire d#a is connected to the wires d and d#b at the points r and r#b respectively1 and at the point k in this same wire is inserted a firing key1 which latter is shown in section at ,fig4 #add1 from which the mode of connecting the two ends of the wires and of using the key will be at once apparent4 ,the contact breaker is somewhat similar to the firing key1 but there is no spring in it1 contact being made or broken by screwing the two parts together or apart4 ,the object of the contact breaker is to prevent the torpedo being exploded by contact1 and so to place the control of the weapon entirely in the hands of the operator4 ,as will be seen from ,fig4 #adc1 if contact is broken at c1 it is impossible to fire the torpedo unless the firing key k be pressed in2 but should contact be made at c1 then either by means of the firing key k1 or by the torpedo striking the hostile vessel1 its ignition will be effected4 ,the foregoing method of arranging the spar torpedo wires is certainly very neat and effective1 and is at the present time in extensive use4 ,as yet it has not been adopted by the ,english government1 they still preferring to fire the spar torpedo at will alone4 ,the different methods of manipulating the spar torpedo from boats will be described in the following chapter4 ,general ,remarks on ,offensive ,torpedoes4--,the torpedoes that have been described in this chapter are the only ones that at the present time can be considered as having been proved to be practically useful1 and which in future wars may be employed against ships with some chance of success4 ,the spar1 the ,whitehead fish1 and the ,harvey towing torpedo have each been subjected to the test of actual service1 the former weapon being the only one that has under those conditions been successfully used4 ,taking this fact into consideration1 also the high pitch of excellence that has been attained in the construction of steam torpedo boats1 and also the results of the numerous exhaustive experiments that have been from time to time carried out in ,england1 ,america1 and ,europe1 with various modifications of the locomotive1 towing1 and spar torpedoes1 there can be no two opinions as to which of the numerous species of offensive submarine weapons is the most practicable and effective1 and that is the spar or outrigger torpedo4 ,to manipulate successfully locomotive and towing torpedoes in an attack against hostile vessels1 the operators must be not only unusually fearless and self-possessed1 but also must possess a thorough practical knowledge of the complicated method of working and manoeuvring those weapons--in fact1 they must be specialists2 whilst in the case of the spar torpedo1 which may be fired by contact1 it is only necessary to employ men capable of handling a boat well1 and possessed of dash and pluck1 to ensure an attack by such means being generally successful4 ,of course under some circumstances1 such as in a general action1 when the locomotive and towing torpedoes are manipulated from specially constructed torpedo vessels1 they will prove of great value1 and the fish torpedo fired from a boat1 in close proximity to the attacked vessel1 in smooth water1 and unmolested1 would sink a vessel which under the same circumstances1 owing to her being protected by booms1 might prove impregnable to a spar torpedo attack2 but such favourable conditions will not often occur in war time4 ,illustration3 ,mc4 ,,evoy',s ,,duplex ,,spar ,,torpedo4 ,,plate ,,xliv ,as an offensive submarine weapon of defence1 the ,lay torpedo boat should prove of real value2 and also manoeuvred from specially constructed vessels1 it seems capable of being used in a variety of ways4 ,as yet little is known of this weapon1 all the experiments carried out with it having been confined to ,america2 but now that ,russia has adopted it1 and one or two have also been secured by the ,peruvians1 its practical value will become more generally known4 ,,chapter ,,vi4 ,,torpedo ,,vessels1 ,,boats1 ,,and ,,submarine ,,boats4 ,,employment of ,torpedo ,ships4--,torpedo ships1 that is to say1 sea-going vessels1 very fast1 handy and impregnable1 specially designed to carry and operate offensive submarine weapons1 such as locomotive1 towing1 and the spar torpedoes1 especially the former1 are now considered as a necessary and valuable adjunct to a fleet1 their special work being to give the coup de grce to disabled ironclads in a general action2 they will also be used to attack the ships of a blockading force1 and against rival torpedo vessels4 ,as a general rule these torpedo ships will be armed with the ram and torpedoes only1 heavy guns being dispensed with1 though the ,nordenfelt and other machine guns will be considered necessary4 ,the ,german ,torpedo ,vessel ,uhlan4--,this torpedo vessel was built in ,germany by the ,stettin ,engine ,company1 and launched in #ahgf4 ,she is armed with a contact torpedo charged with dynamite carried on a #aj-;foot ram1 lying deeply under the water line4 ,to protect the vessel from the effects of the discharge of the torpedo1 she is built with two complete parts1 sliding one within the other1 and having a considerable extent of intermediate space between them4 ,this space is filled with a tough and elastic material 7cork and marine glue71 which even in the case of the bows being carried away1 would afford a second line of resistance4 ,the ,uhlan carries an engine of one thousand indicated horse power4 ,the steam is supplied by ,belleville's tubular generator4 ,these engines occupy by far the greater space of the vessel1 only a very small portion being left for her crew and coal4 ,this great power of the engines is necessitated by the fact that she has to be driven at a very high speed1 at the same time she has a very great draught1 also the greatest facility of steering has to be attained2 hence the proportion of width to length1 #be to #gj feet4 ,in order to save the crew at the worst1 a raft is constructed1 which is also filled with a mixture of cork and marine glue1 and is placed near the helm4 ,the mode of operating with the ,uhlan is as follows3-- ,the dynamite torpedo is affixed to the point of the ram by the aid of divers4 ,the rudder is then fixed1 and the crew opening a wide port on the vessel's side1 jump on the aforesaid raft4 ,the steamer then rushes forward1 and explodes its torpedo in contact with the hostile vessel4 ,the crew hold on to the torpedo ship1 and in case she is not injured board her again and repeat the manoeuvre1 if necessary4,m ,this is a novel form of torpedo boat1 but does not seem to be a very practicable method of torpedo attack4 ,admiral ,porter's ,torpedo ,ship ,alarm4--,the ,alarm torpedo ship was built from plans designed by ,admiral ,david ,d4 ,porter1 ,u4,s4,n4 ,her total length1 which includes a ram #cb feet long1 is #agb feet2 her beam is #bg feet #f inches1 and her draught of water is #aa feet4 ,she is built of iron on the bracket plate system1 that is to say1 she has a double hull1 one shell being constructed inside the other4 ,her double bottom is divided into a number of water-tight compartments4 ,the whole interior of the vessel is also built in compartments1 which may be hermetically closed1 so that in case of both the shells being ruptured1 it would still be impossible to fill the entire ship with water4 ,she is steered by the same apparatus which propels her1 viz4 the ,fowler wheel1 which is illustrated at ,fig4 #ade4 ,this wheel turns on a vertical shaft1 and its paddles are feathered by an eccentric cam in such a manner that at one part of their revolution they have a pushing and drawing action on the water1 while at another part they present only their edges4 ,in fact it is simply a feathering paddle wheel1 turned horizontally instead of vertically4 ,by suitably turning the cam wheel1 which is done from the helm1 the feathering of the paddles is caused to occur at different points2 and in this way the vessel may be turned1 or rather her stern twisted around1 as if on a pivot4 ,at the same time1 by suitably adjusting the paddles1 the ship goes ahead1 or astern1 the engine meanwhile running in the same direction4 ,by the apparatus above described it is considered that the ,alarm is afforded not only a means of speed1 but of being handled with the utmost readiness1 which latter is absolutely essential in such a vessel1 as she must always meet her antagonist bows on4 ,the steering is accomplished from the wheel house located aft on the deck1 or below deck1 as all the appliances in the wheel house for steering1 c41 are duplicated below4 ,by means of a hand lever beneath the wheel1 steam is admitted to a small auxiliary engine which works the cam that adjusts the paddles4 ,then by turning the horizontal hand wheel in either direction1 the helmsman controls the movement of the cam1 as desired4 ,just above the wheel is a dial with a pointer1 which enables him to note the position of the paddles1 and so adjust them as ordered4 ,inside the wheel house there are also devices for communicating with the men working the bow gun1 and with those managing the torpedoes4 ,her ,armament--,engines4--,at ,fig4 #adf is shown the spar and mode of working it4 ,it consists of a long hollow iron cylinder lying on its supports between decks4 ,its outboard end rests in a kind of trough1 and to this extremity the torpedo is fixed4 ,the spar is controlled by means of tackles and a steam winch4 ,the side spars are #ah feet1 and the bow spar #cb feet in length4 ,if the hostile vessel is defended by torpedo guards1 by means of a mechanical contrivance the torpedo signals the fact1 and is not exploded until the vessel has forced the obstructions4 ,the engines of the ,alarm are compound1 with four cylinders1 the condenser being placed between them4 ,there are four cylindrical tubular boilers with an aggregate heating surface of #d1fjj square feet4 ,her speed is about #af knots4 ,her upper deck is only #c feet above the water4 ,she is fitted with an electric light1 and also with machine guns on her broadside4,n ,this is undoubtedly a most formidable vessel1 both as a ram and a torpedo ship1 and if capable of performing all that is expected of her1 will prove a valuable addition to the ,united ,states ,navy4 ,illustration3 ,,the ,,alarm ,,torpedo ,,ship4 ,,plate ,,xlv ,captain ,ericsson's ,torpedo ,vessel ,destroyer4--,this torpedo vessel was devised and built by ,captain ,john ,ericsson4 ,the ,destroyer is #acj feet long1 #aa feet deep1 and #ab feet beam1 extreme2 both ends of her hull are precisely alike1 and terminate with very fine wedges4 ,the rudder is attached to a vertical wrought iron post welded to a prolongation of the keel1 just abaft the propeller1 as shown at ,fig4 #adg4 ,the tillers consist of thin plates of iron riveted on opposite sides of the rudder1 a few inches from its bottom4 ,these tillers are operated by straight rods connected to the pistons of horizontal hydraulic cylinders of #e inches diameter1 which are attached to the sides of the keel4 ,the steering gear by the above arrangement is placed #aj feet below the water line1 while the top of the rudder is #f feet below the same1 and thus perfect security is afforded to this most important feature of a torpedo vessel4 ,the intention of the designer in constructing this vessel is to render her so far impregnable1 that in attacking bow on she can defy the opponent's fire1 at the same time offering absolute protection to her commander and steersman1 and also protecting the base of her funnel4 ,the leading feature of the construction of the hull of the ,destroyer is its being provided with an intermediate curved deck1 which extends from stem to stern1 and which is composed of plate iron strongly ribbed1 and perfectly water-tight4 ,this intermediate deck supports a heavy solid armour plate1 fixed transversely to the line of keel1 and #cb feet from the bow1 inclined at an angle of #de1 and supported on its after side by a wood backing #d feet #f inches in thickness4 ,behind this formidable shield the steering wheel is manipulated1 a wire rope extending from its barrel to a four-way cock placed near the stern1 by means of which water pressure is admitted alternately to the hydraulic cylinders1 previously mentioned1 the motion of whose pistons actuate the rudder4 ,the lower division of the vessel is ventilated by powerful blowers1 and contains the machinery2 it also affords a safe retreat for the crew during the attack4 ,the upper division is filled with blocks of cork1 excepting a small part near the bow1 occupied by the aforesaid armour plate and wood backing4 ,the deck house is #gj feet long1 and composed of plate iron1 riveted water-tight to the upper part of the hull4 ,as there are no openings in the sides of this deck house1 the vessel may be run with her upper deck under water4 ,armament of the ,destroyer4--,the ,destroyer is to be armed with torpedoes somewhat similar to the projectile torpedo1 drawings of which were submitted by ,captain ,ericsson1 the inventor1 to ,emperor ,napoleon ,,iii4 in #ahed4 ,the present weapon is composed of a solid block of light wood1 the explosive charge being contained in a metallic vessel inserted at its forward end4 ,instead of being circular1 as was the case with the original torpedo1 its transverse section is square1 with parallel top and bottom and vertical sides1 forming very sharp wedges at both ends1 cased with steel plates4 ,the extreme length of the ,destroyer torpedo is #bc feet4 ,ignition is effected by means of a percussion fuze placed in the head of the weapon4 ,operating the ,torpedo4--,the method of operating the torpedo is that of inserting it into a horizontal tube near the bottom of the vessel1 provided with valves for keeping out the sea during the process of insertion1 as shown at ,fig4 #adh4 ,when near the hostile vessel1 this valve is opened1 and the torpedo expelled by a piston actuated by steam power1 the expulsion being effected without recourse to gunpowder or other explosive agent4 ,the area of the actuating piston of the ,destroyer is #cad square inches1 while the sectional area of the projectile is only #aif square inches2 this difference in size of the two areas is a special and important feature of the invention1 as will be understood from the following3 the tension of the acting medium in the ,destroyer exceeds #bjj lbs4 per square inch1 therefore the torpedo will be pushed out by a force of 7#cad #bjj7 _/ #aif #cbj lbs4 per square inch1 and as the distance passed by the piston while impelling the torpedo is #cj feet1 an energy of nearly #b1jjj1jjj foot-pounds will be imparted to the projectile4 ,when making an attack1 it is intended that the vessel should at the instant of firing her torpedo reverse her engines1 this retrograde motion being greatly assisted by the recoil1 which must attend the discharge of a body weighing some #a1djj lbs4 impelled by the aforesaid enormous force1 and moving through a distance of #cj feet before reaching the water4,o ,certainly this new system of submarine attack seems feasible1 but it has yet to prove1 in common with all other new inventions1 whether its theoretical capabilities are also practical ones4 ,at ,fig4 #adi is shown a general view of this novel torpedo vessel under weigh4 ,illustration3 ,,the ,,destroyer ,,torpedo ,,ship4 ,,plate ,,xlvi ,torpedo ,boats4--,in offensive torpedo warfare1 whether using the spar1 locomotive1 or towing torpedo1 especially in the case of the former class of submarine weapons1 to ensure a successful attack it is absolutely essential to operate those weapons from steam boats1 which are capable of fulfilling as near as possible the conditions herein enumerated3-- #a4--,they should be capable of steaming at least #ah knots per hour4 #b4--,their engines should be noiseless1 and easily managed4 #c4--,they should be extremely handy4 #d4--,no smoke should enable their approach to be detected1 or glare from their fires4 #e4--,that it should be possible to raise steam in them in a few minutes4 #f4--,they should be built in water-tight compartments1 and covered fore and aft to prevent being swamped4 #g4--,the crews should be protected as far as practicable from rifle fire4 ,in addition to the foregoing1 for the purpose of rendering these craft capable of defending themselves against the attack of guard boats1 and also of being employed as such1 and on river expeditions1 c41 they should be built sufficiently strong to enable them to carry a small gun either in the bows or stern2 this would apply more especially to those torpedo boats which are part of a ship's stores4 ,during the last four years a very large number of torpedo boats have been built1 which more or less fulfil the aforesaid conditions1 nearly the whole of which have been constructed by the two ,english firms1 viz4 ,messrs4 ,thornycroft and ,co4 and ,messrs4 ,yarrow and ,co41 and to the latter firm is due the honour of constructing the fastest vessel as yet in the world4 ,up to the present time1 a specially built torpedo boat has on only one occasion been used on active service1 viz4 at the attack on a ,turkish monitor on the #bjth of ,june1 #ahgg1 which is detailed at length in the following chapter4 ,this boat was one of ,messrs4 ,thornycroft and ,co4's launches1 and from all accounts she behaved wonderfully well under the most untoward circumstances4 ,thornycroft ,torpedo ,launches4--,messrs4 ,thornycroft and ,co41 of ,chiswick1 ,london1 have during the last six years built a large number of torpedo launches for the ,english government and for several of the principal ,european governments4 ,norwegian ,launch4--,the first torpedo boat ever built by this firm was the one shown at ,fig4 #aej1 for the ,norwegian government4 ,this boat was #eg feet in length by #g feet #f inches beam1 drew #c feet of water1 and the stipulated speed was #af ,english statute miles1 or nearly #ad knots per hour2 which speed was not to be ascertained by a mere measured mile trial1 but was to be #af miles through the water in a run of one hour's duration4 ,the hull of the vessel was constructed entirely of steel plates and angle bars1 and1 as may be seen from the diagram1 was divided into six water-tight compartments1 ,a1 ,b1 ,c1 ,d1 ,e1 ,f4 ,the compartments marked ,a and ,f in the stem and stern were for stores2 those marked ,b and ,e were fitted with seats for the crew1 and were provided with movable steel covers1 so that on going into action1 or during rough weather1 they might be completely covered4 ,the compartments ,c and ,d are for the steersman and the machinery respectively1 and were covered completely by steel plating #c_/af of an inch in thickness--a thickness sufficient to withstand ,snider or ,martini-,henry bullets1 fired from a distance of twenty paces4 ,the compartment ,d was furnished with a hood1 having slits #a_/d of an inch wide1 all round1 through which the steersman could see with sufficient distinctness to direct his course easily4 ,motion was communicated from the wheel to the tiller by means of steel wire ropes1 which it was originally intended should be encased in wrought iron tubes4 ,the possibility however of these tubes being bent by a shot1 and so jamming the wire ropes1 led to this arrangement being abandoned1 and the ropes were simply run through eyes at intervals along the side4 ,the armament consisted of a cylindro-conical shaped torpedo towed from the top of the funnel1 round which a ring was fitted with two pulleys for the towing rope1 the strain being taken off by means of two stays attached forward4 ,the length of this torpedo was #ac feet and the diameter #i inches1 and with a speed of #aa knots it has diverged to about #dj degrees from the direction of the boat's motion when running in smooth water4 ,the torpedo is worked by means of a small winch and brake fixed on the after part of the engine room skylight2 davits are provided for dropping the torpedo overboard4 ,the engines were compound1 of the usual inverted double cylinder direct acting type1 capable of developing about #ij indicated horse power1 and were fitted with a surface condenser1 so that the vessel could run in salt water1 without danger of injuring her boiler4 ,a small tank contained a supply of fresh water1 to make good deficiencies arising through leakage1 and from steam escaping at the safety valves1 c4 ,the circulating1 air1 and feed pumps were driven by a separate engine4 ,the boiler was of the locomotive type1 the shell being made of ,bessemer steel2 the fire box and its stays of copper1 and the tubes of solid drawn brass4 ,on the official trial1 which took place on the ,thames on the #agth of ,october1 #ahgc1 the number of revolutions done in the hour was found to be #bg1agg1 and the number required to do a mile in still water was #aegh4 ,the distance run in the hour was then1 #bg1agg_/aegh #agbb1 or very nearly #ag-a_/d miles4 ,the steam pressure during the trial averaged #he lbs4 per square inch1 and the vacuum #be-a_/b inches4 ,swedish and ,danish ,boats4--,boats of the same size and similar in all particulars to the foregoing one--excepting the engines1 which are improved by driving the air pump1 feed pump1 and circulating pumps off the main engines1 and abolishing the auxiliary engine1 which performed these duties in the case of the ,norwegian boat--were made for the ,swedish and ,danish governments4 ,the result was an increase of speed to #agbg miles in the case of the ,swedish boat1 and to #ahjf miles1 or #ae-e_/h knots1 in the case of the ,danish boat4 ,there is no information regarding the armament of the ,swedish boat1 but the ,danish boat was armed with two spindle-shaped torpedoes #ab feet long and #aa-a_/b inches diameter1 somewhat like the ,whitehead torpedo4 ,they were placed on deck longitudinally near the funnel1 so as to facilitate launching1 and were arranged to be towed from an upright pole #h feet high1 placed about #f feet from the stem4 ,a small winch was fixed on either side aft1 to pay out the towing line1 and to bring back the torpedo4 ,by these arrangements the torpedo could be projected at a large angle from the direction of the boat's motion1 and at considerable velocity4 ,the speed of the boat when towing one of these torpedoes is about #aj knots4 ,austrian and ,french ,boats4--,the next size of torpedo vessel is that supplied to the ,austrian and ,french governments1 which is shown at ,fig4 #aea4 ,the dimensions are3--length1 #fg feet2 beam1 #h feet #f inches2 draught of water1 #d feet #c inches4 ,the guaranteed speed in the case of the ,austrian boat was #ae knots in a run of one hour's duration1 and in the case of the ,french boats #ah knots1 in a run of two hours' duration4 ,these boats were built of somewhat thicker plating than the #eg feet type1 and the armour was extended4 ,they were divided into six water-tight compartments1 and they differed from the ,scandinavian boats in having the spaces forward and aft of the machinery permanently decked1 instead of being covered with movable steel covers only4 ,the machinery was somewhat similar to that in the ,scandinavian boats1 excepting that the engines were capable of developing #bjj indicated horse power1 and that the air was supplied to the furnace by being forced into an air-tight stoke hole1 instead of being forced directly under the fire grate4 ,the armament of these vessels consisted of two torpedoes attached to the end of wooden poles1 #d-a_/b inches diameter and about #dc feet long1 connected to the battery by insulated wires1 and arranged to be fired either by coming in contact with the enemy's vessel or at any distance from it1 at the will of the operator4 ,the torpedoes themselves were simply copper cases1 of sufficient size1 in the case of the ,austrian boat1 to contain #aa1jjj cubic centimetres of explosive1 and in the case of the ,french boats1 to contain #be kilogrammes of dynamite4 ,the mode of arranging the wires is similar to that explained at page #aee4 ,the method of manipulating the torpedo poles consists of two tubes riveted together at right angles1 so as to form something like the letter ,t4 ,the torpedo pole is put through the horizontal tube1 which is free to move round the centre of the vertical tube1 and the vertical tube is free to move through a quarter circle at right angles to the centre line of the vessel4 ,in attacking in front1 the vertical tube is laid over till it is parallel to the water surface1 and the horizontal tube is allowed to incline sufficiently far to allow of the end of the pole1 when run out1 to be depressed from #h to #aj feet below the water-line4 ,it is held in this position by a pair of blocks attached to the top of a short mast4 ,in attacking on the broadside1 the vertical tube is laid over till it assumes a position such as to allow of the pole1 when swung round1 to touch an enemy's vessel at about #h or #aj feet below the water line4 ,the speed trials of the ,austrian boat took place on the #aath of ,september1 #ahge1 when she did #bd1gjj revolutions on her hour's run on the ,thames1 and the number of revolutions required to do a knot in still water was found to be #aceg4 ,this gives the distance run in the hour as #ahbjb knots1 or #cbjb knots over the contract speed4 ,the steam pressure averaged #aje lbs4 per square inch1 and the vacuum #be-a_/b inches during the run4 ,in the case of the ,french boats1 the total number of revolutions done in the two hours' run in the roadstead off ,cherbourg was #di1hah1 and the number required to do a knot in still water was found to be #achb1 so that the distance run in the two hours was #cfje knots1 or just over the contract speed4 ,during the two hours1 the average steam pressure was #ajh lbs4 per square inch1 and the vacuum #be inches4 ,the ,austrian boat was sent to her destination on board a steamer1 but the ,french boats1 under the command of an experienced captain1 steamed by themselves from ,chiswick to ,cherbourg1 not crossing at the nearest points and running along the shore1 but going boldly from ,dover direct to ,cherbourg4 ,shortly after the arrival of the ,french boats in ,cherbourg1 they were altered so as to attack in front only1 as the ,french authorities found that these small vessels were better adapted for resisting the effects of an explosion at the bow than at any other part4 ,the arrangement adopted is shown at ,fig4 #aeb1 and consisted of a steel pole about #dj feet in length1 having one end about #f inches diameter1 and solid1 and the other about #a-a_/b inches diameter1 and hollow2 this pole was mounted at its solid end on small pulleys1 which ran upon two ropes stretched fore and aft of the vessel2 the other end1 to which the torpedo was attached1 was led over a pulley fixed on the bow4 ,ropes passing over pulleys to a windlass in the after compartment were attached to the inboard end1 and by turning the windlass the pole was drawn backwards or forwards as required4 ,it will be observed that as the pole is drawn forward1 the inboard end being constrained to move in a line parallel to the deck1 the outer end is depressed in the water1 and is so adjusted that when the pole is run out to its full extremity1 the torpedo is depressed to about #h-a_/b feet below the water level4 ,dutch and ,italian ,boats4--,the third size of boat built by this firm for the ,dutch and ,italian governments are #gf feet long and #aj feet beam1 and are guaranteed to do a speed of #ah knots4 ,these boats are similar in design to the ,austrian and ,french boats previously described1 but differ from them in having engines of #bej indicated horse power1 and in having more free board forward1 so as to make them better sea boats4 ,the ,dutch type are armed with the outrigger torpedo1 as fitted to the ,french boats1 and the ,italian type with the ,whitehead fish torpedo4 ,the ,lightning ,type of ,boat4--,now comes the ,lightning type of vessel1 which is shown at ,fig4 #aec4 ,this vessel1 built for the ,english government1 is #hd feet long over all1 #aj feet #aj inches beam1 and draws about #e feet of water4 ,the machinery on board the ,lightning is similar in design to that already described1 and is capable of indicating #cej horse power4 ,the hull of the ,lightning is made of heavier plating than usually employed1 and her lines are fuller1 as she is intended for use in a tolerably rough sea if necessary2 and in order that she may be able to remain at sea for some time1 cabin accommodation on a scale larger than in any of the other boats is provided for the officers and crew4 ,the steering gear is arranged so that the vessel may be steered from the deck1 or from the conning tower1 and the usual telegraph gear is fitted to communicate from the deck1 or from the conning tower1 to the engine room4 ,the top of the conning tower is supported on three screws1 so arranged that it may be raised or lowered1 and the space for sight adjusted according to the range of vision required1 or the risk to be run from the enemy's missiles4 ,the ,lightning is armed with fish torpedoes1 which are discharged from her deck forward by means of a discharging apparatus4 ,the torpedoes are charged with air1 by means of one of ,mr4 ,brotherhood's air-compressing pumps4 ,the ,lightning on her preliminary runs attained a speed on the measured mile of #aid knots per hour1 a speed which will be somewhat reduced when she has her torpedoes1 c41 on board1 but which will then be over #ah knots per hour4 ,several torpedo boats have been built and are in process of construction by this firm for the ,english government4 ,illustration3 ,,thornycroft',s ,,torpedo ,,boats4 ,,plate ,,xlvii ,french ,boats4--,the next size of boats is the #hg feet type1 as shown at ,fig4 #aed4 ,of this type of torpedo launch several have been built and are now under construction for the ,french government4 ,these vessels are #aj feet #f inches beam2 draught of water about #e feet4 ,they are built of heavier plating than the ,lightning1 and are guaranteed to maintain a speed of #ah knots4 ,the propellers in these boats are placed in front of the rudder1 so as to give increased readiness in steering4 ,in order to prevent oxidation as far as possible1 the plates and frames below the water line are galvanised4 ,a spark-catching apparatus is fitted to the base of the funnel1 so as to prevent the position of the boat being betrayed to the enemy at night4 ,the armament of these vessels consist of an outrigger arrangement similar to that described at page #afg4 ,they are also well adapted for the ,whitehead torpedo4 ,they are also provided with a strong buffer in the bows for deadening the shock1 in the event of their coming into contact with an enemy's vessel at too high a rate of speed4 ,second ,class ,boats and ,mode of ,manipulating the ,fish ,torpedoes from them4--,another type of ,thornycroft torpedo boats1 several of which have been built for continental governments1 and which is termed ,second class1 is shown at ,fig4 #aee4 ,these boats are #fj feet long1 #g feet #f inches beam1 and draw some #c feet of water2 their guaranteed speed being #af knots per hour4 ,the mode of carrying the ,whitehead fish torpedo1 and manipulating it from such a boat by means of ,mr4 ,j4 ,i4 ,thornycroft's invention1 which has been fully described at page #adj1 is shown at ,figs4 #aee and #aef1 where ,fig4 #aee represents both torpedoes housed1 and ,fig4 #aef one torpedo in the firing position1 the other one being housed4 ,four of this type of ,thornycroft torpedo boats were attached to ,h4,m4,s4 ,hecla during her recent cruise in the ,mediterranean1 and have been very favourably reported on as follows3--,they do not suffer from the blows of the sea1 nor from the strains incident upon hoisting in and out2 nor yet when they are suspended ready for lowering1 in which latter position they have frequently remained for twenty-four hours2 that under careful management they are perfectly safe in a heavy sea1 and they possess good manoeuvring powers4 ,the ,thornycroft torpedo frames were found to perform well the services for which they are intended4 ,when proceeding at ordinary speed they are nearly noiseless1 and cannot be seen on a dark night at a distance of #ajj yards4 ,the ,thornycroft ,propeller4--,all the torpedo boats built by this firm are fitted with the propeller invented by ,mr4 ,thornycroft1 and which bears his name4 ,it is a modification of what is known as the ,dundonald propeller1 the principal difference being that in the ,dundonald propeller the blades are inclined backward in straight lines1 while in the ,thornycroft propeller they are curved4 ,experiment at ,cherbourg4--,the following account of an experiment which took place at ,cherbourg in ,march #ahgg1 whereby to test the efficiency of a ,thornycroft torpedo boat in exploding a spar torpedo under the bottom of a vessel proceeding ahead at the time1 is taken from the ,times1 under date the #acth of ,march1 #ahgg4 ,illustration3 ,,thornycroft',s ,,torpedo ,,boats4 ,,plate ,,xlviii ,admiral ,jaurez1 who commands the squadron1 ordered a disabled ship1 the ,bayonnaise1 during a rather rough sea1 to be towed out by a steamer belonging to the navy4 ,a second lieutenant1 ,m4 ,lemoinne1 was sent for1 and informed that he had been selected to make the experiment of launching the ,thornycroft against the ,bayonnaise while both were in full sail4 ,he accepted the mission without hesitation1 picked out two engine men and a pilot1 and went down with them into the interior of the ,thornycroft1 of which only a small part was above water2 this visible portion being painted of a greyish colour1 so as to be easily confused with the sea4 ,the torpedo was placed so as to project from the bow of the vessel1 at the extremity of which were two lateen sailyards about three metres in length4 ,the towing steamer then took up its position in front of the squadron1 and the ,thornycroft also assumed the position assigned for it2 an interval of three or four marine miles separating the torpedo boat and the ,bayonnaise4 ,on a signal being given1 both were set in motion1 the steamer advancing in a straight line1 and the ,thornycroft obliquely1 so as to take the ,bayonnaise in flank4 ,the steam tug went at #ad knots an hour1 going at full speed in order to escape the ,thornycroft4 ,the latter went at #ai knots an hour1 a rate not attained by any vessel in the squadron4 ,the chase lasted about an hour1 the squadron keeping in the rear1 so as to witness the operations4 ,at the end of that time the distance between the ,thornycroft and the ,bayonnaise had sensibly diminished1 and at a given moment the former1 in order to come up with the latter at the requisite distance1 had to slacken speed to #h knots an hour4 ,the whole squadron watched this last phase of the struggle with breathless interest1 and people asked themselves whether the shock of the torpedo would not infallibly destroy the little vessel which bore it4 ,it was feared that the lives of the second lieutenant1 ,lemoinne1 and his three companions were absolutely sacrificed4 ,however1 the two vessels got visibly nearer4 ,all at once the ,thornycroft put on a last spurt1 and struck the ,bayonnaise with its whole force on the starboard bow4 ,the sea was terribly agitated1 a deafening report was heard1 and the ,bayonnaise1 with a rent as big as a house1 sank with wonderful rapidity4 ,as for the ,thornycroft1 rebounding by the shock about fifteen metres off1 even before the explosion occurred1 it went round and round for a few moments1 and quietly resumed the direction of the squadron4 ,no trace remained of the ,bayonnaise2 it was literally swallowed up by the sea4 ,the experiment was a most complete success1 the torpedo boat not being in the least degree injured4 ,the ,power of ,flotation of a ,thornycroft ,boat after being pierced by a ,rifle ,shot4--,on the #eth of ,july1 #ahgg1 ,messrs4 ,thornycroft and ,co4 made an experiment with one of their torpedo boats to ascertain under what conditions flotation is still retained after the boat has been pierced by a rifle shot4 ,the torpedo boat experimented on was similar to the one which has been described at page #afi4 ,a ,martini-,henry was fired through her side1 about a foot under water in the stoke hole4 ,whilst at anchor the water entered in sufficient quantity to fill an ordinary size bucket in twenty-five seconds1 but when she was driven ahead less water entered1 and on the speed of #aj knots being reached1 little or no water entered4 ,the hole was a little more than three quarters of an inch in diameter4 ,the engagement on the ,danube between the torpedo boat ,schootka and some ,turkish vessels1 in which the former vessel was pierced by bullets1 but yet did not sink1 led to the above experiment being carried out4 ,efficiency of ,thornycroft's ,engines4--,as a practical proof of the efficiency of the engines supplied by ,messrs4 ,thornycroft and ,co4 to their torpedo boats1 a similar engine has been used for over two years to work the various machines in connection with their works at ,chiswick4 ,torpedo ,boats built by ,messrs4 ,yarrow and ,co4--,messrs4 ,yarrow and ,co41 of the ,isle of ,dogs1 ,london1 are also very well-known torpedo boat builders1 and have during the last four years constructed a considerable number of such vessels for the ,english and different continental governments1 and1 as has been before stated1 they are the constructors of the fastest vessel in the world4 ,dutch ,torpedo ,launch4--,in #ahge this firm built a torpedo launch for the ,dutch government1 specially designed for ocean purposes4 ,it was #ff feet long1 #aj feet beam1 and #e-a_/b feet deep4 ,she was driven by a pair of inverted direct acting engines4 ,the boiler was of the locomotive type1 with a working pressure of #adj lbs4 per square inch1 and capable of exerting a force of some #bjj indicated horses4 ,russian ,torpedo ,boat4--,this firm also constructed for the ,russian government two torpedo steamers #he feet in length4 ,the guaranteed speed of these vessels being #bj knots per hour4 ,in #ahgh the ,russian government ordered one hundred exactly similar boats to be constructed1 mostly at ,st4 ,petersburg1 thus proving the high estimation held by that government of ,messrs4 ,yarrow and ,co4's torpedo boats4 ,description of a ,yarrow ,torpedo ,launch4--,figs4 #aeg1 #aeh1 and #aei show an elevation1 section1 and plan of a torpedo boat1 ,yarrow type1 a large number of which have been built for the ,russian and other continental governments4 ,the length of this boat is #ge feet1 its beam #aj feet1 and draught of water #c feet4 ,she is built of steel of the best quality1 no other metal possessing the requisite strength and stiffness for scantling1 and plates of such lightness4 ,it is divided into eight compartments by seven transverse bulkheads1 the forward and after compartments being used for stores1 the two central ones enclosing the machinery1 while the steersman and operator are placed in the compartment immediately abaft the engines4 ,the steersman's head projects above the deck1 and is protected by a rifle proof steel truncated cone1 the top part of which is movable like the visor of a helmet4 ,the hull is decked over from end to end with a curved shield1 the midship plating of which is capable of resisting rifle shots1 even at close quarters2 its curved form being well adapted for giving the maximum strength to the structure1 and quickly frees itself from any large body of water4 ,illustration3 ,,yarrow',s ,,torpedo ,,boats4 ,,plate ,,xlix ,the propelling machinery consists of a pair of inverted compound condensing engines4 ,the revolutions per minute at full speed are about #dgj1 and the indicated horse power about #bhj4 ,the propeller is of steel4 ,the funnel is fixed at one side of the centre line1 to be out of the way of the bow torpedo pole and gear4 ,this type of torpedo boat attains a speed of from #ag-a_/b to #ah-a_/b knots per hour4 ,the armament of some of these boats consists of three spar torpedoes1 a bow1 and two quarter ones4 ,the bow pole1 which is strong and heavy1 is hauled out and in by means of a small auxiliary engine4 ,boats similar to these1 but of larger dimensions1 viz4 #hd feet long and #aa feet beam1 have also been constructed by this firm4 ,speed from #ai to #bj knots per hour4 ,english ,torpedo ,boats4--,the following account of two torpedo boats which had been originally built by this firm for the ,russian government1 but1 owing to the proclamation issued by the ,english government at this time prohibiting torpedo boats leaving ,england1 were seized by the ,customs authorities when on the point of completion1 and were ultimately purchased by the ,english government1 is an extract from the ,times under date the #dth of ,july1 #ahgh4 ,these vessels are each #he feet long with #aa feet beam1 and draw1 when fully equipped for service1 an average of #c feet of water4 ,they are strongly constructed of steel1 and are fitted with compound surface condensing engines capable of indicating #dbj horse power4 ,the high pressure steam cylinder of these engines is #ab-a_/b inches in diameter1 and the low pressure #ba-a_/b inches1 both having a #ab inch stroke4 ,these boats are at present known by their builders' numbers1 one being ,no4 #dai and the other ,no4 #dbj4 ,the former is propelled by a three-bladed screw1 #e feet #f inches diameter and #e feet pitch2 and the latter by a two-bladed screw of similar proportions4 ,messrs4 ,yarrow adopt supplementary engines for driving the air pump1 circulating pump1 and feed pumps2 they consider this plan preferable to that of working these pumps direct off the main engine1 as is sometimes done4 ,one advantage in having separate pumping engines is that1 whether the vessel is in motion or stationary1 a powerful means is available for pumping her out1 should the necessity arise4 ,it is estimated by her builders that if the air pump and circulating pump were both utilised for this purpose1 the water could be pumped out as fast as it could enter either of these vessels through one hundred holes made in the skin by ,martini-,henry rifle bullets4 ,if this is the case1 these craft may be deemed safe from sinking so long as their machinery is working efficiently4 ,the boiler is of the locomotive type1 placed in the forward part of each vessel1 and has a closed stoke hole4 ,in connection with the boiler a very important improvement has been introduced by ,messrs4 ,yarrow4 ,this consists in a means of rendering the closed stoke hole safe for the men in the event of the collapse of a boiler tube--a contingency which cannot be absolutely guarded against4 ,its efficiency was proved beyond all question upon a previous trial of one of these boats4 ,this was ,no4 #dai1 which was tried on the #bdth of ,may last under the supervision of the ,admiralty officials4 ,upon that occasion an accidental rupture of one of the boiler tubes occurred nearly at the close of the runs over the measured mile1 which so far had been very successful4 ,when the boiler tube gave way the steam rushed out of the foremost hatchway from the compartment in which the smoke box end of the boiler is situated1 and soon after from the two funnels4 ,the men in the stoke hole1 however1 being shut off from the boiler1 were uninjured1 and remained at their post several minutes after the first outburst of steam4 ,the accident1 although an untoward event1 was considered by the ,admiralty officials as affording a highly satisfactory proof of the efficiency of ,mr4 ,yarrow's invention4 ,the engines are placed amidships1 and each vessel has spacious cabin accommodation aft1 as it is intended that they may be used either as despatch or torpedo boats4 ,for the latter purpose the cabin framings above deck are removed and replaced by steel plating4 ,they are steered from the cabin1 there being a look-out for the steersman just above deck level4 ,the deck is clear of all obstructions1 the two funnels being placed one on either side4 ,they are fitted with balanced rudders and steer well1 answering their helms very quickly4 ,the trials of these two torpedo boats are taken from the ,engineer under date the #aith of ,july1 #ahgh4 ,at that time these boats completely eclipsed in speed everything that had hitherto been done4 ,at ,fig4 #afj is shown in elevation this type of torpedo launch4 ,the trials were personally conducted by ,mr4 ,yarrow1 under the superintendence of the authorities from ,whitehall1 and consisted in a two hours' run without stopping1 during which time the boats were tested at the measured mile at ,long ,reach4 ,each boat was run six times over the mile1 three runs with the tide and three runs against it4 ,the boats and machinery are similar in every respect1 excepting that ,no4 #dai is fitted with a three-bladed propeller1 and ,no4 #dbj a two-bladed one1 their diameters and pitch being the same in both cases4 ,the weights on board were accurately weighed1 and amounted to #f tons in each boat1 including coals1 water1 crew1 and ballast4 ,trial of ,no4 #dai4 ,min4 ,sec4 ,knots per hour4 #ast run down occupied #b #cf #bcjgf #ast run up #c #bj #ahjjj #bnd run down #b #ce #bcbbf #bnd run up #c #af #ahcfg #crd run down #b #cb #bcfhd #crd run up #c #ad #aheeg ,mean of the six runs1 #bjhah knots per hour4 ,mean steam pressure1 #aae lbs4 per square inch4 ,vacuum1 #bc-a_/b inches4 ,mean revolutions of main engines per minute1 #def4 ,trial of ,no4 #dbj4 ,min4 ,sec4 ,knots per hour4 #ast run down occupied #b #cc-a_/b #bcdeb #ast run up #c #be-a_/b #ageah #bnd run down #b #cb-a_/b #bcfjf #bnd run up #c #ba #agiaj #crd run down #b #cb #bcfhd #crd run up #c #bd #agfdg ,mean of the six runs1 #bjfcf knots per hour4 ,mean steam pressure1 #aae lbs4 per square inch4 ,vacuum1 #bd inches4 ,mean revolutions per minute1 #dff4 ,the highest speeds were obtained by ,no4 #dai1 during the third runs up and down1 the mean of which give #baab knots1 which is equal to #bd-a_/c statute miles per hour1 during which time the engines were making #dgj revolutions per minute4 ,at the close of the runs1 the bearings were found to be in first-class condition1 and there was not the least sign of anything getting warm during any part of the trials4 ,spanish ,torpedo ,boat4--,the following description of a torpedo boat built by this firm for the ,spanish government1 enumerating all the improvements that have of late been effected in the construction of such vessels by members of this firm1 is taken from the ,engineering under date the #bast of ,february1 #ahgi4 ,the alterations have a twofold character1 and have reference to the arrangements for discharging the products of combustion from the furnaces and to those for steering the vessel4 ,in brief1 the boat is funnelless and is fitted with two rudders1 one at each end4 ,the main object in dispensing with the funnel is to enable the torpedo boat to approach as closely as possible to an enemy without being seen1 a secondary1 although still an important1 consideration1 being the absence of any obstruction to the steersman's view1 such as a funnel on deck4 ,the outlets for the smoke in the present instance are two ports1 one on either side of the vessel1 and placed about #ae feet in from the bow4 ,each of these smoke ports is fitted with a damper1 and the smoke can be turned through either or both of the passages as desired4 ,the control of these dampers is given to the steersman1 who1 on approaching an enemy1 can direct the products of combustion through the port on the unexposed side of the vessel4 ,the emission of smoke by day and of the glare and sparks by night are thus to a very large extent hidden from view1 thus enabling the torpedo boat to approach very closely to the point of attack without being observed4 ,the outlets are fitted with valves which are kept open by the blast1 but which close on being struck by a passing wave4 ,should the vessel have to be out when a heavy sea is running the ports are closed1 and a spare funnel is rigged up on deck1 on one side4 ,although the smoke ports are placed forward in this boat1 it is intended to place them aft in the next that ,messrs4 ,yarrow build1 as that arrangement will obviate the inconvenience at present experienced by those on deck from the heated gases of the furnace being carried along it at times by the wind1 when on a certain course4 ,illustration3 ,,yarrow',s ,,torpedo ,,boats4 ,,plate ,l ,the steering powers of the boat have next had attention from ,messrs4 ,yarrow1 and they have sought to remedy the defective steering common to these large quick-speed torpedo craft4 ,to do this they have fitted the vessel under notice with two balanced rudders1 one of which is placed forward about #aj feet from the bow1 and the other in its usual position at the stern with the screw abaft it4 ,both rudders are connected with the same steering gear1 and are operated simultaneously by one steersman4 ,the forward rudder can be raised out of the water into a casing inside the boat if desired by means of a screw cut on the upper part of its spindle4 ,by the same means1 by unscrewing the collar on the spindle1 the rudder can be released and dropped into the water should the necessity arise for so doing1 by reason of its becoming fouled or damaged4 ,in trials which have been made with this double-steering system1 it has been found that when steaming at high speeds the forward rudder has a much greater control over the motion of the boat than the stern one4 ,the reason assigned for this is that at high speeds the forward part of the boat is lifted out of the water1 and consequently offers a diminished side resistance to any turning motion brought to bear upon it4 ,the boat in which these improvements have been introduced is #hf feet long by #aa feet beam and #e feet #f inches deep4 ,she is fitted with compound engines having #bb inch and #ab-a_/b inch cylinders1 with a #ab inch stroke1 and making #ebj revolutions per minute when running at full speed4 ,she is propelled by a three-bladed screw #e feet #f inches in diameter and #e feet pitch4 ,put through some evolutions with the view of testing her steering powers1 the double rudder arrangement was found to answer exceedingly well1 and she turned a circle of a diameter equal to about three times her own length in #a minute #ae seconds4 ,she turned equally well either going ahead or astern1 and in fact her steering capabilities were satisfactorily demonstrated4 ,the new arrangement for carrying off the smoke also answered very well1 with the exception that the heated gases occasionally swept the deck1 which objectionable result will be avoided in future boats4 ,these boats are to be armed with spar torpedoes1 and with the ,whitehead fish torpedo1 the cradles and fittings for which are shown at ,fig4 #afa4 ,the ,fastest ,vessel in the ,world4--,another type of torpedo boat1 of which one of the same dimensions has been built by this firm for the ,english government1 is shown at ,fig4 #afb4 ,this vessel is as yet the fastest vessel in the world4 ,the trials with this boat were made in ,march of this year1 and were as follows3-- ,runs4 ,time1 ,knots ,knots ,min4 sec4 per hour4 per hour4 ,first #b #cg #bbic ,second #c #b #aigh ,mean of first pair #bace ,third #b #cc #bcec ,fourth #b #ee #bjeg ,mean of second pair #bbje ,fifth #b #cj #bdjj ,sixth #b #ef #bjde ,mean of third pair #bbbc giving as a mean #baic knots per hour1 or #be-a_/d statute miles4 ,the boat was fully equipped for active service1 i4e4 with a load of #f-c_/d tons on board4 ,it was found during the trial that at speeds of #ag and #ai knots the vibration of the boat was considerable1 but when running over #bj knots it was hardly perceptible2 the excessive vibration taking place when the revolutions of the engines became a multiple of the natural vibration of the boat4 ,torpedo boats are at the present time being built by this firm for the ,english1 ,french1 ,spanish1 ,austrian1 and ,italian governments4 ,russian ,torpedo ,boats1 built by ,mr4 ,s4 ,schibau1 ,prussia4--,mr4 ,s4 ,schibau1 of ,elbing1 ,eastern ,prussia1 in #ahgh constructed ten torpedo boats for the ,russian government1 similar to the one shown at ,fig #afc4 ,these boats are each #ff feet long1 and #aa feet #c inches beam4 ,they are built of steel plates about an eighth of an inch thick4 ,their engines consist of three cylinder compounds1 with surface condensers2 and they run at #chj revolutions per minute1 at full speed1 driving a screw #d feet in diameter4 ,they have been variously armed1 some with the spar1 some with the ,whitehead fish1 and some with the ,harvey towing torpedo4 ,their speed is about #ah knots per hour4 ,messrs4 ,herreshoff's ,torpedo4--,messrs4 ,herreshoff1 of ,rhode ,island1 ,u4,s4,a41 have also constructed several torpedo boats4 ,one of these1 built for the ,english government1 is shown in section at ,fig4 #afd4 ,this boat is #ei feet #f inches long1 #g feet #f inches beam1 and #e feet #f inches deep2 she draws about #a foot #c inches of water4 ,illustration3 ,,russian ,,torpedo ,,boat1 ,,herreshoff',s ,,torpedo ,,boat4 ,,plate ,,li ,the vessel is constructed with five water-tight bulkheads1 and her hull is of composite construction below the water line1 having a steel framing covered with wood planking4 ,the upper part of the hull is wholly of steel1 the plates being #a_/af inch thick1 the top sides sloping inwards and the upper work forming a protective superstructure for the crew and machinery4 ,she is propelled by a screw which is placed beneath the vessel in a central position1 and which is driven by a direct acting condensing engine placed in the forward part of the boat4 ,the diameters of the steam cylinders are #aj-a_/b inches and #f inches respectively1 with #aj inch stroke1 and they are of #ajj horse power estimated4 ,there is an independent feed pump and air pump4 ,the stoke hold is enclosed and is supplied with air by a ,sturtevant blower1 which is driven by an independent engine of #b-a_/b horse power4 ,the propeller is a two-bladed screw #ch inches in diameter and #e feet pitch1 the screw shaft being #bc feet in length4 ,the vessel is steered by means of a balanced rudder placed a short distance from the stern and under the ship1 the helmsman being located in a stern cabin with a protected look-out raised just above the deck4 ,the hull and machinery together weigh #f tons1 but with the working crew of four men and fuel1 stores1 and two torpedoes on board1 boat weighs about #g-a_/b tons4 ,steam is supplied by a ,herreshoff coil boiler1 which constitutes another novelty in this boat4 ,this boiler consists of a circular combustion chamber1 which in the present instance is #d feet in diameter internally1 and within which is a coil of about #cjj feet of #b inch pipe coiled to nearly the diameter of the chamber4 ,this coil is continued at the top so as to form a kind of dome under the cover of the combustion chamber4 ,by the side of the boiler is a separator1 into which the steam passes before it goes to the engine4 ,the water from the feed pump is admitted at the top of the coil1 and during its course to the bottom the greater portion of it becomes converted into steam4 ,having passed through the entire length of the coil1 the steam and water are discharged together into the separator in such a manner that the water is entirely separated from the steam1 and can be blown off as required4 ,the steam is taken from the top of the separator1 and returns through a short coil placed inside the combustion chamber1 where it becomes superheated1 and is led thence to the engines4 ,it is claimed for this boiler that it cannot explode destructively1 inasmuch as there is but a very small quantity of water in it at any time1 and that it is distributed along the entire length of the coil4 ,a rupture at any point would only be attended by a moderate blowing off of steam4 ,the rapid circulation of the water is found to prevent the deposit of salts1 the surplus water not converted into steam carrying with it all impurities4 ,a good working pressure can be obtained within a few minutes of lighting the fire1 and the boiler can be blown off in a few seconds4 ,the large combustion chamber enables the full economy of the fuel to be realised4,p ,this vessel is guaranteed for a speed of #af knots per hour4 ,she can be propelled ahead or astern with equal speed1 and can be brought to a dead stop when going full speed within a distance equal to her own length4 ,her turning powers are equally good4 ,her armament will probably be the fish torpedo4 ,ordinary ,torpedo ,boat4--,the most efficient and simple method of fitting and working a spar torpedo from an ordinary steam launch or pinnace is shown at ,fig4 #afe4 ,this method will be readily understood from the figure2 the dotted lines show the position of the spar and upright1 when rigged in4 ,the speed of this type of torpedo boat ranges from #f to #i knots4 ,occasions would no doubt occur in time of war when a torpedo attack by such boats would be a feasible matter1 and therefore everything should be done to render these boats fit for that special service4 ,defects4--,the most important defects of such craft are3-- #a4--,the noise created by their engines1 thus rendering an undetected approach to a hostile vessel impracticable4 #b4--,their liability to be swamped by the explosion of the torpedo4 ,of course there are many minor defects1 but above are the principal ones1 both of which might1 to a considerable extent1 be modified4 ,torpedo ,boat ,attacks4--,it is impossible to attempt more than a very general idea of how to conduct a torpedo boat attack1 as so much depends upon the circumstances1 ever changing1 under which each particular attack would have to operate4 ,the spar and the fish torpedo are the submarine weapons that can best be manipulated from boats1 the towing torpedo requiring a more roomy craft than the torpedo boat generally is to operate it from with any chance of success4 ,methods of ,protecting ,ships from ,boat ,torpedo ,attacks4--,the principal methods that exist at the present time of protecting a ship from a boat torpedo attack are as follows3-- #a4--;,booms by themselves1 or supporting nets hung vertically1 surrounding the ship at a distance of #aj or #ae feet from the side of the vessel4 #b4--;,a crinoline of wire1 or chain1 fixed by stays to the vessel's side1 but capable of being lifted out of the water if required4 #c4--,the above methods supplemented by guard boats1 and a cordon of boats4 #d4--;,a cordon of boats1 that is1 boats connected at certain distances by means of hawsers1 or chain cables1 and at a distance of some #bjj or #cjj yards from the vessel1 supplemented by guard boats1 but without other protection4 #e4--;,electric lights and torpedo guns4 ,these latter are small guns capable of penetrating the side of a torpedo boat and of being depressed at a very small angle4 ,as it is against these defences that torpedo boats would have to contend1 therefore they have been described previous to explaining the mode of conducting a torpedo boat attack4 ,the first two methods of defence are of course quite impracticable when the attacked vessel is one of a blockading squadron1 and it is against such vessels that a torpedo boat attack will generally be used and oftenest be successful4 ,in the case of a vessel forced to anchor in a harbour which is accessible to the torpedo boats of the enemy1 by the application of either of the first two methods1 supplemented by guard boats and electric lights1 she would undoubtedly be almost impregnable against a torpedo boat attack1 even were the boats armed with the fish torpedo1 though she would of course not be in that state of readiness which is essential to a man-of-war's efficiency4 ,as a general rule1 no man-of-war should anchor unless absolutely necessary in the vicinity of an enemy's ports1 and then should retain the power of moving in any direction in the quickest space of time possible1 using the electric light and guard boats as a means of protection4 ,an attack by boats armed with the spar torpedo must always partake of the nature of a forlorn hope1 this especially applying to the boats themselves1 the crews of which1 provided they are supplied with good life belts1 would seem to run a far greater risk of a wetting and a prison than of being shot4 ,not less than four torpedo boats should compose the attacking force4 ,the crews of the boats1 consisting of only those actually required1 should fully understand that the hostile vessel is to be torpedoed1 i4e4 they are not to give up the attack on the vessel opening fire1 nor in the case of one or more of the torpedo boats being sunk1 but to remember that one boat is sufficient to effectually carry out the object of the attack1 viz4 the sinking of the ship4 ,in making the attack1 one boat should be directed on each bow1 and one on each quarter1 the final rush being as combined as possible4 ,there must not be the slightest hesitation1 and each boat must make direct for her point of attack4 ,the cause of the ,russians failing so often in their torpedo boat attacks during the war of '#gg may be traced to the absence of anything like a system1 and to their giving up the attack directly they supposed themselves discovered4 ,when using the towing torpedo1 two boats only could be used1 and they should make the attack1 either coming down from ahead1 one on each side of the vessel1 or coming up from the stern1 one on each side of the vessel1 or by the boats crossing the bow and stern of the vessel in different directions4 ,in the case of the fish torpedo the attack must be conducted in a different manner1 the object in this case being to get within a certain distance only of the vessel undetected1 and from thence send the missile on its deadly course4 ,the distance should not be more than #ejj yards2 the closer up to #bjj yards the better4 ,in connection with such an attack1 the torpedo boats might be supported by guard boats1 whose particular duty it would be to engage the enemy's guard boats and so leave the torpedo boats free to do their particular work4 ,it has been suggested to use the electric light from the bows of torpedo boats1 but this would do away with one of the chief characteristics of such boats1 viz4 their invisible and unknown approach1 on which the whole success of the attack in a great measure depends4 ,fosberry's ,patent ,torpedo ,boat ,protective4--,to enable torpedo vessels and boats to remain afloat after being struck by shot from mitrailleuses1 rifles1 and other arms usually employed against such craft1 and at the same time to retain their structural lightness1 ,colonel ,g4 ,v4 ,fosberry1 of the ,english army1 has designed the following method1 which is based upon the discovery that when india-rubber or the like is placed and secured on a metal plate1 and is penetrated or punctured by a rifle bullet or similar projectile1 which also passes through the metal plate1 the hole or orifice so formed in the india-rubber will1 after the projectile has passed through it and the metal plate1 immediately be closed by the elasticity of the surrounding portions1 so that no water can follow the projectile through the said hole or orifice4 ,india-rubber or other elastic material1 or a combination of such materials1 in the form of sheets1 belts1 or coats1 is placed upon or around those portions of the hull of the boat which are to be protected4 ,vulcanised or mineralised india-rubber is the material usually employed by ,colonel ,fosberry4 ,between the metal plates and the india-rubber covering an intermediate substance1 generally kamptulicon1 is interposed1 which is cemented or riveted to the said metal plates1 and to which the india-rubber is attached4 ,this intermediate substance1 which is the feature of the invention1 must be of such a nature that it may be caused to adhere closely and tightly to all parts of the metal1 and also to the india-rubber covering1 while the same are unperforated1 but when the said india-rubber covering and the metal plate under the same are perforated by a bullet1 the portion of the said intermediate substance adjacent to the perforation must be detached from the elastic covering and metal plate1 and leave the former free to act like a valve1 and close up over the hole so that no water may enter2 and this intermediate substance1 as applied by the inventor in the immediate vicinity of the perforation1 will by the effect of the shot be so broken up and detached from the india-rubber covering as to allow the same to recover its original position independently of the new shape or position of the injured and deformed metal plate4 ,should the india-rubber be placed upon the metal plates and be so attached to the said plates as to adhere and conform to them in or after their deformation1 a hole made in the india-rubber would remain open2 on the other hand1 should the india-rubber without any intermediate substance be attached to the metal plate in such a manner that it will recover its position after perforation1 water would penetrate between the metal and the india-rubber1 and by the pressure of this water the india-rubber would be liable to be detached from a large area of the metal plate1 and so become ineffective or even dangerous to the boat4 ,moreover1 if the india-rubber is fixed directly upon the metal plates1 in the case of a shot passing completely through the boat1 that is to say1 passing into the boat at one side and out at the other side1 a large portion of the india-rubber adjacent to the hole made by the shot in leaving the boat will be torn or destroyed1 but this will not be the case in boats constructed according to ,colonel ,fosberry's patent4 ,the ,french government have recently applied this invention to one of their torpedo boats with very successful results1 thereby proving that it is not merely a theoretical idea4 ,submarine ,boats4--,submarine boats1 if they could be constructed to fulfil the conditions hereinafter enumerated which are essential to a perfect boat of that nature1 would for many reasons be a very important point solved in connection with torpedo operations1 and therefore it is most extraordinary that a practicable submarine boat has not yet been designed and built4 ,bushnell's ,submarine ,boat4--,the first submarine vessel built for torpedo purposes was designed and constructed by ,david ,bushnell in #agge4 ,this vessel1 operated by a ,sergeant ,esra ,lee1 was employed in an attempt in #aggf or thereabouts on the ,eagle1 an ,english man-of-war1 which proved unsuccessful1 owing to the sergeant not being thoroughly versed in the management of his curious craft4 ,she was soon afterwards sunk in the ,hudson river1 but was subsequently recovered by the inventor1 though never used again4 ,this vessel was capable of holding one person1 and air sufficient to support him thirty minutes without receiving fresh air1 and is fully described in ',barnes's ,submarine ,warfare4' ,qualifications essential to a ,submarine ,boat4--,a submarine boat should possess the following qualifications3-- #a4--;,it should be of sufficient displacement to carry the machinery necessary for propulsion1 and the men and materials for performing the various operations4 #b4--;,it should be of such a form that it may be easily propelled and steered4 #c4--;,it should have sufficient interior space for the crew to work in4 #d4--;,it should be capable of carrying sufficient pure air to support its crew for a specified time1 or of having the means of purifying the air within the boat1 and exhausting the foul air4 #e4--;,it should be able to rise and sink at will to the required depth1 either when stationary or in motion4 #f4--;,it should be so fitted that the crew possess the means of leaving the boat without requiring external assistance4 #g4--;,it should carry a light sufficient to steer by1 and to carry on the various operations4 #h4--;,it should possess sufficient strength to prevent any chance of its collapsing at the greatest depth to which it may be required to manipulate it4 ,the results of former experiments with such boats prove that manual power1 which was the original mode of propulsion1 is not the motive power best adapted to such a boat2 compressed air1 gas as used in the ,lay torpedo boat1 and steam1 are all of them far preferable to the original method1 but which of these modern ones is the most practicable has yet to be decided4 ,the most difficult point to be overcome in connection with a submarine boat is that of steering it correctly when beneath the surface of the water4 ,confederate ,submarine ,boat4--,the ,confederate submarine torpedo boat that sunk the ,federal vessel of war ,housatonic on the #agth of ,february1 #ahfd1 was built of boiler iron1 #ce' long1 #c' beam 7extreme71 #e' high in the centre4 ,she carried a crew of nine men4 ,she was propelled by means of a screw propeller worked by eight of the crew1 her greatest speed being four knots an hour in smooth water4 ,she carried a sufficient quantity of air to enable the crew to remain submerged for the space of two to three hours4 ,two fins were fitted on the outside for rising and falling at will1 when in motion4 ,there were two manholes provided1 fitted with bull's-eyes4 ,this boat was intended to pass under a vessel's bottom1 towing a torpedo after her1 which was arranged to explode on contact4 ,she was the means of drowning fourteen men before she made her last attempt1 when nine others were added to the above list4 ,in her successful attack on the ,housatonic1 she was armed with the bow spar torpedo1 and was sunk1 owing to her running into the hole formed by the explosion of her torpedo4 ,about three years after the ,american civil war was over1 this submarine boat was recovered4 ,divers went down1 and found her lying alongside the hull of the ,housatonic1 with the remains of the nine men in her4 ,french ,submarine ,boat ,plongeur4--,the boat termed the ,plongeur was designed by ,admiral ,bougois and ,m4 ,brune1 and was exhibited at the ,paris ,exhibition of #ahfg4 ,she was #bf' long1 #i' deep1 and fitted with centre and bilge keels4 ,she carried two small tanks containing compressed air1 and four large tanks were placed at the bottom of the boat for the purpose of sinking her1 these latter tanks communicating with the water outside and the air tanks4 ,she also was fitted with a compass for steering by1 a water gauge to show the depth of submersion1 and an air gauge to show the pressure of air in the boat4 ,rectangular valves were placed at the bottom of the boat for entrance or exit therefrom1 for the use of divers1 and to affix torpedoes to a ship's bottom4 ,on the top a circular opening for entrance and exit was arranged1 also an iron cupola fitted with bull's-eyes4 ,she was also fitted with an apparatus for spraying water through the air in the interior of the boat on its becoming foul1 and escape valves for releasing any foul air were placed at the top of the boat4 ,the water tanks were filled by means of pumps1 and emptied by means of the compressed air4 ,she was propelled by a three-bladed screw worked by four men4 ,her rate of progression was about four knots per hour4 ,the anchors consisted of two #ae inch shot1 fitted with wire rope cables1 working through watertight stuffing boxes4 ,this vessel has been subjected to some experiments1 but with what results is not generally known4 ,one of the most important uses to which a submarine boat would be put in connection with torpedo operations would be to discover the exact position and number of an enemy's submarine mines1 and if necessary destroy them1 the former being an operation in the present day quite impossible to perform1 and the latter one rarely to be depended on4 ,,footnotes3 ,footnote ,m3 ,extract from ',european ,ships of ,war1' c41 by ,j4 ,w4 ,king1 ,u4,s4,n41 page #cab4 ,footnote ,n3 ,extract from ,engineering1 under date ,april #ac1 #ahgg4 ,footnote ,o3 ,extract from letter of ,captain ,ericsson that appeared in ,engineer1 under date ,nov4 #h1 #ahgh4 ,footnote ,p3 ,extract from the ,engineering of the #ajth of ,january1 #ahgi4 ,,chapter ,,vii4 ,,torpedo ,,operations4 ,a ,,review1 however brief1 of the numerous torpedo operations that have of late years been carried out in actual war1 must prove not only of great interest1 but of material aid to those who may be desirous of studying this branch of naval warfare1 for the experience so gained ought alone to be the basis on which a system of submarine offence and defence should be constructed4 ,no new torpedo invention should be adopted1 however theoretically perfect it may be1 until it has been subjected to a very severe practical test1 under conditions as nearly analogous to those that would occur on active service as it would be possible to obtain4 ,the vast importance of a carefully planned and executed system of submarine defence is an established fact1 and it only remains to discover what are the best weapons for1 and most practicable mode of manipulating a system of submarine offence1 to establish torpedo warfare in all its branches as a necessary function of naval warfare4 ,it would be a mere waste of time to dwell on the ,anglo-,french and ,american wars of the beginning of this century 7#agig-ahab72 though during that period various attempts were made by ,fulton and others to destroy hostile vessels by means of submarine infernal machines1 inasmuch as they all partook more or less of the nature of experiments1 and were all failures1 but come at once to the ,crimean war 7#ahed-ahef71 when what may be termed a systematic employment of torpedoes for harbour defence was first employed4 ,,crimean ,,war 7#ahed-ef74 ,defence of ,sebastopol ,harbour1 c4--,the ,russians employed a large quantity of submarine mines1 both electrical and mechanical1 principally the latter1 in their defence of the harbours of ,sebastopol1 ,sveaborg1 and ,cronstadt4 ,according to ,general ,delafield1 ,u4,s4,a41 the arrangement of the mechanical mines was entirely new1 the conception and idea of an eminent ,russian chemist1 ,professor ,jacobi4 ,electrical ,mines4--,no mention is made by the ,general of the employment of electrical mines1 but the fact of a hulk being captured by the ,allies at ,yenikale1 with a number of torpedoes on board1 and all the arrangements necessary to explode them by electricity1 such as ,voltaic piles1 electric fuzes1 several miles of conducting wire1 c41 is sufficient proof of this type of submarine mine being extensively used by the ,russians in their harbour defences4 ,many of their mechanical mines were picked up by the ,allies1 several of which were found to have their safety caps on4 ,owing to this neglect1 and the smallness of the charge of the torpedoes 7only some #be lbs4 of gunpowder71 it is not to be wondered at that no serious injury was done to any ships of the allied squadron4 ,deterred most probably by the failures of ,bushnell1 ,fulton1 and others in previous years with the submarine and other torpedo boat attacks1 nothing of this description was attempted by either side4 ,russian ,mechanical ,mines4--,the ,russian mechanical mines consisted of barrels of powder fitted with fuzes1 so arranged that a blow would smash a glass tube containing sulphuric acid1 causing the acid to mix with some chlorate of potash1 resulting in combustion and the explosion of the mine4 ,,austro-,,italian ,,war 7#ahei74 ,defence of ,venice by ,von ,ebner4--,during this brief struggle1 defensive torpedo operations were carried out under the direction of ,colonel ,von ,ebner1 of the ,imperial ,austrian ,engineers4 ,the harbour of ,venice was protected by a most elaborate system of submarine mines1 devised by the above-named officer4 ,though the importance of his system was proved by the fact of no attempt being made on ,venice1 yet no opportunity was afforded of practically testing its efficiency4 ,,american ,,civil ,,war 7#ahfa-fe74 ,cause of the ,present ,importance of the ,torpedo4--,the prominent position the torpedo now holds as a most important and legitimate function of naval warfare is owing without doubt to the successful and extensive employment of them on the part of the ,confederates during this long and bloody struggle4 ,reasons which induced the ,confederates to employ ,torpedoes4--,the numerous harbours and navigable rivers in the possession of the ,southerners1 the few ships of war at their disposal1 the overwhelming fleet of the ,northerners1 and the introduction for the first time of ironclads in naval warfare1 are the principal causes which forced the ,confederates to resort to torpedoes as a means of offence and defence4 ,though a few rude and extempore submarine mechanical mines were met with by the ,federals during the earliest part of the war1 it was not until many months after the commencement of hostilities that the ,confederates1 finding themselves quite unable to cope with their rivals on the sea1 set to work in earnest to organise a system of submarine warfare on a grand scale4 ,torpedo ,corps formed1 c4--,loss of ,cairo4--,by ,october1 #ahfb1 a secret service torpedo corps1 with headquarters at ,richmond1 was in full swing1 and the principal harbours and rivers of the ,confederates were systematically protected by means of electrical and mechanical mines1 also a scheme of offence by drifting and spar torpedoes was in preparation1 and in ,december of the same year they experienced the first-fruits of their labour by the total destruction of the ,federal war steamer ,cairo4 ,the following brief review of the numerous torpedo operations carried out by both sides1 and the effect their use had on the war1 will be sufficient to enable the general reader to gain some idea of the vast importance of this submarine weapon in future warfare4 ,fuller and more detailed accounts will be found in ,commander ,s4 ,barnes's1 ,u4,s4,n41 ,colonel ,von ,scheliha's1 and ,captain ,h4 ,steward's torpedo works4 ,every ,species of ,torpedo used--,frame ,torpedoes at ,charleston1 c4--,federal ,ship ,disasters--,small ,effect of ,electrical ,mines--,loss of the ,commodore ,jones1 c4--,every species of submarine mine seems to have been used by the ,southerners for their harbour and river defence1 the most effectual of which were the barrel1 frame1 and ,singer's torpedoes4 ,these were all mechanical1 fired by means of sensitive concussion fuzes4 ,at ,charleston and elsewhere the frame torpedo1 which also acted as an obstruction1 was largely used1 and where this species of mine was known to be laid1 the ,northerners never attempted to force a passage4 ,out of some thirty or forty ,federal ships sunk or injured by torpedoes1 by far the larger proportion of such disasters was effected by means of the barrel and ,singer's mines4 ,though electrical mines were very extensively used on the ,st4 ,james ,river and at ,charleston1 c41 yet only one ,federal steamer1 the ,commodore ,jones1 was sunk1 and only one other1 the ,commodore ,barney1 was injured4 ,case of the ,new ,ironsides4--,the ,federal ship ,new ,ironsides1 at the attack on ,charleston in #ahfc1 was anchored for one hour and a half exactly over a #ejjj lbs4 electrical mine1 which despite all the efforts of the ,confederates could not be exploded4 ,the reason of this was owing to the deterioration of the primer1 due to too constant testing4 ,welden ,railway4--,a notable instance of the effect of torpedoes on the war was the saving of the ,welden line of communication in ,december1 #ahfd4 ,the ,welden ,railway was the principal artery of communication to ,richmond for the ,confederates4 ,to intercept this1 by destroying the railway bridges1 a fleet of nine ,federal gunboats was sent up the ,roanoke river2 when nearly arrived at their destination1 and though every precaution in the shape of bow projecting spars1 creeping1 c41 was taken1 seven of the vessels were either sunk or severely injured by submarine mines4 ,thus the expedition ended in a most disastrous failure4 ,general ,butler's ,attack on ,richmond4--,again1 in ,april1 #ahfd1 ,general ,butler's attack on ,richmond utterly failed1 owing to the ,federal fleet being unable to co-operate with him1 the destruction of the ,commodore ,jones completely checking any further advance of ,admiral ,lee's ships1 thus allowing the ,confederates to employ the garrisons of their river batteries in their land line of entrenchments4 ,more than ,one ,line of ,torpedoes required4--,the capture of the ,spanish fort at ,mobile in ,april1 #ahfe1 by a ,federal fleet under ,admiral ,lee1 proves the necessity of employing more than one line of torpedoes1 where the safety of a position depends almost entirely on those means of defence1 as this one did4 ,here1 though several ,federal vessels were either sunk or severely damaged1 yet the fort was captured4 ,boat ,torpedo ,attacks4--,in regard to boat torpedo attacks1 the ,confederates were only successful in two out of many attempts made by them to sink ,federal vessels4 ,the ,housatonic and ,minnesota4--,these successes were the complete destruction of the ,housatonic by a submarine boat1 fitted with a spar torpedo1 and serious injury caused to the ,minnesota by the explosion of a contact spar torpedo1 carried by an ordinary gig1 commonly termed ,david's4 ,in the former instance the attacking boat was sunk1,q in the latter instance she was uninjured4 ,destruction of the ,albemarle4--,on the part of the ,federals1 ,lieutenant ,cushing with a steam launch fitted with a ,wood and ,lay torpedo1 succeeded in sinking the ,confederate ram ,albemarle4 ,the boat in this instance was swamped by the column of water thrown up on the explosion of the torpedo1 she having been driven full speed at the ,albemarle4 ,ship ,spar ,torpedoes4--,on both sides1 spar torpedoes fitted to the bows of ships1 and also on rafts slung over the bows1 were somewhat extensively used1 but on no occasion were they the means of injuring or sinking any vessels4 ,to increase the difficulties of the ,northerners in searching for submarine mines1 the ,southerners laid down a great number of dummy torpedoes1 also erected false torpedo stations1 and laid false wires4 ,it must always be borne in mind1 in connection with the torpedo operations above detailed1 that the apparatus were very crude1 and the operators at the commencement inexperienced4 ,,paraguayan ,,war 7#ahfd-fh74 ,torpedoes employed by the ,paraguayans4--,during their protracted struggle with the ,brazilians1 the ,paraguayans employed submarine mines for the protection of their river forts1 c4 ,loss of the ,rio ,janeiro--,brazilian ,fleet entrapped4--,on the #bnd of ,september1 #ahff1 the ,brazilian ironclad ,rio ,janeiro1 after being well-battered by the guns of the ,curupaity fort1 was sunk by a torpedo4 ,later on1 near the same place1 a whole fleet of ,brazilian war ships were entrapped by the ,paraguayans1 between two rows of submarine mines1 but owing to faulty arrangements they escaped unharmed4 ,,austrian ,,war 7#ahff74 ,venice1 ,pola1 c41 protected by ,torpedoes4--,during this war1 torpedoes for the defence of ,venice1 ,pola1 c41 were extensively used by the ,austrians1 under the direction of ,baron von ,ebner1 but as in '#ei no opportunity was afforded of proving their practical worth1 though morally they were of great value1 the ,austrian harbours so defended being considered impregnable by the enemy1 and therefore no attempt was made to force them4 ,,franco-,,german ,,war 7#ahgj-ga74 ,little or nothing in the matter of torpedo operations was attempted by the ,germans1 and on the part of the ,french nothing whatever4 ,germans employed ,submarine ,mines4--,electrical and mechanical mines were placed in several of the ,german harbours1 the former containing about #bjj lbs4 of dualine1 the latter some #hj lbs4 of gunpowder4 ,the only attempt to destroy ,french ships by means of offensive torpedoes was made by the ,german vessel the ,grille1 off ,rgen1 which resulted in failure4 ,in laying down and in picking up after the war was over their mechanical mines1 several exploded1 killing some ten to fifteen men4 ,boats necessary4--,towards the end of the war1 the ,germans were constructing special torpedo boats1 believing that such were necessary for the complete defence of harbours4 ,this war added another proof of the moral worth of submarine mines2 the ,french fleet not daring to approach ,german waters supposed to be defended by such means4 ,,russo-,,turkish ,,war 7#ahgg-gh74 ,superiority of ,turkey to ,russia in the matter of ,ships4--,on the ,danube1 in the ,black ,sea1 and ,mediterranean1 where the principal naval portion of the war was carried out1 ,turkey was possessed of a fleet of ships infinitely superior to ,russia1 both in point of numbers and strength1 and therefore1 to enable her to hold her own against this vast superiority of the ,turks1 the ,russians resorted to an extensive employment of torpedoes1 for both offensive and defensive purposes4 ,russian ,torpedoes4--,for many years previous to the outbreak of hostilities in ,april1 #ahgg1 the ,russians had been studying the subject of torpedo warfare in all its branches1 a certain number of their naval and military officers and men having every year passed through a regular course of torpedo study1 at a school specially formed for such a purpose2 they had also laid in large stores of submarine mines1 spar torpedoes1 and were in possession of the ,whitehead and towing torpedoes1 and also several electric lights1 and a few months after war was declared they obtained a fast ,thornycroft torpedo boat4 ,turkish ,torpedoes4--,on the other hand1 the ,turks were only in possession of a number of those huge1 unwieldy #ejj lbs4 buoyant mines1 and one electric light2 circuit closers1 contact mines1 boats 7steam or otherwise7 fitted for use with torpedo1 or offensive torpedoes1 being conspicuous by their absence4 ,thus it will be seen that in the matter of submarine offence and defence1 the ,russians were as superior to the ,turks as the latter were to the former in the matter of ships4 ,turkish ,defensive ,torpedo ,operations4--,the defensive torpedo operations carried out by the ,ottoman naval officers and men were as follows3-- ,the harbour of ,batoum in the ,black ,sea was protected by a few #ejj lbs4 buoyant mines1 arranged to be fired by observation4 ,the mouth of the ,bosphorus and the ,dardanelles were similarly defended4 ,for this work great praise is due to those who executed the work1 for the very strong current and great depth met with in those waters would render such a service a work of great difficulty1 even when properly constructed mooring boats1 and men trained to such1 were employed1 both of which in this particular instance were absent4 ,soulina1 one of the mouths of the ,danube1 and ,suda ,bay 7,candia7 were also protected by similar means4 ,russian ,defensive ,torpedo ,operations4--,the ,russian defensive torpedo operations were very extensive1 their principal harbours in the ,baltic1 as well as those in the ,black ,sea1 were carefully defended by electro-contact mines of the latest type2 so also they protected their numerous bridges across the ,danube1 double and sometimes treble rows of such mines being moored on either side1 and in addition they also placed several mines in the ,danube1 on the chance of destroying the ,turkish ,danube flotilla4 ,destruction of ,turkish ,gunboat ,suna by a ,russian ,submarine ,mine4--,the only instance that occurred during this war of a vessel being sunk by a stationary submarine mine was that of the ,turkish gunboat ,suna1 at ,soulina1 in ,october1 #ahgg1 on the occasion of the unsuccessful attack on that place made by the combined ,russian and ,roumanian flotilla4 ,about #f ,a4,m4 on the morning of the attack1 a loftcha containing two of the enemy's electro-contact mines1 fitted for laying down1 was captured by the ,turks1 from which it was evident that the ,russians had been employed during the night in torpedoing the reach immediately above the ,turkish defences4 ,however1 not heeding this very practical warning1 the ,pacha in command of the ,soulina squadron ordered the ,kartal 7a paddle-wheel tug vessel7 and the ,suna 7an old wooden gunboat7 to reconnoitre up the river2 they accordingly started1 the ,kartal leading the way4 ,at #h4e ,a4,m41 about fifteen minutes after the two vessels had left their moorings1 an explosion was heard1 and almost at the same instant the unfortunate gunboat ,suna was observed to go down head foremost1 her masts only remaining above water4 ,the ,kartal1 which at the time of the catastrophe was some distance in advance1 at once turned back to the assistance of her consort1 and managed to save a number of the gunboat's crew1 this work having to be performed under a galling fire from the allied flotilla4 ,owing to this day being the ,feast of ,bairam1 the unfortunate gunboat was dressed with masthead flags1 thus four ,turkish ensigns fell into the hands of the enemy1 the ,pacha refusing permission for any attempt to be made to save them4 ,the reason that the ,kartal escaped the fate of her consort was due to her only drawing some #e feet of water1 while the ,suna drew at least #h feet4 ,the gunboat struck the mine that sunk her on her port bow1 the effect of the explosion being to completely smash in that side of her bow1 dismount her foremost guns1 and carry away her foremast just above the deck 7the mast remained standing1 though inclined forward72 the second lieutenant of the ,suna1 who was at the time of the explosion standing on her fore bridge1 was thrown off and killed1 and some twelve of the crew were killed and wounded4 ,to complete the destruction of the ,suna1 another torpedo was exploded under her port quarter by the ,russians4 ,the torpedo that was used on this occasion is detailed at page #fh4 ,offensive ,torpedo ,operations4--,the numerous boat torpedo attacks made by the ,russians against the ,turkish fleet will now be considered4 ,the following accounts have been carefully compiled from two sources1 viz4 an article written by ,captain ,chardonneau1 which appeared in the ',revue ,maritime et ,coloniale1' #ahgh1 and which has been recently translated for the ,journal of the ,royal ,united ,service ,institution by ,lieutenant ,j4 ,meryon1 ,r4,n41 and notes taken by the author during his service with the ,imperial ,ottoman ,navy 7#ahgg-gh74 #a,,st ,,affair4 ,the ,batoum ,attack4--,the first torpedo boat attack occurred on the night of the #abth-#acth of ,may at ,batoum4,r ,on the night of the attack there were lying in the harbour several vessels of the ,ottoman fleet1 including ironclads1 transports1 despatch-boats1 c4 ,these vessels were totally unprotected by guard boats1 booms1 electric lights1 c41 and only the usual number of sentries were posted1 the ,turks at that time not quite believing in such boat attacks1 thus offering peculiar advantages for a torpedo attack4 ,four torpedo boats formed the attacking force1 viz4 the ,tchesme1 ,sinope1 ,navarino1 and the ,soukoum ,kal4 ,these boats were carried by a ship of the ,maritime ,company of ,odessa1 named ,grand ,duke ,constantine4 ,she was an iron screw steamer1 able to steam about #aj knots per hour1 and fitted to hoist up the above-mentioned torpedo boats4 ,she was armed with four #d-pounders1 and torpedoes4 ,early in the evening of the #abth the ,constantine left ,poti1 and proceeded off the harbour of ,batoum1 her captain 7,lieutenant de ,vaisseau ,makaroff7 deeming it advisable to lay to seven miles from the harbour1 the supposition that the ,turks had placed submarine mines off the entrance being the cause of his so doing4 ,about #aa ,p4,m4 the four torpedo boats started to the attack1 ,makaroff being in command of one of them4 ,they were all painted sea green1 and possessed a high speed4 ,the night being dark1 and having been despatched some distance off1 they reached the entrance in somewhat straggling order4 ,the ,tchesme1 commanded by ,lieutenant ,zatzarennyi1 and armed with a towing torpedo1 was the first to enter the harbour1 and1 without waiting for her consorts1 dashed at the ,ottoman fleet1 and succeeded in getting close to a large ,turkish paddle-wheel transport1 and her commander dipping his torpedo1 struck the ship under her quarter2 but that little something which so often causes a failure in this mode of warfare occurred1 and no explosion followed the pressing down of the firing key1 much to the chagrin and disgust of ,zatzarennyi4 ,as might be supposed1 by this time an alarm had been raised1 and guns1 rifles1 c41 were fired in and from every direction1 causing the torpedo boats to beat a precipitate and hasty retreat4 ,fortunately the ,turks were not possessed of any steamboats1 nor were any of their ships ready to dash out1 or the defeat would have been a far more disastrous one than was the case4 ,neither of the boats were damaged1 nor any of the crews injured4 ,the failure of this first attempt was due in a great measure to the mode of attack1 no system or unanimity of action on the part of the four commanders being observable2 and also to the somewhat half-hearted support given to the ,tchesme1 for had her three consorts only dashed at the ,turkish ships as boldly1 one at least of the ,ottoman fleet would have been sunk1 the only defence resorted to being their guns and small arms4 ,the moral effect of torpedoes was displayed here1 causing the ,constantine to lay too far off the entrance to the harbour1 thus decreasing the chance of her boats making a successful attack4 ,the ,russian version finishes up by saying1 although this first endeavour was unsuccessful1 the authors of it were received at ,sebastopol with enthusiasm4 #b,,nd ,,affair4 ,the ,matchin ,attack4--,the second attempt was made on the #beth-#bfth of ,may on two ,turkish monitors1 the ,fettu ,islam and the ,duba ,saife1 and a small river steamer1 the ,kilidj ,ali1 lying at anchor off ,matchin4,s ,four ,russian torpedo boats were sent to the attack1 viz4 the ,czarowitch1 ,lieutenant ,doubasoff2 the ,xnie1 ,lieutenant ,chestakoff2 the ,djiquite1 ,midshipman ,persine2 and the ,czarevna1 ,midshipman ,bali4 ,the total number of officers and men carried by these boats on this occasion was forty-six4 ,the night of the attack was rainy1 but not completely dark1 since the moon was above the horizon during nearly the whole of the expedition4 ,the force left ,brailoff at one o'clock on the morning of the #bfth1 and advanced in two columns up the river1 finding great difficulty in stemming the strong current4 ,a boat from the ,duba ,saife1 rowing guard some #ejj yards in advance of the squadron1 observed the approach of the ,russian boats1 but allowed them to pass on their voyage of destruction without attempting to stop them1 or alarm the vessels4 ,on reaching within #aej yards of the ,duba ,saife1 ,dubasoff in the ,czarowitch was challenged1 and failing to give the correct answer was immediately fired at2 but1 nothing daunted by the hail of shot and bullets1 he dashed on1 and succeeded in exploding one of his spar torpedoes on the port side of the ,duba ,saife1 just under her quarter1 a column of water and dbris being thrown up to a height of #abj feet1 which partly filled his boat1 but notwithstanding managed to get safely away4 ,the monitor not sinking as soon as expected1 ,chestakoff in the ,xnie dashed in1 and completed the work of destruction1 the unfortunate ship sinking in a very few minutes after this last explosion4 ,the ,djiquite was struck in the stern1 and had to be run ashore for repairs1 but eventually all four boats reached ,brailoff in safety4 ,the ,russians allowed to neither killed nor wounded1 which1 when the time they were exposed to the fire of the three ,turkish ships 7about twenty minutes71 the number of men 7forty-six7 engaged1 and their very close quarters1 seems miraculous4 ,the ,duba ,saife1 thus lost to the ,turks1 carried two #ab cm4 ,krupp guns1 and a crew of some sixty officers and men1 few of whom were saved4 ,lieutenants ,dubasoff and ,chestakoff were decorated with the #dth ,class of the ,cross of ,saint ,george1 and three seamen received the insignia of the ,order of ,military ,merit4 ,this attack was conducted in a most gallant manner1 and far more systematically than the ,batoum affair4 ,if instead of holding one of the boats in reserve1 which was part of ,dubasoff's plan1 and the remaining three attacking one vessel1 the force had divided itself into two parties1 and had made a simultaneous attack on both the monitors1 the probability is that the ,fettu ,islam would have shared the fate of her consort4 ,the officer of the ,turkish guard boat was tried by court-martial1 but what his ultimate fate was is not generally known4 ,he certainly deserved nothing less than death4 #c,,rd ,,affair4 ,the ,soulina ,attack4--,the third attempt took place on the #ith-#ajth of ,june1 #ahgg1 on a ,turkish squadron lying at anchor off ,soulina4,t ,this squadron consisted of the three ironclads ,feteh ,bulend1 ,moocardemikhair1 and ,idglalieh1 and a tug1 ,kartal4 ,the ,russian attacking force consisted of six torpedo boats1 viz4 the ,no4 #a1 ,lieutenant ,poutschin2 the ,no4 #b1 ,lieutenant ,rojdestvenski2 the ,tchesme1 ,lieutenant ,zatzarennyi2 the ,sinope1 the ,navarino1 and the ,soukoum ,kal4 ,the ,no4 #b was a specially constructed torpedo boat1 #fh feet long1 and very fast4 ,all were armed with spar torpedoes1 with the exception of the ,tchesme1 which carried a towing torpedo4 ,the boats were convoyed from ,odessa by the ,constantine1 some being carried1 and some being towed2 another steamer1 the ,vladimir1 supported her4 ,the ,turkish squadron were anchored in quarter line1 about one mile from the harbour2 the ,kartal1 under weigh1 being used as an advance guard1 and a few boats rowing guard close to the ships being the only means of protection adopted by the ,turks4 ,passive obstructions1 such as booms1 nets1 crinolines1 c41 were not thought of1 much less used4 ,on arriving about five miles from ,soulina1 the boats were formed into two groups1 the first consisting of the ,no4 #a1 the ,no4 #b1 and the ,tchesme1 and despatched on their way4 ,the working of their engines was scarcely heard1 and all lights were carefully hidden by tarpaulins4 ,the first casualty that happened was the disabling of the ,tchesme1 by the electric wire of her towing torpedo fouling the screw1 this obliging her to return to the ,constantine4 ,aided by good fortune1 and by the darkness of the night1 the ,no4 #a and the ,no4 #b succeeded in getting close to 7#cj yards7 one of the ,turkish vessels1 the ,idglalieh1 before being discovered1 when they were at once hailed1 and1 not answering1 a tremendous fire of big guns and rifles was directed on them from the ,idglalieh1 which was promptly followed by that of the whole squadron1 though from the other ships nothing of the boats could be seen4 ,according to the ,russians1 the ,no4 #b succeeded in exploding her torpedo close to1 if not in contact with1 a ,turkish vessel1 but from eyewitnesses on board the squadron only one explosion was heard1 viz4 that of ,lieutenant ,poutschin's torpedo4 ,any way1 no damage whatever was experienced by the ,ottoman squadron4 ,the ,no4 #a came down on the ,idglalieh's starboard bow1 fouled her cable1 and swung alongside1 exploding one of her torpedoes in so doing1 but with no other result than a wetting to those of the ironclad's crew1 who were on the forecastle4 ,alongside ,poutschin remained for some minutes1 but at last managed to get clear1 and then was either sunk by the ,idglalieh's fire1 or1 as he avers1 on finding his screw foul1 he sunk his boat1 rather than let her fall into the hands of the ,turks4 ,poutschin and four of his crew were picked up1 after being some hours in the water1 by the squadron's boats4 ,the ,no4 #b seems to have suffered severely1 her funnel being bent1 the axle of the steering wheel damaged1 sixteen rivets were started1 and the iron keel plate had dropped some #ah inches1 and finally the lower part of her rudder broken1 and one of the blades of her screw bent aft2 part of this damage was no doubt the effect of the explosion of her torpedo1 which was probably not in position1 but unless she ran over some loose stones of the ,soulina breakwater1 the damage to her keel and rudder cannot be accounted for4 ,the second group of boats had followed up the first1 but on hearing the noise of the explosions and roar of the guns and rifles they returned to the ,constantine4 ,that ship1 on observing the firing1 endeavoured to close the land1 but she grounded1 and remained until daylight in a difficult position1 but at last got afloat1 and returned to ,odessa with five out of her six torpedo boats4 ,lieutenant ,rojdestvenski1 the ,commander of the ,no4 #b1 received the #dth ,class of the ,cross of ,saint ,george1 and three seamen the insignia of the ,order of ,military ,merit4 ,on the part of the ,no4 #a and ,no4 #b1 this was a most gallant affair1 though unsuccessful1 but as regards the remainder of the boats the less said the better4 ,had the ,turkish squadron slipped the instant the alarm was given1 and steamed full speed in the direction of ,odessa1 the ,constantine and her convoy might have been cut off4 ,both the ,moorcademikhair and ,feteh ,bulend were #ac knot ships1 and therefore considerably faster than the enemy4 ,but1 as usual1 the ,turks were far too dilatory to take advantage of the occasion4 #d,,th ,,affair4 ,the ,rustchuk ,attack4--,the fourth torpedo attack was made on the afternoon of the #bjth of ,june1 #ahgg1 on a ,turkish monitor off ,rustchuk4 ,the only ,russian torpedo boat sent to the attack on this occasion was a ,thornycroft named the ,choutka1 commanded by ,lieutenant ,skrydloff1 and accompanied by a celebrated ,russian artist1 ,verechtckaguine by name4 ,the instant the torpedo boat was observed1 so well directed and steady a fire was kept up by the monitor that both the lieutenant and the artist were badly wounded1 and the electric wires of the torpedo severed1 thus obliging the ,choutka to beat a retreat4 ,according to the ,russian account1 the monitor was struck by the boat's torpedo spar1 but the above seems the more likely version4 ,this was certainly a most audacious attack1 and had the ,turks only succeeded in hitting the ,choutka with her big gun1 it would have ended fatally for the ,russians2 as it was1 the boat was struck by several bullets1 but none of the crew were wounded4 #e,,th ,,affair4 ,the ,aluta ,attack4--,the fifth attack was made on the #cjth of ,june1 #ahgg1 on a ,turkish monitor off the mouth of the ,aluta1 in the river ,danube4 ,this attempt1 like the last1 took place in broad daylight4 ,four ,russian boats were sent forward1 but in spite of the captain of the ,turkish vessel doing all he could to run the boats down1 none of them succeeded in getting sufficiently near the vessel to enable a torpedo to be placed in contact4 ,the captain of the monitor took the precaution to rig his lower booms out1 and so managed to keep the enemy's boats at a respectful distance1 they imagining that mines were fixed to the ends of the booms4 ,after two hours of this dodging about1 the ,russians1 finding the case hopeless1 abandoned the attack4 ,the ,russian account states--#ast1 that the captain of the monitor was an ,englishman2 #bnd1 that the vessel was protected by nets and torpedoes lashed to the extremities of her booms--both of which statements are radically wrong4 ,the torpedo boats forming the attack were the ,choutka1 ,midshipman ,niloff1 and the ,mina1 ,sub-,lieutenant ,arens1 both armed with the spar torpedo4 ,unless indeed the ,russians acted up to the old proverb which says ,discretion is the best part of valour1 it is difficult to understand how four small easily handled boats could have been for one hour endeavouring to strike a ship 7which ship was at the same time being manoeuvred with a view of running them down7 without either effecting their object or being sunk or damaged in the attempt4 ,the ,russians1 though unsuccessful1 behaved gallantly4 ,midshipman ,niloff was severely wounded1 but no mention is made as to the number of the crew that were killed and wounded1 or of the damage received by the boats4 ,niloff received the #dth ,class of the ,cross of ,st4 ,george1 and ,arens the ,order of ,military ,merit4 ,the ,turkish captain1 ,ali ,bey1 behaved most pluckily and skilfully4 ,the only wonder is that both the boats were not sunk by the monitor's fire4 #f,,th ,,affair4 ,the ,soukoum ,kaleh ,attack4--,the sixth attempt was made on the #bcrd-#bdth of ,august1 #ahgg1 on a ,turkish ironclad1 the ,assari ,shefket1 at the time lying at anchor off ,soukoum ,kaleh4,u ,four torpedo boats composed the attacking force1 viz4 the ,sinope1 ,lieutenant ,pisarefski2 the ,torpedoist1 ,midshipman ,nelson ,hirst2 the ,navarino1 ,lieutenant ,vichnevetski2 and the ,tchesme1 ,lieutenant ,zatzarennyi1 the latter officer being in command4 ,these boats had been brought to the entrance of the harbour by the ,constantine1 and were despatched on their mission of destruction about half past ten4 ,an eclipse of the moon occurred on this night1 and1 taking advantage of this fact1 the four ,russian torpedo boats dashed into the harbour at full speed and made for the ,turkish vessel4 ,fortunately for the safety of his ship and lives of his crew1 the captain of the ,turkish ironclad had several boats rowing guard round his ship1 and otherwise everything on board in readiness for immediate action4 ,on the attacking flotilla nearing the guard boats1 blue lights were burnt1 rifles fired1 c41 and the alarm given to those on the look-out in the ,assari ,shefket4 ,the moment the enemy were within range1 such a well-directed and heavy fire was poured on them that the attack was completely foiled4 ,one of the ,russian torpedoes was exploded1 but failed to do more than throw a quantity of water up4 ,the next morning a pole with torpedo fixed on it was found by the ,turks1 and on the strength of this and the numerous fragments of wood similarly found1 one if not more of the enemy's boats it was supposed must have been sunk1 or much knocked about4 ,this was a much better planned and executed attack1 but was unsuccessful owing to the extreme vigilance of the ,turks4 ,this attempt will always be remembered by the ,turks1 on account of the general order that appeared in the papers on the part of the ,russians1 in which the brilliant exploit and successful destruction of the ,turkish ironclad ,assari ,shefket was set forth at great length2 she at the time that this appeared being quietly at anchor off the dockyard at ,stamboul1 not having received any damage whatever4 #g,,th ,,affair4 ,the ,second ,batoum ,attack4--,the seventh attempt was made on the night of the #bgth-#bhth of ,december1 #ahgg1 on several ,turkish men-of-war anchored in the harbour of ,batoum 7the scene of the first ,russian torpedo attempt and failure74 ,four boats composed the attacking force1 viz4 the ,tchesme1 ,lieutenant ,zatzarennyi1 in command1 armed with a ,whitehead fish torpedo1 containing #cb kilog4 of gun-cotton1 fitted to fire from a tube under the boat's keel2 the ,sinope1 ,lieutenant ,stchelinski1 armed with a similarly charged fish torpedo1 fitted to fire from a raft1 which was towed by the boat1 and two other boats1 armed with spar and towing torpedoes4 ,the means employed at ,batoum for the safeguard of the ,ottoman fleet there against such an attack was that of guard boats and a barrier formed of logs of wood1 with planks secured to them1 so arranged by means of weights that the planks remained perpendicular to the surface of the water when in position4 ,owing to the extreme darkness of the night1 the ,russians managed to evade the guard boats1 and when1 as they imagined1 some #fj to #fe yards from a ,turkish ironclad1 the ,tchesme and ,sinope's ,whitehead fish torpedoes were started on their deadly mission2 but1 owing most probably to the want of practice of manipulating these somewhat delicate instruments1 also to the darkness1 and the slight swell there was on at the time1 both missed their mark1 and were landed high and dry on the beach astern of the ship4 ,one of these weapons was perfect1 the other minus her fore compartment1 this having been knocked off by the torpedo colliding with some hard object4 ,no explosion was heard or seen by the ,turks4 ,this was the second time that the fish torpedo had been employed on actual service1 and1 as in the previous instance1 failed4 ,the guard boats and barrier of the ,turks seem to have been of little avail4 #h,,th ,,affair4 ,the ,final ,attack4--,the eighth and last attempt was made on the night of the #beth-#bfth of ,january1 #ahgh4 ,this was originally intended to be an attack on the ,turkish fleet at ,batoum1 but on entering that harbour the two ,russian torpedo boats1 the ,tchesme1 ,lieutenant ,zatzarennyi1 and the ,sinope1 ,lieutenant ,stchelinski1 were met by a ,turkish revenue steamer1 against which the boats discharged their ,whitehead torpedoes1 resulting in her complete destruction1 at the same time arousing the squadron1 and causing the boats to beat a retreat4 ,though the vessel destroyed was not a frigate1 yet the expedition was successful in so far as proving that it is possible to project ,whitehead fish torpedoes from boats at a distance of #gj to #ij yards from an enemy's ship1 on a dark night1 and strike her with them4 ,this concludes the whole of the offensive torpedo operations that were carried out during the war1 of which two out of eight attempts were successful1 which is without doubt a fair percentage4 ,there seems every probability that the present struggle between ,chili and ,peru1 in the ,pacific1 will afford torpedoists further experience of the various offensive torpedoes1 when subjected to the test of active service4 ,,footnotes3 ,footnote ,q3 ,see page #ahe4 ,footnote ,r3 ,a ,turkish port1 situated on the east coast of the ,black ,sea1 capable of holding several large ships when anchored head and stern1 but otherwise only a few4 ,footnote ,s3 ,a town situated on the south bank of the ,danube1 about eight miles from ,brailoff4 ,footnote ,t3 ,one of the principal mouths of the ,danube4 ,footnote ,u3 ,a place taken from the ,russians in the early part of the war1 situated on the east coast of the ,black ,sea4 ,,chapter ,,viii4 ,,on ,,explosives4 ,,explosion may be defined as the sudden or extremely rapid conversion of a solid or liquid body of small bulk into gas or vapour1 occupying very many times the volume of the original substance1 and which in addition is highly expanded by the heat generated during the action4 ,this sudden or very rapid expansion of volume is attended by an exhibition of force which is more or less violent1 according to the constitution of the original body and the circumstances of the explosion4 ,any substance capable of undergoing such a change on the application of heat or other disturbing cause is called an explosive4 ,explosive ,force4--,explosive force is directly proportional to the heat of combustion and the volume of gas1 and inversely to the specific heat of the mixed products4 ,explosive effect is directly proportional to the volume of gas produced and the temperature of the explosion1 and inversely as the time required for the change to take place4 ,explosive ,effect and ,force compared4--,explosive effect depends upon the rapidity with which the conversion is effected1 while the same amount of explosive force may act suddenly or gradually4 ,as before stated1 explosions are more or less violent according to the circumstances under which they take place4 ,these may be considered as follows3-- #a4--,the physical state of the explosive substance4 #b4--,the external conditions under which the explosive body is fired4 #c4--,the mode of firing4 ,the ,physical ,state of the ,explosive ,substance4--,numerous instances may be cited to show the influence the physical condition of an explosive body has upon its explosion4 ,thus1 gunpowder may1 by merely varying the size1 shape1 and density of the grain1 be made to ignite rapidly but burn comparatively slowly1 or be made to ignite more slowly1 but once inflamed to burn very rapidly4 ,again1 gun-cotton in a loose1 uncompressed state1 will1 if ignited1 only flash off2 if it is spun into threads or woven into webs1 its rate of combustion may be so much reduced that it can be used in gunnery or for a quick fuze2 while if powerfully compressed and damp it burns slowly4 ,wet gun-cotton requires a primer of dry gun-cotton and a fulminate fuze to explode2 dry1 it may be exploded by a fulminate fuze1 c4 ,then nitro-glycerine1 when exploded by #ae grains of fulminate of mercury1 and at a temperature above #dj ,f41 is very violently detonated2 below #dj ,f4 it freezes and cannot be similarly exploded4 ,to obtain the full effect of all explosives1 confinement is absolutely necessary4 ,the more rapid the explosion the less confinement required1 approaching in the case of some explosives to so small an amount that it need not1 for practical purposes1 be considered4 ,thus a charge of nitro-glycerine or gun-cotton1 when detonated in the open air1 will destroy wrought iron rails1 large blocks of stones1 balks of timber1 c4 ,in the case of the former body1 the confinement of the atmosphere is sufficient4 ,in the latter1 the mechanical cohesion due to compression is sufficient restraint4 ,abel states that if the film of atmosphere surrounding the nitro-glycerine1 not exceeding #a_/ajjj inch in thickness1 be removed1 the explosive effect is much lessened4 ,a large charge of gunpowder fired in the ordinary way under water requires a strong case to retain the gases until the action has become general1 or1 owing to its slow rate of burning1 the case would be broken before the whole of the charge had been ignited1 and part of the charge drowned4 ,this is often to be noticed when firing fine-grained powder in heavy guns4 ,igniting the charge at several points diminishes the confinement needed4 ,mode of ,firing4--,the application of heat1 directly or indirectly1 is the principal means of causing an explosion4 ,the flame from a percussion cap or primer1 or a platinum wire heated to incandescence by an electric current1 will directly ignite a charge4 ,friction1 concussion1 c41 will indirectly ignite a charge due to the conversion of mechanical energy into heat4 ,it would appear that when one explosive body is used as a means of firing another1 the resultant explosion is due to the blow suddenly formed by the gas of the firing charge acting percussively upon the mass to be exploded4 ,if such were the case1 then the most powerful explosive would be the best agent for causing an explosion4 ,but it is not so4 ,for example1 nitro-glycerine1 which is far more powerful than fulminate of mercury1 requires more than #ajjj grains to explode gun-cotton1 while only #ae grains of the latter is needful for the same work1 c4 ,a small quantity of an explosive substance which is sensitive to friction or percussion is often used to ignite the original charge4 ,detonation4--,the instantaneous explosion of the whole mass of a body is defined as detonation4 ,the essential difference between an explosion and a detonation is the comparative suddenness of the transformation of the solid or liquid explosive substance into gas and vapour4 ,some explosive bodies1 such as the fulminates1 c41 always detonate1 while the detonation of others depends on the mode of firing4 ,nitro-glycerine always explodes violently1 but when fired with an initiatory charge of fulminate of mercury it is much more powerful than when fired with gunpowder4 ,compressed gun-cotton in the air-dry state can be detonated by #b grains of fulminate of mercury embedded in the material1 but when it contains #c per cent4 of water over and above the #b per cent4 which exists normally in the air-dry substance1 #ae grains of the fulminate will not always do so4 ,theory of ,detonation4--,the theory of detonation is not yet thoroughly understood4 ,that it is not alone due to the heat caused by the impact of the mechanical energy of the particles of gas1 set free from the initiatory charge on the principal mass1 is proved by the fact of its being possible to detonate wet gun-cotton4 ,professor ,bloxam terms detonation to be sympathetic explosion4 ,experiments carried on in ,england by ,professor ,abel1 and in ,france by ,,mm4 ,champion and ,pellet1 tend to show that it is due to the vibratory action of the detonating agent4 ,thus a glass may withstand a strong blow1 though a particular note or vibration will smash it4 ,all explosive compounds and mixtures1 including gunpowder1 are susceptible of violent explosion through the agency of a detonation4 ,roux and ,sarrau4--,roux and ,sarrau divide explosions into two orders3-- #ast order4--,detonations4 #bnd order4--,simple explosions4 ,simple explosions are produced by direct inflammation1 or by a small charge of gunpowder4 ,detonations are obtained from nitro-glycerine1 gun-cotton1 c41 by exploding with fulminate of mercury4 ,they state that fulminate of mercury does not detonate gunpowder2 but if the exploding charge is a small amount of nitro-glycerine1 itself detonated by fulminate of mercury1 then an explosion of the first order is obtained4 ,the relative effects were approximately measured by determining the quantities necessary to rupture small cast iron shells of supposed equal strength4 ,results of their ,experiments4--,the following are some of the results3-- ---------------------------------------- -- ,explosive ,effect4 --------------------------- #bnd ,order4 #ast ,order4 ---------------------------------------- - ,gunpowder #ajj #dcd ,gun-cotton #cjj #fdf ,nitro-glycerine #dhj #ajac ---------------------------------------- - ,according to the above table1 nitro-glycerine is more than ten times1 and gun-cotton more than six times1 as powerful as gunpowder fired in the ordinary way 7#bnd order74 ,the want of reciprocity between two detonating agents is shown in a remarkable degree by the following experiments1 carried out by ,professor ,abel3-- #a4--,the detonation of #a_/d ounce of gun-cotton 7the smallest quantity that can be thus applied7 induced the simultaneous detonation of nitro-glycerine1 enclosed in a vessel of sheet tin1 and placed at a distance of #a inch from the gun-cotton4 #b4--,the detonation of #a_/b ounce of gun-cotton produces the same effect with an intervening space of #c inches between the substances4 #c4--,the detonation of #b ounces of nitro-glycerine in close contact with compressed gun-cotton failed to accomplish the detonation of the latter1 which was simply dispersed in a fine state of division1 in all the instances but one1 in a large number of experiments4 ,explosive agents are divided into explosive mixtures and compounds4 ,in the former the ingredients are mechanically mixed1 and can be separated by mechanical means4 ,in the latter the ingredients are chemically combined1 and can only be separated by chemical change4 ,torpedo ,explosive ,agents4--,the explosive agents that are practically the most important1 as far as their employment as torpedo charges are concerned1 are as follows3-- ,explosive ,mixtures4--,a4--,explosive mixtures4 #a4--;,gunpowder4 ,nitrate class #b4--;,ammonium picrate1 or picric powder4 ,explosive ,compounds4--,b4--,explosive compounds4 #a4--,nitro-glycerine4 #b4--;,dynamite 7,no4 #a74 #c4--;,gun-cotton4 #d4--;,fulminate of mercury4 ,a4--,,explosive ,,mixtures4 ,gunpowder4--,this explosive mixture is composed of seventy-five parts of nitre 7saltpetre71 fifteen parts of charcoal1 and ten parts of sulphur4 ,on being ignited1 the oxygen which is feebly held by the nitrogen combines with the carbon1 forming carbonic oxide gas1 whilst the sulphur unites with the potassium of the nitre1 the whole combination being accompanied by a great evolution of heat and expansion of gas1 and the nitrogen is set free4 ,properties1 c4--,a spark1 friction between hard bodies1 or a temperature of #egb ,f41 are any of them sufficient to cause an explosion of gunpowder4 ,slight moisture1 due to damp air1 c41 produces caking and deterioration4 ,wetting causes permanent destruction4 ,frost does not injure it4 ,it can be fired by ordinary methods4 ,it can be transported and handled with safety and great ease4 ,it is not a suitable explosive agent for torpedoes1 on account of its liability to be injured by damp1 as well as its not being sufficiently violent1 though for the sake of convenience1 c41 it is often employed for such work4 ,the effect produced by the explosion of a charge of gunpowder1 ignited by the ordinary method1 is that of an uplifting rather than a shattering effect4 ,this evil may be greatly remedied1 when gunpowder is used as the charge of a torpedo1 by firing it with a detonator1 by which means its fullest explosive effect is developed4 ,picric ,powder4--,the picrates are salts of picric acid4 ,picric acid is formed by the action of nitric acid on carbolic acid4 ,the picrate employed by ,professor ,abel is prepared from picric acid and ammonium4 ,this preparation1 or salt mixed with nitre 7saltpetre71 forms ,abel's picric powder4 ,properties1 c4--,it is prepared for use in a similar manner to gunpowder1 and it can be handled in the same way4 ,it is less violent than dynamite or gun-cotton1 though much more so than gunpowder4 ,it is difficult to explode it by blows or friction4 ,if flame be applied to it1 the part touched burns1 but the combustion does not become general4 ,this explosive agent will probably be used for spar torpedoes1 when gun-cotton or dynamite are not employed4 ,b4--,,explosive ,,compounds4 ,nitro-glycerine4--,nitro-glycerine is formed by the action of nitric acid upon glycerine at a low temperature4 ,the manufacture of this compound consists1 first1 in the slow mixture of the glycerine with the acid1 at a low temperature2 secondly1 in washing the nitro-glycerine from the excess of acid with water4 ,the nitric acid before use is mixed with a certain proportion of strong sulphuric acid1 so that the water formed during the reaction may be taken up1 and thus any dilution of the nitric acid is prevented4 ,nitro-glycerine is composed of carbon1 hydrogen1 nitrogen1 and oxygen1 as indicated by the equation ,c#c;,h#e,n#c,o#i4 ,properties1 c4--,at ordinary temperatures nitro-glycerine is an oily liquid1 having a specific gravity of #af4 ,freshly made it is creamy white and opaque1 but clears and becomes colourless on standing for a certain time1 depending on the temperature4 ,it does not mix with1 nor is it affected by1 water4 ,it has a sweet1 aromatic taste1 and produces a violent headache if placed upon the tongue4 ,the opaque1 freshly made nitro-glycerine does not freeze until the temperature is lowered to #c-e below zero1 ,f41 but1 when cleared1 it freezes at #ci-dj ,f4 ,nitro-glycerine freezes to a white crystalline mass1 and in this state it can be thawed by placing the vessel containing it in water1 at a temperature not over #ajj ,f4 ,if flame is applied to freely exposed nitro-glycerine1 it burns slowly without explosion4 ,nitro-glycerine in a state of decomposition becomes very sensitive1 exploding violently when struck1 even when unconfined4 ,pure nitro-glycerine does not spontaneously decompose at any ordinary temperature1 but if it contains any free acid1 then decomposition may happen4 ,when pure1 it is not sensitive to friction1 or moderate percussion4 ,if struck with a hammer1 only the particle receiving the blow explodes1 the remainder being scattered4 ,the firing point of nitro-glycerine is about #cef ,f41 though it begins to decompose at a lower temperature4 ,the mode of firing nitro-glycerine usually employed is that of a fulminate of mercury detonating fuse4 ,nitro-glycerine in the frozen state cannot be fired even by large charges of fulminate4 ,in one instance1 #afjj lbs4 of liquid nitro-glycerine exploded in a magazine containing #fjj lbs4 of the same substance in a frozen state1 but failed to fire the latter1 only breaking it up and scattering it in every direction4 ,dynamite4--,this explosive compound is merely a preparation in which nitro-glycerine is itself presented for use1 its explosive properties being those of the nitro-glycerine contained in it1 as the absorbent is an inert body4 ,dynamite is formed of seventy-five parts of nitro-glycerine absorbed by twenty-five parts of a porous siliceous earth or kieselguhr4 ,the best substitute for kieselguhr is ashes of bog-head coal4 ,dynamite is a loose1 soft1 readily moulded substance1 of a buff colour4 ,the preparation of dynamite is very simple4 ,the nitro-glycerine is mixed by means of wooden spatulas with the fine white powder 7kieselguhr7 in a leaden vessel4 ,it freezes at #ci-dj ,f41 and when solidly frozen cannot be exploded1 but if in a pulverised state it can be exploded1 though with diminished violence4 ,it can be easily thawed1 by placing the vessel containing it in hot water4 ,friction or moderate percussion does not explode it4 ,its firing point is #cef ,f4 ,if flame be applied to it1 it burns with a strong flame4 ,it is fired by means of fulminate of mercury1 and its explosive force is about seven times that of gunpowder4 ,for ground and buoyant mines1 where actual contact between the hostile vessel and the torpedo will be rarely achieved1 this being next to nitro-glycerine the most violent of all known explosive agents1 and being cheaply and readily procured1 is the very best explosive for such torpedoes4 ,that it is not generally adopted is owing to its containing a large proportion of that seemingly dangerous substance1 nitro-glycerine1 which makes the handling of dynamite a somewhat hazardous operation4 ,according to ,professor ,abel1 there are now as many as fifteen dynamite factories in different parts of the world 7including a very extensive one in ,scotland7 working under the supervision of ,mr4 ,nobel1 the originator of the nitro-glycerine industry2 and six or seven other establishments exist where dynamite or preparations of very similar character are also manufactured4 ,the total production of dynamite in #ahfg was only eleven tons1 while in #ahgh it amounted to #fadj tons4 ,this explosive compound is most extensively used for general blasting purposes all over the world1 and for this purpose1 owing to its cheapness and the convenience in manipulating it1 is far superior to compressed gun-cotton4 ,gun-cotton is formed by the action of concentrated nitric acid on cotton1 its composition being indicated by the formula ,,ch#g7,,no#b7c,o#e4 ,professor ,abel's process for manufacturing pulped and compressed gun-cotton is as follows3-- ,cotton waste is the form of cotton used2 it is picked and cleaned1 thoroughly dried at #afj ,f41 and then allowed to cool4 ,the strongest nitric and sulphuric acids are employed1 mixed in the proportion of one part of the former to three of the latter by weight4 ,these are mixed in large quantities1 and stored in cast-iron tanks4 ,the cotton in #a-lb4 charges is immersed in the acid mixture1 which is contained in a trough surrounded by cold water4 ,after being subjected to the action of the acid for a short space of time1 the cotton is taken up1 placed upon a perforated shelf1 and as much as possible of the acid squeezed out of it4 ,it is then put into jars1 covered with fresh acid1 and the jars placed in fresh water1 remaining there for twenty-four hours4 ,to remove the acid1 the gun-cotton from the jars is thrown into a centrifugal strainer1 by which nearly all the acid is expelled4 ,it is then diffused quickly in small quantities through a large volume of water1 and again passed through a centrifugal machine4 ,the next process is that of thoroughly washing the gun-cotton1 for the purpose of removing the traces of the acid still adhering to it4 ,by pulping1 which operation is performed in pulping engines or beaters1 the washing is expeditious and thorough4 ,a beater is an oblong tub in which is placed a revolving wheel carrying strips of steel on its circumference4 ,from the bottom under the wheel project similar steel strips4 ,the action of this machine is as follows3-- ,by the rotation of the wheel1 the gun-cotton which is suspended in water circulates around the tub1 and is drawn between the two sets of steel projections1 by which it is reduced to a state of pulp4 ,the bottom of the tub is movable1 and thus the space through which the gun-cotton must pass may be contracted1 as the operation proceeds4 ,the pulping being complete1 the contents are run into poachers for the final washing4 ,a poacher is a large oblong wooden tub4 ,on one side at the middle is placed a wooden paddle-wheel1 which extends half way across the tub4 ,in the poacher the pulped gun-cotton is stirred for a long time with a large quantity of water4 ,the revolution of the paddle-wheel keeps up a constant circulation1 and care is taken that no deposit occurs in any part of the tub4 ,having converted the cotton into gun-cotton1 reduced it to a state of pulp1 and thoroughly washed it1 the next process is to separate the water from the pulp1 and compress it into cakes or discs4 ,this is accomplished by means of two presses1 the first of which has #cf hollow cylinders1 in which perforated plungers work upwards4 ,these plungers having been drawn down1 the cylinders are filled with the water-laden pulp1 and their tops covered with a weight2 the plungers are then forced up by hydraulic power1 compressing the pulp1 and forcing the water to escape through their perforations4 ,the second one is used to more solidly compress the cylindrical masses of gun-cotton formed by the action of the first press1 a pressure of #f tons to the inch being in this case applied4 ,about #f per cent4 of moisture still remains in the discs1 which can be readily removed by drying4 ,properties4--,cotton converted into gun-cotton is little changed in appearance1 though the latter is harsher to the touch than the former4 ,if a flame be applied to dry loose gun-cotton1 it flashes up1 without explosion2 if compressed it burns rapidly1 but quietly4 ,moist compressed gun-cotton under the same circumstances burns away slowly4 ,gun-cotton containing #ab to #ad per cent4 of water is ignited with much difficulty on applying a highly heated body4 ,as it leaves the hydraulic press upon being converted from the pulped state to masses1 it contains about #ae per cent4 of water2 in this condition it may be thrown on to a fire or held in a flame without exhibiting any tendency to burn2 the masses may be perforated by means of a red-hot iron1 or with a drilling tool1 and they may with perfect safety be cut into slices by means of saws revolving with great rapidity4 ,if placed upon a fire and allowed to remain there1 a feeble and transparent flame flickers over the surface of the wet gun-cotton from time to time as the exterior becomes sufficiently dry to inflame2 in this way a piece of compressed gun-cotton will burn away very gradually indeed4 ,to test the safety of wet gun-cotton1 the following two experiments among many have been made3-- ,quantities of wet gun-cotton1 #bj cwt4 each1 packed in one instance in a large1 strong wooden case1 and in the other in a number of strong packing cases1 were placed in small magazines1 very substantially built of concrete and brickwork4 ,large fires were kindled around the packages in each building1 the doors being just left ajar4 ,the entire contents of both buildings had burned away1 without anything approaching explosive action1 in less than two hours4 ,this comparatively great safety of wet gun-cotton1 coupled with the fact that its detonation in that state may be readily accomplished through the agency of a small quantity of dry gun-cotton1 termed a primer1 which1 by means of a fulminating fuze1 or detonator1 is made to act as the initiative detonating agent1 gives it important advantages over other violent explosive agents1 when used for purposes which involve the employment of a considerable quantity of the material1 on account of the safety attending its storage and necessary manipulation4 ,from experiments conducted by engineer officers in ,austria1 it was found that if boxes containing dry compressed gun-cotton are fired into from small arms1 even at a short range1 the gun-cotton is generally inflamed1 but never exploded1 the sharpness of the blow essential to effect an explosion1 which the bullet might otherwise give1 being diminished by its penetration through the side of the box before reaching the explosive4 ,wet gun-cotton1 containing even as little as #ae per cent4 of water1 is never inflamed on these conditions4 ,dynamite1 on the other hand1 is invariably detonated when struck by a bullet on passing through the side of the box4 ,gun-cotton is insoluble in and unaffected by water4 ,the firing point of gun-cotton is about #cfj ,f4 ,the temperature of explosion of gun-cotton is about #hgjj ,f41 being more than double that of gunpowder4 ,gun-cotton is not sensitive to friction or percussion4 ,if not perfectly converted or thoroughly washed1 gun-cotton is liable to spontaneous decomposition1 which under favourable conditions may result in explosion4 ,compressed gun-cotton is free from such danger1 as it may be kept and used saturated with water4 ,it is stored in the wet state1 care being taken that it is not exposed to a temperature that will freeze the water in the cakes1 as if this occurs they are liable to be disintegrated by the expansion of the water in freezing4 ,gun-cotton is the agent most extensively used for all kinds of military engineering and submarine operations in ,great ,britain1 it being especially manufactured by the ,english government for that express purpose2 but in other countries it is not so manufactured1 and therefore1 as it is little used for other than military purposes1 it is not to any extent privately manufactured1 as is the case with other explosives1 such as dynamite1 dualine1 lithofracteur1 c41 and thus1 in case of war1 would be somewhat difficult to obtain out of ,england4 ,compared with dynamite1 it is not so violent1 and occupies more space1 weight for weight1 and also requires a more complicated means of detonating it4 ,on the other hand1 gun-cotton is infinitely safer to store and manipulate1 and is not so subject to detonation by concussion 7not being so sensitive7 as dynamite4 ,fulminate of ,mercury4--,fulminate of mercury is formed by the action of mercuric nitrate and nitric acid upon alcohol4 ,the mode of preparation is as follows3-- ,dissolve one part of mercury in twelve parts of nitric acid1 and pour this solution into twelve parts of alcohol4 ,pour this mixture into a vessel which is placed in hot water until it darkens and becomes turbid and begins to evolve dense white fumes1 then remove it from the water4 ,the reaction goes on1 with strong effervescence and copious evolution of dense white ethereal vapours4 ,if red fumes appear1 cold alcohol should be added to check the violence of the action4 ,the operation should be performed at a distance from a fire or flame1 and in a strong draught1 so that the vapours may be carried off4 ,when the liquid clears1 and the dense white fumes are no longer given off1 further action is stopped by filling up with cold water4 ,the fulminate settles to the bottom of the vessel as a grey crystalline precipitate4 ,the liquid is then poured off1 and the fulminate washed several times by decantation or upon a filter4 ,dry fulminate of mercury explodes violently when heated to #cfg ,f41 when forcibly struck by the electric spark1 c4 ,when wet it is inexplosive1 and therefore it is always kept wet1 being dried in small amounts when required for use4 ,fulminate of mercury is applied in many ways1 either pure or mixed with other substances1 as in percussion caps1 percussion powder1 primers1 detonators1 c4 ,for the purpose of detonating nitro-glycerine or its preparations1 #ae grains of the fulminate are sufficient1 but to detonate gun-cotton #be grains are necessary4 ,the fulminate in detonating fuzes should be enclosed in a copper case or cap1 and must never be loose4 ,the fulminate should be wet when charging the detonators1 as it is very dangerous to handle when dry4 ,great care is requisite in handling this explosive compound4 ,in addition to the foregoing explosive compounds and mixtures1 the following explosive agents have also been employed for the purposes of submarine operations1 though only to a small extent4 ,dualin4--,dualin is a nitro-glycerine preparation formed by mixing sawdust and saltpetre with that substance4 ,this preparation1 inferior to dynamite1 was employed by the ,germans as the explosive agent for their submarine mines during the ,franco-,german war 7#ahgj-ga74 ,lithofracteur4--,lithofracteur is also a preparation of nitro-glycerine4 ,it is composed of the following materials3--,nitro-glycerine1 kieselguhr1 coal1 soda1 saltpetre1 and sulphur4 ,this explosive agent1 also inferior to dynamite1 is used1 though not very extensively1 by the ,french for their submarine mines4 ,horsley's ,powder4--,horsley's powder is a chlorate mixture formed of potassium1 chlorate1 and galls4 ,this explosive mixture was formerly used by ,captain ,harvey for his towing torpedo1 but has recently been discarded for compressed gun-cotton4 ,abel's ,detonation ,experiments4--,the following are the results of experiments carried out by ,professor ,abel1 ,c4,b41 ,f4,r4,s41 on the subject of detonation3-- #a4--;,a fuze containing rather more than #a ounce of gunpowder1 strongly confined1 exploded in contact with a mass of compressed gun-cotton1 only inflames it1 although the explosion of the fuze is apparently a sharp one4 #b4--de grains of fulminate of mercury1 exploded unconfined on the surface of a piece of compressed gun-cotton1 only inflames or disperses it4 #c4--;,a fuze containing #i grains of fulminate of mercury1 strongly confined1 exploded in contact with compressed gun-cotton1 or dynamite1 detonates it with certainty4 #d4--;,an equal quantity of fulminate of mercury1 similarly confined1 does not detonate uncompressed gun-cotton in which it is imbedded1 but merely disperses and inflames it4 #e4--aej grains of compressed gun-cotton1 detonated in proximity to dynamite1 detonates the latter4 #f4--c ounces of dynamite1 and very much larger quantities1 detonated in contact with compressed gun-cotton1 only disperses it4 #g4--;,a wrought-iron rail can be destroyed by detonating #h ounces of compressed gun-cotton placed unconfined on the rail4 #h4--;,a piece of wet gun-cotton1 quite uninflammable1 removed from a fire1 and detonated upon a block of granite1 using a small primer of dry gun-cotton1 shatters the block4 #i4--;,a submerged charge of wet gun-cotton1 open on all sides to the water1 and merely confined around the dry initiative1 or primer1 by means of a net1 can be exploded4 ,explosive ,agents in ,torpedoes4--,the explosive agents that at the present time are most generally used in torpedoes are gunpowder1 gun-cotton in the wet compressed state1 and dynamite1 and these may be compared as to their properties and their explosive effects4 ,gunpowder4--,gunpowder is a familiar material1 in general use for all military purposes4 ,it can be handled and transported with safety and ease1 and it can be fired by ordinary methods4 ,but for submarine purposes it has the disadvantage of being very easily injured by water1 so that it is absolutely necessary to enclose it in water-tight cases4 ,gun-cotton4--,gun-cotton is free from liability to accidents1 and in this matter1 and the safety of its manufacture1 it compares favourably with gunpowder4 ,it is peculiarly adapted to submarine work1 being unaffected by water4 ,and as it may be kept in water1 ready for use1 it can be safely carried on board ship in large quantities4 ,it is far more violent in its action when detonated than gunpowder4 ,the chief objection to its use is1 that being applied only for special purposes1 it is not readily obtained4 ,also it requires a peculiar and somewhat complicated mode of firing it4 ,dynamite4--,dynamite is more easily manufactured than the two foregoing explosives4 ,the fact of it containing nitro-glycerine1 which has a bad reputation1 has militated against its use as a torpedo explosive agent1 though for blasting purposes it is most extensively used4 ,though not directly affected by water1 its firing is hindered when diffused through water4 ,another disadvantage is its high freezing point4 ,like gun-cotton1 it requires special means to fire it1 though much simpler1 and also is much more powerful than gunpowder4 ,the explosive effect of dynamite or gun-cotton is a rending or a shattering one1 while that of gunpowder is an uplifting or heaving one4 ,again1 it is necessary when using gunpowder that the object be in the line of least resistance1 but with dynamite or gun-cotton the effect is nearly equal in every direction1 therefore for submarine operations1 either dynamite or gun-cotton is the explosive agent that should be invariably used4 ,size of ,torpedo ,charges4--,for permanent mines1 a charge of #gjj lbs4 to #ajjj lbs4 of gun-cotton is quite sufficient1 though too large a charge cannot be employed1 except as regards the matter of convenience4 ,for buoyant mines1 #ejj lbs4 to #gjj lbs4 of gun-cotton is an ample charge1 and for contact mines1 #bjj lbs4 to #cjj lbs4 of gun-cotton is sufficient4 ,in spar torpedoes1 where lightness is a consideration1 gun-cotton charges of #cj lbs4 to #ej lbs4 will be found ample1 and similarly in the case of the towing or locomotive torpedoes4 ,of course1 with regard to such a submarine weapon as the ,lay torpedo boat1 any size charge may be carried1 according to the wish of the builder4 ,torpedo ,explosions illustrated4--,at ,fig4 #aff is represented a sketch of a torpedo explosion1 from a photograph taken at the moment the column of water was at its greatest elevation4 ,the torpedo contained #dcb lbs4 of gun-cotton1 and was exploded under #bg feet of water4 ,the height of the column thrown up measured #ha feet1 and the diameter at the base #acb feet4 ,illustration3 ,,submarine ,,mine ,,explosion4 ,,plate ,,lii ,illustration3 ,,submarine ,,mine ,,explosions4 ,,plate ,,liii ,at ,fig4 #afe is shown a sketch of two submarine mine explosions from an instantaneous photograph2 the schooner which is shown in the sketch happened to be passing at the moment of explosion1 thus affording a comparison as to the size of the columns of water thrown up4 ,the column on the left was due to the explosion of a submarine mine containing #ajj lbs4 gunpowder at a depth of #aj feet below the surface4 ,that on the right was the result of an explosion of a similar mine1 but at a depth of #da feet below the surface4 ,its extreme height was #djj feet4 ,,chapter ,,ix4 ,,torpedo ,,experiments4 ,,the following are some of the more important torpedo experiments that have been carried out in ,england and ,europe1 to investigate the subject of submarine explosions as applied to ships and to mines1 c41 these experiments extending over a space of thirteen years4 ,experiment at ,chatham1 ,england1 #ahfe4--,this experiment was carried out to ascertain the effect of gunpowder torpedoes on the bottom of a wooden ship4 ,target3--,h4,m4,s4 ,terpsichore1 a wooden sloop of war4 ,torpedo3--#aej lbs4 of fine-grained powder4 ,two were used4 ,they were placed on the ground1 about #ac' below the ship's keel1 and #b' horizontally clear of her side4 ,effect of explosion3--,a hole of about #d' radius was made1 about #ai' nearly vertical from the charge2 the ,terpsichore sinking a few minutes after the explosion4 ,experiment in ,austria4--,the object of this experiment was to ascertain the effect of a very large charge of gun-cotton exploded at some distance from the side of a wooden vessel4 ,target3--,a wooden sloop4 ,torpedo3--#djj lbs4 of gun-cotton1 placed #aj' below the surface of the water1 and #bd' horizontally from the bottom of the vessel4 ,effect of explosion3--,complete destruction of the vessel4 ,experiments at ,carlscrona1 ,sweden1 #ahfh4--,these experiments were made to investigate the effect of submarine contact mines1 charged with dynamite1 against a strong wooden vessel1 as well as against a double-bottomed iron vessel4 ,they were carried out under the supervision of ,lieut4-,colonel ,zethations1 of the ,royal ,swedish ,navy4 ,target3--,the hull of a #fj gun frigate1 which had been built in #ahdd2 it had been cut down to the battery deck1 and the copper removed4 ,her timbers and planking were quite sound2 timbers of oak about #ac square1 and #a apart2 planking of ,swedish pine1 #e-a_/b2 bottom strengthened inside with wrought-iron diagonal bands1 #f by #a-a_/d2 inside planking running half way up to the battery deck of oak2 #f thick4 ,this completes the wooden target4 ,on the port side a quadrangular opening was made1 and fitted with a construction representing a strong double iron bottom1 firmly fastened to an oaken frame that had been put on inside1 on the four sides of the opening1 and with through-going bolts1 #a in diameter1 to the timbers4 ,torpedoes3--,no4 #a4--ac lbs4 dynamite1 enclosed in #a_/ab iron case4 ,it was placed on the starboard side1 amidships1 #g' below the water line1 and #b' #b from the bottom of the ship4 ,no4 #b4--af lbs4 dynamite1 enclosed in a glass vessel4 ,it was placed on the starboard side1 #g-c_/d' below the water line1 #c' from the bottom of the ship1 and #dj' from her stern4 ,no4 #c4--af lbs4 dynamite1 enclosed in #a_/ab iron case4 ,it was placed on the port side1 #e-c_/d' below the water line1 #b' from the bottom of the ship1 and #cj' from her stern4 ,no4 #d4--aj lbs4 dynamite1 in a case as above4 ,it was placed on the port side1 #f-a_/b' below the water line1 #b-a_/f' from the bottom of the ship1 and #gj' from her stern4 ,no4 #e4--ac lbs4 dynamite1 in case as above4 ,it was placed #g-a_/c' below the water line1 #b-a_/f' from the centre of the iron bottom4 ,these five torpedoes were fired at the same moment4 ,effect of explosion3--,the hull of the ship was lifted about a foot1 and sunk in #a-a_/b minutes4 ,no4 #a ,mine4--,timbers broken and thrown inside1 into the hold1 on a space of about #ae' #h'2 three more timbers on one side of this hole broken2 inside oak planking rent off on a length of #ad'2 two iron bands torn up and bent1 one of them broken in two places2 outside planking torn off on a space of #ba' #ab'2 several planks still higher up broken4 ,no4 #b ,mine4--,timbers blown away on a space of about #h' square2 inside planking torn off on a length of #bj'2 two iron bands broken1 and torn up and bent2 and outside planking rent off on a space of #ai' #ab'4 ,no4 #c ,mine4--,timbers blown away on a space of #aj-a_/b' #ab' at one end1 and #f' at the other2 inside planking off for a length of #ad'2 one iron band torn up1 and one broken2 outside planking off on a space of #ah' #be' #ae'4 ,no4 #d ,mine4--,timbers blown away on a space #d' #af'2 on the sides of this hole1 ten timbers were broken2 two iron bands torn up1 and one broken2 inside planking off for a length of #bj'2 outside planking off for a space of #bj' #bc' #aj'1 and #ac feet4 ,no4 #e ,mine4--,the gas sphere of this mine had hit the middle of the outside plates on one of the angle-iron ribs4 ,this rib was torn from the timbers and bent up1 nearly #b' in the middle1 but not broken4 ,there was an oval hole in the outside plates #d' #c' between two ribs1 which ribs1 with the plates on edge riveted to them1 were bulged out about #e inches4 ,the inner plate1 one large piece was blown up in a vertical position1 after having cut all the bolts and rivets1 sixty of #a1 and thirty of #c_/d1 save those that fastened the lower side to the oaken frame and timbers4 ,on a length of #cj' and height of #bj'1 the bottom1 on all sides of the iron construction1 had been bent inwards2 the greatest bend was about #e2 three deck beams above had been broken4 ,by the joint effect of all the mines1 almost all the iron deck beam knees had been rent from the side1 and there was an opening between deck and hull on both sides for a length of about #acj feet4 ,experiment at ,kiel4--,target3--,a large gun-boat1 greatly strengthened internally by solid balks of timber4 ,torpedo3--#bjj lbs4 gunpowder4 ,it was placed nearly under her keel1 at a distance of #ae feet4 ,effect of explosion3--,complete destruction of the vessel4 ,experiment in ,england1 #ahgd4--,target3--,a rectangular iron case #bj' long1 #aj' high1 and #h' wide1 divided into six compartments by means of one longitudinal bulkhead midway between the front and rear faces of the target1 and two athwartship bulkheads equidistant from the ends of the target4 ,thickness of front and rear faces #aa_/af1 of longitudinal bulkhead #a_/d1 of athwartship bulkheads #c_/h4 ,torpedo3--#ajj lbs4 of gunpowder1 enclosed in a spar torpedo case and fired by two detonators4 ,it was exploded in contact with the target1 #g-a_/b' below the surface of the water1 and #g' from top of target4 ,effect of explosion on the target3--,front of centre compartment destroyed and top blown off4 ,plate representing inner skin destroyed4 ,back of centre compartment 7rear face of the target7 much bulged1 and penetrated2 the hole measured #cf' #ae4 ,large portions of the target were thrown to a height of #aej to #bjj feet1 and from #hj to #ajj yards' distance4 ,the effect of explosion on a ship's pinnace1 which had been placed #af feet from and at right angles to the front face of the target1 with steam up1 and canopy and shield in position1 was that a large quantity of water was thrown back in the boat1 putting the fires out1 and filling the boat up to her thwarts1 but otherwise the boat was uninjured4 ,experiments at ,copenhagen1 ,denmark1 in #ahgd4--,the object of these experiments was to ascertain if a ship's armoured side would be seriously injured by a torpedo exploded in contact with it4 #a,,st ,,experiment4 ,target3--#a thick1 and #b' #b'1 supported in a horizontal position on a substructure consisting of #h timber resting on two pieces of #f timber under two sides1 and completely supported by earth up to lower edge of substructure4 ,torpedo3--#cc lbs4 of dynamite1 enclosed in a square wooden case #b-a_/d high1 and #ee #ee2 it was placed on the middle of the earth with #h of earth tamping2 this tamping representing the resistance of a thin stratum of water4 ,effect of explosion3--,the plate was broken into four pieces1 and substructure crushed4 #b,,nd ,,experiment4 ,target3--#b thick1 and #b' #b-a_/b'1 supported in a horizontal position on a substructure as above1 but resting on four piles of #f x #f timber4 ,torpedo3--#hi lbs4 of dynamite1 enclosed in a wooden case #d high1 and #e #aj4 ,it was laid with one edge on the plate1 the other edge #c above the plate2 same tamping as above4 ,effect of explosion3--,the plate broken into three pieces1 and substructure crushed4 #c,,rd ,,experiment4 ,target3--#e thick1 and #c' #h #d' #g1 supported in a horizontal position on a substructure as above1 but eight piles of #f #f timber used4 ,plate bolted to the structure with eights4 ,torpedo3--#ddd lbs4 of dynamite1 enclosed in a wooden case1 of same thickness as the ,harvey torpedo1 and #d #ac #ba2 it was placed with surface against the plate1 one edge #b and the other #e-a_/b from the plate2 tamping as before4 ,effect of explosion3--,plate bulged #c-a_/d in the middle2 substructure completely crushed4 #d,,th ,,experiment4 ,target3--#e thick1 and #c' #h #d' #g2 this was the same plate as used in the previous experiment1 laid with bulge uppermost on two beams under the short sides4 ,torpedo3--#ddd lbs4 of dynamite1 enclosed in a cylindrical tin box #g-a_/b #b'2 it was placed on top of plate #aa from one side and with ends #i-a_/b from edge of plate2 tamping as before4 ,effect of explosion3--,a corner of the plate broken off4 #e,,th ,,experiment4 ,target3--,same plate placed vertically in the earth4 ,torpedo3--#ddd lbs4 of dynamite1 enclosed in a cylindrical tin box #he #ah2 it was placed on timber1 so as to rest against the face and centre of the plate2 tamping as usual4 ,effect of explosion3--,plate broken into four pieces1 two of which were large2 pieces hurled over parapet1 one fell at a distance of #djj feet4 ,experiments at ,carlscrona1 ,sweden1 in #ahgd-ge4--,these experiments were carried out by the ,swedish torpedo authorities1 to ascertain the effect of different sized charges of dynamite and gunpowder1 enclosed in divers cases1 and exploded at various distances from a target which represented in all respects1 with the exception of the armour1 a section of the side of ,h4,m4,s4 ,hercules before the boiler room1 she being at that time one of the most powerful vessels afloat4 ,target3--#cb' in length1 and fitted into the side of an old line of battle ship4 ,similar in shape to a wing tank1 and comprised a double bottom in four water-tight compartments1 a wing passage in two water-tight compartments1 and two large water-tight compartments in rear of all4 ,it extended from #b' above the water line to within about #e' of the vessel's keel4 ,the thickness of the plates forming the target were3--outer bottom1 lower portion #ac_/af2 part where torpedo took effect1 #c_/d4 ,inner bottom1 and wing passage bulkhead1 #a_/b4 ,vertical and longitudinal frames1 both solid and bracket1 #g_/af4 ,the longitudinal frames were bracket frames1 with the exception of the second1 which was solid and water-tight1 with its outer edge about #h' below the water line4 ,the vertical frames1 of which there were seven1 were placed #d' apart1 the central one being solid and water-tight1 the others being bracket frames4 ,the ship was moored in #db feet of water2 the charges were detonated1 one fuze being used in all but ,no4 #c experiment1 when five fuzes were employed4 #a,,st ,,experiment4 ,torpedo3--#cc lbs4 of dynamite1 enclosed in cylindrical steel case1 no air space2 height #ajge1 diameter #ajge1 and thickness #a_/cb4 ,it was placed #bee' from the target1 opposite ,no4 #g frame1 and #ibe' below the surface of the water4 ,effect of explosion3--,ship appeared to be lifted bodily4 ,a rivet in the midship longitudinal bulkhead of fore compartment was loosened4 ,the torpedo was fired from the ship1 and the shock felt was not very great4 #b,,nd ,,experiment4 ,torpedo3--#dgb lbs4 of dynamite1 in cylindrical steel case1 no air space2 height #ab1 diameter #ab1 and thickness #a_/cb4 ,it was placed #bee' from ,no4 #e frame1 #ibe' below the surface of the water4 ,effect of explosion3--,ship appeared to be lifted bodily4 ,a leak was started in the outer bottom opposite to charge1 caused by the loosening of five rivets4 #c,,rd ,,experiment4 ,torpedo3--#aab lbs4 of gunpowder1 rifle small grain1 enclosed in cylindrical steel case placed inside an iron case1 with an air space all round2 steel case1 #i-a_/b #bb-a_/b #a_/cb2 iron case #cc #be #a_/d4 ,it was placed #ab' from ,no4 #e frame1 #ibe' below the surface4 ,effect of explosion3--,centre of ship lifted bodily1 as if her back was broken2 ship then rolled heavily to port4 ,on board fire engines and troughs displaced several feet3 shores and struts started1 showing that the shock was considerable4 ,the outer bottom on each side of the centre dividing plate indented to a depth of #a to #a-a_/b inches2 numerous rivets started1 and some sheared4 ,the leak was considerable1 owing to the number of rivets that were started4 ,the strength of the plates was not considered to be materially affected by the indentations2 the rivets1 #bci in number1 were replaced2 and the target prepared for the next experiment4 #d,,th ,,experiment4 ,torpedo3--#cc lbs4 of dynamite1 enclosed as in first experiment4 ,it was placed #ae' from ,no4 #g frame1 #ibe' below the surface of the water4 ,effect of explosion3--,ship rolled slightly to port4 ,a bolt securing the midship transverse bulkhead to beam was sheared4 ,no damage done to the target4 #e,,th ,,experiment4 ,torpedo3--#ff lbs4 of dynamite1 enclosed in steel cylindrical case1 no air space1 #ace #ac #a_/cb4 ,it was placed #ba' from ,no4 #c frame1 #ibe' below the surface of the water4 ,effect of explosion3--,a rivet in outer bottom1 above water line at fore end of target1 was sheared4 ,a few rivets in outer bottom opposite charge1 and two in after compartment1 were started1 but no leak was perceptible4 ,several shores slightly displaced4 #f,,th ,,experiment4 ,torpedo3--#cc lbs4 of dynamite1 enclosed as in first experiment4 ,it was placed #abge' from ,no4 #g frame1 #ibe' below the surface of the water4 ,effect of explosion3--,ship not lifted as much as was the case in ,no4 #c experiment2 but explosion much sharper4 ,on board1 fire engines were capsized1 and vertical shores displaced4 ,outer bottom opposite charge indented to a depth of about #a_/b an inch1 other parts less bulged1 and many rivets started4 #g,,th ,,experiment4 ,torpedo3--#cc lbs4 of dynamite1 enclosed as in first experiment4 ,it was placed #d' from ,no4 #d frame1 #ibe' below the surface of the water4 ,effect of explosion3--,effect very great2 ship hurled suddenly to starboard4 ,on going on board two minutes after the explosion1 the fore compartment was found full1 the after compartment became full ten minutes later4 ,shores and struts were considerably displaced1 and there was evidence that the ship had sustained a severe shock4 ,outer bottom injured over an area #ad' #af'1 the plates being split in all directions2 one piece1 #e' square1 was torn completely off1 and an irregular hole was formed in the outer skin #ad' #ab'4 ,in the inner bottom below the wing passage bulkhead a piece #f' #i' was blown completely out2 the wing passage bulkhead was torn from the longitudinal frame and split from top to bottom4 ,the inner skin above the upper longitudinal frame was torn from the latter1 and forced in and upwards1 but was not otherwise damaged4 ,the vertical bracket frames ,nos4 #c and #d1 the latter opposite the torpedo1 were destroyed1 but the solid frame ,no4 #e was almost uninjured4 ,the outer bottom1 where it was not torn off1 was forced in #g'1 or #d' beyond where the inner bottom had been4 #h,,th ,,experiment4 ,torpedo3--#ffj lbs4 of gunpowder1 enclosed in a buoyant cylindrical #a_/d iron case4 ,it was placed #cbc' from ,no4 #d frame1 #bibe below the surface of the water4 ,effect of explosion3--,the ship and target had been thoroughly repaired1 and were in good condition when this experiment was made2 the ship was in this case moored in #fe feet of water4 ,no effect was produced on the target by the explosion4 #i,,th ,,experiment4 ,torpedo3--#ai lbs4 of dynamite1 enclosed in a cylindrical steel case with arched ends4 ,it was placed #aje' from ,no4 #c frame1 #ibe' below the surface of the water4 ,effect of explosion3--,effect produced apparently equal to that by ,no4 #c charge of #aab lbs4 of gunpowder at #ab'2 indentation being from #a_/b to #a-a_/d inches in the outer skin opposite the torpedo4 #aj,,th ,,experiment4 ,torpedo3--#ai lbs4 of dynamite1 enclosed in a case similar to that used in the #ith experiment4 ,it was placed #cc' from ,no4 #g frame1 #ibe' below the surface of the water4 ,effect of explosion3--,hole produced in outer skin1 #fe' #b' to #e'2 inner skin only bulged and slightly cracked in two places4 ,above the longitudinal frame1 a bulge was made in the outer skin #h' #g'1 with the above-mentioned hole2 below the longitudinal frame the indentation was #ad' #e' and #ba deep1 with two horizontal cracks #aj' x #ac'1 and several inches broad4 #aa,,th ,,experiment4 ,torpedo3--#aab lbs4 of gunpowder1 enclosed in a cylindrical case of #c_/fd steel1 placed in a #c_/af steel case1 with #bbc lbs4 of buoyancy4 ,ignition effected by a glass igniting bottle4 ,it was placed #ege' from ,no4 #e frame1 #ibe' below the surface of the water4 ,effect of explosion3--,there was but little upcast of water outside the ship1 but a great upcast through the ship4 ,she immediately lurched to starboard1 and on boarding her five minutes after1 the target was found full of water4 ,the effect on the target was as follows1 above the #bnd longitudinal frame1 where strengthened by the wing passage bulkhead3--,outer bottom blown away from the #dth to the #fth frames for a length of #h feet and a height of #d-a_/b feet1 and bent in #f-a_/b feet4 ,inner bottom bent in and broken through between the #dth and #eth frames1 with an irregular hole #h' square1 and between the #eth and #fth frames1 a similar sized hole4 ,wing passage bulkhead was bent in #b to #c1 and riven for a length of #bi'2 in the water-tight middle bulkhead athwartships the rivets in two vertical joints were completely torn away4 ,between the #bnd and #crd longitudinal frames1 and below the wing passage bulkhead1 both the inner and outer bottoms were completely blown away for a length of #ab feet and a height of #d feet4 ,the vertical and horizontal frames between the two bottoms had kept their position unchanged1 and excepting that the bracket plate by frame ,no4 #f was bent1 cracked1 and torn away1 the damage they had sustained was limited to some comparatively slight bending4 ,the open hole formed in the target measured #gf square feet in outer bottom1 and #fj square feet in inner bottom4 ,comparing the effect of this torpedo with the #gth1 #cc lbs4 of dynamite2 with the latter charge the breach was made at the cost of the bottom plates as well as the vertical and longitudinal frames1 which were completely torn asunder and strained2 with the gunpowder charge1 only the bottom plates were broken through1 whilst the plates whose directions were nearly parallel to the lines of explosive effect were but little affected4 ,experiments at ,portsmouth1 ,england1 #ahgd-ge4--,the object of these experiments was to ascertain the effect of #ejj lbs4 gun-cotton torpedoes exploded at various distances from a target representing the double bottom of ,h4,m4,s4 ,hercules4 ,they were carried out in ,stokes ,bay1 under the supervision of officers belonging to the torpedo department of the ,royal ,engineers1 and a torpedo committee1 composed of naval and military officers4 ,the ,oberon1 the vessel chosen for these experiments1 was fitted with a double bottom1 representing as nearly as possible that of the ,hercules without the armour2 also with a surface condenser1 and its connections2 a donkey ,kingston feed-valve2 and athwartship water-tight bulkheads1 which divided the ship into seven water-tight compartments4 ,the outer skin was composed of #c_/af and #g_/h iron plates4 ,in her starboard side at different points were fixed forty-four crusher gauges1 and over each side were suspended six shots1 each fitted with a crusher gauge4 ,displacement of the ,oberon about #aajj tons4 ,the ship was anchored head and stern4 ,her mean draught of water during the experiments was #aa feet4 #a,,st ,,experiment4 ,torpedo3--#ejj lbs4 of gun-cotton1 in discs saturated with water1 and enclosed in an iron cylindrical case1 #cd #cj #a_/d1 with arched ends2 the primer consisted of two dry discs1 and two detonators4 ,it was placed #aja' horizontal from the target1 and opposite the condenser on the starboard side2 #dg' below the surface of the water1 on the ground4 ,effect of explosion3--,no damage was done to the hull1 or condenser1 but light articles1 such as bunker plates1 gratings1 tank lids1 c41 were displaced4 #b,,nd ,,experiment4 ,torpedo3--,as in first experiment4 ,it was placed on the ground1 #hj' horizontal and opposite the condenser on the starboard side1 #dh' below the surface of the water4 ,effect of explosion3--,no damage was done to the hull1 of condenser1 but the bunker plates1 gratings1 c41 were displaced to a greater extent than in the previous experiment4 #c,,rd ,,experiment4 ,torpedo3--,as before4 ,it was placed on the ground1 #fj' horizontal1 and opposite the condenser on the starboard side2 #dg' below the surface of the water4 ,effect of explosion3--,no damage was done to the hull4 ,flanges of the condenser inlet pipe were cracked1 and several of the joint bolts were broken4 ,the condenser had been thrown up bodily1 and had torn away its holding down bolts2 but it was not as well secured as it would have been had it formed part of the machinery of a ship4 #d,,th ,,experiment4 ,torpedo3--,as before4 ,it was placed on the ground1 #ej' horizontal1 and opposite the condenser on the starboard side2 #dh' below the surface of the water4 ,effect of explosion3--,outer bottom on starboard indented over a length of about #ajj'1 being forced in between the frames2 maximum indentation1 #c_/d4 ,many bracket frames were disturbed1 and outer angle iron of water-tight longitudinal was started for a length of #cj'1 and made to leak slightly4 ,the shell of the condenser was cracked in two places1 #c' and #e' in length4 ,bolts securing condenser1 and flanges of pipes and valves1 were all more or less damaged4 ,condenser was rendered unserviceable4 #e,,th ,,experiment4 ,torpedo3--,same charge as before1 but the primer consisted of four dry discs1 and two detonators4 ,it was placed #bhe' horizontal1 opposite ,no4 #i frame1 on the starboard side1 #cf' from the stern2 #dh' below the surface of the water1 and #bb' from the ground4 ,effect of explosion3--,bow observed to be lifted several feet4 ,several angle irons and bracket frames were cracked1 and numerous rivets in outer bottom were broken off4 ,the outer bottom on the starboard side was indented between the frames1 and brackets were disturbed over a space of #ajj feet2 inner bottom uninjured4 #f,,th ,,experiment4 ,torpedo3--,as in previous experiment4 ,it was placed on the ground1 #bhe' horizontal1 opposite ,no4 #cf frame on the starboard side1 and #cj feet from the stern2 #die' below the surface of the water4 ,effect of explosion3--,several plates in the outer bottom were cracked1 and outer bottom made to leak in several places1 owing to the fractures in the plates1 rivets being started1 and seams being opened4 ,considerably more damage was effected than in previous experiment1 but inner bottom still remained uninjured4 #g,,th ,,experiment4 ,torpedo3--,as in the #eth experiment4 ,it was placed on the ground1 immediately under the edge of the outer bottom1 #ci-c_/d' from the target1 and opposite ,no4 #ah frame1 #gj' from the stern2 #ej' below the surface of the water4 ,effect of explosion3--,outer and inner bottom broken entirely asunder at ,no4 #ai frame on the starboard side1 and between ,nos4 #af and #ag on the portside4 ,a fracture was caused in the outer bottom extending from the shelf plate to upper edge of strake next the keel on the starboard side1 and from the shelf plate to upper edge of flat keel plate on the port side4 ,a fracture was also caused in the inner skin extending from the topside to the outer edge of the garboard strake on the starboard side1 and from the topside to upper edge of garboard strake on the port side2 this including a fracture of the keel at ,no4 #ag4 ,the vertical keel1 the longitudinals1 as well as numerous bracket plates and angle irons1 were broken1 and about #bjjj rivets in the outer bottom were rendered defective4 ,the outer bottom was indented over a considerable length1 the indentation being greatest between the frames1 and the maximum being #h inches4 ,the inner bottom was not indented or damaged1 with the exception of the fractures before mentioned4 ,experiments at ,pola1 ,austria1 #ahge4--,these experiments were carried out to determine the effect of very heavy charges of dynamite on an iron pontoon fitted with a double bottom1 similar to that of ,h4,m4,s4 ,hercules4 ,target3--,an iron pontoon #fj' long and #dj' beam1 with circular ends and fitted with a double bottom1 also a condenser and two ,kingston valves4 #a,,st ,,experiment4 ,torpedo3--#fag lbs4 of dynamite4 ,it was #fb' horizontally from the keel1 #ec' actual distance from the side1 and opposite amidships1 #dje' below the surface of the water1 and #bj' from the ground4 ,pontoon3--,draught of water #ai'1 and moored in #fb' of water4 ,effect of explosion3--,the pontoon moved away bodily a distance of #ac feet2 a few rivets in the outer bottom were started1 and the outer skin was slightly indented between the frames2 the maximum indentation being #ae4 ,no other damage was sustained by the hull4 ,several of the screws securing the flanges of the ,kingston valves were slightly loosened4 #b,,nd ,,experiment4 ,torpedo3--#ehe lbs4 of dynamite4 ,it was placed #fj' horizontally from the keel1 #dh' actual distance from the side1 and opposite amidships2 #cf' below the surface of the water1 and #db' from the ground4 ,pontoon3--,draught of water #aie'1 and moored in #gd' of water4 ,effect of explosion3--,the pontoon1 which had been more rigidly moored than in the previous experiment1 was moved bodily away a distance of #d feet4 ,many rivets were loosened1 and a few connecting the angle irons were sheared2 also the outer skin was slightly indented4 ,no damage was done to the condenser or ,kingston valves4 ,experiment in the ,sea of ,marmora1 #ahge4--,this experiment was carried out by ,turkish officers attached to their naval school at ,halki1 an island in the ,sea of ,marmora1 about eight miles from ,stamboul4 ,it consisted in destroying a ,turkish schooner by the explosion of an #ajj-lb4 gun-cotton mine in contact with her1 moored in #eh feet of water1 and #aj feet beneath the surface4 ,experiment at ,carlscrona1 ,sweden1 #ahgf4--,this experiment was a continuation of those previously carried out in #ahgd-ge1 and which have been detailed at page #bbd1 c4 ,target3--,the same as had been used for the previous experiments 7#ahgd-ge71 and which had been thoroughly repaired4 ,,experiment4 ,torpedo3--#ffj lbs4 of gunpowder1 enclosed in a buoyant cylindrical #a_/d steel case with domed ends1 and contained in an inner #a_/af steel case4 ,it was ignited by two ,von ,ebner fuzes placed in a charge of #a_/d lb4 of gunpowder and enclosed in a glass bottle4 ,it was placed #e' horizontally from the water line1 #bcge' actual distance from target1 and opposite ,no4 #e 7middle7 frame of target1 #bi' below the surface of the water4 ,effect of explosion3--,the ship was moored in #ed' of water4 ,she was lifted by the explosion1 rolled over to port1 and then settled to starboard1 sundry large pieces of timber being thrown up in the air4 ,the outer bottom of the target was broken through above the second longitudinal frame1 from the fourth to the seventh frames laterally1 and from the top of the target to the second longitudinal frame vertically1 the hole made measuring about #i' high by #ab' wide1 or about #ajj square feet in area4 ,the inner bottom was also broken through between the top of the target and second longitudinal frame1 and between the fourth and seventh vertical frames1 the hole made being about #ge square feet in area4 ,the bracket frames within the damaged area were but little damaged4 ,the wing passage bulkhead was broken through opposite to ,nos4 #e and #g frames1 the holes made being respectively #ah and #ag square feet in area4 ,through these holes the force of the explosion had made its way to the horizontal iron deck1 forming the top of the target1 which was completely broken through a little abaft ,no4 #e frame1 the hole made measuring about #ajj square feet in area4 ,a piece of this iron deck1 weighing1 with the iron fastenings attached to it1 about #afej lbs41 was thrown #af' against the upper deck beams4 ,the target below the second longitudinal frame was comparatively but little injured4 ,the outer bottom was indented and cracked in one or two places1 but the inner bottom was uninjured4 ,in addition to the damage to the target1 the ship herself sustained serious injury1 eleven of the lower deck beams1 with their knees being broken 7six being broken completely across74 ,the main keel immediately under the target was also opened at the scarf1 and the back of the ship was apparently broken4 ,the hull had given out laterally to such an extent as to prevent the ship being taken into dock4 ,experiments at ,portsmouth1 ,england1 #ahgf4--,the object of the following experiments was to determine the effect of comparatively small charges of gunpowder and gun-cotton exploded in actual contact with an ironclad1 as would be the case in a torpedo attack either with locomotive towing or spar torpedoes4 ,target3--the same as used in the experiments of #ahgd-e1 which have been detailed at page #bbi1 c41 viz41 the ,oberon fitted to represent ,h4,m4,s4 ,hercules without the armour4 ,her mean draught was #aa'1 and she was moored in #bf-a_/b' of water4 ,the ,oberon had been placed in a thorough state of repair4 #a,,st ,,experiment4 ,torpedo3--#fj lbs4 of gun-cotton in slabs1 saturated with water4 ,total weight of charge #ge lbs4 ,it was enclosed in a #a_/d iron case with cast iron ends4 ,it was placed at #ae' actual distance from the nearest side of the case to the target1 and opposite ,no4 #d frame on the port side1 #aj' below the surface of the water4 ,effect of the explosion3--,the effect upon the vessel was unappreciable4 ,this charge represented the large ,whitehead fish torpedo1 and its position corresponded to that of this torpedo when striking a net at a small angle with the keel4 #b,,nd ,,experiment4 ,torpedo3--,the ,harvey towing torpedo1 charged with #ff lbs4 of gunpowder1 primed with gunpowder1 and fired by means of an electric fuze4 ,it was placed at #c' actual distance from the target1 measuring from the centre of the torpedo1 and opposite ,no4 #d solid frame on the starboard side1 the vertical axis of the torpedo being at right angles to the vessel's side1 #i-a_/d' below the surface of the water4 ,effect of explosion3--,this and the two following torpedoes were fired simultaneously4 ,the outer bottom was blown in from the upper edge of the flat keel plate to the underside of the water-tight longitudinal1 and fore and aft from ,no4 #b to ,no4 #f frames2 an area #af' #h-e_/f'4 ,flat keel plates were broken between ,no4 #b and ,no4 #d frames1 and the #dth strake of the bottom plating was broken1 and the frames for that space blown in4 ,two holes were blown through the inner bottom1 measuring respectively #b' #b' and #g' #a'1 making the total area of the inner bottom destroyed1 #aa square feet4 #c,,rd ,,experiment4 ,torpedo3--#cc lbs4 of granulated gun-cotton1 saturated with water2 total weight of charge being about #da lbs4 ,it was enclosed in a #a_/d iron case1 #ab-a_/b #ab #ab-a_/b1 the primer being #b-a_/b lbs4 of slab gun-cotton1 included in the #cc lbs4 ,it was placed at #d' actual distance from the target1 measuring from the centre of the case1 and opposite ,no4 #cj-a_/b solid frame on the starboard side2 #i-a_/d' below the surface of the water4 ,effect of explosion3--,outer bottom blown in from upper edge of the lower longitudinal to the lower edge of the upper longitudinal between ,nos4 #bh and #cb frames2 an area of #ah #aa feet4 ,the butts of the flat keel were started and the plating broken across ,no4 #cj-a_/b frame from the flat keel plate to the upper deck4 ,shelf plate at ,nos4 #cj-a_/b and #cb-a_/b frames was broken4 ,nos4 #bi1 #cj1 and #ca frames were blown in from first to third longitudinal2 lower longitudinal from ,no4 #bh to #ca also blown in4 ,two holes were blown through the inner bottom1 measuring respectively #f #ae' and #e' #be'1 making the total area of inner bottom destroyed #aj square feet4 ,a steam launch with steam up and outrigger torpedo gear in place1 one pole being rigged out1 was placed with the stem of the boat #bb' horizontally from the torpedo4 ,she was uninjured and shipped very little water4 #d,,th ,,experiment4 ,torpedo3--#ca lbs4 #ad oz4 of gun-cotton in slabs1 saturated with water1 total weight about #dj lbs4 ,it was enclosed in a #a_/d iron case #ab-a_/b #ab-a_/b #f2 primer being #bj oz4 of gun-cotton1 included in the #ca lbs4 #ad oz4 ,it was placed at #d' actual distance from the target measuring from the centre of the case1 and opposite ,no4 #cj-a_/b solid frame on the port side2 #i-a_/d' below the surface of the water4 ,effect of explosion3--,outer bottom and frames injured in a similar manner to that described in the third experiment4 ,outer angle irons of the #ast1 #bnd1 and #crd longitudinals were started in the wake of the broken place4 ,a hole was blown through the inner bottom1 measuring #ie' #a'1 or about #aj square feet in area4 ,the bolts of the outer bottom plate of stern post much open1 and at ,nos4 #af and #ag on the port side the upper two strakes were buckled and the shelf plate started4 ,a steam launch1 arranged in the same manner as in the fourth experiment1 was uninjured1 and shipped but little water4 ,experiments with ,countermine4--,the following experiments have been carried out in ,england and other countries to ascertain some reliable data for countermining operations4 #a,,st ,,experiment4 ,experiments in the ,medway1 ,england1 #ahgj4--;,countermine3--#dcb lbs4 of compressed gun-cotton1 enclosed in a #c_/af iron case4 ,it was moored at a depth of #cg' below the surface of the water4 ,submarine mines3--,a series of similar cases containing coal dust1 c41 were moored at distances of #ej' to #ajj' from the countermine1 and #cg feet below the surface4 ,effect of explosion3--,the submarine mine at #hj' distance was completely destroyed2 the dome of its circuit closer was dented in4 #b,,nd ,,experiment4 ,countermine3--,as before1 but moored #bg' below the surface4 ,submarine mines3--,as before1 but moored at distances of #gj' to #abj' from the countermine1 and #bg' below the surface4 ,effect of explosion3--,the submarine mine case at #abj' distance was dented1 but remained water-tight2 the copper guard of fuze piece collapsed1 and the earth connection of the fuzes was ruptured2 the dome of its circuit closer was dented4 #c,,rd ,,experiment4 ,countermine3--,as before1 but moored #dg' below the surface4 ,submarine mines3--,as before1 but moored at distances of #gj' to #bjj' from the countermine4 ,effect of explosion3--,the submarine mine case at #bjj' distance was dented1 but it did not leak4 #a,,st ,,experiment4 ,experiments at ,stokes ,bay1 ,england1 #ahgc4--;,countermine3--#ejj lbs4 of gun-cotton1 enclosed in a #c_/af iron case4 ,it was placed on the ground1 in #dg' of water4 ,submarine mines3--,six ground mines1 #a_/d thick cases1 fitted with circuit1 #aj' below the surface1 at distances of #ajj' to #bjj' from the countermine4 ,effect of explosion3--,submarine mines at #ajj' and #abj' distance were destroyed1 and their circuit closers thrown out of adjustment2 submarine mines at #adj' and #agj' distance were much bulged1 and leaked1 and their circuit closer spindles were bent2 submarine mine at #bjj' distance was uninjured1 but its circuit closer was thrown out of adjustment4 #b,,nd ,,experiment4 ,countermine3--#ajj lbs4 of gun-cotton enclosed in case1 thickness ,no4 #ab ,b4 ,w4 ,g4 ,it was moored #aj' below the surface1 in #ce' of water4 ,submarine mines3--,five similar mines placed at same depth1 at distances of #ej' to #aej' from the countermine4 ,effect of explosion3--,the submarine mine at #ej' distance showed continued or dead earth1 two screws broken1 and its case dented2 the other mines were uninjured4 #a,,st ,,experiment4 ,experiments at ,carlscrona1 ,sweden1 #ahgd4--;,countermines3--#bbf lbs4 of dynamite1 enclosed in a case #ag-a_/b #bj #a_/h4 ,it was moored #i-c_/d' below the surface1 the depth of water being #da feet4 ,submarine mines3--7a7 cast iron ground #fjj lb4 mines1 dome shaped1 #dh-c_/d #ba-a_/b #b2 7b7 cylindrical cases1 wrought iron1 empty1 #aa-a_/b #aa-a_/b #a_/h2 7c7 cylindrical cases1 wrought iron1 charged1 #aa-a_/b #aa-a_/b #a_/h2 7d7 cylindrical cases1 wrought iron1 #cj-a_/d #cj-a_/d #a_/h2 7e7 spherical cases1 wrought iron1 #cb-a_/b #a_/h2 7f7 spherical cases1 tinned steel1 #ab #a_/h4 ,effect of explosion3--7b7 mine1 at #cd' distance1 was destroyed1 and one at #ib' distance was slightly bulged2 7c7 mine1 #eh' distance1 mouthpiece injured and case leaky2 7d7 mine1 #bdd' distance1 a rivet started4 #b,,nd ,,experiment4 ,countermine3--,as before1 but moored at #bi-a_/d' below the surface2 depth of water1 #da feet4 ,submarine mines3--,as before4 ,effect of explosion3--7a7 mine1 at #adf' distance1 split in two2 7b7 mine1 #cd' distance1 destroyed2 at #di' distance1 fractured2 at #fh' distance1 indented but not fractured2 7c7 mine1 #eh' distance1 case much bulged1 and leaky2 7d7 mine1 at #bdd' distance1 rivets started1 case half full of water2 at #aie' distance1 sunk1 several rivets started2 7e7 mine1 at #aie' distance1 bolt loosened2 7f7 mine1 at #fh' distance1 not injured4 #c,,rd ,,experiment4 ,countermine3--#dec lbs4 of dynamite1 enclosed in a case1 #bd-a_/b #bh-a_/d #a_/h4 ,it was moored #i-c_/d' below the surface2 depth of water as before4 ,submarine mines3--,as before4 ,effect of explosion3--7b7 mine1 at #di' distance1 sunk and not recovered2 at #eh' distance1 very much indented2 7c7 mine1 at #eh' distance1 case much indented and leaky2 7f7 mine1 at #dh-a_/b' distance1 uninjured4 #d,,th ,,experiment4 ,countermine3--,as before1 but moored #bi-a_/d' below the surface4 ,effect of explosion3--7a7 mine1 at #aie' distance1 completely stove in2 7c7 mine1 at #eh' distance1 case indented but charge dry2 7e7 mine1 at #age' distance1 slightly leaky2 7f7 mine1 at #dh-a_/b' distance1 upper half indented in three places4 ,it was also discovered during the above experiments that submarine mines charged with dynamite can be caused to explode by the detonation of a charge of the same explosive1 at distances from it considerably beyond those at which the cases themselves are damaged by a similar charge4 ,to prevent the foregoing1 it is necessary to pack the dynamite very carefully1 using at the same time special precautions4 ,,chapter ,x4 ,,the ,,electric ,,light--,,torpedo ,,guns--,,diving4 ,,electric lights combined with fast steam launches as guard boats and specially constructed torpedo guns1 such as the ,nordenfelt and ,hotchkiss machine guns1 are at the present time the only truly practicable means afforded to a man-of-war of defending herself against the attack of torpedo boats1 whether these latter are armed with the spar1 fish1 or towing torpedo2 the torpedo gun sinking the boats after the electric light and guard boats have detected their approach and position4 ,as has been before stated1 nets1 shields1 booms1 c41 placed around a vessel of war1 must1 however slightly constructed1 affect to a considerable degree her efficiency1 by decreasing her power of moving quickly in any desired direction1 which is essential to the utility of such a vessel in time of war2 and thus on electric lights1 guard boats1 and torpedo guns must the safety of ships in future wars really depend1 when attacked by torpedo boats4 ,the ,electric ,light4--,the phenomenon of the ,voltaic arc was first discovered by ,sir ,humphry1 then ,mr41 ,davy at the beginning of the present century4 ,the following is an account of the matter as given by him in his ,elements of ,chemical ,philosophy3-- ,the most powerful combination that exists1 in which number of alternations is combined with extent of surface1 is that constructed by the subscription of a few zealous cultivators and patrons of science in the laboratory of the ,royal ,institution4 ,it consists of #bjj instruments1 connected together in regular order1 each composed of ten double plates arranged in cells of porcelain1 and containing in each plate thirty-two square inches2 so that the whole number of double plates is #b1jjj1 and the whole surface #abh1jjj square inches4 ,this battery1 when the cells were filled with sixty parts of water1 mixed with one part of nitric acid1 and one part of sulphuric acid1 afforded a series of brilliant and impressive effects4 ,when pieces of charcoal about an inch long and one-sixth of an inch in diameter were brought near each other 7within the thirtieth or fortieth part of an inch71 a bright spark was produced1 and more than half the volume of the charcoal became ignited to whiteness1 and by withdrawing the points from each other1 a constant discharge took place through the heated air1 in a space equal at least to four inches2 producing a most brilliant ascending arch of light1 broad1 and conical in form in the middle4 ,when any substance was introduced into this arch1 it instantly became ignited4 ,platina melted as readily in it as wax in the flame of a common candle2 quartz1 the sapphire1 magnesia1 lime1 all entered into fusion2 fragments of diamond1 and points of charcoal and plumbago1 rapidly disappeared1 and seemed to evaporate in it1 even when the connection was made in a receiver exhausted by the air pump2 but there was no evidence of their having previously undergone fusion4 ,the philosopher also showed that1 when the ,voltaic or electric arc is produced in the exhausted receiver of an air pump1 the phenomena are as brilliant in character1 and the charcoal points can be more widely separated1 thus proving that the electric light is quite independent of the oxygen of the air for its support4 ,owing to the crude nature of the ,voltaic batteries of that day1 and also to the great expense of maintaining a large battery of that nature1 nothing practical resulted from ,davy's discovery of the electric or ,voltaic arc4 ,professor ,faraday1 the great physicist1 by his discovery of the principle of magneto-electricity1 has enabled the electric light to be brought into practical use4 ,as early as #ahcc ,pixii applied the principle practically in the construction of a magneto-electric machine with revolving magnets2 he was followed by ,laxton1 ,clark1 ,nollet1 ,holmes1 and others1 who made machines with fixed magnets4 ,in #ahed ,dr4 ,werner ,siemens1 of ,berlin1 introduced the ,siemens' ,armature1 which1 from its compact form1 permitted a very high velocity of rotation in an intense magnetic field1 giving powerful alternating currents1 which1 when required1 were commutated into one direction4 ,the latest improvement has been that from the magneto-electric to the dynamo-electric machine4 ,it is due to both ,dr4 ,siemens and ,sir ,c4 ,wheatstone4 ,induced currents are directed through the coils of the electro-magnets which produce them1 increasing their magnetic intensity1 which in its turn strengthens the induced currents1 and so on1 accumulating by mutual action until a limit is reached4 ,siemens' ,electric ,light4--,the following is a description of ,messrs4 ,siemens ,brothers' dynamo-electric light apparatus1 which1 for use on board ship against boat torpedo attacks1 c41 is equal1 if not superior1 to any similar apparatus yet produced1 and which is extensively used in the ,german and other ,european navies4 ,this apparatus was one of many others experimented on by ,dr4 ,tyndal and ,mr4 ,douglas1 ,m4,i4,c4,e41 for the ,trinity ,house4 ,dr4 ,tyndal says3 ,i entirely concur in the recommendation of ,mr4 ,douglas1 that the ,siemens machine recently tried at the ,south ,foreland be adopted for the ,lizard4 ,from the first ,i regarded the performance of this handy little instrument as wonderful4 ,it is simple in principle1 and so moderate in cost that a reserve of power can always be maintained without much outlay4 ,by coupling two such machines together1 a great augmentation of the light is moreover obtainable4 ,principle4--,when a closed electrical circuit is moved in the neighbourhood of a magnetic pole1 so as to cut the lines of magnetic force1 a current is generated in the circuit1 the direction of which depends upon whether the magnetic pole is ,n or ,s2 it also depends on the direction of motion of the circuit1 and according to the law of ,lenz1 the current generated is always such as to oppose the motion of the closed circuit4 ,all magneto-electric and dynamo-electric machines are based on the principle stated above1 and are subject to many modifications4 ,the name dynamo-electric machine is given to it1 because the electric current is not induced by a permanent magnet1 but is accumulated by the mutual action of electro-magnets and a revolving wire cylinder or armature4 ,it is found that1 as the dynamic force required to drive the machine increases1 so also does the electric current2 it is therefore called a dynamo-electric machine4 ,description4--,in the machine here described1 of which ,fig4 #afd is an elevation1 ,fig4 #agc a part elevation1 and ,fig4 #afe a longitudinal section1 the electric current is produced by the rotation of an insulated conductor of copper wire or armature coiled in several lengths1 #h1 #ab1 #af1 c41 up to #bh1 and in several layers1 longitudinally1 upon a cylinder with a stationary iron core nn' ss'1 so that the whole surface of the armature is covered with longitudinal wires and closed at both ends1 as in ,fig4 #afe4 ,this revolving armature is enclosed to the extent of two-thirds of its cylindrical surface by curved soft iron bars ,,nn#a1 ,,ss#a4 ,illustration3 ,fig4 #afd4 ,the curved bars are the prolongations of the cores of the electro-magnets ,e ,e ,e ,e4 ,they are held firmly together by screws to the sides or bottom of the cast iron frame of the machine1 making it compact and strong4 ,the coils of the electro-magnet form with the wires of the revolving armature one continuous electric circuit1 and1 when the armature is caused to rotate1 an electric current 7which at first is very feeble7 is induced by the remanent magnetism in the soft iron bars and directed through the collecting brushes into the electro-magnet coils1 thus strengthening the magnetism of the iron bars1,v which again induce a still more powerful current in the revolving armature4 ,the electric current thus becomes stronger and stronger1 and the armature therefore revolves in a magnetic field of the highest intensity1 the limit of which is governed by the limit of saturation of the soft iron4 ,at each revolution the maximum magnetic effect upon each convolution of the armature is produced just after it passes through the middle of both magnetic fields1 which are in a vertical plane passing through the axis of the machine 7i4 e4 ,n#a,s#a in ,fig4 #agc74 ,the minimum effect is produced when in a plane at right angles to it1 i4 e4 horizontal4 ,illustration3 ,fig4 #afe4 ,according to the law of ,lenz already referred to1 when a circuit starts from a neutral position on one side of an axis towards the pole of a magnet1 it has a direct current induced in it1 and the other part of the circuit which approaches the opposite pole of the magnet has an inverse current induced in it2 these two induced currents are1 however1 in the same direction as regards circuit4 ,a similar current will also be induced in all the convolutions of wire in succession as they approach the poles of the magnets4 ,these currents1 almost as soon as they are induced1 are collected by terminal rollers or brushes ,b1 usually the latter1 placed in contact with the commutator in the position which gives the strongest current4 ,the position giving the strongest current gives also the least spark1 so that when there are no sparks at the commutator the best lighting effect is produced4 ,fig4 #aff shows position of brushes when the armature revolves in the direction indicated by the arrow4 ,the circumference of the revolving armature is divided into an even number of equal parts1 each opposite pair being filled with convolutions of insulated wire wound parallel to the axis of the armature4 ,the ends of these wires are brought to a commutator and connected to the segments either by screws or by soldering4 ,the brushes collect the electric currents as they are induced1 which is nearly constant and continuous4 ,the collecting brushes are combs of copper wire placed tangentially to the cylindrical commutator1 and press lightly upon it with an elastic pressure4 ,illustration3 ,fig4 #aff4 ,power and ,light produced4--,an increase of the armature speed produces a corresponding increase in the current produced1 but not in the same proportion4 ,the current increases more rapidly than the speed1 and could be made to reach any intensity but for considerations explained below4 ,with increase of current there is also increase of heat4 ,the speed for continuous work must not be taken too high1 because the heat developed at high velocities might destroy the insulation of the coils of the electro-magnet4 ,the speed given for this machine produces no such injurious heating effect4 ,the strength of the current is also influenced by the resistance of the electric lamp and its leading wires4 ,with an electric lamp in a circuit of proper resistance the armature should revolve at the rate given in the following ,table4 ,the heating will then reach its maximum1 which is very moderate1 in about three hours after which there will be no further change4 ---------------------------------------- -------------------------- ,,table4 ---------------------------------------- ----------------------- ,size4 ,number of revolutions,intensity of light in,,hp 7actual7 to of armature4 standard candles4 drive4 ---------------------------------------- ----------------------- ,medium #hjj to #hej #d1jjj to #f1jjj #c-a_/b to #d ---------------------------------------- ----------------------- ,the intensity of the unassisted light is given in standard candles4 ,the standard here used is a stearine candle consuming #aj grammes per hour4 ,regulation4--,from the fact that a closed circuit rotating in a magnetic field experiences resistance to its motion which a broken circuit does not1 motive power to any extent is only required when the circuit is closed4 ,an interruption of the current is therefore equivalent to removing the load from the motor1 which for mechanical reasons may be injurious to it and for electrical reasons to the dynamo machine4 ,the sudden interruption of the circuit of the large machine produces an electric tension so dangerously high as to strain or destroy the insulation of the machine4 ,when contact is again made after such interruption1 the increase of speed resulting from the interruption causes a momentary current of great intensity1 accompanied by sparks at the commutator4 ,in order that the light may be quite steady the speed should be as uniform as possible4 ,as too high an increase of speed may result in temporary extinction of the light1 it ought never to be permitted4 ,the motor should therefore be provided with a good and sensitive governor1 that will keep the speed perfectly uniform however the steam and load may vary4 ,a large and heavy fly-wheel is also very useful in keeping the speed nearly uniform during change of load4 ,although the circuit1 when the machine is in full action1 should never be suddenly interrupted1 interruption arising from the extinction of the light is not dangerous1 because it is always preceded by a decrease in the strength of the current4 ,when it is desired to divert the current into another circuit it is advisable to stop the machine4 ,although in practice with small machines this is rarely done1 with large machines it is necessary4 ,self-acting ,shunt4--,for great security1 especially with the two machines coupled together1 where the electric current is strong and the light equivalent to about #ad1jjj candles1 it is advisable to insert in the circuit a self-acting shunt4 ,illustration3 ,fig4 #afg4 ,this is placed between the lamp and machine and connected to both leading wires4 ,its principle is as follows3-- ,the terminal ,m1 ,fig4 #afg1 is joined by a short connecting wire to one terminal of the machine4 ,the terminal ,l ,m is connected to the remaining terminal of the machine and also to one of the lamp terminals4 ,the terminal ,l is connected to the other terminal of the lamp4 ,the shunt contains a small electro-magnet ,e mounted upon a square wooden slab or baseboard with its armature a1 a contact c1 and1 below the slab1 a resistance coil ,w1 which is equal to the resistance of the electric arc of the light1 about #a ,s4 u4,w ,as long as the lamp is burning well1 the current circulates in the coils of the electro-magnet1 and the armature a being strongly attracted1 there is no contact at c4 ,the resistance coil ,w is therefore not in electrical circuit4 ,when the light is extinguished the current in the coils of the electro-magnet ceases1 and the armature is withdrawn by the spring f making contact at c4 ,this offers to the electric current a path through ,w of equal resistance to that of the lamp1 and the current is subjected to scarcely any change1 so that the motor has practically no cause to alter its rate4 ,when the carbon points of the lamp again touch1 the electric current returns to them1 breaking contact at c1 re-establishing the former conditions4 ,direction of ,rotation4--,the armature may revolve in either direction4 ,if it becomes necessary to drive it in the opposite direction to that for which the machine has been made1 it is only necessary to reverse the brushes1 placing their points in the direction of motion1 and to change two of the wire connections1 which operations can be effected in a few minutes4 ,fig4 #aff shows the position of brushes for one direction of rotation and ,fig4 #afh that for the other4 ,illustration3 ,fig4 #afh4 ,conducting or ,leading ,wires4--,the leading wires are usually of copper of high electrical conductivity4 ,they must be insulated from one another the whole of their length and not placed too close together4 ,as their resistance affects the intensity of the light very much1 the section must be carefully proportioned to the distance of the lamp from the machine4 ,the best practical result is obtained when their resistance together with that of the lamp is equal to the total internal resistance of the dynamo machine4 ,wires of various sizes are therefore required4 ,decrease in strength of the current caused by a leading wire of too high resistance can be overcome by a higher velocity1 which is obtained only by increased motive power1 but if the wire is much too small1 it will become heated4 ,the proper remedy is to increase the sectional area of the leading wire4 ,bright sparks should never be allowed to appear at the commutator and brushes1 as sparks result from a rapid burning of the metallic parts4 ,they can easily be avoided by properly inclining the two arms which carry the brushes4 ,the position of the brushes yielding the least spark at the commutator is that giving the highest intensity of light in the electric arc4 ,the commutator should1 while in motion1 be freely oiled1 to prevent the brushes wearing away too rapidly4 ,the sticky oil should from time to time be removed by washing with paraffine oil or benzoline4 ,wear and ,tear4--,the chances of stoppage so common to the old forms of electric light apparatus have in this form been reduced to a minimum1 and now do not exceed those that arise with machines generally4 ,the ,trinity ,house ,report states that the ,siemens' machine worked well for a month without any necessity for stopping4 ,the brushes are the only parts which wear away1 and they are very easily replaced4 ,in thick weather they should be connected in what is called parallel circuit 7or parallel arc1 or for quantity71 because it has been found that when they are so arranged the intensity of the electric light produced exceeds by some twenty per cent4 the intensity of the sum of the two when worked separately4 ,thus the two machines1 giving respectively a candle power of #d1ddf and #f1efc when worked separately 7total #aa1jji71 have given when coupled up in parallel circuit a light equivalent to #ac1agi candles2 just as in telegraphy it has been found that the rate of sending can be increased from #bj to #be per cent4 when the apparatus is coupled up in parallel arc4 ,for this reason it is usual to employ two machines of medium size instead of one machine of large size4 ,the intense light so produced is also much more uniform than from one large machine4 ,automatic ,electric ,lamp4--,automatic electric lamps have been constructed with spring clockwork to cause the carbons to approach one another to a certain point1 when1 by means of an electro-magnet1 the clockwork is checked1 and the carbon points are allowed to burn away to such a distance that1 by the decrease of current1 the clockwork is released and the carbons caused to approach again4 ,with such lamps the clockwork has been a source of trouble1 and it is liable to get out of order4 ,siemens' ,patent ,electric ,lamp4--,the lamp here described is actuated without clockwork2 it also automatically separates the carbons after they have approached too closely or touch1 and1 by this combined action of approaching and separating1 the carbon points are kept at a proper distance apart1 and a steady light is obtained4 ,the working parts are represented in the diagram ,fig4 #afi1 and at ,fig4 #agj is shown the size employed on board ship4 ,e is the horse-shoe magnet with the armature ,a placed in front of its poles a short distance from them4 ,a regulating screw b with the spiral spring f is attached to the lever ,a'1 forcing it against the stop d1 and withdrawing the armature from the poles of the electro-magnet4 ,when a current traverses the coils of the latter of sufficient strength to attract the armature and overcome the tension of the spring f1 contact is made at c1 which diverts the current from those coils4 ,the consequent release of the armature breaks contact at c1 the armature is again attracted1 and this action is repeated1 producing a vibrating motion of the lever and armature1 which continues as long as there is sufficient current to overcome the tension of the spring4 ,illustration3 ,fig4 #afi4 ,the spring pawl s at the upper end of the lever ,a'1 and oscillating with it1 actuates a ratchet-wheel u1 which is in gear with a train of wheels and the carbon holders2 it thus opposes their tendency to approach by pushing them apart1 tooth by tooth1 until the current is so much weakened by the increased length of electric arc that the armature and lever cease to oscillate enough to move the teeth of the ratchet-wheel1 and it rests near the stop d4 ,while in this position the spring pawl is released from the ratchet-wheel and the preponderating weight of the upper carbon holder causes the carbon points to approach again4 ,increase of current follows decrease of resistance1 the armature again oscillates1 and this cycle of action is continuously repeated4 ,when in action the movements of the carbons are scarcely perceptible1 but when1 by any external cause1 the carbons are separated so as to extinguish the light1 they immediately run together until they touch1 when they ignite and separate to a proper working distance by means of the electro-magnet above described4 ,the only operation requiring attention in the use of this lamp is the adjustment of the tension of the spring f4 ,when this tension is once regulated to the current at disposal1 the lamp will continue to give a steady light as long as the current remains uniform4 ,the relative rate of consumption of the two carbon points differs4 ,the positive carbon burns away rather more than twice as quickly as the negative carbon4 ,illustration3 ,fig4 #agj4 ,the duration of the light depends mainly on the lengths and sizes of the carbons4 ,provision is made in this lamp that the rack which supports the negative carbon may be made to gear either into the teeth of the same pinion as that of the positive carbon1 or into one of about half the size4 ,by these means the light1 when once focussed in a reflector1 will remain in focus as long as the carbons last1 whether permanent or reversed currents are employed4 ,besides its twofold application1 the lamp is very compact1 is simple in construction1 and therefore not likely to get out of order1 and it is capable of being regulated with great precision4 ,there is no spring to be wound up4 ,the contact need not be cleaned1 as the sparks are scarcely perceptible4 ,by removing two screws in the outside casing1 all the chief working parts can be easily removed and inspected4 ,carbons are made from the hard carbon deposited in the interior of gas retorts1 also from graphite4 ,various sizes1 both square and round in section1 of from #e to #bj mm4 in diameter1 are used in the electric lamp according to the intensity of the electric current4 ,those commonly employed are from #aj to #ab mm4 in diameter4 ,the carbons supplied with the ,siemens patent lamp are coated with a thin film of copper4 ,this enhances the cost somewhat1 but it greatly improves the result1 as the carbons burn longer1 and do not split1 when so coated4 ,by coating them the resistance is diminished1 except at the points1 so that all the heat is concentrated in the electric arc1 and a brighter light is the result4 ,when two dynamo machines are coupled together 7see page #bdh71 to give a very powerful current1 the sizes up to #bj mm4 are required4 ,the consumption varies a little1 but the average is from #c to #d inches per hour4 ,illustration3 ,fig4 #aga4 ,concentration of ,light4--,two kinds of concentrating apparatus are supplied in combination with the automatic lamp1 both of which are capable of giving a powerful parallel beam1 which will reach to an enormous distance1 and are well adapted for naval purposes4 ,the one kind consists of a parabolic reflector of stout metal1 its concave surface being silvered and burnished4 ,the apparatus is mounted with a ball-and-socket joint upon a wooden stand1 as shown in ,fig4 #aga4 ,the other kind is the ,fresnel catadioptric lens or holophote1 ,fig4 #agb1 which may be substituted for the reflector1 and gives a more powerful beam than one given by reflection4 ,the lens is surrounded by a metal case or lantern1 in which is placed the electric lamp upon a slide for focussing4 ,behind the carbon points a hemispherical reflector is placed1 to catch all the back rays1 and reflect them back through the lamp focus4 ,the entire lantern is capable of revolving on horizontal rollers1 and swings upon pivots4 ,two handles are placed at the back to manipulate it4 ,illustration3 ,fig4 #agb4 ,as the electric arc is much too bright to be looked into with the naked eye1 both concentrating apparatus are supplied with a lens1 called a focus or flame observer1 by means of which an image of the burning carbons is thrown upon small screens at the back1 so that the lamp can be easily adjusted without fatigue to the eye4 ,the focus observer is shown on the lamp in holophote1 ,fig4 #agb4 ,precautions4--,before starting the apparatus1 the electric lamp terminals and those of the dynamo machine must be connected up by means of the leading wires provided with each set of apparatus4 ,the terminals are marked ,c and ,z respectively1 and they should be connected1 ,c of machine to ,c of the lamp1 and ,z of the machine to ,z of the lamp1 in order that the electric current may be sent in the proper direction through the carbons of the lamp4 ,should it1 however1 be found that the top carbon 7which should consume twice as fast as that of the bottom one7 does not consume so fast as the bottom one1 it may be assumed that the dynamo machine has reversed its poles1 and the leading wires will consequently require changing across4 ,this reversal of poles1 though possible1 is of very rare occurrence4 ,illustration3 ,fig4 #agc4 ,the dynamo-electric machine should not be driven without its proper leading wires to lamp and lamp being connected up1 or at least an external resistance equivalent to that of the lamp 7which is approximately one ,siemens' unit7 must be inserted4 ,in other words1 the machine must not be driven when a wire of small resistance connects the two terminals ,c and ,z4 ,this is expressed more briefly by saying the machine must not be short-circuited4 ,if it is short-circuited when in motion the electric current becomes so powerful that it will leap from segment to segment of the commutator1 where very bright and large sparks will be seen1 and if continued would destroy the insulation1 thus weakening the current generated4 ,the leading wires should never be disconnected suddenly while the machine is revolving at its full speed1 as such a sudden interruption will produce an intense spark1 which will burn the ends of the wire where the contact is suddenly broken4 ,when it becomes necessary to disconnect the wires1 the belt should be pushed on to the loose pulley by means of the striking gear1 or the steam engine should be stopped4 ,it may be here stated that all connections should be cleaned bright and screwed tightly1 to ensure perfect metallic contacts being made4 ,coupling two ,machines4--,at ,fig4 #agd is shown a diagram of how to make the connections when coupling two machines in parallel circuit4 ,,mm'1 m1 m'1 represent the ends of the wires of the electro-magnets2 ,,bb' are the branches2 ,c and ,z are the terminals of each machine respectively4 ,illustration3 ,fig4 #agd4 ,the three ways in which the various wire connections of these machines are joined up1 and which are enough for all ordinary purposes1 are given below in paragraphs 7a71 7b71 and 7c74 7a7 ,when the machine is working singly and revolving in the direction indicated in ,fig4 #aff1 the following connections are made3-- ,m is connected with ,b1 ,m' ,b'1 m ,z1 m' ,c1 and the leading wires of the lamp are connected with ,c and with ,z as explained4 7b7 ,when working singly and revolving in the direction indicated in ,fig4 #afh3-- ,m is connected to ,b'1 ,m' ,b1 m ,z1 m' ,c4 ,thus the only change necessary when the machine is to be driven in the opposite direction to that for which it is made1 is to disconnect at ,b the wire from ,m to ,b and at ,b' the wire from ,m' to ,b'1 and to cross them4 ,the machine will then be connected as above 7b74 7c7 ,when working two machines in parallel circuit1 as in ,fig4 #agd1 they must be connected as follows 7that on the left of the page being called the first machine1 and that on the right the second machine73-- ,c of first to ,c of the second4 ,z ,z ,m ,b ,b ,m ,m' ,b' ,b' ,m' and then connect ,c and ,z of the second machine with the leading wires of the lamp4 ,the connections m to ,z and m' to ,c in each machine are the same as in cases 7a7 and 7b74 ,they do not require to be altered1 and may therefore be left out of consideration in all three cases 7a71 7b71 and 7c74 ,the whole of the connections here indicated can be quickly made by means of a cross-bar commutator or switch1 which is supplied with the machines in cases where such changes are likely to be required frequently4 ,this is usually attached to a wall1 leading wires being taken to it from the dynamo machines separately1 and others from the switch being led to the electric lamps4 ,the leading wires from machine to lamp should1 whenever possible1 be kept separate1 to prevent them rubbing together and making contact4 ,a distance of two inches is quite sufficient to prevent accidents of any kind4 ,when the leading wires are erected in places where they are likely to rub and chafe against hard substances1 it is advisable to enclose each wire separately in india-rubber tubing at all the points where they are likely to be rubbed4 ,this becomes very important on board ship1 where everything is in motion1 and special care is in consequence required4 ,some dynamo machines are coupled direct to the crank shaft of the steam engines2 they require the same kind of attention as others1 that is to say1 they should be driven at a uniform speed1 should be well oiled as well as the steam-engine1 and they should be kept clean and free from sharp grit4 ,application4--,the electric light used in the case of a direct attack by torpedo boats1 without the assistance of guard boats1 will not prove of much assistance1 on account of the very small space covered by the beam of light1 and therefore if the direction of attack is not exactly known1 the beam of light must be kept continually sweeping round the horizon on the chance of picking out the attacking boats1 and thus1 while flashing in one direction1 they may be approaching in another1 and effect their deadly mission4 ,every man-of-war should be fitted with at least three electric lights1 whereby the above-mentioned want of space covered would be to a considerable degree obviated4 ,if a powerful beam of light be thrown in a particular direction1 and there kept stationary1 all boats or vessels crossing its path at a distance not exceeding #afjj yards from the ship using the electric light1 would become distinctly visible to observers placed behind the light2 these vessels remaining visible as long as they continue in such a position that the beam of light acts as a background to them4 ,under very favourable circumstances1 the distance at which the above effect may be observed is much increased4 ,the parabolic reflector extends only about an arc of #cc at #edj yards' distance from the light4 ,one defect of this form of reflector is1 that it is rapidly dimmed by spray1 rain1 and by the particles given off by the carbons4 ,the catadioptric lens1 or holophote1 gives a far more powerful but a more concentrated beam than the parabolic reflector4 ,by means of such a beam of light1 a torpedo boat may be discerned at about one mile distance4 ,by adding divergent lens to the holophote1 a less powerful and less concentrated beam of light will be thrown out2 in this case about #bj of surrounding water would be well illuminated at about #ijj yards' distance1 while without the divergent lens there would be only about #e so illuminated but far more brilliantly4 ,the distance at which objects can be detected by the electric light depends on their size and colour1 more particularly on the latter4 ,the observer should as a rule be well removed from the light4 ,in the case of an electric light being thrown on the observer1 the vessel1 c41 using it would to that observer be invisible1 the light only being seen2 also when directed on any particular object1 surrounding objects would be thrown into shade4 ,the electric light will be found very useful for signal purposes by fitting a plane mirror in front of the catadioptric lens2 so arranged that it be turned to any desired angle to the axis of the beam of light4 ,by altering the angle of the mirror1 the reflected beam of light can be swept from the horizon on one side1 through the zenith1 to the horizon on the other side4 ,the time of passing the zenith being equivalent to the long and short flashes of the usual night signal code4 ,in addition to using the electric light to detect the approach of torpedo boats1 it may be used by the boats themselves to prevent the attacked vessel from discerning them4 ,in turret ships1 electric lights may be so arranged that the instant an object is brought into the field of the beam of light1 the turret guns will be bearing on it4 ,one great disadvantage of electric lights is the impossibility of protecting them from the enemy's fire1 and this is a defect that cannot be eradicated1 though it may be lessened1 by manipulating them from the tops of a ship4 ,torpedo ,guns4--,hitherto by torpedo guns has been meant small guns mounted on carriages so constructed that a shot may be fired into the water only a few feet from the ship's side1 or mitrailleuses1 ,gatlings1 c4 ,here the term is applied only to machine guns1 which are constructed to fire either volleys1 or1 extremely rapidly1 single shot1 each shot of which would be capable of penetrating and sinking torpedo boats1 such as ,messrs4 ,yarrow and ,thornycroft are daily launching from their yards4 ,of such weapons there are at present only two1 viz41 the ,nordenfelt and ,hotchkiss gun4 ,the former has1 after very exhaustive experiments1 been adopted by the ,english1 ,austrian1 ,swedish1 and other naval authorities1 while the latter has been adopted by the ,french government4 ,nordenfelt ,torpedo ,gun4--,this gun1 as it at present is constructed1 consists of four barrels of #a inch calibre4 ,the barrels are fixed in a horizontal plane1 and are not moved during the firing2 and the movement of the lever1 the loading1 the firing1 and the extracting are all performed in the same plane1 so that the elevation of the gun is not disturbed by the firing4 ,the gun is fed by means of hoppers1 each of which contains ten rounds per barrel1 i4 e41 forty shots4 ,the continuous supply of cartridges1 as well as the firing and extracting1 are all performed by one motion of the lever1 thus enabling the gunner to use his left hand to lay the gun4 ,a volley of four shots can be fired at the same moment1 or one shot can be fired separately4 ,eight shots can be fired in #a-a_/d seconds2 twenty1 thirty1 or forty shots can be fired at a rapidity of two hundred shots per minute without difficulty4 ,the recoil being taken up by the whole framework of the gun does not in the least disturb the aim4 ,the entire mechanism of the gun can be opened up without undoing a single screw1 in less than #bj seconds4 ,all the four spiral firing springs can be taken out1 without opening the rest of the mechanism1 in #a-a_/b seconds4 ,all the parts of the mechanism are made interchangeable1 so that reserved parts can at any time be substituted4 ,the gun can be placed on half cock1 so that the strikers do not act2 and for further security the lever can be locked4 ,the carrier block1 without which the gun cannot be fired1 is loose1 and can be taken away1 in case it becomes necessary to abandon a gun1 which is thus made useless to the enemy4 ,the bullets are solid steel1 weighing about #a_/b lb4 ,at #agfj yards at right angles this gun will penetrate a #c_/af inch steel plate1 which represents the thickness of the plates of a torpedo boat4 ,at #bjj yards at right angles it will penetrate one #c_/af inch steel plate placed in front of a #a_/b inch steel plate with a space of #c feet between them1 this target representing the plates and boiler of a torpedo boat4 ,at the same distance1 at #cj angle against the line of fire1 it will penetrate a #a_/b1 #a_/d1 or #c_/af steel plate4 ,the holes in some instances are from #f to #aa inches in length1 and #b-a_/b inches in height4 ,angle of depression #bj1 of elevation #cj1 and of direction #cfj4 ,weight of the gun #c-c_/d cwt41 and weight of carriage #b-a_/b cwt4 ,hotchkiss ,torpedo ,gun4--,this gun consists of a group of five barrels1 revolving on a central shaft1 a breech block1 containing the firing mechanism1 a feeding hopper1 and the necessary hand crank for training and firing4 ,the gun is mounted on trunnions attached to a vertical column1 which rests in a suitable socket bolted to the ship's side2 by this means a universal motion is obtained4 ,the essential difference between this and the ,nordenfelt gun is1 that the barrels and mechanism are put into rotatory motion4 ,another point of difference is that single shots only can be fired1 and not a volley1 as in the ,nordenfelt gun4 ,with the ,hotchkiss gun1 only some thirty shots can be fired in one minute at an advancing torpedo boat4 ,the weight of the ,hotchkiss steel shot is about #a lb41 but owing to the low velocity of the gun1 its penetrative power is little more than that of the ,nordenfelt #a_/b lb4 bullet4 ,the object to be gained in firing at an attacking torpedo boat is to sink her1 and not merely to kill or disable her crew1 for supposing the attack to be made with a contact spar torpedo1 and the boat to have reached within #cjj yards' distance from the ship1 then1 even if all the crew 7probably two or three men7 were disabled or killed1 the boat would1 if not sunk1 still carry out its work of destruction2 therefore the projectiles to be used under such circumstances should be only those capable of penetrating a torpedo boat's plates1 i4 e41 solid steel shot1 not shells4 ,diving4--,in laying down and in picking up submarine mines1 divers will be found extremely useful2 also in clearing a passage in a river1 c41 of an enemy's torpedoes in time of war4 ,during the late ,turco-,russian war1 the harbour of ,soukoum ,kaleh taken by the ,turks was popularly supposed to have been cleared of its mines by native divers 7,lazees71 but as the torpedoes so captured were never seen at ,stamboul1 it must have been a stretch of imagination2 probably such would have been done1 had there been any mines in the harbour to clear away4 ,the following is a general description of ,messrs4 ,siebe and ,gorman's improved diving apparatus4 ,the apparatus consists of #a4 ,an air-pump4 #b4 ,the diving dress4 #c4 ,the breast-plate4 #d4 ,the helmet4 #e4 ,the boots4 #f4 ,the crinoline4 ,air-pump4--,this improved air-pump consists of two double action cylinders1 each cylinder capable of supplying about #ace cubic inches per revolution4 ,the advantage of this air-pump is1 that it can supply air to two divers1 working independently and at different levels1 each diver being in direct connection with one of the cylinders4 ,the air-pipes are in lengths of #de feet and #cj feet1 made of vulcanised india-rubber with a galvanised iron wire imbedded2 this protects from corrosion1 and allows the air to pass through the pipes with less friction4 ,diving ,dress4--,the diving dress is made of solid sheet india-rubber1 covered on both sides with tanned twill2 it has a double collar1 the inner one to pull up round the neck1 and the outer one of vulcanised india-rubber to go over the breast-plate and form a water-tight joint4 ,the cuffs are also of vulcanised india-rubber1 and fit tightly round the wrist1 making1 when secured by the vulcanised india-rubber rings1 a water-tight joint1 at the same time leaving the diver's hand free4 ,breast-plate4--,the breast-plate is made of tinned copper1 and has a valve in front1 by which the diver can regulate the pressure of air inside his dress and helmet4 ,the outer edge of the breast-plate is of brass1 and is secured by screws to the outer collar of the dress4 ,helmet4--,the helmet is made of tinned copper1 and has a segment bayonet screw at the neck1 corresponding to that of the breast-plate1 which enables the helmet to be removed from the breast-plate by one-eighth of a turn4 ,it has three strong plate glasses in brass frames1 protected by guards2 two oval at sides1 and a round one on the front2 the front one can be unscrewed1 to enable the diver to give and take orders4 ,at the side is an outlet valve1 which1 by inserting a finger1 the diver can close1 and so rise to the surface4 ,the valve allows the foul air to escape1 and prevents the entrance of the water4 ,an elbow tube is securely fitted on the helmet1 to which is fixed an inlet valve1 to which the air-pipe is attached4 ,the inlet valve is made that the air can enter1 but in case of a break in the air-pipe it cannot escape4 ,the front and back weights are of lead1 heart-shaped1 and weigh about #dj lbs4 each4 ,boots4--,the boots are made of stout leather1 with leaden soles1 and are secured over the instep by a couple of buckles and straps4 ,each boot should weigh at least #bj lbs4 ,crinoline4--,the crinoline or shackle is used for deep water2 it is placed round the body and tied in the front of the stomach3 being supported by braces1 it affords protection to the stomach1 and enables the diver to breathe more freely4 ,ladder4--,an iron ladder should be provided with stays to bear against the side of the boat from which the diving is carried on1 to which may be attached 7if working in deep water7 an ordinary rope ladder1 with ash rounds1 and weighted at the end4 ,some divers have the ladder only #bj feet long1 to the last round a rope with a weight attached1 which rests on the ground2 by that means they descend4 ,directions for using the ,apparatus4--,the ladder having been fixed1 the position of the pump should be decided on1 and it should be securely lashed by means of the ropes attached to the handles down to a stage1 into which the screw-eyes should be fastened if necessary2 the pump should be placed out of the way of the divers1 the men attending on them1 and all the men employed4 ,the best position for the pump is facing the head of the ladder1 and about six feet from it4 ,while the diver is dressing1 the pump should be prepared for use1 the winch handles should be taken out of the pump case1 the nipples protecting the crank axles removed1 the nuts being replaced on their screws4 ,the nuts for the ends of the crank axles are taken off1 the fly-wheel placed on the shaft1 and the winch handles put on1 and secured by the nuts1 which are screwed home with the spanner4 ,the pump is always worked in its case4 ,the flaps covering the pressure gauges and that at the back of the pump case should be opened1 the screw on the overflowing nozzle of the cistern removed1 and the cistern filled with water2 the caps of the air delivery pipes should be removed1 the necessary lengths of air-pipe should be put together carefully with washers in place1 and all the screws must be worked home by means of the two double-ended spanners4 ,the air-pipes should be tested by holding the palm of the hand to the end of the pipe1 till the pressure shown on the pressure gauge is considerably above that corresponding to the depth the diver is to descend4 ,dressing the ,diver--,crinoline only for ,deep ,water4--,the diver having taken off his own clothes1 puts on a guernsey1 a pair of drawers1 very carefully adjusted outside the guernsey1 and securely fastened by the tape round the waist1 to prevent them from slipping down1 and then a pair of inside stockings4 ,if the water be cold1 the diver may put on two or more of each of the above articles4 ,he then puts on the crinoline and woollen cap1 drawing the latter well over his ears2 some divers find relief from putting cotton saturated with oil in their ears4 ,the shoulder pad is then put on1 and tied under the diver's arms4 ,he then gets into the diving-dress1 which in cold weather should be slightly warmed1 drawing it well up to his waist2 he next puts his arms into the sleeves1 an assistant opening the cuffs by means of the cuff expanders1 or by inserting the first and second fingers of both hands1 taking care to keep his fingers straight4 ,the diver1 by pushing1 forces his hand through the cuff4 ,he puts on a pair of outside stockings and a canvas overall to preserve the dress from injury4 ,the diver then sits down1 and the inner collar of the dress is drawn well up and tied round the neck with a piece of spun yarn1 and the breast-plate put on1 great care being taken that the india-rubber of the outer collar is not torn in putting it over the projecting screws of the breast-plate4 ,the four pieces of the breast-plate band1 which with the thumbscrews had been previously placed for safety in one of the boots1 are then put over the outer collar1 and secured to the projecting screws by means of the thumbscrews2 the centre screw of each plate should be tightened first4 ,it will generally be sufficient if the thumbscrews be screwed up hand-tight1 the spanner being only used when necessary4 ,the canvas overall is now adjusted and the boots are put on4 ,the rings are passed over the cuffs1 and the sleeves of the overall are drawn down to cover them4 ,if gloves are to be used1 the rings will be put on over them1 as well as the cuffs4 ,the helmet 7without the front bull's-eye7 is then put on2 before doing so1 the attendant should blow through the outlet valve of the helmet2 he can do so by placing his head in the interior1 and placing his mouth to the hole where the air escapes4 ,blow strongly2 if in proper working order1 the valve will vibrate4 ,a loop of the life line is placed round the diver's waist1 the line brought up in front of the man's body1 and secured with a piece of small rope passing round his neck1 or to the stud on the helmet4 ,the waist-belt is buckled on with the knife on the left side1 the end of the air-pipe being passed from the front1 through the ring on the belt on the man's left1 and up to the inlet valve on the helmet1 to which it is secured2 the upper part of the pipe is then made fast by a lashing to the stud on the left of the helmet4 ,the diver then steps on the ladder1 and two men are told off to man the pump4 ,the weights are then put on1 the front weight first1 the clips being placed over the studs on the breast-plate4 ,the back weights are then put on1 and the clip lashings over the hooks on the helmet1 and the two are secured to the diver's body by means of the lashing from the back weight1 which is passed round the waist1 through the thimble beneath the front weight1 and tied to the other end of the lashing at the back weight4 ,when the signalman is sure that all is right1 and that the diver understands all the signals1 he gives the word ,pump1 and screws the centre bull's-eye into the helmet securely2 this done1 he takes hold of the life line and pats the top of the helmet1 which is the signal for the diver to descend4 ,signals employed4--,the signalman is the responsible person1 and must be very vigilant all the time the diver is down2 occasionally he will give one pull on the life line1 and the diver should return the signal by one pull signifying all right2 if the signal be not returned1 the diver must be hauled up1 but if the diver wishes to work without being interrupted by signal1 he gives one pull on the line1 independently1 for ,all right2 let me alone4 ,if the signalman feels any irregular jerks1 such as might be occasioned by the diver falling into a hole1 he should signal to know if he is all right1 and if he does not receive any reply1 he should haul him up immediately4 ,if the diver from any cause is unable to ascend the ladder1 and wishes to be pulled up1 he gives four sharp pulls on the life line4 ,if while being hauled up the diver gives one pull1 it signifies ,all right2 don't haul me any more4 ,the diver should be hauled up slowly and steadily4 ,if the signalman wishes the diver to come to the surface1 he gives four sharp pulls on the line1 on which the diver should answer ,all right1 return to the foot of the ladder1 and signal to be hauled up4 ,one pull on the air-pipe signifies that the diver wants more air4 ,two pulls on the life line and two pulls on the air-pipe in rapid succession1 signify that the diver is foul and cannot release himself1 and requires the help of another diver2 on receiving such a signal1 no attempt should be made to haul the diver to the surface4 ,the above signals are to be invariably used2 but other signals may be arranged as is most convenient for any particular work1 as a great variety can be made with the life line and air-pipe4 ,the diver can communicate with the surface by means of a slate4 ,further information on this subject1 especially with regard to the foregoing diving apparatus1 will be found in ,messrs4 ,siebe and ,gorman's ,manual for ,divers4 ,,footnotes3 ,footnote ,v3 ,in wrought iron there is always some residual magnetism2 there is therefore no necessity to start the magnetism with a permanent magnet4 ,footnote ,w3 ,siemens' unit4 ,,chapter ,,xi4 ,,electricity4 ,,theory of ,electricity4--,the theory most readily understood1 and which most satisfactorily explains the various electrical phenomena1 is as follows3-- ,that every substance and every atom of the world is pervaded by a peculiar1 subtle1 imponderable fluid which is termed ,electricity1 but which is not known to exist1 or remains in a state of electrical equilibrium1 until evoked by certain causes4 ,the effect of causing a disturbance of this equilibrium is to increase the normal1 or natural1 electricity in some particles1 and to equally decrease it in other particles1 i4e4 what one loses the other gains4 ,an excess of natural electricity is denoted by the term positive1 or mathematical symbol 77 while a deficiency is denoted by the term negative1 or symbol 7-74 ,like electricities repel each other4 ,that is to say1 two bodies charged with an excess of1 or positive1 electricity1 being brought together repel each other1 neither wishing to increase the excess that has been evoked in them4 ,similarly in the case of two bodies charged with a deficiency of1 or negative1 electricity1 neither wish to add to the deficiency already there4 ,in both these cases there can be no tendency to electrical equilibrium1 which is the principle at work4 ,in the former case1 there being already too much1 more will but increase the disturbance4 ,in the latter case1 further deficiency will but add to the irregularity4 ,unlike electricities attract each other4 ,that is to say1 if two bodies1 one charged with positive1 or having an excess of electricity1 the other charged with negative1 or having a deficiency of electricity1 be brought together1 they will attract each other2 both being desirous of altering their existing state1 the one by decreasing its excess1 and the other by decreasing its deficiency of electricity4 ,in this case1 there will be a tendency to equilibrium1 caused by attraction4 ,the earth is supposed to be a vast reservoir of electricity1 from which a quantity can be drawn to fill up a deficiency1 and which is always ready to receive an excess from other bodies4 ,every body in nature has its own natural quantity of electricity1 and when an object is negatively electrified1 or has a deficiency in its normal quantity1 there is a tendency to receive a supply from any convenient source4 ,such an object would receive electricity from the earth if means were afforded2 and a body positively electrified1 would tend to part with its excess in the same manner4 ,where such facilities for establishing electrical equilibrium are afforded1 the result is the passage of a current of electricity4 ,conductors4--,sensible effects can be produced by electricity at great distances from the source1 provided there be a medium of communication1 that is1 good conductors to transfer it4 ,when a glass rod is rubbed with a piece of silk1 it becomes charged with an excess of1 or positive1 electricity1 and at the same time the silk becomes charged with negative electricity4 ,the glass rod will retain the positive electricity upon it for some time1 unless touched with the wet hand1 a wet cloth1 a metal1 c41 when it will instantly cease to be electrified4 ,the electricity is then said to have been conducted away1 and the bodies which allow it to run off the glass are called conductors of electricity4 ,metals1 water1 the human body1 charcoal1 damp wood1 and many other bodies are conductors4 ,those bodies which conduct electricity hardly at all1 such as the air1 silk1 glass1 sealing wax1 gutta percha1 india rubber1 c41 are termed nonconductors or insulators4 ,strictly speaking1 all substances conduct electricity in some degree1 and a nonconductor is merely a bad conductor4 ,in the following table the bodies are arranged in their order of conductivity1 i4e4 each substance conducts better than that which precedes it2 the first-named body is the best insulator1 and the last-named one is the best conductor4 ,dry air4 ,ebonite4 ,paraffin4 ,shellac4 ,india rubber4 ,gutta percha4 ,resin4 ,sulphur4 ,sealing wax4 ,glass4 ,silk4 ,wool4 ,dry paper4 ,porcelain4 ,dry wood4 ,stone4 ,pure water4 ,rarefied air4 ,sea water4 ,saline solutions4 ,acids4 ,charcoal1 or ,coke4 ,mercury4 ,lead4 ,tin4 ,iron4 ,platinum4 ,zinc4 ,gold4 ,copper4 ,silver4 ,though two substances are near one another in the above list1 they do not necessarily approach one another in their power of conducting4 ,for instance1 taking the conducting power of pure silver as represented by the number #ajj1 then ,pure ,copper will be equal to #iii1 ,gold will be equal to #ghj1 while ,zinc will be only equal to #bij1 and pure water1 which is half-way down the list1 will offer #f1ged millions more resistance than silver to the passage of the electric current4 ,the metals being the best known conductors1 are usually employed as the means of transferring the electric current from one place to another4 ,electric ,circuit4--,the conditions attending this operation are different from those of any other known method of transmission4 ,a complete circuit must always be formed by the electric current1 i4e4 it cannot start from one place ,a1 travel to another place ,b1 and cease there1 but the current must be completed before it can be said to have reached ,b4 ,there cannot be a current of electricity without a means of recombination1 which recombination must be at the source1 or place of original disturbance4 ,this place of disturbance or source must be considered as having two sides1 i4e4 at some spot the normal or natural electrical equilibrium is disturbed1 and electricity is separated into too much 7positive7 on one side1 and too little 7negative7 on the other side4 ,if then no means of recombination be afforded1 the electricities remain separated1 and no current exists2 but if a conductor be made to connect the two sides1 electricity is set in motion1 and a current established4 ,originally to form a circuit between two stations ,a and ,b1 a conducting wire and a return wire were necessary1 but in #ahcg ,steinway discovered that the earth itself answered all the purposes of a return wire1 in fact under favourable conditions much better4 ,thus1 to form a circuit between ,a and ,b1 a conducting wire is required1 and a buried metal plate at ,a and ,b1 the earth by these means taking the place of the return wire4 ,the aforesaid metal plates are technically termed earth plates4 ,the greater the size of the earth plates 7up to certain limits71 the deeper they are buried1 and the better the conducting power of the soil surrounding them1 the better conductors the plates become1 or the less resistance the earth portion of the circuit offers4 ,if either plate be not in communication with the earth1 or else be separated from the wire1 the circuit is not complete1 or1 as it is termed1 it is broken1 and no current will flow1 the signal not made1 torpedo not fired1 c4 ,short ,circuit4--,due to the fact that recombination1 or a tendency to equilibrium1 is always at work when electricity has been evoked1 the conducting path along which the electric current flows must be covered with a nonconducting substance1 or1 as it termed1 insulated1 or else the current would not perform its duty1 but escape to earth1 and so form what is termed a short circuit4 ,a current of electricity always chooses the easiest path to effect recombination1 or electrical equilibrium4 ,insulators1 c4--,on land1 telegraph wires are as a rule laid above the ground1 and therefore require supporting at every few yards2 this is done by means of posts1 and as these are formed of substances which are conductors of electricity1 the wires require to be insulated from them4 ,the insulators generally employed for such purposes are cup-shaped pieces of porcelain1 or pottery1 fixed to the head of the telegraph posts4 ,by means of these insulators1 the current of electricity is prevented from escaping to the earth by the post conductors4 ,a certain amount of leakage1 or loss of electricity1 must occur at each of these posts1 as there is no such thing as a perfect insulator4 ,when the wires are laid on the ground or under ground1 or under water1 they are insulated by covering them with gutta percha1 india rubber1 c41 and any loss of current is thus prevented4 ,methods of generating ,electricity4--,for the purposes of torpedo warfare there are two methods of evoking electricity1 viz4-- #a4--;,by chemical action4 #b4--;,by friction4 ,by ,chemical ,action4--,chemical action is the chief source of free electricity1 the representative of which is the galvanic1 or ,voltaic1 battery4 ,the electricity so generated is also termed dynamical electricity1 due to there being a constant electric current1 so long as the poles of the battery producing it are kept closed2 the electricity being thus in a dynamic or moving state4 ,by chemical action is signified that which occurs when two or more substances so act upon one another as to produce a third substance differing altogether from the original ones in its properties1 or when one substance is brought under such conditions that it forms two or more bodies differing from the original ones in their properties4 ,definition and ,properties of a ,voltaic ,cell4--,the ,voltaic cell consists of an insulating jar1 containing a liquid1 in which are placed two plates or pieces of dissimilar metals2 the liquid must be composed of two or more chemical elements1 one of which at least tends to combine with one or other of the metals1 or with both in different degrees4 ,by a ,voltaic battery is meant a number of cells above one2 this term1 however1 is often applied to a single cell when working by itself4 ,a simple ,voltaic cell1 element1 or couple1 consists of two metals placed in a conducting liquid4 ,if two metals--for instance1 zinc and copper--are placed in water slightly acidulated1 without touching each other1 no effect is apparent2 but if they be made to touch1 bubbles of hydrogen gas are formed over the copper plate1 and continue forming these until the plates are separated4 ,after being in contact for some time1 the copper plate will be found unaltered in weight1 but the zinc plate will have lost weight1 and the portion so lost will be found in the liquid in the form of sulphate of zinc4 ,the same effects are also produced by connecting the two plates by means of some conducting substance1 instead of placing them in contact4 ,zinc is invariably employed as one of the metal plates1 on account of the ease with which it dissolves in dilute acids2 and the greatest results are obtained when the second metal plate is not acted upon at all by the liquid1 for then the whole effect due to the oxidation of the zinc plate is obtained2 but when the second plate is also chemically acted upon1 then only the effect due to the difference between the two chemical actions is obtained1 for1 as will be explained further on1 they each act in directly opposite directions4 ,voltaic ,current4--,the ,voltaic current makes its appearance under the general laws of electrical action4 ,when a body charged with an excess of1 or positive1 electricity1 is connected with the earth1 electricity is transferred from the charged body to the earth2 and similarly when a body is charged with a deficiency of1 or negative1 electricity1 is connected with the earth1 electricity is transferred from the earth to the body4 ,generally whenever two conductors in different electrical conditions are put in contact1 electricity will flow from one to the other4 ,that which determines the direction of the transfer is the relative potential of the two conductors4 ,electricity always flows from a body at higher potential to one at lower potential1 when the two are in contact1 or connected by a conductor4 ,when no transfer of electricity takes place under these conditions1 the bodies are said to be at the same potential1 which may be either high or low4 ,the potential of the earth is assumed to be zero4 ,definition of ,potential4--,the potential of a body or point1 is the difference between the potential of the body or point1 and the potential of the earth4 ,difference of potential for electricity is analogous to difference of level for water4 ,now1 since1 when a metal is placed in a vessel containing a liquid1 electricity is produced1 the liquid becomes of a different potential to the metal1 each being electrified in an opposite way2 and therefore1 as above stated1 there being a difference of potentials1 electricity will tend to flow from one to the other4 ,this is evidence of a force being in action1 for there can be no motion without some force to produce it4 ,electro-motive ,force4--,electro-motive force is the name given to a peculiar force to which is due the property of producing a difference of potentials4 ,when it is said that zinc and water produce a definite electro-motive force1 what is meant is1 that by their contact a certain definite difference of potentials is produced4 ,the electro-motive force of a ,voltaic element may be termed its working power1 in the same way as the pressure of steam is the working power of a steam engine1 though this is not to be considered as the real source of power1 which1 as will be seen1 is uncertain4 ,due to the difference of potential of the metal and the liquid1 a current of electricity will flow from one to the other1 causing the chemical decomposition of the liquid1 and the reaction may be taken as the origin of the power employed4 ,but while the expenditure of energy 7which is necessary to produce a force7 is accounted for by taking the chemical action as the source of power1 the preceding cause of this chemical action1 viz4 the flowing of the current of electricity due to the difference of potential of the metal and the liquid1 must also have first involved the expenditure of energy2 thus the real source of power is very uncertain4 ,electrolytes4--,as before stated1 a ,voltaic cell consists of two plates of dissimilar metals1 which must be immersed in a liquid composed of two or more chemical elements1 one of which at least will combine with one or other of the metals1 or both in a different degree4 ,those liquids which are thus decomposed by the passage of a current of electricity are termed electrolytes4 ,the elements1 then1 forming the electrolyte may have chemical affinity for both metals1 though in a greater degree for one than the other4 ,oxygen is the most important element of an electrolyte1 and to the affinity for oxygen of the metals is the magnitude of the result and effect4 ,terms ,electro-positive and ,electro-negative4--,all metals have a definite relation to each other as to the potential which any one may have when brought into contact with another4 ,thus1 when zinc is brought into contact with copper1 the former has a potential positive to the latter1 i4e4 a current of electricity will tend to flow from the zinc to the copper4 ,the metals may be so placed in a list that each one would be positive to any of those that follow it2 it is then said to be electro-positive to them1 and they are electro-negative to it4 ,as those metals which are electro-positive to others have a greater affinity for oxygen1 and those that are electro-negative to others a less affinity for this element1 the terms electro-positive and electro-negative signify1 in effect1 greater or less affinity for this element4 ,conversely1 oxygen will combine more readily with the former than with the latter4 ,the following list shows the commoner metals arranged in electro-chemical order4 ,zinc4 ,lead4 ,tin4 ,iron4 ,antimony4 ,copper4 ,silver4 --,gold4 ,take the case of a ,voltaic cell composed of zinc and copper plates immersed in water4 ,the passage of electricity through the water will decompose it into its elements hydrogen and oxygen1 the latter having an affinity for both the plates1 but considerably more so for the zinc plate4 ,then1 an electro-motive force will be generated at each metal1 and these forces will act in opposition to each other1 but the greater strength of the one will overcome the weaker1 and the real power of the electric current will be the difference between the two4 ,definition of ,elements4--,the battery plates are termed the positive and negative elements4 ,a ,voltaic battery has two poles--a positive and a negative--which are the terminations of the plates4 ,direction of ,current4--,the course of the current in a ,voltaic cell is as follows3--,within it leaves the electro-positive plate 7or element71 and flows to the electro-negative plate1 but outside the cell 7or as it were on its return path7 it flows from the positive pole to the negative pole4 ,the current always leaves the battery by the positive pole1 and thus the copper is the negative element1 but the positive pole1 because the current leaves the battery by it2 and the zinc is the positive element because the current begins there1 within the cell1 and the negative pole because it ends there1 outside4 ,the positive pole is the terminal of the negative plate1 and vice vers4 ,there is but one current from a battery1 viz4 a positive one2 what is called a negative current is merely the positive current passing in the reverse direction from the same pole1 that is1 the positive pole4 ,single and ,double ,fluid ,batteries4--,galvanic batteries may be divided into single fluid and double fluid batteries4 ,the simplest form of galvanic cell practically in use is a single fluid cell1 consisting of a zinc and a copper element1 immersed in water slightly acidulated by the addition of a little sulphuric acid4 ,in a battery of several cells1 the zinc and copper plates are generally soldered together in pairs1 and placed in a long stoneware or glass trough1 divided into separate cells by means of partitions4 ,by filling the cells with sand1 this battery is made more portable1 the plates being thus supported1 and the liquid prevented from splashing about during transit4 ,in this form it is called the common sand battery4 ,action in a ,single ,fluid ,cell4--,the following process goes on in the single fluid cell when the circuit is closed--that is1 when the battery is set to work4 ,the water 7composed of hydrogen and oxygen7 is decomposed by the passage of the electric current1 and oxide of zinc is formed4 ,the oxygen of the water having greater affinity for the zinc1 leaves the hydrogen4 ,the zinc during the process is being consumed1 as coal is consumed when it burns1 while combining with the oxygen of the air4 ,this oxide of zinc combines with the sulphuric acid1 and forms sulphate of zinc2 this salt is found to accumulate in solution in the liquid of the cell4 ,at the same time the hydrogen of the water goes to the negative or copper plate1 and gathers over it in bubbles4 ,the process will be better seen by the accompanying plan of the chemical decomposition and recombinations4 ,sulphuric ,acid ,zinc ,sulphate of zinc found at ,oxygen ,oxide of ,zinc positive plate4 ,water ,hydrogen ,hydrogen found at negative plate4 ,no single fluid cell can give a constant electro-motive force because of the polarisation of the plates4 ,definition of the term ,polarisation4--,the word polarisation means that the plates become coated with the products of the decomposition of the electrolyte1 producing a diminution of current4 ,in the above described battery1 the hydrogen gathers on the surface of the copper plate1 and an electro-motive force is set up which counteracts the electro-motive force producing the current--the copper plate is said to be polarised4 ,by the bubbles of hydrogen collecting on the face of the negative plate1 the surface in contact with the liquid is gradually decreased2 thus the plate becomes practically smaller1 and a single fluid cell which at starting gave a good current soon shows that it is really weakened4 ,the consequence is that the zinc is consumed extravagantly as well as the acid1 and the cell working with poor results4 ,also the resistance of the cell is increased1 due to the sulphuric acid1 which is added to the water to increase its conductivity1 being gradually used up1 by combining with the oxide 7see plan7 and forming sulphate of zinc4 ,liquids are very bad conductors of electricity2 the greater part of the ordinary internal resistance of a battery arises from this cause4 ,the common sand battery is the worst of all batteries as regards constancy of electro-motive force1 the polarisation being greater in this battery than any other because the gas cannot readily escape4 ,the common copper and zinc cell is the next in order of demerit4 ,the ,smee single fluid cell1 in which the negative plate is a platinum instead of a copper one1 is better than the copper zinc cell1 because the free hydrogen does not stick to the rough surface of the platinum plate so much as to the copper4 ,double ,fluid ,batteries4--,all the defects of the single fluid battery1 which are as follows-- #a4 ,diminution of electro-motive force1 #b4 ,inconstancy1 #c4 ,increase of internal resistance1 are remedied in the double fluid battery1 of which the ,daniell's cell was the first invented1 and is a good example4 ,of this kind of cell many forms are in use1 but the principle is the same throughout4 ,there is a positive and negative element1 and the cell is divided into two receptacles for the two fluids4 ,in the most constant form of ,daniell cell1 the zinc is plunged into a semi-saturated solution of sulphate of zinc1 the copper in a saturated solution of sulphate of copper1 and these two solutions are separated either by a porous barrier1 or by taking advantage of the different specific gravities of the two solutions4 ,by a saturated solution is meant a liquid which has dissolved as much of the substance as it possibly can4 ,the ,chemical ,action of a ,daniell ,cell4--,the chemical action of this form of ,daniell cell is as follows3-- ,the zinc electrode combines with oxygen2 the oxide thus formed combines with sulphuric acid and forms sulphate of zinc4 ,oxide of copper is separate from the sulphate2 and the copper in this oxide is separated from the oxygen4 ,the oxygen of the water is separated at the zinc electrode from the hydrogen1 and at the other electrode this hydrogen recombines with the oxygen from the oxide of copper4 ,this alternate decomposition and recombination of the elements of water can neither increase nor decrease the ,e4,m4,f4 of the cell1 the actions being equal and opposite4 ,the result of the series of actions above described is that the sulphuric acid and oxygen of the sulphate of zinc are transmitted to the zinc1 combine with it1 and form fresh sulphate of zinc2 the sulphuric acid and oxygen of the sulphate of copper are transmitted to the zinc set free by the above process1 and reconvert it into sulphate of zinc2 the copper of the sulphate of copper is transmitted to the copper electrode1 and remains adhering to it4 ,the whole result is therefore the substitution of a certain quantity of sulphate of zinc for an equivalent quantity of sulphate of copper1 together with a deposition of copper on the copper or negative electrode4,x ,the following is a plan of the process3-- ,zinc444444444444 4 ,sulphate of ,zinc found ,oxide of ,zinc44 4 at positive plate4 ,water ,oxygen44 4 ,hydrogen44444444444444444444444 ,sulphuric ,acid44444 ,water4 ,sulphate of ,oxygen44 ,copper ,oxide of ,copper ,copper at negative ,copper4444 plate4 ,description of the ,callaud and ,mari-,davy ,batteries4--,the ,voltaic batteries in general use for the different purposes of torpedo warfare have been fully described in ,chapter ,,iv41 and therefore it will be only necessary here to explain the construction of the ,callaud and ,mari-,davy batteries1 these being much used abroad in connection with telegraphy4 ,the ,callaud cell1 named from the inventor1 is a modification of the ,daniell cell1 and is also called a gravity battery1 the liquids being simply prevented from mixing by the law of gravity forbidding the heavier of the two from rising through the lighter4 ,it consists of a thin plate of copper1 which is laid on the bottom of a good insulating jar having an insulated wire leading up the side1 and on this plate are placed crystals of sulphate of copper4 ,a solution of sulphate of zinc is then poured in1 and on the top is fitted a zinc plate1 which forms the positive element4 ,the vessel must not be shaken1 or the sulphate of copper when dissolving will mix with the solution above it4 ,the ,mari-,davy cell consists of a carbon electrode in a paste of proto-sulphate of mercury and water contained in a porous pot1 and a zinc electrode in dilute sulphuric acid1 or in sulphate of zinc4 ,the ,circuit4--,in connection with the manipulation of batteries1 there is one important item to consider1 viz4 the resistance in the circuit1 which may be divided into external and internal4 ,resistances4--,the external resistance in practice is that which exists in the conducting line1 and the various instruments connected with it4 ,the internal resistance is that which exists in the battery itself4 ,all known conductors oppose a sensible resistance to the passage of an electric current1 and the strength of the current1 or in other words1 the quantity of electricity passing per second from one point to another1 when a constant difference of potentials is maintained between them1 depends on the resistance of the wire on the conductor joining them4 ,a bad conductor does not let the electricity pass so rapidly as a good conductor1 that is1 it offers more resistance4 ,resistance in a wire of constant section and material is directly proportional to the length1 and inversely proportional to the area of the cross section4 ,the electrical resistance of a conductor must not be considered as analogous to mechanical resistance1 such as the friction which water experiences in passing through a pipe1 for this frictional resistance is not constant when different quantities of water are being forced through the pipe1 whereas electrical resistance is constant whatever quantity of electricity be forced through the conductor4 ,application of ,ohm's ,law4--,ohm's law1 which governs the strength of the current1 is expressed by the equation ,c ,e _/ ,r or ,r ,e _/ ,c or ,e ,,cr4 ,where ,c is the strength of the current2 ,e is the ,e4,m4,f4 or difference of potentials2 and ,r is the resistance of the circuit4 99_/ ,in words1 ,ohm's law means that the strength of the current is directly proportional to the ,e4,m4,f41 and inversely proportional to the resistance of the circuit4 ,as before stated1 the resistance of the circuit consists of an external and an internal resistance1 therefore when these resistances are separately considered1 the equation ,c ,e _/ ,r must be converted into ,c ,e _/ 7x r71 where x is the external1 and r the internal1 resistance4 ,the resistance of the battery or the internal resistance depends on the size of the plates and the distance between them1 that is1 it is directly proportional to the distance1 and inversely proportional to the size4 ,the electro-motive force of a battery is dependent generally on the number of cells joined in series1 and not on the size of the plates4 ,the cells of a battery may be joined in two ways1 as follows3-- #a4 ,in series3 that is1 by connecting the negative element of one cell to the positive element of another1 and so on4 #b4 ,in multiple arc3 that is1 by connecting negative to negative1 and positive to positive2 which is the same as increasing the size of the cells4 ,if the conductor between the battery poles be such that the external resistance x may be practically left out1 then ,c ,e _/ r1 and no change in the strength of the current will be effected by adding any number of cells in series1 as r will increase equally with ,e1 and therefore ,c will remain the same2 but if under the same conditions the cells be joined in multiple arc1 then r will decrease as ,e increases1 and therefore ,c will be increased4 ,thus with a short circuit of small external resistance1 the strength of the current will be increased by increasing the size of the plates1 or by joining the cells in multiple arc1 but not in series4 ,if the conductor between the poles of the battery be such that the external resistance x becomes very great1 then ,c ,e _/ 7x r71 where x is very great compared to r4 ,by joining the cells in multiple arc r is decreased1 but ,e and x remain the same1 and therefore ,c is not materially altered1 as x is very great compared to r4 ,by connecting the cell in series1 r is increased1 and so is ,e1 but as r is still very small compared to x1 the strength of the current ,c is increased4 ,thus with a long circuit of great external resistance1 the strength of the current will be increased by joining the cells in series1 but not in multiple arc4 ,when the external resistance x is neither very large nor very small in comparison with the battery or internal resistance r1 then the strength of the current ,c will be increased by adding the cells in series1 and also in multiple arc4 ,by the former process the ,e4,m4,f4 ,e is increased more than the resistance of the circuit ,r or 7x r71 and by the latter process1 the ,e4,m4,f4 ,e is unaltered1 whilst the circuit resistance 7x r7 is decreased4 ,all the above may be practically demonstrated by the employment of suitable galvanometers4 ,frictional ,electricity4--,frictional electricity is produced by the friction of two insulators4 ,there is no difference whatever in kind between ,voltaic and frictional electricity4 ,comparison with ,voltaic ,electricity4--,the electricity generated by friction possesses a great electro-motive force1 producing on even a small conductor a large charge1 whereas the electricity generated by the galvanic cell possesses a very small electro-motive force1 and produces only a small charge on a small conductor4 ,but when the conductor is large1 the electricity produced by the galvanic cell will almost instantaneously charge the conductor to the maximum potential it can produce1 the galvanic cell developing an immense quantity of electricity by the chemical reaction2 whereas the quantity developed by friction between two insulators is so small1 that if it be diffused over a large conductor the potential of the conductor will be very little increased4 ,the late ,professor ,faraday has proved that one cell of a ,voltaic pile possesses the same quantity of electricity as an ordinary sized frictional machine after being wound round #hjj1jjj times1 thus showing the contrast between the qualities of frictional and ,voltaic electricity4 ,the electricity of the frictional machine and that of the galvanic battery may be made to produce the same effect1 there being no difference in kind between them4 ,frictional electricity can be made to pass in a current1 but it is comparatively feeble4 ,again1 ,voltaic electricity can be made to produce a spark1 but under ordinary circumstances it scarcely amounts to anything4 ,description of a ,frictional ,electric ,machine4--,a frictional electrical machine consists of a vulcanite or glass disc or cylinder1 which is made to revolve between cushions or rubbers of leather or silk4 ,by the friction the 7silk7 rubbers become negatively1 and the glass disc or cylinder positively1 electrified4 ,the revolving disc immediately after contact with the fixed rubbers passes close by a series of brass points1 which are connected with a condenser4 ,these points collect the positive electricity of the glass1 the rubbers being put to earth4 ,the positive electricity which the glass loses is supplied through the rubber2 a stream of negative electricity flows from the rubbers to the earth during the charging of the conductor or condenser2 in other words1 the positive electricity flows from the earth to the rubber1 whence it crosses to the glass disc and so to the condenser4 ,definition of a ,condenser4--,a condenser is an arrangement for accumulating a large quantity of electricity on a comparatively small surface4 ,the ,leyden ,jar4--,the ,leyden jar1 which is the original type of the condenser1 or accumulator1 consists of a glass jar coated inside and out1 up to within a few inches of the mouth1 with tinfoil pasted on1 but having no connection with each other4 ,the mouth is usually closed by means of a wooden stopper1 through which a brass rod passes1 to the head of which is affixed a brass knob1 c41 the rod and knob being metallically connected with the inner coating by means of a chain4 ,the ,leyden jar may be charged either by connecting the outer coating to earth 7the rubbers of the machine being also to earth71 and the inner coating to the conductor of the machine2 or else by connecting the outer coating to the rubbers1 and the inner coating to the conductor1 a complete circuit being necessary to charge the jar as highly as the frictional electrical machine will admit of4 ,the conductor of the machine being charged1 also forms a kind of ,leyden jar1 the conductor in this case being the inner coating1 the air1 the dielectric1 and the nearest surrounding conductors1 such as the walls of the room1 c41 being the outer coating4 ,meaning of ,dielectric4--,by dielectric is meant a non-conducting medium1 which in the case of the ,leyden jar is the glass4 ,frictional ,electricity very little used for ,torpedo ,purposes4--,frictional electricity is now seldom used in connection with torpedo warfare1 as on account of its very great power1 or electro-motive force1 a very perfectly insulated cable must be employed1 which is somewhat difficult to obtain2 it is also necessary to employ a condenser1 which requires a certain time to charge4 ,for these and other reasons1 frictional electricity has been abandoned for the far more practical ,voltaic electricity4 ,magnetism4--,a magnet is a piece of steel1 which has the peculiar property1 among others1 of attracting iron to its ends4 ,certain kinds of iron ore1 termed the loadstone1 have the same properties4 ,the word magnet is taken from the country ,magnesia1 where the loadstone was first discovered4 ,magnetism in a body is considered to be a peculiar condition caused by electrical action4 ,both electricity and magnetism have the power of communicating their properties to other bodies without being in contact with them1 i4e4 inducing the power1 which on the bodies being placed far apart becomes insensible4 ,the ,poles of a ,magnet4--,every magnet has two poles1 called the north and south poles4 ,a magnetic steel needle if pivoted on an upright point1 or suspended from its centre1 will fix itself1 pointing north and south2 in ,england the end of the needle pointing to the north is termed the north pole1 but in ,france it is termed the south pole4 ,the reason of this difference is owing to the fact that the north pole of one magnet attracts the south pole of another1 and therefore1 as the earth is considered as one vast magnet1 the end of the magnetic needle attracted to the north pole of earth magnet should be the south pole of the magnet2 thus the ,french south pole in a magnet is the ,english north pole1 and vice vers4 ,permanent ,magnets4--,a piece of steel when magnetised is termed a permanent magnet1 because it retains its magnetism for a considerable length of time2 but soft iron cannot be permanently magnetised4 ,a piece of soft iron rendered magnetic by induction retains a portion of its magnetism for some time after it has been removed from the magnetic field1 by reason of what is called its coercive force4 ,this remnant of magnetisation is called residual magnetism4 ,effect of an ,electrical ,current on a ,magnetic ,needle4--,a magnetic bar or needle pivoted on its centre will point north and south1 but if an electric current is caused to flow along a wire parallel to and either over or under the magnetic needle1 the latter will be turned from its position1 and remain so as long as the current continues2 on the current ceasing the needle will resume its original position4 ,the magnetic needle can be turned either to the east or the west1 according to the direction and course of the electrical current4 ,thus3-- ,current from ,s4 to ,n4 over deflects to ,w4 ,current from ,n4 to ,s4 under deflects to ,w4 ,current from ,n4 to ,s4 over deflects to ,e4 ,current from ,s4 to ,n4 under deflects to ,e4 ,the ,galvanometer1 the ,mirror1 and ,thomson's reflector all depend on this principle for their usefulness4 ,these instruments have been fully described in ,chapter ,,iv4 ,the ,electro-,magnet4--,if a piece of insulated wire be coiled round a rod of soft iron1 and a current of electricity be made to pass through the coil1 the iron core becomes magnetic as long as the current passes2 when the current ceases the magnetism disappears4 ,during the passage of the electric current1 the iron core possesses all the properties of a magnet4 ,therefore if a piece of iron were placed near its poles it would be attracted and released from attraction as often as the current passed or ceased2 and supposing such a piece of iron to be retained by a spring1 c41 a series of movements1 attraction1 and drawing back would be effected4 ,a piece of iron so arranged is termed an armature1 and the instrument is called an electro-magnet4 ,the coil of wire must be carefully insulated1 or else the electric current will pass through the iron core to earth instead of performing its proper work4 ,an electro-magnet is much more powerful than a steel magnet of equal dimensions1 and depends on the strength of the current by which the magnetism is induced1 and the number of turns of wire round the core4 ,the north and south poles of an electro-magnet are determined by the direction in which the current flows through the wire4 ,at the south pole the current passes with the hands of a watch1 and at the north pole against the hands of a watch4 ,definition of the ,ohm4--,the ohm is the standard used for electrical resistance2 it is obtained by observing what effect is produced by a current of electricity on a certain conductor in a certain time4 ,the ohm is a small coil of ,german silver wire representing the resistance overcome by a current in a certain time4 ,,footnotes3 ,footnote ,x3 ,jenkins' ',electricity4' ,,appendix4 ,mc,evoy's ,single ,main ,system4--,hitherto in connection with a system of electrical submarine mines1 it has been necessary to employ either a single cable between each submarine mine and the torpedo station1 or a single cable1 termed a multiple cable1 containing a limited number of insulated wires1 leading from the station1 and branching off from a junction box to each mine1 by which considerable cost and complication is incurred4 ,to remedy the above serious defects of such a system1 and also to simplify the arrangement of electrical tests1 ,captain ,mc,evoy has devised and patented the following apparatus2 at the firing1 or torpedo station1 the end of the single main cable1 that is1 the single core cable leading to the junction box1 is connected to a make and break contact apparatus1 by which1 by the movement of a dial or pointer around a fixed centre1 a battery can be successively put in connection with the wire1 and disconnected from it1 in a somewhat similar manner to ,wheatstone's step by step dial telegraphs4 ,in the junction box at the opposite end of the single core main cable is an electro-magnetic apparatus for working a dial or pointer in exact unison with the aforesaid dial or pointer at the torpedo station4 ,this junction box dial or pointer serves as a contact maker to put the wire of the main cable successively in contact with the branch wires leading to the several torpedoes1 as it is caused to turn with a step by step motion by the sending of a succession of currents from the firing station4 ,as the contact maker completes the circuit between the main cable and one of the branch wires1 the current passes from the cable through the wire1 and through the fuze of that particular torpedo to earth2 but when any one or other of the torpedoes is to be exploded1 the circuit between the main cable and the torpedo wire being completed1 it is only necessary to send a current through the main cable of sufficient strength to ignite the fuze1 and so explode the mine4 ,the strength of the current used for giving the aforesaid step by step motion to the junction box dial or pointer is not sufficient to cause the ignition of the fuzes in the torpedoes4 ,again1 if it be desired that the torpedoes should be so arranged that when any of them are struck by a passing vessel1 the fact of its having been struck should be instantly signalled to the firing station4 ,the dial apparatus in the junction box is arranged so that at one point of its revolution1 termed the zero point1 all the torpedo branch wires are in circuit with the main cable1 and that then a constant current is passing from the firing station through all the circuit closers1 and out through resistance coils to earth4 ,in this case1 if one of the circuit closers be struck1 and therefore short circuit formed1 the current passes direct to earth without going through the aforesaid resistance1 and the fact of its having done so is at once indicated by a galvanometer at the firing point1 by the movement of which a bell is rung at the station4 ,the operator can then explode such torpedo at once by merely switching in the firing battery4 ,at the same time the passage of the strong firing current may fuze a connection in the junction apparatus1 by which the exploded torpedo is detached1 i4e4 the direct earth connection of such a torpedo is cut off1 and the remaining submarine mines are left in proper working order2 this effect may also be arrived at by other means4 ,general ,description of ,apparatus4--,the following is a general description of this exceedingly clever and useful invention3-- ,at ,fig4 #afh is shown a diagram view of the apparatus4 ,a is the instrument at the firing point on the shore or vessel2 ,b is the cable wire led to a submerged box situated near the spot where the several torpedoes are grouped2 ,c is the instrument enclosed in the submerged box2 ,d1 ,d are insulated wires led away from the box to the several torpedoes1 there being a separate wire for each torpedo4 ,each of the wires ,d is coupled to one or other of a series of metallic contact pieces ,e ranged in a circle round the axis of a metallic pointer ,f1 which can be turned with a step by step motion and successively brought into electrical contact with the several contact pieces ,e4 ,the axis of the pointer is in electrical communication with the wire of the cable4 ,the wire from the cable is first led to the coils of an electro magnet ,g1 and thence passes to the axis of the pointer4 ,h is a magnetic armature in front of the electro magnet ,g2 when a positive current of sufficient strength is sent through the cable the armature is rocked in one direction1 and when a negative current is sent1 it is rocked in the opposite direction4 ,from the armature motion is transmitted to a pawl which works into the teeth of a ratchet wheel on the axis of the pointer ,f1 so that by sending a succession of reversed currents of sufficient strength through the cable1 the pointer ,f is turned with a step by step motion and is successively brought into electrical contact with the several contact pieces ,e4 ,illustration3 ,mc4,,evoy',s ,,single ,,main ,,system ,,plate ,,liv4 ,in the instrument1 at the firing point a is a handle1 by the turning of which a step by step motion is given to the pointer of a dial b and a simultaneous movement to the pointer ,f of the instrument ,c in the submerged box4 ,when the handle a has made a half turn it couples one pole of the battery to the cable and the other to the earth connection1 and when it has made a complete turn the connections are reversed4 ,the pointer of the dial b then moves forward from one division of the dial to the next1 and simultaneously the pointer ,f is turned in unison with it4 ,the operator at the firing point can therefore always see which of the torpedoes is in electrical connection with the wire of the cable1 and he can test each torpedo in succession by moving a handle1 say at h1 to cause the current passing back from the torpedo to pass through a galvanometer at e1 and by the movement of the needle of the galvanometer it can be seen whether the resistance of the circuit through this torpedo is in its normal and proper working state4 ,when the pointer of the dial b is brought to zero1 or as it is marked in the drawing to signal1 then the pointer ,f of the apparatus ,c is in electrical communication with a contact point which is coupled to all of the branch wires ,d1 and usually the apparatus is left in this condition1 the handle a being then locked and prevented from turning by a bolt actuated by a handle at ,g4 ,the current from the battery at the firing point then passes to earth through the resistances in all of the torpedoes4 ,if now any one or other of the torpedoes is struck by a passing vessel and the wire from its fuze put directly to earth1 so that the current passes freely to earth instead of having first to pass through the resistance1 the fact of the current passing freely to earth is notified at the firing point by the movement of the needle of a galvanometer d2 the movement of the needle of this galvanometer effects an electrical connection by which a small battery is caused to sound a bell at c4 ,the operator at the firing point can then if he pleases at once fire the torpedo that has been struck by moving a handle at f and coupling up to the wire of the cable a battery of greater strength2 the strong firing current will pass to earth through the fuze of the torpedo that has been struck1 and will ignite this fuze1 but will not affect the fuzes of the other torpedoes1 as to pass through these fuzes it has also to pass through resistances which impede its passage and reduce its strength1 so that the portion of the current which passes to earth through them is not of sufficient strength to ignite the fuzes4 ,when the fuze of any one or other of the torpedoes is exploded by the passing of a strong firing current through it1 the wire leading from the box ,c to this torpedo is simultaneously cut off from electrical connection with the contact pin ,e to which it was previously connected1 and this pin is put to earth through a resistance either somewhat greater or less than the resistances in the torpedoes1 so that the firing of one or more of the torpedoes does not interfere with the power of being able to turn the pointer ,f of the apparatus ,c in unison with the pointer of the dial b4 ,afterwards the operator at the firing point can ascertain which of the torpedoes has been fired by passing the pointer of the dial b to each of the divisions of the dial in succession1 and ascertaining by the galvanometer a the resistance of the circuit through each of the torpedoes1 so that he at once ascertains which torpedo has been put to earth through the greater or less resistance4 ,the cutting off of the wire ,d from its contact ,e when a strong current is passed through it may be effected by the wire being coiled around an iron core forming an electro magnet1 which when a strong current is passed through the wire is of sufficient strength to shift the position of a contact apparatus and then effect the required alterations in the connections1 but which is not of sufficient strength to effect any change when the weaker currents used for the signalling and testing operations are passed through the wire4 ,it will be evident that with the above described apparatus any one or other of the torpedoes can if desired be exploded by the operator at the firing point whenever he desires to do so4 ,to effect this he would by turning the handle a bring the pointer of the dial b opposite to the division of this dial2 that would indicate that the cable had been brought into electrical communication with the torpedo required to be exploded1 and then when it is ascertained by previously adjusted sight points that the vessel is above the torpedo1 he can fire the torpedo by passing a strong firing current to the cable4 ,in this way the apparatus can be used for firing any one or other of a group of sunken torpedoes1 or if the torpedoes are buoyant ones1 they need not be fitted with apparatus for putting the wire from their fuze directly to earth whenever the torpedo is struck by a passing vessel4 ,the same arrangement of apparatus can also be used for firing any one or other of a number of mines or torpedoes on land and for separately testing the firing mechanism of each mine whenever desired4 ,captain ,mc,evoy's single main system will shortly undergo a series of experiments under the supervision of the ,english torpedo authorities at ,chatham1 which will most probably result in its adoption by the ,english government1 and also by the principal continental powers4 ,,table,y ,,showing ,,the ,,value ,,of ,,the ,,fractions ,a ,,and ,b ,,for ,,every ,,half ,,degree4 --------------------------------- ,a ,b ,arc4 #aej alpha#aej - alpha -------------------------- alpha#aej - alpha#aej alpha --------------------------------- #ade #eijj #jjag #adde #eced #jjai #add #dijj #jjbj #adce #deae #jjbb #adc #dahf #jjbd #adbe #cijj #jjbf #adb #cfej #jjbh #adae #cdbi #jjbi #ada #cbcc #jjca #adje #cjeh #jjcc #adj #bijj #jjce #acie #bgeg #jjcf #aci #bfbg #jjch #ache #beji #jjdj #ach #bdjj #jjdb #acge #bcjj #jjdd #acg #bbjh #jjde #acfe #babb #jjdg #acf #bjdc #jjdi #acee #aifi #jjea #ace #aijj #jjeb #acde #ahce #jjed #acd #agge #jjef #acce #agah #jjeh #acc #affe #jjfj #acbe #afad #jjfb #acb #aefg #jjfd #acae #aebb #jjff #aca #adgi #jjfh #acje #adch #jjgj #acj #adjj #jjga #abie #acfc #jjgc #abi #acbh #jjge #abhe #abie #jjgg #abh #abfd #jjgi #abge #abcc #jjha #abg #abjd #jjhc #abfe #aagf #jjhe #abf #aaej #jjhg #abee #aabd #jjhi #abe #aajj #jjia #abde #ajgf #jjic #abd #ajed #jjie #abce #ajcb #jjig #abc #ajaa #jjii #abbe #iia #jaja #abb #igb #jajc #abae #iec #jaje #aba #ice #jajg #abje #iag #jaji #abj #ijj #jaaa #aaie #hhd #jaac #aai #hfh #jaae #aahe #heb #jaag #aah #hcg #jaai #aage #hbc #jaba #aag #hji #jabc #aafe #gif #jabf #aaf #ghb #jabh #aaee #gfi #jacj #aae #geg #jacb #aade #gde #jacd #aad #gcc #jacf #aace #gbb #jaci #aac #gaa #jada #aabe #gjj #jadc #aab #fhi #jade #aaae #fgi #jadg #aaa #ffi #jaej #aaje #fei #jaeb #aaj #fej #jaed #ajie #fda #jaef #aji #fcb #jaeh #ajhe #fbc #jafj #ajh #fad #jafc #ajge #fjf #jafe #ajg #eig #jafh #ajfe #ehi #jagj #ajf #ehb #jagb #ajee #egd #jagd #aje #efg #jagf #ajd #eeb #jahb #ajce #ede #jahc #ajc #ech #jahf #ajbe #eca #jahh #ajb #ebe #jaij #ajae #eah #jaic #aja #eab #jaie #ajje #ejf #jaih #ajj #ejj #jbjj #iie #did #jbjb #ii #dhh #jbje #ihe #dhb #jbjg #ih #dgg #jbji #ige #dga #jbab #ig #dff #jbae #ife #dfa #jbag #if #dee #jbbj #iee #dej #jbbb #ie #dde #jbbd #ide #ddj #jbbg #id #dcf #jbcj #ice #dca #jbcb #ic #dbf #jbce #ibe #dbb #jbcg #ib #dag #jbdj #iae #dac #jbdb #ia #djh #jbde #ije #djd #jbdg #ij #djj #jbej #hie #cif #jbec #hi #cib #jbee #hhe #chh #jbeh #hh #chd #jbfj #hge #chj #jbfc #hg #cgf #jbff #hfe #cgb #jbfi #hf #cfi #jbga #hee #cfe #jbgd #he #cfb #jbgf #hde #ceh #jbgi #hd #ced #jbhb #hae #cch #jbif #ha #cce #jbii #hje #cca #jcjb #hj #cbh #jcjd #gie #cbe #jcjg #gi #cbb #jcaj #ghe #cai #jcac #gh #cag #jcaf #gge #cad #jcai #gg #caa #jcbb #gfe #cjh #jcbe #gf #cje #jcbg #gee #cjc #jccj #ge #cjj #jccc #gde #bigc #jccf #gd #bidg #jcci #gce #biba #jcdb #gc #bhif #jcde #gbe #bhga #jcdh #gb #bhdf #jcea #gae #bhbb #jced #ga #bgig #jceg #gje #bggc #jcfj #gj #bgej #jcfd #fie #bgbf #jcfg #fi #bgjc #jcgj #fhe #bfhj #jcgc #fh #bfeh #jcgf #fge #bfcf #jcgi #fg #bfad #jchb #ffe #beib #jchf #ff #bega #jchi #fee #beej #jcib #fe #bebi #jcie #fde #beji #jcih #fd #bdhh #jdjb #fce #bdfh #jdje #fc #bddh #jdjh #fbe #bdbh #jdab #fb #bdji #jdae #fae #bchi #jdah #ei #bbif #jdce #ehe #bbgh #jdci #eh #bbfa #jddb #ege #bbdc #jddf #eg #bbbf #jddi #efe #bbjh #jdec #ef #baia #jdef #eee #bagd #jdfj #ee #baeh #jdfc #ede #bada #jdfg #ed #babe #jdga #ece #baji #jdgd #ec #bjic #jdgh #ebe #bjgg #jdha #eb #bjfa #jdhe #eae #bjde #jdhi #ea #bjcj #jdib #eje #bjae #jdif #ej #bjjj #jejj #die #aihe #jejd #di #aigj #jejh #dhe #aiee #jeaa #dh #aida #jeae #dge #aibf #jeai #dg #aiac #jebc #dfe #ahih #jebg #df #ahhd #jeca #dee #ahgj #jece #de #aheg #jech #dde #ahdc #jedb #dd #ahcj #jedf #dce #ahaf #jeej #dc #ahjc #jeed #dbe #agij #jeeh #db #aggg #jefb #dae #agfe #jefg #da #ageb #jega #dje #agci #jege #dj #agbg #jegi #cie #agad #jehc #ci #agjb #jehg #cfe #afdc #jfji #cf #afca #jfac #cee #afbj #jfag #ce #afjh #jfbb #cde #aeig #jfbf #cd #aehf #jfcj #cce #aege #jfce #cc #aefd #jfci #cbe #aeec #jfdd #cb #aedb #jfdh #cae #aeca #jfec #ca #aeba #jfeg #cje #aeaj #jffb #cj #aejj #jffg #bie #adhi #jfga #bi #adgi #jfgf #bhe #adfi #jfha #bh #adei #jfhe #bge #addi #jfij #bg #adci #jfie #bfe #adbi #jgjj #bf #adai #jgje #bee #adji #jgji #be #adjj #jgad #bde #acij #jgai #bd #achj #jgbd #bce #acga #jgbi #bc #acfb #jgcd #bbe #aceb #jgci #bb #acdc #jgdd #bae #accd #jgdi #ba #acbe #jged #bje #acaf #jgfj #bj #acjg #jgfe #aie #abih #jggj #ai #abij #jgge #ahe #abha #jghj #ah #abgb #jghf #age #abfd #jgia #ag #abee #jgif #afe #abdg #jhjb #af #abch #jhjg #aee #abcj #jhac #ae #abbb #jhah #ade #abad #jhbc #ad #abjf #jhbi #ace #aaih #jhce #ac #aahi #jhda #abe #aaha #jhdg #ab #aagc #jheb #aae #aaff #jheh #aa #aaeh #jhfc #aje #aaej #jhfi #aj #aadc #jhge #ie #aace #jhha #i #aabg #jhhg #he #aabj #jhic #h #aaab #jhii #ge #aaje #jije #g #ajig #jiaa #fe #ajij #jiag #f #ajhc #jibc #ee #ajgf #jibi #e #ajfh #jice #de #ajfa #jidb #d #ajed #jidh #ce #ajdg #jied #c #ajdj #jifj #be #ajcc #jifg #b #ajbg #jigd #ae #ajbj #jihj #a #ajac #jihg #je #ajjf #jiic --------------------------------- ,a ,,synopsis ,,of ,,the ,,principal ,,events ,,that ,,have ,,occurred ,,in ,,connection ,,with ,,the ,,history ,,of ,,the ,,torpedo4 ---------------------------------------- ---------------------------------------- -------------- ,date4 ,operator1 c4 ,event4 ,place4 ,remarks4 ---------------------------------------- ---------------------------------------- -------------- #aehe4 ,italian ,attack on a bridge formed ,antwerp4 ,bridge completely destroyed4 ,engineer1 over the ,scheldt4 ,vessels1 each carrying a heavily ,zambelli4 charged magazine1 fired by clockwork1 were carried by the stream against the bridge4 #agge4 ,captain ,d4 ,numerous small experiments ,america4 ,by which he proved that a charge ,bushnell4 with gunpowder charges4 of gunpowder could be fired under water4 #aggf4 ,attack on the ,english ,new ,york4 ,boat managed by ,sergeant ,e4 ,lee4 frigate ,h4,m4,s4 ,eagle by ,attack failed1 owing to his his submarine torpedo inexperience in manipulating boat4 this novel kind of craft4 #aggg4 ,attack on the ,english ,new ,london4,drifting torpedoes employed4 man-of-war ,h4,m4,s4 ,crew of a prize schooner astern ,cerberus by his of the ,cerberus hauled one of drifting torpedoes4 the torpedoes on board1 which exploded1 killing #c men and destroying a boat4 #aggg4 ,attack on ,english ships by ,this failed1 owing to the ships numerous floating having previously hauled into torpedoes4 ,known by the dock to avoid the ice1 but it name of ,battle of ,kegs4 created a great amount of confusion and alarm among the crews of the vessels4 #agig4 ,r4 ,fulton4 ,experiments with torpedoes ,france4 ,these first attempts were on the ,seine4 generally failures4 ,july #c1 ,experiments with his ,brest1 ,these experiments were successful #ahja4 submarine boat named the ,france4 in so far as proving that with ,nautilus4 such a boat he could descend to any given depth and reascend to the surface at will1 and that he could remain below for a considerable time4 ,august ,attempted to sink a small ,completely successful4 ,this is #ahja4 vessel by means of one of the first vessel known to be his torpedoes4 destroyed by means of a torpedo4 ,charge of submarine mine #bj lbs4 gunpowder4 #ahja4 ,attempted to destroy one ,off ,owing to the ship altering her of the ,english channel ,boulogne1 position at the moment of fleet by means of his ,france4 setting the torpedo adrift1 this drifting torpedoes4 attack failed4 ,oct4 #c1 ,catamarran expedition under ,boulogne1 ,failed1 owing to a mistake in the #ahjd4 ,lord ,keith to destroy the ,france4 construction of the torpedoes4 ,french fleet4 ,the mines exploded1 but did no damage to the ,french ships4 ,oct4 ,similar expedition4 ,similar failure1 owing to causes #ahje4 above mentioned4 ,oct4 #ae1 ,attempted to destroy a brig ,dover1 ,the brig was completely #ahje4 ,dorothea with his ,england4 demolished4 ,two torpedoes drifting torpedoes4 employed1 each charged with #ahj lbs4 gunpowder and fired by clockwork4 ,july #bj1 ,experiment on a large hulk ,new ,york1 ,finally successful1 several #ahjg4 brig4 ,america4 attempts being necessary1 owing to faulty construction4 ,oct4 ,attack on the ,u4,s4 sloop ,new ,york4 ,failed1 owing to the very #ahaj4 ,argus for finally ingenious though elaborate testing the efficacy of defence of the vessel1 carried his torpedo schemes4 out under the directions of ,commodore ,rodgers4 #ahab4 ,mr4 ,mix4 ,attack on the ,english ,lynn1 ,haven,complete failure1 though six frigate ,h4,m4,s4 ,bay1 different attempts were made4 ,plantagenet with his ,america4 drifting torpedoes4 ,june #ae1 ,attack on ,h4,m4,s4 ,ramilies ,new ,york4 ,an utter failure4 #ahac4 by blowing up a schooner alongside4 #ahbj4 ,captain ,experiment with a submarine ,moulsford1 ,idea was to fasten the torpedo by ,johnson4 boat carrying a torpedo ,berks1 means of screws to the bottom of on its back4 ,england4 the hostile vessel4 ,trial proved successful1 but the ,english government refused to sanction the project as being too diabolical4 ,july #d1 ,colonel ,experiment on a raft with ,ware ,pond1 ,successful4 #ahbi4 ,samuel his submarine battery4 ,america4 ,colt4 #ahci4 ,general ,destruction of the wreck ,portsmouth1,he is stated to have employed ,paisley1 of the ,royal ,george by ,england4 galvanic firing to explode the ,r4,e4 submarine mines4 mines4 #ahdj4 ,captain ,experiment on the ,john ,england4 ,successful4 ,details not known4 ,warner4 ,o',gaunt4 ,june #d1 ,colonel ,s4 ,experiment to explode a ,new ,york4 ,successful4 ,the operator was at a #ahdb4 ,colt4 submarine mine by great distance from the torpedo4 electricity4 ,july #d1 ,experiment on the ,u4,s4 ,castle ,successful4 ,the operator was on #ahdb4 gunboat ,boxer with ,garden1 board ,u4,s4 man-of-war at some electric submarine mines4 ,new ,york4 distance from the place where the explosion occurred4 ,aug4 #bj1 ,colonel ,s4 ,similar experiment on a ,potomac ,successful1 the operator being #ahdb4 ,colt4 schooner4 ,river1 stationed at a distance of #e ,america4 miles from where the mine was placed4 ,oct4 #ah1 ,similar experiment on the ,new ,york4 ,successful4 ,the operator being on #ahdb4 brig ,volta1 #cjj tons4 board the revenue cutter ,ewing1 at a considerable distance from the scene of the explosion4 ,april #ac1 ,experiment to destroy a ,potomac ,successful4 ,the vessel was1 at #ahdc4 vessel of #ejj tons under ,river1 the time of the explosion1 weigh by electric ,america4 sailing at the rate of #e knots submarine mines4 per hour1 and to prevent the possibility of any collusion between the operator and crew1 they left the ship a few moments before the catastrophe4 ,operator #e miles distant4 ,probably several mines were placed in the form of a circle4 ,july1 ,captain ,experiment with his ,brighton1 ,the vessel completely destroyed4 #ahdd4 ,warner4 invisible shell1 on a ,england4 barque of #dej tons4 ,jan4 #a1 ,colonel ,s4 ,experiment with an electric ,new ,york4 ,successful4 ,the operator being at #ahde4 ,colt4 submarine mine4 a distance of #dj miles from where the explosion took place4 #ahdf4 ,professor ,discovered the explosive 44 ,brought into use for military ,schonbein4 agent gun-cotton4 purposes about #ahfc1 by ,professor ,abel4 #ahdf4 ,sobrero4 ,discovered the explosive 44 ,brought into use about #ahfc1 for agent nitro-glycerine4 blasting purposes by ,m4 ,alfred ,nobel1 a ,swede4 #ahed4 ,russians4 ,attempted destruction of ,cronstadt4 ,several torpedoes were exploded the ,english men-of-war near these ships1 but with no ,merlin and ,firefly1 other results than a wetting to by stationary submarine some of their men4 mines4 ,feb4 #ah1 ,confederates4,federal gunboats attempting ,america4 ,considerably delayed1 caused by #ahfb4 to force the ,savannah the submarine mines1 but no river4 actual damage done4 ,this was their first appearance in a practical form during the civil war4 ,dec4 #ac1 ,destruction of the ,federal,yazoo ,river1,two torpedoes exploded under her2 #ahfb4 ironclad ,cairo1 by ,america4 vessel much shattered1 and sunk stationary torpedoes4 in #ab minutes4 ,first vessel destroyed in this war4 ,feb4 #bh1 ,the ,federal monitor ,ogeechee ,she was saved from sinking by #ahfc4 ,montauk1 severely ,river1 being run on the mud1 thus damaged by a submarine ,georgia4 enabling the hole to be mine4 temporarily closed1 and the vessel taken to ,port ,royal4 ,july #bb1 ,the ,federal ironclad ,yazoo ,river4,the vessel went down in #ae #ahfc4 gunboat ,baron de ,kalb1 minutes4 ,as she was sinking a sunk by a submarine mine4 second torpedo exploded under her stern4 ,no lives were lost4 ,aug4 #h1 ,the ,federal gunboat ,james ,river4,the ship was1 at the time of the #ahfc4 ,commodore ,barney explosion1 steaming #i knots1 and severely damaged4 ran into it1 losing #bj men1 and being some what severely damaged4 ,it was an electric submarine mine charged with #agej lbs4 gunpowder4 ,oct4 #e1 ,boat torpedo attack on the ,charleston4,failed4 ,it was made by a boat #ahfc4 ,federal ship ,ironsides4 armed with a spar torpedo with #fj lbs4 gunpowder4 #ahfc4 ,confederate steamers ,owing to the shifting of the ,marion and ,ettiwa position of barrel torpedoes4 destroyed by their own mines4 #ahfc4 ,confederate flag of truce ,james ,river4 ,the same cause4 boat ,shultz4 ,feb4 #ag1 ,boat torpedo attack on the,charleston4 ,successful1 the ship being sunk4 #ahfd4 ,federal frigate ,a submarine boat was employed on ,housatonic4 this occasion1 and owing to her running into the hole made by her torpedo1 went down with the ship4 ,march #f1 ,boat torpedo attack on the,north ,edisto,failed1 owing to the torpedo spar #ahfd4 ,federal ship ,memphis4 ,river1 ,south being broken by the vessel's ,carolina4 screw4 ,april #a1 ,destruction of the ,federal ,st4 ,john's ,this was effected by a floating #ahfd4 transport ,maple ,leaf4 ,river1 torpedo4 ,florida4 ,april #i1 ,boat torpedo attack on the,james ,river4,the ship was severely damaged1 #ahfd4 ,federal ship ,minnesota4 but not sunk4 ,spar torpedo1 charge #ec lbs4 gunpowder4 ,april #ai1 ,boat torpedo attack on the,charleston4 ,failed1 owing to the boat being #ahfd4 ,federal frigate ,wabash4 discovered4 ,may #f1 ,loss of the ,commodore ,james ,river4,completely demolished by an #ahfd4 ,jones4 electric torpedo1 #agej lbs4 gunpowder4 ,this part of the river having been carefully dragged4 ,aug4 #e1 ,confederates4,loss of the ,federal monitor ,mobile ,bay4,this occurred during the ,federal #ahfd4 ,tecumseh4 attack on the defences of ,mobile ,bay1 the ship disappearing almost instantaneously4 ,the captain and #gj of the crew were killed4 ,oct4 #bg1 ,federals4 ,boat torpedo attack on the ,near ,the only ,federal torpedo success #ahfd4 ,confederate ironclad ,plymouth1 during the war4 ,the boat was ,albemarle4 ,america4 armed with the ,wood and ,lay disconnecting spar torpedo4 ,the ship was sunk4 ,dec4 #i1 ,confederates4 ,loss of the ,federal ,roanoke ,the latter vessel was proceeding #ahfd4 steamers ,otsego and ,river4 to the assistance of the former4 ,bazeby4 ,both were totally destroyed4 #ahfd4 ,m4 ,a4 ,nobel4 ,introduction of dynamite4 44 ,a modified form of the explosive nitro-glycerine4 #ahfd4 ,captain ,first series of experiments ,fiume1 ,the idea of such a weapon ,lupuis and with the fish torpedo4 ,austria4 previously known1 but not acted ,mr4 on4 ,whitehead4 ,jan4 #ae1 ,confederates4,loss of the ,federal monitor,charleston4 ,completely destroyed by a barrel #ahfe4 ,patapsco4 torpedo1 sinking in a few minutes4 ,sixty-two officers and men drowned4 ,march #a1 ,loss of the ,federal steamer,near ,the place where this catastrophe #ahfe4 ,harvest ,moon4 ,georgetown4 occurred had been previously swept for torpedoes4 ,march #cj ,loss of two ,federal ,mobile ,bay4 ,these losses occurred in the to ,april1 monitors1 and three final attack on ,mobile1 at the #ai #ahfe4 gunboats4 close of the war4 ,sept4 #b1 ,paraguayans4 ,loss of the ,brazilian war ,currupaity1 ,completely destroyed by a #ahff4 steamer ,rio ,janeiro4 ,paraguay4 stationary torpedo at the bombardment of ,currupaity by the ,brazilian fleet4 #ahgd4 ,england4 ,adoption of the electric light in the ,navy4 ,may #bi1 ,english4 ,torpedo attack by ,h4,m4,s4 44 ,this is the first ,whitehead fish #ahgg4 ,shah on the ,peruvian torpedo ever fired against an ironclad ,huascar4 hostile ship4 ,it failed1 owing to the ,huascar being at too great a distance4 ,may #ab1 ,russians4 ,russian torpedo boat attack ,batoum4 ,failed4 ,a ,turkish ship was struck #ahgg4 on several ,turkish ships4 by a towing torpedo1 but it failed to explode4 ,may #bf1 ,russian torpedo boat ,matchines1 ,successful4 ,a ,turkish monitor1 #ahgg4 attack on the ,turkish ,river ,duba ,saife1 was sunk4 ships ,fettu ,islam1 ,danube4 ,duba ,saife1 and ,kilidj ,ali4 ,june #i1 ,russian torpedo boat ,sulina1 ,failed4 ,the ,russian torpedo boat #ahgg4 attack on the ,turkish mouth of ,no4 #a was sunk1 and her ironclads ,feteh ,bulend1 the commander1 ,lieutenant ,poutschin1 ,moocardemikhair1 and ,danube4 with his crew1 taken prisoner4 ,idglalieh4 ,the attack was made by six boats4 ,june #bj1 ,turkish monitor attacked ,rutschuk1 on,failed4 ,the officer in command of #ahgg4 by the ,russian spar the ,danube4 the boat being severely wounded1 torpedo boat,choutka4 and the torpedo wires cut4 ,this attack was made in the daytime4 ,june #bc1 ,two ,russian torpedo boats ,mouth of the,failed1 owing to the spirited #ahgg4 attacked a ,turkish ,aluta1 defence on the part of the monitor4 ,danube4 ,turks4 ,another day affair4 ,aug4 #bb1 ,the ,turkish ironclad ,soukoum ,failed4 ,the captain of the #ahgg4 ,assari ,shefket attacked ,kaleh4 ,assari ,shefket had placed by four ,russian torpedo guard boats in advance of his boats4 ship1 by which he was warned of the approach of the torpedo boats1 and so enabled to foil the attack by a well-directed1 hot fire4 ,oct4 #aj1 ,loss of ,turkish gunboat ,sulina4 ,the gunboat was sunk by striking #ahgg4 ,suna at the ,russian an electro-contactmine1 placed attack on ,sulina4 by the ,russians about #c_/d mile above the ,turkish defences4 ,about fifteen officers and men killed and wounded4 ,dec4 #bg1 ,turkish squadron attacked ,batoum4 ,failed4 ,the ,russians fired two #ahgg4 by four ,russian torpedo ,whitehead fish torpedoes 7the boats1 two being armed first attack of this nature with the ,whitehead fish during the war71 both of which torpedo4 were picked up by the ,turks4 ,jan4 #be1 ,attack on ,turkish ships by ,batoum4 ,successful4 ,a ,turkish revenue #ahgh4 two ,russian torpedo boats1 steamer on guard being sunk4 armed with the ,whitehead ,final torpedo attack made in the fish torpedo4 ,russo-,turkish war 7#ahgg-gh74 ---------------------------------------- ---------------------------------------- -------------- ,,footnotes3 ,footnote ,y3 ,see page #ib4 ,,errata4 ,on ,page #g 7line #aa7 insert words could be destroyed after anchor4 ,on ,page #bhd1 7,middle of page7 ,fig4 #agf should be ,fig4 #afh4 ,on ,page #bhe 7#dth line from bottom7 e should be d4 ,,index4 ,a4 ,abel1 experiments by ,professor1 #bjg ,abel's detonation experiments1 #baf ---- high tension fuzes1 #cg ---- mechanical primer1 #bc ,action1 chemical1 #bfi ---- ----1 in a ,daniell cell1 #bgd ---- ---- single fluid cell1 #bgc ,adjustments of ,whitehead's fish torpedo1 the1 #acf ,admiral ,porter's torpedo ship ,alarm1 #aei ---- ----1 the armament of1 #afj ,adoption of the fish torpedo1 the invention and1 #aca ,advantages of electrical submarine mines1 the1 #bh ---- ---- mechanical mines1 the1 #ag ,agents1 torpedo explosive1 #bag ,air pump1 the1 #bfj ,alarm1 ,admiral ,porter's torpedo ship1 #aei ,albemarle1 destruction of the1 #aia ,aluta1 the ,russian torpedo boat attack off the1 #bjj ,american ,civil ,war1 the1 #ahi ---- ----1 mechanical mines in the1 #af ---- ----1 torpedoes during the1 #aae ---- ----1 submarine mines during the1 #bg ---- extempore drifting torpedoes1 #aai ,apparatus1 directions for using the diving1 #bfa ----1 firing keys and shutter1 #hj ----1 ,siemens' electric light1 #bda ---- ----1 conducting wires for1 #bdg ---- ----1 rotation of armatures in1 #bdf ---- ----1 wear and tear of1 #bdg ----1 the shutter1 #hb ---- used with a circuit breaker1 shutter1 #hc ,application of ,ohm's law1 the1 #bgf ---- ---- the electric light1 the1 #bef ,arcs1 firing by intersectional1 #ga ,argus1 ,fulton's attempt against the1 #f ,armatures in ,siemens' electric light apparatus1 rotation of1 #bdf ,armoured cables1 single cored1 #dc ,armstrong's system of electrical testing1 #ajg ,arrangement of earth plates1 ,brown's1 #ajj ---- ---- wires in ,mc,evoy's spar torpedo1 #aee ,arrangements1 ,steward's safety cock1 #be ,astatic galvanometer1 the1 #hg ,attack with ,harvey's torpedoes1 methods of1 #abg ,attacks1 boat torpedo1 #aia ---- ----1 methods of protecting ships against1 #ahj ,austrian method of mooring1 the1 #ef ---- ---- testing1 the1 #aji ---- self-acting circuit closers1 #fd ---- testing table1 the1 #ajh ---- torpedo experiments1 #bbj ---- ---- launches1 ,thornycroft's1 #afe ---- war1 torpedo operations during the1 #aib ,austro-,italian war1 torpedo operations during the1 #ahh ,automatic arrangements1 #aj ---- electric lamps1 #bdh ,b4 ,balance1 ,wheatstone's1 #ig ---- ----1 manipulation of1 #ii ---- ----1 measurement of resistances by1 #ih ,barrel torpedoes1 #ai ,batoum1 ,russian torpedo boat attack at1 #aie1 #bjb ,batteries1 bichromate1 #gg ----1 double fluid1 #bgd ----1 firing1 #ge ,batteries1 ,leclanch's ,voltaic1 #gg ----1 ,menotti test1 #gi ----1 signalling1 #gh ---- ----1 ,daniell's1 #gh ----1 single and double fluid1 #bgb ----1 telegraph1 #gi ----1 ,voltaic1 #gi ----1 ,von ,ebner's1 #gf ,battery test for electro-motive force1 ,voltaic1 #aje ---- ---- internal resistance1 ,voltaic1 #ajd ---- ---- potential1 ,voltaic1 #ajd ,beardslee's high tension fuze1 #cf ---- joint1 #df ,bearings1 firing by cross1 #gj ,bichromate batteries1 #gg ,boat1 ,bushnell's submarine1 #b1 #ahd ----1 ,confederate submarine1 #ahe ----1 experiment at ,cherbourg1 torpedo1 #agj ----1 ,french submarine1 a1 #ahe ----1 ,lay torpedo1 the1 #ada ---- ----1 capabilities of the1 #adg ---- ----1 clearing obstructions with the1 #aea ---- ----1 improved form of the1 #aec ---- ----1 launching the1 #adg ---- ----1 method of sinking and raising the1 #adi ---- ----1 used as a tug1 #aej ---- ---- to clear away mines1 #aeb ----1 ,lightning1 ,thornycroft's torpedo1 #afh ----1 torpedo1 attack at ,batoum1 #aie1 #bjb ---- ---- ,rustchuk1 #bjj ---- ---- ,soukoum ,kaleh1 #bja ---- ---- ,soulina1 #aih ---- ---- off ,matchin1 #aif ---- ---- the ,aluta1 #bjj ---- ----1 the final1 #bjc ---- ----1 attacks1 #ahj1 #aia ---- ----1 methods of protecting ships against1 #ahj ---- ----1 protective1 ,fosberry's patent1 #ahb ,boats1 submarine1 #ahc ---- ----1 qualifications essential to1 #ahd ----1 torpedo1 #afb ---- ----1 ,english1 #agc ---- ----1 ,herreshoff's1 #agh ---- ----1 ordinary type of1 #agi ---- ----1 ,schibau's ,russian1 #agh ---- ----1 ,spanish1 #age ---- ----1 ,thornycroft's1 #afc ---- ----1 ,yarrow's1 #agb ,booms1 construction of1 #aaj ----1 defence of harbours by1 #aaj ,boots for divers1 #bfa ,boxes1 junction1 #ea ---- ----1 for multiple cables1 #eb ---- ---- single cored cables1 #eb ----1 resistance1 #ig ,brakes for ,harvey's torpedoes1 #abc ,breaker1 the circuit1 #fb ,breast-plate for divers1 #bfj ,brook's torpedoes1 #ai ,brown's arrangement of earth plates1 #ajj ,buoys for ,harvey's torpedoes1 #abb ,bushnell1 the inventor of torpedoes1 #b ,bushnell's drifting torpedoes1 #b ---- mode of ignition1 #b ---- submarine boat1 #b1 #ahd ,c4 ,cable1 ,colt's electric1 #g ---- cutters1 ,fulton's1 #e ,cables1 circuit closer1 #db ----1 creeping for electric1 #aab ----1 defects observed in the conductivity of1 #ajc ----1 ,hooper's1 #da ----1 insulated electric1 #ch ----1 insulation test for electric1 #ajb ----1 jointing electric1 #dd ----1 junction boxes for multiple1 #eb ---- ---- single cored1 #eb ----1 land service1 #dc ----1 multiple1 #db ----1 sea service1 #dc ----1 ,siemens' electric1 #dj ----1 ,silvertown electric1 #da ----1 single cored armoured1 #db ---- ---- unarmoured1 #dc ----1 special1 #dc ----1 test of electrical resistance of1 #ajd ,cairo1 the loss of the1 #ahi ,calland and ,mari-,davy batteries1 description of the1 #bge ,capabilities of ,lay's torpedo boat1 #adg ---- ---- ,whitehead's fish torpedo1 #acd ,carlscrona1 experiments with countermines at1 #bcg ----1 torpedo experiments at1 #bbj1 #bbd1 #bcb ,case1 conical-shaped torpedo1 #cb ----1 cylindrical-shaped torpedo1 #cb ----1 form and construction of torpedo1 #ca ----1 spherical-shaped torpedo1 #cb ,cell1 action in a single fluid1 #bgc ----1 chemical action of a ,daniell1 #bgd ----1 definition and properties of a ,voltaic1 #bfi ----1 description of a ,menotti1 #gh ----1 tests for insulation1 sea1 #ajf ---- ----1 sea1 #ajj ,charges1 size of torpedo1 #bah ,chatham1 torpedo experiments at1 #bbj ,chemical action1 #bfi ---- fuzes1 #bc ---- ----1 defects of1 #bd ,cherbourg1 torpedo boat experiment at1 #agj ,circuit breakers1 #fb ---- closer cables1 #dc ---- closers1 ,austrian self-acting1 #fd ---- ----1 electro-contact mine1 #fc ---- ----1 ,mathieson's inertia1 #fa ---- ----1 improvements in1 #fc ---- ---- spiral spring1 #fc ---- ----1 ,mc,evoy's mercury1 #fe ---- ---- weight magneto1 #ff ---- ----1 the use of1 #fj ----1 closing the electric1 #fj ---- resistances1 #bgf ----1 short1 #bfh ----1 the electric1 #bfg ,civil war1 torpedo operations during the ,american1 #ahi ----1 torpedoes in the ,american1 #aae ,clearing a passage through torpedo defences1 #aaa ,coil galvanometer1 the three1 #hh ,colt1 experiments by ,colonel1 #g ,colt's electric cable1 #g ---- reflector1 #g ,commodore ,jones1 the loss of the1 #ahi ,commutators or switch plates1 #if ,comparing electro-motive forces1 #id ,composition1 ,rain's detonating1 #bc ,compounds1 explosive1 #bjh ,concentration of the electric light1 #bea ,condenser1 definition of a1 #bgi ,conductivity of cables1 defects observed in the1 #ajc ----1 test of platinum wire fuze for1 #aja ,conductors1 #bff ,confederate submarine boat1 #ahe ,connections of switch plates1 #ajj ,construction of booms1 #aaj ---- ---- torpedo case1 #ca ,copenhagen1 torpedo experiments at1 #bbc ,countermining1 #aab ,countermines1 experiments with1 #bce ---- ---- at ,carlscrona1 #bcg ---- ---- ,stokes ,bay1 #bcf ---- ---- in the ,medway1 #bcf ,coupling dynamo-electric machines1 methods of1 #bed ,creeping for electric cables1 #aab ,crimean war1 submarine mines during the1 #bg ---- ----1 torpedo operations during the1 #ahg ,crinoline for divers1 #bfa ,cross bearings1 firing by1 #gj ,current1 direction of1 #bgb ----1 measuring the intensity of a1 #ie ----1 the ,voltaic1 #bgj ,d4 ,daniell's signalling battery1 #gh ,defects observed in the conductivity of cables1 #ajc ---- of chemical fuses1 #bd ---- electrical submarine mines1 #bi ,defence of harbours by booms1 #aaj ----1 ship1 #aj ,defences1 clearing a passage through torpedo1 #aaa ,defensive purposes1 ,harvey's torpedo for1 #abi ---- torpedo operations1 ,russian1 #aic ---- ----1 ,turkish1 #aic ---- ---- warfare1 #ac ,definition and properties of a ,voltaic cell1 #bfi ---- of a condenser1 #bgi ---- potential1 #bgj ---- the ohm1 #bha ---- ---- term explosion1 #bjd ---- ---- explosive force1 #bjd ---- ---- polarization1 #bgc ,description of a frictional electric machine1 #bgh ---- ---- series of firing keys1 #ha ---- ---- ,yarrow's torpedo boat1 #agb ---- ---- ,calland's and ,mari-,davy's batteries1 #bge ---- ---- ,siemens' electric light apparatus1 #bda ---- ---- ,whitehead's fish torpedo1 #acc ,destroyer1 ,ericsson's torpedo vessel1 #afj ,destruction of passive obstructions1 the1 #aac ---- ---- the ,albemarle1 #aia ---- ---- ,duba ,saife1 #aig ---- ---- ,suna1 #aid ,detector galvanometer1 the1 #hh ,detonating composition1 ,rain's1 #bc ,detonation1 #bjf ---- experiments1 ,abel's1 #baf ----1 theory of1 #bjf ,dielectric1 gutta percha as a1 #ch ----1 meaning of1 #bgi ,differential galvanometer1 the1 #hh ,direction of current1 #bgb ,directions for using the diving apparatus1 #bfa ,discharge test1 the1 #ajc ,disconnector1 the1 #ec ,diver1 dressing the1 #bfb ,divers1 boots for1 #bfa ----1 breast plate for1 #bfj ----1 crinoline for1 #bfa ----1 helmet for1 #bfj ----1 ladder for1 #bfj ,diving1 #bei ---- dress1 the1 #bfj ----1 signals employed in1 #bfc ,dorothea1 ,fulton's destruction of the1 #d ,double fluid batteries1 #bgd ---- ----1 single and1 #bgb ,drifting torpedoes1 #aaf ---- ----1 ,american extempore1 #aai ---- ----1 ,bushnell's1 #b ---- ----1 ,fulton's1 #e ---- ----1 ,lewis's1 #aag ---- ----1 ,mc,evoy's1 #aah ,dualin1 #baf ,duba ,saife1 destruction of the1 #aig ,duplex spar torpedo1 ,mc,evoy's1 #aed ---- ----1 arrangement of wires in1 #aee ,dutch torpedo launches1 ,thornycroft's1 #afh ---- ----1 ,yarrow's1 #agb ,dynamite1 #baa ,dynamo-electric machines1 methods of coupling1 #bed ---- machine1 ,siemens' low tension1 #ge ,e4 ,earth plates1 ,browne's arrangement of1 #ajj ,effect compared1 explosive force and1 #bjd ,efficiency of ,thornycroft's boat engines1 #aga ,electric cables1 creeping for1 #aab ---- ----1 ,hooper's1 #da ---- ----1 insulated1 #ch ---- ----1 insulation test for1 #ajb ---- ----1 jointing1 #dd ---- ----1 ,siemens'1 #dj ---- ----1 ,silvertown1 #da ---- circuit1 closing the1 #fj ,electric circuit1 the1 #bfg ---- fuses1 #cc ---- lamps1 automatic1 #bdh ---- ----1 ,siemens' patent1 #bdh ---- light apparatus1 ,siemens'1 #bda ---- ----1 conducting wires for1 #bdg ---- ----1 light produced by1 #bdd ---- ----1 rotation of armatures in1 #bdf ---- ----1 wear and tear of1 #bdg ---- ----1 application of the1 #bef ---- ----1 concentration of the1 #bea ---- ----1 precautions in manipulating1 #beb ---- ----1 self-acting shunt for ,siemens'1 #bde ---- ----1 the1 #bci ---- machine1 description of a frictional1 #bgh ---- machines1 methods of coupling dynamo1 #bed ,electrical resistance of cables1 test of the1 #ajd ---- resistances1 measuring1 #ic ---- submarine mines1 #aj1 #bg ---- ----1 advantages of1 #bh ---- ----1 defects of1 #bb ---- ----1 mooring1 #ed ---- ----1 rules for using1 #bi ---- test of insulated joints1 #ajd ---- testing1 ,armstrong's system of1 #ajg ---- tests1 #he ,electricity1 frictional1 #bgh ----1 methods of generating1 #bfi ----1 theory of1 #bfe ,electro-contact mines1 circuit closers for1 #fc ,electrolytes1 #bga ,electro-positive and electro-negative1 the terms1 #bga ,electro-magnet1 the1 #bha ,electro-mechanical mines1 ,russian1 #fh ,electrometers1 #hf ----1 ,thomson's quadrant1 #hf ,electro-motive force1 #bgj ---- ----1 ,voltaic battery test for1 #aje ---- forces1 comparing1 #id ,employment of torpedo ships1 the1 #aeh ,engines1 efficiency of ,thornycroft's boat1 #aga ,england1 torpedo experiments in1 #bbb ,english service platinum wire fuse1 the1 #cc ---- torpedo boats1 ,yarrow's1 #agc ,ericsson's torpedo vessel ,destroyer1 #afj ,experiment at ,cherbourg1 torpedo boat1 #agj ---- with a torpedo boat1 flotation1 #aga ,experiments1 ,abel's detonation1 #baf ---- by ,professor ,abel1 #bjg ---- ---- ,roux and ,sarrau1 #bjg ----1 ,colt's torpedo1 #g ----1 ,fulton's practical1 #e ----1 torpedo1 at ,carlscrona1 #bbj1 #bbd1 #bcb ---- ---- ,chatham1 #bbj ---- ---- ,copenhagen1 #bbc ---- ---- ,kiel1 #bbb ---- ---- ,pola1 #bca ---- ---- ,portsmouth1 #bbi1 #bcc ---- ----1 ,fulton's ,french1 #c ---- ----1 in ,austria1 #bbj ---- ---- ,england1 #bbb ---- ---- ,turkey1 #bcb ---- with countermines1 #bce ---- ---- at ,carlscrona1 #bcg ---- ---- ,stokes ,bay1 #bcf ---- ---- in the ,medway1 #bcf ,explosion1 definition of the term1 #bjd ,explosive agents1 torpedo1 #bag ---- compounds1 #bjh ---- force and effect compared1 #bjd ---- ----1 definition of the term1 #bjd ---- mixtures1 #bjh ---- substance1 physical state of the1 #bjd ,explosions1 illustrated torpedo1 #bah ,extempore drifting torpedoes1 ,american1 #aai ---- high tension fuzes1 #cg ---- ----1 ,fisher's1 #cg ---- mechanical mine1 #ba ,f4 ,failure of offensive torpedoes1 the1 #h ,fastest vessel in the world1 the1 #agg ,final ,russian torpedo boat attack1 the1 #bjc ,firing batteries1 #ge ---- by cross bearings1 #gj ---- ---- intersectional arcs1 #ga ---- ---- observation1 #fi ---- ---- preconcerted signal1 #ga ---- ,harvey's torpedoes1 mode of1 #aba ---- keys1 #hj ---- ----1 description of a series of1 #ha ---- ----1 ,morse1 #ha ----1 mode of1 #bje ---- ----1 in #ahbi1 #f ---- ,whitehead torpedoes1 ,thornycroft's method of1 #adj ,fish torpedo1 adjustments of ,whitehead's1 #acf ---- ----1 description of the1 #acc ---- ----1 invention and adoption of the1 #aca ---- ----1 methods of projecting the1 #ach ---- ----1 the mode of ignition of the1 #ace ,fish torpedoes in war1 employment of1 #acc ---- ----1 ,thornycroft's method of firing1 #adj ---- ----1 ,woolwich1 #adj ,fisher's extempore high tension fuze1 #cg ,floating torpedoes1 #aaf ,flotation experiment with a torpedo boat1 #aga ,fluid batteries1 double1 #bgd ---- ----1 single and double1 #bgb ,fluid cell1 action in a single1 #bgc ,force compared1 explosive effect and1 #bjd ----1 definition of the term explosive1 #bjd ----1 electro-motive1 #bgj ----1 ,voltaic battery test for electro-motive1 #aje ,forces1 comparing electro-motive1 #id ,fore and aft mooring1 #ef ,form of ,lay's torpedo boat1 an improved1 #aec ---- ---- torpedo case1 #ca ,fosberry's patent torpedo boat protective1 #ahb ,frame torpedoes1 #ah ,frames1 projecting1 #aaa ,franco-,german war1 torpedo operations during the1 #aib ---- ----1 torpedoes in the1 #ac ,french submarine boat ,plongeur1 #ahe ---- torpedo launches1 ,thornycroft's1 #afe1 #afi ---- towing torpedoes1 #aca ,frictional electric machine1 description of a1 #bgh ---- electricity1 #bgh ,fulminate of mercury1 #bae ,fulton1 ,robert1 #b ,fulton's attempt against the ,argus1 #f ---- block ship1 #e ---- cable cutters1 #e ---- destruction of the ,dorothea1 #d ---- drifting torpedoes1 #e ---- failures1 #b ---- ,french torpedo experiments1 #c ---- harpoon torpedoes1 #e ---- practical experiments1 #e ---- return to ,america1 #d ---- spar torpedoes1 #e ---- stationary submarine mines1 #e ,fuzes1 ,abel's1 #cg ----1 ,beardslee's1 #ce ----1 chemical1 #bc ----1 defects of chemical1 #bd ----1 electric1 #cc ----1 extempore1 #cg ----1 extempore1 ,fisher's1 #cg ---- for conductivity1 test of platinum wire1 #aja ----1 high tension1 #cd ----1 improved form of ,jacobi's1 #bd ----1 ,mc,evoy's percussion1 #bd ----1 percussion1 #bc ----1 platinum wire1 #cc ----1 ----1 ,english service1 #cc ----1 ----1 ,mc,evoy's1 #cd ----1 sensitive1 #bc ----1 ,statham's1 #ce ----1 test of resistance of platinum wire1 #aja ----1 testing high tension1 #ajb ----1 ,von ,ebner's1 #cf ,g4 ,galvanometer1 astatic1 #hg ----1 detector1 #hh ----1 differential1 #hh ----1 tables1 ,siemens' universal1 #bhg ----1 thermo1 #hi ----1 ,thomson's reflecting1 #hg ----1 three coil1 #hh ----1 universal1 ,siemens'1 #hi ,generating electricity1 methods of1 #bfi ,german torpedo vessel ,uhlan1 the1 #aeh ,gun1 the ,nordenfelt torpedo1 #beg ----1 ,hotchkiss torpedo1 #bei ,gun-cotton1 #bab ,gunpowder1 #bjh ,guns1 torpedo1 #beg ,gutta-percha as a dielectric1 #ch ,h4 ,harbours by booms1 defence of1 #aaj ,harpoon torpedoes1 ,fulton's1 #e ,harvey's towing torpedo1 #aai ---- ----1 brakes for1 #abc ---- ----1 buoys for1 #abb ---- ----1 for defensive purposes1 #abi ---- ----1 launching1 #abc ---- ----1 methods of attack with1 #abg ---- ----1 mode of firing1 #aba ---- ----1 tactics with1 #abg ---- ----1 the value of1 #abi ,helmet for divers1 #bfj ,herreshoff's torpedo boats1 #agh ,high tension fuzes1 #ajb ,hooper's electric cables1 #da ---- material1 #ci ,horsley's powder1 #baf ,hotchkiss torpedo gun1 the1 #bei ,i4 ,ignition1 ,bushnell's mode of1 #b ---- of ,whitehead's fish torpedo1 mode of1 #ace ,illustrated torpedo explosions1 #bah ,improved form of ,lay's torpedo1 an1 #aec ,india rubber tube joint1 the1 #de ,inertia circuit closer1 ,mathieson's1 #fa ---- ----1 improvements in1 #fc ,instrument and observing telescope1 shutter1 #hd ,instruments used in testing1 #he ,insulated electric cables1 #ch ---- joints1 electrical test of1 #ajd ,insulation1 sea cell tests for1 #ajf ---- test for electric cables1 #ajb ,insulators1 #bfh ,intensity of a current1 measuring the1 #ie ,internal resistance1 ,voltaic battery test for1 #ajd ,intersectional arcs1 firing by1 #ga ,invention and adoption of the fish torpedo1 the1 #aca ,italian torpedo launches1 ,thornycroft's1 #afh ,j4 ,jacobi's fuze1 improved form of1 #bd ,jar1 the ,leyden1 #bgi ,jointing electric cables1 #dd ,joints1 ,beardslee's1 #df ----1 electrical test of insulated1 #ajd ----1 india rubber tube1 #de ----1 ,mathieson's1 #de ----1 ,mc,evoy's1 #df ----1 ,nicholl's metallic1 #de ----1 rules to be observed in forming1 #ea ----1 ,siemens' permanent1 #dg ,jones1 the loss of the ,commodore1 #ahi ,junction boxes1 #ea ---- ---- for multiple cables1 #eb ---- ---- single cored cables1 #eb ---- ----1 ,t1 #ec ,k4 ,keys1 firing1 #hj ---- ----1 description of a series of1 #ha ---- ----1 ,morse1 #ha ,kiel1 torpedo experiments at1 #bbb ,knowledge1 theoretical1 #h ,l4 ,ladder for divers1 #bfa ---- mooring1 #ee ,lamps1 automatic electric1 #bdh ----1 ,siemens' patent electric1 #bdh ,land service cables1 #dc ,launch1 description of a ,yarrow torpedo1 #agb ---- for placing moorings1 steam1 #eh ,launches1 ,thornycroft's torpedo1 #afc ---- ---- ,austrian and ,french torpedo1 #afe ---- ---- ,dutch and ,italian torpedo1 #afh ---- ---- ,french torpedo1 #afi ---- ---- ,norwegian torpedo1 #afc ---- ---- ,swedish and ,danish torpedo1 #afe ----1 ,yarrow's ,dutch torpedo1 #agc ---- ---- ,russian torpedo1 #agb ,launching ,harvey's torpedo1 mode of1 #abc ---- ,lay's torpedo boat1 #adg ,law1 the application of ,ohm's1 #bgf ,lay's torpedo boat1 #ada ---- ----1 an improved form of1 #aec ---- ----1 capabilities of1 #adg ---- ----1 launching1 #adg ---- ----1 method of sinking and raising1 #adi ---- ----1 used as a tug1 #aej ---- ----1 in clearing obstructions1 #aea ---- ----1 to clear away mines1 #aeb ,leclanch's ,voltaic battery1 #gg ,lewis's drifting torpedo1 #aag ,leyden jar1 the1 #bgi ,light1 ,siemens' electric1 #bda ---- ----1 conducting wires for1 #bdg ---- ----1 concentration of1 #bea ---- ----1 precautions in manipulating1 #beb ---- ----1 rotation of armatures in1 #bdf ---- ----1 wear and tear of1 #bdg ----1 the electric1 #bci ---- ----1 application of1 #bef ,lightning1 ,thornycroft's torpedo boat1 #afh ,lithofracteur1 #baf ,locomotive torpedoes1 #aca ,loss of the ,cairo1 #ahi ---- ---- ,commodore ,jones1 #ahi ,m4 ,machine1 description of a frictional electric1 #bgh ----1 ,siemens' low tension dynamo-electric1 #ge ,machines1 methods of coupling dynamo-electric1 #bed ,magnet1 the electro1 #bha ,magnetism1 #bgi ,magneto circuit closer1 ,mc,evoy's weight1 #ff ,magnets1 permanent1 #bhj ,main system1 ,mc,evoy's single1 #bhc ,manipulation of ,wheatstone's balance1 the1 #ih ,mari-,davy battery1 description of the1 #bge ,matchin1 ,russian torpedo boat attack at1 #aif ,material1 ,hooper's insulating1 #ci ,mathieson's cement safety plug1 #ba ---- circuit closer1 inertia1 #fa ---- ----1 improvements in1 #fc ---- ----1 spiral spring1 #fc ---- joint1 #de ,mc,evoy's drifting torpedo1 #aah ---- duplex spar torpedo1 #aed ---- improved ,singer's mine1 #bj ---- joint1 #df ---- mechanical mine1 #bb ---- ---- primer1 #ba ---- ---- ,turk's head1 #ec ---- mercury circuit-closer1 #fe ---- papier mach safety plug1 #bb ---- percussion fuzes1 #bd ---- platinum wire fuzes1 #cd ---- single main system1 #bhc ---- weight magneto circuit-closer1 #ff ,measurement of resistance by ,wheatstone's balance1 #ih ,measuring electrical resistances1 #ic ---- the intensity of a current1 #ie ,mechanical mines1 #aj1 #af ---- ----1 advantages of1 #ag ---- ----1 best kinds of1 #ag ---- ----1 extempore1 #ba ---- ----1 for coast defence1 #af ---- ----1 in the ,american war1 #af ---- ----1 ,mc,evoy's1 #bb ---- ---- improved ,singer's1 #bj ---- ----1 mooring1 #bf ---- ----1 ,russian electro1 #fh ---- ----1 ,singer's1 #ai ,mechanical primer1 ,abel's1 #bc ---- ----1 ,mc,evoy's1 #ba ---- tests1 #he ,medway1 experiments with countermines in the1 #bcf ,menotti cell1 description of the1 #gh ---- test batteries1 #gi ,menzing's towing torpedo1 #acj ,mercury circuit-closer1 ,mc,evoy's1 #fe ----1 fulminate of1 #bae ,metallic joint1 ,nicholl's1 #de ,method of carrying fish torpedoes1 ,thornycroft's1 #adj ---- ---- sinking and raising ,lay's torpedo1 #adi ---- ---- testing1 the ,austrian1 #aji ,methods of attack with ,harvey's torpedoes1 #aba ---- ---- coupling dynamo-electric machines1 #bed ---- ---- generating electricity1 #bfi ---- ---- protecting ships against torpedo attacks1 #ahj ---- ---- projecting ,whitehead's fish torpedo1 #ace ,mines1 submarine1 electrical1 #aj1 #bg ---- ----1 advantages of1 #bh ---- ----1 defects of1 #bi ---- ----1 mooring1 #ed ---- ----1 in the ,american war1 #bg ---- ----1 electro-contact1 circuit-closers for1 #fc ---- ----1 ,fulton's stationary1 #e ---- ----1 mechanical1 #aj1 #af ---- ----1 advantages of1 #ag ---- ----1 extempore1 #ba ---- ----1 ,mc,evoy's1 #bb ---- ----1 improved ,singer's1 #bj ---- ----1 mooring1 #bf ---- ----1 ,russian electro1 #fh ---- ----1 ,singer's1 #ai ---- ----1 rules to be observed in planting1 #gd ---- ----1 sweeping for1 #aab ,mixtures1 explosive1 #bjh ,mode of firing ,harvey's torpedoes1 #aba ---- ----1 in #ahbi1 #f ,monitor ,duba ,saife1 destruction of the ,turkish1 #aig ,mooring1 ,austrian method of1 #ef ---- electrical submarine mines1 #ed ----1 fore and aft1 #ef ----1 ladder1 #ee ----1 launch for placing1 #eh ,mooring mechanical mines1 #bf ----1 single rope1 #ef ,morse firing keys1 #ha ,multiple cables1 #dc ---- ----1 junction boxes for1 #eb ,n4 ,nicholl's metallic joint1 #de ,nitro-glycerine1 #bji ,nordenfelt torpedo gun1 the1 #beg ,norwegian torpedo launches1 ,thornycroft's1 #afc ,o4 ,observation1 firing by1 #fi ---- ----1 ,prussian system of1 #gc ,observing telescope1 shutter apparatus and1 #hd ,obstructions1 destruction of passive1 #aac ----1 ,lay's torpedo in clearing away1 #aea ,offensive torpedo operations1 ,russian and ,turkish1 #aie ---- ---- warfare still in its infancy1 #aae ---- torpedoes1 failure of1 #h1 #aa ---- ----1 general remarks on1 #aef ,ohm1 definition of the1 #bha ,ohm's law1 application of1 #bgf ,operations1 torpedo1 #ahg ---- ----1 during the ,american civil war1 #ahi ---- ---- ,austrian war1 #aib ---- ---- ,austro-,italian war1 #ahh ---- ---- ,crimean war1 #ahg ---- ---- ,franco-,german war1 #aib ---- ---- ,paraguayan war1 #aia ---- ---- ,russo-,turkish war1 #aib ---- ---- defensive1 ,russian1 #aic ---- ----1 ,turkish1 #aic ---- ---- offensive1 ,turkish and ,russian1 #aie ,ordinary type of torpedo boat1 the1 #agi ,ottoman fleet1 cause of failure of the1 #ad ,outrigger torpedoes1 spar or1 #aed ,p4 ,papier mach safety plug1 ,mc,evoy's1 #bb ,paraguayan war1 torpedo operations during the1 #aia ,passage through torpedo defences1 clearing a1 #aaa ,passive obstructions1 destruction of1 #aac ,patent electric lamp1 ,siemens'1 #bdh ---- torpedo boat protective1 ,fosberry's1 #ahb ,percussion fuzes1 #bc ---- ----1 ,mc,evoy's1 #bd ,permanent joint1 ,siemens'1 #dg ---- magnets1 #bhj ,physical state of the explosive substance1 the1 #bjd ,picric powder1 #bji ,planting submarine mines1 rules to be observed in1 #gd ,plates1 ,brown's arrangement of earth1 #ajj ----1 connections of switch1 #ajj ,platinum wire fuze for conductivity1 test of1 #aja ---- ----1 test of resistance of1 #aja ---- ---- fuzes1 #cc ---- ----1 ,english service1 #cc ---- ----1 ,mc,evoy's1 #cd ,plongeur1 ,french submarine boat1 #ahe ,plug1 ,mathieson's cement safety1 #ba ----1 ,mc,evoy's papier mach safety1 #bb ,pola1 torpedo experiments at1 #bca ,polarization1 definition of the term1 #bgc ,porter's torpedo ship ,alarm1 ,admiral1 #aei ,portsmouth1 torpedo experiments at1 #bbi1 #bcc ,potential1 definition of1 #bgj ----1 ,voltaic battery test for1 #ajd ,powder1 ,horsley's1 #baf ----1 picric1 #bji ,precautions in manipulating the electric light1 #beb ,primer1 ,abel's mechanical1 #bc ----1 ,mc,evoy's1 #ba ,projecting frames for torpedo ship defence1 #aaa ---- ,whitehead's fish torpedo1 methods of1 #ach ,propeller1 ,thornycroft's screw1 #agj ,properties of a ,voltaic cell1 definition and1 #bfi ,prussian system of firing by observation1 the1 #gc ,q4 ,quadrant electrometers1 ,thomson's1 #hf ,qualifications essential to submarine boats1 the1 #ahd ,r4 ,rain's detonating composition1 #bc ,reflecting galvanometer1 ,thomson's1 #hg ,reflector1 ,colt's1 #g ,remarks on offensive torpedoes1 general1 #aef ,resistance boxes1 #ig ---- of cables1 test of electrical1 #ajd ---- platinum wire fuze1 test of1 #aja ----1 ,voltaic battery test for internal1 #ajd ,resistances by ,wheatstone's balance1 measurement of1 #ih ----1 circuit1 #bgf ----1 measuring electrical1 #ic ,rheostat1 the1 #if ,rope mooring1 single1 #ef ,rotation of armatures in ,siemens' electric light apparatus1 #bdf ,roux and ,sarrau1 experiments by1 #bjg ,rules in connection with submarine mines1 #bi ---- to be observed in forming cable joints1 #ea ---- ---- planting mines1 #gd ,russian and ,turkish offensive torpedo operations1 #aid ---- defensive torpedo operations1 #aic ---- electro-mechanical mines1 #fh ---- torpedo boat attack at ,batoum1 #aae1 #bjb ---- ---- ,matchin1 #aif ---- ---- ,rustchuk1 #bjj ---- ---- ,soukoum ,kaleh1 #bja ---- ---- ,soulina1 #aih ---- ---- off the ,aluta1 #bjj ---- ----1 the final1 #bjc ---- ---- boats1 ,schibau's1 #agh ---- ---- launch1 ,yarrow's1 #agb ---- torpedoes1 #aic ,russo-,turkish war1 torpedo operations during the1 #aib ---- ----1 torpedoes during the1 #ad1 #aae ,rutschuk1 ,russian torpedo attack at1 #bjj ,s4 ,safety cock arrangement1 ,steward's1 #be ---- plug1 ,mathieson's cement1 #ba ---- ---- ,mc,evoy's papier mach1 #bb ,schibau's ,russian torpedo boats1 #agh ,science of torpedo warfare1 the1 #ae ,sea cell test for insulation1 #ajf ---- ---- tests1 #ajj ---- service cables1 #dc ,second class torpedo launches1 ,thornycroft's1 #afi ,self-acting circuit closer1 the ,austrian1 #fd ,sensitive fuzes1 #bc ,service cables1 land1 #dc ---- ----1 sea1 #dc ---- platinum wire fuze1 ,english1 #cc ,ship ,alarm1 ,admiral ,porter's torpedo1 #aei ---- defence1 #aj ----1 ,fulton's block1 #e ,ships against torpedo attacks1 methods of protecting1 #ahj ----1 employment of torpedo1 #aeh ,shunt1 definition of a1 #ie ---- for ,siemens' electric light1 self-acting1 #bde ,shutter apparatus1 firing keys and1 #hj ---- ----1 the1 #hb ---- used with a circuit breaker1 #hc ---- instrument and observing telescope1 #hd ,siemens' electric cables1 #dj ---- ---- light apparatus1 #bda ---- ----1 conducting wires for1 #bdg ---- ----1 description of1 #bda ---- ----1 power and light produced by1 #bdd ---- ----1 rotation of armatures in1 #bdf ---- ----1 self-acting shunt for1 #bde ---- ----1 wear and tear of1 #bdg ---- low tension dynamo machine1 #ge ---- patent electric lamp1 #bdh ---- permanent joints1 #dg ---- universal galvanometer1 #hi ---- ---- tables1 #bhg ,signal1 firing by preconcerted1 #ga ,signals employed in diving1 #bfc ,silvertown electric cables1 #da ,singer's mechanical mine1 #ai ---- ----1 ,mc,evoy's improved1 #bj ,single and double fluid batteries1 #bgb ---- cored armoured cables1 #dc ---- ---- unarmoured cables1 #dc ---- fluid cell1 action in a1 #bgc ---- main system1 ,mc,evoy's1 #bhc ---- rope moorings1 #ef ,size of torpedo charges1 #bah ,soukoum ,kaleh1 ,russian torpedo attack at1 #bja ,soulina1 ,russian torpedo attack at1 #aih ,spanish torpedo boats1 ,yarrow's1 #age ,spar or outrigger torpedoes1 #aed ---- torpedo1 ,mc,evoy's duplex1 #aed ---- torpedoes1 ,fulton's1 #e ,special cables1 #dc ,spherical shaped torpedo case1 the1 #cb ,spiral spring circuit closer1 ,mathieson's1 #fc ,stake torpedoes1 #ah ,state of the explosive substance1 the physical1 #bjd ,statham's high tension fuze1 #ce ,stationary mines1 ,fulton's1 #e ,steward's safety cock arrangement1 #be ,stokes ,bay1 experiments with countermines at1 #bcf ,submarine boat1 ,bushnell's1 #b1 #ahd ---- ----1 ,confederate1 #ahe ---- ----1 ,french1 #ahe ---- boats1 #ahc ---- ----1 qualifications essential to1 #ahd ---- mines #ac ---- ----1 during the ,crimean and ,american wars1 #bg ---- ----1 rules for using1 #bi ---- ----1 sweeping for1 #aab ---- ----1 electrical1 #bg ---- ----1 advantages of1 #bh ---- ----1 defects of1 #bi ---- ----1 mooring1 #ed ,submersion1 tests after1 #ajf ,success in torpedo warfare1 elements of1 #af ,suna1 destruction of the ,turkish vessel1 #aid ,swedish torpedo launch1 ,thornycroft's1 #afe ,sweeping for submarine mines1 #aab ,switch plates1 commutators or1 #if ---- ----1 connections of1 #ajj ,synopsis1 #bij ,system1 ,mc,evoy's single main1 #bhc ---- of electrical testing1 ,armstrong's1 #ajg ---- ---- firing by observation1 ,prussian1 #gc ---- ---- tests1 object of1 #hd ,t4 ,t junction box1 the1 #ec ,table1 the ,austrian testing1 #ajh ,tables1 ,siemens' universal galvanometer1 #bhg ----1 test1 #ii ,tactics with ,harvey's torpedoes1 #abg ,telegraph batteries1 #gi ,telescope1 shutter instrument and observing1 #hd ,tension dynamo machines1 ,siemens' low1 #ge ---- fuses1 testing high1 #ajb ,term torpedo1 definition of the1 #aae ,terms electro-positive and electro-negative1 the1 #bga ,test battery1 the ,menotti1 #gi ----1 discharge1 #ajc ---- for electrical cables1 insulation1 #ajb ---- of electrical resistance of cables1 #ajd ---- ---- insulated joints1 electrical1 #ajd ---- ---- platinum wire fuze for conductivity1 #aja ---- ---- resistance1 #aja ---- tables1 #ii ,testing1 ,armstrong's system of electrical1 #ajg ----1 ,austrian method of1 #aji ---- high tension fuzes1 #ajb ----1 instruments used in1 #he ---- table1 ,austrian1 #ajh ,tests after submersion1 #ajf ----1 electrical1 #he ---- for insulation1 sea cell1 #ajf ----1 mechanical1 #he ----1 object of a system1 #hd ----1 sea cell1 #ajj ,theoretical knowledge of torpedoes1 #h ,theory of detonation1 the1 #bjf ---- ---- electricity1 the1 #bfe ,thermo galvanometer1 the1 #hi ,thomson's quadrant electrometer1 #hf ---- reflecting galvanometer1 #hg ,thornycroft's boat engines1 efficiency of1 #aga ---- method of carrying fish torpedoes1 #adj ---- propeller1 #agj ---- torpedo launches1 #afc ---- ----1 ,austrian and ,french1 #afe ---- ----1 ,danish and ,swedish1 #afe ---- ----1 ,dutch and ,italian1 #afh ---- ----1 ,french1 #afi ---- ----1 ,norwegian1 #afc ---- ----1 second class1 #afi ,three coil galvanometer1 #hh ,torpedo attacks1 boat1 #ahj1 #aia ---- ----1 methods of protecting ships against1 #ahj ---- boat1 ,lay's1 #ada ---- ----1 capabilities of1 #adg ---- ----1 an improved form of1 #aec ---- ---- attack1 ,russian1 at ,batoum1 #aie1 #bjb ---- ---- ---- ---- ,matchin1 #aif ---- ---- ---- ---- ,rustchuk1 #bjj ---- ---- ---- ---- ,soukoum ,kaleh1 #bja ---- ---- ---- ---- ,soulina1 #aih ---- ---- ----1 off the ,aluta1 #bjj ---- ---- ----1 the final1 #bjc ---- ---- experiment at ,cherbourg1 #agj ---- ---- for flotation1 #aga ---- ---- ,lightning1 ,thornycroft's1 #afh ---- ---- protective1 ,fosberry's patent1 #ahb ---- boats1 #afb ---- ----1 ,herreshoff's1 #agh ---- ----1 ordinary type of1 #agi ---- ----1 ,schibau's ,russian1 #agh ---- ----1 ,yarrow's1 #agb ---- ----1 description of a1 #agb ---- ---- ,dutch1 #agb ---- ---- ,english1 #agc ---- ---- ,russian1 #agb ---- ---- ,spanish1 #age ---- case1 form and construction of1 #ca ---- ----1 conical shaped1 #cb ---- ----1 cylindrical shaped1 #cb ---- ----1 spherical shaped1 #cb ---- charges1 size of1 #bah ---- defences1 clearing a passage through1 #aaa ---- experiments at ,carlscrona1 #bbj1 #bbd1 #bcb ---- ---- ,chatham1 #bbj ---- ---- ,copenhagen1 #bbc ---- ---- ,kiel1 #bbb ---- ---- ,pola1 #bca ---- ---- ,portsmouth1 #bbi1 #bcc ---- ---- in ,austria1 #bbj ---- ---- ,england1 #bbb ---- ---- ,turkey1 #bcb ---- explosive agents1 #bag ,torpedo guns1 #beg ---- ----1 ,hotchkiss1 #bei ---- ----1 ,nordenfelt1 #beg ---- invention and adoption of the fish1 #aca ---- launches1 ,thornycroft's1 #afc ---- operations1 #ahg ---- ---- during the ,austro-,italian war1 #ahh ---- ---- ,crimean war1 #ahg ---- ---- ,franco-,german war1 #aib ---- ---- ,paraguayan war1 #aia ---- ---- ,russo-,turkish war1 #aib ---- ----1 ,russian defensive1 #aic ---- ----1 ,turkish defensive1 #aic ---- ---- and ,russian offensive1 #aie ---- ship ,alarm1 ,admiral ,porter's1 #aei ---- ---- ,destroyer1 ,ericsson's1 #afj ---- ---- ,uhlan1 the ,german1 #aeh ---- ships1 employment of1 #aeh ---- spar1 ,mc,evoy's duplex1 #aed ---- ---- or outrigger1 #aed ----1 the term1 #aae ---- warfare1 defensive1 #ac ---- ----1 elements of success1 #af ---- ----1 science of1 #ae ---- ---- still in its infancy1 offensive1 #aae ----1 ,whitehead's fish1 #acc ---- ----1 adjustments of1 #acf ---- ----1 capabilities of1 #acd ---- ----1 methods of projecting1 #ach ----1 ,woolwich fish1 the1 #adj ----1 ,american extempore drifting1 #aai ----1 barrel1 #ai ----1 ,brook's1 #ai ----1 ,bushnell's drifting1 #b ---- ----1 invention of1 #b ----1 drifting1 #aaf ----1 floating1 #aaf ----1 frame1 #ah ----1 ,fulton's drifting1 #e ---- ---- harpoon1 #e ---- ---- spar1 #e ----1 general remarks on offensive1 #aef ---- in war1 the employment of fish1 #acc ----1 ,lewis's drifting1 #aag ----1 locomotive1 #aca ----1 ,mc,evoy's drifting1 #aah ----1 moral effect of1 #i ----1 offensive1 #aa ---- ----1 failure of #h ----1 stake #ah ----1 towing #aai ---- ----1 ,french1 #aca ---- ----1 ,harvey's1 #aai ---- ----1 methods of attack with1 #abg ---- ----1 the value of1 #abi ---- ----1 ,mensing's1 #acj ----1 turtle #ai ,turkey1 torpedo experiments in1 #bcb ,turkish defensive torpedo operations1 #aic ---- monitor ,duba ,saife1 destruction of the1 #aig ---- offensive torpedo operations1 #aie ---- ship ,suna1 loss of the1 #aid ---- torpedoes1 #aic ---- war1 torpedoes during the ,russo-1 #aae ,turk's head1 ,mc,evoy's mechanical1 #ec ,turtle torpedoes1 #ai ,u4 ,uhlan1 the ,german torpedo vessel1 #aeh ,unarmoured cables1 single cored1 #dc ,universal galvanometer1 ,siemens'1 #hi ---- ----1 tables1 #bhg ,use of circuit closers1 the1 #fj ,v4 ,vessel ,destroyer1 ,ericsson's torpedo1 #afj ---- in the world1 the fastest1 #agg ---- ,uhlan1 the ,german torpedo1 #aeh ,voltaic batteries1 #gi ---- battery1 ,leclanch's1 #gg ---- ----1 ,von ,ebner's1 #gf ---- ----1 test for electro-motive force1 #aje ---- ---- internal resistance1 #ajd ---- ---- potential1 #ajd ---- cell1 definition and properties of a1 #bfi ---- current1 the1 #gj ,von ,ebner's high tension fuze1 #cf ---- ---- ,voltaic battery1 #f ,w4 ,war1 employment of fish torpedoes in1 #acc ----1 torpedo operations during the ,american civil1 #ahi ---- ---- ,austrian1 #aib ---- ---- ,austro-,italian1 #ahh ---- ---- ,crimean1 #ahg ---- ---- ,franco-,german1 #aib ---- ---- ,paraguayan1 #aia ---- ---- ,russo-,turkish1 #aib ----1 torpedoes during the ,american civil1 #aae ---- ----1 ,russo-,turkish1 #aae ,warfare1 defensive torpedo1 #ac ----1 elements of success in torpedo1 #af ----1 science of torpedo1 #ae ---- still in its infancy1 offensive torpedo1 #aae ,wars1 submarine mines in the ,crimean and ,american1 #bg ,wear and tear of ,siemens' electric light apparatus1 #bdg ,welden railway saved by torpedoes1 the1 #aij ,wheatstone's balance1 #ig ---- ----1 manipulation of1 #ii ---- ----1 measurement of resistances by1 #ih ,whitehead's fish torpedo1 #acc ---- ----1 adjustments of1 #acf ---- ----1 capabilities of1 #acd ---- ----1 methods of projecting1 #ach ---- ----1 mode of ignition of1 #ace ,wire fuze for conductivity1 test of platinum1 #aja ---- ----1 test of resistance of platinum1 #aja ,wire fuzes1 platinum1 #cc ---- ----1 ,english service1 #cc ---- ----1 ,mc,evoy's1 #cd ,wires in ,mc,evoy's spar torpedo1 arrangement of1 #aee ,woolwich fish torpedo1 the1 #adj ,y4 ,yarrow's torpedo boats1 #agb ---- ----1 ,english1 #agc ---- ----1 ,spanish1 #age ---- ---- launch1 description of a1 #agb ---- ---- launches1 ,dutch1 #agb ---- ----1 ,russian1 #agb ,,griffin ,,and ,,co41 ,,publishers ,,by ,,appointment ,,to ,h4,r4,h4 ,,the ,,duke ,,of ,,edinburgh1 #b1 ,,the ,,hard1 ,,portsmouth4 ,,publications ,,of ,j4 ,,griffin ,,co41 ,naval ,publishers1 7,by ,appointment1 to ,h4,r4,h4 ,the ,duke of ,edinburgh47 #b1 ,,the ,,hard1 ,,portsmouth4 ,,london ,,agents3--,simpkin1 ,marshall1 and ,co41 ,london4 ,,the ,,duel3 ,a ,,naval ,,war ,,game1 ,invented and arranged by ,,capt4 ,,philip ,h4 ,,colomb1 ,r4,n41 with ,explanations and ,rules of the ,game1 and the necessary ,scales1 and large ,drawing ,block4 ,price #ajs4 #f;d4 ,captain ,colomb's ,war ,game will prove very useful to all ,executive ,officers4 ,it will become the ,naval ,chess4 ,i think it will prove of much advantage to the ,service4 ,it will open the eyes of many men who have hitherto thought and talked of the subject perhaps intelligently but not accurately4 ,,torpedoes ,,and ,,torpedo ,,warfare3 ,offensive and ,defensive4 ,being a ,complete ,history of ,torpedoes and their application to ,modern ,warfare4 ,by ,c4 ,,sleeman1 ,,esq41 late ,lieutenant ,r4,n41 and late ,commander ,imperial ,ottoman ,navy4 #a vol41 ,royal #hvo41 with ,illustrations and ,plates4 ,price #bds4 ,,vocabulary ,,of ,,sea ,,words4 ,in ,,english1 ,,french1 ,,german1 ,,spanish1 and ,,italian4 ,by ,commander ,,the ,,hon4 ,a4 ,c4 ,,littleton1 ,r4,n4 ,for the use of ,officers of the ,royal and ,mercantile ,navies1 ,yachtsmen1 ,travellers1 c4 ,strongly bound and interleaved throughout4 ,price #cs4 #f;d4 ,in addition to the ,english terms used in connection with the ,sea1 we have the same in ,french1 ,german1 ,spanish and ,italian4444 ,not merely to the seafaring man1 but also to the ordinary traveller1 this book recommends itself4--,u4,s4 ,gazette4 ,it is handy in size and complete in all respects1 provision having been made by blank leaves between each page for any additions that may have to be made4--,broad ,arrow4 ,,problems ,,in ,,naval ,,tactics4 ,by ,,vice-,,admiral ,,randolph1 ,c4,b4 ,with four ,full-,page ,diagrams4 ,demy #hvo4 #bs4 ,griffin ,co41 ,publishers1 #b1 ,the ,hard1 ,portsmouth4 ,,captain ,,colomb',s ,,naval ,,tactics ,in ,preparation4 ,,queen',s ,,regulations ,,and ,,admiralty ,,instructions--,new ,edition1 #ahgi4 #bs4#f;d4 ,,manual ,,of ,,gunnery1 ,corrected to #ahhj4 ,,the ,,ships ,,of ,,the ,,royal ,,navy #crd ,edition4 ,portraits of #bd ,ships1 beautifully ,lithographed in ,colors from ,original ,drawings4 ,demy #dto4 blue cloth1 extra gilt1 #cjs42 ,best ,morocco1 #c #cs42 ,russia1 #c #acs4 #f;d4 ',among illustrated works1 none has appeared of greater interest than this upon the ,royal ,navy4'--,times4 ',as an illustrated gift-book1 independent of its historic interest1 ,the ,royal ,navy1 from the truthfulness of its illustrations1 cannot but recommend itself1 not only to the ,royal ,service1 but also to the public4'--,united ,service ,gazette4 ',this beautiful work does credit to all concerned in its production4'--,pall ,mall ,gazette4 ,,the ,,war ,,ships ,,of ,,europe ,crown #hvo4 ,illustrated4 #ajs4 #f;d4 ,by ,chief-,engineer ,,king1 ,u4,s4,a4 ,descriptions of the ,construction1 ,armour and ,fighting ,power of the ,ironclads of ,england and other ,european ,powers of the present day4 ,revised and ,corrected throughout1 and with additional ,notes by an ,english ,naval ,architect4 ,a valuable and interesting contribution to maritime literature 444 interesting to the public 444 and instructive to the ,naval ,executive generally4--,united ,service ,gazette4 ,the book is invaluable as a brief but accurate description of the fighting powers of the ,ironclads of ,england and other ,european powers of the present day4--,broad ,arrow4 ,the whole volume possesses a deep interest4 ,its details are trustworthy4--,john ,bull4 ,,the ,,armies ,,of ,,europe ,,and ,,asia ,demy #hvo4 ,illustrated4 #ads4 ,by ,major-,general ,,upton1 ,u4,s4,a4 ,embracing ,official ,reports on the ,armies of ,japan1 ,china1 ,india1 ,persia1 ,italy1 ,russia1 ,austria1 ,germany1 ,france1 and ,england4 ,accompanied by ,letters descriptive of a ,journey from ,japan to the ,caucasus4 ,his sketch of travel1 though most unpretentious in manner1 is highly interesting as a preliminary introduction to the very important results of this military tour4 ,the value of this work1 particularly as a book of reference1 may be estimated from the fact that it contains the results of a lengthened and searching inquiry into matters connected with the great armies of the world1 which was conducted by officers of proved ability and enjoying exceptional advantages4444 ,it abounds in useful information1 and may be studied with no little advantage by those who wish to improve their knowledge of the art of modern war4--,united ,service ,gazette4 ,griffin ,co41 ,publishers1 #b1 ,the ,hard1 ,portsmouth4 ,,the ,,sailor',s ,,pocket ,,book #crd ,edition4 #gs4 #f;d4 ,by ,captain ,f4 ,g4 ,d4 ,,bedford1 ,r4,n4 ,a ,collection of ,practical ,rules1 ,notes1 and ,tables1 for the use of the ,royal ,navy1 the ,mercantile ,marine1 and ,yacht ,squadrons4 ,with ,colored ,signal ,flags1 ,charts1 and ,illustrations4 ,bound in leather1 #ejj pages1 and carefully compiled ,index4 ,a ,nautical ,cyclopdia4--,liverpool ,albion4 ,the most perfect and complete of any publication of the kind4--,u4,s4 ,gazette4 ,a valuable addition to a yachtsman's library4--,land and ,water4 ,valuable and excellently arranged little work4--,pall ,mall ,gazette4 ,a volume quite indispensable4--,the ,graphic4 ,an admirable and much wanted little book4--,edinburgh ,review4 ,,capt4 ,,sir ,,george ,s4 ,,nares' ,,seamanship #eth ,edition4 ,demy #hvo4 #bas4 #djj beautifully engraved ,woodcuts1 and ,plates of ,flags1 accurately ,colored4 ',it is the best work on ,seamanship we have4'--,standard4 ',is a book for the instruction of young officers1 and of reference for older ones it cannot be excelled1 many most valuable additions are made in this edition4 ,the book should be the officers' vade mecum4'--,united ,service ,gazette4 ',every necessary particular is given so fully and completely as to leave nothing to be desired4'--,shipping ,gazette4 ,,captain ,,alston',s ,,seamanship #bnd ,edition4 ,crown #hvo4 ,cloth1 #abs4 #f;d4 ,contains #bjj ,illustrations of ,rigging1 ,sails1 ,masts1 c42 with ,instructions for ,officers of the ,merchant ,service1 by ,w4 ,h4 ,,rosser2 forming a complete ,manual of ,practical ,seamanship4 ,the illustrations1 of which there are #bjj1 are well executed1 and the reviser has brought down to the present day all changes in the rig and build of ships of war4 ,the frontispiece gives sectional views of the screw steamship ,russia of the ,cunard line1 and ,h4,m4,s4 ,monarch4--,shipping ,gazette4 ,it has been revised and enlarged by ,commander ,r4 ,h4 ,harris1 ,r4,n41 and includes a treatise on nautical surveying by ,staff-,commander ,may1 and also some useful instructions for officers of the merchant service4 ,the book seems well adapted for junior officers of the navy1 and the sound advice and high moral tone of its introduction give it an additional recommendation4--,liverpool ,mercury4 ,,the ,,rigger',s ,,guide4 #ajth ,thousand4 ,new ,edition4 ,revised and enlarged4 ,cloth1 #cs4 ,by ,,charles ,,bushell4 ,fully ,illustrated4 ,being the best and only complete book of the ,rigging of ,ships4 ,this is a valuable little book1 adapted to suit every class of ship1 whether steam or sailing vessel1 and should form part of the kit of every youngster adopting the profession of the sea4 ,many oldsters will also find it valuable1 from the general information it contains4 ,the present is the sixth edition1 which has been carefully revised and corrected4--,u4 ,s4 ,gazette4 ,griffin ,co41 ,publishers1 #b1 ,the ,hard1 ,portsmouth4 ,,the ,,navy ,,of ,,to-,,day2 ,its ,moral and ,intellectual ,condition4 ,crown #hvo4 ,sewed1 #bs2 ,cloth1 #bs4 #f;d4 ,in the ,navy of ,to-,day1 we have a number of thoughtfully written essays which deserve to obtain the widest publicity4--,broad ,arrow4 ,a little work which all should peruse who have the interests of the ,navy at heart4--,christian ,world4 ,we can with confidence recommend the ,navy of ,to-,day as a book well worthy of attentive reading4 ,we recommend chap4 v4 more particularly to the earnest consideration of ,naval ,officers4--,u4,s4 ,gazette4 ,,sea ,,terms ,,and ,,phrases4 ,,english ,,and ,,french4 ,by ,lieut4 ,e4 ,,pornain1 ,french ,navy4 ,for the use of ,officers of ,royal and ,mercantile ,navies1 ,engineers1 ,shipbuilders1 ,ship ,owners1 ,merchants1 ,ship ,brokers4 ,crown #hvo4 #ds4 ,a copy should be possessed by everyone whose profession1 occupation1 or interests bring them into relationship with a seafaring life4--,british ,mercantile ,review4 ,a ,nautical ,phrase ,book in two languages 444 a completeness which leaves nothing to be desired4--,hampshire ,telegraph4 ,,the ,,active ,,list ,of ,,admirals and ,,captains4 ,by ,capt4 ,,william ,,arthur1 ,r4,n4 ,demy #hvo4 ,with particulars exhibiting the progress1 c41 of ,officers1 of the ,royal ,navy1 from their entry into the ,service to ,jan4 #ast1 #ahgi4 ,,the ,,active ,,list ,of all ,,commanders and ,,lieutenants3 ,corrected to ,july #ast1 #ahgh4 ,by ,lieut4 ,m4 ,r4 ,,hayes1 ,r4,n4 ,demy #hvo4 #cs4 #f;d4 ,showing ,dates of ,entry1 and ,commissions1 ,,ages1 ,,and ,,amount ,,of ,,sea ,,time1 ,causes of ,special ,promotions1 ,special ,acquirements1 ,comparative ,progress with other ,officers1 ,list of all ,officers now on the ,active ,list who were promoted to the rank of ,commander from ,flag-,lieut4 or ,her ,majesty's ,yacht1 the ,age and ,sea ,time of ,commanders1 and other interesting particulars4 ,,harvey',s ,,sea ,,torpedoes4 ,with #ab ,plates1 #bs4 #f;d4 ,griffin ,co41 ,publishers1 #b1 ,the ,hard1 ,portsmouth4 ,,on ,,the ,,relative ,,merits ,,of ,,simple ,,and ,,compound ,,engines4 ,demy #hvo4 #ds4 #f;d4 ,by ,,niel ,,macdougall1 ,esq4 ,with numerous ,diagrams and ,illustrations4 ,the ,book will prove instructive and interesting to all engaged in ,marine ,engineering pursuits1 and the ,engineer ,officers of the ,royal ,navy in particular are heartily recommended it4--,broad ,arrow4 ,mr4 ,macdougall has treated this much-debated and highly-important question of the ,relative ,merits of ,simple and ,compound ,engines in a vigorous1 practical1 and highly creditable manner4--,naval ,science4 ,,journal ,,book ,,and ,,diary1 ,for the use of the ,officers of the ,royal ,navy4 ,after the ,style and ,size of ,letts's ,diary4 ,containing ,two ,days on a page1 with ruled paper1 and a ,printed ,journal ,form to each ,day1 for recording ,course and ,distance1 ,wind and ,weather1 ,barometer and ,thermometer1 ,latitude and ,longitude1 c4 ,containing also a variety of useful information--,regulations and ,course of ,study for the ,royal ,naval ,college1 ,greenwich2 ,course of ,instruction1 ,examination1 and ,regulations for passing through ,h4,m4 ,gunnery ,ships2 ,foreign ,monies and their ,english ,equivalents2 and a ,table showing the probable state of the ,,active ,,list ,,of ,,flag ,,officers ,,for ,,the ,,next ,,ten ,,years2 also ,notable ,events--,navy and ,army2 ,directions for making a ,will2 ,area of the ,principal ,states of the ,world2 ,passports1 c41 c4 ,prices1 strongly bound3-- ,one year1 #ds4 #f;d42 #b years1 #fs4 #f;d42 #c years1 #hs4 #f;d42 ,one year 7interleaved7 #es4 #f;d42 #b years 7interleaved7 #hs4 #f;d4 ,we would direct the attention of ,naval officers to a very complete ,naval ,diary1 which has just been compiled and published4 ,it has only to be shown to be appreciated4--,u4,s4 ,gazette4 ,,our ,,peril ,,afloat2 ,,or1 ,,collisions ,,and ,,how ,,to ,,avoid ,,them4 ,with ,illustrations4 #as4 ,by ,captain ,p4 ,h4 ,,colomb1 ,r4,n4 7,gold ,medalist1 ,royal ,u4,s4 ,institution47 ,,contents3 ,part ,i4 ,the ,rule of the ,road at ,sea3 its history and present condition2 ,part ,,ii4 ,the ,theory and ,practice of avoiding ,collision at ,sea2 and the ,regulations issued by ,order in ,council4 ,griffin ,co41 ,publishers1 #b1 ,the ,hard1 ,portsmouth4 ,,nautical ,,surveying4 ,by ,commander ,,may1 ,r4,n41 ,f4,r4,g4,s4 ,reprinted from ,alston's ,seamanship4 ,with ,charts4 #bs4 #f;d4 ,the treatise is simple and clear in arrangement1 and written with the especial object of instructing the officers of the ,naval ,service in general1 and only deals with the use of such instruments as are found on board of every man-of-war4 ,we have never met with any treatise on nautical surveying by any means so well calculated to answer the purpose for which it was written4--,naval ,science4 ,,the ,,manual ,,of ,,the ,,hydrometer4 #bnd ,edition4 ,illustrated4 ,cloth4 #cs4 #f;d4 ,by ,,lionel ,,swift1 ,r4,n4 '444 ,has been treated in the clear and simple manner which has been already manifested by ,mr4 ,swift1 in his accurate description of the history and philosophy of the ,hydrometer4'--,army and ,navy ,gazette4 ',will be found of considerable interest to ,engineers and all those who are interested in the safe and economical working of ,steam ,engines4'--,shipping and ,mercantile ,gazette4 ,by ,authority of the ,lords of the ,admiralty4 ,,questions ,,answers ,,on ,,the ,,ammunition ,,instruction4 ,for ,officers passing through ,h4,m4 ,gunnery ,establishments4 ,paper #as42 ,cloth1 #as4 #f;d4 ,by ,j4 ,,kite1 ,instructing ,gunner1 ,h4,m4,s4 ,excellent4 ,this book is a valuable multum in parvo4 ,all the multifarious details connected with ,ammunition ,instruction1 are dealt with ably and concisely4--,portsmouth ,times4 ,,traverse ,,tables ,cloth1 #es4 #f;d4 ,with simple and brief method of ,correcting ,compass ,courses4 ,by ,commander ,r4 ,e4 ,,edwin1 ,r4,n4 ,lieutenant ,edwin has been at great pains and trouble1 and he will probably save many hundreds of persons from calculations which are frequently wearisome to the flesh4--,broad ,arrow4 ,,definitions ,,in ,,navigation ,,and ,,nautical ,,astronomy4 7,,from ,,various ,,authorities47 ,new ,edition4 ,with ,diagrams4 ,demy #hvo4 ,cloth1 #bs4 #f;d4 ,for the use of the ,naval ,cadets1 ,h4,m4,s4 ,britannia4 ,griffin ,co41 ,publishers1 #b1 ,the ,hard1 ,portsmouth4 ,,land ,,of ,,the ,,white ,,bear4 ,the ,cruise of the ,pandora1 to the ,arctic ,seas in #ahge4 ,by ,,lieut4 ,f4 ,g4 ,,innes-,,lillingston1 ,r4,n4 ,with beautiful full-page ,illustrations4 ,cloth ,gilt1 #es4 ,the volume is prettily got up1 and the views of ,arctic scenery are about the best we have seen in any recent work of the kind4--,athenum4 ,thanks to ,english pluck and perseverance1 combined1 in so many instances1 with the ability to write a book1 we have become as familiar with ,arctic-life scenes and adventures as they can be made so by description4 ,in the present well-got-up little volume1 we have an account of the first voyage of the ,pandora4444 ,we can heartily recommend ,lieut4 ,innis-,lillingston's narrative--his first attempt1 as he tells us1 at book-writing--as giving a graphic account1 in a very unpretentious style1 of his most interesting1 but perilous cruise4444 ,as a gilt book1 we can also recommend the ,land of the ,white ,bear1 for it is exceedingly well illustrated1 and both in letter-press and binding is in the ,messrs4 ,griffin's usually good style4--,u4,s4 ,gazette4 ,,the ,,last ,,four ,,days ,,of ,,the ,,eurydice4 ,by ,captain ,e4 ,h4 ,,verney1 ,r4,n4 ,with ,portrait of the ,eurydice4 ,cloth4 #bs4 #f;d4 ,capt4 ,verney has done his work remarkably well1 and with the best possible taste4 ,he does not moralize or try to improve the occasion1 but1 writing with a restrained pathos and a graphic touch1 he lets the stern simple facts speak for themselves4--,athenum4 ,the circumstances attending the foundering are given as far as they are known1 and also details of the ship and its armament1 with lists1 of the officers and crew who perished4 ,the book forms an interesting souvenir of the melancholy event4--,court ,journal4 ,,memoir ,,of ,,commodore ,j4 ,g4 ,,goodenough1 ,c4,b4 ,,by ,,clements ,r4 ,,markham1 ,c4,b41 ,f4,r4,s4 ,,with ,,portrait4 ,crown #hvo41 ,cloth4 #bs4 #f;d4 ,a complete account of a singularly beautiful career4--,broad ,arrow4 ,a touching memento of the gallant sailor4--,court ,journal4 ,,the ,,history ,,of ,h4,m4,s4 ,,victory4 #as4 cloth2 paper1 #f;d4 #beth ,thousand4 ,by ,commander ,w4 ,j4 ,l4 ,,wharton1 ,r4,n4 ,a most interesting ,memoir of the famous ship in which ,nelson won his crowning triumph and death4 ,griffin ,co41 ,publishers1 #b1 ,the ,hard1 ,portsmouth4 ,,modern ,,naval ,,hygiene4 ,cloth4 #bs4 ,translated from the ,french by ,,john ,,buckley1 ,esq41 ,staff-,surgeon1 ,r4,n4 ,,the ,,west ,,coast ,,of ,,africa1 ,,as ,,seen ,,from ,,the ,,deck ,,of ,a ,,man-,,of-,,war4 ,illustrated4 ,demy #hvo41 ,cloth4 #gs4 #f;d4 ,by ,captain ,h4 ,,dyer1 ,r4 ,n4 ,we think the friends of the late ,commander ,dyer have done well in publishing this little volume as a memorial to one whom they loved1 both as a genial companion and an officer4 ,the character of the book1 which since it bears the stamp-mark of merit1 needs no eulogy to make it a successful publication4 ,that large class of readers which takes pleasure in perusing books of travel cannot do better than read this well-printed volume4--,broad ,arrow4 ,,light ,,from ,h4,m4,s4 ,,torch4 ,demy #hvo41 ,cloth4 #bs4 #f;d4 ,by ,capt4 ,h4 ,,dyer1 ,r4,n4 ,with ,portrait4 ,,memoir ,,of ,,admiral ,,sir ,h4 ,d4 ,,chads1 ,k4,c4,b4 ,with ,portrait4 #bs4 ,,search ,,for ,,sir ,,john ,,franklin4 ,price #as4 ,from the ,journal of ,capt4 ,sir ,,allen ,,young4 ,illustrated4 ,by ,authority4 ,,course ,,of ,,instruction ,,in ,,gunnery ,,ships ,,for ,,officers ,,and ,,men4 ,demy #hvo4 #as4 ,,royal ,,naval ,,artillery ,,volunteers ,,gunnery ,,drill ,,book4 ,copiously illustrated with ,diagrams4 #as4 #f;d4 ,griffin ,co41 ,publishers1 #b1 ,the ,hard1 ,portsmouth ,,engineer ,,officer',s ,,watch1 ,,station1 ,,quarter1 ,,fire ,,bills4 ,by ,,william ,j4 ,j4 ,,spry1 ,r4,n4 #cs4 #f;d4 ,a complete vade mecum for ,engineer ,officers in ,her ,majesty's ,navy4 ,,table ,,for ,,correction ,,of ,,longitude ,,where ,,error ,,arises ,,from ,,incorrect ,,latitude4 #bnd ,edition4 #as4 ,by ,,gilbert ,t4 ,,key1 ,commander1 ,r4,n4 ,,the ,,pilot',s ,,handbook ,,for ,,the ,,english ,,channel4 #gth ,edition4 #gs4 ,illustrated with #ag plates4 ,by ,staff-,commander ,,king1 ,r4,n4 ,manual for the use of the ,boatmen preparing for ,examination in ,,coast ,,guard ,,service4 ,published by ,authority4 ,with ,chart4 ,demy #hvo4 #as4 #f;d4 ,,mess ,,wine ,,books ,with ,cash ,book and ,ledger1 complete in ,one ,volume4 ,for #bd ,members1 #aes42 ,for #ab ,members1 #abs4 #f;d4 ,rough ,daily ,wine ,book1 #hs4 #f;d4 ,,progress ,,book ,,for ,,the ,,use ,,of ,,naval ,,instructors4 #abs4 #f;d4 ,,watch1 ,,quarter1 ,,station1 ,,and ,,fire ,,bill4 ,admiralty ,form1 ,no4 #b1 #bs4 #f;d4 ,no4 #c1 #bs4 ,,the ,,admiralty ,,manual ,,of ,,scientific ,,enquiry4 #dth ,edition4 #cs4 #f;d4 ,griffin ,co41 ,publishers1 #b1 ,the ,hard1 ,portsmouth4 ,,journal ,,books4 ,one ,year1 #fs4 #f;d2 ,two ,years1 #hs4 #f;d42 ,three ,years1 #ajs4 #f;d4 ,four ,years1 #abs4 #f;d4 ,,log ,,books 7,,ruled74 ,two quires1 #hs4 ,three quires1 #ajs4 #f;d4 ,,certificate ,,cases4 ,half roan1 #bs4 #f;d4 ,,text ,,book ,,on ,,the ,,construction ,,and ,,manufacture ,,of ,,ordnance4 ,printed by ,order of the ,secretary of ,state for ,war4 ,second ,edition4 ,colored ,illustrations4 ,cloth ,boards4 #ahgi4 ,abridged ,edition4 #is4 ,handbook of the ,manufacture and ,proof of ,gunpowder4 ,by ,capt4 ,f4 ,m4 ,,smith1 ,royal ,artillery4 #hvo41 cloth boards4 ,with ,plates and ,diagrams4 #es4 ,text ,book on the ,,theory ,,of ,,the ,,motion ,,of ,,projectiles1 the ,history1 ,manufacture1 and ,explosive ,force of ,gunpowder2 and the ,history of ,small ,arms4 ,published by ,authority4 ,with ,diagrams4 ,cloth ,boards4 #bs42 interleaved1 #bs4 #f;d4 ,,rifle ,,and ,,field ,,exercises ,,and ,,musketry ,,instruction ,,for ,,her ,,majesty',s ,,fleet1 #ahgh4 #as4 #f;d4 ,,manual ,,and ,,firing ,,exercises ,,for ,,the ,,martini-,,henry ,,rifle4 ,for the use of the ,navy4 ,by ,authority4 ,threepence4 ,,field ,,exercise4 #ahgg4 #as4 ,griffin ,co41 ,publishers1 #b1 ,the ,hard1 ,portsmouth4 ,,rifle ,,exercise ,,and ,,musketry ,,instruction--#ahgi4 #as4 ,,chronometer ,,journal--,with ,diagrams4 #abs4 #f;d4 ,,nosological ,,journal--#is4 ,,clothes ,,and ,,slop ,,list--#es4 and #hs4 #f;d4 ,,clothes ,,list--,new ,pattern4 #ds4 #f;d4 and #gs4 #f;d4 ,,the ,,sick ,,list--#ds4 #f;d4 and #gs4 #f;d4 ,,with ,,alphabet--#es4 ,,and #hs4 ,,night ,,order ,,book--#es4 #f;d4 ,,washing ,,book ,,for ,,naval ,,officers--#f;d4 ,,annual ,,of ,,the ,,royal ,,school ,,of ,,naval ,,architecture ,,marine ,,engineering4 ,parts #a to #d--bs4 #f;d4 each4 ,parts #a and #d contain particulars of ,english and ,foreign ,ironclads4 ,,treatise ,,on ,,ammunition--#fs4 ,,manual ,,of ,,field ,,fortification--#cs4 ,,notes ,,on ,,ammunition4 ,published by ,authority4 ,corrected to ,july1 #ahgg4 ,with ,diagrams1 cloth boards1 #bs4 #f;d4 ,,battalion ,,words ,,of ,,command--#c;d4 ,,the ,,sappers' ,,manual--,part #a4--bs4 ,griffin ,co41 ,publishers1 #b1 ,the ,hard1 ,portsmouth4 ,,the ,,arctic ,,navy ,,list3 ,,or ,a ,century of ,arctic and ,antarctic ,officers4 #aggc-ahgc4 ,by ,,clements ,r4 ,,markham1 ,c4,b41 ,f4,r4,s4 ,with ,officers of #ahge ,expedition1 and ,circumpolar ,chart4--#cs4#f;d4 ,,sailor',s ,,word ,,book ,a ,nautical and ,military ,vocabulary4 ,by ,admiral ,,smyth4 ,thick #hvo41 cloth4 ,published at #bas4 ,reduced to #abs4 #f;d4 ,,the ,,justices' ,,pocket ,,manual #crd ,edition4 ,by ,,thomas ,,cousins1 ,esq4 ,bound in ,leather4 #bs4 #f;d4 ,the great merit of ,mr4 ,cousins' ,manual is1 that it gives ,magistrates explicit information on most of the details of their office in a surprisingly brief space4 ,the magistrates' vade mecum4--,law ,times4 ,,short ,,whist ,,register ,,and ,,summary ,with the ,laws of the ,game1 c4 ,by ,t4 ,c4 ,cloth1 #cs4 #f;d4 ,,ships' ,,crests4 ,stamped in ,colors4 #dj ,crests on each sheet1 #e different sheets1 ,one ,shilling each ,,also1 ,illuminated ,ships' ,crests1 #i on each sheet1 #aj different ,sheets4 ,one ,shilling each4 ,a complete set1 consisting of #ij ,crests1 ,illuminated in ,gold and ,colors1 and #bjj in ,colors1 costs #aes4 ,griffin ,co41 ,publishers1 #b1 ,the ,hard1 ,portsmouth4 ,,pamphlets4 ,remarks on ,naval ,warfare and on the ,navy4 ,by a ,naval ,officer4 ,one ,shilling4 ,the ,admiralty4 ,by a ,flag ,officer4 ,second ,edition4 ,one ,shilling4 ,a ,naval ,reserve of the ,future4 ,by ,commander ,arthur ,h4 ,gilmore1 ,r4,n4 ,one ,shilling4 ,imperial ,defence4 ,by ,captain ,p4 ,c4 ,colomb4 ,two ,shillings4 ,the ,loss of the ,captain4 ,by an ,officer of ,h4,m4,s4 ,minotaur4 ,sixpence4 ,the ,church in the ,navy1 its ,communicants and ,bible ,classes4--#f;d4 ,on the ,holy ,communion in the ,navy4 ,by a ,commander1 ,r4,n4 ,demy #afmo4 ,sixpence4 ,some ,remarks on ,naval ,education4 ,by ,captain ,a4 ,gardner1 ,r4,n4 ,sixpence4 ,life-,saving at ,sea1 ,,by ,,cork ,,life-,,belts ,,or ,,mattresses1 c41 ,by ,vice-,admiral ,a4 ,p4 ,ryder4 ,second ,edition4 ,demy #hvo4 ,one ,shilling4 ,,seamen',s ,,prayers4 ,for the use of the ,royal ,navy2 and also ,merchant ,service4 #hdth ,,thousand2 on ,card4 #bs4 per #ajj4 ,per post1 #bs4 #f;d4 ,griffin ,co41 ,publishers1 #b1 ,the ,hard1 ,portsmouth4 ,,naval ,,professional ,,books4 ,,sold ,,by ,,messrs4 ,,griffin ,,co4 ,,on ,,modern ,,artillery2 ,its ,principles and ,practice4 ,by ,lieut-,col4 ,c4 ,h4 ,owen4 #aes4 ,,the ,,physical ,,geography ,,of ,,the ,,sea ,,and ,,its ,,meteorology4 #aeth ,edition4 ,by ,m4 ,f4 ,maury1 ,,ll4,d4 #es4 ,,on ,,the ,,laws ,,of ,,storms4 ,considered practically4 ,by ,w4 ,h4 ,rosser4 #es4 ,,the ,,sailor',s ,,horn-,,book ,,for ,,the ,,law ,,of ,,storms3 ,being a ,practical ,exposition of the ,theory of the ,law of ,storms4 ,by ,h4 ,piddington4 #eth ,edition4 #ajs4 #f;d4 ,,on ,,the ,,steam ,,engine4 ,by ,w4 ,ewers4 #cs4 ,,lights ,,and ,,tides ,,of ,,the ,,world4 #dth ,edition4 #as4 ,,naval ,,architecture4 ,by ,w4 ,h4 ,white4 #bds4 ,,naval ,,architecture4 ,by ,samuel ,j4 ,p4 ,thearle4 ,with ,volume of ,plates4 7,practical7 #gs4 #f;d4 7,theoretical7 #ajs4 #f;d4 #b ,vols4 ,,weather ,,charts ,,and ,,storm ,,warnings4 ,by ,robert ,h4 ,scott1 ,m4,a41 ,f4,r4,s4 #cs4 #f;d4 ,a ,,treatise ,,on ,,the ,,criminal ,,law ,,of ,,the ,,navy4 ,by ,theodore ,thring4 #hs4 #f;d4 ,,handbook ,,of ,,the ,,laws ,,of ,,storms4 ,by ,william ,radcliffe ,birt4 #es4 ,a ,,naval ,,and ,,military ,,technical ,,dictionary ,,of ,,the ,,french ,,language4 ,by ,colonel ,burn1 ,r4,a4 #eth ,edition4 #aes4 ,,navigation ,,and ,,nautical ,,astronomy4 ,by the ,rev4 ,r4 ,m4 ,inskip1 ,c4,b4 #fs4 #f;d4 ,,norie',s ,,complete ,,epitome ,,of ,,practical ,,navigation4 ,illustrated by several ,engravings4 #bjth ,edition4 #afs4 ,,how ,,to ,,find ,,the ,,stars1 ,,and ,,their ,,use ,,in ,,determining ,,latitude1 ,,longitude1 and ,,the ,,error ,,of ,,the ,,compass2 ,illustrated with ,woodcuts1 and four large ,maps of the ,stars4 ,by ,w4 ,h4 ,rosser4 #gs4 #f;d4 ,,ganot',s ,,elementary ,,treatise ,,on ,,physics4 ,illustrated by #d ,colored ,plates and #geh woodcuts1 #aes4 ,,ganot',s ,,natural ,,philosophy4 #gs4 #f;d4 ,,the ,,heavens4 ,an ,illustrated ,handbook of ,popular ,astronomy4 ,by ,amede ,guillemin4 #abs4 ,,the ,,forces ,,of ,,nature4 ,by ,amede ,,guillemin4 ,illustrated by #aa colored plates and #dee woodcuts4 #a #as4 ,,deschanel',s ,,natural ,,philosophy4 ,by ,professor ,everett4 #ahs4 ,,physical ,,geography ,,in ,,its ,,relation ,,to ,,the ,,winds ,,currents4 ,by ,j4 ,k4 ,laughton1 ,m4,a4 #ajs4 #f;d4 ,,jeans' ,,navigation ,,nautical ,,astronomy4 ,price #ads4 ,,part ,i4--,containing ,rules and ,examples4 #gs4 #f;d4 ,,part ,,ii4--,investigations and ,proofs of ,rules4 #gs4 #f;d4 ,,regulations ,,for ,,preventing ,,collisions ,,at ,,sea4 #as4 ,,the ,,universal ,,code ,,of ,,signals of the ,mercantile ,marine of all ,nations4 ,by ,g4 ,b4 ,richardson4 #abs4 ,,contributions ,,to ,,solar ,,physics4 ,by ,norman ,lockyer1 ,f4,r4,s4 #cas4 #f;d4 ,,jeans' ,,handbook ,,of ,,the ,,stars4 #ds4 #f;d4 ,,half ,,hours ,,with ,,the ,,stars4 ,by ,proctor4 #es4 ,,ainsley',s ,,guide to the ,examinations of the ,local ,marine ,board4 #fs4 ,,sails ,,and ,,sail ,,making1 ,,with ,,draughting1 ,c4 ,by ,robert ,kipping1 #bs4 #f;d4 ,,evans' ,,elementary ,,manual for the ,deviation of the ,compass in ,iron ,ships4 #ds4 #f;d4 ,,the ,,marine ,,steam ,,engine4 ,by ,maine and ,brown4 #abs4 #f;d4 ,,spon',s ,,tables ,,and ,,memoranda for ,engineers4 #as4 ,,molesworth',s ,,engineer',s ,,pocket ,,book4 #fs4 ,,proctor',s ,,pocket ,,book ,,for ,,marine ,,engineers4 #ds4 ,,the ,,nautical ,,almanac4 #cs4 ,,masting1 ,,mast-,,making1 and ,,rigging ,,of ,,ships 1 with ,tables of ,spars1 c4 ,by ,robert ,kipping4 #bs4 ,griffin ,co41 ,publishers1 #b1 ,the ,hard1 ,portsmouth4 99 99 99 99 99 ,transcriber's ,notes3 ,obvious punctuation errors have been repaired4 ,varied hyphenation was retained4 ,the errors noted in the book's errata section have been repaired in the text except for the final one for page #bhe where the transcriber could not find a e to change to a d at that location4 ,text uses both fuse and fuze4 ,fuze is usually used in the ,english language to mean more complicated fuses4 ,inconsistencies in italic usage was retained4 ,for example1 on page #ih1 ,r is referenced originally without italics in an equation and after on the same page is italicized when mentioned4 ,page #ag1 principle changed to principal 7principal ones being7 ,page #gg1 #af' changed to #af 7about #af long1 #i deep7 ,page #aad1 ,northerners' changed to ,northerners' 7most of the ,northerners' vessels7 ,page #acb1 torpedos changed to torpedoes 7,whitehead's fish torpedoes have7 ,page #acd1 #ad changed to #adj 7#adj atmospheres7 ,page #afb1 equal sign added to equation 77#cad #bjj7 _/ #aif #cbj lbs7 ,page #afh1 ,,thornicroft',s changed ,,thornycroft',s on ,plate ,,xlvii4 ,page #agj1 ,,thornicroft',s changed ,,thornycroft',s on ,plate ,,xlviii4 ,page #aii1 ,poustchin changed to ,poutschin 7,alongside ,poutschin remained for some7 ,page #bjh1 spaces changed to space 7intervening space of7 ,page #bab1 subscript for ,o in chemical formula was unreadable4 #e was presumed and added4 7the formula ,,ch#g7,,no#b7c,o#e7 ,page #bdj1 ,seimens changed to ,siemens 7due to both ,dr4 ,siemens7 ,page #bda1 ,seimens changed to ,siemens 7that the ,siemens machine7 ,page #bga1 this paragraph seems to be missing a word but was retained as printed as the word could not be presumed by research4 ,oxygen is the most important element of an electrolyte1 and to the affinity for oxygen of the metals is the magnitude of the result and effect4 ,page #bih1 ,calland changed to ,callaud 7,calland and ,mari-,davy7 ,page #cjb1 dislectric changed to dielectric 7,gutta-percha as a dielectric7 ,page #aa1 advertising page1 ,portsmouth4 added to publisher line at bottom of page4 ,original ended with 7,griffin ,co ,publishers1 #b1 ,the ,hard17