,illustration ,,scientific ,,american ,,supplement ,,no4 #gii ,,new ,,york1 ,,april #be1 #ahia ,scientific ,american ,supplement4 ,vol4 ,,xxxi1 ,no4 #gii4 ,scientific ,american established #ahde ,scientific ,american ,supplement1 #e a year4 ,scientific ,american and ,supplement1 #g a year4 99 99 99 99 99 ,,table ,,of ,,contents4 ,i4 ,,architecture4--,marble and ,mosaic4--,by ,t4,r4 ,,spence4--,a paper recently read before the ,architectural ,association1 ,london1 containing valuable suggestions for designers of buildings4 ,the ,st4 ,lawrence ,hospital for the ,insane4--,a ,new ,york ,state hospital recently built from designs by the ,state architect4--,full description4--#a illustration4 ,,ii4 ,,botany4--,lavender and its ,varieties4--,the history1 properties1 and technology of this plant4--#b illustrations4 ,,iii4 ,,chemistry4--,a ,projecting ,apparatus of ,precision4--,a useful adjunct for the chemist's balance1 accelerating the operation of weighing4--#a illustration4 ,spectrum of the ,sun and ,elements4 ,allotropic ,forms of ,metals4 ,,iv4 ,,hydraulics4--,the ,power of ,water1 or ,hydraulics ,simplified4 --,by ,g4,d4 ,,hiscox4--,current wheels for power and raising water4 ,interesting presentation of this practical portion of the subject4 --#d illustrations4 ,v4 ,,mechanical ,,engineering4--,compressed ,air ,production4-- ,by ,,wm4 ,l4 ,,saunders4--,a ,sibley ,college lecture1 giving full elaboration to this important subject4--,the various forms of compressors and general features of the service4--#ah illustrations4 ,improved ,pneumatic ,hammer4--,a suspension hammer capable of delivering #ejj blows per minute4--#h illustrations4 ,the ,thermic ,motor of the ,future8--,a remarkable exposition of the possibilities of the gas engine4--,recent experiments under ,m4 ,aime ,witz4--#b illustrations4 ,,vi4 ,,medicine ,,and ,,hygiene4--,the ,electrical ,purification of ,sewage and ,contaminated ,water4--,by ,,wm4 ,,webster4 ,,vii4 ,,naval ,,engineering4--,the ,new ,german ,dispatch ,boat ,meteor4--,a ,german built war vessel of great speed4--,her dimensions and rating4--#a illustration4 ,the ,raising of the ,ulunda4--,a remarkable feat4--,the raising of a steamship sunk off ,nova ,scotia4--#aj illustrations4 ,,viii4 ,,technology4--,starches for the ,finishing of ,cotton ,fabrics4 --,classification of starches1 with illustrations of their appearance under the microscope4 ,,the ,,new ,,german ,,dispatch ,,boat ,,meteor4 ,in time of war the dispatch boats are the eyes of the fleet4 ,it is their duty to reconnoiter and ascertain the strength of the enemy and to carry the orders of the commander4 ,for this service great speed is of the utmost importance4 ,as all nations have increased the speed of their war ships during the last few years1 it has become necessary to build faster dispatch boats4 ,although our new vessels of this class1 ,blitz1 ,pfeil1 ,greif1 ,jagd1 and ,wacht1 fulfill the requirements1 still greater speed was deemed requisite1 and steps were taken for the construction of the ,meteor1 which was launched at ,kiel in #ahij4 ,this vessel is #bfb ft4 long1 #ca ft4 wide1 and has a draught of #ac ft41 and a displacement of #iej tons4 ,there are two independent engines1 each of which develops #b1ejj h4p41 making a total of #e1jjj h4p42 and each engine drives a screw4 ,when both engines are running with their full power1 the ,meteor has a speed of #bd knots 7over #bg miles7 an hour1 which is equal to the speed of a freight train4#a ,as the resistance of the water increases greatly with an increase in the speed of the vessel1 the engines of the ,meteor are very large in comparison with the size of the vessel4 ,the largest armored vessel in the navy1 the ,konig ,wilhelm1 for example1 has a displacement of #i1eeg tons1 and its engines develop #h1jjj h4p41 driving the vessel at a rate of #ad knots an hour2 that is1 #j4hd h4p4 to each ton of displacement1 while in the ,meteor there is #e4bf h4p4 to each ton of displacement4 ,the ,meteor has a crew of #ij men1 and an armament of eight light guns1 and has no rigging2 only one mast for signaling4 ,steam power is used for raising the anchor1 removing the ashes from the engine room1 and for distilling water4 ,the vessel is lighted with electricity1 and is also provided with electrical apparatus for search lights4--,illustrirte ,zeitung4 ,footnote #a3 ,this1 we believe1 is the fastest vessel of the kind afloat4--,,ed4 ,s4,a4 ,illustration3 ,,the ,,new ,,german ,,dispatch ,,boat ,,meteor4 99 99 99 99 99 ,,the ,,raising ,,of ,,the ,,ulunda4 ,shortly after the recovery of the ,ulunda1 below described1 the ,north ,american and ,west ,indian squadron of the ,royal ,navy visited ,halifax1 ,nova ,scotia4 ,the simple and novel means adopted for raising the ship attracted considerable attention among the officers of the fleet1 and by way of stimulating the studies of the junior officers in this branch of their duties1 a prize was offered for the best essay on the subject1 to be competed for by the midshipmen of the various ships4 ,the essays were adjudicated upon by ,captain ,w4,g4 ,stopford1 of the flag ship--,h4,m4,s4 ,bellerophon--and the first prize was awarded to the following paper1 written by ,mr4 ,a4 ,gordon ,smith1 of ,h4,m4,s4 ,canada4 ,the article needs no apology1 but it is only just1 says the ,engineer1 to mention the fact that the writer is not yet eighteen years of age4 ,the steamship ,ulunda1 on the remarkable raising and recovery of which this paper is written1 is an iron screw ship of #a1afa tons1 until lately belonging to the ,furness line4 ,it is a sister ship to the ,damara1 of the same company1 and was built and engined by ,alex4 ,stephens1 shipbuilder and engineer1 at ,glasgow1 being fitted with compound vertical engines1 of #bjj nominal horse power1 having two cylinders of #cc inches and #ff inches diameter respectively1 which are capable of sixty-five revolutions per minute1 and give a speed of twelve knots an hour4 ,for supplying steam to the engines there are two return-tube boilers1 each having three furnaces1 and there is also a donkey boiler1 which is used in harbor for working the four steam winches on deck4 ,she is divided into seven watertight compartments by athwartship bulkheads4 ,the foremost one is the usual collision bulkhead4 ,between this and the foremost engine room bulkhead are ,nos4 #a and #b holds1 separated by a watertight bulkhead4 ,abaft the after engine room are two more holds1 divided in the same manner as the forward ones1 and astern is another compartment1 in which all stores are kept4 ,coal bunkers form a protection for the engines and boilers4 ,fore and aft the ship1 as low down as possible1 are a number of ballast tanks1 which can be filled with or emptied of water as occasion requires to alter the trim of the ship4 ,extending over all holds there is a strong iron lower deck1 about #h feet below the upper deck1 which is pierced with a hatch over each hold immediately under a corresponding hatch in the upper deck1 for stowing and unstowing cargo4 ,illustration ,in the engine room there are six steam pumps1 two of them bilge pumps1 worked by the main crossheads1 for clearing the engine room of water4 ,for pumping out the ballast tanks there are two more1 which have their own independent engines4 ,the remaining two are for various purposes4 ,besides these there are several hand pumps on the upper deck4 ,having been built in #ahhe1 the ,ulunda is almost a new ship1 and has been used principally as a cargo steamer1 though she is provided also with a saloon and staterooms for a few passengers4 ,she was on her way from ,st4 ,john1 ,new ,brunswick1 to ,halifax1 when during a thick fog she struck on ,cowl ,ledge1 a reef between ,bryer and ,long ,islands1 on the southwest coast of ,nova ,scotia1 about half a mile from the shore4 ,the cause of the disaster was probably one of the strong tide eddies which exist in the ,bay of ,fundy1 and which had set her in toward the shore4 ,it was calm at the time1 and she was making seven knots an hour2 and1 being close to the shore1 leads should have been going in the chains4 ,had this precaution been taken1 very probably she would have been able to stop or anchor in time to avert this catastrophe4 ,there was no cargo on board1 it being intended to ship one at ,halifax for ,london4 ,when ashore on this reef she was sold by public auction at ,halifax1 and fell to a syndicate of private individuals for #ddj4 ,these gentlemen at once decided to raise her if possible1 transport her into dock1 and repair her4 ,they commissioned ,captain ,kelly1 of the ,princess ,beatrice1 a ship then in harbor1 to visit her and see what could be done for that purpose4 ,he went with a hired crew to ,annapolis1 and from thence proceeded to the steamer by means of a tug1 a distance of about forty miles4 ,when they arrived they found the ,ulunda with her head to sea1 and her stern in only #b ft4 of water at low tide1 with a list of #cj deg4 to port and her foremast broken short off4 ,at high tide the water flowed over the upper deck4 ,on examination1 the engine room was found full of water1 which did not rise and fall with the tide1 showing that it had been filled at high tide through its skylight4 ,no4 #c hold was also full1 but had a slight leak1 which was shown by the water falling slowly at low tide and rising in the same manner at high water4 ,the other three holds were hopelessly leaky4 ,upon investigation1 it was decided to pump out the engine room compartment and ,no4 #c hold1 and to make the iron lower deck watertight over the remaining holds4 ,for this purpose three powerful pumps1 with the necessary boilers1 were obtained from ,halifax1 sent by rail to ,annapolis1 and then shipped on board a tug1 from which they were hoisted into the ,ulunda by means of the derricks on the mainmast4 ,these were centrifugal pumps1 capable of discharging #b1jjj gallons a minute each4 ,one was placed in the engine room1 another with its suction in ,no4 #c hold1 and when these two compartments were pumped dry1 it was found that in ,no4 #c hold the leak was easily kept under1 while in the engine room there was no leak at all4 ,the third pump was not used4 ,illustration ,in the two foremost holds #b1jjj large casks were then placed1 and all the hatches over the leaky holds--,nos4 #a1 #b1 and #d--were battened down1 and made airtight with felt1 pitch1 tow1 etc4 ,a small hole was then made in ,nos4 #a and #b hatches1 about #b ft4 square4 ,when the tide had sunk its farthest1 these two holes were closed and made perfectly airtight1 in the same manner as the hatches had been4 ,before this took place the whole of the lower deck over the badly damaged holds had been prevented from bursting up by means of wooden shores1 which were placed in rows about #d ft4 apart1 and wedged firmly into position4 ,the wood for the shores was obtained from ,annapolis1 and the casks from ,st4 ,john4 ,the ship went ashore on ,august #bf1 #ahij4 ,this work was commenced on ,september #h1 and completed ten days afterward4 ,the labor of repairing her could only be carried out at low tide1 and only then with the greatest difficulty1 as the decks were very slippery with weeds1 etc41 and inclined at an angle of #cj deg4 ,everything was ready for floating her off at high tide on the #ahth1 and the hatches were closed up on that day4 ,she was raised off the rocks by the water rising and compressing the air in the two foremost holds1 assisted by the buoyancy of the engine room and ,no4 #c compartments4 ,at high water the bow was afloat1 but she was aground by the stern4 ,when1 however1 she was taken in tow by three tugs1 she slowly slid down the reef and floated into deep water4 ,one tug was placed on each bow1 and the third was ahead4 ,in this state she was towed into ,west ,port1 a distance of four miles1 and there beached on a sheltered stretch of sand4 ,the casks performed no part in floating the ship off1 but were only there in case the great pressure of air should cause the escape of some of it1 in which event all the space underneath the lower deck would soon have been occupied with water instead of air4 ,these casks would then1 of course1 have served to displace a large amount of this water1 and so keep her afloat4 ,luckily the deck did not leak1 and the barrels were thus not instrumental in the raising4 ,when beached the hatches were taken off1 the casks removed1 and a false deck was built about #g ft4 below the lower deck1 and about #aj ft4 above the keel4 ,this was used as the bottom of the ship to take her round to ,halifax1 and was built in the following manner3 ,a kind of iron platform1 about #b ft4 wide1 runs along the sides of the holds in the ,ulunda for strengthening purposes1 braced at intervals of #ae ft4 by iron beams across the ship4 ,on this was built the wooden deck4 ,beams for this deck were constructed of three #c in4 planks1 and were laid down on the iron platform about #c ft4 apart1 and firmly wedged into the ship's side4 ,on these beams a layer of #c in4 planks was placed in a fore-and-aft direction and nailed down2 on this were three layers of felt1 and on this again more planks were laid down in the same direction as before4 ,the whole deck was then carefully calked and the sides made watertight with ,portland cement4 ,this deck only extended to the engine room bulkhead through the two foremost holds4 ,it was prevented from bursting up by the pressure on the bottom of it1 by means of shores1 in the same manner as the iron deck had been served before4 ,shores were1 therefore1 connecting the three decks--the upper deck1 lower deck1 and wooden deck--this being done to equalize the pressure on the extempor deck and the two permanent decks1 and thus gain additional strength4 ,no deck was built in either of the after compartments1 inasmuch as ,no4 #c hold was kept clear of water as before by its pump1 and in ,no4 #d the deck was not necessary4 ,to have built one there1 as in the two foremost ones1 although it would have given a little more reserve of buoyancy to the ship1 would have raised the stern higher than the bows1 and so would have increased the upward pressure on the wooden deck1 and thus have increased the liability to burst up4 ,for the same reason1 when raising the ship off the rocks1 no compressed air was used in the after hold to lift the ship4 ,the anchors and cables were in both cases transferred aft1 for the same purpose1 namely1 to diminish the upward pressure forward4 ,in the case of the wooden deck leaking1 #bjj of the same casks were placed between it and the lower deck in the foremost hold to retain some of the buoyancy of the forepart1 which would otherwise be lost4 ,no decks were built in the compartment before the collision bulkhead1 as very little buoyancy was lost by that space being full of water1 and all that was there was confined to that compartment by the bulkhead and the iron lower deck4 ,while all these foregoing arrangements were being made for the exclusion of water from the inside of the ship1 the engineers and firemen were employed clearing the engine room of some fifty tons of coal which had been washed from the open bunkers into the machinery by the sea1 when the engine room was full and the ship on the reef4 ,the greatest difficulty was experienced in digging out and excavating the engines from the coal and dirt1 and still greater was the labor of cleaning all the mechanism and putting everything once more in an efficient steaming condition4 ,but all was finished soon after the decks had been completed1 and on ,october #ab she was ready for sea4 ,on the following day she was floated off and started on her perilous voyage to ,halifax1 using her own engines1 and making about five and a half knots an hour4 ,her steam pumps were by this time all ready for service to assist the big ones on deck in an emergency4 ,she anchored once on her way round1 at ,shelburne1 on the coast of ,nova ,scotia1 arriving at ,halifax at #a p4m4 on ,october #ag4 ,the trip round was a very anxious time for all hands1 more especially when they were overtaken by a fresh gale in the ,atlantic1 for the forward deck was very liable to be burst up with the increased pressure on it caused by the pitching of the ship2 also the rudder was entirely unable to bear any strain on it1 because the lower part of the rudder post was unconnected with the stern post1 part of the stern framing which connects the two having been broken off4 ,any heavy sea was therefore likely to carry away the rudder altogether1 or the same accident might happen if the helm was put down too hard1 rendering the ship unmanageable4 ,she was placed in dry dock as soon as she arrived at ,halifax1 and it was not until then that the full extent of the damages1 caused by the pounding on the rocks1 could be fully realized4 ,the first #bj feet of the keel had been torn completely out1 and about #cj feet from the stern there was an immense hole1 with the thick plates torn and bent like paper1 the framing and stanchions being twisted into all sorts of shapes almost beyond recognition4 ,under the foremast the bottom of the ship was bent up in the form of an arch1 having been raised #d feet above its natural position1 with an immense hole punctured on the starboard side1 besides several smaller ones4 ,also the aftermost #bj feet of keel was torn and jagged1 with several small holes in the skin1 and the lower portion of the stern framing was broken off1 leaving the rudder post to hang down unsupported at its extremity4 ,it would strike one on looking at these gaping wounds that it would be nearly impossible to place the ,ulunda in an efficient condition again1 but the work of renewing the damaged plates is being carried out at a great rate1 and in three months' time it is hoped that all the repairs necessary will be completed and the ship once more doing her duty4 ,she has already cost her owners some #aj1jjj1 and #dj1jjj are estimated to cover all future repairs4 ,the foremast was snapped off in a somewhat novel manner4 ,she was pivoted on the rocks by her bows1 and at high tide1 the day after she struck1 a breeze sprang up and turned her round2 the tide sinking again1 the whole weight of the ship came on the bottom of the ship where she was then touching1 namely1 just on the spot where the foremost was stepped1 and right astern1 leaving the center portion of the ship unsupported4 ,this caused the foremast to rise1 and it being held down by wire rigging1 it snapped in several places1 at the same time tearing up the shrouds from the deck4 ,this accounts also for the arch-like bulge in the bottom at that spot and for the damages astern2 also for the fact that ,captain ,kelly discovered the ship with her head to sea4 ,another incident happened when the ship was just rising off the rocks1 which nearly resulted in a catastrophe4 ,when the ship was just beginning to lift1 the leak in ,no4 #c compartment was found to be gaining on its pump4 ,a diver was at once sent down to ascertain the cause1 and he found that a small hole1 about #f inches square1 had been punctured in the skin1 which until then had been kept tight by the rock that had caused it4 ,it was necessary to close this leak at once4 ,an iron bolt1 which was screwed for a nut at one end1 was obtained and passed through a strong piece of wood about #b feet square4 ,the inside of this board was cushioned with canvas and oakum1 and it was taken down outside the ship by the diver and placed over the hole1 with the feathered end of the bolt sticking through the hole2 the diver was then sent down inside the hold1 and with a nut set up the whole cushion until the flow of water was stopped4 ,the leak was thus stopped which had threatened the arrangements for floating the ship with failure4 ,it has been seen that the method of raising the ,ulunda was very simple4 ,she was floated off by the rising tide4 ,if there had been only a small instead of an #ah foot rise1 some other mode would have to have been adopted4 ,no attempt was made to stop any of the leaks1 except the one just stated1 but a deck above the lacerations was made water-tight1 and this1 together with the sides of the ship hanging down1 formed a kind of diving bell1 the pressure of air in which1 caused by the water outside1 acting on this deck1 being the principal means of buoying up the ship1 assisted by the buoyancy of the two water-tight compartments4 ,the deck afterward built was only necessary for the safety of the ship1 she being able to float without it2 but it would have been suicidal to trust the ship on the ,atlantic in the state she was in when raised1 since with any swell on1 the compressed air would escape and its place be taken by water1 the buoyancy necessary for keeping her afloat being thus lost4 ,it only remains to be said that the risks run in steaming around to ,halifax by herself were1 as it was1 very great1 and had the wind and sea been less favorable1 the undertaking would probably have proved a disastrous failure4 99 99 99 99 99 ,,the ,,thermic ,,motor ,,of ,,the ,,future8 ,up to recent years there was no reason for putting the question that forms the title of this article1 for it was admitted by all that the conversion of thermic energy1 or heat produced by the combustion of coal1 into mechanical energy or work could no longer be effected economically except by having recourse to steam4 ,in ordinary language1 and even to manufacturers1 steam engine was the equivalent of thermic motor1 and it would not have occurred to any one to use anything else but steam to effect the transformation4 ,the progress that has been made during the last twenty years in the thermatic study and construction of gas motors 7without speaking of hot air motors7 has shown that the use of steam is not absolutely indispensable for the production of work1 and it has demonstrated that1 as regards dynamic product1 the gas motor preserves the advantage1 although the relatively high price of the illuminating gas employed in the production of the motive power generally renders the use of this combustible more costly than steam1 especially for high powers4 ,the economic truth of twenty years ago1 when gas motors absorbed #a1ejj liters per horse hour and exceeded with difficulty an effective power of from #h to #aj horses1 has become less and less certain1 when the consumption has successively descended to #a1bjj1 #a1jjj1 #hjj and even to #fjj liters of gas per horse hour1 the power of the motors rising gradually to #be1 #ej and #ajj horses with a motor having a single cylinder of a diameter of #eg centimeters4 ,illustration3 ,,fig4 #a4--;,,corliss ,,engine ,,and ,,boiler ,,of #ajj ,,indicated ,h4,p4--,,elevation ,,and ,,plan4 ,a1 cylinder2 ,b1 condenser2 ,c1 boiler2 ,r1 feed water heater2 ,d1 chimney4 ,but these results did not suffice1 and it was desired to do better still by dispensing with the use of high priced illuminating gas4 ,an endeavor was made to obviate the difficulty by manufacturing a special gas for the motive power1 as steam is produced for the same object1 by distilling coal1 carbureting air1 producing water gas by the ,dowson process1 and by other equivalent processes4 ,the strides made in this direction were finally crowned with success1 and the results obtained in the recent experiments due to ,mr4 ,aim ,witz1 an undoubted authority in the matter1 permit of affirming that now and hereafter1 in many circumstances1 a gas generator supplying a gas motor will be able to advantageously dethrone a steam boiler supplying a steam engine of the same power4 ,these conclusions1 which tend to nothing less than to limit the reign of the steam engine1 are confirmed on the one hand by an experiment carried on for the last two years in the ,barataud flour mill of ,marseilles1 where a #ej h4p4 ,simplex motor has been running day and night for several months without stopping1 and consuming but about #ejj grammes of ,english anthracite per effective horse hour1 and1 on another hand1 by some personal experiments of ,mr4 ,witz's1 to which we shall shortly advert1 and whence there results a sensibly equivalent production for a motor of #ajj indicated h4p41 corresponding to a power of #ge effective horses4 ,before establishing1 with ,mr4 ,witz1 a comparison of the two systems in pressure1 steam or gas1 let us state in a few words in what the latter consists1 the steam engine and the boiler that supplies it being so well known that no description is necessary4 ,the ,dowson gas generator does not differ essentially from the numerous generators devised during recent years for the manufacture of gaseous combustibles1 the use of which is so often convenient4 ,the motor that it supplies is the most powerful single cylinder one that has hitherto been constructed4 ,it is of #ajj indicated h4p41 and its normal angular velocity is #ajj revolutions per minute4 ,on trial it has yielded #aab indicated h4p41 and #gf4h effective h4p41 corresponding to an organic rendering of #fi per cent4 ,this motor1 elaborated by ,messrs4 ,delamare-,bouteville ,malandin1 of ,rouen1 operates by compression and in four periods1 according to the ,beau de ,rochas cycle4 ,we give the aspect of it in ,fig4 #c4 ,in the first period the mixture of air and gas is sucked in1 in the second it is compressed1 in the third it is ignited1 and in the fourth the products of combustion are expelled4 ,illustration3 ,,fig4 #b4--,,simplex ,,motor1 ,,dowson ,,generator ,,of #ajj ,,indicated ,h4,p4--,,elevation ,,and ,,plan4 ,a1 cylinder2 ,b1 gas conduit2 ,c1 rubber pockets2 ,d4 gasometer2 ,e1 purifier2 ,f1 scrubber2 ,g1 hydraulic main2 ,h1 cooling pipe2 ,i steam injector2 ,k1 steam boiler and superheater2 ,l1 gas generator2 ,m1 charger2 ,n1 discharge of the motor4 ,ignition is effected electrically by a series of sparks playing between two platinum points in the slide valve1 and this permits of regulating the instant of ignition through the edges of the orifices4 ,the angular velocity is regulated by a ,watt's governor1 which secures an isochronism of the motion independently of the charge4 ,the setting in motion of so powerful an engine is effected very easily by means of an arrangement that permits of introducing into the cylinder1 while the piston is in the center of the stroke1 a mixture of air and gas whose pressure is sufficient at the arrival to expel the inert products4 ,after this the ignition takes place1 and the explosion is sufficient to set the motor in motion4 ,the trials made by ,mr4 ,witz with the motor represented in ,fig4 #c gave the following results1 deduced from an experiment of #fh hours4 ,the figures relate to one effective horse power1 measured with the brake upon the shaft of the motor4 ,consumption of anthracite4 #eaf grammes4 coke4 #if ,consumption of water for the injection of steam4 #j4dhg liters4 ,consumption of water for cooling the cylinder4 #ej4j ,consumption of oil for lubricating the cylinder4 #c4gd grammes4 ,consumption of grease4 #j4de ,consumption of gas reduced to #j ,c4 and to #gfj mm4 #b1cgj liters4 ,this last figure will appear very high1 but the fact must not be lost sight of that it is a question of poor gas1 the net cost of which varies between one and two centimes per cubic meter1 and the calorific power of which is but #a1dhg heat units per cubic meter of constant volume1 and supposing the steam condensed4 ,this combustion of #fab grammes of combustible per effective horse hour is remarkable1 and fully shows what may be expected of the gas motor supplied by a gas generator in putting to profit certain improvements that will hereafter be possible1 such1 for example1 as the lightening of the movable parts of the motor1 the bettering of its organic rendering 7now quite feeble71 the use of better oils1 the reduction of the consumption of water1 the superheating of the steam injected into the gas generator1 etc4 ,a well constructed steam engine1 carefully kept in repair and as much improved as it is possible to make it1 would certainly consume twice as much coal to produce the same quantity of effective work1 say at least #a1bjj grammes per horse hour4 ,but1 as has been objected with reason1 it does not suffice to compare the figures as to the consumption of fuel in order to institute a serious comparison between the steam engine and the motor using poor gas4 ,the gas generator requires the use of ,english anthracite1 while a steam boiler is heated with any kind of coal4 ,the prices of unity of weight are therefore very different4 ,moreover1 the gas motor necessitates an immense amount of water for the washing of the gas and the cooling of the cylinder1 through circulation in the jacket4 ,it is well to keep this fact in view4 ,on another hand1 the lubrification of the cylinders requires a profusion of oil whose flashing point must be at a very high temperature1 else it would burn at every explosion and fill the cylinder with coom4 ,such oil is very costly4 ,does not the expenditure of oil in large motors largely offset the saving in coal8 ,and then1 gas motors are sold at high prices1 as are gas generators1 and this installation necessarily requires the addition of a large gasometer1 scrubbers1 etc4 ,the wear of these apparatus is rapid1 and if we take into account the interest and amortization of the capital engaged1 we shall find that the use of steam is still more economical4 ,the obstruction caused by bulky apparatus is another inconvenience1 upon which it is unnecessary to dwell4 ,in a word1 the question is a very complex one4 ,we look at but one side of it in occupying ourselves only with the coal consumed1 and we shall certainly expose those who allowed themselves to be influenced by the seductive figures of consumption to bitter disappointment4 ,to answer such objections ,mr4 ,aim ,witz has established a complete parallel between the two systems1 in which he looks at the question from a theoretical and practical and scientific and financial point of view4 ,considered as a transformation apparatus1 a steam motor burning good ,cardiff coal in a ,galloway boiler with feed water heaters will consume 7with a good condensing engine utilizing an expansion of a sixth7 from #a1ajj to #a1bej grammes of coal per effective horse hour1 which corresponds to a rough coefficient of utilization of #i4g per cent4 ,a gas generator supplying a gas motor burning ,swansea anthracite and ,noeux coke1 medium quality1 will consume #eaf grammes of anthracite and #ij of coke to produce #b1cgj liters of gas giving #a1dhg heat units per cubic meter4 ,of the #c1ebd heat units furnished to the motor by the #b1cgj liters of gas1 the motor will convert #ah per cent4 into disposable mechanical work4 ,with the boiler1 the gross rendering of the whole is #g per cent4 ,with the gas generator it reaches #ab4g per cent4 ,from a theoretical point of view the advantage therefore rests with the gas generator and gas motor4 ,in order to compare the net cost of the units of work1 from an industrial point of view1 it is necessary to form estimates of installation1 costs of keeping in repair1 interest and amortization4 ,figs4 #a and #b represent1 on the same scale1 the installations necessary in each of these systems4 ,the legends indicate the names of the different apparatus in each installation4 ,the following table shows that1 as regards the surface occupied1 the advantage is again with the gas generator and gas motor3 ,steam ,engine4 ,gas ,motor4 ,surface covered4 #he sq4 m4 #gb sq4 m4 ,surface exposed4 #cc #dc --- --- ,total surface4 #aah #aae ,the estimates of installation formed by ,mr4 ,witz set forth the expense relative to the capital engaged exactly at the same figure of #cb1jjj francs for a motive power of #ge effective horses4 ,the expenses of keeping in repair1 interest1 etc41 summed up1 show that the cost per day of #aj hours is #dg4i francs for the steam engine and #ci4f for the gas motor1 say a saving of #h4c francs per day1 or about #b1ejj francs for a year of #cjj days' work4 ,the gas motor1 therefore1 effects a great saving1 while at the same time occupying less space1 consuming less water and operating just as well4 ,with ,mr4 ,witz we cheerfully admit all the advantages that he so clearly establishes with his perfect competency in such matters1 but there still remain two points upon which we wish to be enlightened4 ,are not the starting up1 the operation and the keeping in repair of a gas generator actually more complicated and more delicate than the same elements of a steam engine8 ,does not the poor gas manufactured in a gas generator present1 from a hygienic point of view1 danger sufficiently great to proscribe the use of such apparatus in many circumstances8 ,such are the points upon which we should like to be enlightened before unreservedly sharing ,mr4 ,witz's enthusiasm1 which1 however1 is justified1 economically speaking1 by the magnificent results of the experiments made by the learned engineer4--,la ,nature4 ,illustration3 ,,fig4 #c4--;,,gas ,,motor ,,of #ajj ,,indicated ,,horse ,,power4 99 99 99 99 99 ,,improved ,,pneumatic ,,hammer4 ,we publish illustrations of a ,thwaites suspension pneumatic power cwt4 hammer of a new design1 for planishing pipes and plates1 for which we are indebted to ,engineering4 ,as indicated in the perspective view 7,fig4 #a7 the mechanism is supported at the center of a cross girder resting on two cast iron square pillars1 box section1 each bolted down to the foundations by four #a in4 diameter bolts4 ,the measurements of these columns and girders are given in ,figs4 #b and #c1 the former an elevation of the hammer and the latter a plan1 partly in section1 of the cross girder1 while ,fig4 #d is a cross section showing the arrangements for operating the hammer4 ,in the center is a cast iron guide for working the ram1 the guide being extended on two sides to receive the disk crank journals1 #b in4 in diameter by #c in4 long4 ,the disk cranks are connected to a hollow steel ram by a connecting rod4 ,the ram is divided inside into two compartments1 each having a phosphor bronze air piston4 ,these are connected together by a steel piston rod1 the top air piston forming a connection for the small end of the connecting rod4 ,the outside diameter of the ram is #c in41 and the diameter of the air pistons #b in4 and #b-g_/h in4 respectively4 ,cottered into the bottom of the ram is a steel pallet holder with a dovetail1 so that the pallet can be renewed or exchanged for one of another shape when required4 ,keyed on to the crankshaft is a flanged pulley #aj in4 in diameter by #c in4 between flanges4 ,there is also an overhead countershaft with strap shifting arrangement4 ,at the side of one of the columns a hand lever and quadrant are provided1 as shown in the perspective view and in ,fig4 #b1 for working an arrangement for tightening the belt when the machine is working4 ,to this arrangement is connected a powerful brake which stops the machine in a few revolutions4 ,it will be seen that the brake is applied as the belt is slackened for stopping the machine4 ,for planishing pipes or tubes a long wrought iron mandrel is provided mounted on two cast iron carriages1 each having four flanged wheels for running on rails4 ,the hammer is arranged so that tubes #d feet in diameter can be worked for planishing plates4 ,a pallet is fastened on the top of one of the mandrel carriages1 ,figs4 #e to #h showing the details of the carriages4 ,the general dimensions are3 ,distance between pillars1 #f feet2 height under girder1 #e feet2 height from ground to top of mandrel1 #d feet #a in42 and length of stroke1 #e in4 ,this machine is capable of delivering #ejj blows per minute4 ,the constructors are ,messrs4 ,thwaites ,brothers1 ,limited1 ,bradford1 ,yorkshire4 ,illustration3 ,,fig4 #a4 ,illustration3 ,,suspension ,,pneumatic ,,power ,,hammer4 99 99 99 99 99 ,,sibley ,,college ,,lectures4--#ahij-ia4 ,,by ,,the ,,cornell ,,university ,,non-,,resident ,,lecturers ,,in ,,mechanical ,,engineering4 ,,compressed ,,air ,,production4 ,by ,,wm4 ,l4 ,,saunders1 ,c4,e41 of ,new ,york4 ,i cannot but realize as ,i stand before you that ,i would be very much more at home were ,i in your midst4 ,i feel but little older and so very much less wise than when ,i sat in the class room an undergraduate of the ,university of ,pennsylvania1 that ,i trust ,i may expect you to give me this afternoon1 not only your attention1 but your sympathy4 ,the present situation is not without suggestions of my own experience4 ,i recall a lecture in the ordinary course1 given by our professor of mining1 whose struggles with the ,english language were quite as conspicuous as were our efforts to tell what he was driving at4 ,he was describing an ordinary windlass hoist used at the shaft of a mine4 ,he said ,there is a windlass at de top of de shaft around which is coiled a rope1 on de two ends of which is fastened two er--er--pans1 one of which is a bucket and de oder a platform4 ,i mention this because ,i shall ask you to attribute my shortcomings in this lecture1 not so much to my lack of familiarity with my native tongue1 as to--well1 because ,i was not educated at ,cornell ,university4 ,we all know what free air is4 ,you who are privileged to live upon these beautiful hills overlooking ,ithaca and the lake1 doubtless know more about free air than we do who are choked in the dusty confines of ,new ,york ,city4 ,compressed air is simply air under pressure4 ,that pressure may be an active one1 as in the case of the piston of an air compressor2 or passive1 as with the walls of a receiver or transmission pipe4 ,it is usual to define compressed air as air increased in density by pressure1 but we know that we may produce compressed air by heat alone4 ,a simple illustration of this is the pressure which will blow a cork from an empty bottle when that bottle has been placed near the fire4 ,here we have pressure1 or compressed air1 in the bottle produced by heat alone4 ,having defined compressed air1 we must next define heat2 for in dealing with compressed air1 we are brought face to face with the complex laws of ,thermodynamics4 ,we cannot produce compressed air without also producing heat1 and we cannot use compressed air as a power without producing cold4 ,based on the material theory of heat1 we would say that when we take a certain volume of free air and compress it into a smaller space1 we get an increase in temperature because we have the heat of one volume occupying less space1 but no one at this date accepts the material theory of heat4 ,your distinguished director1 ,professor ,thurston1 in discussing ,steam and its ,rivals1 in the ,forum1 said3 ,the science of ,thermodynamics teaches that heat and mechanical energy are only different phases of the same thing1 the one being the motion of molecules1 and the other that of masses4 ,this is the accepted theory of heat4 ,in other words1 we do not believe that there is any such thing as heat1 but that what we call heat is only the sensible effect of motion4 ,in the cylinder of an air compressor the energy of the piston is converted into molecular motion in the air and the result1 or the equivalent1 is heat4 ,a higher temperature means an increased speed of vibration1 and a lower temperature means that this speed of vibration is reduced4 ,if ,i hold an open cylinder in my left hand and a piston in my right1 and place the piston within the cylinder1 ,i here have a confined volume of air at the temperature and the pressure of this room4 ,these particles of air are in motion and produce heat and pressure in proportion to that motion4 ,now if ,i press the piston to a point in the center of the cylinder1 that is1 to one-half the stroke1 ,i here decrease the distance between the cylinder head and the piston just one-half1 hence each molecule of air strikes twice as many blows upon the piston and head in traveling the same distance and the pressure is doubled4 ,we have also produced about #aaf degrees of heat1 because we have expended a certain amount of work upon the air2 the air has done no work in return1 but we have increased the energy of molecular vibration in the air and the result is heat4 ,but what of this heat8 ,what harm does it do8 ,if ,i instantly release the piston which ,i hold at one-half stroke it will return to its original position1 less only a little friction4 ,i have1 therefore1 recovered all1 or nearly all1 the power spent in compressing the air4 ,i have simply pressed a spring1 and have let it recover4 ,we see what a perfect spring compressed air is4 ,we see the possibility of expending one horse power of energy upon air and getting almost exactly one horse power in return4 ,such would be the case provided we used the compressed air power immediately and at the point where the compression takes place4 ,this is never done1 but the heat which has been boxed up#a in the air is lost by radiation1 and we have lost power4 ,let us see to what extent this takes place4 ,footnote #a3 ,i use material terms because they add to simplicity of expression and notwithstanding the fact that heat is vibration4 ,thirteen cubic feet of free air at normal temperature and barometric pressure weigh about one pound4 ,we have seen that #aaf degrees of heat have been liberated at half stroke4 ,the gauge pressure at this point reaches #bd pounds4 ,according to ,mariotte's law1 ,the temperature remaining constant1 the volume varies inversely as the pressure1 we should have #ae pounds gauge pressure4 ,the difference1 #i pounds1 represents the effect of the heat of compression in increasing the relative volume of the air4 ,illustration3 ,,fig4 #a43 ,,curves ,,of ,,compression ,,illustratedin ,,volumes1 ,,pressures1 ,,and ,,temperatures4 ,the specific heat of air under constant pressure being #j4bch1 we have #j4bch #aaf #bg4f heat units produced by compressing one pound or thirteen cubic feet of free air into one-half its volume4 #bg4f #ggb 7,joule's equivalent7 #ba1cjg foot pounds4 ,we know that #cc1jjj foot pounds is one horse power1 and we see how easily about two-thirds of a horse power in heat units may be produced and lost in compressing one pound of air4 ,i would mention here that exactly this same loss is suffered when compressed air does work in an engine and is expanded down to its original pressure4 ,in other words1 the heat of compression and the cold of expansion are in degree equal4 ,experiments made by ,m4 ,regnault and others on the influence of heat on pressures and volumes of gases have enabled us to fix the absolute zero of temperature as -#dfa degrees ,fahrenheit4 ,this point1 #dfa degrees below zero1 is the theoretical point at which a volume of air is reduced to nothing4 ,the volume of air at different temperatures is in proportion to the absolute temperature1 and on this basis ,box gives us the following table3 ,,table l4--,,of ,,the ,,volume ,,and ,,weight ,,of ,,dry ,,air ,,at ,,different ,,temperatures ,,under ,a ,,constant ,,atmospheric ,,pressure ,,of #bi4ib ,,inches ,,of ,,mercury ,,in ,,the ,,barometer 7,,one ,,atmosphere71 ,,the ,,volume ,,at #cb ,,fahrenheit ,,being #a4 ,temperature ,volume in ,weight of a in degrees4 cubic feet4 cubic foot in lb4 #cb #a4jjj #j4jhjg #db #a4jbj #j4jgia #eb #a4jda #j4jggf #fb #a4jfa #j4jgfa #gb #a4jhb #j4jgdg #hb #a4ajb #j4jgcc #ib #a4abb #j4jgbj #ajb #a4adc #j4jgjg #aab #a4afc #j4jfid #abb #a4ahd #j4jfhb #acb #a4bjd #j4jfga #adb #a4bbd #j4jffj #aeb #a4bde #j4jfdi #afb #a4bfe #j4jfch #agb #a4bhe #j4jfbh #ahb #a4cjf #j4jfah #aib #a4cbf #j4jfji #bjb #a4cdg #j4jfjj #bab #a4cfg #j4jeia #bcj #a4djd #j4jege #bej #a4ddd #j4jeei #bge #a4die #j4jedj #cjj #a4edf #j4jebb #cbe #a4eig #j4jejf #cej #a4fdh #j4jdij #cge #a4fhi #j4jdgg #djj #a4gej #j4jdfa #dej #a4heb #j4jdcf #ejj #a4ied #j4jdac #eej #b4jef #j4jchd #fjj #b4aea #j4jcgf #fej #b4bfj #j4jceg #gjj #b4cfb #j4jcch #gej #b4dfd #j4jcbh #hjj #b4eff #j4jcae #hej #b4ffh #j4jcjc #ijj #b4ggj #j4jbib #iej #b4hgb #j4jbha #a1jjj #b4igd #j4jbfh #a1ajj #c4agg #j4jbed #a1bjj #c4cha #j4jbci #a1cjj #c4ehe #j4jbbe #a1djj #c4ghi #j4jbac #a1ejj #c4iic #j4jbjb #a1fjj #d4aig #j4jaib #a1gjj #d4dja #j4jahc #a1hjj #d4fje #j4jage #a1ijj #d4hji #j4jafh #b1jjj #e4jab #j4jafa #b1ajj #e4baf #j4jaee #b1bjj #e4dbj #j4jadi #b1cjj #e4fbd #j4jadb #b1djj #e4hbh #j4jach #b1ejj #f4jcb #j4jacc #b1fjj #f4bcf #j4jacj #b1gjj #f4ddj #j4jabe #b1hjj #f4fdd #j4jaba #b1ijj #f4hdg #j4jaah #c1jjj #g4jea #j4jaad #c1ajj #g4bee #j4jaaa #c1bjj #g4dei #j4jajh ,transcribers note #a3 last digit illegible ,the effect of this heat of compression in increasing the volume1 and the heat produced at different stages of compression1 are shown by the following table3 ,,table #b4--;,,heat ,,produced ,,by ,,compression ,,of ,,air4 ---------------------------------------- -------------------------- ,pressure4 ,atmo- ---------------------- ,volume ,temperature ,total spheres4,pounds per ,pounds per in ,cubic of the ,air ,increase of ,square ,inch,square ,inch ,feet4 throughout ,temperature4 above a above the the ,process4 ,degrees4 ,vacuum4 ,atmosphere ,degrees4 7,gauge ,pressure74 ---------------------------------------- ------------------------- #a4jj #ad4gj #j4jj #a4jjjj #fj4j #jj4j #a4aj #af4ag #a4dg #j4icdf #gd4f #ad4f #a4be #ah4cg #c4fg #j4hecf #id4h #cd4h #a4ej #bb4je #g4ce #j4geja #abd4i #fd4i #a4ge #be4ha #aa4aa #j4fgbd #aea4f #ia4f #b4jj #bi4dj #ad4gj #j4faag #age4h #aae4h #b4ej #cf4gj #bb4jj #j4ebba #bah4c #aeh4c #c4jj #dd4aj #bi4dj #j4dehh #bee4a #aie4a #c4ej #ea4dj #cf4gj #j4daac #bhg4h #bbg4h #d4jj #eh4hj #dd4aj #j4cgda #cag4d #beg4d #e4jj #gc4ej #eh4hj #j4caid #cfi4d #cji4d #f4jj #hh4bj #gc4ej #j4bhjf #dad4e #ced4e #g4jj #ajb4ij #hh4bj #j4beaf #ded4e #cid4e #h4jj #aag4fj #ajb4ij #j4bbhh #dij4f #dcj4f #i4jj #acb4cj #aag4fj #j4baje #ebc4g #dfc4d #aj4jj #adg4jj #acb4cj #j4aiec #eed4j #did4j #ae4jj #bbj4ej #bje4hj #j4adfe #fha4j #fba4j #bj4jj #bid4jj #bgi4cj #j4aaie #gha4j #gba4j #be4jj #cfg4ej #ceb4hj #j4ajbj #hfd4j #hjd4j ---------------------------------------- ------------------------- ,a cubic foot of free air at a pressure of one atmosphere 7equal to #ad4g pounds above a vacuum7 at a temperature of #fj degrees1 when compressed to twenty-five atmospheres1 will register #cfg4e pounds above a vacuum 7#ceb4h pounds gauge pressure71 will occupy a volume of #j4ajbj cubic foot1 will have a temperature of #hfd degrees1 and the total increase of temperature is #hjd degrees4 ,the thermal results of air compression and expansion are shown by the accompanying diagram4 ,the horizontal and vertical lines are the measures of volumes1 pressures and temperatures4 ,the figures at the top indicate pressures in atmospheres above a vacuum1 the corresponding figures at the bottom denote pressures by the gauge4 ,at the right are volumes from one to one-tenth4 ,at the left are degrees of temperatures from zero to #a1jjj ,fahrenheit4 ,the two curves which begin at the upper left hand corner and extend to the lower right are the lines of compression or expansion4 ,the upper one being the ,adiabatic curve1 or that which represents the pressure at any point on the stroke with the heat developed by compression remaining in the air2 the lower is the ,isothermal1 or the pressure curve uninfluenced by heat4 ,the three curves which begin at the lower left hand corner and rise to the right are heat curves and represent the increase of temperature corresponding with different pressures and volumes1 assuming in one case that the temperature of the air before admission to the compressor is zero1 in another sixty degrees1 and in another one hundred degrees4 ,beginning with the adiabatic curve1 we find that for one volume of air when compressed without cooling the curve intersects the first vertical line at a point between #j4f and #j4g volume1 the gauge pressure being #ad4g pounds4 ,if we assume that this air was admitted to the compressor at a temperature of zero1 it will reach about #ajj degrees when the gauge pressure is #ad4g pounds4 ,we find this by following down the first line intersected by the adiabatic curve to the point where the zero heat curve intersects this same line1 the reading being given in figures to the left immediately opposite4 ,if the air had been admitted to the compressor at #fj degrees1 it would register about #agf degrees at #ad4g pounds gauge pressure4 ,if the air were #ajj degrees before compression1 it would go up to about #bcj degrees at this pressure4 ,following this adiabatic curve until it intersects line ,no4 #e1 representing a pressure of five atmospheres above a vacuum 7#eh4h lb4 gauge pressure71 we see that the total increase of temperature on the zero heat curve is about #bgj degrees1 for the #fj degree curve it is about #cgj degrees1 and for the #ajj degree curve it is about #dce degrees4 ,the diagram shows that when a volume of air is compressed adiabatically to #ba atmospheres 7#bid lb4 gauge pressure71 it will occupy a volume a little more than one-tenth2 the total increase of temperature with an initial temperature of zero is about #fej degrees2 with #fj degrees initial temperature it is #hjj degrees1 and with #ajj degrees initial it is #ijj degrees4 ,it will be observed that the zero heat curve is flatter than the others1 indicating that when free air is admitted to a compressor cold1 the relative increase of temperature is less than when the air is hot4 ,this points to the importance of low initial temperature4 ,we have now seen that the economical production of compressed air depends upon the following conditions3 7#a7 ,a low initial temperature4 7#b7 ,thorough cooling during compression4 ,it has been demonstrated by experiments made in ,france that the power required to compress moist air is less than that for dry air4 ,a table showing the power required to compress moist and dry air has been prepared from the data of ,m4 ,mallard and shows that for five atmospheres the work expended in compressing one pound of dry air is #eh1ejj foot pounds1 while that for moist air is #eb1ejj foot pounds4 ,in expansion also moisture in the air adds to the economy1 but in both cases the saving of power is not great enough to compensate for the many disadvantages due to the presence of water4 ,mr4 ,norman ,selfe1 of the ,engineering ,association of ,n4,s4,w41 has compiled a table which shows some important theoretical conditions involved in producing compressed air4 ,so much for the theory of compression4 ,we now come to the practical production of compressed air4 ,the first record that we have of the use of an air compressor is at ,ramsgate ,harbor1 ,kent1 in the year #aghh4 ,smeaton invented this pump for use in a diving apparatus4 ,in #ahea1 ,william ,cubitt1 at ,rochester ,bridge1 and a little later an engineer1 ,brunel1 at ,saltash1 used compressed air for bridge work4 ,but the first notable application of compressed air is due to ,professor ,colladon1 of ,geneva1 whose plans were adopted at the ,mont ,cenis tunnel4 ,m4 ,sommeiller developed the ,colladon idea and constructed the compressed air plant illustrated in ,fig4 #b4 ,illustration3 ,,fig4 #b4 ,the ,sommeiller compressor was operated as a ram1 utilizing a natural head of water to force air at #hj pounds pressure into a receiver4 ,the column of water contained in the long pipe on the side of the hill was started and stopped automatically1 by valves controlled by engines4 ,the weight and momentum of the water forced a volume of air with such shock against a discharge valve that it was opened and the air was discharged into the tank2 the valve was then closed1 the water checked2 a portion of it was allowed to discharge and the space was filled with air1 which was in turn forced into the tank4 ,the efficiency of this compressor was about #ej per cent4 ,at the ,st4 ,gothard tunnel1 begun in #ahgb1 ,prof4 ,colladon first introduced the injection of water in the form of spray into the compressor cylinder to absorb the heat of compression4 ,illustration3 ,,fig4 #c4 ,fig4 #c illustrates the air cylinder of the ,dubois-,francois type of compressor1 which was the best in use about the year #ahgf4 ,this compressor was exhibited at the ,centennial ,exposition and was adopted by ,mr4 ,sutro in the construction of the ,sutro tunnel4 ,a characteristic feature seems to be to get as much water into the cylinder as possible4 ,the water which flooded the bottom of the cylinder arose from the voluminous injection2 this water was pushed into the end of the cylinder and some of it escaped with the air through the discharge valve4 ,an improved pattern of this compressor is shown in ,fig4 #d4 ,illustration3 ,,fig4 #d4 ,these illustrations are interesting from an historical point of view1 as indicating the line of thought which early designers of air-compressing machinery followed4 ,as the necessity for compressed air power grew1 inventors turned their attention to the construction of air-compressing engines that would combine efficiency with light weight and economy of space and cost4 ,the trade demanded compressors at inaccessible localities1 and in many cases it was preferred to sacrifice isothermal results to simplicity of construction and low cost4 ,it is evident that an air compressor which has the steam cylinder and the air cylinder on a single straight rod will apply the power in the most direct manner1 and will involve the simplest mechanics in the construction of its parts4 ,it is evident1 however1 that this straight line1 or direct construction1 results in an engine which has the greatest power at a time when there is no work to perform4 ,at the beginning of the stroke steam at the boiler pressure is admitted behind the piston1 and1 as the air piston at that time is also at the initial point in the stroke1 it has only free air against it4 ,the two pistons move simultaneously1 and the resistance in the air cylinder rapidly increases as the air is compressed4 ,to get economical results it is1 of course1 necessary to cut off in the steam cylinder1 so that at the end of the stroke1 when the steam pressure is low1 as indicated by the dotted line 7,fig4 #e71 the air pressure is high1 as similarly indicated4 ,the early direct-acting compressor used steam at full pressure throughout the stroke4 ,the ,westinghouse pump1 applied to locomotives1 is built on this principle1 and those who have observed it work have perhaps noticed that its speed of stroke is not uniform1 but that it moves rapidly at the beginning1 gradually reducing its speed1 and seems to labor1 until the direction of stroke is reversed4 ,this construction is admitted to be wasteful1 but in some cases1 notably that of the ,westinghouse pump1 economy in steam consumption is sacrificed to lightness and economy of space4 ,illustration3 ,,fig4 #e4 ,many efforts were made to equalize the power and resistance by constructing the air compressor on the crank shaft principle1 putting the cranks at various angles1 and by angular positions of steam and air cylinders4 ,several types are shown in ,fig4 #f4 ,illustration3 ,,fig4 #f4 ,angular positions of the cylinder involve expensive construction and unsteadiness4 ,experience has conclusively proved that it does not pay to build air compressors with vertical cylinders1 and moreover we have found out that there is nothing in the apparent difficulty in equalizing the strains in a direct-acting engine4 ,it is simply necessary to add enough weight to the moving parts1 that is1 to the piston1 piston rod1 fly wheel1 etc41 to cut off early in the stroke and secure rotative speed with the most economical results and with the cheapest construction4 ,it is obvious that the theoretically perfect air compressor is a direct-acting one with a conical air cylinder1 the base of the cone being nearest the steam cylinder4 ,this1 from a practical point of view1 is impossible4 ,mr4 ,hill1 in referring to the fallacious tendencies of pneumatic engineers to equalize power and resistance in air compressors1 says3 ,the ingenuity of mechanics has been taxed and a great variety of devices have been employed4 ,it is usual to build on the pattern of presses which do their work in a few inches of the end of the stroke and employ heavy fly wheels1 extra strong connections1 and prodigious bed plates4 ,counterpoise weights are also attached to such machines2 the steam is allowed to follow full stroke1 steam cylinders are placed at awkward angles to the air-compressing cylinders and the motion conveyed through yokes1 toggles1 levers2 and many joints and other devices are used1 many of which are entire failures1 while some are used with questionable engineering skill and very poor results4 ,illustration3 ,,fig4 #g4 ,fig4 #g illustrates the theory of ,duplex ,air ,compressors4 ,the hydraulic piston or plunger compressor is largely used in ,germany and elsewhere on the ,continent of ,europe1 but the duplex may be said to be the standard type of ,european compressor at the present time4 ,it is also largely used in this country4 ,fig4 #g shows the four cylinders of a duplex compressor in two positions of the stroke4 ,it will be observed that each steam cylinder has an air cylinder connected directly to the tail rod of its piston1 so that it is a direct-acting machine1 except in that the strains are transmitted through a single fly wheel1 which is attached to a crank shaft connecting the engines4 ,in other words1 a duplex air compressor would be identical with a duplex steam engine were it not for the fact that air cylinders are connected to the steam piston rods4 ,the result is1 as shown in ,fig4 #g1 that1 at that point of the stroke indicated in the top section1 the upper right hand steam cylinder1 having steam at full pressure behind its piston1 is doing work through the angle of the crank shaft upon the air in the lower left hand cylinder4 ,at this point of the stroke the opposite steam cylinder has a reduced steam pressure and is doing little or no work1 because the opposite air cylinder is beginning its stroke4 ,referring now to the lower section1 it will be seen that the conditions are reversed4 ,one crank has turned the center1 and that piston which in the upper section was doing the greatest work is now doing little or nothing1 while the labor of the engine has been transferred to those cylinders which a moment before had been doing no work4 ,there are some advantages in this duplex construction1 and some disadvantages4 ,the crank shafts being set quartering1 as is the usual construction1 the engine may be run at low speed without getting on the center4 ,each half being complete in itself1 it is possible to detach the one when only half the capacity is required4 ,the power and resistance being equalized through opposite cylinders1 large fly wheels are not necessary4 ,strange to say1 the ,american practice seems to be to attach enormous fly wheels to duplex air compressors4 ,it is difficult to justify this apparently useless expense in view of the facts shown in ,fig4 #g4 ,a fly wheel does not furnish power1 nor does it add to the economy of an engine except in so far as it enables it to cut off early in the stroke1 and to equalize the power and resistance4 ,in other words1 a fly wheel is not a source of power1 and in many cases it is only a means by which we accomplish rotative speed4 ,it takes power to move matter1 and assuming that other conditions are equal1 every engine that carries a fly wheel that is larger than is necessary consumes a certain number of foot pounds in turning so much metal around through space4 ,were it possible to cut off at the same point and rotate as positively without a fly wheel1 it would be done away with entirely4 ,some straight line air compressors are so constructed that the momentum of the piston and other moving parts is nearly sufficient to equalize the strains without a fly wheel2 but the fly wheel is there because it insures a definite length of stroke1 and because it enables us to operate eccentrics and to regulate the speed of the engine uniformly4 ,objections to the duplex construction are3 ,the strains are indirect1 angular and intermittent4 ,it is necessary therefore to largely increase the strength of parts2 to add a crank shaft of large diameter with enormous bearings1 and to build expensive and very secure foundations4 ,should the foundations settle at any point1 excessive strains will be brought upon the bearings1 resulting in friction and liability to breakage4 ,a steam engine meets with a resistance on its crank shaft that is uniform throughout the stroke2 while an air compressor is subject to a heavy maximum strain at the end of the stroke1 hence the importance of direct straight line connection between power and resistance4 ,illustration3 ,,fig4 #h4 ,the friction loss on a duplex compressor seldom gets lower than #ae per cent41 while straight line compressors show as low a loss as #e per cent4 ,fig4 #h illustrates the ,rand ,duplex ,air ,compressor1 a machine largely used in ,america1 especially in the ,lake ,superior iron mines4 ,fig4 #i illustrates a ,duplex ,compound ,condensing ,corliss ,air ,compressor built by the ,ingersoll-,sergeant ,drill ,company4 ,this is a compressor made of the best type of ,corliss engine1 with air cylinders connected to the tail rods of the steam cylinders4 ,one of these machines1 of about #djj horse power capacity1 is now at work furnishing compressed air power for the ,brightwood ,street ,railway in ,washington1 ,d4,c4 ,fig4 #aj illustrates the ,norwalk direct-acting straight line air compressor1 with compound air cylinder4 ,the chief purpose of compounding is to reduce the maximum strain4 ,this construction also adds to isothermal economy4 ,the large cylinder to the left determines the capacity of the compressor1 the air being compressed first to a low pressure 7ordinarily about #cj pounds per square inch71 afterward passing through an intercooler1 by which its temperature is reduced1 and then it is compressed still higher1 even to #e1jjj pounds per square inch if desired4 ,the terminal strain1 which is so severe in air compressors1 is here considerably reduced1 as in this case it is only equal to the area of the initial air piston multiplied by its low air pressure4 ,illustration3 ,,fig4 #i4 ,economical results are attained with this compressor at low cost of construction4 ,the fly wheels are small1 and the bearings narrow1 because the maximum strain is less1 and the momentum of the piston and other moving parts is such that most of the high initial steam power is taken up in starting these parts and is afterward given out at the end of the stroke1 when the steam pressure is low4 ,the strains are direct1 and expensive foundations are not required4 ,fig4 #aa illustrates the ,ingersoll-,sergeant ,compound ,straight ,line ,air ,compressor4 ,this differs from the one just described chiefly in that it is single-acting1 while the other is double-acting4 ,illustration3 ,,fig4 #aj4 ,by single-acting is meant that the air cylinders compress their respective volumes of air once every revolution4 ,the air is admitted to the large cylinder through the piston1 is compressed to about #cj pounds1 and on the return stroke the pressure is raised to almost any point required1 and in proportion to the diameter of the smaller cylinder4 ,though single-acting1 the capacity of one of these compressors is about equal to that of the double-acting machine of the same cost of construction4 ,the initial air cylinder is made large enough to correspond with the capacity of the smaller double-acting cylinder4 ,the strains are equalized because the area of the large cylinder multiplied by its low pressure is exactly equal to that of the small cylinder multiplied by its high pressure4 ,the maximum strains are reduced considerably below those which exist in compressors that do not compound the air4 ,illustration3 ,,fig4 #aa4 ,the advantage of the single-acting air cylinder over the double is that it compresses a volume of free air only once every revolution1 hence there is a better chance to cool the air during compression4 ,the cylinders have time to impart to the water jackets the heat produced by compression and are kept cooler4 ,the large air head of the initial cylinder is jacketed1 also adding to isothermal economy4 ,illustration3 ,,fig4 #ab4 ,fig4 #ab illustrates the ,ingersoll-,sergeant ,piston ,inlet ,cold ,air ,compressor4 ,this a straight line direct-acting engine1 with steam and air pistons connected to a single rod through a crosshead which connects with two fly wheels4 ,the strains are direct and the power and resistance are equalized by the inertia of the crosshead1 piston1 rods1 and fly wheels4 ,the ,meyer's adjustable cut-off is used on the steam cylinder4 ,the air cylinder is provided with a tail rod tube through which all the air is admitted into the cylinder4 ,illustration3 ,,fig4 #ac4--;,,an ,,automatic ,,and ,,adjustable ,,regulator ,,and ,,unloading ,,device ,,applied ,,to ,,ingersoll-,,sergeant ,,air ,,compressors4 ,fig4 #ac illustrates an unloading device and regulator applied to the ,ingersoll-,sergeant compressor4 ,the purpose of this unloading device is to maintain a uniform air pressure in the receiver and a uniform speed of engine1 notwithstanding the consumption of the air1 and to do this without waste of power or attention on the part of the engineer4 ,a weighted valve of safety valve pattern is attached to the air cylinder1 and is connected with the air receiver1 and with a discharge valve on each end of the air cylinder1 also with a balanced throttle valve in the steam pipe4 ,when the pressure of the air gets above the desired point in the receiver1 the valve is lifted and the air is exhausted from behind the discharge valves1 thus letting the compressed air at full receiver pressure into the cylinder at both ends1 and balancing the engine4 ,at the same instant the compressed air is exhausted from the little piston connected with the balanced steam valve and the steam is automatically throttled1 so that only enough steam is admitted to keep the engine turning around1 or to overcome the friction1 no work being done4 ,illustration3 ,,fig4 #ad4 ,when the compressor is unloaded1 it is evident that the function of the air piston is merely to force the compressed air through the discharge valves and passages from one end to the other until more compressed air is required1 this being indicated by a fall in the receiver pressure4 ,the weighted valve now closes and the small connecting pipes are instantly filled with compressed air2 the steam valve automatically opens1 and the compression goes on in the regular way4 ,another function of this device is to prevent the compressor from stopping or getting on the center4 ,direct-acting compressors are liable to center when doing work at slow speed4 ,illustration3 ,,fig4 #ae4 ,,piston ,,inlet ,,valve ,,operated ,,by ,,the ,,natural ,,laws ,,of ,,momentum4 ,fig4 #ae illustrates the ,ingersoll-,sergeant ,air ,cylinder and ,piston4 ,fig4 #af shows the piston inlet valve1 situated at ,g in ,fig4 #ae4 ,two of these valves are placed in each piston of a double-acting air cylinder1 the piston being hollow and the free air being admitted through a tail-rod pipe1 letter ,e1 ,fig4 #ae4 ,,jj are water jacket passages for cooling the air during compression4 ,owing to the absence of inlet valves1 large water jackets are provided1 not only around the cylinder itself1 but through the heads4 ,as the heat of compression is greater near the end of the stroke1 the advantage of a cool head is manifest4 ,h ,h are the discharge valves through which the compressed air is forced4 ,illustration3 ,,fig4 #af4 ,,piston ,,inlet ,,valve ,,operated ,,by ,,the ,,natural ,,laws ,,of ,,momentum4 ,the most interesting feature of this cylinder is the piston inlet valve4 ,it is evident that this valve being attached to the piston needs no springs or other connections1 but is opened and closed exactly at the right time by its natural inertia4 ,with only about of an inch throw of valve a large area is opened1 through which the free air is drawn4 ,the valve is made of a single piece of composition metal and is practically indestructible4 ,its construction is such that it fills the clearance spaces to a greater extent than is usual in air compressors4 ,a singular feature is that indicator cards taken on these cylinders show a free air line in some cases a little above the atmospheric line4 ,poppet valve compressors almost invariably show a slight vacuum1 due to several causes1 mainly the duty performed in compressing the springs of the valves1 but the vacuum is also influenced by insufficiency of valve area1 hot air cylinders1 etc4 ,this cylinder gives its full volume of air1 and apparently a little more at times1 because the air is admitted by a concentrated inlet in which free air is always moving in one direction4 ,after it has been started1 the speed of the compressor is such that the air attains a momentum due to its velocity and density2 this serves a useful purpose in piling up the free air in the cylinder before the inlet valve closes on the return stroke4 ,illustration3 ,,fig4 #ag4--;,,combined ,,steam ,,and ,,air ,,indicator ,,card3 ,taken from a #afx#ah ,sergeant piston inlet air compressor1 meyer's cut-off at #c_/aj4 ,steam at #eh lb42 air pressure1 #gg lb42 total engine friction1 #e per cent4 ,fig4 #ag illustrates a combined steam and air indicator card taken from one of these cylinders4 ,it will be observed that with steam and air cylinders equal in diameter and stroke1 an air pressure of #gg pounds is reached with a steam pressure of only #eh pounds4 ,the reason for this is plainly shown in the cards1 their areas being nearly equal4 ,what is made up in the air card by high pressure is represented in the steam card by greater volume4 ,the indicated efficiency deduced from these cards is #ie per cent41 that is1 the area of the air card divided by the area of the steam card1 representing the resistance divided by the power1 results in #ie per cent4 ,while several cards have been taken on the cylinders showing a loss by friction of only #e per cent41 yet on the average the best practice shows a loss of #f per cent4 or an efficiency of #id per cent4 ,this result indicates an almost perfect proportion between power and resistance1 and good workmanship in air-compressing machinery4 ,it is difficult to conceive an engine of this size being worked with a less expenditure for friction than #e or #f per cent4 ,were it possible to retain the heat which is in the air1 and which is represented by the space between the dotted isothermal curve and the actual curve1 we might attain high efficiency in using compressed air power1 but it is evident that the power represented by the area of this space will be lost by radiation of heat before it is used in an engine situated several hundred feet away4 ,these indicator cards show at a glance that heat is responsible for the important air losses1 and that so far as the design of the compressing engine is concerned1 we have attained a point very near perfection4 ,all the devices1 past1 present and future1 on which inventors spend so much time1 and in the development of which capitalists are innocently inveigled1 aim to save this six per cent4 loss6 ,we hear a good deal about ,centrifugal ,air ,compressors1 ,rotaries1 ,plunger ,pumps1 etc41 designs involving expensive complications without any heat advantage1 and which seem to be based upon the iridescent dream of a large loss in the present method of compressing air4 ,here we have a simple engine1 compact and complete in itself1 capable of high speed without injury1 constructed on the basis of our best steam engine practice1 which produces compressed air power at a loss of only six per cent4 ,clearance is not taken into consideration in the foregoing figures1 but clearance is very much more of a bete noir in theory than in practice4 ,the early designers1 as shown in the ,dubois-,francois illustrations1 ,figs4 #c and #d1 regarded clearance loss as a very serious matter4 ,even at the present time some air compressor manufacturers admit water through the inlet valves into the air cylinder1 not so much for the purpose of cooling as to fill up the clearance space4 ,a long stroke involving expensive construction is usually justified by the claim that a large saving is effected by reduced clearance loss4 ,let us see what the effect of this clearance is4 ,assuming that we have an air compressor which shows an isothermal pressure line1 there would be some loss of power due to clearance space1 because we would have a certain volume of air upon which work was done and heat produced1 that heat having been absorbed and the air being retained in the cylinder and not serving any useful purpose4 ,but let us assume that we have a compressor which shows an adiabatic pressure line4 ,we now have the air in the clearance space acting precisely as a spring1 compressed at each stroke1 retaining its heat of compression1 and giving it out against the air piston at the point when the stroke is reversed4 ,there is no loss of power in such a case as this1 but1 on the contrary1 the air spring is useful in overcoming the inertia of the piston and moving parts4 ,the best air compressors give a result about midway between the isothermal and the adiabatic1 and the net loss of power directly due to clearance is so small as to be practically unworthy of consideration4 ,it must not be inferred from the preceding remarks that the designer of an air compressor may neglect the question of clearance4 ,on the contrary1 it is a very important consideration4 ,if we assume a large clearance space in the end of an air cylinder of a compressor which is furnishing air at a high pressure1 we may readily conceive that space to be so large1 and that pressure so high1 that the entire volume of the cylinder would be filled by the air from the clearance space alone1 and the compressor would take in no free air and would1 of course1 produce no compressed air4 ,loss in capacity of air compressors by clearance is in direct proportion to the pressure4 ,owing to the loss of capacity by clearance space at high pressures1 it is important that compound air cylinders should be used for furnishing air at high pressure4 ,with compound air cylinders the air is compressed to alternate stages of pressure in the different cylinders1 and the clearance loss is thus reduced because of the reduced density of the air in the clearance spaces4 ,in ordinary practice air compressors deliver the air at less than #ajj pounds pressure1 so that with a properly designed air cylinder the clearance space is so small that the capacity of the compressor is not materially affected4 ,two systems are in use by which the heat of compression is absorbed1 and the difference between one and the other is so distinct that air compressors are usually divided into two classes 7#a7 wet compressors1 7#b7 dry compressors4 ,a wet compressor is that which introduces water directly into the air cylinder during compression4 ,a dry compressor is that which introduces no water into the air during compression4 ,wet compressors may be subdivided into two classes4 7#a7 ,those which inject water in the form of a spray into the cylinder during compression4 7#b7 ,those which use a water piston for forcing the air into confinement4 ,the injection of water into the cylinder is usually known as the ,colladon idea4 ,compressors built on this system have shown the highest isothermal results1 that is1 by means of a finely divided spray of cold water the heat of compression has been absorbed to a point where the compressed air has been discharged at a temperature nearly equal to that at which it was admitted to the cylinder4 ,the advantages of water injection during compression are as follows3 7#a7 ,low temperature of air during compression4 7#b7 ,increased volume of air per stroke1 due to filling of clearance spaces with water and to a cold air cylinder4 7#c7 ,low temperature of air immediately after compression1 thus condensing moisture in the air receiver4 7#d7 ,low temperature of cylinder and valves1 thus maintaining packing1 etc4 7#e7 ,economical results1 due to compression of moist air 7see table #c74 ,,table #c4--,,showing ,,the ,,relative ,,quantity ,,of ,,work ,,required ,,to ,,compress ,a ,,given ,,volume ,,and ,,weight ,,of ,,air1 ,,both ,,dry ,,and ,,moist--,,also ,,relative ,,volumes ,,with ,,and ,,without ,,increase ,,of ,,temperature ,,from ,,compression4 ,compression at ,compression a ,constant with ,temperature4 ,increase of ,mariotte's ,law4 ,temperature4 #aj4a #bj #fh #a4j #fh #bj4e #gaiiadfhj4fab #gicbafah #he4eahf #a4bbb #gccj4jibaaa #c4jbcejjbbejj #cj4cccaacefbcafj4deiaccfjbgbeacj4dbfg #a4cgebjjdj4aejace4ed4jcgjjjcejjj #dj4be #adbfjbijij4cgdaggcgcfahafe4fccj #a4diecdggj4aifaec4ed4hdhejjdejjj #ej4bjjafehjcchcj4cbjbabjidcbfaie4cchd #a4eiedfbij4bacafg #e4dehejjebejj #fj4afgahdgecgfhj4bhabdcajdieibbj4edbi #a4fhaehcej4bdjagi #f4jfgjjjfjjjj #gj4adcbjjchdjhgj4bebbgjdheeagbdc4bdgj #a4gehgjdjj4bfjaij #f4dgejjjffjjj #hj4abebadbbdcgjj4bbibieahfjbabfc4fejf4e a4hbhhjifj4bgd #ij4aaa #j4baj #bhb #eci4fa4hia #ajj4ajj #j4aie #bii #egj4ba4iej #a #b #c #d #e #f #g #h #i #aj #aa #ab #ac #ad #ae #af ,column ,heading #a ,tension in ,atmospheres4 #b ,volume4 #c ,work of ,compression4 ,cubic ,meters in ,kilogram-meters4 #d ,work of ,compression4 ,cubic ,feet in ,foot ,pounds4 #e ,volume4 #f ,work of ,compression4 7,dry47 ,cubic ,meters in ,kilogram-meters4 #g ,work of ,compression4 7,dry47 ,cubic ,feet in ,foot ,pounds4 ,deduced from #f4 #h ,temperatures4 7,dry47 ,cent4 #i ,temperatures4 7,dry47 ,fah4 #aj ,ratio of ,greater to ,less ,temperature4 ,absolute4 #aa ,loss of ,work in ,compressing one ,cubic ,meter in ,kilogram-meters4 ,by ,increase of ,temperature alone4 #ab ,percentage of ,work of ,compression ,converted into ,heat and ,lost4 ,by ,increase of ,temperature alone4 #ac ,final ,temperature if ,water is used in ,compression4 ,fah4 #ad ,percentage of ,water to ,air ,required4 #ae ,foot ,pounds to ,compress ,one ,pound ,air4 ,dry4 #af ,foot ,pounds to ,compress ,one ,pound ,air4 ,with sufficient ,moisture4 ,the first advantage is by far the most important one1 and is really the only excuse for water injection in air compressors4 ,we have seen 7table #c7 that the percentage of work of compression which is converted into heat and loss when no cooling system is used is as follows3 ,compressing to #b atmospheres loss #i4b per cent4 #c #ae4j #d #ai4f #e #ba4c #f #bd4j #g #bf4j #h #bg4d ,we see that in compressing air to five atmospheres1 which is the usual practice1 the heat loss is #ba4c per cent41 so that if we keep down the temperature of the air during compression to the isothermal line1 we save this loss4 ,the best practice in ,america has brought this heat loss down to #c4f per cent4 7old ,ingersoll ,injection ,air ,compressor71 while in ,europe the heat loss has been reduced to #a4f per cent4 ,steam-driven air compressors are usually run at a piston speed of about #cej feet per minute1 or from #fj-hj revolutions per minute of compressors of average sizes1 say #ah diameter of cylinder4 ,sixty revolutions per minute is equal to #abj strokes1 or two strokes per second4 ,an air cylinder #ah in diameter filled with free air once every half second1 and at each stroke compressing the air to #fj pounds1 and thereby producing #cji degrees of heat1 is thus1 by means of water injection1 cooled to an extent hardly possible with mere surface contact4 ,the specific heat of water being about four times that of air1 it readily takes up the heat of compression4 ,a properly designed spray system must not be confused with the numerous devices applied to air cylinders1 by means of which water is introduced4 ,in some cases the water is merely drawn in through the inlet valves4 ,in others it passes through the center of the piston and rod1 coming in contact with the interior walls of the air cylinder between the packing rings4 ,introducing water into the air cylinder in any other way1 except in the form of a spray1 has but little effect in cooling the air during compression4 ,on the contrary1 it is a most fallacious system1 because it introduces all the disadvantages of water injection without its isothermal influence4 ,water1 by mere surface contact with air1 takes up but little heat1 while the air1 having a chance to increase its temperature1 absorbs water through the affinity of air for moisture1 and thus carries over a volume of saturated hot air into the receiver and pipes1 which on cooling1 as it always does in transit to the mine1 deposits its moisture and gives trouble through water and freezing4 ,it is1 therefore1 of much importance to bear in mind that unless water can be introduced during compression to such an extent as to keep down the temperature of the air in the cylinder1 it had better not be introduced at all4 ,if too little water is introduced into an air cylinder during compression1 the result is warm1 moist air1 and if too much water is used1 it results in a surplus of power required to move a body of water which renders no useful service4 ,the following table deduced from ,zahner's formula gives the quantity of water which should be injected per cubic foot of air compressed in order to keep the temperature down to #ajd degrees ,fah4 ,weight of water ,weight of water to be injected at to be injected at ,heat units devel-#fh ,fah4 to keep #fh ,fah4 to keep ,compression oped in #a lb4 the temperature atthe temperature at by atmosphere free air by #ajd ,fah4 in lbs4 #ajd ,fah4 in lbs4 of above a volume4compression4 of water and per water for #a cubic lb4 of free air4 foot of free air4 #b #c4gjb #j4gcd #j4jef #c #e4hfg #a4ffd #j4jhi #d #g4djf #a4dfi #j4aac #e #h4eih #a4gja #j4aca #f #i4egj #a4hia #j4ade #g #aj4cih #b4jfc #j4aeh #h #aa4aji #b4bjd #j4afg #i #aa4gdj #b4cbi #j4agi #aj #ab4cja #b4ddj #j4ahh #aa #ab4hac #b4edb #j4aie #ab #ac4bgh #b4fcd #j4bjb #ac #ac4gjf #b4gai #j4bji #ad #ad4ajb #b4gih #j4bae #ae #ad4dga #b4hga #j4bbc ,objections to water injection are as follows3 7#a7 ,impurities in the water1 which1 through both mechanical and chemical action1 destroy exposed metallic surfaces4 7#b7 ,wear of cylinder1 piston and other parts1 due directly to the fact that water is a bad lubricant1 and as the density of water is greater than that of oil1 the latter floats on the water and has no chance to lubricate the moving parts4 7#c7 ,wet air arising from insufficient quantity of water and from inefficient means of ejection4 7#d7 ,mechanical complications connected with the water pump1 and the difficulties in the way of proportioning the volume of water and its temperature to the volume1 temperature and pressure of the air4 7#e7 ,loss of power required to overcome the inertia of the water4 7#f7 ,limitations to the speed of the compressor1 because of the liability to break the cylinder head joint by water confined in the clearance spaces4 7#g7 ,absorption of air by water4 ,before the introduction of condensing air receivers1 wet air resulting in freezing was considered the most serious obstacle to water injection2 but this difficulty no longer exists1 as experience has conclusively demonstrated that a large part of the moisture in compressed air may be abstracted in the air receiver4 ,even in the so-called dry compressors a great deal of moisture is carried over with the compressed air1 because the atmosphere is never free from moisture4 ,this subject will be referred to more fully when treating of the transmission of compressed air4 ,by far the most serious obstacle to water injection1 and that which condemns the wet compressor1 is the influence of the injected water upon the air cylinder and parts4 ,even when pure water is used1 the cylinders wear to such an extent as to produce leakage and to require reboring4 ,the limitation to the speed of a compressor is also an important objection4 ,the claim made by some that the injected water does not fill the clearance spaces1 but is aerated1 does not hold good1 except with an inefficient injection system4 ,the writer has increased the speed of an air compressor 7cylinders #ab in4 and #ab in4 by #ah in41 injection air cylinder7 ten revolutions per minute by placing his fingers over the orifice of the suction pipe of the water pump4 ,the boiler pressure remained the same1 the cut-off was not changed and the air pressure was uniform1 hence this increase of speed arose from the fact that the water was restricted and the clearance spaces were filled with compressed air1 which served as a cushion or spring4 ,while the volume of compressed air furnished by this compressor would be somewhat reduced by the restriction of the water1 yet the increase in speed which was obtained without any increase of power fully compensated for the clearance loss4 ,mr4 ,john ,darlington1 of ,england1 gives the following particulars of a modern air compressor of ,european type3 ,engine1 two vertical cylinders1 steam jacketed1 with ,meyer's expansion gear4 ,cylinders1 #af4i inches diameter1 stroke #ci4d inches2 compressor1 two cylinders1 diameter of piston1 #bc4j inches2 stroke #ci4d inches2 revolutions per minute1 #cj to #dj2 piston speed #ci to #eb inches per second1 capacity of cylinder per revolution1 #bj cubic feet3 diameter of valves1 viz41 four inlet and four outlet1 #e inches2 weight of each inlet valve1 #h lb42 outlet1 #aj lb42 pressure of air1 #d to #e atmospheres4 ,the diagrams taken of the engine and compressor show that the work expended in compressing one cubic meter of air to #d4ba effective atmospheres was #ch1abh lb4 ,according to ,boyle and ,mariotte's law it would be #cg1ecd lb41 the difference being #eid lb41 or a loss of #a4f per cent4 ,or if compressed without abstraction of heat1 the work expended would in that case have been #dh1aeh4 ,the volume of air compressed per revolution was #j4efed cubic meter4 ,for obtaining this measure of compressed air1 the work expended was #ba1eeg pounds4 ,the work done in the steam cylinders1 from indicator diagrams1 is shown to have been #be1bje pounds1 the useful effect being #he per cent4 of the power expended4 ,the temperature of air on entering the cylinder was #ej degrees ,fah41 on leaving #fb degrees ,fah41 or an increase of #ab degrees ,fah4 ,without the water jacket and water injection for cooling the temperature it would have been #cjb degrees ,fah4 ,the water injected into the cylinders per revolution was #j4ha gallon4 ,we have in the foregoing a remarkable isothermal result4 ,the heat of compression is so thoroughly absorbed that the thermal loss is only #a4f per cent42 but the loss by friction of the engine is #ad4e per cent41 and the net economy of the whole system is no greater than that of the best ,american dry compressor1 which loses about one-half the theoretical loss due to heat of compression1 but which makes up the difference by a low friction loss4 ,the wet compressor of the second class is the water piston compressor1 ,fig4 #ah4 ,illustration3 ,,fig4 #ah4--;,,hydraulic ,,air ,,compressor4 ,the illustration shows the general type of this compressor1 though it has been subject to much modification in different places4 ,in ,america1 a plunger is used instead of a piston1 and as it always moves in water the result is more satisfactory4 ,the piston1 or plunger1 moves horizontally in the lower part of a ,u shaped cylinder4 ,water at all times surrounds the piston1 and fills alternately the upper chambers4 ,the free air is admitted through a valve on the side of each column and is discharged through the top4 ,the movement of the piston causes the water to rise on one side and fall on the other4 ,as the water falls the space is occupied by free air1 which is compressed when the motion of the piston is reversed1 and the water column raised4 ,the discharge valve is so proportioned that some of the water is carried out after the air has been discharged4 ,hence there are no clearance losses4 ,this hydraulic compressor seems to have a certain charm about it1 which has resulted in its adoption in ,germany1 ,france and ,belgium1 and by one of the largest mines in the ,united ,states4 ,its advantages are purely theoretical1 and without certain adjuncts which have been in some cases applied to it1 even the theory is a very bad one4 ,the chief claim for this water piston compressor is that its piston is also its cooling device1 and that the heat of compression is absorbed by the water4 ,so much confidence seems to be placed in the isothermal features of this machine that usually no water jacket or spray pump is applied4 ,mr4 ,darlington1 who is one of the stanch defenders of this class of compressors1 has found it necessary to introduce spray jets of water immediately under the outlet valves1 the object of which is to absorb a larger amount of heat than would otherwise be effected by the simple contact of the air with the water-compressing column4 ,without such spray connections1 it is safe to say that this compressor has scarcely any cooling advantages at all1 so far as air cooling is concerned4 ,water is not a good conductor of heat4 ,in this case only one side of a large body of air is exposed to a water surface1 and as water is a bad conductor1 the result is that a thin film of water gets hot in the early stage of the stroke and little or no cooling takes place thereafter4 ,the compressed air is doubtless cooled before it gets even as far as the receiver1 because so much water is tumbled over into the pipes with it1 but to produce economical results the cooling should take place during compression4 ,water and cast iron have about the same relative capacity for heat at equal volumes4 ,in this water piston compressor we have only one cooling surface1 which soon gets hot1 while with a dry compressor1 with water jacketed cylinders and heads1 there are several cold metallic surfaces exposed on one side to the heat of compression1 and on the other to a moving body of cold water4 ,but the water piston fraternity promptly brings forward the question of speed4 ,they say that1 admitting that the cooling surfaces are equal1 we have in one case more time to absorb the heat than in the other4 ,this is true1 and here we come to an important class division in air compressing machinery--high speed and short stroke as against slow speed and long stroke4 ,hydraulic piston compressors are subject to the laws that govern piston pumps1 and are1 therefore1 limited to a piston speed of about #ajj feet per minute4 ,it is quite out of the question to run them at much higher speed than this without shock to the engine and fluctuations of air pressure due to agitation of the water piston4 ,the quantity of heat produced1 that is1 the degree of temperature reached1 depends entirely upon the conditions in the air itself1 as to density1 temperature and moisture1 and is entirely independent of speed4 ,we have seen that it is possible to lose #ba4c per cent4 of work when compressing air to five atmospheres without any cooling arrangements4 ,with the best compressors of the dry system one-half of this loss is saved by water jacket absorption1 so that we are left with about #aa per cent41 which the slow moving compressor seeks to erase4 ,we are quite safe in saying that the element of time alone in the stroke of an air compressor could not possibly effect a saving of more than half of this1 or #e per cent4 ,now1 in order to get this #e per cent4 saving1 we reduce the speed of an air-compressing engine from #cej feet per minute to #ajj feet per minute4 ,we must1 therefore1 in one case have a piston area three and one-half times that of the other in order to get the same capacity of air1 and in doing this we build an engine of enormous proportions with heavy moving parts4 ,we load it down with a large mass of water1 which it must move back and forth during its work1 and thus we produce a percentage of friction loss alone equal to twice or even three times the #e per cent4 heat loss which is responsible for all this expense in first cost and in maintenance1 but which really is not saved after all unless water injection in the form of spray also forms a part of the system4 ,it is obvious that cost of construction and maintenance have much to do with the commercial value of an air compressor4 ,the hydraulic piston machine not only costs a great deal more in proportion to the power it produces1 but it costs more to maintain it1 and it costs more to run it4 ,it is not an uncommon thing to hear engineers speak of the hydraulic piston compressor as the most economical machine for the purpose1 but that it is so expensive and takes up so much room1 and requires such expensive foundations that1 unless persons are willing to spend so much money1 they had better take the next best thing1 a high speed machine4 ,we hear of magnificent air-compressing engines1 the largest in the country1 and pilgrimages are made to see these artificial wonders when1 not unlike the old pyramids1 they represent a pile of inert matter--a monument to moneyed kings4 ,the hydraulic piston compressor has one solitary advantage1 and that is1 it has no dead spaces4 ,it was conceived at a time when dead spaces were very serious conditions--were positive specters6 ,valves and other mechanism connected with the cylinder of an air compressor were once of such crude construction that it was impossible to reduce the clearance spaces to a reasonable point1 and1 furthermore1 the valves were heavy and so complicated that anything like a high speed would either break them or wear them out rapidly1 or derange them so that leakages would occur4 ,but we have now reduced inlet and discharge valves and all other moving parts connected with an air cylinder to a point of extreme simplicity4 ,clearance space is in some cases destroyed altogether by what is1 as it were1 an elastic air head which is brought into direct contact with the piston4 ,all this reduces clearance to so small a point that it has no influence of any consequence4 ,the moving parts are made extremely simple1 even arriving at a point where inlet valves are opened and closed by their natural inertia4 ,mr4 ,sturgeon1 of ,england1 has applied a most ingenious and successful inlet valve1 which is opened and closed by the friction of the air piston rod through the gland4 ,we have1 therefore1 reached a point at which high speed is made possible4 ,long-stroke air compressors are evidently objectionable on the basis of greater expense of construction4 ,all the parts must be larger and heavier4 ,the fly wheels are increased enormously in diameter and weight1 and the strength of bearings must be enlarged in proportion4 ,it is difficult to equalize power and resistance in air compressors with long strokes4 ,the speed will be jerky1 and when slow1 the fly wheel rather retards than assists in the work of compression4 ,this action tends to derange the parts and makes large bearings a necessity4 ,the piston in a long-stroke compressor travels through considerable space before the pressure reaches a point where the discharge valve opens1 and after reaching that point it has to go on still further against a prolonged uniform resistance4 ,this makes rotative speed difficult4 ,during the early part of the stroke1 the energy of the steam piston must be stored up in the moving parts1 to be given out when the steam pressure has been reduced through an early cut-off4 ,with a short stroke and a large diameter of steam cylinder we are able to get steam economy or early cut-off and expansion without the complications of compounding4 99 99 99 99 99 ,continued from ,,supplement1 ,no4 #gic1 page #abfgg4 ,,the ,,power ,,of ,,water1 ,,or ,,hydraulics ,,simplified4 ,by ,g4,d4 ,hiscox4 ,,current ,,wheels ,,for ,,power ,,and ,,raising ,,water4 ,the natural flow of water in a current is probably one of the oldest and cheapest of the methods for obtaining power1 or the lifting of water within moderate elevations1 for a supply for irrigation and domestic purposes2 and we propose1 apart from the current wheel1 to treat only of self-water-raising devices in this chapter4 ,water wheels of various forms for this purpose have been used from time immemorial in ,europe1 ,asia and ,egypt1 where the record gives examples of wheels of the noria class from #cj to #ij feet in diameter2 the term noria having been applied to water wheels carrying buckets for raising water2 the ,spanish noria having buckets on an endless chain4 ,records of a ,chinese noria1 of #cj feet diameter1 made of bamboo1 show a lifting capacity of #cjj tons of water per day to a height of of the diameter of the wheel--velocity of current not stated4 ,for less quantity and greater elevation1 these forms of wheel may have pumps attached to the shaft1 by crank1 that will give a fair duty for a high water supply4 ,for power purposes1 as in the plain current wheel1 ,fig4 #bc1 there are two principal factors in the problem of power--the velocity of the current and the area of the buckets or blades4 ,illustration3 ,fig4 #bc ,their efficiency is very low1 from #be to #cf per cent41 according to their lightness of make and form of buckets4 ,a slightly curved plate iron bucket gives the highest efficiency1 thus 7 to the current1 and an additional value may also be given by slightly shrouding the ends of the buckets4 ,the relative velocity of the periphery of the wheel to the velocity of the current should be #ej per cent4 with curved blades for best effect4 ,the most useful and convenient sizes for power purposes are from #aj to #bj feet1 and from #b to #bj feet wide1 although1 as before stated1 there is scarcely a limit under #ajj feet diameter for special purposes4 ,in designing this class of wheels special attention should be given to the concentration and increase of the velocity of the current by wing dams or by the narrowing of shallow streams2 always bearing in mind that any increase in the velocity of the current is economy in increased power1 as well as in the size and cost of a wheel for a given power4 ,the blades in the smaller size wheels should be #a_/d of the radius in width1 and for the larger sizes up to #bj feet1 #a_/e to #a_/f of the radius in width and spaced equal to from #a_/d to #a_/c of the radius4 ,they should be completely submerged at the lowest point4 ,for obtaining the horse power of a current wheel1 the formula is ,area of #a blade velocity of the current in ft4 per sec4 ---------------------------------------- ------------------ #djj by the square of difference of velocities of current and wheel periphery the horse power2 or ,a ,v #b ------ 7,v - v7 h4 p4 #djj ,,tex3 frac,a times ,v#djj times 7,v - v7#b h4 p4 in which ,a equals the area of blade in square feet1 ,v and v velocities of current and wheel periphery respectively1 in feet per second4 ,thus1 for example1 a wheel #aj feet in diameter with blades #f feet long and #a foot in width1 running in a stream of #e feet per second--assuming the wheel to be giving as much power as will reduce its velocity to one half that of the stream--the figures will be #f' #e' #b ------- #b4e #j4dfh #djj ,,tex3 frac#f' times #e'djj times #b4eb #j4dfh horse power of the wheel4 ,the total power of the stream due to the area of the blade equals the ,square of the velocity of the stream ------------------------------------ ,twice gravity 7#fd4cc7 volume of water in cubic feet per second #fb4e 7weight of #a ,c'7 the value or gross effect in pounds falling #a foot per second4 ,this sum divided by #eej horse power4 ,thus1 as per last example1 #b #e ------ #cj #fb4e #fd4cc ---------------------- #a4cb the horse power of the current #eej ,,tex3 fracfrac#ebfd4cc times #cj times #fb4eeej #a4cb text the horse power of the current due to the area of the blades of the water wheel4 ,for the efficiency of this class of wheel1 with slightly curved and thin blades1 divide the horse power of the wheel by the horse power of the current area1 equals the percentage of efficiency4 ,as in the last case1 #j4dfh _/ #a4cb #j4ce per cent4 efficiency of the water wheel4 ,with higher velocities of stream and wheel the efficiency will be from #b to #c per cent4 less1 although the horse power will increase nearly with the increase in velocity of the current4 ,for details of application of various forms of current wheels for power purposes see illustrated description ,yagn's and ,roman's floating motors in ,,scientific ,,american ,,supplement1 ,no4 #dfc4 ,a very good example of a floating motor of the propeller class is ,nossian's fluviatile motor1 illustrated and described in ,,scientific ,,american ,,supplement1 ,no4 #fef4 ,illustration3 ,fig4 #bd4 ,fig4 #bd represents a very complete floating motor1 in which the floats are wedge shaped at the stem1 for the purpose of increasing the current between them1 the wheel being an ordinary current wheel1 as shown in ,fig4 #bc1 with a curved shield or gate in front1 which can be moved around the periphery of the wheel for the purpose of regulating its speed or stopping its motion by cutting off the stream from the buckets4 ,the float1 rising and falling with the stream1 is held in position by a braced frame swinging on anchorages within the mill on shore1 and parallel with a swiveled shaft4 ,tide wheels and tidal current wheels have been in use for more than #hjj years1 and were largely in use in ,europe and the ,united ,states during the first half of the present century4 ,no less than three were running in the immediate vicinity of ,new ,york1 in #ahdj1 for milling purposes4 ,their day seems to be past1 except in some special localities4 ,we will also pass them1 and illustrate some of the ,,self-,,acting ,,water-,,raising ,,devices4 ,the tympanum derives its name from its similarity to a drum as made by the ,romans1 but its origin was ,egyptian4 ,it is a current wheel with frame like ,fig4 #bc1 to the outside of which a set of chambers or tubes are fixed1 radiating spirally1 so as to lead the water to the shaft as the wheel revolves1 as shown in ,fig4 #be4 ,it has a lift of a little less than half its diameter1 and answers an excellent purpose for the irrigation of rice and cranberry fields1 or on streams running through low lands in arid districts4 ,it is still one of the ,nile irrigating wheels4 ,illustration3 ,fig4 #be ,the building of these wheels is within the scope of the carpenter and the tinsmith4 ,a short wooden shaft made square or octagonal1 as convenient1 with gudgeons in the ends and arms of wood bolted across each of the sides of the shaft1 or as shown in the cut1 will form a frame work upon which a rim may be fastened1 to which the blades and tubular buckets can be attached4 ,the directions in regard to the current wheel1 ,fig4 #bc1 may be followed as to number and form of blades1 which must be made in length and width proportional to the velocity of the stream and the quantity of water to be lifted by each tubular arm4 ,the tubes may be made of galvanized sheet iron and attached to the outside of the wheel1 as shown in ,fig4 #be4 ,,the ,,noria ,,or ,,bucket ,,wheel4 ,this is a simple current wheel with pot buckets1 rigid or swinging1 arranged on the rim of the wheel1 to carry up and discharge the water nearly at the top of the wheel1 and through the long ages that it has been in use for irrigation1 village water supply1 and even for private establishments1 has assumed a variety of forms in detail of construction ranging from the bamboo wheels of the ,chinese to the light iron wheels of modern construction4 ,we illustrate the most simple of these forms in ,figs4 #bf and #bg1 in which the first is a series of boxes or chambers in the rim of the wheel with side openings in the forward part of the box as the wheel revolves1 and a lip extending from the inner edge of the opening to direct the outflow into the trough4 ,illustration3 ,fig4 #bf4 ,another form1 ,fig4 #bg1 is arranged with swing buckets or pots1 pivoted just above their centers1 and with the catch trough so fixed as to tip the buckets at the highest point1 thus giving this wheel the greatest possible advantage as to height of discharge for a given diameter4 ,illustration3 ,fig4 #bg4 ,the power value of these wheels for raising water is a matter of computation as nearly reliable as for other devices for the same purpose1 when the velocity of the current is known at the point of contact with the blades4 ,the horse power of the wheel may be computed as for the current wheel1 ,fig4 #bc1 and1 as the horse power is equal to #cc1jjj pounds raised one foot high per minute1 we may assume a construction of wheel that will allow of discharging at #h feet above the stream2 then #cc1jjj _/ #h #d1abe pounds of water discharged at #h feet elevation per horse power per minute4 ,as the net power of the wheel in the last example1 for ,fig4 #bc1 was #j4dfh of a horse power1 then #d1abe #j4dfh #a1icj pounds of water raised #h ft4 per minute by the size of bucket and velocity of current in that case4 ,from this a deduction of #bj per cent4 should be made for loss by spill and imperfect construction1 so that #a1ejj pounds or #agf gallons per minute would be the probable output--over #bec1jjj gallons per day2 or1 for irrigating purposes1 equal to a rainfall of over #a inches in depth on #ej acres in one week4 ,the proportion of capacity of the lifting buckets for such a wheel becomes of as great importance as its efficiency4 ,if the buckets are too large1 the wheel will stall1 and if too small1 the wheel will not give its full duty4 ,for obtaining the approximate capacity of the lifting buckets1 assuming the example as above computed1 a #aj foot wheel with the velocity at periphery of #b feet per second is #aej feet per minute1 or five revolutions per minute1 nearly4 ,then #a1icj lb4 per m4 _/ #e revolutions #chf pounds water capacity for all of the buckets on the wheel4 ,if such a wheel is constructed with #af blades and #af buckets1 one between each blade1 then #chf _/ #af #bd pounds for each bucket1 or #ch _/ #ajj of a cubic foot4 ,the spill from this capacity of bucket being sufficient to compensate for the friction of the shaft journals4 ,the lifting buckets of the noria class1 ,figs4 #bf and #bg1 can be made of positive dimensions to suit the computations as above2 but those of the tympanum class1 ,fig4 #be1 should be made of dimensions to conform with the required capacity at the moment of leaving the water1 as the water at this point flows into the arm4 7,to be continued47 99 99 99 99 99 ,to remove paint and varnishes1 which resist the action of strong lye1 ,dr4 ,stockmeier recommends a mixture of water of ammonia1 two parts1 and turpentine1 one part2 this applied to the surface to be cleaned will1 after a few minutes' action1 enable the paint to be removed by use of cotton waste or similar material4--7,bayr4 ,gen4 ,ztg471 ,rundschau4 99 99 99 99 99 ,,on ,,gas ,,motors4 ,m4 ,witz1 says the ,gas ,world1 has been conducting a series of experiments on the ,delamare-,deboutteville and ,malindin gas engine1 driven by ,dowson gas1 and in which the gas generator takes the place of the ordinary steam boiler4 ,the engine was a one-cylinder motor in the establishment of ,messrs4 ,matter ,co41 ,rouen4 ,its power was #ajj horse indicated2 the cylinder was #bc inches in diameter1 the stroke #ch inches1 and the normal speed #ajj revolutions4 ,the engine is of the ,simplex type2 the kindling is electric2 the cycle of operations is fourfold1 with powerful compression4 ,the ,dowson generator is #cj inches inside diameter and #gf inches in height from the bars to the top4 ,air is blown in by steam driven in under the hearth4 ,there is a siphon1 a coke scrubber #aaj inches high1 a sawdust purifier1 and a gasholder of #gej cubic feet capacity1 and a pipe to the engine #e4b inches in diameter4 ,the total area occupied by this apparatus is #adj square yards1 of which two-thirds are built on4 ,the anthracite employed was from ,swansea1 containing #e4d per cent4 of ash4 ,the observations made with a string friction brake were continued for #fh hours1 everything used being carefully weighed and measured4 ,one day the machine was worked for #ae hours on end2 the other days it was worked with an interval of half an hour every #ab hours to clear the hearth1 poke the fire and lubricate the machine2 and it was clearly established that with a big enough generator it would be quite possible to work continuously for several days4 ,the following were the data for a day of #bd hours1 with an interval of half an hour3 #h3ee ,p4,m4 one day to #h3ee ,p4,m4 the next1 interval #h3cj to #i ,a4,m4 ,anthracite used1 #ah4d cwt42 coke used1 #c4db cwt42 water used for steam injection1 #bag4c gallons2 water used in scrubber1 #d1ajf gallons2 water used in cooling the cylinder1 #bj1jjj gallons2 oil used in cylinder1 #ad4hd pounds2 grease1 #a4h pounds2 revolutions of machine1 #adb1aeg1 or #ajj4h per minute2 effective work1 #ge4hf ,french horse power1 or #gg4d ,british2 gas used1 #f1gdb cubic feet per hour1 at #ggb mm4 pressure and #gj4g ,f41 or #hc4g cubic feet per effective horse power2 efficiency1 #fi per cent4 ,now1 with regard to the comparison between the large gas motors and steam engines of the same size1 ,m4 ,witz goes on to remark that the gas engine is by no means1 as was formerly thought on high authority1 necessarily restricted to the domain of smaller work and sizes4 ,even in early times it was seen that the gas engine belonged to a type in which there were possibilities of improvement greater than those available in the steam engine1 because the difference of temperature between the working substance in its hotter and its cooler condition was greater than in the steam engine2 and consumptions of #e1bej cubic feet per horse power per hour soon descended step by step as far as #b1jfj1 while the power went up1 past #d1 #h and #ab1 to #be or #ej horse power2 and in the exhibition of #ahhi there were gas engines seen in which the explosion chamber had a diameter of as much as #bc inches4 ,but the price of coal gas seemed to be too high for use in these large engines1 in which sizes steam is comparatively cheap2 and so poorer gas1 which1 though possessing only about #bh per cent4 of the heating power1 is still cheaper in proportion than coal gas1 when it is made on the spot1 was introduced to tide over the difficulty4 ,difficulties have been successively overcome1 with the result which we have just seen1 namely1 #a4cg pounds of anthracite per effective horse power1 or about half the carbon which a steam engine of the same power of excellent design1 and well kept up1 would consume4 ,a #ej horse simplex at ,marseilles1 in ,barataud's flour mill1 is said to have run for the last #b years on #a4ab pounds of ,english anthracite per effective horse power2 and thus ,m4 ,witz says his predictions of #aj years ago1 that the gas producer would some day replace the boiler1 are being verified in such a way as to surprise even himself4 ,but the objection is stated1 and it is a serious one3 the weight of fuel is not the only thing to be considered4 ,the steam engine uses coal1 the producer requires ,english anthracite1 which is dearer2 the gas motor uses a great deal of water and a great deal of oil1 which cost money2 and gas motors are dear1 while gas producers and their adjuncts cost a tidy bit of money1 and wear out pretty fast4 ,is not steam1 after all1 more economical in the long run8 ,besides1 producers are bulky and take up a great deal of space2 the weight of fuel is only one element in a complicated problem4 ,in order to study the grounds of this objection1 ,m4 ,witz has instituted a comparison between the actual cost of large steam engines and that of gas motors of similar size4 ,take a good ,galloway or multitubular boiler2 for #ge horse power effective the heating surface must be at least #gd square feet4 ,using good ,cardiff coal1 with #d per cent4 of ash1 and a heating power of #ae1ffj ,fahr4 units2 the steam raised will be #h to #i pounds per pound of coal1 so that #i1djj to #aj1egg ,fahr4 units are utilized in raising steam1 or #fh to #gf per cent41 which is an excellent result4 ,take an engine of #af inch cylinder diameter1 #dj inch stroke1 and #ff revolutions1 etc42 it will use #bb4d pounds of steam per horse power effective1 which represents #b4dg to #b4h pounds of coal under the boiler4 ,these #aj pounds of steam carry #aa1geb ,fahr4 units of heat1 and produce work equal to #ge horse1 or #a1adc ,fahr4 units of heat2 which corresponds to an efficiency of #i4g per cent4 ,in a gas motor1 on the other hand1 we find the materials employed1 as per the above data1 to contain #h1ieh ,fahr4 units of heat1 and to make gaseous fuel in which #f1cdc units are available2 a return of #gj4f per cent1 in the producer4 ,the motor receives these #f1cdc1 and converts #a1adc of them into work2 an efficiency of #ah per cent4 ,in order to be equivalent from the heat point of view1 a steam engine ought to produce a horse power effective per #i4gb pounds of steam at #e atmospheres2 but no such steam engine exists4 ,m4 ,witz goes on with comparative estimates4 ,for a ,corliss engine and boiler1 with chimney1 etc41 complete1 and putting these up1 he allows #a1bhj2 for a ,simplex gas motor and ,dowson producer complete1 including putting up1 he allows #a1bij1 which he explains to be average actual prices2 but these prices do not cover cost of transport1 and ,m4 ,witz does not go into cost of masonry for buildings1 apart from foundations1 etc41 for the apparatus and machinery4 ,as to water1 the gas motor takes #bae cubic feet per horse power effective4 ,a condensing steam engine uses five times as much4 ,the lubricating oil used at ,rouen was a mixture of ,russian oil at #dcj fr4 per ton1 and ,ferry and ,heduit ,f4,h4 oil at #ijj fr42 the average was #fej fr4 per ton1 or #b4h;d4 per pound4 ,wanner grease1 at #f4d;d4 per pound1 was used for the moving parts4 ,a steam engine requires less oil for the cylinder1 but the same quantity for the moving parts4 ,the attendance on the gas motor is too much for one man1 not enough to occupy two2 reckon it at #ds4 #i;d4 a day4 ,these elements enable us to calculate the daily cost of the gas motor1 of #ge actual horse power1 in comparison with a steam engine of the same size4 ,steam ,engine4 s4 d4 ,upkeep1 interest and sinking fund at #ae per cent1 on #a1bib #aic4h per day4 #ab #aa ,cardiff coal1 #b4fdc pounds per actual horse power per hour2 #b4fdc #aj #ge in #aj hours #a1ihb pounds coal at #bbs4 a ton4 #ai #e ,oil1 #c4cf pounds per day at #b4h;d4 per pound4 #j #i ,grease1 #j4fg pound at #f4d;d4 #j #d ,wages4 #d #i --------- #a #ah #d ,gas ,engine4 s4 d4 ,upkeep1 interest and sinking fund at #ae per cent4 on #a1bib is1 per day4 #ab #aa ,anthracite1 #a4aef pound per actual horse power per hour for #gej horse-hours1 at #bes4 #f;d4 #i #aj ,coke1 #j4bae pound #aj #ge #afa pounds at #bhs4 #b #j ,oil1 #j4jjhd pound per actual horse power per hour1 or #j4jjhd #aj #ge #f4bh pounds at #b4h;d4 #a #e ,grease1 #j4ged pound per day at #f4d;d4 #j #e ,electric kindling1 on cost4 #j #c ,wages4 #d #i --------- #a #aa #h ,the big gas engine making its own poor gas1 and running #aj hours a day1 has thus the best of it in the comparison with the steam engine of equal power4 99 99 99 99 99 ,a ,,projecting ,,apparatus ,,for ,,balances ,,of ,,precision4 ,the luminous projection apparatus illustrated herewith1 when adapted to a balance of precision1 permits of effecting weighings very rapidly4 ,for the same approximation1 the velocity of oscillation becomes five or six times greater1 and1 by the method employed1 the last centigrammes and the milligrammes and their fractions are estimated directly1 with immediate verification4 ,as the apparatus is independent of the parts of the balance1 it can be placed on all the existing laboratory balances of precision4 ,illustration3 ,,projecting ,,apparatus ,,for ,,balances ,,of ,,precision4 ,the modification introduced into the balance consists in the displacing of the center of gravity of the beam in such a way as to diminish the sensitiveness1 and consequently to obtain a much greater velocity1 and then1 by optical means1 to considerably increase the amplitude of the oscillations4 ,instead of the oscillations being observed through the microscope1 they are projected upon a divided screen forming a dial1 the division of which is seen by transmitted light4 ,the apparatus consists of a small achromatic objective placed at the extremity of the tube of a microscope1 in which there is a divided screen that receives the enlarged image of the reticule fixed upon the needle4 ,upon this reticule are projected the rays 7condensed by a powerful lens7 that come from a luminous source placed behind the balance4 ,the focusing is done by means of a rack and pinion4 ,the luminous source employed is a gas burner with reflector4 ,this is placed in a walnut box in order to prevent any projection of heat upon the balance4 ,this burner1 thus isolated1 is lighted for but one or two minutes at a maximum1 at the end of each weighing4 ,so1 on fixing a thermometer in the cage1 we find that no variation1 ever so slight1 occurs in the temperature4 ,in order to effect a weighing1 the gas being turned down to a taper1 we proceed as with an ordinary balance until the extremity of the needle no longer emerges from the lower dial4 ,then we count the difference of the number of the divisions made by the needle to the right and left of zero4 ,this difference1 multiplied by the approximate value1 in milligrammes1 of each division of this dial 7value given by the instrument7 immediately gives the number of centigrammes and milligrammes that must be added to the weights already placed upon the pan of the balance in order to obtain an equilibrium1 to about a half division of the lower dial4 ,the value of each division of this dial varies from #c to #aj milligrammes according as the balance shows #j4a or #j4e milligramme4 ,as the dial has #aj divisions on each side of the central mark1 we thus estimate1 without tentatives1 the three last centigrammes or the last decigramme1 according to the sensitiveness4 ,at this moment the doors of the cage are closed1 in order to prevent draughts of air1 the gas is turned on by means of a regulating cock1 and the balance is manipulated by first lowering the beam and then bringing the pans to a standstill4 ,we then read the difference of the divisions traversed to the left and right upon the luminous dial through the image of the reticule4 ,the images are reversed upon the dial1 but practice soon causes this petty difficulty to disappear4 ,this number of divisions indicates the number of milligrammes and fractions of a milligramme by which it is necessary to shift the counterpoise on its arm in order to obtain a perfect equilibrium1 which latter is verified by a simple reading4 ,every half division of the dial corresponds1 as to weight1 to the sensitiveness indicated for the instrument4 ,with a little practice a weighing effected as above described takes but a quarter or a fifth of the time that it does with an ordinary balance4--,revue ,industrielle4 99 99 99 99 99 ,,starches ,,for ,,the ,,finishing ,,of ,,cotton ,,fabrics4 ,the starches have been classified by ,dr4 ,muter1 according to the appearance they give under the microscope1 into five groups3 ,class ,i4--,hilum and concentric rings visible4 ,all the granules1 oval or ovate4 ,tous-le-mois1 potato1 arrowroot1 etc4 ,class ,,ii4--,the concentric rings are all but invisible1 the hilum is stellate4 ,maize1 pea1 bean1 etc4 ,class ,,iii4--,the concentric rings are all but invisible1 also the hilum in the majority of granules4 ,wheat1 barley1 rye1 chestnut1 etc4 ,class ,,iv4--,all the granules truncated at one end4 ,sago1 tapioca1 etc4 ,class ,v4--,all the granules angular in form4 ,rice1 tacca1 arrowroot1 oats1 etc4 ,the principal starches used for finishing cotton fabrics are potato 7farina71 wheat1 ,indian corn 7maize71 rice1 tapioca1 arrowroot1 sago2 the last three not so often as those previously named4 ,illustration3 ,,potato ,,starch4 ,illustration3 ,,arrowroot ,,starch4 ,illustration3 ,,wheat ,,starch ,illustration3 ,,rice ,,starch ,illustration3 ,,sago ,,starch ,illustration3 ,,indian ,,corn ,,starch ,illustration3 ,,tapioca ,,starch 99 99 99 99 99 ,,marble ,,and ,,mosaic4 ,footnote3 ,a paper recently read before the ,architectural ,association1 ,london4--,from the ,architect4 ,by ,t4,r4 ,,spence4 ,i do not propose to enter into any historical details as to the first and subsequent application of mosaics4 ,in a general sense we understand mosaic as a combination of various more or less imperishable materials--fixed together by cement or other adhesive substances--and laid over walls1 floors1 etc41 with a view to permanent decorative effect4 ,the substance of the tesser is of many kinds1 namely1 glass1 cheap and precious marbles1 hard stone1 and burnt clay1 these mentioned being mainly in use for architectural purposes4 ,for decorative schemes we collect as many gradations of color as are obtainable in such durable materials in their natural or manufactured state1 and thus form a color palette which we regard in the same sense as a painter would his pigments4 ,of course1 the first proceeding is to prepare a design on a small scale1 which shall embrace your notions of color only4 ,then follows a full-sized cartoon1 which ,i need hardly add shall embrace your best efforts in drawing4 ,a tracing is made of the latter and transferred to sheets of cardboard4 ,this cardboard is cut to the size of certain sections of your design1 and1 for convenience1 should not be more than1 say1 #bj in4 square4 ,of course1 it will not always be square1 but will bear the same relation to your complete cartoon as a map of the counties would to that of all ,england4 ,now1 working from the small design 7of color71 the tesser are cut to the forms required1 laid face downward1 and glued on to the cardboard sections containing your enlarged cartoon4 ,when the design is all worked out on these sections they are ready for fixing on walls or floor by laying them home on a float of cement4 ,when the cement sets1 the cardboard sticking to the face is washed off1 and the joints of tesser flushed over with cement and cleaned off1 leaving all joints filled up level4 ,there are other processes used for the same end4 ,the technical processes need not occupy our attention at present4 ,there is one process that may appeal to you1 and that is executing the work in situ by floating on a limited expanse of cement1 and sticking on the tesser at once4 ,it has the advantage of enabling the artist or architect to see the effect of his efforts under the fixed conditions of light and height4 ,i shall confine myself to vitreous or glass mosaic1 which for durability1 extended scales of primary colors and their numerous semi-transparent gradations is unequaled by any substance yet used for wall or floor decoration4 ,i am surprised1 having all these fine qualities1 it is not more used by architects4 ,if you require proofs of its triumphs1 go to ,st4 ,mark's1 of ,venice1 and stand under its mellow golden roof4 ,there you will find its domes and vaulted aisles1 nave and transepts entirely overlaid with gold mosaic1 into which ground is worked--in the deepest and richest colors and their gradations that contemporary manufacturers could produce--subjects selected from the creation down to the life of ,christ1 in addition containing a complete alphabet of early ,christian symbolism4 ,the roof surfaces being one succession of over-arching curves become receptive of innumerable waves of light and broad unities of soft shadows1 giving the whole an incomparable quality of tone and low juicy color4 ,never use your gold but on curved or undulating surfaces4 ,flat planes of gold only give the effect of a monotonous metallic yellow1 and can never be beautiful1 owing to the absence of the variations that come with waves of shadow4 ,by letting out the reins of imagination we might feel that in this a tenth century ,giorgione has given off the mental impressions of all the golden autumn of his life4 ,his material gave him an advantage over his great followers of the fifteenth and sixteenth centuries1 insomuch that glass has a living and glowing quality of light not existing in the somewhat clouded purity of oil or fresco4 ,in ,st4 ,mark's we have an example of the superb treatment in deepest and most ,titianesque scales applied to curved forms1 but to find a similarly complete example of the use of lighter tones and on flat surfaces1 we must turn to ,ravenna4 ,i can give you no adequate description of the wall mosaics of ,ravenna4 ,in the sense of delicate color they remind me of some of the subtile harmonies of many of the finest works of the modern ,french school--of the ,impressionists and others who combine that quality with a true instinct for design4 ,in standing before them you feel that the ,dagnan ,bouverets1 the ,mersons1 the ,cazins1 the ,puvis de ,chavannes1 etc41 of the fifth century have had a hand in the conception and realization of the beautiful compositions to be found on the nave walls of the two churches of ,st4 ,appollinare ,nuovo and ,st4 ,appollinare in ,classe4 ,here all the scales are of delicate degrees of light tones1 supreme in their beauty1 completeness1 and1 most important to us1 their true decorative instinct4 ,in the ,baptistery we find what ,i may term a third essay in color1 by weaving in rich1 dark1 and glowing colors on figures and bold sinuous forms of ornament in such a skillful and judicious manner that the whole dome seems to be alive with harmonies1 although they are mostly primaries4 ,as you know1 rules for the disposition of color are futile1 yet some details that struck me as eminently satisfactory may interest you4 ,in all cases the tesser are of small dimensions1 about a quarter of an inch square4 ,the stucco joints are large and open1 surfaces far from level1 but undulating considerably4 ,the tesser stick up in parts1 brilliant edges showing4 ,absence of flatness gives play to the light4 ,the gray of the stucco joints brings the whole composition together1 serving as cool grays in a picture to give tender unity4 ,gold1 apart from backgrounds and large surfaces1 is used very cleverly in small pieces in borders of garments1 and more especially in thin outlines to make out the drawing and certain flowing forms of ornament4 ,brilliant pieces of glass actually moulded at the kiln into forms of jewels add brilliancy to crowns1 borders1 etc4 ,these stick boldly out from the surface4 ,i noticed in the ,baptistery below the springing of the dome a frieze about #b ft4 #f in4 deep1 having the ground entirely in black1 through which was woven in thin gold lines a delicate foliated design4 ,this1 in conjunction with the upper surfaces in dark1 rich color1 had a most delightful effect4 ,we1 as students1 can learn most from the ,ravenna examples1 for great are the needs of light and silvery color in this country1 where gray and gloomy days far outnumber those in which the sun gives liberally of his light4 ,i may say1 in passing1 as our subject is really a matter of decoration1 that our nineteenth century efforts in this direction are all of a somewhat gloomy tendency4 ,we fill our rooms with imitations of somber ,spanish leather1 stain and paint our woodwork in leathery and muddy tones1 to arrive at what is now a sort of decorator's god4 ,quaintness is the name of that god4 ,many are the sins for which he has to answer4 ,had we not better worship a deity called beauty1 whose place is a little higher up ,parnassus8 ,why should we not in our endeavors attempt in some measure to transfix the brilliant harmonies that follow the sun in his liberal and gracious course8 ,this muddy quaintness is certainly pleasant for brief periods1 when lamps are low and fire light gilds and deepens its parts4 ,turn the sunlight on these so-called triumphs of the modern decorator's art1 and then you feel the lack of many a phase of color that might have been borrowed from the thousand and one examples that in nature he vivifies and makes brilliant4 ,referring again to the ,ravenna mosaics1 ,i can only add that at the present day an extended palette of colored glass is available4 ,the technical difficulties are not great1 and there is no question as to the fine qualities of design and color that are to be obtained in this material4 ,the great point in this1 as in all other schemes of decoration1 is the art1 the mental quality of conception1 and the sense of color and fitness4 ,if we hold the precious heritage of an artist's mind--that divine and rare something which gives form1 color1 and completeness to a story1 a dream or a vision--then very little difficulty follows in making vitreous mosaic a valued servant in the realization of a fine creation4 ,it is the function of architects to design suitable spaces for color decoration1 so bound in by dignified mouldings and other details of his constructive art1 in such a manner that the addition of decorative color shall in no way mar the scheme of his complete work1 but shall 7under these well ordered distributions7 have set on them the seal and crown of color which is inseparable from a perfect piece of architecture4 ,in such spaces he may dream his dreams1 tell his stories1 and stamp on them for centuries his subtilest and divinest thoughts4 ,may ,i not urge that to such spaces must be given the best that is in you8 for once placed so shall they remain unchanged through generations1 time being powerless to add any mellow garment of tone or softening quality whatever4 ,i mistook the title of the subject in thinking that it was mosaic only1 and at the last moment found it was marble and mosaic4 ,however1 the same dominant principles shall underlie the treatment of marble4 ,it is a question of the finer instincts for form and color4 ,in recent years the demand for choice decorative materials has been the means of opening out many marble quarries all over the world4 ,transit being easy1 a large scale of varieties is available4 ,one fine addition is the ,mexican onyx4 ,my feeling is that the most beautiful marbles are those where the soft and sinuous veins melt and die into the general body1 comparatively sharp markings dying right away at the edges into innumerable gradations4 ,marbles having strong and hardly marked veins present great difficulties in distribution4 ,if they are near1 they offend you with their coarseness2 and1 placed at a distance1 the hard vein lines have very little decorative value4 ,i should say use these in narrow slips1 with very little moulded profile or as parts of intazzio4 ,mouldings should be specially designed for different marbles4 ,i should say mainly on the principle of sudden contrasts2 that is1 large members with very little curve bound with members very small in detail1 thus obtaining sharp lines1 having little surface to be influenced or distorted by the veined markings1 and serving to sharpen up and give form to the broader members 7which show the color qualities of the marble71 much as you sharpen up an ink drawing by underlining4 ,these small members serve the architect's purpose for the expression of vertical and horizontal lines1 and where decisive and cutting shadows are required in the composition of his work4 ,if delicate carving forms part of your design1 ,i should say statuary is the best1 as you have no veins to distort your detail4 ,i need hardly add that economy should be studied in using precious marbles1 without injuring the durability of the work4 ,contours may be built up in thin sections4 ,intazzio is a beautiful form of treating marble on an inexpensive ground4 ,gem-like effects may be obtained by inlaying with smaller pieces1 following such ornamental forms as your inventive brains shall dictate4 ,perhaps the pockets of your clients will be the chief dictator4 ,heraldic emblazonings1 inlaid in marble1 are highly effective4 ,the conditions of the heraldry necessitate the use of many varieties1 but in such small quantities that on a large simple field they are rarely out of harmony4 ,in addition they map out a large and interesting variety that will save the worry of creation of designs coming entirely from your own brain1 and you know the worry of an architect's life makes him hail with pleasure at times a rest from the strain of creation4 ,this heraldic work may be seen to perfection in the chapel of the tombs of the ,medici at ,florence4 ,at the ,pitti ,palace are some tables which you may know where marble intazzio can no further go4 ,alabaster does not appeal to me1 it is somewhat sugary in results4 ,if you are fortunate enough to have a sculptor who is a sort of nineteenth century ,donatello1 let him work his will on statuary or such restful marble4 ,the celebrated monument in the church of ,s4 ,giovanni ,paulo1 at ,venice1 which ,ruskin says is the finest monument in the world1 if my recollection serves me correctly1 is in white marble1 and its beauty comes entirely from the sculptor's art4 ,such monuments give you much better than any words of mine ample suggestions for marble treatment4 ,i may quote such names as ,nicolo ,pisano and ,verocchio4 ,photos of some of their work ,i have brought4 ,note ,pisano's beautiful white altar at ,bologna1 and ,mina de ,fiesole's work in ,florence4 ,they all show the sculptor as supreme4 ,why should not we encourage individual young sculptors more8 ,give them portions of your work in which they can put all the fervor and enthusiasm of young manhood4 ,their powers may not be ripe1 but they possess a verve and intensity that may have forever fled when in later years the imagination is less enthusiastic and the pulses slower4 ,i am sure there are many young sculptors now wanting commissions who have been trained at the academy1 and better still1 in the best ,french schools4 ,i maintain that the contemporary ,french school of sculpture is in its line equal to any school of sculpture that has ever existed1 not excepting that of ,phidias or that of the ,italian ,renaissance of the fifteenth and sixteenth centuries4 ,i believe history will confirm this4 ,why not give these men an opportunity1 and help on the movement to found a truly ,english school of sculpture1 rather than give all such work to trading firms of carvers1 who will do you any number of superficial feet1 properly priced and scheduled1 and in the bills of quantities1 of any style you please1 from prehistoric to ,victorian ,gothic8 ,of course1 this is our ,british way of founding a great school4 ,there is one method of treatment that appeals to me very strongly1 and that is the application of colored metals to marble1 more especially bronze and copper4 ,i may quote as a successful example near the ,wellington ,memorial at ,st4 ,paul's4 ,another suggestion--although it is not used in combination with marble1 but it nevertheless suggests what might be done in the way of bronze panels--that is1 the ,fawcett ,memorial1 by ,gilbert1 in the west chapel at ,westminster ,abbey4 99 99 99 99 99 ,,the ,,st4 ,,lawrence ,,hospital ,,for ,,the ,,insane4 ,the ,st4 ,lawrence ,state ,hospital at ,ogdensburg1 ,n4,y41 is a center of public1 professional1 philanthropic1 and legislative interest4 ,though projected in advance of the adoption of the system of ,state care for the insane1 it was opened at a time to make it come under close observation in relation to the question of ,state care1 and the friends of this departure from the inefficient1 often almost barbarous provisions of county house confinement could have no better example to point the excellence of their theories than this new and progressively planned ,state hospital4 ,the members of the ,state ,lunacy ,commission and ,miss ,schuyler and her colleagues of the ,state ,charities ,aid ,society1 who fought the ,state care bills through the ,legislature this winter and in #ahij1 would be repaid for all of their trouble by contrasting the condition of the inmates of the ,st4 ,lawrence ,state ,hospital with the state they were in under their former custodians1 the county officers of the northern ,new ,york counties4 ,at the best1 even when these officials realized the responsibility of their charge and were actuated by humane impulses1 the county houses offered no chance of remedial treatment4 ,custody and maintenance1 the former mainly a reliance on force1 the later often of scant provision1 were the sum total of what was deemed necessary for the lunatics4 ,in their new environment they find everything as different in accommodations and treatment as the word hospital in the title of the institution is different in sound and significance from the hope-dispelling1 soul-chilling names of asylum1 mad house1 and bedlam formerly given to all retreats for the mentally afflicted4 ,they find1 and it is an encouraging feature of the plan that so many of them quickly see and appreciate it1 that they are considered as sufferers from disease and not from demoniacal possession4 ,the remarkable range of classification provided for1 the adaptability of construction to the different classifications1 the reliance on occupation1 the dependence on treatment1 and the subordination of the custodial feature1 except where a wise conservatism demands its retention1 are apparent alike to inmates and visitors4 ,this hospital is complete as to plans1 and as to the power plant1 drainage1 and subway construction necessary for the #a1ejj patients1 that the legislature has provided for in its law establishing the institution4 ,buildings are already finished and occupied that accommodate #bjj inmates1 and the contractors have nearly finished part of the central group that will bring that number up to nearly #a1cjj4 ,the appropriation asked for this year by the managers will be scaled down considerably by ,mr4 ,mc,clelland1 the very economical chairman of the ,ways and ,means ,committee of the ,democratic ,assembly4 ,but1 unless he has miscalculated1 there will be money enough to carry on the work of construction to advantage for the year4 ,an appropriation sufficient to complete the buildings at once was thought by many to be the wisest economy1 but big figures in an appropriation bill have very little chance this year4 ,the bill establishing the ,state ,hospital district and providing for the building of the institution fixed the per capita cost of construction1 including the purchase of land1 at #a1aej1 and the plans have been made on that basis for #a1ejj patients4 ,but if the needs of the district should require it1 the capacity could be increased by an almost indefinite extension of the system of outlying colony groups at a very small per capita cost1 as the central group is by far the most expensive in construction4 ,the administration group in part1 and one outlying group1 with the general kitchen1 bakery1 workshop1 laundry1 employes' dwelling house1 power house1 and pumping station1 are already erected1 and have added a feature of architectural beauty to ,point ,airy4 ,this point1 of itself of picturesque and romantic beauty1 juts into the ,st4 ,lawrence ,river at the head of the ,galoup ,rapids1 three miles below ,ogdensburg4 ,it is a part of the hospital farm of #iej acres1 which includes woodland1 meadow1 farm land1 and a market garden tract of the #ajj an acre grade4 ,the location of the institution in these particulars and in reference to salubrity1 sewerage facilities and abundance and excellence of water supply1 is wonderfully advantageous4 ,in planning the hospital ,dr4 ,p4,m4 ,wise1 who has since become its medical superintendent1 aimed to take the utmost advantage of the scenic and hygienic capabilities of the site1 and to improve on all previous combinations of the two general divisions of a mixed asylum--a hospital department for the concentration of professional treatment1 and a maintenance department for the separate care of the chronic insane4 ,he was anxious to secure as much as possible of the compactness and ease of administration of the linear plan of construction1 with wings on either side of the executive building of long corridors occupied as day rooms1 with sleeping rooms opening out of them on both sides4 ,but he wanted to avoid the depressing influence of this monotonous structure1 as the better results of variety and increased opportunities of subdivision and classification are well recognized4 ,he was not1 however1 prepared to accept wholly that abrupt departure from the linear plan known as the cottage plan1 which in some institutions has been carried to the extreme of erecting a detached building for every ward4 ,the climate of ,st4 ,lawrence county forbade this4 ,her winters are as vigorous as those of her ,canadian neighbors1 even as her people are almost as ebullient in their politics as the vigorous warring liberals and conservatives across the river4 ,and there are features of the linear plan that can only be left out of our asylum structure at the expense of efficiency4 ,other rules that he formulated from his experience were that a building for the insane should never exceed two stories in height2 that fire proof construction and at least two stairways from the upper floors should be provided2 that day rooms should be on the first and sleeping rooms on the second floor2 that all buildings for the insane who suffer from sluggish and enfeebled circulation of the blood should be capable of being warmed to #gj in the coldest weather2 that ample cubic space and ventilation should be provided2 and that1 as far as possible1 without too great increase of the cost of maintenance or sacrificing essential provisions for treatment and necessary restraint1 asylums should aim to reproduce the conditions of domestic life4 ,illustration3 ,,the ,,st4 ,,lawrence ,,hospital ,,for ,,the ,,insane4 ,state ,architect ,isaac ,g4 ,perry planned the ,st4 ,lawrence ,state ,hospital buildings on ideas suggested by medical experience1 with a breadth of comprehension and a technical skill in combining adaptability1 utility1 and beauty that have accomplished wonders4 ,the buildings are satisfactory in every particular to every one who has seen them1 and even the most casual observer is impressed with the effect of beauty4 ,this was accomplished without elaboration of material1 expressive carving or finish4 ,the ornamentation is purely structural and is obtained by a handling of the materials of construction which also yielded the largest promise of strength and durability4 ,the central hospital group1 of which an idea is given in the cut1 now consists of five buildings4 ,the picture shows three1 the center one and two of the flanking cottages on one side4 ,they are matched on the other side4 ,the central or administration building is a three story structure of ,gouverneur marble1 and1 like all of the stone used1 a native ,st4 ,lawrence county stone4 ,the marble's bluish gray is relieved by sparkling crystallizations1 and its unwrought blocks are handled with an ornamental effect in the piers1 lintels1 and arches1 and well set off by a simple high-pitched slate roof1 with terra-cotta hiprolls1 crestings1 and finials4 ,the open porches are both ornamental and useful1 taking the place of piazzas4 ,the tower is embellished with a terra-cotta frieze4 ,all accommodations for an executive staff for the #a1ejj patients may be provided in this building4 ,behind it on the south is a one story building whose ground plan is the segment of a circle4 ,it contains sun rooms1 medical offices1 general library1 laboratory and dispensary1 and the corridor connecting the reception cottages1 one for women1 on one side1 and one for men on the other1 with the administration building4 ,as this one story structure is #aga feet by #da1 the buildings known as cottages of the central group are more than nominally separated4 ,all the advantages of segregation and congregation are combined4 ,the reception cottages are of pale red ,potsdam sandstone4 ,their simple construction is pleasing4 ,the ground plan is in the form of a cross2 the angles of the projections being flanked by heavy piers between which are recessed circular bays carried up to the attic and arched over in the gables4 ,the cross plan affords abundant light to all the rooms1 and as much of the irregular outline as possible is utilized with piazzas4 ,with still another recourse to the combination corridor plan1 the observation cottages are joined to the reception cottages on each side4 ,the other utilization of the corridor in this case is for conservatories4 ,the observation cottages are irregular in plan and vary from each other and from the other buildings in the group4 ,unwrought native bluestone is the building material4 ,these cottages contain a preponderance of single rooms1 the purpose being to keep patients separate until their classification is decided upon4 ,the buildings planned but not yet constructed of the central group include two cottages for convalescents and two one-story retreats for noisy and disturbed patients4 ,in both cases the plans are the most complete and progressive ever made4 ,in the first the degree of construction is reduced to the minimum4 ,convalescents are to have freedom from the irritations of hospital life that often retard recovery4 ,great reliance is placed upon that important element in treatment1 the rousing of a hopeful feeling in the mind of the patient4 ,the retreat wards1 with accommodations in each wing for eighteen patients1 show in this particular how little the old method of strict confinement is to be employed in the new institution4 ,that proportion of the total insane population of #a1ejj is regarded as all that it is necessary to sequester to prevent the disturbance of the rest4 ,hollow walls1 sleeping room windows opening into small areas1 and corridor space between the several divisions are features which make the per capita cost of the construction comparatively large for these two cottages1 but which1 it is believed1 will prove to be wise ones4 ,all of these buildings are as complete from a hospital standpoint as can possibly be devised4 ,outer walls wind and moisture proof1 and inner walls of brick1 with an absolutely protected air space between1 insure strength and warmth4 ,an interior wall finish of the hardest and most non-absorbent materials known for such uses is a valuable hygienic provision1 and both safety and salubrity are further conserved by an absence of any hollow spaces between floors and ceilings1 or in stud partitions4 ,no vermin retreats1 no harbors for rodents1 no channels for flame exist4 ,heating is accomplished by indirect radiation with the steam supply from the power house1 but there are many open fireplaces to add to the complete stack and flue system of ventilation4 ,attached to the central group and completed are the kitchen building1 the laundry building and a dwelling house for employes1 which are so disposed in the rear of the group as to make a courtyard of value for the resort of patients1 as the main buildings protect and shelter it4 ,these buildings are ample for their work when the institution's full capacity is attained4 ,the kitchen building is a particularly interesting one4 ,all of the cooking is to be done there1 and a system of subways1 with tracks on which food cars are run1 connects it with all of the groups4 ,an idea of the magnitude of kitchen plans for such an institution may be got from one single fact4 ,the pantry is a lofty room1 #bjx#cb feet4 ,the calculation that #hj per cent4 of the insane of the district would be in the chronic stages of the disease explains the provision in detached cottage groups for this proportion of the patients4 ,a great proportion of these are feeble and helpless1 requiring constant attendance night and day1 but attendance that can be given cheaply and efficiently in associate day rooms1 dining rooms and large dormitories4 ,detached group ,no4 #a1 which is completed1 is an infirmary group for patients of both sexes of this class4 ,it is chiefly one story in height1 and the plan permits an abundance of sunlight and air for every room4 ,detached group ,no4 #b is intended for #ahe men of the chronic insane class1 who require more than ordinary care and observation4 ,detached group ,no4 #c is composed of two-story buildings for #cbb women4 ,it has several large work-shops4 ,occupation is one of the main reliances of the planners of the institution as a part of the treatment there4 ,detached group ,no4 #d is designed for both men and women1 and will accommodate #aej4 ,a wholly different classification is here provided for1 the actively industrious classes being intended for this group4 ,those who are able to do outdoor work1 and for whom some diverting employment will be beneficial in making them contented and physically healthy1 will live here4 ,there is complete separation of day rooms1 but the two sexes will dine together in an associate hall4 ,an amusement hall to harmonize with the central group1 and to be built adjacent to it1 is planned1 and will be built this year if the appropriation will permit4 ,it is a valuable and necessary adjunct to the other provisions for the care of a population of #a1ejj4 ,accommodations for entertainments1 chapel exercises1 dancing and a bathing establishment are included in the plans in a way that gives great results with great economy of construction4 ,probably the feature in the scheme of the ,st4 ,lawrence ,state ,hospital of the greatest popular and professional interest is ,dr4 ,wise's plan to have there an ,americanized and improved ,gheel4 ,the original ,gheel in ,belgium is a colony where for many years lunatics have been sent for domiciliary care4 ,its inhabitants1 mostly of the peasant class1 have grown accustomed to the presence and care of patients with disordered minds4 ,the system is the outgrowth of a superstition founded in the presumed miraculous cure of a lunatic whose reason was restored by the shock of the sight of the killing of a beautiful girl by her pursuing father1 whose fury had been roused by her choice of a husband4 ,a monument to this unfortunate graces ,gheel1 and as ,st4 ,dymphna she is supposed to be in benign control of the lunatic-sheltering colony4 ,some of the features of the ,gheel system of care are also distinctively known as the ,scotch system4 ,there the placing of patients in family care is common4 ,massachusetts has also adopted it to a considerable extent4 ,but there are many objections to family care in isolated domiciles1 as practiced in ,massachusetts4 ,special medical attention and official visits are made expensive and inconvenient4 ,dr4 ,wise plans to get all the advantages of such a mode of life for patients whose condition retrogrades under institutional influence4 ,not the least of these advantages is that of economy in relieving the ,state from the per capita cost of construction for at least one-fourth of the insane of the district4 ,he would utilize the families in the settlement which always grows up in the vicinity of a large hospital4 ,it is composed of the households of employes1 many of which are the result of marriages among the attendants and employes4 ,on ,point ,airy1 by the use of the buildings that were on the different plots bought by the ,state to make up the hospital farm1 such a settlement can be easily made up4 ,its inhabitants would pay rent to the ,state4 ,they would be particularly fit and proper persons to board and care for patients whose condition was suitable for that sort of a life1 and the patients could have many privileges and benefits not possible in the hospital4 ,point ,airy's little ,gheel on such a plan would be a most interesting and valuable extension of the beneficent rule of ,st4 ,dymphna4 ,the ,st4 ,lawrence ,state ,hospital was built and is operated under the supervision of a board of managers1 whose fidelity to it is described as phenomenal by the people of ,ogdensburg4 ,the members of the executive committee1 ,chairman ,william ,l4 ,proctor1 ,secretary ,a4,e4 ,smith1 ,john ,hannan and ,george ,hall1 especially ,mr4 ,proctor and ,mr4 ,smith1 have given as much time and attention to it as most men would to a matter in which they had a business interest4 ,the result has been a performance of contract obligations in which the ,state got its money's worth4 ,the people of ,ogdensburg1 too1 have taken a great interest in the institution4 ,such men as ,mayor ,edgar ,a4 ,newell1 ex-,collector of the ,port of ,new ,york ,daniel ,magone1 ,postmaster ,a4,a4 ,smith1 ,assemblyman ,george ,r4 ,malby1 and his predecessor1 ,gen4 ,n4,m4 ,curtis1 who was the legislative father of the hospital scheme2 ,frank ,tallman and ,amasa ,thornton take as much pride in the institution that the ,state has set down at the gates of their city as they do in their cherished and admired city hall1 which combines a tidy little opera house with the quarters necessary for all public and department uses4 ,the executive staff of the hospital consists of ,dr4 ,p4,m4 ,wise1 medical superintendent2 ,dr4 ,j4 ,montgomery ,mosher1 assistant3 ,dr4 ,j4,a4 ,barnette and ,steward ,w4,c4 ,hall4--,n4,y4 ,sun4 99 99 99 99 99 ,,the ,,electrical ,,purification ,,of ,,sewage ,,and ,,contaminated ,,water4 ,footnote3 ,recently read before the ,chemical ,society1 ,london4 ,from the ,journal of the ,society4 ,by ,,wm4 ,,webster4 ,the term sewage many years ago was rightly applied to the excremental refuse of towns1 but it is a most difficult matter to define the liquid that teems into our rivers under the name of sewage to-day2 in most towns chemical refuse is the best name for the complex fluid running from the sewers4 ,it is now more than ten years since ,i first commenced a series of experiments with a view of thoroughly testing various methods of purifying sewage and water contaminated with putrefying organic matter4 ,it was while investigating the action of iron salts upon organic matter in solution and splitting up the chlorides present by means of electrolysis1 that ,i first became aware of the importance of precipitating the soluble organic matter in such manner that no chemical solution should take the place of the precipitated organic matter4 ,if chemical matter is substituted for the organic compounds1 the cure is worse than the disease1 as the resulting solution in most cases sets up after precipitation in the river into which it flows4 ,my first electrolytical experiments were conducted with non-oxidizable plates of platinum and carbon1 but the cost of the first and the impossibility of obtaining carbon plates that would stand long-continued action of nascent chlorine and oxygen made it desirable that some modification should be tried4 ,i next tried the effect of electrolytic action when iron salts were present1 but did not think of using iron electrodes until after trying aluminum4 ,i found that the action of non-oxidizable electrodes was most efficacious after the temperature of the fluid acted upon rose #d or #e2 but the cost of working made it impossible on a large scale4 ,after a long series of experiments1 iron plates were used as electrodes1 with remarkable results1 for the compounds of iron formed not only deodorized the samples of sewage acted on1 but produced complete precipitation of the matters in suspension1 and also of the soluble organic matter2 the resulting effluents remaining perfectly free from putrefaction4 ,the first part of the process is well illustrated by the small experiments now shown2 the organic matter in suspension and in solution separates into flocculent particles1 which rise to the top of the liquid and remain until the bubbles of hydrogen which have carried them up escape1 when the solid matter will precipitate4 ,in the arrangement adopted on a working scale1 the separated particles precipitate readily4 ,as an illustration of the action upon organic matter in solution ,i take a small quantity of dye1 mix it with water1 and placing the connected iron electrodes in the mixture1 the dye in solution separates into flocculent particles4 ,the electrolytical action is of course easily understood1 but the chemical changes that take place need an explanation4 ,at the positive pole1 hypochlorite of iron seems to be formed at first1 but this is quickly changed into a protochloride1 and as at the negative pole an alkaline reaction takes place1 the iron salt is precipitated in the form of the ferrous hydrated oxide1 together with the organic matters in suspension and solution4 ,owing to the carbonates that are always present in sewage1 ferrous carbonate is also formed4 ,the success of these laboratory experiments led me to a trial of the process on a larger scale1 for hitherto only a gallon at any one time had been treated4 ,small brick tanks were erected at my wharf at ,peckham and iron electrodes fitted to them4 ,wrought iron plates were fixed about an inch apart1 and connected in parallel in the tanks1 forming one big cell4 ,sewage to the amount of about #bjj gallons was run into the electrode tank and then treated1 the results being so satisfactory that larger works were erected1 when a supply of sewage equal to #bj1jjj gallons an hour could be obtained4 ,after a number of experiments had been carried out it was decided to run the sewage as rapidly as possible through electrodes1 six cells or two rows in series fixed in a long channel or shoot1 for experience showed that the motion of the liquid acted on reduced the back ,e4,m4,f4 and hastened the formation of the precipitate4 ,a channel is kept at the bottom of the electrodes for the silt to collect1 with a culvert at side to flush it into1 so as to prevent any block occurring2 the advantage of this is obvious4 ,the plates in each section may be from half an inch to an inch thick1 and can be of any length up to #f ft4 ,it may possibly be objected that a large number of plates is required4 ,this may be so1 but the larger the number of plates1 the less the engine power required1 and the longer they last4 ,in each section the electrodes are in parallel1 and any one section is in series with the other1 the arrangement being exactly like that of a series of primary battery cells4 ,by actual experience ,i have been able to prove that at least #be sections of electrodes should be in series and across any one of these sections the potential difference need not be greater than #a4h volts1 the current being of any desired amount1 according to the surface of plates used4 ,the electrical measurements taken by ,dr4 ,john ,hopkinson during these experiments for the ,electrical ,purification ,association1 to whom ,i had sold my patents1 entirely corroborated my contentions as to ,e4,h4,p4 used1 and agreed with the measurements of the managing electrician1 ,mr4 ,octavius ,march4 ,the process was then thoroughly investigated by ,sir ,henry ,roscoe1 who had control of the works for one month4 ,he reports as follows3 ,the reduction of organic matter in solution is the crucial test of the value of a purifying agent1 for unless the organic matter is reduced1 the effluent will putrefy and rapidly become offensive4 ,i have not observed in any of the unfiltered effluents from this process which ,i have examined any signs of putrefaction1 but1 on the contrary1 a tendency to oxidize4 ,the absence of sulphureted hydrogen in samples of unfiltered effluent1 which have been kept for about six weeks in stoppered bottles1 is also a fact of importance4 ,the settled sewage was not in this condition1 as it rapidly underwent putrefaction1 even in contact with air1 in two or three days4 ,the results of this chemical investigation show that the chief advantages of this system of putrefaction are3 ,first4--,the active agent1 hydrated ferrous oxide1 is prepared within the sewage itself as a flocculent precipitate4 7,it is scarcely necessary to add that the inorganic salts in solution are not increased1 as in the case where chemicals in solution are added to the sewage47 ,not only does it act as a mechanical precipitant1 but it possesses the property of combining chemically with some of the soluble organic matter and carrying it down in an insoluble form4 ,second4--,hydrated ferrous oxide is a deodorizer4 ,third4--,by this process the soluble organic matter is reduced to a condition favorable to the further and complete purification by natural agencies4 ,fourth4--,the effluent is not liable to secondary putrefaction4 ,mr4 ,alfred ,e4 ,fletcher also investigated the process subsequently1 and reports as follows3 ,the treatment causes a reduction in the oxidizable matter in the sewage1 varying from #fj to #hj per cent4 ,the practical result of the process is a very rapid and complete clarification of the sewage1 which enables the sludge to separate freely4 ,it was noticed that while the raw sewage filters very slowly1 so that #ejj c4c4 required #if hours to pass through a paper filter1 the electrically treated sewage settled well and filtered rapidly4 ,samples of the raw sewage1 having but little smell when fresh1 stank strongly on the third day4 ,the treated samples1 however1 had no smell originally1 and remain sweet1 without putrefactive change4 ,in producing this result two agencies are at work1 there is the action of electrolysis and the formation of a hydrated oxide of iron4 ,it is not possible1 perhaps1 to define the exact action1 but as the formation of an iron oxide is part of it1 it seemed desirable to ascertain whether the simple addition of a salt of iron with lime sufficient to neutralize the acid of the salt would produce results similar to those attained by ,webster's process4 ,in order to make these experiments1 samples of fresh raw sewage were taken at ,crossness at intervals of one hour during the day4 ,as much as #aj grains of different salts of iron were added per gallon1 plus #ae4g grains of lime in some cases and #abe grains of lime in another1 and the treated sewage was allowed to settle twenty-four hours2 the results obtained were not nearly as good as the electrical method4 ,during the present year a very searching investigation of the merits of various processes of sewage treatment has been made by the corporation of ,salford2 among others of my electrical process4 ,as the matter is at present under discussion by the council1 ,i am not in a position to give extracts from the reports of the engineers and chemists under whose supervision and control the work was done1 but ,i may go so far as to say that the results of my system of electrical treatment have proved its efficiency and applicability to sewages of even such a foul nature as that of ,salford and ,pendleton4 ,the system was controlled continuously for the corporation by ,mr4 ,a4 ,jacob1 ,b4,a41 ,c4,e41 the borough engineer2 ,mr4 ,j4 ,carter ,bell1 ,f4,i4,c41 etc41 county analyst2 ,messrs ,john ,newton ,sons1 engineers1 ,manchester2 ,mr4 ,giles1 of ,messrs4 ,mather ,pratt1 electrical engineers1 ,manchester2 ,dr4 ,charles ,a4 ,burghardt1 lecturer in mineralogy at ,owens ,college4 ,i would also refer you to a paper recently read before the ,manchester ,section of this ,society by ,mr ,carter ,bell1 the borough analyst for ,salford1 in whose remarks ,dr4 ,burghardt1 an independent authority1 permits me to add that he concurs4 ,he cannot give details until his report has gone in1 which will be very shortly4 ,mr4 ,carter ,bell's report has gone in1 and although he is precluded also from giving full details1 he has kindly put at my disposal samples sealed by him of the effluents produced by the electrical treatment1 which ,i now submit1 together with the analyses in the table4 ,the samples are taken at random4 ,whether the process will or will not be adopted by the ,salford authorities ,i am of course unable to say1 but ,i think ,i may safely say that the electrical process has now absolutely proved its case in regard to the solution of the sewage problem4 ,it is simple1 efficient and1 ,i am sure1 more economical than any other known process where duration is taken into account4 ,in regard to the ,salford trials it may be interesting to give the following particulars3 ,parts in #ajj1jjj4 ,may #ae4 ,june #g4 ,june #cj4 ,july #be4 ,not filtered4 ,total solids4 #aji #abe #ada #acb ,loss on ignition4 #cc #ba #bi #bc ,chlorine4 #cb #dd #db #dc ,oxygen required for #ae minutes4 #b4ef #j4gf #j4bg #j4gi ,oxygen required for three hours4 #d4bg #j4gi #j4ej #a4jj ,free ammonia4 #b4bj #j4hh #j4ej #j4ib ,albuminoid am- monia4 #j4cb #j4ag #j4jib #j4ai ,the electrical shoot was built in brick and contained #bh cells arranged in series4 ,each cell contained #ac cast iron plates #d in4 #b ft4 #h in4 in4 thick connected in parallel4 ,the available electrode surface in each cell was #bef sq4 ft4 ,the ampere hour treatment required for ,salford was found to be about #j4cg ampere hours per gallon1 and the ,i4,h4,p4 per million gallons based on these figures would be #cg4 ,,note4--,in estimating for the plant necessary for treating the whole of the ,salford sewage1 a margin was allowed on above figures4 ,the ,a4,h4,t4 was taken at #j4d and the ,i4,h4,p4 per million at #ci to #ci4e4 ,mr4 ,octavius ,march1 electrical engineer1 who has followed the process from the commencement1 and who superintended the electrical details both at ,crossness and ,salford1 will give you on the blackboard a rough sketch of the above trial plant4 ,the ,salford tanks are admirably adapted to the application of the electrical or in fact any process of precipitation4 ,they are #ab in number1 and it is proposed to take two end tanks for the electrical channels1 in which the iron electrodes would be placed4 ,the total ,i4,h4,p4 required for treating the whole of the ,salford and ,pendleton sewage1 taken at #aj1jjj1jjj gallons per #bd hours1 is calculated at #djj ,i4,h4,p41 based on the actual work done during the trial4 ,the electrical plant would consist of four engines and dynamos1 any three of which could do the whole work1 and three boilers1 each of #bjj ,i4,h4,p4 ,the total cost of plant1 including alterations1 is estimated at #af1jjj1 to which must be added the cost of about #e1jjj tons of iron plates--ordinary cast iron--at say #d per ton4 ,these plates would last for several years4 ,if filtration were required1 there would be an extra expenditure for this1 but it will be remarked that as the treated sewage is practically purified when it leaves the electrical channels1 these filters would be only required for complete clarification1 which for most places would not be a necessity4 ,the filtering material used could be gradually prepared from the sludge obtained after electrical treatment1 unless it could be more profitably sold as a manure1 and ,i am not a believer in the value of sewage sludge in large quantities4 ,this sludge1 a waste product1 is converted into magnetic oxide of iron1 of which ,i have here two small samples4 ,this magnetic oxide is a good filtering material1 but1 like every other filtering material1 it would of course require renewal4 ,there would1 however1 always be a supply of the waste product--sewage sludge--on the spot1 and the spent magnetic oxide recarbonized could be used indefinitely4 ,the annual cost for dealing with the ,salford sewage is estimated at in round figures #b1ejj for coal1 labor1 maintenance of engines1 boilers and dynamos4 ,to this must be added the consumption of iron and its replacement1 which would have to be written off capital expenditure4 ,if a colorless effluent were required1 absolutely free from suspended matter1 the additional cost is estimated at from #a1bjj to #a1ejj4 99 99 99 99 99 ,,lavender ,,and ,,its ,,varieties4 ,by ,j4 ,,ch4 ,,sawer1 ,f4,l4,s4 ,lavender--technically ,lavandula4 ,this name is generally considered to be derived from the word lavando1 gerund of the verb lavare1 to wash or to bathe1 and to originate from the ancient ,roman custom of perfuming baths with the flowers of this plant4 ,the general aspect of the various species which compose this genus of labiate plants1 although presenting very characteristic differences1 merges gradually from one species to another2 all are1 in their native habitat1 small ligneous undershrubs of from one to two feet in height1 with a thin bark1 which detaches itself in scales2 the leaves are linear1 persistent1 and covered with numerous hairs1 which give the plant a hoary appearance4 ,the flowers1 which are produced on the young shoots1 approximate into terminal simple spikes1 which are1 in vigorous young plants1 branched at the base and usually naked under the spikes4 ,as a rule1 lavender is a native of the countries bordering on the great basin of the ,mediterranean--at least eight out of twelve species are there found to be indigenous on mountain slopes4 ,the most commonly known species are ,l4 vera1 ,l4 spica and ,l stchas4 ,commercially the ,l4 vera is the most valuable by reason of the superior delicacy of its perfume2 it is found on the sterile hills and stony declivities at the foot of the ,alps of ,provence1 the lower ,alps of ,dauphin and ,cevannes 7growing in some places at an altitude of #d1ejj feet above the sea level71 also northward1 in exposed situations1 as far as ,monton1 near ,lyons1 but not beyond the #dfth degree of latitude2 in ,piedmont as far as ,tarantaise1 and in ,switzerland1 in ,lower ,vallais1 near ,nyon1 in the canton of ,vaud1 and at ,vuilly4 ,it has been gathered between ,nice and ,cosni1 in the neighborhood of ,limon1 on the elevated slopes of the mountains of western ,liguria1 and in ,etruria on hills near the sea4 ,the ,l4 spica1 which is the only species besides ,l4 vera hardy in this country1 was formerly considered only a variety of ,l4 vera2 it is distinguished by its lower habit1 much whiter color1 the leaves more congested at the base of the branches1 the spikes denser and shorter1 the floral leaves lanceolate or linear1 and the presence of linear and subulate bractes4 ,it yields by distillation an oil termed oil of spike1 or1 to distinguish it from oil of ,l4 stchas1 true oil of spike4 ,it is darker in color than the oil of ,l4 vera1 and much less grateful in odor1 reminding one of turpentine and rancid coker nut oil4 ,it is used by painters on porcelain1 and in the manufacture of varnishes4 ,it is often largely admixed with essence of turpentine4 ,l4 ,stchas 7,stichas7 was discovered prior to the year #ej ,a4,d4 in the ,stchades ,islands 7now the ,islands of ,hyres71 hence the name4 ,at present it is found wild in the ,south of ,europe and ,north of ,africa1 also at ,teneriffe4 ,the leaves are oblong linear1 about half an inch long 7sometimes an inch long when cultivated71 with revolute edges and clothed with hoary tomentum on both surfaces2 the spike is tetragonal1 compact1 with a tuft of purple leaves at the top2 the calyces are ovate and slightly shorter than the tube of the corolla4 ,the whole plant has a strong aromatic and agreeable flavor4 ,there is a variety of this species 7,l4 macrostchya7 native of ,corsica1 ,sicily1 and ,naples1 which has broader leaves and thicker octagonal spikes4 ,l4 stchas is known in ,spain as ,romero ,santo 7sacred rosemary74 ,its essential oil 7also that of ,l4 dentata7 is there obtained for household use by suspending the fresh flowering stalks1 flowers downward1 in closed bottles and exposing them for some time in the sun's rays2 a mixture of water and essential oil collects at the bottom1 which is used as a hmostatic and for cleansing wounds4 ,the specific gravity of ,spanish oil of ,l4 stchas is #j4idb at #ae ,c4 ,it boils between #ahj and #bde4 ,the odor of this oil is not at all suggestive of that of lavender1 but resembles more that of oil of rosemary1 possessing also the camphoraceous odor of that oil4 ,in ,india this oil is much prized as an expectorant and antispasmodic4 ,illustration3 ,,lavandula ,,vera4 ,,lavandula ,,spica4 7,from photographs of the plants4 ,natural size47 ,the other species which are distinctly characterized are ,l4 pedunculata1 ,l4 viridis1 ,l4 dentata1 ,l4 heterophylla1 ,l4 pyrenaica1 ,l4 pinnata1 ,l4 coronopifolia1 ,l4 abrotonoides1 ,l4 ,lawii1 and ,l4 multifida4 ,the ,l4 multifida is synonymous with ,l4 ,burmanii4 ,in ,spain the therapeutic properties of ,l4 dentata are alleged to be even more marked than in the oils of any of the other species of lavender4 ,it is said to promote the healing of sluggish wounds1 and when used in the form of inhalation to have given good results in cases of severe catarrh1 and even in cases of diphtheria4 ,in odor this oil strongly suggests rosemary and camphor4 ,its specific gravity is #j4ibf at #ae ,c4 ,it distills almost completely between #agj and #bjj4 ,the specific gravity of the oil of ,l4 vera 7according to ,flckiger and ,hanbury1 ,pharmacographia7 ranges between #j4hg and #j4id4 ,the same authorities state that in a tube of #ej millimeters the plane of polarization is diverted #d4b to the left4 ,dr4 ,gladstone found 7,jnl4 ,ch4 ,soc41 xviii41 #c7 that a sample of pure oil of ,l4 vera1 obtained from ,dr4 ,s4 ,piesse1 indicated a specific gravity of #j4hijc at #ae ,c41 and that its power of rotating the plane of polarization 7observed with a tube ten inches long7 was -#bj4 ,compared with these results he found the sp4 gr4 of oil of turpentine to be #j4hgbg1 and the rotatory power -#gi4 ,although ,l4 stchas was well known to the ancients1 no allusion unquestionably referring to ,l4 vera has been found in the writings of classical authors1 the earliest mention of this latter plant being in the twelfth century1 by the ,abbess ,hildegard1 who lived near ,bergen-on-the-,rhine4 ,under the name of ,llafant or ,llafantly1 it was known to the ,welsh physicians as a medicinal plant in the thirteenth century4 ,the best variety of ,l4 vera--and there are several1 although unnamed--improved by cultivation in ,england1 presents the appearance of an evergreen undershrub of about two feet in height1 with grayish green linear leaves1 rolled under at the edges1 when young2 the branches are erect and give a bushy appearance to the plant2 the flowers are borne on a terminal spike1 at the summit of along naked stalk1 the spike being composed of six to ten verticillasters1 more widely separated toward the base of the spike2 in young plants two or four sub-spikes will branch alternately in pairs from the main stalk2 this indicates great vigor in the plant1 and occurs rarely after the second year of the plant's growth4 ,the floral leaves are rhomboidal1 acuminate1 and membraneous1 the upper ones being shorter than the calyces1 bracteas obovate2 the calyces are bluish1 nearly cylindrical1 contracted toward the mouth1 and ribbed with many veins4 ,the corolla is of a pale bluish violet1 of a deeper tint on the inner surface than the outer1 tubular1 two-lipped1 the upper lip with two and the lower with three lobes4 ,both the corolla and calyx are covered with stellate hairs1 among which are embedded shining oil glands1 to which the fragrance of the plant is due4 ,the ,l4 vera was identified in #aeda1 and introduced into ,england in #aefh1 flourishing remarkably well under cultivation1 and yielding an oil far superior in delicacy of fragrance to that obtained from the wild plant1 or to that obtained from the same plant cultivated in any other country4 ,when it is remembered that north of the #ejth degree of latitude the vine yields little but garlands of leaves1 and that we should attempt in vain to cultivate the olive north of the #ddth degree1 it may seem strange that the ,lavandula vera1 which is a native of about the same climate as these1 should resist1 unprotected1 the vigorous frosts of this country4 ,even at ,upsala1 latitude #ei #ea' ,n41 in the ,botanic ,garden1 it merely requires the shelter of a few branches to protect it in the winter2 but this hardiness may be accounted for by several physiological reasons4 ,like all fruticulose labiates which have a hard compact tissue and contain much oily matter1 the lavender absorbs less moisture than herbs which are soft and spongy1 and1 as it always prefers a dry calcareous1 even stony1 soil1 the northern cultivators find that by selecting such localities the tissues of the plant take up so little water that the frost does not injure them4 ,in a northern climate the length of the days in summer1 and the natural dryness of the air1 compensate in some measure the reduction of temperature1 and mature the plant only to the extent sufficient for the purpose for which it is grown4 ,perhaps the suspension of vital action during winter1 which must be more complete in northern latitudes1 as our frosts are more severe1 tends to preserve certain plants1 native of the south1 for it is observed that all plants are more sensitive to cold when vegetation is active than when it is at rest4 ,the vine is an instance of this4 ,on the other hand1 when the plant is cultivated further south than its natural boundary1 the same causes seem to exert their influence1 but in the reverse sense4 ,lavender is cultivated on the mountains of ,yemen1 in ,arabia2 the humidity1 increasing inversely to the latitude1 compensates the exhaling force of the sun's rays1 and the elevation of the locality the effects of the heat4 ,thus is confirmed1 both in north and south1 the law of vegetable physiology observed by ,de ,candolle1 in the temperate climates of ,france1 and published in his ,essai de ,geographie ,botanique1 that plants can best resist the effects of cold in a dry atmosphere1 and the effects of heat in a humid atmosphere4 ,a mild1 damp winter1 like the one of #ahhi-ahij1 does more harm than a hard1 seasonable frost1 as the plants are apt to make green shoots prematurely1 and the late frosts nip off these tender portions1 each of which would otherwise have produced a flower spike4 ,the very severe winter of #ahij-ahia did not kill so many plants as the one of #ahhi-ahij4 ,the stems and branches of lavender being ligneous and strong are able to resist the force of the wind1 and the plant thrives best in a perfectly open locality1 where the air circulates freely2 the oil and resin which it contains in abundance enable it to resist the parching action of the wind and sun4 ,thus1 on the most arid and sterile ground on the mountain sides in the south1 and especially in ,spain1 plants of this genus flourish with more vigor in the season when most other vegetation is scorched up by the ardent rays of the sun1 and the ,lavandula vera seems to have a predilection for such spots4 ,certainly the plants then assume a more stunted appearance than in richer soil1 but at the same time the perfume is stronger and sweeter4 ,the calyces become charged with oil glands1 and yield a greater abundance of volatile oil4 ,in a very moist soil the water penetrates too much into the tissues1 detaches the bark1 the plant blackens at the root1 and a white fungus attaches to the main stem and lower branches2 it becomes feeble1 diseased1 and dies4 ,a rich soil furnishes too much nutriment1 the plant grows very large and herbaceous1 becomes overcharged with water relative to its assimilating and elaboratory power1 especially if growing in a cold climate1 and the equilibrium of the chemical proportions necessary for the formation of natural juices becomes deranged at the expense of quantity and quality of the volatile oil produced4 ,these facts1 long ago pointed out by ,linnus1 have been verified in ,england4 ,some years ago a disease manifested itself in most of the plantations1 which1 not being understood by the growers1 was not remedied 7in fact1 is not generally understood and remedied at the present time71 the acreage under cultivation decreased1 and1 partly owing to this and a scarcity occasioned by a failure in the crop1 the price of the oil rapidly rose from #ejs4 to #bjjs4 per lb4 ,consequently1 with the continually increasing demand and the continued rise in price1 manufacturers of lavender water and of compound perfumes in which oil of lavender is a necessary ingredient commenced to buy the ,french oil1 and venders of the ,english oil commenced to adulterate largely the ,english with the ,french oil4 ,by degrees the ,french oil become almost entirely substituted in ,england for the ,english1 and at present it is difficult to purchase true ,english lavender water of a quality equal to that vended twenty years ago1 except at a few first class houses4 ,the exorbitant profits demanded by chemists and druggists1 and the incomprehensible will of the public to buy anything cheap1 however bad1 have encouraged a marvelous increase in the figures of the imports of ,french 7and ,german1 which is worse7 oil4 ,in #ahhj1 when the price had reached #abes4 per lb41 it was pointed out by an eminent ,london firm that unless the cultivation in ,england were extended1 the price would become prohibitive1 inferior oils would be introduced into the market1 and so destroy the popularity of this beautiful perfume4 ,the price still rising did1 in fact1 induce this importation1 and to this day the bulk of chemists and perfumers continue to use these foreign oils1 notwithstanding the fall in the price of the ,english oil4 ,the constant demand1 however1 in ,america 7where people will have things good7 will yet support the price of the genuine article--that is1 of the ,english oil1 which is the finest the world produces4 ,attempts were made by a ,french manufacturing perfumer to establish a plantation in the south of ,france of plants taken from parent stems grown in ,england4 ,the result was that the young plants deteriorated to their original condition--even there in their native habitat4 ,the character of a plant and the character of its produce depend even on more than a similarity of soil and geographical position4 ,it is asserted that a good judge can distinguish between the oils produced by two adjacent fields1 and the difference in odor is very apparent between the oils produced in ,hertfordshire and in ,surrey4 ,the oil produced in ,sussex is different from both4--,chemist and ,druggist4 99 99 99 99 99 ,,spectrum ,,of ,,the ,,sun ,,and ,,elements4 ,the ,johns ,hopkins ,university ,circular1 ,no4 #he1 issued in ,february1 contains ,prof4 ,rowland's report of progress in spectrum work4 ,the spectra of all known elements1 with the exception of a few gaseous ones1 or those too rare to be yet obtained1 have been photographed in connection with the solar spectrum1 from the extreme ultra-violet down to the ,d line1 and eye observations have been made on many to the limit of the solar spectrum4 ,a table of standard wave lengths of the impurities in the carbon poles extending to wave length #b1jjj has been constructed to measure wave lengths beyond the limits of the solar spectrum4 ,in addition to this1 maps of the spectra of some of the elements have been drawn up on a large scale1 ready for publication1 and the greater part of the lines in the map of the solar spectrum have been identified4 ,the following rough table of the solar elements has been constructed entirely according to ,prof4 ,rowland's own observations1 although1 of course1 most of them have been given by others3 ,elements in the ,sun1 arranged according to ,intensity and the ,number of ,lines in the ,solar ,spectrum4 ,according to intensity4 ,according to number4 ,calcium ,zirconium ,iron 7#b1jjj or more7 ,magnesium 7#bj or more7 ,iron ,molybdenum ,nickel ,sodium 7#aa7 ,hydrogen ,lanthanum ,titanium ,silicon ,sodium ,niobium ,manganese ,strontium ,nickel ,palladium ,chromium ,barium ,magnesium ,neodymium ,cobalt ,aluminum 7#d7 ,cobalt ,copper ,carbon 7#bjj or more7 ,cadmium ,silicon ,zinc ,vanadium ,rhodium ,aluminum ,cadmium ,zirconium ,erbium ,titanium ,cerium ,cerium ,zinc ,chromium ,glucinum ,calcium 7#ge or more7 ,copper 7#b7 ,manganese ,germanium ,scandium ,silver 7#b7 ,strontium ,rhodium ,neodymium ,glucinum 7#b7 ,vanadium ,silver ,lanthanum ,germanium ,barium ,tin ,yttrium ,tin ,carbon ,lead ,niobium ,lead 7#a7 ,scandium ,erbium ,molybdenum ,potassium 7#a7 ,yttrium ,potassium ,palladium ,doubtful ,elements4 ,iridium1 osmium1 platinum1 ruthenium1 tantalum1 thorium1 tungsten1 uranium4 ,not in ,solar ,spectrum4 ,antimony1 arsenic1 bismuth1 boron1 nitrogen1 csium1 gold1 indium1 mercury1 phosphorus1 rubidium1 selenium1 sulphur1 thallium1 praseodymium4 ,with respect to these tables1 ,prof4 ,rowland adds3 ,the substances under the head of ',not in the ,solar ,spectrum' are often placed there because the elements have few strong lines or none at all in the limit of the solar spectrum when the arc spectrum1 which ,i have used1 is employed4 ,thus1 boron has only two strong lines at #bdig4 ,again1 the lines of bismuth are all compound1 and so too diffuse to appear in the solar spectrum4 ,indeed1 some good reason generally appears for their absence from the solar spectrum4 ,of course1 there is but little evidence of their absence from the sun itself2 were the whole earth heated to the temperature of the sun1 its spectrum would probably resemble that of the sun very closely4 ,the powerful instrument used at ,baltimore for photographing spectra1 and the measuring engine constructed to fit the photographs so that its readings give the wave lengths of lines directly within #a_/ajj of a division on ,angstrm's scale1 give the foregoing results a weight superior to many others published4 99 99 99 99 99 ,,allotropic ,,forms ,,of ,,metals4 ,writing on some curious properties of metals and alloys1 ,mr4 ,w4,c4 ,roberts-,austen1 says the ,engineer1 remarks that the importance of the isomeric and allotropic states has been much neglected in the case of metals4 ,joule and ,lyon ,playfair showed1 in #ahdf1 that metals in different allotropic states possess different atomic volumes1 and ,matthiessen1 in #ahfj1 was led to the view that in certain cases where metals are alloyed they pass into allotropic states1 probably the most important generalization which has yet been made in connection with the molecular constitution of alloys4 ,instances of allotropy in pure metals are3 ,bolley's lead1 which oxidizes readily in air2 ,schutzenberger's copper2 ,fritsche' tin1 which falls to powder when exposed to exceptionally cold winter2 ,gore's antimony2 ,graham's palladium and allotropic nickel4 ,joule has also proved that1 when iron is released from its amalgam by distilling away the mercury1 the metallic iron takes fire on exposure to air1 and is therefore clearly different from ordinary iron4 99 99 99 99 99 ,a ,new ,catalogue of ,valuable ,papers ,contained in ,,scientific ,,american ,,supplement during the past ten years1 sent free of charge to any address4 ,,munn ,,co41 #cfa ,broadway1 ,new ,york4 99 99 99 99 99 ,,the ,,scientific ,,american ,architects and ,builders ,edition4 #b4ej a ,year4 ,single ,copies1 #be cts4 ,this is a ,special ,edition of the ,,scientific ,,american1 issued monthly--on the first day of the month4 ,each number contains about forty large quarto pages1 equal to about two hundred ordinary book pages1 forming1 practically1 a large and splendid ,,magazine ,,of ,,architecture1 richly adorned with elegant plates in colors and with fine engravings1 illustrating the most interesting examples of modern ,architectural ,construction and allied subjects4 ,a special feature is the presentation in each number of a variety of the latest and best plans for private residences1 city and country1 including those of very moderate cost as well as the more expensive4 ,drawings in perspective and in color are given1 together with full ,plans1 ,specifications1 ,costs1 ,bills of ,estimate1 and ,sheets of ,details4 ,no other building paper contains so many plans1 details1 and specifications regularly presented as the ,,scientific ,,american4 ,hundreds of dwellings have already been erected on the various plans we have issued during the past year1 and many others are in process of construction4 ,architects1 ,builders1 and ,owners will find this work valuable in furnishing fresh and useful suggestions4 ,all who contemplate building or improving homes1 or erecting structures of any kind1 have before them in this work an almost endless series of the latest and best examples from which to make selections1 thus saving time and money4 ,many other subjects1 including ,sewerage1 ,piping1 ,lighting1 ,warming1 ,ventilating1 ,decorating1 ,laying out of ,grounds1 etc41 are illustrated4 ,an extensive ,compendium of ,manufacturers' ,announcements is also given1 in which the most reliable and approved ,building ,materials1 ,goods1 ,machines1 ,tools1 and ,appliances are described and illustrated1 with addresses of the makers1 etc4 ,the fullness1 richness1 cheapness1 and convenience of this work have won for it the ,,largest ,,circulation of any ,architectural publication in the world4 ,a ,catalogue of valuable books on ,architecture1 ,building1 ,carpentry1 ,masonry1 ,heating1 ,warming1 ,lighting1 ,ventilation1 and all branches of industry pertaining to the art of ,building1 is supplied free of charge1 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