99 99 99 99 99 ,transcriber's ,note3 ,the original publication has been replicated faithfully except as listed near the end of this text4 ,text in italics is shown like this4 ,text emphasized with bold characters or other treatment is shown like this4 99 99 99 99 99 ,gas-,engines and ,producer-,gas ,plants ,a ,,practice ,,treatise ,,setting ,,forth ,,the ,,principles ,,of ,,gas-,,engines ,,and ,,producer ,,design1 ,,the ,,selection ,,and ,,installation ,,of ,,an ,,engine1 ,,conditions ,,of ,,perfect ,,operation1 ,,producer-,,gas ,,engines ,,and ,,their ,,possibilities1 ,,the ,,care ,,of ,,gas-,,engines ,,and ,,producer-,,gas ,,plants1 ,,with ,a ,,chapter ,,on ,,volatile ,,hydrocarbon ,,and ,,oil ,,engines ,,by ,r4 ,e4 ,,mathot1 ,m4,e4 ,member of the ,societe des ,ingenieurs ,civils de ,france1 ,institution of ,mechanical ,engineers1 ,association des ,ingenieurs de l',ecole des ,mines du ,hainaut of ,brussels ,,translated ,,from ,,original ,,french ,,manuscript ,,by ,,waldemar ,b4 ,,kaempffert ,,with ,a ,,preface ,,by ,,dugald ,,clerk1 ,m4 ,,inst4 ,c4,e41 ,f4,c4,s4 ,,illustrated ,,new ,,york ,,munn ,,company ,,office ,,of ,,the ,,scientific ,,american #cfa ,,broadway #aije ,,preface ,,to ,,mathot',s ,,gas-,,engines ,,and ,,producer-,,gas ,,plants ,,by ,,dugald ,,clerk1 ,m4 ,,inst4,c4,e41 ,f4,c4,s4 ,mr4 ,mathot1 the author of this interesting work1 is a well-known ,belgian engineer1 who has devoted himself to testing and reporting upon gas and oil engines1 gas producers and gas plants generally for many years past4 ,i have had the pleasure of knowing ,mr4 ,mathot for many years1 and have inspected gas-engines with him4 ,i have been much struck with the ability and care which he has devoted to this subject4 ,i know of no engineer more competent to deal with the many minute points which occur in the installation and running of gas and oil engines4 ,i have read this book with much interest and pleasure1 and ,i consider that it deals effectively and fully with all the principal detail points in the installation1 operation1 and testing of these engines4 ,i know of no work which has gone so fully into the details of gas-engine installation and up-keep4 ,the work clearly points out all the matters which have to be attended to in getting the best work from any gas-engine under the varying circumstances of different installations and conditions4 ,in my view1 the book is a most useful one1 which deserves1 and no doubt will obtain1 a wide public recognition4 ,,dugald ,,clerk4 ,march1 #aije4 ,,introduction ,the constantly increasing use of gas-engines in the last decade has led to the invention of a great number of types1 the operation and care of which necessitate a special practical knowledge that is not exacted by other motors1 such as steam-engines4 ,explosion-engines1 driven by illuminating-gas1 producer-gas1 oil1 benzin1 alcohol and the like1 exact much more care in their operation and adjustment than steam-engines4 ,indeed1 steam-engines are regularly subjected to comparatively low pressures4 ,the temperature in the cylinders1 moreover1 is moderate4 ,on the other hand1 the explosion-motor is irregularly subjected to high and low pressures4 ,the temperature of the gases at the moment of explosion is exceedingly high4 ,it is consequently necessary to resort to artificial means for cooling the cylinder2 and the manner in which this cooling is effected has a very great influence on the operation of the motor4 ,if the cooling be effected too rapidly1 the quantity of gas consumed is considerably increased2 if the cooling be effected too slowly1 the motor parts will quickly deteriorate4 ,in order to reduce the gas consumption to a minimum1 a matter which is particularly important when the motor is driven by street-gas1 the explosive mixture is compressed before ignition4 ,only if all the parts are built with joints absolutely gas-tight is it possible to obtain this compression4 ,the slightest leakage past the valves or around the piston will sensibly increase the consumption4 ,the mixture should be exploded at the exact moment the piston starts on its working stroke4 ,if ignition occurs too soon or too late1 the result will be a marked diminution in the useful effect produced by the expansion of the gas4 ,all ignition devices are composed of delicate parts1 which cannot be too well cared for4 ,it follows from what has thus far been said that the causes of perturbation are more numerous in a gas than in a steam engine2 that with a gas-engine1 improper care will lead to a much greater increase in consumption than with a steam-engine1 and will cause a waste in power which would hardly be appreciable in steam-engines1 whether their joints be tight or not4 ,it is the purpose of this manual to indicate the more elementary precautions to be taken in the care of an engine operating under normal conditions1 and to explain how repairs should be made to remedy the injuries caused by accidents4 ,engines which are of less than #bjj horse-power and which are widely used in a small way will be primarily considered4 ,in another work the author will discuss more powerful engines4 ,before considering the choice1 installation1 and operation of a gas-engine1 it will be of interest to ascertain the relative cost of different kinds of motive power4 ,disregarding special reasons which may favor the one or the other method of generating power1 the net cost per horse-power hour will be considered in each case in order to show which is the least expensive method of generating power in ordinary circumstances4 ,r4 ,e4 ,,mathot4 ,,march1 #aije4 ,,table ,,of ,,contents ,,chapter ,i ,,page ,,motive ,,power ,,and ,,cost ,,of ,,installation #ag ,,chapter ,,ii ,,selection ,,of ,,an ,,engine ,the ,otto ,cycle4--,the ,first ,period4--,the ,second ,period4--,the ,third ,period4--,the ,fourth ,period4--,valve ,mechanism4--,ignition4-- ,incandescent ,tubes4--,electric ,ignition4--,electric ,ignition by ,battery and ,induction-,coil4--,ignition by ,magnetos4--,the ,piston4-- ,arrangement of the ,cylinder4--,the ,frame4--,fly-,wheels4--,straight and ,curved ,spoke ,fly-,wheels4--,the ,crank-,shaft4--,cams1 ,rollers1 etc4--,bearings4--,steadiness4--,governo rs4--,vertical ,engines4-- ,power of an ,engine4--,automatic ,starting #ba ,,chapter ,,iii ,,the ,,installation ,,of ,,an ,,engine ,location4--,gas-,pipes4--,dry ,meters4--,wet ,meters4--,anti-,pulsators1 ,bags1 ,pressure-,regulators4--,precautions4--, air ,suction4-- ,exhaust4--,legal ,authorization #fi ,,chapter ,,iv ,,foundation ,,and ,,exhaust ,the ,foundation ,materials4--,vibration4--,air ,vibration1 etc4-- ,exhaust ,noises #hg ,,chapter ,v ,,water ,,circulation ,running ,water4--,water-,tanks4--,coolers #ih ,,chapter ,,vi ,,lubrication ,quality of ,oils4--,types of ,lubricators #aaa ,,chapter ,,vii ,,conditions ,,of ,,perfect ,,operation ,general ,care4--,lubrication4--,tightness of the ,cylinder4-- ,valve-,regrinding4--,bearings4--,crossh ead4--,governor4--,joints4-- ,water ,circulation4--,adjustment #aba ,,chapter ,,viii ,,how ,,to ,,start ,,an ,,engine4--,,preliminary ,,precautions ,care during ,operation4--,stopping the ,engine #abh ,,chapter ,,ix ,,perturbations ,,in ,,the ,,operation ,,of ,,engines ,,and ,,their ,,remedy ,difficulties in ,starting4--,faulty ,compression4--,pressure of ,water in the ,cylinder4--,imperfect ,ignition4--,electric ,ignition by ,battery or ,magneto4--,premature ,ignition4--,untimely ,detonations4--,retarded ,explosions4--,lost ,motion in ,moving ,parts4--,overheated ,bearings4--,overheating of the ,cylinder4-- ,overheating of the ,piston4--,smoke arising from the ,cylinder4-- ,back ,pressure to the ,exhaust4--,sudden ,stops #acd ,,chapter ,x ,,producer-,,gas ,,engines ,high ,compression4--,cooling4--,premature ,ignition4--,the ,governing of ,engines #aec ,,chapter ,,xi ,,producer-,,gas ,street-,gas4--,composition of ,producer-,gases4--,symptoms of ,asphyxiation4--,gradual1 ,rapid ,asphyxiation4--,slow1 ,chronic ,asphyxiation4--,first ,aid in ,cases of ,carbon ,monoxide ,poisoning4--,sylvester ,method4--,pacini ,method4--,impurities of the ,gases #afe ,,chapter ,,xii ,,pressure ,,gas-,,producers ,dowson ,producer4--,generators4--,air-,blast4-- ,blowers4--,fans4-- ,compressors4--,exhausters4--,washing and ,purifying4-- ,gas-,holder4--,lignite and ,peat ,producers4--,distilling-,producers4-- ,producers ,using ,wood ,waste1 ,sawdust1 and the like4-- ,combustion-,generators4--,inverted ,combustion #agd ,,chapter ,,xiii ,,suction ,,gas-,,producers ,advantages4--,qualities of ,fuel4--,general ,arrangement4-- ,generator4--,cylindrical ,body4--,refractory ,lining4--,grate and ,support for the ,lining4--,ash-pit4--,charging-,box4-- ,slide-,valve4--,cock4--,feed-,hopper4-- ,connection of ,parts4--,air ,supply4--,vaporizer4--,preheaters4--,in ternal ,vaporizers4-- ,external ,vaporizers4--,tubular ,vaporizers4--,partition ,vaporizers4--,operation of the ,vaporizers4--,air-,heaters4-- ,dust-,collectors4--,cooler1 ,washer1 ,scrubber4--,purifying ,apparatus4--,gas-,holders4--,drier4--,p ipes4--,purifying-,brush4-- ,conditions of ,perfect ,operation of ,gas-,producers4-- ,workmanship and ,system4--,generator4--,vaporizer4--,scr ubber4-- ,assembling the ,plant4--,fuel4--,how to ,keep the ,plant in ,good ,condition4--,care of the ,apparatus4--,starting the ,fire for the ,gas-,producer4--,starting the ,engine4--,care of the ,generator during ,operation4--,stoppages and ,cleaning #aii ,,chapter ,,xiv ,,oil ,,and ,,volatile ,,hydrocarbon ,,engines ,oil-,engines4--,volatile ,hydrocarbon ,engines4--,comparative ,costs4-- ,tests of ,high-,speed ,engines4--,the ,manograph4--,the ,continuous ,explosion-,recorder for ,high-,speed ,engines4--,records #bfd ,,chapter ,,xv ,,the ,,selection ,,of ,,an ,,engine ,the ,duty of a ,consulting ,engineer4--,specifications4--,testing the ,plant4--,explosion-,recorder for ,industrial ,engines4--,analysis of the ,gases4--,witz ,calorimeter4--,maintenance of ,plants4--,test of ,stockport ,gas-,engine with ,dowson ,pressure ,gas-,producer4--,test of a ,winterthur ,engine4--,test of a ,winterthur ,producer-,gas ,engine4--,test of a ,deutz ,producer-,gas ,engine and ,suction ,gas-,producer4--,test of a #bjj-;,h4,p4 ,deutz ,suction ,gas-,producer and ,engine #bgi ,,chapter ,i ,,motive ,,power--,,cost ,,of ,,installation ,the ease with which a gas-engine can be installed1 compared with a steam-engine is self-evident4 ,in places where illuminating gas can be obtained and where less than #aj to #ae horse-power is needed1 street-gas is ordinarily employed4,a ,the improvements which have very recently been made in the construction of suction gas-generators1 however1 would seem to augur well for their general introduction in the near future1 even for very small powers4 ,the installation of small street-gas-engines involves simply the making of the necessary connections with gas main and the mounting of the engine on a small base4 ,an economical steam-engine of equal power would necessitate the installation of a boiler and its setting1 the construction of a smoke-stack1 and other accessories1 while the engine itself would require a firm base4 ,without exaggeration it may be asserted that the installation of a steam-engine and of its boiler requires five times as much time and trouble as the installation of a gas-engine of equal power1 without considering even the requirements imposed by storing the fuel 7,fig4 #a74 ,small steam-engines mounted on their own boilers1 or portable engines1 the consumption of which is generally not economical1 are not here taken into account4 ,illustration3 ,,fig4 #a4--cj ,h4,p4 ,gas-engine and suction gas-producer4 ,illustration3 ,,fig4 #a;,a4--#cj ,h4,p4 ,steam-engine1 boiler and smoke-stack4 ,so far as the question of cost is concerned1 we find that a #ae to #bj horse-power steam-engine working at a pressure of #ij pounds and having a speed of #fj revolutions per minute would cost about #af-b_/c per cent4 more than a #ae horse-power gas-engine1 with its anti-pulsators and other accessories4 ,the foundation of the steam-engine would likewise cost about #af-b_/c per cent4 more than that of the gas-engine4 ,furthermore the installation of the steam-engine would mean the buying of piping1 of a boiler of #ajj pounds pressure1 and of firebrick1 and the erection of a smoke-stack having a height of at least #fe feet4 ,beyond a little excavating for the engine-base and the necessary piping1 a gas-engine imposes no additional burdens4 ,it may be safely accepted that the steam-engine of the power indicated would cost approximately #de per cent4 more than the gas-engine of corresponding power4 ,the cost of running a #ae to #bj horse-power steam-engine is likewise considerably greater than that of running a gas-engine of the same size4 ,considering the fuel-consumption1 the cost of the lubricating oil employed1 the interest on the capital invested1 the cost of maintenance and repair1 and the salary of an engineer1 it will be found that the operation of the steam-engine is more expensive by about #bc per cent4 ,this economical advantage of the gas over the steam-engine holds good for higher power as well1 and becomes even more marked when producer-gas is used instead of street-gas4 ,comparing1 for example1 a #ej horse-power steam-engine having a pressure of #ij pounds and a speed of #fj revolutions per minute1 with a #ej horse-power producer-gas engine1 and considering in the case of the steam-engine the cost of a boiler of suitable size1 foundation1 firebrick1 smoke-stack1 etc41 and in the case of the gas-engine the cost of the producer1 foundation1 and the like1 it will be found that the installation of a steam-engine entails an expenditure #ae per cent4 greater than in the case of the producer-gas engine4 ,however1 the cost of operating and maintaining the steam-engine of #ej horse-power will be #dj per cent4 greater than the operation and maintenance of the producer-gas engine4 ,from the foregoing it follows that from #ae to #bj up to #ejj horse-power the engine driven by producer-gas has considerably the advantage over the steam-engine in first cost and maintenance4 ,for the development of horse-powers greater than #ejj1 the employment of compound condensing-engines and engines driven by superheated steam considerably reduces the consumption1 and the difference in the cost of running a steam- and gas-engine is not so marked4 ,still1 in the present state of the art1 superheated steam installations entail considerable expense for their maintenance and repair1 thereby lessening their practical advantages and rendering their use rather burdensome4 ,,footnotes3 ,a ,recent improvements made in suction gas-producers will probably lead to the wide introduction of producer gas engines even for small power4 ,,chapter ,,ii ,,the ,,selection ,,of ,,an ,,engine ,explosion-engines are of many types4 ,gas-engines1 of the four-cycle type1 such as are industrially employed1 will here be principally considered4 ,the ,otto ,cycle4--,the term four-cycle motor1 or ,otto engine1 has its origin in the manner in which the engine operates4 ,a complete cycle comprises four distinct periods which are diagrammatically reproduced in the accompanying drawings4 ,the ,first ,period4--,suction3 ,the piston is driven forward1 creating a vacuum in the cylinder1 and simultaneously drawing in a certain quantity of air and gas 7,fig4 #b74 ,illustration3 ,,fig4 #b4--;,first cycle3 ,suction4 ,the ,second ,period4--,compression3 ,the piston returns to its initial position4 ,all admission and exhaust valves are closed 7,fig4 #c74 ,the mixture drawn in during the first period is compressed4 ,the ,third ,period4--,explosion and ,expansion3 ,when the piston has reached the end of its return stroke1 the compressed mixture is ignited4 ,explosion takes place at the dead center4 ,the expansion of the gas drives the piston forward 7,fig4 #d74 ,illustration3 ,,fig4 #c4--,second cycle3 ,compression4 ,illustration3 ,,fig4 #d4--,third cycle3 ,explosion and expansion4 ,the ,fourth ,period4--,exhaust3 ,the piston returns a second time4 ,the exhaust-valve is opened1 and the products of combustion are discharged 7,fig4 #e74 ,illustration3 ,,fig4 #e4--;,fourth cycle3 ,exhaust4 ,these various cycles succeed one another1 passing through the same phases in the same order4 ,valve ,mechanism4--,it is to be noted that in modern motors valves are used which are better adapted to the peculiarities of explosion-engines than were the old slide-valves used when the ,otto engine was first introduced4 ,the slide-valve may now be considered as an antiquated distributing device with which it is impossible to obtain a low consumption4 ,in old-time gas-engines rather low compressions were used4 ,consequently a very low explosive power of the gaseous mixture1 and low temperatures were obtained4 ,the slide-valves were held to their seats by the pressure of external springs1 and were generously lubricated4 ,under these conditions they operated regularly4 ,nowadays1 the necessity of using gas-engines which are really economical has led to the use of high compressions with the result that powerful explosions and high temperatures are obtained4 ,under these conditions slide-valves would work poorly4 ,they would not be sufficiently tight4 ,to lubricate them would be difficult and ineffective4 ,furthermore1 large engines are widely used in actual practice1 and with these motors the frictional resistance of large slide-valves1 moving on extensive surfaces would be considerable and would appreciably reduce the amount of useful work performed4 ,illustration3 ,,fig4 #f4--,modern valve mechanism4 ,by reason of its peculiar operation1 the slide-valve is objectionable1 the gases being throttled at the time of their admission and discharge4 ,as a result of these objections there are losses in the charge2 and obnoxious counter-pressures occur4 ,the necessity of using elements simple in their operation and free from the objections which have been mentioned1 has naturally led to the adoption of the present valve4 ,this valve is used both for the suction of the gas and of the air1 as well as for the exhaust1 with the result that either of these two essential phases in the operation of the motor can be independently controlled4 ,the valves offer the following advantages3 ,their tightness increases with the pressure1 since they always open toward the interior of the cylinder 7,fig4 #f74 ,they have no rubbing surfaces1 and need not1 therefore1 be lubricated4 ,their opening is controlled by levers provided with quick-acting cams2 and their closure is effected by coiled springs almost instantaneous in their action 7,fig4 #g74 ,each valve1 depending upon the purpose for which it is used1 can be mounted in that part of the cylinder best suited for its particular function4 ,the types of valved motors now used are many and various4 ,in order to attain economy in consumption and regularity in operation they should meet certain essential requirements which will here be reviewed4 ,apart from proportioning the areas properly and from providing a suitable means of operation1 it is indispensable that the valves should be readily accessible4 ,indeed1 the valves should be regularly examined1 cleaned and ground4 ,it follows that it should be possible to take them apart easily and quickly4 ,illustration3 ,,fig4 #g4--;,controlling mechanism of valve4 ,it is necessary that the exhaust-valve be well cooled2 otherwise the valve1 exposed as it is to high temperatures1 will suffer derangement and may cause leakage4 ,the water-jacket should1 therefore1 surround the seat of the exhaust-valve1 care being taken that the cooling water be admitted as near to it as possible 7,fig4 #h74 ,the motor should control the air-let valve or that of the gaseous mixture4 ,hence these valves should not be actuated simply by springs1 because springs are apt to move under the influence of the vacuum produced by suction4 ,illustration3 ,,fig4 #h4--,water-jacketed valve4 ,the mixture of gas and air should not be admitted into the cylinder at too low a pressure2 otherwise the weight of the mixture admitted would be lower than it ought to be1 inasmuch as under these conditions the valve will be opened too tardily and closed prematurely4 ,at the beginning as well as at the end of its stroke the linear velocity of the piston is quite inadequate to create a vacuum sufficient to overcome the resistance of the spring4 ,it is1 therefore1 generally the practice separately to control the opening or closing of the one or the other valve 7gas-valve or mixture-valve74 ,consequently these valves must be actuated independently of each other4 ,nowadays they are mechanically controlled almost exclusively1--a method which is advocated by well-known designers for industrial motors in particular4 ,valves which are not actuated in this manner 7free valves7 have only the advantage of simplicity of operation4 ,nevertheless1 this arrangement is still to be found in certain oil and benzine engines1 notably in automobile-motors4 ,in these motors it is necessary to atomize the liquid fuel by means of aspired air1 in order to produce an explosive1 gaseous mixture4 ,ignition4--,in the development of the gas-engine1 the incandescent tube and the electric spark have taken the place of the obsolete naked flame4 ,the last-mentioned mode of exploding the gaseous mixture will not1 therefore1 be discussed4 ,the hot tube of porcelain or of metal has the indisputable merit of regularity of operation4 ,the methods by which this operation is made as perfect as possible are many4 ,since certainty of ignition is obtained by means of the tube1 it is important to time the ignition1 so that it shall occur exactly at the moment when the piston is at the dead center4 ,it has been previously stated that premature or belated ignition of the explosive mixture appreciably lessens the amount of useful work performed by the expansion of the gas4 ,if ignition occur too soon1 the mixture will be exploded before the piston has reached the dead center on its return stroke4 ,as a result1 the piston must overcome a considerable resistance due to the premature explosion and the consequent pressure4 ,furthermore1 by reason of the high temperature of explosion1 the gaseous products are very rapidly cooled4 ,this rapid cooling causes a sudden drop in the pressure2 and since a certain interval elapses between the moment of explosion and the moment when the piston starts on its forward stroke1 the useful motive effort is the more diminished as the ignition is more premature4 ,incandescent ,tubes4--,in ,figs4 #i and #aj two systems most commonly used are illustrated4 ,in these two arrangements1 in which no valve is used1 the length or height to which the tube is heated by the outer flame is so controlled that the gaseous mixture1 which has been driven into the tube after compression1 reaches the incandescent zone as nearly as possible at the exact moment when ignition and explosion should take place4 ,the temperature of the flame of the burner1 the richness of the gaseous mixture1 and other circumstances1 however1 have a marked influence on the time of ignition1 so that the mixture is never fired at the exact moment mentioned4 ,illustration3 ,,figs4 #i-aj4--,valveless hot tubes4 ,these considerations lead to the conclusion that motors in which the mixture is exploded by hot tubes provided with an ignition-valve are preferable to valveless tubes4 ,by the use of a special valve1 positively controlled by the motor itself1 the chances of untimely ignition are lessened1 because it is necessary simply to regulate the temperature and the position of the tube in order that ignition may be surely effected immediately upon the opening of the valve1 at the very moment the cylinder gases come into contact with the incandescent portion of the tube 7,fig4 #aa74 ,many manufacturers1 however1 do not employ the ignition-valve on motors of less than #ae to #bj horse-power1 chiefly because of the cheaper construction4 ,the total consumption is of less moment in a motor of small than of great power1 and the loss due to the lack of an ignition-valve not so marked4 ,in a high-power engine1 premature explosion may be the cause of the breaking of a vital part1 such as the piston-rod or the crank-shaft4 ,for this reason1 a valve is indispensable for engines of more than #bj to #be horse-power4 ,a breakage of this kind is less to be feared in a small motor1 where the parts are comparatively stout4 ,the gas consumption of a well-designed burner does not exceed from #c4e to #e cubic feet per hour4 ,illustration3 ,,fig4 #aa4--;,ignition-tube with valve4 ,electric ,ignition4--,electric ignition consists in producing a spark in the explosion-chamber of the engine4 ,the nicety with which it can be controlled gives it an undeniable advantage over the hot tube4 ,but the objection has been raised1 perhaps with some force1 that it entails certain complications in installing the engine4 ,its opponents even assert that the power and the rapidity of the deflagration of the explosive mixture are greater with hot-tube ignition4 ,this reason may have caused the hot-tube system to prevail in ,england1 where manufacturers of gas-engines are very numerous and not lacking in experience4 ,electric ignition is effected in gas-engines by means of a battery and spark-coil1 or by means of a small magneto machine which mechanically produces a current-breaking spark4 ,illustration3 ,,fig4 #ab4--;,electric ignition by spark-coil and battery4 ,illustration3 ,,fig4 #ac4--,spark-plug4 ,electric ,ignition by ,battery and ,induction-,coil4--,the first system is the cheaper2 but it exacts the most painstaking care in maintaining the parts in proper working condition4 ,it comprises three essential elements--a battery1 a coil1 and a spark-plug 7,fig4 #ab74 ,the battery may be a storage-battery1 which must1 consequently1 be recharged from time to time2 or it may be a primary battery which must be frequently renewed and carefully cleaned4 ,the induction-coil is fitted with a trembler or interrupter1 which easily gets out of order and which must be regulated with considerable accuracy4 ,the spark-plug is a particularly delicate part1 subject to many possible accidents4 ,the porcelain of which it is made is liable to crack4 ,it is hard to obtain absolutely perfect insulation2 for the terminals deteriorate as they become overheated1 break1 or become foul 7,fig4 #ac74 ,in oil-engines1 especially1 soot is rapidly deposited on the terminals1 so that no spark can be produced4 ,in benzine or naphtha motors1 such an accident is less likely to happen4 ,in automobile-motors1 however1 the spark-plug only too often fails to perform its function4 ,the one remedy for these evils is to be found in the most painstaking care of the spark-plug and of the other elements of the ignition system4 ,illustration3 ,,fig4 #ad4--,magneto ignition apparatus4 ,illustration3 ,,fig4 #ae4--;,general view and details of a magneto ignition apparatus4 ,ignition by ,magnetos4--,magneto apparatus1 on the other hand1 are noteworthy for the regularity of their operation4 ,they may be used for several years without being remagnetized1 and require no exceptional care4 ,magneto ignition devices are mechanically actuated1 the necessary displacement of the coil being effected by means of a cam carried on a shaft turning with half the motor speed 7,figs4 #ad and #ae74 ,at the moment when it is released by the cam1 the coil is suddenly returned to its initial position by means of a spring4 ,this rapid movement generates a current that passes through terminals1 which are arranged within the cylinder and which are immediately separated by mechanical means4 ,thus a much hotter circuit-breaking spark is produced1 which is very much more energetic than that of a battery and induction-coil1 and which surely ignites the gaseous mixture in the cylinder4 ,the terminals are generally of steel1 sometimes pointed with nickel or platinum 7,fig4 #af74 ,the only precaution to be observed is the exclusion of moisture and occasional cleaning4 ,for engines driven by producer-gas magneto-igniters are preferable to cells and batteries4 ,in general1 electrical ignition is to be recommended for high-pressure engines4 ,illustration3 ,,fig4 #af4--;,contacts of a magneto-igniter4 ,illustration3 ,,fig4 #ag4--;,device for regulating the moment of ignition4 ,in order to explain more clearly modern methods of ignition a diagram is presented1 showing an electric magneto-igniter applied to the cylinder-head of a ,winterthur motor1 and also a sectional view of the member varying the make-and-break contacts which are mounted in the explosion-chamber 7,figs4 #ah and #ai7 #a4 ,the magneto ,a consists of horseshoe-magnets1 between the poles of which the armature rotates4 ,at its conically turned end1 the armature-shaft carries an arm ,b1 held in place by a nut4 ,illustration3 ,,fig4 #ah4--,winterthur electric ignition system4 #b4 ,the igniter ,c is a casting secured to the cylinder-head by a movable strap and provided with two axes ,d and ,m1 of which the one1 ,d1 made of bronze1 is movable1 and is fitted with a small interior contact-hammer1 a percussion-lever1 and an exterior recoil-spring2 the other1 ,m1 is fixed1 insulated1 and arranged to receive the current from the magneto ,a1 by means of an insulated copper wire ,e4 #c4 ,the spring ,f comprises two continuous coils contained in a brass casing1 and actuating a steel striking or percussion-pin4 #d4 ,the controlling devices of the magneto include a stem or rod ,g1 slidable in a guide ,h1 provided with a safety spring and mounted on an eccentric spindle1 the position of which can be varied by means of a regulating-lever 7,i74 ,the rod is operated from the distributing-shaft1 on the conical end of which a cam ,j carrying a spindle is secured4 ,illustration3 ,,fig4 #ai4--;,contacts of the ,winterthur system4 ,regulation of the ,magneto4--,the position assumed by the armature when at rest is a matter of importance in obtaining a good spark on breaking the circuit4 ,the marks on the armature should be noted4 ,the position of the armature may be experimentally varied1 in order to obtain a spark of maximum intensity1 by changing the position of the arm ,b on the armature-shaft4 ,control of the ,magneto4--,the controlling gear should enable the armature to oscillate from #bj to #be degrees4 ,the time at which the breaking of the circuit is effected can be regulated by shifting the handle 7,i74 ,in starting the engine1 the circuit can be broken with a slight retardation1 which is lessened as the engine attains its normal speed4 ,igniter4--,it is advisable that there should be a play of #a_/b mm4 7#j4jaif in47 between the lever ,z when at rest and the striking-pin4 ,the axis ,d of the circuit-breaking device should be easily movable2 and the hammer which it carries at its end toward the interior of the cylinder should be in perfect contact with the stationary spindle ,m1 which is electrically insulated4 ,this spindle ,m should be well enclosed1 in order to prevent any leakage that might cause a deterioration of the insulating material4 ,the subject of ignition is of such extreme importance that the author will recur to it from time to time in the various chapters of this book4 ,too much stress cannot be laid upon proper timing2 otherwise there will be a needless waste of power4 ,cleanliness is a point that must be observed scrupulously2 for spark-plugs are apt to foul only too readily1 with the result that short-circuits and misfires are apt to occur4 ,in oil and volatile hydrocarbon engines the tendency to fouling is particularly noticeable4 ,in the chapter devoted to these forms of motors the author has dwelt upon the precautions that should be taken to forestall a possible derangement of the ignition apparatus4 ,as a general rule the ignition apparatus installed by trustworthy manufacturers will be found best suited for the requirements of the engine4 ,the apparatus should be fitted with a device by which the ignition can be duly timed by hand during operation 7,fig4 #ag74 ,illustration3 ,,fig4 #bj4--;,design of the piston4 ,the ,piston4--,coming1 as it does1 continually in contact with the ignited gases1 the piston is gradually heated to a high temperature4 ,the rear face of the piston should preferably be plane4 ,curved surfaces are not to be recommended because they cool off badly4 ,likewise1 faces having either inserted parts or bolt-heads are to be avoided1 since they are liable to become red-hot and to ignite the mixture prematurely 7,fig4 #bj74 ,illustration3 ,,fig4 #ba4--,piston with lubricated pin4 ,among the parts of the piston which rapidly wear away because constant lubrication is difficult1 is the connection with the piston-rod 7,fig4 #ba74 ,it is important that the bearing at the piston-pin be formed of two parts which can be adjusted to take up the wear4 ,the pin itself should be of case-hardened steel4 ,for large engines1 some manufacturers have apparently abandoned the practice of locking the pin1 by set-screws1 in flanges cast in one piece with the piston4 ,indeed1 the piston is often fractured by reason of the expansion of the pins thus held on two sides4 ,it seems advisable to secure the pin by means of a single screw in one of the flanges1 fitting it by pressure against the opposite boss4 ,the use of wedges or of clamping-screws1 introduced from without the piston to hold the pin1 should be avoided4 ,it may happen that the wedges will be loosened1 will move out1 and will grind the cylinder1 causing injuries that cannot be detected before it is too late4 ,the strength of the piston-pin should be so calculated that the pressure per square inch of projected surface does not exceed #a1ejj to #b1hej pounds per square inch4 ,it should be borne in mind that the initial pressure of the explosion is often equal to #djj to #dbe pounds per square inch4 ,some manufacturers mount the pin as far to the back of the piston as possible1 so as to bring it nearer the point of application of the motive force of the explosion4 ,other manufacturers1 on the other hand1 mount the pin toward the front of the piston4 ,no great objection can be raised against either method4 ,in the former case the position of the rings will limit that of the pin4 ,the number of these rings ought not to be less than four or five1 arranged at the rear of the piston4 ,it is to be observed that makers of good engines use as many as #h to #aj rings in the pistons of fair-sized motors4 ,piston-rings of gray pig-iron can be adjusted with the greatest nicety in such a manner that1 by means of tongues fitting in their grooves1 they are held from turning in the latter1 whereby their openings are prevented from registering and allowing the passage of gas4 ,as a general rule1 a large number of rings may be considered a distinguishing feature of a well-built engine4 ,in order to prevent a too rapid wear of the cylinder1 several ,german manufacturers finish off the front of the piston with bronze or anti-friction metal in engines of more than #dj to #ej horse-power4 ,it is to be observed1 however1 that this expedient is not applicable to motors the cylinders of which are comparatively cold2 otherwise the bronze or anti-friction metal will deteriorate4 ,arrangement of the ,cylinder4--,the cylinder shell or liner1 in which the piston travels1 and the water-jacket should preferably be made in separate pieces and not cast of the same metal1 in order to permit a free expansion 7,figs4 #bb and #bc74 ,if for want of care or of proper lubrication1 which frequently occurs in gas-engines1 the cylinder should be injured by grinding1 it can be easily renewed1 without the loss of all the connecting parts4 ,illustration3 ,,fig4 #bb4--;,head1 jacket and liner of cylinder1 cast in one piece4 ,illustration3 ,,fig4 #bc4--;,cylinder with independent liner and head4 ,for the same reason1 the cylinder and its casing should be independent of the frame4 ,in many horizontal engines1 the cylinders overhang the frame throughout the entire length1 by reason of the joining of their front portions with the frames4 ,although such a construction is attended with no serious consequences in small engines1 nevertheless in large engines it is exceedingly harmful4 ,indeed1 in most modern single-acting engines1 the pistons are directly connected with the crank-shaft by the piston-rod1 without any intermediate connecting-rod or cross-head4 ,the vertical reaction of the motive effort on the piston is1 therefore1 taken up entirely by the thrust of the cylinder1 which is also vertical 7,fig4 #bd74 ,this thrust1 acting against an unsupported part1 may cause fractures2 at any rate1 it entails a rapid deterioration of the cylinder joint4 ,illustration3 ,,fig4 #bd4--,single-acting engines4 ,illustration3 ,,fig4 #be4--;,engine with inclined bearings4 ,the ,frame4--,gas-engines driven as they are1 by explosions1 giving rise to shocks and blows1 should be built with frames1 heavy1 substantial1 and broad-based1 so as to rest solidly on the ground4 ,this essential condition is often fulfilled at the cost of the engine's appearance2 but appearance will be willingly sacrificed to meet one of the requirements of perfect operation4 ,for engines of more than #h to #aj horse-power1 frames should be employed which can be secured to the masonry foundation without a separate pedestal or base4 ,some manufacturers1 for the purpose of lightening the frame1 attach but little importance to the foundation and to strength of construction1 and employ the design illustrated in place of the crank-shaft bearing 7,fig4 #be72 others1 in order to facilitate the adjusting of the connecting-rod bearings1 prefer the second form 7,fig4 #bf74 ,it is evident that1 in the first case1 a part of the effort produced by the explosion reacts on the upper portion of the connecting-rod bearing1 on the cap of the crank-shaft bearing1 and consequently on the fastening-bolts4 ,in the second case1 if the adjustment be not very carefully made1 or if the rubbing surfaces are insufficient1 the entire thrust due to the explosion will be received by the meeting parts of the two bushings1 thus injuring them and causing a more rapid wear4 ,in the construction of large engines1 some manufacturers take the precaution of forming the connecting-rod bearings of four parts1 adjustable to take up the wear1 so that the effort is exerted against the parts disposed at right angles to each other4 ,a form that seems rational is that shown in ,fig4 #bg1 in which the reaction of the thrust is taken up by the lower bearing1 rigidly supported by the braced frame1 in the direction opposite to that of the explosive effort4 ,illustration3 ,,fig4 #bf4--;,engine with straight bearings4 ,illustration3 ,,fig4 #bg4--;,engine with correctly designed bearings4 ,the sum of the projecting surfaces of the two bearings should be so calculated that a maximum explosive pressure of #dje to #dbe pounds per square inch will not subject the bearings to a pressure higher than #dbe to #eej pounds per square inch4 ,fly-,wheels4--,in gas-engines particularly1 the fly-wheel should be secured to the crank-shaft with the utmost care4 ,it should be mounted as near as possible to the bearings2 otherwise the alinement of the shaft will be destroyed and its strength impaired4 ,if the fly-wheel be fastened by means of a key or wedge having a projecting head1 it is advisable to cover the end of the shaft by a movable sleeve4 ,the fly-wheel should run absolutely true and straight even if the explosion be premature4 ,in well-built engines the fly-wheels are lined up and shaped to the rim4 ,the periphery is slightly rounded in order the better to guide the belt when applied to the wheel4 ,illustration3 ,,fig4 #bh4--,single fly-wheel engine with external bearing4 ,furthermore1 fly-wheels should be nicely balanced2 those are to be preferred which have no counter-weights cast or fastened to the hub1 the spokes1 or the rim4 ,the system of balancing the engine by means of two fly-wheels1 mounted on opposite sides1 is used chiefly for the purpose of equalizing the inertia effects4 ,special engines1 employed for driving dynamos1 and even industrial engines of high power1 are preferably fitted with but a single fly-wheel1 with an outer bearing1 since they more readily counteract the cyclic irregularities or variations of speed occurring in a single revolution 7,fig4 #bh74 ,if in this case a pulley be provided1 it should be mounted between the engine and the outer bearing4 ,the following advantages may be cited in favor of the single fly-wheel1 particularly in the case of dynamo-driving engines3 #a4 ,the single fly-wheel permits a more ready access to the parts to be examined4 #b4 ,it involves the employment of a third bearing1 thus avoiding the overhang caused by two ordinary fly-wheels4 #c4 ,it avoids the torsional strain to which the two-wheel crank is subjected when starting1 stopping1 and changing the load1 the peripheral resistance varying in one of the fly-wheels1 while the other is subjected to a strain in the opposite direction on account of the inertia4 #d4 ,two fly-wheels1 keyed as they are to projecting ends of the shaft1 will be so affected at the rims by the explosions that the belts will shake4 ,the third bearing which characterizes the single-fly-wheel system1 is but an independent support1 resting solidly on the masonry bed of the engine4 ,the bearing with its independent support is sufficiently rigid1 and is not subjected to any stress from the crank at the moment of explosion1 the reaction of the crank affecting only the frame bearings4 ,with such fly-wheels1 reputable firms guarantee a cyclic regularity which compares favorably with that of the best steam-engines4 ,for a duty varying from a third of the load to the maximum load1 these engines1 when driving direct-current dynamos for directly supplying an electric-light circuit1 will insure perfect steadiness of the light2 and the effectually aperiodic measuring instruments will not indicate fluctuations greater than #b to #c per cent4 of the tension or intensity of the current4 ,the coefficient of the variations in the speed of a single revolution will thus be not far from #a_/fj4 ,illustration3 ,,fig4 #bi4--;,curved spoke fly-wheel4 ,straight and ,curved ,spoke ,fly-,wheels4--,the spokes of fly-wheels are either straight or curved4 ,in assembling the motor parts it too often occurs that curved spoke fly-wheels are mounted with utter disregard of the direction in which they are to turn4 ,it is important that curved spokes should be subjected to compression and not to traction4 ,hence the fly-wheels should be so mounted that the concave portions of the spokes travel in the direction of rotation1 as shown in the accompanying diagram 7,fig4 #bi74 ,if a single fly-wheel be employed on an engine of the type in which the speed is governed by the hit-and-miss system1 the fly-wheel should be extra heavy to counteract the irregularities of the motive impulses when the engine is not working at its full load1 or in other words1 when no explosion takes place at every cycle4 ,illustration3 ,,fig4 #cj4--;,forged crank-shafts4 ,the ,crank-,shaft4--,the crank-shaft should be made of the best mild steel4 ,those shafts are to be preferred the cranks of which are not forged on 7,fig4 #cj71 but cut out of the mass of metal2 furthermore1 the brackets or supports should be planed and shaped so that they are square in cross-section4 ,illustration3 ,,fig4 #ca4--;,correct design of crank-shaft4 ,such a design involves fine workmanship and speaks well for the construction of the whole engine4 ,moreover1 it enables the bearings to be brought nearer each other1 reduces to a minimum that part of the crank-shaft which may be considered the weakest1 and permits a rational and exact counterbalancing of the moving parts1 such as the crank and the end of the connecting-rod4 ,the best manufacturers have adopted the method of fastening to the cranks balancing weights secured to the brackets1 especially for high-speed engines or for engines of high power4 ,the projecting surface of the crank-pin should1 as a rule1 be calculated for a pressure of #a1djj pounds per square inch4 ,illustration3 ,,fig4 #cb4--;,crank-shaft with balancing weight4 ,cams1 ,rollers1 etc4--,the cams1 rollers1 thrust-bearings1 as well as the piston-pin in particular1 should be made of good steel1 case-hardened to a depth of at least 4#jh of an inch4 ,their hardness and the degree of cementation may be tested by means of a file4 ,this is the method followed by the best manufacturers4 ,bearings4--,all the bearings and all guides should be adjustable to take up the wear4 ,they are usually made of bronze or of the best anti-friction metal4 ,steadiness4--,the steadiness of engines may be considered from two different standpoints4 ,illustration3 ,,fig4 #cc4--;,inertia governor4 #a4 ,variation of the ,number of ,revolutions at ,different ,loads4--,this depends chiefly on the sensitiveness of the governor1 which should be of the inertia or of the ball 7or centrifugal7 type4 ,the first form is rarely employed1 except in small engines up to #aj horse-power1 and is applicable only to engines in which the hit and miss system is employed 7,fig4 #cc74 ,the second form is more widely used1 and is applicable to engines having hit-and-miss or variable admission devices4 ,in the first form1 the governor simply displaces a very light member1 whatever may be the size of the engine1 for which reason the dimensions are very small4 ,in the second form1 on the other hand1 the governor acts either on a conical sleeve or on some other regulating member offering resistance4 ,evidently1 in order to overcome the reactions to which it is subjected1 it must be as heavy and powerful as a steam-engine governor4 ,sufficient allowance is made in a good engine for variation in the number of revolutions between no load and full load1 not greater than two per cent4 if the admission be of the hit-and-miss type1 and five per cent4 if it be of the variable type4 #b4 ,cyclic ,regularity4--,this term means simply that the speed of the engine is constant in a single revolution4 ,in practice this is never attained4 ,allowance is made in engines used for driving direct-current dynamos for a variation of about #a_/fj2 while in industrial engines a variation of #a_/be is permissible4 ,cyclic variation depends only on the weight of the fly-wheel2 whereas variation in the number of revolutions is determined chiefly by the governor4 ,governors4--,diagrams are here presented of the principal types of governors--the inertia governor1 the ball or centrifugal governor controlling an admission-valve of the hit-and-miss type 7,fig4 #cd71 and the ball or centrifugal governor controlling a variable gas-admission valve 7,fig4 #ce74 ,in distinguishing between the operation of the two last-mentioned types1 it may be stated that the former bears the same relation to the hit-and-miss gear as it does1 for example1 to the valve gear of a ,corliss steam-engine4 ,in other words1 it is an apparatus that indicates without inducing1 admission or cut-off4 ,the second type1 on the other hand1 operates by means of slides and the like1 as in the ,ridder type of engine1 in which it controls the displacement of the cut-off or distribution slide-valve and is subjected to variable forces1 depending on the pressure1 lubrication1 the condition of the stuffing-boxes1 and the like4 ,in gas as well as in steam engines1 designs are to be commended which shield the delicate mechanism from strains and stresses that are likely to destroy its sensitiveness1 as is the case in the automatic cut-off of the ,corliss steam-engine4 ,illustration3 ,,fig4 #cd4--;,hit-and-miss governor4 ,governors should be provided with means to permit the manual variation of the speed while the engine is in operation4 ,for small motors1 one of the most widely used admission devices is that of the hit-and-miss type4 ,as its name indicates1 this admission arrangement allows a given quantity of gas to enter the cylinder for a number of consecutive intervals1 until the engine is about to exceed its normal speed4 ,thereupon the governor cuts off the gas entirely4 ,the result is that1 in this system1 the number of admissions is variable1 but that each admitted charge is composed of a constant proportion of gas and air4 ,the governors employed for the hit-and-miss type are either inertia or centrifugal governors4 ,inertia governors 7,fig4 #cc7 are less sensitive than those of the centrifugal type4 ,they are generally applied only to industrial engines of small power1 in which regularity of operation is a secondary consideration4 ,centrifugal governors employed for gas-engines with hit-and-miss regulation are1 as a general rule1 noteworthy for their small size1 which is accounted for by the fact that1 in most systems1 merely a movable member is placed between the admission-controlling means and the valve-stem 7,fig4 #cd74 ,it follows that this method of operation relieves the governor of the necessity of overcoming the resistance of the weight of moving parts1 more or less effectually lubricated1 and subjected to the reaction of the parts which they control4 ,in engines equipped with variable admission devices for the gas or the explosive mixture1 the governor actuates a sleeve on which the admission-cam is fastened 7,fig4 #ce74 ,or1 the governor may displace a conical cam1 the reaction of which1 on contact with the lever1 destroys the stability of the governor4 ,these conditions justify the employment of powerful governors which1 on account of the inertia of their parts1 diminish the reactionary forces encountered4 ,the centrifugal governor should be sufficiently effectual to prevent variations in the number of revolutions within the limits of #b to #c per cent4 between no load and approximately full load4 ,under equivalent conditions1 the inertia governor can hardly be relied upon for a coefficient of regularity greater than #d to #e per cent4 ,illustration3 ,,fig4 #ce4--,variable admission governor4 ,the manner of a governor's operation is necessarily dependent on the admission system adopted4 ,and the admission system varies essentially with the size1 the purpose of the engine1 and the character of the fuel employed4 ,illustration3 ,,fig4 #cf4--,vertical engine4 ,illustration3 ,,fig4 #cg4--,section through an engine of the vertical or steam-hammer type4 ,vertical ,engines4--,for some years past there seems to have been a tendency in ,europe to use horizontal instead of vertical engines1 especially since engines of more than #aj or #ae horse-power have been extensively used for industrial purposes4 ,the vertical type is used for #a to #h horse-power engines1 with the cylinder in the lower part of the frame1 and the shaft and its fly-wheel in the upper part 7,fig4 #cf74 ,the only merit to be attributed to this arrangement is a great saving of space4 ,it is evident1 however1 that beyond a certain size and power1 such engines are unstable4 ,in ,america particularly1 many manufacturers of high-power engines 7#ej to #ajj horse-power or more7 prefer the vertical or steam-hammer arrangement1 which consists in placing the cylinder in the upper part1 and the shaft in the lower part of the frame as close to the ground as possible 7,figs4 #cg and #ch74 ,the problem of saving space1 as well as that of insuring stability1 is thus solved1 so that it is easily possible to run up the speed of the engine4 ,there is also the advantage that the shaft of a dynamo can be directly coupled up with the crank-shaft of the engine1 thus dispensing with a belt1 which1 at the least1 absorbs #d to #f per cent4 of the total power4 ,it should1 nevertheless1 be borne in mind that the direct coupling of electric generators to engine-shafts implies the use of extremely large and1 therefore1 of extremely costly dynamos4 ,furthermore1 by reason of this arrangement1 groups of electro-generators can be disposed in a comparatively small amount of space4 ,some ,english manufacturers are also beginning to adopt the steam-hammer type of engine for high powers1 the result being a marked saving in material and lowering of the cost of installation4 ,illustration3 ,,fig4 #ch4--,side and end elevations of a vertical or steam-hammer engine4 ,power of the ,engine4--,the first thing to be considered is that the power of a gas-engine is always given in effective horse-power1 and that the power of a steam-engine is always given in indicated horse-power in contracts of sale4 ,in ,england and in the ,united ,states1 the expression nominal horse-power is still employed4 ,it may be advisable to define these various terms exactly1 since unscrupulous dealers1 to the buyer's loss1 have done much to confuse them4 ,indicated horse-power is a designation applied to the theoretical power produced by the action of the motive agent on the piston4 ,the work performed is measured on an indicator card1 by means of which the average pressure to be considered in the computation of the theoretical power is ascertained4 ,the effective or brake horse-power is equal to the indicated horse-power1 less the energy absorbed by passive resistance1 friction of the moving parts1 etc4 ,the effective work is an experimental term applied to the power actually developed at the shaft4 ,this work is of interest solely to the engine user4 ,in a well-built motor1 in which the passive resistance by reason of the correct adjustment and simplicity of the parts1 is reduced to a minimum1 the effective horse-power is about #hj to #hg per cent4 of the indicated horse-power1 when the engine runs under full load4 ,this reduced output is usually called the mechanical efficiency of the engine4 ,nominal horse-power is an arbitrary term in the sense in which it is used in ,england and ,america1 where it is quite common4 ,the manufacturers themselves do not seem to agree on its absolute value4 ,a nominal horse-power1 however1 is equal to anything from #c to #d effective horse-power4 ,the uncertainty which ensues from the use of the term should lead to its abandonment4 ,in installing a motor1 the determination of its horse-power is a matter of grave importance1 which should not be considered as if the motor were a steam-engine or an engine of some other type4 ,it must not be forgotten that1 especially at full load1 explosion-engines are most efficient1 and that1 under these conditions1 it will generally be advisable to subordinate the utility of having a reserve power to the economy which follows from the employment of a motor running at a load close to its maximum capacity4 ,on the other hand1 the gas-engine user is unwilling to believe that the stipulated horse-power of the motor which is sold to him is the greatest that it is capable of developing under industrial conditions4 ,business competition has led some firms to sell their engines to meet these conditions4 ,it is probably not stretching the truth too far to declare that #hj per cent4 of the engines sold with no exact contract specifications are incapable of maintaining for more than a half hour the power which is attributed to them1 and which the buyer expects4 ,it follows that the power at which the engine is sold should be both industrially realized and maintained1 if need be1 for an entire day1 without the engine's showing the slightest perturbation1 or faltering in its silent and regular operation4 ,to attain this end1 it is essential that the energy developed by the engine in normal or constant operation should not exceed #ij to #ie per cent4 of the maximum power which it is able to yield1 and which may be termed its utmost power4 ,as a general rule1 especially for installations in which the power fluctuates from the lowest possible to double this1 as much attention must be paid to the consumption at half load as at full load2 and preference should be given to the engine which1 other things being equal1 will operate most economically at its lowest load4 ,in this case the consumption per effective horse-power is appreciably higher4 ,generally1 this consumption is greater by #bj to #cj per cent4 than that at full load4 ,this is particularly true of the single-acting engines so widely used for horse-powers less than #ajj to #aej4 ,in some double or triple-acting engines1 according to certain writers1 the diminution in the consumption will hardly be proportional to the diminution of the power1 or at any rate1 the difference between the consumption per ,b4,h4,p4 at full load and at reduced load will be less than in other engines4 ,it should be observed1 however1 that this statement is apparently not borne out by experiments which the author has had occasion to make4 ,to a slight degree1 this economy is obtained at the cost of simplicity1 and consequently1 at the cost of the engine4 ,at all events1 the engines have the merit of great cyclic regularity1 rendering them serviceable for driving electric-light dynamos2 but this regularity can also be attained by the use of the extra heavy fly-wheels which ,english firms1 in particular1 have introduced4 ,automatic ,starting4--,when the gas-engine was first introduced1 starting was effected simply by manually turning the fly-wheel until steady running was assured4 ,this procedure1 altogether too crude in its way1 is attended with some danger4 ,in a few countries it is prohibited by laws regulating the employment of industrial machinery4 ,if the engine be of rather large size one1 moreover1 which operates at high pressure--such a method of starting is very troublesome4 ,for these reasons1 among others1 manufacturers have devised automatic means of setting a gas-engine in motion4 ,of such automatic devices1 the first that shall be mentioned is a combination of pipes1 provided with cocks1 by the manipulation of which1 a certain amount of gas1 drawn from the supply pipe1 is introduced into the engine-cylinder4 ,the piston is first placed in a suitable position1 and behind it a mixture is formed which is ignited by a naked flame situated near a convenient orifice4 ,when the explosion takes place the ignition-orifice is automatically closed1 and the piston is given its motive impulse4 ,the engine thus started continues to run in accordance with the regular recurrence of the cycles4 ,in this system1 starting is effected by the explosion of a mixture1 without previous compression4 ,some designers have devised a system of hand-pumps which compress in the cylinder a mixture of air and gas1 ignited at the proper time by allowing it to come into contact with the igniter1 through the manipulation of cocks 7,fig4 #ci74 ,these two methods are not absolutely effective4 ,they require a certain deftness which can be acquired only after some practice4 ,furthermore1 they are objectionable because the starting is effected too violently1 and because the instantaneous explosion subjects the stationary piston1 crank1 and fly-wheel to a shock so sudden that they may be severely strained and may even break4 ,moreover1 the slightest leakage in one of the valves or checks may cause the entire system to fail1 and1 particularly in the case of the pump1 may induce a back explosion exceedingly dangerous to the man in charge of the engine4 ,these systems are now almost generally supplanted by the compressed-air system1 which is simpler1 less dangerous1 and more certain in its effect4 ,the elements comprising the system in question include essentially a reservoir of thick sheet iron1 capable of resisting a pressure of #ahj to #bbe pounds and sufficient in capacity to start an engine several times4 ,this reservoir is connected with the engine by piping1 which is disposed in one of two ways1 depending upon whether the reservoir is charged by the engine itself operatively connected with the compressor1 or by an independent compressor1 mechanically operated4 ,illustration3 ,,fig4 #ci4--,tangye starter4 ,in the first case1 the pipe is provided with a stop-cock1 mounted adjacent to the cylinder1 and with a check-valve4 ,when the engine is started and the gas cut off1 the air is drawn in at each cycle and driven back into the reservoir during the period of compression4 ,when the engine1 running under these conditions by reason of the inertia of the fly-wheel1 begins to slow down1 the check-valve is closed and the gas-admission valve opened1 so as to produce several explosions and to impart a certain speed to the engine in order to continue the charging of the reservoir with compressed air4 ,this done1 the valve on the reservoir itself is tightly closed1 as well as the check-valve1 so as to avoid any leakage likely to cause a fall in the reservoir's pressure4 ,in the second case1 which applies particularly to engines of more than #ej horse-power1 the charging pipe connected with the reservoir is necessarily independent of the pipe by means of which the motor is started4 ,the reservoir having been filled and the decompression cam thrown into gear1 starting is accomplished3 #a4 ,by placing the piston in starting position1 which corresponds with a crank inclination of #aj to #bj degrees in the direction of the piston's movement1 from the rear dead center1 immediately after the period of compression2 #b4 ,by opening the reservoir-valve2 #c4 ,by allowing the compressed air to enter the cylinder rapidly1 through the quick manipulation of the stop-cock1 which is closed again when the impulse is given and reopened at the corresponding period of the following cycle1 this operation being repeated several times in order to impart sufficient speed to the motor2 #d4 ,by opening the gas-valve and finally closing the two valves of the compressed-air pipe4 ,the pipes and compressed-air reservoirs should be perfectly tight4 ,the reservoirs should have a capacity in inverse ratio to the pressure under which they are placed1 i4e41 they increase in size as the pressure decreases4 ,if1 for example1 the reservoirs should be operated normally at a pressure of #aje to #abj pounds per square inch1 their capacity should be at least five or six times the volume of the engine-cylinder4 ,if these reservoirs are charged by the engine itself1 the pressure will always be less by #ae to #bj per cent4 than that of the compression4 ,,chapter ,,iii ,,the ,,installation ,,of ,,an ,,engine ,in the preceding chapter the various structural details of an engine have been summarized and those arrangements indicated which1 from a general standpoint1 seem most commendable4 ,no particular system has been described in order that this manual might be kept within proper limits4 ,moreover1 the best-known writers1 such as ,hutton1 ,hiscox1 ,parsell and ,weed1 in ,america2 ,aime ,witz1 in ,france2 ,dugald ,clerk1 ,frederick ,grover1 and the late ,bryan ,donkin1 in ,england2 ,gueldner1 ,schottler1 ,thering1 in ,germany1 have published very full descriptive works on the various types of engines4 ,we shall now consider the various methods which seem preferable in installing an engine4 ,the directions to be given1 the author believes1 have not been hitherto published in any work1 and are here formulated1 after an experience of fifteen years1 acquired in testing over #djj engines of all kinds1 and in studying the methods of the leading gas-engine-building firms in the chief industrial centers of ,europe and ,america4 ,location4--,the engine should be preferably located in a well-lighted place1 accessible for inspection and maintenance1 and should be kept entirely free from dust4 ,as a general rule1 the engine space should be enclosed4 ,an engine should not be located in a cellar1 on a damp floor1 or in badly illuminated and ventilated places4 ,gas-,pipes4--,the pipes by which fuel is conducted to engines1 driven by street-gas1 and the gas-bags1 etc41 are rarely altogether free from leakage4 ,for this reason1 the engine-room should be as well ventilated as possible in the interest of safety4 ,long lines of pipe between the meter and the engine should be avoided1 for the sake of economy1 since the chances for leakage increase with the length of the pipe4 ,it seldom happens that the leakage of a pipe #cj to #ej feet long1 supplying a #cj horse-power engine1 is much less than #ij cubic feet per hour4 ,the beneficial effect of short supply pipes between meter and engine on the running of the engine is another point to be kept in mind4 ,an engine should be supplied with gas as cool as possible1 which condition is seldom realized if long pipe lines be employed1 extending through workshops1 the temperature of which is usually higher than that of underground piping4 ,on the other hand1 pipes should not be exposed to the freezing temperature of winter1 since the frost formed within the pipe1 and particularly the crystalline deposition of naphthaline1 reduces the cross section and sometimes clogs the passage4 ,often it happens that water condenses in the pipes2 consequently1 the piping should be disposed so as to obviate inclines1 in which the water can collect in pockets4 ,an accumulation of water is usually manifested by fluctuations in the flame of the burner4 ,in places where water can collect1 a drain-cock should be inserted4 ,in places exposed to frost1 a cock or a plug should be provided1 so that a liquid can be introduced to dissolve the naphthaline4 ,to insure the perfect operation of the engine1 as well as to avoid fluctuations in nearby lights1 pipes having a large diameter should preferably be employed4 ,the cross-section should not be less than that of the discharge-pipe of the meter1 selected in accordance with the prescriptions of the following table3 ,,gas-,,meters4 ,table ,headings-- ,column ,a3 ,capacity4 ,column ,b3 ,normal hourly flow4 ,column ,c3 ,height4 ,column ,d3 ,width4 ,column ,e3 ,depth4 ,column ,f3 ,diameter of pipe4 ,column ,g3 ,power of engine to be fed4 ,dimension in inches4 ,a4 ,b4 ,c4 ,d4 ,e4 ,f4 ,g4 burners cu4 ft4 h4-p4 #c #ad4gbf #ac #aa #i-ac_/af #j4eij #a_/b #e #bd4gaj #ah #ac-c_/d #aj-e_/h #j4ghg #c_/d #aj #di4dbj #ba-a_/d #ah-a_/b #ab-i_/af #j4ihd #a-b #bj #ih4hdj #bc-c_/af #ai-aa_/af #ae-e_/af #a4aha #c-d #cj #adh4bfj #be-e_/h #ba-aa_/af #ah-c_/af #a4def #e-f #ej #bdg4ajj #bi-a_/b #bd-e_/af #bj-g_/af #a4eib #g-aj #fj #bif4ebj #cj-e_/af #be-e_/h #be-e_/h #a4fga #aa-ad #hj #cie4cfj #cc-e_/af #cj-e_/af #bg-a_/h #a4ifh #ae-ai #ajj #did4bjj #ce #cc-g_/af #bi-ae_/af #a4ifh #bj-be #aej #gda4cjj #dj-c_/af #dj-c_/af #cc-ac_/af #cj-dj ,the records made are exact only when the meters 7,fig4 #dj7 are installed and operated under normal conditions4 ,two chief causes tend to falsify the measurements in wet meters3 7#a7 evaporation of the water1 7#b7 the failure to have the meter level4 ,evaporation occurs incessantly1 owing to the flowing of the gas through the apparatus1 and increases with a rise in the temperature of the atmosphere surrounding the meter4 ,consequently this temperature must be kept down1 for which reason the meter should be placed as near the ground as possible4 ,the evaporation also increases with the volume of gas delivered4 ,hence the meter should not supply more than the volume for which it was intended4 ,in order to facilitate the return of the water of condensation to the meter and to prevent its accumulation1 the pipes should be inclined as far as possible toward the meter4 ,the lowering of the water-level in the meter benefits the consumer at the expense of the gas company4 ,illustration3 ,,fig4 #dj4--,wet gas-meter4 ,inclination from the horizontal has an effect that varies with the direction of inclination4 ,if the meter be inclined forward1 or from left to right1 the water can flow out by the lateral opening at the level1 and incorrect measurements are made to the consumer's cost4 ,during winter1 the meter should be protected from cold4 ,the simplest way to accomplish this1 is to wrap substances around the meter which are poor conductors of heat1 such as straw1 hay1 rags1 cotton1 and the like4 ,freezing of the water can also be prevented by the addition of alcohol in the proportion of #b pints per burner4 ,the water is thus enabled to withstand a temperature of about #e degrees ,f4 below zero4 ,instead of alcohol1 glycerine in the same proportions can be employed1 care being taken that the glycerine is neutral1 in order that the meter may not be attacked by the acids which the liquid sometimes contains4 ,illustration3 ,,fig4 #da4--;,dry gas-meter4 ,dry ,meters4--,dry meters are employed chiefly in cold climates1 where wet meters could be protected only with difficulty and where the water is likely to freeze4 ,in the ,united ,states the dry meter is the type most widely employed4 ,in ,sweden and in ,holland it is also generally introduced 7,fig4 #da74 ,in the matter of accuracy of measurement there is little1 if any1 difference between wet and dry meters4 ,the dry meter has the merit of measuring correctly regardless of the fluctuations in the water level4 ,on the other hand1 it is open to the objection of absorbing somewhat more pressure than the wet meter1 after having been in operation for a certain length of time4 ,this is an objection of no great weight2 for there is always enough pressure in the mains and pipes to operate a meter4 ,illustration3 ,,fig4 #db4--,section through a dry gas-meter4 ,in many cases1 where the employment of non-freezing liquids is necessary1 the dry meter may be used to advantage1 since all such liquids have more or less corroding effect on sheet lead and even tin1 depending upon the composition of the gas4 ,illustration3 ,,fig4 #dc4--,section through a dry gas-meter4 ,the dry meter comprises two bellows1 operating in a casing divided into two compartments by a central partition4 ,the gas is distributed on one or the other side of the bellows1 by slides ,b4 ,the slides ,b are provided with cranks ,e1 controlled by levers ,m1 actuated by transmission shafts ,o1 driven by the bellows4 ,the meter is adjusted by a screw which changes the throw of the cranks ,e and consequently affects the bellows4 ,the movement of the crank-shaft ,d is transmitted to the indicating apparatus4 ,in order to obviate any leakage1 this shaft passes through a stuffing-box1 ,g4 ,the diagrams 7,figs4 #db-dc7 show the construction of a dry meter1 the arrows indicating the course taken by the gas4 ,illustration3 ,,fig4 #dd4--,rubber bag to prevent fluctuations of the ignition flame4 ,illustration3 ,,fig4 #de4--,rubber bags on gas-pipes4 ,care should be taken to provide the gas-pipe with a drain-cock1 at a point near the engine4 ,by means of this cock1 any air in the pipe can be allowed to escape before starting2 otherwise the engine can be set in motion only with difficulty4 ,if the engine be provided with an incandescent tube1 the gas-supply pipe of the igniter should be fitted with a small rubber pouch or bag1 in order to obviate fluctuations in the burner flame1 caused by variations in the pressure 7,fig4 #dd74 ,as a general rule1 the supply-pipe should be connected with the main pipe on the forward side of the bags and gas-governors4 ,the main pipe and all other piping near the engine should extend underground1 so that free access to the motor from all sides can be obtained1 without possibility of injury4 ,anti-pulsators1 ,bags1 ,pressure-,regulators4--,the most commonly employed means of preventing fluctuation of nearby lights1 due to the sharp strokes of the engine1 consists in providing the gas-supply pipe with rubber bags 7,fig4 #de71 which form reservoirs for the gas and1 by reason of their elasticity1 counteract the effect produced by the suction of the engine4 ,nevertheless1 in order to insure a supply of gas at a constant pressure1 which is necessary for the perfect operation of the engine1 there are generally used1 in addition to the bags1 devices called gas-governors1 or anti-pulsators 7,fig4 #df74 ,although these devices are constructed in different ways1 the underlying principle is the same in all4 ,they comprise a metallic casing1 containing a flexible diaphragm of rubber or of some fabric impermeable to gas4 ,suction of the engine creates a vacuum in the casing4 ,the diaphragm bends1 thereby actuating a valve1 which cuts off the gas supply4 ,during the three following periods 7compression1 explosion1 and exhaust7 the gas1 by reason of its pressure on the diaphragm1 opens the valve and fills the casing1 ready for the next suction stroke4 ,illustration3 ,,fig4 #df4--;,an anti-pulsator4 ,other devices1 which are never sold with the engine1 but are rendered necessary by reason of the conditions imposed by the gas supply are sold under the name pressure-regulators 7,fig4 #dg74 ,they consist of a bell1 floating in a reservoir containing water and glycerine 7or mercury71 and likewise actuate a valve which partially controls the flow of gas4 ,this valve being balanced1 its mechanical action is the more certain4 ,such devices are very effective in maintaining the steadiness of lights4 ,on the other hand1 they are often an obstacle to the operation of the engine because they reduce the flow and pressure of the gas too much4 ,in order to obviate this difficulty1 a pressure-regulator should be chosen with discrimination1 and of sufficiently large size to insure the maintenance of an adequate supply of gas to the engine4 ,frequent examinations should be made to ascertain if the bell of the regulator is immersed in the liquid4 ,in the case of anti-pulsators1 care should be taken that they are not spattered with oil1 which has a disastrous effect on rubber4 ,anti-pulsators are generally mounted about #d inches from a wall1 in order that the diaphragm may be actuated by hand1 if need be4 ,illustration3 ,,fig4 #dg4--;,a pressure-regulator4 ,precautions4--,in order not to strain the rubber of the bags or of the anti-pulsators1 it is advisable to place a stop-cock in advance of these devices so that they can not be filled while the motor is at rest4 ,the capacity of the rubber bags that can be bought in the market being limited1 it is necessary to place one1 two1 or three extra bags in series 7,figs4 #dh and #di71 for large pipes2 but it should be borne in mind that the total section of the branch pipes should be at least equal to that of the main pipe4 ,it is also advisable to extend the tube completely through the bag as shown in ,figs4 #dh and #di4 ,illustration3 ,,figs4 #dh-di4--;,arrangement of rubber bags4 ,if there be two branch pipes the minimum diameter which meets this requirement is ascertained as follows3 ,draw to any scale a semicircle having a diameter equal or proportional to that of the main pipe 7,fig4 #ej74 ,the sides of the isosceles triangle inscribed within this semicircle give the minimum diameter of each of the branch pipes4 ,sometimes engines are provided with a cock having an arrangement by means of which the gas feed is permanently regulated1 according to the quality and pressure of the gas and according to the load at which the engine is to run4 ,this renders it possible to open the cock always to the same point 7,fig4 #ea74 ,illustration3 ,,fig4 #ej4 ,illustration3 ,,fig4 #ea4 ,air ,suction4--,in a special chapter the precautions to be taken to counteract the influence of the suction of the engine in causing vibration will be treated4 ,the manner in which the suction of air is effected necessarily has as marked an influence on the operation of the engine as the supply of gas1 since air and gas constitute the explosive mixture4 ,resistance to the suction of air should be carefully avoided1 for which reason the length of the pipe should be reduced to a minimum1 and its cross-section kept at least equal to that of the air inlet of the engine4 ,since the quality of street-gas varies with each city1 the proper proportions of gas and air are not constant4 ,in order that these proportions may be regulated1 it is a matter of some importance to fit some suitable device on the pipe4 ,good engines are provided with a plug or flap valve4 ,generally the air-pipe terminates either in the hollowed portion of the frame1 or in an independent pot1 or air chest4 ,the first arrangement is not to be recommended for engines over #bj to #be horse-power4 ,accidents may result1 such as the breaking of the frame by reason of back firing1 of which more will be said later4 ,if an independent chest be employed1 its closeness to the ground renders it possible for dust easily to pass through the air-holes in the walls at the moment of suction1 and even to enter the cylinder1 where its presence is particularly harmful1 leading1 as it does1 to the rapid wear of the rubbing surfaces4 ,this evil can be largely remedied by filling the air-chest with cocoa fiber or even wood fiber1 provided the latter does not become packed down so as to prevent the air from passing freely4 ,such fibers act as air-filters4 ,regular cleaning or renewal of the fiber protects the cylinder from wear4 ,in a general way1 care should be taken1 before fitting both the gas and air pipes1 to tap the pipes1 elbows1 and joints lightly with a hammer on the outside in order to loosen whatever rust or sand may cling to the interior2 otherwise this foreign matter may enter the cylinder and cause perturbations in the operation of the engine4 ,under all circumstances1 care should be taken not to place the end of the air-pipe under the floor or in an enclosed space1 because leakage may occur1 due to the bad seating of the air-valve1 thereby producing a mixture which may explode if the flame leaps back1 as we shall see in the discussion of suction by pipes terminating in the hollow of the frame4 ,on the other hand1 sand or sawdust should not be sprinkled on the floor4 ,exhaust4--,for the exhaust1 cast-iron or drawn pipes as short as possible should be used4 ,not only the power of the engine1 but also its economic consumption1 can be markedly affected by the employment of long and bent pipes4 ,resistance to the exhaust of the products of combustion not only causes an injurious counter-pressure1 but also prevents the clearing of the cylinder of burnt gases1 which contaminate the aspired mixture and rob it of much of its explosiveness4 ,the necessity of evacuating the cylinder as completely as possible is1 nevertheless1 not always reconcilable with local surroundings4 ,to a certain extent1 the objections to long exhaust-pipes are overcome by rigorously avoiding the use of elbows4 ,gradual curves are preferable4 ,in the case of very long pipes it is advisable to increase their diameter every #af feet from the exhaust4 ,the exhaust-chest should be placed as near as possible to the engine2 it should never be buried2 for the joints of the inlet and outlet pipes of the exhaust-chest should be easily accessible1 so that they may be renewed when necessary4 ,the author recommends the placing of the exhaust-chest in a masonry pit1 which can be closed with a sheet-metal cover4 ,for engines of #bj horse-power and upward1 these joints should be entirely of asbestos4 ,pipes screwed directly into the casting are liable to rust4 ,exposed as they are to the steam or water of the exhaust1 they cannot be detached4 ,illustration3 ,,fig4 #eb4--,method of mounting pipes4 ,the water1 which results from the combination of the hydrogen of the gas with the oxygen of the air1 is deposited in most cases at the bottom of the exhaust-chest4 ,it is advisable to fit a plug or iron cock in the base of the chest4 ,alkaline or acid water will always corrode a bronze cock4 ,in order that the pipes may not also be attacked1 they are not disposed horizontally1 but are given a slight incline toward the point where the water is drained off4 ,if pipes of some length be employed1 they should be able to expand freely without straining the joints1 as shown in the accompanying diagram 7,fig4 #eb71 in which the exhaust-chest rests on iron rollers which permit a slight displacement4 ,for the sake of safety1 at least that portion of the piping which is near the engine should be located at a proper distance from woodwork and other combustible material4 ,by no means should the exhaust discharge into a sewer or chimney1 even though the sewer or chimney be not in use2 for the unburnt gases may be trapped1 and dangerous explosions may ensue at the moment of discharge4 ,the joints or threaded sleeves employed in assembling the exhaust-pipe should be tested for tightness4 ,the combined action of the moisture and heat causes the metal to rust and to deteriorate very rapidly at leaky spots4 ,when several engines are installed near one another1 each should be provided with a special exhaust-pipe2 otherwise it may happen1 when the engines are all running at once1 that the products of combustion discharged by the one may cause a back pressure detrimental to the exhaust of the next4 ,it is possible to employ a pipe common to all the exhausts if the pipe starts from a point beyond the exhaust-chests1 in which case ,y-joints and not ,t-joints are to be used4 ,the manner of securing the pipes to walls by means of detachable hangers1 lined with asbestos1 is shown in a general way in the accompanying ,fig4 #ec4 ,the object of this arrangement is to render detachment easy and to prevent the transmission of shocks to the masonry4 ,the precautions to be taken for muffling the noise of the exhaust will be discussed later4 ,the end of the exhaust-pipe should be slightly curved down in order to prevent the entrance of rain4 ,exhaust-pipes are subjected to considerable vibration1 due to the sudden discharge of the gases4 ,to protect the joints1 the pipes should be rigidly fastened in place4 ,illustration3 ,,fig4 #ec4--,method of securing pipes to walls4 ,legal ,authorization4--,in most countries gas-engines may be installed only in accordance with the provision of general or local laws1 which impose certain conditions4 ,these laws vary with different localities1 for which reason they are not discussed here4 ,,chapter ,,iv ,,foundation ,,and ,,exhaust ,the reader will remember from what has already been said that a gas-engine is a motor which1 more than any other1 is subjected to forces1 suddenly and repeatedly exerted1 producing violent reactions on the foundation4 ,it follows that the foundation must be made particularly resistant by properly determining its shape and size and by carefully selecting the material of which it is to be built4 ,the ,foundation ,materials4--,well-hardened brick should be used4 ,the top course of bricks should be laid on edge4 ,it is advisable to increase the stability of the foundation by longitudinally elongating it toward the base1 as shown in the accompanying diagram 7,fig4 #ed74 ,as a binding material1 only mortar composed of coarse sand or river sand and of good cement1 should be used4 ,instead of coarse sand1 crushed slag1 well-screened1 may be employed4 ,the mortar should consist of #b_/c slag and #a_/c cement4 ,oil should not in any way come into contact with the mortar2 it may percolate through the cement and alter its resistant qualities4 ,as in the construction of all foundations1 care should be taken to excavate down to good soil and to line the bottom with concrete1 in order to form a single mass of artificial stone4 ,a day or two should be allowed for the masonry to dry out1 before filling in around it4 ,when the engine is installed on the ground floor above a vaulted cellar1 the foundation should not rest directly on the vault below or on the joists1 but should be built upon the very floor of the cellar1 so that it passes through the planking of the ground floor without contact4 ,illustration3 ,,fig4 #ed4--,method of building the foundation4 ,when the engine is to be installed on a staging1 the method of securing it in place illustrated in ,fig4 #ee should be adopted4 ,although a foundation1 built in the manner described1 will fulfill the usual conditions of an industrial installation1 it will be inadequate for special cases in which trepidation is to be expected4 ,such is the case when engines are to be installed in places where1 owing to the absence of factories1 it is necessary to avoid all nuisance1 such as noise1 trepidations1 odors1 and the like4 ,illustration3 ,,fig4 #ee4--;,elevated foundation4 ,vibration4--,in order to prevent the transmission of vibration1 the foundation should be carefully insulated from all neighboring walls4 ,for this purpose various insulating substances called anti-vibratory are to be recommended4 ,among these may be mentioned horsehair1 felt packing1 cork1 and the like4 ,the efficacy of these substances depends much on the manner in which they are applied4 ,it is always advisable to interpose a layer of one of these substances1 from one to four inches thick1 between the foundation and the surrounding soil1 the thickness varying with the nature of the material used and the effect to be obtained4 ,between the bed of concrete1 mentioned previously1 and the foundation-masonry and between the foundation and the engine-frame1 a layer of insulating material may well be placed4 ,preference is to be given to substances not likely to rot or at least not likely to lose their insulating property1 when acted upon by heat1 moisture or pressure4 ,here it may not be amiss to warn against the utilization of cork for the bottom of the foundation2 for water may cause the cork to swell and to dislocate the foundation or destroy its level4 ,the employment of the various substances mentioned does not entail any great expense when the foundations are not large and the engines are light4 ,but the cost becomes considerable when insulating material is to be employed for the foundation of a #cj to #ej horse-power engine and upwards4 ,for an engine of such size the author recommends an arrangement as simple as it is efficient1 which consists in placing the foundation of the engine in a veritable masonry basin1 the bottom of which is a bed of concrete of suitable thickness4 ,the foundation is so placed that the lateral surfaces are absolutely independent of the supporting-walls of the basin thus formed4 ,care should be taken to cover the bottom with a layer of dry sand1 rammed down well1 varying in thickness with each case4 ,this layer of sand constitutes the anti-vibratory material and confines the trepidations of the engine to the foundation4 ,as a result of this arrangement1 it should be observed that1 being unsupported laterally1 the foundation should be all the more resistant1 for which reason the base-area and weight should be increased by #cj to #dj per cent4 ,the expense entailed will be largely offset by saving the cost of special anti-vibratory substances4 ,in places liable to be flooded by water1 the basin should be cemented or asphalted4 ,when the engine is of some size and is intended for the driving of one or more dynamos which may themselves give rise to vibrations1 the dynamos are secured directly to the foundation of the engine1 which is extended for that purpose1 so that both machines are carried solidly on a single base4 ,the foregoing outline should not lead the proprietor of a plant to dispense with the services of experts1 whose long experience has brought home to them the difficulties to be overcome in special cases4 ,it should here be stated1 as a general rule1 that the bricks should be thoroughly moistened before they are laid in order that they may grip the mortar4 ,after having been placed on the foundation and roughly trimmed with respect to the transmission devices1 the engine is carefully leveled by means of hardwood wedges driven under the base4 ,this done1 the bolts are sealed by very gradually pouring a cement wash into the holes1 and allowing it to set4 ,when the holes are completely filled and the bolts securely fastened in place1 a shallow rim1 or edge of clay1 or sand is run around the cast base1 so as to form a small box or trough1 in which cement is also poured for the purpose of firmly binding the engine frame and foundation together4 ,when1 as in the case of electric-light engines1 single extra-heavy fly-wheels are employed1 provided with bearings held in independent cast supports1 the following rule should be observed to prevent the overheating due to unlevelness1 which usually occurs at the bushings of these bearings3 ,that part of the foundation which is to receive such a support should rest directly on the concrete bed and should be rigidly connected at the bottom with the main foundation4 ,when the foundation is completely blocked up1 the fly-wheel bearing with its support is hung to the crank-shaft2 and not until this is effected is the masonry at the base of the support completed and rigidly fixed in its proper position4 ,for very large engines1 the foundation-bolts should be particularly well sealed into the foundation4 ,in order to attain this end the bricks are laid around the bolt-holes1 alternately projected and retracted as shown in ,fig4 #ed4 ,broken stone is then rammed down around the fixed bolt2 in the interstices cement wash is poured4 ,air ,vibration1 etc4--,vibration due chiefly to the transmission of noises and the displacement of air by the piston should not be confused with the trepidations previously mentioned4 ,the noise of an engine is caused by two distinct phenomena4 ,the one is due to the transmitting properties of the entire solid mass constituting the frame1 the foundation1 and the soil4 ,the other is due to vibrations transmitted to the air4 ,in both cases1 in order to reduce the noise to a minimum1 the moving parts should be kept nicely adjusted1 and above all1 shocks avoided1 the more harmful of which are caused by the play between the joint at the foot of the connecting-rod and the piston-pin1 and between the head of the connecting-rod and the crank-shaft4 ,although smooth running of the engine may be assured1 there is always an inherent drawback in the rapid reciprocating movement of the piston4 ,in large1 single-acting gas-engines1 a considerable displacement of air is thus produced4 ,in the case of a forty horse-power engine having a cylinder diameter and piston-stroke respectively of #ac-c_/d inches and #ba-c_/e inches1 it is evident that at each stroke the piston will displace about #b cubic feet of air1 the effect of which will be doubled when it is considered that on the forward stroke back pressure is created and on the return stroke suction is produced4 ,the air motion caused by the engine is the more readily felt as the engine-room is smaller4 ,if the room1 for example1 be #i feet by #ae feet by #h feet1 the volume will be #a1jhj cubic feet4 ,from this it follows that the #b cubic feet of air in the case supposed will be alternately displaced six times each second1 which means the displacement of #ab cubic feet at short intervals with an average speed of #eej feet per minute4 ,such vibrations transmitted to halls or neighboring rooms are due entirely to the displacement of the air4 ,in installations where the air-intake of the engine is located in the engine-room1 a certain compensation is secured1 at the period of suction1 between the quantity of air expelled on the forward stroke of the piston and the quantity of air drawn into the cylinder4 ,from this it follows that the vibration caused by the movement of the air is felt less and occurs but once for two revolutions of the engine4 ,this phenomenon is very manifest in narrow rooms in which the engine happens to be installed near glass windows4 ,by reason of the elasticity of the glass1 the windows acquire a vibratory movement corresponding in period with half the number of revolutions of the engine4 ,it follows from the preceding that1 in order to do away with the air vibration occasioned by the piston in drawing in and forcing out air in an enclosed space1 openings should be provided for the entrance of large quantities of air1 or a sufficient supply of air should be forced in by means of a fan4 ,the author ends this section with the advice that all pipes in general and the exhaust-pipe in particular be insulated from the foundation and from the walls through which they pass as well as from the ground1 as metal pipes are good conductors of sound and liable to carry to some distance from the engine the sounds of the moving parts4 ,exhaust ,noises4--,among the most difficult noises to muffle is that of the exhaust4 ,indeed1 it is the exhaust above all that betrays the gas-engine by its discharge to the exterior through the exhaust-pipe4 ,the most commonly employed means for rendering the exhaust less perceptible consists in extending the pipe upward as far as possible1 even to the height of the roof4 ,this is an easy way out of the difficulty2 but it has a bad effect on the operation of the engine4 ,it reduces the power generated and increases the consumption1 as will be explained in a special paragraph4 ,expansion-boxes1 more commonly called exhaust-mufflers1 considerably deaden the noise of explosion by the use of two or three successive receptacles4 ,but this remedy is attended with the same faults that mark the use of extremely long pipes4 ,the best plan is to mount a single exhaust-muffler near the discharge of the engine in the engine-room itself1 where it will serve at least the purpose of localizing the sound4 ,illustration3 ,,fig4 #ef4--;,exhaust-muffler4 ,the employment of pipes of sufficiently large cross-section to constitute expansion-boxes in themselves will also muffle the exhaust4 ,a more complete solution of the problem is obtained by causing the exhaust-pipe1 after leaving the muffler1 to discharge into a masonry trough having a volume equal to twelve times that of the engine-cylinder 7,fig4 #ef74 ,this trough should be divided into two parts1 separated by a horizontal iron grating4 ,into the lower part1 which is empty1 the exhaust-pipe discharges2 in the upper part1 paving-blocks or hard stones not likely to crumble with the heat1 are placed4 ,between this layer of stones and the cover it is advisable to leave a space equal to the first4 ,here the gases may expand after having been divided into many parts in passing through the spaces left between adjacent stones4 ,the trough should not be closed by a rigid cover2 for1 although efficient muffling may be attained1 certain disadvantages are nevertheless encountered4 ,it may happen that in a badly regulated engine1 unburnt gases may be discharged into this trough1 forming an explosive mixture which will be ignited by the next explosion1 causing considerable damage4 ,still1 the explosion will be less dangerous than noisy4 ,it may be mentioned in passing that this disadvantage occurs rarely4 ,a second arrangement consists in superposing the end of the exhaust-pipe upon a casing of suitable size1 which casing is partitioned off by several perforated baffle-plates4 ,this casing is preferably made of wood1 lined with metal1 so that it will not be resonant4 ,the size of the casing1 the number of partitions and their perforations1 and the manner of disposing the partitions have much to do with the result to be obtained4 ,here again the experience of the expert is of use4 ,various other systems are employed1 depending upon the particular circumstances of each case4 ,among these systems may be mentioned those in which the pipe is forked at its end to form either a yoke 7,fig4 #eg7 or a double curve1 each branch of which terminates in a muffler 7,fig4 #eh74 ,illustration3 ,,fig4 #eg4 ,illustration3 ,,fig4 #eh4--,two types of exhaust-mufflers4 ,it should be observed that1 under ordinary conditions1 noises heard as hissing sounds are often due to the presence of projections1 or to distortion of the pipes near the discharge opening4 ,consequently1 in connecting the pipes1 care should be taken that the joints or seams have no interior projections4 ,occasionally1 water may be injected into the exhaust-muffler in order to condense the vapors of the exhaust1 the result being a deadening of the noises2 but in order to be truly efficient this method should be employed with discretion1 for which reason the advice of an expert is of value4 ,,chapter ,v ,,water ,,circulation ,circulation of water in explosion-engines is one of the essentials of their perfect operation4 ,two special cases are encountered4 ,in the one the jacket of the engine is supplied with running water2 in the other1 reservoirs are employed1 the circulation being effected simply by the difference in specific gravity in a thermo-siphon apparatus4 ,coolers are also used4 ,running ,water4--,a water-jacket fed from a constant source of running water1 such as the water mains of a town1 is certainly productive of the best results1 the supply1 moreover1 being easily regulated2 but the system is not widely used because the water runs away and is entirely lost4 ,if running water be employed1 the outlet of the jacket is so disposed that the water gushes out immediately on leaving the cylinder1 and that the flow is visible and accessible1 in order that the temperature may be tested by the hand4 ,apart from the relatively great cost of water in towns1 the use of running water is objectionable on account of its chemical composition4 ,though it may be clear and limpid1 it frequently contains lime salts1 carbonates1 sulphates1 and silicates which are precipitated by reason of the sudden change of temperature to which the water is subjected as it comes into contact with the walls of the cylinder4 ,that part of the water-jacket surrounding the head or explosion-chamber1 where the temperature is necessarily the highest1 becomes literally covered with calcareous incrustations1 which are the more harmful because they are bad conductors of heat and because they reduce and even obstruct the passage exactly at the point where the water must circulate most freely to do any good4 ,if the circulating water be pumped into the jacket1 it is preferable1 wherever possible1 to use cistern water1 which is not likely to contain lime salts in suspension4 ,if river water be used1 it should be free from the objections already mentioned1 which are all the more grave if the water be muddy1 as sometimes happens4 ,the water-jacket can be easily freed from all non-adhering deposits by flushing it periodically through the medium of a conveniently placed cock4 ,it is always preferable to pass the water through a reservoir where its impurities can settle1 before it flows to the cylinder4 ,in the case considered1 the water usually has an average temperature of #ed to #fj degrees ,f41 under which condition the hourly flow should be at least #e-a_/b gallons per horse-power per hour1 the temperature rising at the outlet-pipe of the cylinder to #adj and #aeh degrees ,f41 which should not be surpassed4 ,however1 in engines working with high compression1 #ajd to #abb degrees ,f4 should not be exceeded4 ,if the water-jacket be fed by a reservoir1 it is essential that the reservoir comply with the following conditions3 ,in horizontal engines the water-inlet is always located in the base of the cylinder1 while the outlet is located at the top4 ,by providing the inlet-pipe extending to the cylinder with a cock1 the circulation of water can be regulated to correspond with the work performed by the engine4 ,another cock at the end of the outlet-pipe near the reservoir serves1 in conjunction with the first1 to arrest the circulating water4 ,when the weather is very cold or when the cylinder must be repaired1 these two cocks may be closed1 and the pipe and water-jacket of the cylinder drained by means of the drain-cock ,v 7,fig4 #ei71 mounted at the inlet of the engine's water-jacket4 ,in order that the pressure of the atmosphere may not prevent the flowing of the water1 the highest part of the pipe is provided with a small tube1 ,t1 communicating with the atmosphere4 ,illustration3 ,,fig4 #ei4--,thermo-siphon cooling system4 ,on account of the importance of preventing losses of the charge in the pipes the author recommends the utilization of sluice-valves of the type shown in ,fig4 #fj1 instead of the usual cone or plug type4 ,illustration3 ,,fig4 #fj4--,vanne sluice-cock4 ,water-,tanks4--,the reservoir is mounted in such a way that its base is flush with the top of the cylinder2 it should be as near as possible to the cylinder in order to obviate the use of long inlet and return pipes4 ,this fact1 however1 does not necessarily render it advisable to place the reservoir in the engine-room2 for such a disposition is doubly disadvantageous in so far as it does not permit a sufficiently rapid cooling of the circulating water by reason of the high temperature of the surrounding air1 and in so far as it is liable to cause the formation of vapors which injuriously affect the engine4 ,consequently1 the reservoir should be placed in as cool a place as possible1 preferably even in the open air2 for the water is not likely to freeze1 except when it has been allowed to stand for a considerable time4 ,the reservoir should be left uncovered so as to facilitate cooling by the liberation of the vapors formed on the surface of the water4 ,circulation being effected solely by the difference in specific gravity or density between the warmer water emerging from the cylinder and the cooler water which flows in from the reservoir1 the slightest obstruction will impede the flow4 ,hence1 the cross-section of the pipes should not be less than that of the inlet and outlet openings of the cylinder of the engine4 ,good circulation cannot be attained if the water must overcome inclines or obstacles in the pipes themselves4 ,instead of elbows1 long curves of great radius1 limited to the smallest possible number1 should be employed4 ,this is particularly true of the return-pipe extending from the cylinder back to the reservoir4 ,for this pipe a minimum incline of #aj to #ae per cent4 should be allowed1 in order that the water may run up into the reservoir4 ,the height of the water in the reservoir should be from #b to #d inches above the discharge of the return-pipe4 ,in order to maintain this level it is advisable to use some automatic device such as a float-valve1 in which case the reservoir should not be allowed to become too full4 ,illustration3 ,,fig4 #fa4--;,correct arrangement of tanks and piping4 ,the size of a reservoir is determined by the engine2 it should be large enough to enable the engine to run smoothly at its maximum load for several hours consecutively4 ,under these conditions1 the reservoir should have a capacity of #de to #ee gallons per horse-power for engines with hit-and-miss admission1 and #ee to #fe gallons for engines controlled by variable admission4 ,it is not advisable to employ reservoirs having a capacity of more than #ccj to #ddj gallons1 the usual diameter being about #c feet4 ,illustration3 ,,fig4 #fb4--;,incorrect arrangement of tanks and piping4 ,if the power of the engine be such that several reservoirs are necessary1 then the reservoirs should be connected in such a manner that the top of the first communicates with the bottom of the next and so on1 the first reservoir receiving the water as it comes from the cylinder 7,fig4 #fa74 ,intercommunication of the reservoirs by means of a common top tube 7a7 is objectionable2 and simultaneous intercommunication at top and bottom 7a and b7 is ineffective1 so far as one of the reservoirs is concerned 7,fig4 #fb74 ,illustration3 ,,fig4 #fc4--,tanks connected by inclined pipes4 ,the reservoirs are true thermo-siphons4 ,consequently the water should be methodically circulated2 in other words1 the hottest water1 flowing from the engine into the top of the first reservoir and having1 for example1 a temperature of #ajd degrees ,f41 is cooled off to #hf degrees ,f4 and drops to the bottom of the reservoir1 thence to be driven1 at a temperature sensibly equal to #hf degrees ,f41 to the second reservoir1 where a further cooling of #ah degrees ,f4 takes place4 ,in passing on to the following reservoirs the temperature is still further lowered1 until the water finally reaches its minimum temperature1 after which it flows back to the engine-cylinder4 ,illustration3 ,,fig4 #fd4--;,circulating pump with by-pass4 ,in order to effect this cooling1 the reservoirs can be connected in several ways4 ,the most common method1 as shown in ,fig4 #fc1 consists in connecting the reservoirs by oblique pipes4 ,this is open to criticism1 however1 since leakage occurs1 caused by the employment of elbows which retard the circulation4 ,a less cumbrous and more efficient method of connection consists in joining the reservoirs by a single pipe at the top1 as shown in ,fig4 #fa2 but care must be taken to extend this pipe at the point of its entrance into the adjoining reservoir by means of a downwardly projecting extension1 or to fit its discharge-end with a box1 closed by a single partition1 open at the bottom4 ,in order to prevent incrustation of the water-jacket surrounding the cylinder1 a pound of soda per #ag cubic feet of the reservoir capacity is monthly introduced1 and the jacket flushed weekly by a cock conveniently mounted near the cylinder 7,fig4 #ei74 ,the jacket is thus purged of calcareous sediments1 which are prevented by the soda from adhering to the metal4 ,the flushing-cock mentioned also serves to drain the water-jacket of the cylinder in case of intense or persistent cold1 which would certainly freeze the water in the jacket1 thereby cracking the cylinder or the exposed pipes4 ,in order to regulate the circulation of the water in accordance with the work performed by the engine1 a cock should be fitted to the water supply pipe at a convenient place4 ,in engines of large size1 driven at full load for long periods1 cooling by natural circulation is often inadequate4 ,in such cases1 circulation is quickened by a small rotary or reciprocating pump1 driven from the engine itself and fitted with a by-pass provided with a cock4 ,this arrangement permits the renewal of the natural thermo-siphon circulation in case of accident to the pump 7,fig4 #fd74 ,illustration3 ,,fig4 #fe4--,water-cooler in which tree branches are employed4 ,coolers4--,the arrangement which is illustrated in ,fig4 #fe1 and which has the merit of simplicity1 will be found of service in cooling the water4 ,it comprises a tank ,b surmounted by a set of trays ,e1 formed of frames to which iron rods are secured1 spaced #a to #b feet apart1 so as to form superimposed series separated by #a-a_/b to #b-a_/c feet4 ,on these trays bundles of tree branches are placed4 ,the cold water at the bottom of the tank is forced by the pump ,pi into the water-jacket1 from which it emerges hot1 and flows through the pipe ,t1 which ends in a sprinkler ,g1 formed of communicating tubes and perforated with a sufficient number of holes to enable the water to fall upon the trays in many drops4 ,thus finely divided1 the water falls from one tray to another1 retarded as it descends by the bundles of tree branches4 ,it finally reaches the tank in a very cold condition and is then ready to be pumped to the engine4 ,birch branches are to be preferred on account of their tenuity4 ,great care should be taken to cover the tank with a sheet-metal closure in order to prevent twigs and foreign bodies from entering and from being drawn into the pump4 ,illustration3 ,,fig4 #ff4--;,fan-cooler4 ,in the following table the dimensions of an operative apparatus of this kind are given1--an apparatus1 moreover1 that may be constructed of wood or of iron3-- ,table ,headings-- ,column ,a3 ,horse-power4 ,column ,b3 ,volume in cubic ft4 ,column ,c3 ,base4 ,column ,d3 ,height4 ,column ,e3 ,height of tray-base4 ,column ,f3 ,pump--,capacity in gals4 per min4 ,tank4 ,a4 ,b4 ,c4 ,d4 ,e4 ,f4 #cj #aje #d4i' x #d4i' #d4d' #f4f' #af4ga #dj #aed #e4b' x #e4b' #e4f' #g4d' #ah4fi #ej #aij #e4g' x #e4g' #f4d' #h4a' #ba4ii #ge #cej #f4f' x #f4f' #h4a' #i4a' #ce4ah #ajj #dij #g4d' x #g4d' #i4a' #i4a' #dc4ih ,in order that the water may not drop to one side1 the base of the apparatus should be made #aj to #ab inches less in width than the tank4 ,the size of these apparatus may be considerably reduced by constructing them in the form of closed chests1 into the bottom of which air maybe injected by means of fans in order to accelerate cooling 7,fig4 #ff74 ,,chapter ,,vi ,,lubrication ,lubrication is a subject that should be studied by every gas-engine user4 ,so far as the piston is concerned it is a matter of the utmost importance4 ,the piston does its work under very peculiar conditions4 ,it is driven at great linear velocities2 and it is1 moreover1 subjected to high temperatures which have nothing in common with good lubrication if care be not exercised4 ,the piston is the essential1 vital element of an engine4 ,upon its freedom from leakage depends the maintenance of a proper compression1 and1 consequently1 the production of power and economical consumption4 ,as it travels forward and as it recedes from the explosion-chamber1 it uncovers more and more of the frictional surface constituting the interior wall of the cylinder4 ,this surface1 as a result1 is regularly brought into contact with the ignited1 expanding gases after each explosion4 ,for this reason the oil which covers the wall is constantly subjected to high temperatures1 by which it is likely to be volatilized and burned4 ,therefore1 the first condition to be fulfilled in properly lubricating the piston is a constant and regular supply of oil4 ,quality of ,oils4--,for cylinder lubrication only the very best oils should be used2 perfect lubrication is of such importance that cost should not be considered4 ,besides1 the surplus oil which is usually caught in the drip-pan is by no means lost4 ,after having been filtered it can be used for lubricating the bearings of the crank1 the cam-shaft1 and like parts4 ,cylinder-oil should be exceedingly pure1 free from acids1 and composed of hydrocarbons that leave no residue after combustion4 ,only mineral oils1 therefore1 are suitable for the purpose4 ,those oils should be selected which1 with a maximum of viscosity1 are capable of withstanding great heat without volatilizing or burning4 ,the point at which a good cylinder-oil ignites should not be lower than #ece degrees ,f4 ,whether an oil possesses this essential quality is easily enough ascertained in practice without resorting to laboratory tests4 ,all that is necessary is to heat the oil in a metal vessel or a porcelain dish4 ,in order that the temperature may be uniform the vessel is shielded from the direct flame by interposing a piece of sheet metal or a layer of dry sand4 ,as soon as gases begin to arise a lighted match is held over the oil4 ,when the gases are ignited the thermometer reading is taken1 the instrument being immersed in the oil4 ,the temperature recorded is that corresponding with the point of ignition4 ,for cylinder lubrication ,american mineral oil is preferable to ,russian oil4 ,the specific gravity should lie somewhere between 4#hhf and 4#hhi at #gj degrees ,f4 ,oil of this quality begins to evaporate at about #cfe degrees ,f4 ,ignition occurs at #ece degrees ,f4 ,the point of complete combustibility lies between #fbe and #fde degrees ,f4 ,oil of this quality solidifies at #ci or #da degrees ,f4 ,its color is a reddish yellow with a greenish fluorescence4 ,compared with water its degree of viscosity lies between #aa4e and #ab4e at a temperature of #adj degrees ,f4 ,before lubricating other parts of the engine with oil that has been used for the piston1 heavy particles and foreign matter1 such as dust1 bearing incrustations1 and the like1 should be filtered out4 ,the piston-pivot and the connecting-rod head are preferably lubricated with fresh oil1 because their constant movement renders inspection difficult and the control of lubrication irksome4 ,a good1 industrial mineral oil of usual market quality will be found satisfactory4 ,in order to bring home the importance of employing good cylinder-oil and of proper lubrication the author can only state that in his personal experience he has frequently detected losses varying from #aj to #ae per cent4 in the power developed by engines poorly lubricated4 ,types of ,lubricators4--,among the more common apparatus employed for automatically lubricating the cylinder1 the author mentions an ,english oiler of the type pictured in ,fig4 #fg which is driven simply by a belt from the intermediary shaft1 and which rotates the pulley ,p secured on the shaft a of the apparatus1 at a very slow speed4 ,the shaft a is provided at its end with a small crank1 from which a small iron arm f is suspended1 which arm dips in the oil contained in the cup ,g of the oiler4 ,when the shaft a is turned this arm1 as it sweeps through the oil-bath1 collects a certain quantity of oil which it deposits on the collector b4 ,from this spindle the oil passes through an outlet-pipe opening into the bottom of the oiler1 and thence to the cylinder4 ,the entire apparatus is closed by a cover ,d which can be easily removed in order to ascertain the quantity of oil still remaining in the apparatus4 ,many other systems are utilized which1 like the one that has been described1 enable the feed to be controlled4 ,often small force-pumps are employed as cylinder-lubricators4 ,whatever may be the type selected1 preference should be given to that in which the feed is visible 7,fig4 #fh74 ,illustration3 ,,fig4 #fg4--;,an automatic ,english oiler4 ,if the oil be fed under pressure the cylinder is more constantly lubricated4 ,pressure-lubricators are nowadays widely used on large engines4 ,it is advisable to add a little salt to the water contained in sight-feed lubricators so that the drop of oil is easily freed4 ,these oil-pumps are provided with small check-valves at their outlets as well as at the inlets of cylinders4 ,in order that pressure-lubricators may operate perfectly they should be regularly inspected and the check-valves ground from time to time4 ,the lubrication of the crank-shaft and of the two connecting-rod heads should receive every attention4 ,illustration3 ,,fig4 #fh4--,sight-feed lubricating-pump4 ,illustration3 ,,fig4 #fi4--,method of oiling the piston and end of the connecting-rod4 ,lubricating devices should be employed which1 besides being efficient1 do not necessitate the stopping of the engine in order to oil the bearings4 ,the foot of the connecting-rod at the point where it is pivoted to the piston is generally lubricated with cylinder-oil which is supplied by a tube mounted in the proper place across the piston-wall 7,fig4 #fi74 ,this arrangement may be adequate enough for small engines2 but it is not sufficiently sure for engines of considerable size4 ,an independent lubricating system should be employed1 lubrication being effected either by a splasher mounted in front of the cylinder or by a lubricator secured to the connecting-rod by which the pivot is lubricated through the medium of a small tube supplying special oil 7,fig4 #ba74 ,the head of the connecting-rod where it meets the crank1 must also be carefully lubricated because of the important nature of the work which it must perform1 and because of the shocks to which it is subjected at each explosion4 ,for motors of high power the system which seems to give most satisfactory results is that illustrated in ,fig4 #gj4 ,the arrangement there shown consists of an annular vessel secured at one side of the crank and turning concentrically on its axis2 the vessel being connected with a long tube extending into a channel formed in the crank and discharging at the surface of the crank-pin within the bearing at the head of the connecting-rod4 ,an adjustable sight-feed lubricator conducts the oil along a pipe to the vessel4 ,turning with the shaft1 the vessel retains the oil in the periphery so that the feed in the previously mentioned channel in the connecting-rod head1 is constant4 ,illustration3 ,,fig4 #gj4--,method of oiling the crank-shaft4 ,the main crank-shaft bearings are more easily lubricated4 ,among the systems commonly used with good results may be mentioned that shown in ,fig4 #ga1 in which the half section represents a small tube starting from the bearing and terminating in the interior of an oil recess or reservoir cast integrally with the bearing-cap4 ,this reservoir is filled up to the level of the tube opening4 ,a piece of cotton waste held on a small iron wire is inserted in the tube1 part of the cotton being allowed to hang down in the reservoir4 ,this cotton serves as a kind of siphon and feeds the bearing by capillary attraction with a constant quantity of oil1 the supply being regulated by varying the thickness of the cotton4 ,when the motor is stopped1 the cotton should be removed in order that oil-feeding may not uselessly continue4 ,glass1 sight-feed lubricators with stop-cocks1 are very often used on crank-shafts4 ,they are cleaner and much more easily regulated4 ,of all shaft-bearing lubricators1 those which are most to be recommended are of the revolving-ring type 7,fig4 #gb74 ,they presuppose1 however1 bearings of large size and a special arrangement of bushings which renders their application somewhat expensive4 ,furthermore1 the revolving-ring system can hardly be used in connection with engines of less than #bj horse-power4 ,since the system is applied almost exclusively to dynamo-shafts1 it need not here be described in detail4 ,as its name indicates1 it consists of a metal ring having a diameter larger than that part of the shaft from which it is suspended and by which it is rotated4 ,the lower part of the ring is immersed in an oil bath so that a certain quantity of lubricant is continually transferred to the shaft4 ,illustration3 ,,fig4 #ga4--;,cotton-waste lubricator4 ,the revolving ring bearing should be fitted with a drain-cock and a glass tube in order to control the level of the oil in the bearing4 ,many manufacturers have adopted lubricating devices for valve-stems1 and especially for exhaust-valves4 ,the system adopted consists of a small tube curved in any convenient direction and discharging in the stem-guide4 ,the free end is provided with a plug4 ,a few drops of petroleum are introduced once or twice a day4 ,illustration3 ,,fig4 #gb4--,ring type of bearing oiler4 ,the lubrication of an engine entails certain difficulties which are easily overcome4 ,one of these is the splashing of oil by the connecting-rod head4 ,in order that this splashed oil may be collected in the base of the engine a suitably curved sheet-metal guard is mounted over the crank4 ,a more serious difficulty is presented when the oil from a crank-bearing finds its way to the hub of the fly-wheel1 whence it is driven by the centrifugal force to the rim4 ,the oil is not only splashed against the walls of the engine-room1 but it also destroys the adhesion of the belt if the fly-wheel be employed as a pulley4 ,in order to overcome this objection the oil is prevented from spreading along the shaft by means of a circular guard 7,fig4 #gc7 mounted on that portion of the shaft toward the interior of the bearing4 ,illustration3 ,,fig4 #gc4--,shaft with oil-guard4 ,the problem of lubrication is of particular importance if the engine is driven for several days at a time without a stop4 ,this happens in the case of mill and shop engines4 ,lubricators of large volume or lubricators which can be readily filled without stopping the engine should be employed4 ,,chapter ,,vii ,,the ,,conditions ,,of ,,perfect ,,operation ,general ,care4--,gas-engines1 as well as most machines in general1 should be kept in perfect condition4 ,cleanliness1 even in the case of parts of secondary importance1 is indispensable4 ,unpainted and polished surfaces such as the shaft of the engine1 the distributing cam-shafts1 the levers1 the connecting-rod and the like1 should be kept in a condition equal to that when they were new4 ,the absence of all traces of rust or corrosion in these parts affords sufficient evidence of the care taken of the invisible members such as the piston1 the valves1 ignition devices1 and the like4 ,lubrication4--,the rubbing surfaces of a gas-engine should be regularly and perfectly lubricated4 ,the absence of lost motion and backlash in the bearings1 guides1 and joints is of particular importance not only because of its influence on steady and silent running1 but also on the power developed and on the consumption4 ,as we have already seen in the chapter on lubrication1 a special quality of oil should be employed for the lubrication of the cylinder4 ,the feed of the lubricator supplying this most vital part of the engine is so regulated that it meets the actual requirements with the utmost nicety possible4 ,in a subsequent chapter1 in which faulty operation will be discussed1 it will be shown how too much and too little oil may cause serious trouble4 ,tightness of the ,cylinder4--,the amount of power developed depends principally on the degree of compression to which the explosive mixture is subjected4 ,the economical operation of the engine depends in general upon perfect compression4 ,it is1 therefore1 necessary to keep those parts in good order upon which the tightness of the cylinder depends4 ,these parts are the piston1 the valves1 and their joints1 and the ignition devices whether they be of the hot-tube or electrical variety4 ,in order to prevent leakage at the piston1 the rings should be protected from all wear4 ,it is of the utmost importance that the surfaces both of the piston and of the cylinder1 be highly polished so that binding cannot occur4 ,in cleansing the cylinder1 emery paper or abrasive powder should not be employed2 for the slightest particle of abrasive between the surfaces in contact will surely cause leakage4 ,the oil and dirt1 which is turned black by friction and which may adhere to the piston rings1 should be washed away with petroleum4 ,similarly the other parts of the cylinder should be cleaned to which burnt oil tends to adhere4 ,valve-,regrinding4--,the valves should be regularly ground4 ,even in special cases where they may show no trace of rapid wear they should be removed at least every month4 ,in order to avoid any accident1 care should be taken in adjusting the valves after the cap has been unbolted not to introduce a candle or a lighted match either in the valve-chambers or in the cylinder1 without first closing the gas-cock4 ,furthermore1 a few turns should be given to the engine1 in order to drive out any explosive mixture that may still remain in the cylinder or the connected passages4 ,the exhaust-valve1 by reason of the high temperature to which the disk and the seat are subjected1 should receive special attention4 ,the valve should be ground on its seat every two or three months at least1 depending upon the load of the engine4 ,bearings and ,crosshead4--,the bushings of the engine shaft should always be held tightly in place4 ,the looseness to which they are liable1 particularly in gas-engines on account of the sharp explosions1 tends to unscrew the nuts and to hasten the wear of the brass1 which is the result of frequent tightening4 ,the slightest play in the bearings of the engine-shaft as well as in the bearings of connecting-rods increases the sound that engines naturally produce4 ,governor4--,the governor should receive careful attention so far as its cleanliness is concerned2 for if its operation is not easy it is apt to become lazy and to lose its sensitiveness4 ,if the governor be of the ball type1 or of the conical pendulum type operated by centrifugal force1 it is well to lubricate each joint without excess of oil4 ,in order to prevent the accumulation and the solidification of oil1 the governor should be lubricated from time to time with petroleum4 ,if the governor is actuated by inertia1 which is the case in most engines of the hit-and-miss variety1 it needs less care2 still1 it is advisable to keep the contact at which the thrust takes place well oiled4 ,the operation of any of these governors is usually controlled by the tension of a spring1 or by a counterweight4 ,in order to increase the speed of the engine1 or in other words1 to increase the number of admissions of gas in a given time1 all that is usually necessary is to tighten up the spring1 or to change the position of the counterweight4 ,it should be possible to effect this adjustment while the engine is running in such a manner that the speed can be easily changed4 ,joints4--,in most well-built engines the caps of the valve-chests and other removable parts are secured metal on metal without interposing special joints4 ,in other words1 the surfaces are themselves sufficiently cohesive to insure perfect tightness4 ,in engines which are not of this class1 asbestos joints are very frequently employed1 particularly at the exhaust-valve cap and the suction-valve4 ,in some engines1 where for any reason it is necessary frequently to detach the caps1 certain precautions should be taken to protect the joints so that they may not be exposed to deterioration whenever they are removed4 ,for this purpose1 they are first immersed in water in order to be softened1 then dried and washed with olive or linseed oil on the side upon which they rest in the engine4 ,on the cap side they are dusted with talcum or with graphite4 ,treated in this manner1 the joint will adhere on one side and will be easily released on the other4 ,joints that are liable to come in contact with the gases in the explosion-chamber should be free from all projections toward the interior of the cylinder2 for during compression these uncooled projections may become incandescent and may thus cause premature ignition4 ,as a general rule when the cap is placed in position the joint should be retightened after a certain time1 when the surfaces have become sufficiently heated4 ,in order to tighten the joints the bolts and nuts should not be oiled2 otherwise the removal of the cap becomes difficult4 ,water ,circulation4--,in a previous chapter1 the importance of the water circulation and the necessity of keeping the cylinder-jacket hot1 have been sufficiently dwelt upon4 ,as the cylinder tends to become hotter with an increase in the load1 because of the greater frequency of explosions1 it is advisable to regulate the flow of the water in order to prevent its becoming more than sufficient in quantity when the engine is lightly loaded2 for under these conditions the cylinder will be cold and the explosive mixture will be badly utilized4 ,a suitable temperature of #adj to #aeh degrees ,f4 is easily maintained by adjusting the circulation of the water4 ,this can be accomplished by providing the water-inlet pipe leading to the cylinder with a cock which can be opened more or less1 as may be necessary4 ,the temperature of #adj to #aeh degrees ,f41 which has been mentioned1 may1 at first blush1 seem rather high because it would be impossible to keep the hand on the outlet-pipe4 ,the cylinder1 however1 will not become overheated so long as it is possible to hold the hand beneath the jacket near the water-inlet4 ,this relates only to engines having a compression of #ej to #ajj lbs4 per square inch4 ,for engines of higher compression1 a lower running temperature will be safer4 ,on this matter the instructions of the engine maker should be carried out4 ,adjustment4--,gas-engines1 at least those which are built by trustworthy firms1 are always put to the brake test before they are sent from the shops1 and are adjusted to meet the requirements of maximum efficiency4 ,but since the nature and quality of gas necessarily vary with each city1 it is evident that an engine adjusted to develop a certain horse-power with a gas of a certain richness1 may not fulfil all expectations if it is fed with a gas less rich1 less pure1 hotter1 and the like4 ,the altitude also has some influence on the efficiency of the engine4 ,as it increases1 the density of the mixture diminishes2 that is to say1 for the same volume the engine is using a smaller amount4 ,from this it follows that a gas-engine ought to be adjusted as a general rule on the spot where it is to be used4 ,the fulfilment of this condition is particularly important in the case of explosion-engines1 because an advancement or retardation of only one-half a second in igniting the explosive mixture will cause a considerable loss in useful work4 ,from this it would follow that gas-engines should be periodically inspected in order that they may operate with the highest efficiency and economy4 ,as in the case of steam-engines1 it is advisable to take indicator records which afford conclusive evidence of the perturbations to which every engine is subject after having run for some time4 ,most gas-engine users either have no indicating instruments at their disposal or else are not sufficiently versed in their employment and the interpretation of their records to study perturbations by their means4 ,for this reason the advice of experts should be sought1--men who understand the meaning of the diagrams taken and who are able by their means to effect a considerable saving in gas4 ,,chapter ,,viii ,,how ,,to ,,start ,,an ,,engine--,,preliminary ,,precautions ,the first step which is taken in starting an engine driven by street-gas is1 naturally1 the opening of the meter-cock and the valves between the meter and the engine4 ,when the gas has reached the engine1 the rubber bags will swell up and the anti-pulsator diaphragm will be forced out4 ,the drain-cock of the gas-pipe is then opened4 ,in order to ascertain whether the flow of gas is pure1 a match is applied to the outlet of the cock4 ,the flame is allowed to burn until it changes from its original blue color to a brilliant yellow4 ,if the hot-tube system of ignition be employed1 the ,bunsen burner is ignited1 care being taken that the flame emerging from the tube is blue in color4 ,if necessary the admission of air to the burner is regulated by the usual adjusting-sleeve4 ,a white or smoky flame indicates an insufficient supply of air to the burner4 ,a characteristic sooty odor is still other evidence of the same fact4 ,sometimes a white flame may be produced by the ignition of the gas at the opening of the adjusting-sleeve4 ,a blue or greenish flame is that which has the highest temperature and is the one which should1 therefore1 be obtained4 ,about five or ten minutes are required to heat up the tube1 owing to the material of which it is made4 ,when the proper temperature has been attained the tube becomes a dazzling cherry red in color4 ,while the tube is being heated up1 it is well to determine whether the engine is properly lubricated and all the cups and oil reservoirs are duly filled up4 ,the cotton waste of the lubricators should be properly immersed1 and the drip lubricators examined to determine whether they are supplying their normal quantity of oil4 ,the regulating-levers of the valves should be operated in order to ascertain whether the valves drop upon their seats as they should4 ,the stem of the exhaust-valve should be lubricated with a few drops of petroleum4 ,if the ignition system employed be of the electric type1 with batteries and coils1 tests should be made to determine whether the current passes at the proper time on completing the circuit with the contact mounted on the intermediary shaft4 ,this contact should produce the characteristic hum caused by the operation of the coil4 ,if a magneto be used in connection with the ignition apparatus1 its inspection need not be undertaken whenever the engine is started1 because it is not so likely to be deranged4 ,still1 it is advisable1 as in the case of ignition by induction-coils1 to set in position the device which retards the production of the spark4 ,this precaution is necessary in order to avoid a premature explosion1 liable to cause a sharp backward revolution of the fly-wheel4 ,after the ignition apparatus and the lubricators have been thus inspected1 the engine is adjusted with the piston at the starting position1 which is generally indicated by a mark on the cam-shaft4 ,the starting position corresponds with the explosion cycle and is generally at an angle of #dj to #fj degrees formed by the crank above the horizontal and toward the rear of the engine4 ,the gas-cock is opened to the proper mark1 usually shown on a small dial4 ,if there be no mark1 the cock is slowly opened in order that no premature explosion may be caused by an excess of gas4 ,the steps outlined in the foregoing are those which must be taken with all motors4 ,each system1 however1 necessitates peculiar precautions1 which are usually given in detailed directions furnished by the builder4 ,as a general rule the engines are provided on their intermediary shafts with a relief or half-compression cam4 ,by means of this cam the fly-wheel can be turned several times without the necessity of overcoming the resistance due to complete compression4 ,care should be taken1 however1 not to release the cam until the engine has reached a speed sufficient to overcome this resistance4 ,engines of considerable size are commonly provided with an automatic starting appliance4 ,in order to manipulate the parts of which this appliance is composed1 the directions furnished by the manufacturer must be followed4 ,particularly is this true of automatic starters comprising a hand-pump by means of which an explosive mixture is compressed1--true because in the interests of safety great care must be taken4 ,the tightness and free operation of the valves or clacks which are intended to prevent back firing toward the pump should be made the subject of careful investigation4 ,otherwise1 the piston of the pump is likely to receive a sudden shock when back firing occurs4 ,when the engine has been idle for several days1 it is advisable1 before starting1 to give it several turns 7without gas7 in order to be sure that all its parts operate normally4 ,the same precaution should be taken in starting an engine1 if a first attempt has failed1 in order to evacuate imperfect mixtures that may be left in the cylinder4 ,before this test is made1 the gas-cock should1 of course1 be closed in order to prevent an untimely explosion4 ,it is advisable in starting an engine not to bend the body over the ignition-tube1 because the tube is likely to break and to scatter dangerous fragments4 ,under no condition whatever should the fly-wheel be turned by placing the foot upon the spokes4 ,all that should be done is to set it in motion by applying the hand to the rim4 ,care ,during ,operation4--,when the engine has acquired its normal speed1 the governor should be looked after in order that its free operation may be assured and that all possibility of racing may be prevented4 ,after the engine has been running normally for a time1 the cocks of the water circulation system should be manipulated in order to adjust the supply of water to the work performed by the engine4 ,in other words the cylinder should be kept hot1 but not burning1 as previously explained in the paragraph in which the water-jacket is discussed4 ,the maintenance of a suitable temperature is extremely important so far as economy is concerned4 ,all the bearings should be inspected in order that hot boxes may be obviated4 ,stopping the ,engine4--,the steps to be taken in stopping the engine are the following3 #a4 ,stopping the various machines driven by the engine1--a practice which is followed in the case of all motors2 #b4 ,throwing out the driving-pulley of the engine itself1 if there be one2 #c4 ,closing the cock between the meter and the gas-bags in order to prevent the escape of gas and the useless stretching of the rubber of the bags or of the anti-pulsating devices2 #d4 ,actuating the half-compression or relief cam as the motor slows down1 in order to prevent the recoil due to the compression2 #e4 ,closing the gas-admission cock2 #f4 ,shutting off the supply of oil of free flowing lubricators1 and lifting out the cotton from the others4 ,if the engine be used to drive a dynamo1 particularly a dynamo provided with metal brushes1 the precaution should be taken of lifting the brushes before the engine is stopped in order to prevent their injury by a return movement of the armature-shaft2 #g4 ,shutting off the cooling-water cock if running water is used4 ,if the engine is exposed to great cold1 the freezing of the water in the jacket is prevented while the engine is at rest1 either by draining the jacket entirely1 or by arranging a gas jet or a burner beneath the cylinder for the purpose of causing the water to circulate4 ,if such a burner be used the cocks of the water supply pipe should1 of course1 be left open4 ,,chapter ,,ix ,,perturbations ,,in ,,the ,,operation ,,of ,,engines ,,and ,,their ,,remedy ,in this chapter will be discussed certain perturbations which affect the operations of gas-engines to a more marked degree than lack of care in their construction4 ,in previous chapters defects in operation due to various causes have been dwelt upon1 such as objectionable methods in the construction of an engine1 ill-advised combination of parts1 defects of installation1 and the like2 and an attempt has been made to determine in each case the conditions which must be fulfilled by the engine in order to secure efficiency and economy at a normal load4 ,difficulties in ,starting4--,the preliminary precautions to be taken in starting an engine having been indicated1 it is to be assumed that the advice given has been followed4 ,nevertheless various causes may prevent the starting of the engine4 ,faulty ,compression4--,defective compression1 as a general rule1 prevents the ignition of the explosive mixture4 ,whether or not the compression be imperfect can be ascertained by moving the piston back to the period corresponding with compression1 in other words1 that position in which all valves are closed4 ,if no resistance be encountered1 it is evident that the air or the gaseous mixture is escaping from the cylinder by way of the admission-valve1 the exhaust-valve1 or the piston4 ,the valves1 ordinarily seated by springs1 may remain open because their stems have become bound1 or because some obstruction has dropped in between the disk and the seat4 ,in a worn-out or badly kept engine the valves are likely to leak4 ,if that be the case grinding is the only remedy4 ,if a valve be clogged1 which becomes sufficiently evident by manipulating the controlling levers1 it is necessary simply to clean the stem and its guides in order to remove the caked oil which accumulates in time4 ,if the engine be new1 the binding of the valve-stems is often caused by insufficient play between the stems and their guides4 ,should this prove to be the case1 the defect is remedied by rubbing the frictional surface of the stem with fine emery paper and by lubricating it with cylinder-oil4 ,the exhaust-valve1 however1 should be lubricated only with petroleum4 ,it is not unlikely that the exhaust-valve may leak for two other reasons4 ,in the first place1 the tension of the spring which serves to return the valve may have lessened and may be insufficient to prevent the valve from being unseated during suction4 ,again1 the screw or roller serving as a contact between the lever and the valve-stem1 may not have sufficient play1 so that the lengthening of the stem on account of its expansion may prevent the valve from falling back on its seat4 ,the first-mentioned defect is remedied by renewing the spring1 or by the provision of an additional spring or of a counterweight in order to prevent the stoppage of the motor4 ,the second defect can be remedied by regulating the contact4 ,leakage past the piston may be caused by the breaking of one or more rings1 by wear or binding of the rings1 or by wear or binding of the cylinder4 ,the whistling caused by the air or the mixture as it passes back proves the existence of this fault4 ,presence of ,water in the ,cylinder4--,it may sometimes happen that water may find its way into the cylinder with the gas by reason of the bad arrangement of the piping4 ,it may also happen that water may enter the cylinder through the water-jacket joint4 ,again1 the presence of water in the cylinder may be due to condensation of the steam formed by the chemical union of the hydrogen of the gas and the oxygen of the air1 which condensation is caused by the cool walls of the cylinder4 ,the water may sometimes accumulate in the exhaust pipe and box1 when they have been improperly drained1 and may thus return to the cylinder4 ,whatever may be its cause1 however1 the presence of water in the cylinder impedes the starting of the engine1 because the gases resulting from the explosion are almost spontaneously chilled1 thereby diminishing the working pressure4 ,if electric ignition be employed1 drops of water may be deposited between the contacts1 thereby causing short circuits which prevent the passing of the spark4 ,if there be no drain-cock on the cylinder1 the difficulty of starting the engine can be overcome only by ceaseless attempts to set it in motion4 ,the leaky condition of a joint as well as the presence of a particle of gravel in the cylinder-casting1 through which the water can pass from the jacket1 is attested by the bubbling up of gas in the water-tank at the opening of the supply tube4 ,these bubbles are caused by the passage of the gas through the jacket after the explosion4 ,if such bubbles be detected1 the cylinder should be renewed or the defect remedied4 ,in order to obviate any danger1 the stop-cocks of the water-jacket1 which have already been described in a previous chapter1 should be closed while the engine is idle4 ,imperfect ,ignition4--,the difficulties encountered in starting an engine1 and caused by imperfect ignition1 vary in their nature with the character of the ignition system employed1 whether that system1 for example1 be of the electric1 or of the incandescent or hot tube type4 ,frequently it happens that in starting an engine a hot tube may break4 ,if the tube be of porcelain the accident may usually be traced to improper fitting or to the presence of water in the cylinder4 ,if the tube be of metal1 its breaking is caused usually by a weakening of the metal through long use--an accident that occurs more often in starting the engine than in normal operation1 because the explosions at starting are more violent1 owing to the tendency of the supply-pipes to admit an excess of gas at the beginning4 ,a misfire arising from a faulty tube in starting may be caused by an obstruction or by leaks at the joints or in the body of the tube itself1 thereby allowing a certain quantity of the mixture to escape before ignition4 ,this defect in the tube is usually disclosed by a characteristic whistling sound4 ,a tube may leak either at the bottom or at the top4 ,in the first case1 starting is very difficult1 because the part of the mixture compressed toward the tube will escape through the opening before it reaches the incandescent zone4 ,in the second case1 ignition may be simply retarded to so marked an extent that a sufficient motive effect cannot be produced4 ,an example of this retardation1 artificially produced to facilitate the starting and to obviate premature explosions1 is found in a system of ignition-tubes provided with a small cock or variable valve 7,figs4 #gd and #ge74 ,illustration3 ,,fig4 #gd4 ,illustration3 ,,fig4 #ge4--;,ignition-tubes provided with needle valves to facilitate starting4 ,the mere enumeration of defects caused by leakage is sufficient to indicate the remedy to be adopted4 ,it may be well to recall in this connection the important part played by the ignition-valve4 ,if it be leaky1 or if its free operation be impeded1 starting will always be difficult4 ,electric ,ignition by ,battery or ,magneto4--,if the electric ignition apparatus1 whatever may be the method by which the spark is produced1 be imperfect in operation1 the first step to be taken is to ascertain whether the spark is produced at the proper time1 in other words1 slightly after the dead center in the particular position given to the admission device at starting4 ,if a coil and a battery be employed1 it is advisable to remove the plug and to place it with its armature upon a well-polished metal surface to produce an electrical contact1 preventing1 however1 the contact of the binding post with this metallic surface4 ,the same method of inspection is adopted with the make-and-break apparatus of an electric magneto4 ,in both cases it should be ascertained whether or not there is any short-circuiting4 ,the contacts should be cleaned with a little benzine if they are covered with oil or caked grease4 ,if no spark is produced at the plug or at the make-and-break device it may be inferred that the wires are broken or that the generating apparatus is out of order4 ,a careful examination will indicate what measures are to be taken to cure the defects4 ,premature ,ignition4--,it has several times been stated that the moment of ignition of the gaseous mixture has a pronounced influence on the operation of gas-engines and upon their economy4 ,premature ignition takes place when there is a violent shock at the moment when the piston leaps from the rear dead center to the end of the compression stroke4 ,the violent effects produced are all the more harmful because they tend to overheat the interior of the engine and thereby to increase in intensity4 ,premature ignition may be due to several causes4 ,if a valveless hot tube be employed it may happen that the incandescent zone is too near the base4 ,if the tube be provided with a valve1 it very frequently happens that the valve leaks or that it opens too soon4 ,in the case of electric ignition1 the circuit may be completed before the proper time1 because of faulty regulation4 ,the suggestions made in the preceding chapters indicate the method of remedying these defects4 ,faulty ignition may have its origin not only in the method of ignition employed1 but also in excessive heating of the internal parts of the engine1 caused by continual overloading or by inadequate circulation of water4 ,passing to those cases of premature ignition of a special nature which are not due to any functional defect in the engine1 but which are purely accidental in origin1 such as the uncleanliness of the parts within the cylinder or the presence of some projecting part which becomes heated to incandescence during compression1 it should first be stated that these ignitions1 usually termed spontaneous1 often occur well in advance of the end of the compression stroke4 ,they are characterized by a more marked shock than that caused by ordinary premature ignition and usually result in bringing the engine to a complete stop in a very short time4 ,these spontaneous explosions counteract to such an extent the impulse of the compression period1 during which the piston is moving back1 that they have a tendency to reverse the direction in which the engine is running4 ,in such cases a careful inspection and a scrupulous cleaning of the cylinder and of the piston should be undertaken4 ,the bottom of the piston is particularly likely to retain grease which has become caked1 and which is likely to become heated to incandescence and spontaneously to ignite the explosive mixture4 ,untimely ,detonations4--,the sound produced by the explosions of a normally operating engine can hardly be heard in the engine-room4 ,untimely detonations are produced either at the exhaust1 or in the suction apparatus1 near the engine itself4 ,these detonations are noisier than they are dangerous2 still1 they afford evidence of some fault in the operation which should be remedied4 ,detonations produced at the exhaust are caused by the burning of a charge of the explosive mixture in the exhaust-pipe1 which charge1 for some reason1 has not been ignited in the cylinder1 and has been driven into the exhaust-pipe1 where it catches fire on coming into contact with the incandescent gases discharged from the cylinder after the following explosion4 ,detonations produced in the suction apparatus of the engine1 which apparatus is either arranged in the base itself or in a separate chest1 are often noisier than the foregoing4 ,they are caused by the accidental backward flowing of the explosive mixture1 and by its ignition outside of the cylinder4 ,the accident may be traced to three causes3 #a4 ,the suction-valve of the mixture may not be tight and may leak during the period of compression1 allowing a certain quantity of the mixture to pass into the suction-chest or into the frame4 ,when the explosion takes place in the cylinder that part of the mixture which has passed back is ignited1 as we have just seen1 thereby producing a very loud deflagration4 ,the obvious remedy consists in making the suction-valve tight by carefully grinding it4 #b4 ,it may happen that at the end of the exhaust stroke incandescent particles may remain in the cylinder1 which particles may consist of caked oil or may be retained by poorly cooled projections4 ,the result is that the mixture is prematurely ignited during the suction period4 #c4 ,the engine is so regulated1 particularly in the case of ,english-built engines1 as to effect what is technically called scavenging the products of combustion4 ,in order to obtain this result1 the mixture-valve is opened before the end of the exhaust stroke of the piston and the closing of the exhaust-valve4 ,owing to the inertia and the speed acquired by the products of combustion shot into the exhaust-pipe after explosion1 a lowering of the pressure is produced in the cylinder toward the end of the stroke1 causing the entrance of air by the open admission-valve and consequently effecting the scavenging of the burnt gases1 part of which would otherwise remain in the cylinder4 ,it is evident that if a charge of the mixture has not been normally exploded1 either because its constituents have not been mingled in the proper proportion1 or because the ignition apparatus has missed fire1 this charge at the moment of exhausting will pass out of the cylinder without any acquired speed1 and will flow back in part at the end of the exhaust stroke past the prematurely opened admission-valve1 thereby lodging in the air suction apparatus4 ,despite the suction which takes place immediately following the re-entrance of the gas into the cylinder1 a certain quantity of the mixture is still confined in the suction-pipe and its branches1 where it will catch fire at the end of the exhaust stroke after the opening of the mixture-valve4 ,in order to avoid these detonations it is necessary simply to see to it that the mixture is regularly ignited4 ,this is accomplished by mixing the gas and air in proper proportions or by correcting the ignition time4 ,retarded ,explosions4--,retarded explosions considerably reduce the power which an engine should normally yield1 and sensibly increase the consumption4 ,they are due to three chief causes3 7#a71 faulty ignition2 7#b71 the poor quality of the mixture2 7#c71 compression losses4 ,the existence of the defect cannot be ascertained with any certainty without the use of an indicator or of some registering device which gives graphic records4 ,nevertheless1 it is possible in some degree to detect retarded explosions1 simply by observing whether there is a diminution in the power or an excessive consumption1 despite the perfect operation and good condition of all the engine parts4 ,in order to remedy the defect it should be ascertained if the compression is good1 if the supply of gas is normal1 and if the conditions under which the mixture of air and gas is produced have not been changed4 ,lastly1 the ignition apparatus is gradually adjusted to accelerate its operation until a point is reached when1 after explosion1 shocks are produced which indicate an excessive advance4 ,the ignition apparatus is then adjusted to a point slightly ahead of the corresponding position4 ,recalling the descriptions already given of the various systems of ignition1 the manner of regulating the moment of ignition in each case may be summarized as follows3 #a4 ,for the valveless incandescent tube1 provided with a burner the position of which can be varied1 ignition can be accelerated by bringing the burner nearer to the base4 ,retardation is effected by moving the burner away from the base4 #b4 ,in the case of the incandescent tube of the fixed burner type1 the moment of ignition will depend upon the length of the tube4 ,the retardation will be greater as the tube is shorter1 and vice versa4 #c4 ,if the tube be provided with an ignition-valve1 the time of ignition having been regulated by the maker1 regulation need not be undertaken except if the valve-stem be worn or the controlling-cam be distorted4 ,if these defects should be noted1 the imperfect parts should be repaired or renewed4 #d4 ,in electric igniters the controlling apparatus is generally provided with a regulating device which may be manipulated during the operation of the motor4 ,if the manual adjustment of the regulating apparatus be unproductive of satisfactory results1 it is advisable to ascertain whether the spark is being produced normally4 ,before the engine has come to a stop1 one of the valve-casings is raised1 and through the opening thus produced it is easily seen whether the spark is of sufficient strength1 the engine in the meanwhile being turned by hand4 ,care should always be taken to purge the cylinder of the gas that it may contain1 in order to prevent dangerous explosions4 ,if the spark should prove to be too feeble1 or if there be no spark at all1 despite the fact that every part of the mechanism is properly adjusted1 it may be inferred that the fault lies with the current and is caused by #a4 ,imperfect contact with the binding-posts1 with the conducting wire1 or with the contact-breaking members2 #b4 ,a short circuit in one of the dismembered pieces2 #c4 ,the presence of a layer of oil or of caked grease forming an insulator1 injurious to induction1 between the armature and the magnets2 #d4 ,a deposit of oil or moisture on the contact-breaking parts2 #e4 ,the exhaustion of the magnets1 which1 however1 occurs only after several years of use1 except when the magneto has been subjected for a long time to a high temperature4 ,the mere discovery of any of these defects sufficiently indicates the means to be adopted in remedying them4 ,lost ,motion in ,moving ,parts4--,lost motion of the moving parts is due to structural errors4 ,its cause is to be found in the insufficient size of the frictional bearing surfaces1 and improper proportioning of shafts1 pins1 and the like4 ,the result is a premature wear which cannot be remedied4 ,imperfect adjustment1 lack of care1 and bad lubrication1 may also hasten the wear of certain parts4 ,this wear is manifested in shocks1 occurring during the operation of the engine1--shocks which are particularly noticeable at the moment of explosion4 ,besides the inconveniences mentioned1 wearing of the gears and of the moving parts leads to derangement of the power-transmitting members4 ,so far as the admission and exhaust valves are concerned1 the wearing of the cams1 rollers1 and lever-pivots is evidenced by a retardation in the opening of these valves and an acceleration in their closing4 ,the ignition1 whatever may be the system employed1 is affected by lost motion and is retarded4 ,the engine appreciably loses in power1 and its consumption becomes excessive4 ,overheated ,bearings4--,apart from the imperfect adjustment of a member1 it may happen that the bushings of the main bearings of the ends of the connecting-rod1 and of the piston-pivot1 may become heated because of excessive play1 or of too much tightening1 or of a lack of oil1 or of the employment of oil of bad quality4 ,the overheating may lead to the binding of frictional surfaces and even to the fusion of bushings if they be lined with anti-friction metal4 ,in order to avoid the overheating of parts1 it is advisable1 while the engine is running1 to touch them from time to time with the back of the hand4 ,as soon as the slightest overheating is felt1 the temperature may be lowered often by liberal oiling4 ,if this be inadequate and if for special reasons it is impossible to stop the engine1 the overheated part may be cooled by spraying it with soapy water4 ,if the overheating has not been detected or reduced in time1 a characteristic odor of burnt oil will be perceived1 accompanied by smoke4 ,the part overheated will then have attained a temperature so high that it cannot be touched with the hand4 ,should this occur1 it is inadvisable to employ oil1 because it would immediately burn up and would only aggravate the conditions4 ,cotton waste should be carefully applied to the overheated member1 and gradual spraying with soapy water begun4 ,in special cases where the lubricating openings or channels are not likely to be obstructed1 a little flowers of sulphur may be added to the oil1 if this be very fluid4 ,castor oil may also be successfully employed4 ,if the binding of the rubbing surfaces should prevent the reduction of the overheated member's temperature1 the engine must necessarily be stopped1 and the parts affected detached4 ,all causes of binding are removed by means of a steel scraper4 ,the surfaces of the bushings and of the shaft which they receive are smoothed with a soft file and then polished with fine emery paper4 ,before the parts are replaced1 the precaution of ascertaining whether they touch at all points should be taken4 ,careful inspection and copious lubrication should1 of course1 be undertaken when the engine is again started4 ,overheating of the ,cylinder4--,the overheating of the cylinder may be due to a complete lack of water in the jacket or to an accidental diminution in the quantity of water supplied4 ,if this discovery is made too late1 and if the cylinder has reached a very high temperature1 the circulation of the water should not be suddenly re-established1 because of the liability of breaking the casting4 ,it is best to stop the engine and to restore the parts to their normal condition4 ,it is well to recall at this point that if the calcareous incrustation of the water-jacket or the branch pipes should hinder the free circulation of water1 cleaning is1 of course1 necessary4 ,the jacket may be washed several times with a twenty per cent4 solution of hydrochloric acid4 ,after this treatment the jacket should1 of course1 be rinsed with fresh water before the piping of the water-circulating apparatus is again connected4 ,overheating of the ,piston4--,if the overheating of the piston is not due to faulty adjustment1 it may be caused by lack of oil or to the employment of a lubricant not suitable for the purpose4 ,in a previous chapter the importance of using a special oil for cylinder lubrication has been insisted upon4 ,the overheating of the piston can also result from that of the piston-pin4 ,should this be the case it is advisable to stop the engine1 to ascertain the condition and the degree of lubrication of this member and its bearing4 ,overheating of the piston is manifested by an increase of the temperature of the cylinder at the forward end4 ,if this overheating be not checked1 binding of the piston in the cylinder is likely to result4 ,smoke ,arising from the ,cylinder4--,this is generally a sign either of overheating1 which causes the oil to evaporate1 or of an abnormal passage of gas1 caused by the explosion4 ,abnormal passage of gas may result from wear or from distortion of the cylinder1 or from wear or breakage of the piston-rings4 ,the result is always the overheating of the cylinder and a reduction in compression and power4 ,if the engine is well kept and shows no sign of wear1 leakage may be caused simply by the fouling of the piston-rings1 which then adhere in their grooves and have but insufficient play4 ,this defect is obviated by cleaning the rings in the manner explained in ,chapter ,,vii4 ,lubrication is faulty when the quantity of lubricant supplied is either insufficient or too abundant1 or when the oils employed are of bad quality4 ,it has already been shown that insufficient lubrication and the utilization of bad oils leads to the overheating of the moving parts4 ,insufficient lubrication may be caused by imperfect operation of the lubricators1 or1 particularly during cold weather1 by too great a viscosity or congelation of the oil4 ,if a lubricator be imperfect in its operation1 the condition of its regulating mechanism should be ascertained1 if it has any1 and an examination made to discover any obstruction in the oil-ducts4 ,such obstructions are very likely to occur in new devices which have been packed in cotton waste or excelsior1 with the result that the particles of the packing material often find their way into openings4 ,an oil may be bad in quality because of its very nature1 or because of the presence of foreign bodies4 ,in either case an oil of better quality should be substituted4 ,the freezing of oil by intense cold may be retarded by the addition of ordinary petroleum to the amount of #aj to #bj per cent4 ,an excess of oil in the bearings results simply in an unnecessary waste of lubricant1 and the splashing of oil on the engine and about the room4 ,if too much oil be used in the cylinder1 grave consequences may be the result2 for a certain quantity of the oil is likely to accumulate within the cylinder1 where it burns and forms a caky mass that may be heated to incandescence and prematurely ignite the explosive mixture4 ,especially in producer-gas engines is an excess of cylinder-lubricant likely to cause such accidents4 ,indeed1 the temperature of explosion not being as high as in street-gas engines1 the excess oil cannot be so readily removed with certainty by evaporation or combustion4 ,on the other hand1 the compression of the mixture being generally higher1 premature ignition is very likely to occur4 ,back ,pressure to the ,exhaust4--,how the pipes and chests for the exhaust should be arranged in order not to exert a harmful influence on the motor has already been explained4 ,even if the directions given have been followed1 however1 the exhaust may not operate properly from accidental causes4 ,among these causes may be mentioned obstructions in the form of foreign bodies1 such as particles of rust1 which drop from the interior of the pipes after the engine has been running for some time and which1 accumulating at any place in the pipe1 are likely to clog the passage4 ,furthermore1 the products of combustion may contain atomized cylinder oil which finds its way into the exhaust-pipe4 ,this oil condenses on the walls of the elbows and bends of the pipe in a deposit which1 as it carbonizes1 is converted into a hard cake and which reduces the cross-section of the passage1 thereby constituting a true obstacle to the free exhaust of the gases4 ,these various defects are manifested in a loss in engine power as well as in an abnormal elevation of the temperature of the parts surrounding the exhaust opening4 ,sudden ,stops4--,sudden stops are occasioned by faulty operation of the engine1 and by imperfect fuel supply4 ,among the first class the chief causes to be mentioned are the following3 #a4 ,overheating1 which has already been discussed and which may block a moving part4 #b4 ,defective ignition4 #c4 ,binding of the admission-valve or of the exhaust-valve1 preventing respectively suction or compression4 #d4 ,the breaking or derangement of a member of the distributing mechanism4 #e4 ,a weakening of the exhaust-valve spring1 so that the valve is opened by the suction of fresh quantities of mixture4 ,these faults are due to carelessness and improper inspection of the engine4 ,so far as the fuel supply of the engine is concerned1 the causes of stoppage will vary if street-gas or producer-gas be employed4 ,in the former case the difficulty may be occasioned by the improper operation of the meter1 by the formation of a water-pocket in the piping1 by the binding of an anti-pulsator valve1 by the derangement of a pressure-regulator1 or by a sudden change in the gas pressure when no pressure-regulator is employed4 ,if producer-gas be used1 stoppages may be occasioned by a sudden change in the quality1 quantity1 or temperature of the gas4 ,these defects will be examined in detail in the chapter on ,gas-,producers4 ,,chapter ,x ,,producer-,,gas ,,engines ,thus far only street-gas or illuminating-gas engines have been discussed4 ,if the engine employed be small--#aj to #ae horse-power1 for instance--street-gas is a fuel1 the richness1 purity and facility of employment of which offsets its comparatively high cost4 ,but the constantly increasing necessity of generating power cheaply has led to the employment of special gases which are easily and cheaply generated4 ,such are the following3 ,blast-furnace gases1 ,coke-oven gases1 ,fuel-gas proper1 ,mond gas1 ,mixed gas1 ,water-gas1 ,wood-gas4 ,the practical advantages resulting from the utilization of these gases in generating power were hardly known until within the last few years4 ,the many uses to which these gases have been applied in ,europe since #aijj have definitely proved the industrial value of producer-gas engines in general4 ,the steps which have led to this gradually increasing use of producer-gas have been learnedly discussed and commented upon in the instructive works and publications of ,aime ,witz1 ,professor in the ,faculty of ,sciences of ,lille1 in those of ,dugald ,clerk1 of ,london1 ,f4 ,grover1 of ,leeds1 and ,otto ,gueldner1 of ,munich1 and in those of the ,american authors1 ,goldingham1 ,hiscox1 ,hutton1 ,parsell and ,weed1 etc4 ,the new tendencies in the construction of large engines may be regarded as an interesting verification of the forecasts of these men--forecasts which coincide with the opinion long held by the author4 ,aime ,witz has always been an advocate of high pressures and of increased piston speed4 ,english builders who made experiments in this direction conceded the beneficial results obtained2 but while they increased the original pressure of #bh to #dc pounds per square inch employed five or six years ago to the pressure of #he to #ajj pounds per square inch nowadays advocated1 the ,germans1 for the most part1 have adopted1 at least in producer-gas engines1 pressures of #aad to #agj pounds per square inch and more4 ,high ,compression4--,in actual practice1 the problem of high pressures is apparently very difficult of solution1 and many of the best firms still seem to cling to old ideas4 ,the reason for their course is1 perhaps1 to be found in the fact that certain experiments which they made in raising the pressures resulted in discouraging accidents4 ,the explosion-chambers became overheated2 valves were distorted2 and premature ignition occurred4 ,because the principle underlying high pressures was improperly applied1 the results obtained were poor4 ,high pressures cannot be used with impunity in cylinders not especially designed for their employment1 and this is the case with most engines of the older type1 among which may be included most engines of ,english1 ,french1 and particularly of ,american construction4 ,in ,american engines notably1 the explosion-chamber1 the cylinder and its jacket1 are generally cast in one piece1 so that it is very difficult to allow for the free expansion of certain members with the high and unequal temperatures to which they are subjected 7,fig4 #bb74 ,some builders have attempted to use high pressures without concerning themselves in the least with a modification of the explosive mixture4 ,the result has been that1 owing to the richness of the mixture1 the explosive pressure was increased to a point far beyond that for which the parts were designed4 ,sudden starts and stops in operation1 overheating of the parts1 and even breaking of crank-shafts1 were the results4 ,the engines had gained somewhat in power1 but no progress had been made in economy of consumption1 although this was the very purpose of increasing the compression4 ,high pressures render it possible to employ poor mixtures and still insure ignition4 ,a quality of street-gas1 for example1 which yields one horse-power per hour with #ag4e cubic feet and a mixture of #a part gas and #h of air compressed to #gh pounds per square inch1 will give the same power as #ad cubic feet of the same gas mixed with #ab parts of air and compressed to #aga pounds per square inch4 ,scavenging of the cylinder1 a practice which engineers of modern ideas seem to consider of much importance1 is better effected with high pressures1 for the simple reason that the explosion-chamber1 at the end of the return stroke1 contains considerably less burnt gases when its volume is smaller in proportion to that of the cylinder4 ,in impoverishing the mixture to meet the needs of high pressures1 the explosive power is not increased and in practice hardly exceeds #cfe to #dbg pounds per square inch4 ,with the higher pressures thus obtained there is consequently no reason for subjecting the moving parts to greater forces4 ,illustration3 ,,fig4 #gf4--,method of cooling the cylinder-head4 ,cooling4--,the increase in temperature of the cylinder-head and of the valves1 due wholly to high compression1 is perfectly counteracted by an arrangement which most designers seem to prefer1 and which1 as shown in the accompanying diagram 7,fig4 #gf71 consists in placing the mixture and exhaust-valves in a passage forming a kind of antechamber completely surrounded by water4 ,the immediate vicinity of this water assures the perfect and equal cooling of the valve-seats4 ,this arrangement1 while it renders it possible to reduce the size of the explosion-chamber to a minimum1 has the additional mechanical advantage of enabling the builder to bore the seats and valve-guides with the same tool1 since they are all mounted on the same line4 ,from the standpoint of efficiency1 the design has the advantage of permitting the introduction of the explosive mixture without overheating it as it passes through the admission-valve1 which obtains all the benefit of the cooling of the cylinder-head1 literally surrounded as it is by water4 ,in large engines the cooling effect is even heightened by separately supplying the jackets of the cylinder-head and of the cylinder4 ,in engines of less power the top of the cylinder-head jacket is placed in communication with that of the cylinder1 so that the coldest water enters at the base of the head and1 after having there been heated1 passes around the cylinder in order finally to emerge at the top toward the center4 ,the water having been thus methodically circulated1 the useful effect and regularity of the cooling process is increased4 ,notwithstanding the care which is devoted to water circulation1 it is advisable to run the producer-gas engine colder than the older street-gas types1 in which the more economic speed is that at which the water emerges from the jacket at about a temperature of #ajd degrees ,f4 ,it would seem advisable to meet the requirements of piston lubrication by reducing to a minimum the quantity of heat withdrawn by the circulating water4 ,indeed1 the personal experiments of the author bear out this principle4 ,for street-gas engines1 however1 the cylinders should be worked at the highest possible temperature consistent with the requirements of lubrication4 ,it should not be forgotten that1 in large engines fed with producer-gas1 economy of consumption is a secondary consideration1 because of the low quantity of fuel required4 ,the cost1 moreover1 may well be sacrificed to that steadiness of operation which is of such great importance in large engines furnishing the power of factories2 for in such engines sudden stops seriously affect the work to be performed4 ,for this reason engine builders have been led to the construction of motors provided with very effective cooling apparatus4 ,since the circulation of the water around the explosion-chamber and the cylinder is not sufficient to counteract the rise of temperature1 it has become the practice to cool separately each part likely to be subjected to heat4 ,the seats of the exhaust-valves1 the valves themselves1 the piston1 and sometimes the piston-rod1 have been provided with water-jackets4 ,premature ,ignition4--,returning to the causes of the discouragements encountered by some designers who endeavored to use high pressures1 it has already been mentioned that premature ignition of the explosive mixture in cylinders not suited for high pressures is one reason for the bad results obtained4 ,an explanation of these results is to be found in the high theoretical temperature corresponding with great pressures and in the quantity of heat which must be absorbed by the walls of the explosion-chamber4 ,these two circumstances are in themselves sufficient to produce spontaneous ignition of excessively rich mixtures1 compressed in an overheated chamber unprovided with a sufficient circulation of water4 ,a third cause of premature ignition may also be found in the old system of ignition which1 in most ,english engines1 consists of a metallic or porcelain tube1 the interior of which communicates with the explosion-chamber1 an exterior flame being employed to heat the tube to incandescence4 ,in tubes of this type which are not provided with a special ignition-valve1 the time of ignition is dependent only on the moment when the explosive mixture1 driven into the tube1 comes into contact1 at the end of the compression stroke1 with the incandescent zone1 thereby causing the ignition4 ,this very empirical method leads either to an acceleration or retardation of the ignition1 depending upon the temperature of the tube1 the position of the red-hot zone1 its dimensions1 and the temperature of the mixture1 which is determined by the load of the engine4 ,although this system1 the only merit of which is its simplicity1 may meet the requirements of small engines1 there is not the slightest doubt that it is quite inapplicable to those of more than #bj to #be horse-power1 for in such engines greater certainty in operation is demanded4 ,even if only the more improved of the two types of hot-tube ignition be considered1 with or without valves1 it must still be held that they are inapplicable to high compression engines4 ,the ignition-valve is the part which suffers most from the high temperature to which it is subjected4 ,its immediate proximity to the incandescent tube1 and its contact with the burning gas when it flares up1 render it almost impossible to employ any cooling arrangement4 ,although with the exercise of great care it may work satisfactorily in engines of normal pressure1 it is evident that it cannot meet the requirements of high pressure engines1 because the temperature of the compressed mixture is such that the charge is certain to catch fire by mere contact with the overheated valve4 ,in industrial engines of small size1 premature ignition has little1 if any1 effect except upon silent operation and economic consumption4 ,this does not hold true1 however1 of large engines4 ,besides the inconveniences mentioned1 there is also the danger of breaking the cranks or other moving parts4 ,the inertia of these members is a matter of some concern1 because of their weight and of the linear speed which they attain in large engines4 ,some idea of this may be obtained when it is considered that in a producer-gas or blast-furnace-gas engine having a piston diameter of #bd inches and an explosive pressure of #bii pounds per square inch1 the force exerted at the moment of explosion is about #acb1jjj pounds4 ,naturally1 engine builders have adopted the most certain means of avoiding premature ignition and its grave consequences4 ,the method of ignition which at present seems to be preferred to any other for producer-gas is that employing a break-spark obtained with the magneto apparatus previously described4 ,some builders of large engines1 particularly desirous of assuring steadiness of running1 have provided the explosion-chamber with two independent igniters4 ,it may be that they have adopted this arrangement largely for the purpose of avoiding the inconveniences resulting from a failure of one of the igniters1 rather than for the purpose of igniting the mixture in several places so as to obtain a more uniform ignition and one better suited for the propagation of the flame4 ,the ,governing of ,engines4--,various methods have been adopted for the purpose of varying the motive power of an engine between no load and full load1 still preserving1 however1 a constant speed of rotation4 ,these methods consist in changing either the quantity or the quality of the mixture admitted into the cylinder4 ,thus it may happen that an engine may be supplied3 #a4 ,with a mixture constant in quality and in quantity2 #b4 ,with a mixture variable in quality and constant in quantity2 #c4 ,with a mixture constant in quality and variable in quantity4 #a4 ,mixture ,constant in ,quality and ,quantity4--,this method implies the use of the hit-and-miss system of admission1 in which the number of admissions and explosions varies1 while the value or the composition of each admitted charge remains as constant as the compression itself 7,fig4 #cd74 ,this system has already been referred to and its simplicity fully set forth4 ,by its use a comparatively low consumption is obtained1 even when the engine is not running at full load4 ,on the other hand1 it has the disadvantage of necessitating the employment of heavy fly-wheel to preserve cyclic regularity4 #b4 ,mixture ,variable in ,quality and ,constant in ,quantity4--,the governing system most commonly employed to obtain a mixture variable in quality and constant quantity is based upon the control of the gas-admission valve by means of a cam having a conical longitudinal section1 as shown in ,fig4 #ce4 ,this cam1 commonly called a conical cam1 is connected with a lever actuated from the governor4 ,as the lever swings under the action of the governor1 the cam is shifted along the half-speed shaft of the engine4 ,the result is that the gas-admission valve is opened for a longer or shorter period4 ,in another system a cylindrical valve is mounted between the chamber in which the mixture is formed and the gas-supply pipe1 the valve being carried on the same stem as the mixture-valve itself4 ,the cylindrical valve is displaced by the governor so as to vary the quantity of gas drawn in with relation to the quantity of air4 ,when the engines are fed with producer-gas the parts which have just been described should be frequently inspected and cleaned2 for they are only too easily fouled4 ,engines thus governed should be run at high pressure so as to insure the ignition of the producer-gas mixtures formed when the position of the cam corresponds with the minimum opening of the gas-valve4 ,powerful governors should be employed1 capable of overcoming the resistance offered by the cylindrical valve or the cam4 ,it may often happen that variations in the load of the engine render it necessary to actuate the air valve1 so as to obtain a mixture which will be ignited and exploded under the best possible conditions4 #c4 ,mixture ,constant in ,quality and ,variable in ,quantity4--,in supplying an engine with a mixture constant in quality and variable in quantity1 the compression does not remain constant4 ,the quantity of mixture drawn in by the cylinder may even be so far reduced that the pressure drops below the point at which ignition takes place4 ,for that reason engines of this type should be run at high pressures4 ,the variation of the quantity of mixture may be effected in various ways4 ,the simplest arrangement consists in mounting a butterfly-valve in the mixture pipe1 which valve is controlled by the governor and throttles the passage to a greater or lesser degree4 ,a very striking solution of the problem consists in varying the opening of the mixture-valve itself4 ,to attain this end the valve is moved by levers4 ,the point of application of one of these levers is displaced under the action of the governor so as to vary the travel of the valve within predetermined limits4 ,under these conditions a mixture of constant homogeneity is introduced into the cylinder1 so proportioned as to insure ignition even at low pressures4 ,illustration3 ,,fig4 #gf;a4--,governing system for producer-gas engines4 ,in recent experiments conducted by the author it was proved that with this governing system ignition still takes place even though the pressure has dropped to #dc pounds per square inch4 ,this system has the merit of rendering it possible to employ ordinary governors of moderate size1 since the resistance to be overcome at the point of application of the lever is comparatively small4 ,in the accompanying illustration the ,otto ,deutz system is illustrated4 ,,chapter ,,xi ,,producer-,,gas ,it may here be not amiss to point out the differences between illuminating gas and those gases which are called in ,english producer gases1 and in ,french poor gases1 because of their low calorific value4 ,street-,gas4--,this gas1 the composition of which varies with different localities1 has a calorific value1 which is a function of its composition1 and which varies from #e1jjj to #e1fjj calories per cubic meter 7#ai1hda to #bd1hif ,b4,t4,u4 per #ce4ca cubic feet7 measured at constant pressure and corrected to #j degrees ,c4 7#cb degrees ,f47 at a pressure of #gfj millimeters 7#bi4i inches of mercury1 or atmospheric pressure71 not including the latent heat of the water of condensation4 ,the following table gives the average volumetric composition of illuminating gas in various cities3 ,cities4 ,manches- ,new ,london4 ter4 ,york4 ,paris4 ,berlin4 ,hydrogen #dh #df #dj #eb #ej ,carbon monoxide #d #g #d #f #i ,methane #ch #ce #cg #cb #cc ,various hydrocarbons #d #f #g #f #e ,carbon dioxide #d #c #b ,nitrogen #e #b #h #d #a ,oxygen #a 444 #a 444 444 #ajj #ajj #ajj #ajj #ajj ,furthermore1 these constituents vary within certain limits4 ,this is also true of the calorific value4 ,experiments made by the author have demonstrated that in the same place at an interval of a few hours1 variations of approximately ten per cent4 occur4 ,composition of ,producer-,gases4--,the average chemical composition of producer-gases varies with the conditions under which they are generated and the nature of the fuel4 ,the following are the proportions of its constituents expressed volumetrically3 ,table ,headings-- ,a3 ,blast ,furnace4 ,b3 ,producer4 ,c3 ,mond4 ,d3 ,mixed 7,fichet74 ,e3 ,water 7,stache74 ,f3 ,wood 7,riche74 ,gas4 ,a4 ,b4 ,c4 ,d4 ,e4 ,f4 ,nitrogen and oxygen #fj #ei #db #ej #e #a ,carbon monoxide #bd #be #aa #bj #dj #bi ,carbon dioxide #ab #e #af #g #d #aa ,hydrocarbons #b #b #b #c #a #ae ,hydrogen #b #i #bi #bj #ej #dd #ajj #ajj #ajj #ajj #ajj #ajj ,calorific value in calories4 #iej #a1ajj #a1djj #a1cjj #b1djj #b1ifj ,average weight of a cubic meter in kilos #a4cj #a4a #a4jb #a4je #j4fhj #j4hbd ,or of a cubic foot in pounds #j4jjh #j4jjg #j4jjf #j4jjfh #j4jjdb #j4jjea ,blast-furnace gas has been used for generating power by means of gas-engines for about ten years4 ,at the present time it is used in engines of very high power1 a discussion of which engines more properly belongs to a work on metallurgy1 and has no place1 therefore1 in a manual such as this4 ,producer-gas1 in the true sense of the term1 is generated in special apparatus either under pressure or by suction in a manner to be described in the following chapters4 ,mond gas is produced in generators of the blowing or pressure type from bituminous coal1 necessitating the employment of special purifiers and permitting the collection of the by-products of the fractional distillation of the coal4 ,mond gas plants are1 therefore1 rather complicated and can be advantageously utilized only for large engines4 ,more exhaustive information can be obtained from the descriptions published by the builders of ,mond gas generators4 ,mixed gas is generated in apparatus arranged so that the retort is kept at a high temperature1 thereby producing a gas richer in hydrogen than that made by producers4 ,it should be observed that in practice the generators at present used yield a producer-gas1 the calorific value of which fluctuates between #a1jjj and #a1djj calories per cubic meter 7#c1ifh to #e1aeh ,b4,t4,u4 per #ce4ca cubic feet72 and the composition varies accordingly1 in the manner that has already been indicated in the tables for producer-gas and mixed gas4 ,there is no necessity1 therefore1 for drawing a distinction between these two qualities of gas4 ,water-gas should theoretically be composed of #ej per cent4 carbon monoxide and #ej per cent4 hydrogen1 resulting from the decomposition of steam by incandescent coal4 ,in practice1 however1 it contains a little nitrogen and carbon dioxide4 ,the gas is obtained from generators in which air is alternately blown in to fan the fire and then steam to produce gas4 ,water-gas is employed in soldering on account of its reducing properties and of the high temperature of its flame4 ,the great quantity of carbon monoxide which it contains renders it very poisonous and exceedingly dangerous1 because it is generated under pressure4 ,from the economical standpoint1 its generation is more expensive than that of producer-gas1 for which reason its employment in gas-engines is hardly of much value4 ,wood-gas1 the composition of which has already been given1 is generated in apparatus of the ,riche type1 the principle of which consists in heating a cast retort charged with any kind of fuel1 namely wood1 and vertically mounted on a masonry base4 ,this apparatus should be of particular interest to the proprietors of sawmills1 furniture factories1 and the like1 since it offers a means of using the waste products of their plants4 ,the relatively high proportion of carbon monoxide in producer-gas is objectionable from a hygienic standpoint1 so much so1 indeed1 that it has attracted the attention of manufacturers4 ,carbon monoxide1 the specific gravity of which is #j4ifg1 is a gas peculiarly poisonous and dangerous4 ,it cannot be breathed without baneful effects1 and is even more dangerous than carbonic-acid gas1 which eventually causes asphyxiation by reducing the quantity of oxygen in the air4 ,for this reason1 it is necessary to take the utmost precaution in efficiently and continuously ventilating the rooms in which the gas-generators and their accessories are installed4 ,this suggestion should be followed1 above all1 when the apparatus in question are installed in cellars and basements4 ,as a further precaution1 where the plant is rather large a workman should not be allowed to enter the generator room alone4 ,blowing-generators1 or those in which the gas is produced under pressure1 are more dangerous than suction-generators4 ,in the former a leaky joint may cause the vitiation of the surrounding air as the producer-gas escapes2 in the suction apparatus the same fault simply causes more air to be drawn in4 ,dr4 ,melotte recommends the following procedure in cases of carbon monoxide asphyxiation3 ,,carbon ,,monoxide ,,asphyxiation ,cases of poisoning by carbon monoxide are both frequent and dangerous4 ,the gas is extremely poisonous1 and all the more dangerous because it is odorless1 colorless and tasteless4 ,when it comes into contact with the blood1 it forms a combination so stable that it is reacted upon by the oxygen of the air only with difficulty4 ,it follows1 therefore1 that with each respiration of air charged with carbon monoxide1 a certain quantity of blood is poisoned4 ,in consequence of this1 there is a possibility of poisoning in open air4 ,symptoms4--,the symptoms observed will vary with the manner in which the blood has been poisoned4 ,there are two ways in which this poisoning can occur4 ,the one depends upon whether the atmosphere contains an excess of carbon monoxide2 the other whether the air breathed contains only traces of the gas4 ,gradual1 ,rapid ,asphyxiation4--,at first a vague sickness is felt1 rapidly followed by violent headaches1 vertigo1 anxiety1 oppression1 dimness of vision1 beating of the pulse at the temples1 hallucinations1 and an irresistible desire to sleep4 ,if at this stage the patient has a sufficient idea of danger to prompt him to open a window or door1 he will escape death4 ,in the second stage1 the victim's legs are paralyzed1 but he can still move his arms and his head4 ,the mind still preserves its clearness1 and in a measure assists the further process of asphyxiation because of its impotency4 ,then follow coma and death4 ,slow1 ,chronic ,asphyxiation4--,slow1 chronic asphyxiation is not infrequent4 ,its symptoms are often difficult to detect4 ,poisoning is manifested by weakness1 cephalalgia1 vomiting1 pallor1 general anemia1 lassitude1 and local paralysis4 ,if any of these symptoms appear in the men who work in the vicinity of the producers1 immediate steps should be taken to prevent the possibility of carbon monoxide asphyxiation4 ,,first ,,aid ,,in ,,cases ,,of ,,carbon ,,monoxide ,,poisoning ,it has already been stated that the oxygen of the air has no oxidizing effect upon blood contaminated by carbon monoxide4 ,only a liberal current of pure oxygen can oxidize the combination formed and render hematosis possible4 ,this liberal current can be obtained from an oxygen tank of the portable variety1 provided with a tube carrying at its free end a mask which is held over the mouth and the nostrils4 ,the absorption of gas takes place by artificial respiration1 which is effected in several ways4 ,the most practical of these are the ,sylvester and ,pacini methods4 ,sylvester ,method4--,the patient is laid on his back4 ,his arms are raised over his head and then brought back on each side of the body4 ,this operation is repeated fifteen times per minute approximately4 ,the method is very frequently employed and is excellent in its results4 ,the ,pacini ,method4--,four fingers are placed in the pit of the arm1 with the thumb on the shoulder4 ,the shoulder is then alternately raised and lowered1 producing a marked expansion of the chest4 ,this method is the more effective of the two4 ,the movements described are repeated fifteen to twenty times each minute very rhythmically4 ,one or the other of these two methods of treatment should be immediately applied in serious cases4 ,certain preliminary precautions should be taken in all cases1 however4 ,the patient should be carried to a well-ventilated and moderately heated room1 stripped of his clothes1 and warmed by water-bottles and heated linen4 ,reflex action should be excited1 the peripheral nervous system stimulated in order to contract the heart and the respiratory muscles1 and the precordial region cauterized4 ,in addition to this treatment1 the region of the diaphragm should be rubbed and pinched1 the skin rubbed1 cold showers given1 flagellations administered1 urtications 7whipping with nettles7 undertaken1 the skin and the mucous membranes excited1 the mucous membrane of the nose and of the pharynx titillated with a feather dipped in ammonia1 alcohol1 vinegar1 or lemon juice4 ,rhythmic traction of the tongue is effective when carried out as follows3 ,the tongue is seized with a forceps and kept extended by means of a coarse thread4 ,it is then pulled out from the mouth sharply and allowed to reenter after each traction4 ,these movements should be rhythmic and should be repeated fifteen to twenty times a minute4 ,all these efforts should be continued for several hours4 ,when the patient has finally been revived1 he should be placed in a warm bed4 ,stimulants such as wine1 coffee1 and the like should be administered4 ,if the head should be congested1 local blood-letting should be resorted to and four or six leeches applied behind the ears4 ,it should be borne in mind that the various steps enumerated are to be taken pending the arrival of a physician4 ,,impurities ,,of ,,the ,,gases ,most of the coal used in generating producer-gas contains sulphur4 ,sulphuretted hydrogen is thus produced1 which mixes with the gas and imparts to it its characteristic odor4 ,in some gas-generators1 purifiers are employed in which sawdust mixed with iron salts is utilized1 with the result that a combination is formed with the sulphuretted hydrogen1 thereby removing it from the producer-gas4 ,in other forms of generators a more summary method of purification is adopted1 so that traces of sulphuretted hydrogen still remain4 ,since this gas attacks copper1 the employment of this metal is not advisable for the following apparatus3 ,generator 7openings1 cock for testing the gas72 piping 7gas-pressure cocks1 drain and pet cocks72 engine 7gas-admission cock1 lubricating joint in the cylinder1 valves and cocks of the compressed-air starting-pipe74 ,the distillation of coal in generators results in the formation of ammonia gas4 ,this also has a corrosive action on copper and its alloys2 but owing to its great solubility1 it is eliminated by the waters of the scrubber and does not reach the engine4 ,,production ,,and ,,consumption ,the quantity of gas produced in most generators varies from #f4d to #h4b pounds per cubic foot of raw coal burnt in the generator4 ,the engine consumes per horse-power per hour #gj to #aae cubic feet of gas1 depending upon its richness4 ,,chapter ,,xii ,,pressure ,,gas-,,producers ,as we have already seen1 producer-gas as a fuel for engines may be generated in two kinds of apparatus1 the one operating under pressure1 and the other by suction4 ,dowson ,gas-,producers4--,the first pressure-generators were introduced by ,dowson of ,london and necessitated installations of quite a complicated nature4 ,later improvements made by the designers contributed much to the general employment of their system4 ,many installations varying from #ej to #ajj horsepower and more may be found in the ,united ,kingdom1 all of them made by ,dowson4 ,indeed1 for a long time the name of ,dowson was coupled with producer-gas itself4 ,the ,dowson system necessitates the utilization of anthracite or of comparatively hard coal1 such as that mined in ,wales and ,pennsylvania4 ,owing to the necessity of employing this special quality of coal the ,dowson system and the systems that sprang from it were burdened with cooling1 washing1 and purifying apparatus1 which complicated the installations to such an extent that they resembled gas works4 ,the generator that took the place of the retort was fed with air and steam1 blown in under pressure1 necessitating the employment of a boiler4 ,furthermore1 the production of the gas under pressure necessitated the use of a gasometer for its collection before it was supplied to the engine-cylinder4 ,such ,installations were evidently costly1 and were1 moreover1 difficult to maintain in proper working order4 ,nevertheless1 there are many cases in which they must be industrially employed4 ,illustration3 ,,fig4 #gg4--;,a complete ,dowson producer-gas plant4 ,illustration3 ,,fig4 #gh4--;,a ,simplex producer-gas plant4 ,among these may be cited works in which producer-gas is employed as a furnace fuel or as a soldering or roasting medium4 ,still other cases are those in which the producer-gas must be piped to some distance from a central generating installation to various engines1 in the manner rendered familiar in gas-lighting practice4 ,most pressure gas-generators have been copied from the original type invented by ,dowson4 ,these include a generator in which the gas is produced2 an injector fed by a boiler2 a fan or a compressor by means of which a mixture of steam and air is blown under the generator-furnace2 washing apparatus termed scrubbers2 gas-purifying apparatus2 and a gas-holder 7,fig4 #gg74 ,generators4--,the generator consists of a retort made of refractory clay1 vertically mounted1 and cylindrical or conical in form4 ,this retort is protected on its exterior by a metal jacket with an intermediate layer of sand which serves to reduce the heat lost by radiation4 ,the fuel is charged through the top of the retort1 which is provided with a double closure in order to prevent the entrance of air during the charging operation4 ,the generator rests on a grid arranged at the base of the retort1 upon which grid the ashes fall4 ,the outlet of the injector-pipe opens into the ash-pit1 and this injector constantly supplies a mixture of steam and air4 ,the mixture is generally superheated by passing it through a coil arranged in the fire-box of the boiler1 in the generator1 or in the outlet for burnt gases4 ,sometimes the air is subjected to a preliminary heating by recuperating in some way the waste heat of the apparatus4 ,the chief features in the arrangement of generators which have received the attention of manufacturers are the following3 ,good distribution of the fuel in charging2 easy descent of the fuel2 reduction of the destructive action of the clinkers on the walls2 means for cleaning the grate without interfering with the generation of gas2 prevention of leakage4 ,many devices have been employed to fulfil these requisites4 ,a perfect distribution of the fuel during charging is attained chiefly by the form of the hopper1 and of its gate1 which is generally conical4 ,in most apparatus the gate opens toward the interior of the generator1 and the inclination of its walls causes a uniform scattering of the fuel in the retort4 ,it is all the more necessary to disperse the fuel in this manner when the cross-section of the retort is small compared with its height4 ,the facility of the fuel's descent is dependent largely upon the nature and the size of the coal employed4 ,porous coal gives better results than dense and compact coal4 ,it is therefore preferable to employ screened coal free from dust in pieces each the size of a hazel-nut4 ,the various sections given to the interior1 including as they do cylindrical forms1 truncated at the summit or the base1 partially truncated toward the base and the like1 would lead to the conclusion that this question is not of the importance which some writers would have us believe4 ,still1 it must be considered that if the fuel drops slowly1 its prolonged detention within the walls of the hopper and its transformation into fusible slag may result in a disintegration of the refractory lining of the furnace4 ,the quantity of steam injected1 greater or less1 according to the nature of the fuel1 renders it possible to obtain friable slags and consequently to prevent grave injury to the retort4 ,red-ash coal is in general fusible1 containing as it does some iron4 ,its temperature of fusion varies between #a1hcb to #b1gcb degrees ,f4 ,cleanliness is most important so far as the operation of the generator is concerned4 ,it should be possible to scrape the generator during operation without changing the composition of the gas1 when the incandescent zone is chilled1 or an excess of air is introduced1 or the steam-injector be momentarily thrown out of operation4 ,mechanical cleaners with movable grates or revolving beds have the merit of causing the ashes to drop without interfering with the operation of the apparatus4 ,the same meritorious feature is characteristic of ash-pits having water-sealed joints4 ,pressure gas-generators need not be as perfectly gas-tight as suction apparatus4 ,leakage of gas1 which is usually manifested by a characteristic odor1 results in a loss of consumption and renders the air unfit to breathe4 ,a generator should be provided in its upper part with openings through which a poker can easily be introduced in order to shake up the fuel and to dislodge the clinkers which tend to form and which cause the principal defects in operation1 particularly with fuels that tend to swell1 cake1 and adhere to the furnace walls when heated4 ,many apparatus1 moreover1 are provided with lateral openings having mica panes through which the progress of combustion can be observed 7,fig4 #gi74 ,illustration3 ,,fig4 #gi4--;,fichet-,heurtey producer with rotating bed-plate4 ,air-,blast4--,the system by which air and steam are injected necessitates the employment of a steam-boiler of #ge pounds pressure4 ,this method of blowing1 which is rather complicated1 has the disadvantage of varying in feed with the pressure of the steam in the boiler1 which pressure is not easily maintained at a given number of pounds per square inch4 ,moreover1 when more or less resistance is offered by the fuel in the generator the quantity of air which is injected is likely to be diminished in quantity while the quantity of steam remains the same4 ,the result is a change in speed which follows from the modification of the proportions of the two elements4 ,for these reasons some manufacturers have resorted of late years to the employment of fans and blowers4 ,illustration3 ,,fig4 #hj4--,koerting blower4 ,blowers4--,the fans or blowers employed vary considerably in arrangement4 ,most of them are based on the ,koerting system 7,fig4 #hj71 and comprise essentially 7#a7 a tube through which the steam is supplied under pressure1 and 7#b7 a cylindro-conical blast-pipe4 ,the tube is placed in the axis of the blast-pipe at its outer opening4 ,as it escapes under pressure the steam is caught in the blast-pipe and draws with it a certain quantity of air1 which can be regulated4 ,it is important that these injection blowers should operate in such a manner that the pressure and the feed of air and steam can be controlled4 ,fans4--,mechanical blowers have the advantage of dispensing with the employment of steam under pressure and the consequent installation of a boiler 7,fig4 #gh74 ,driven by the engine itself or from some separate source of power1 these apparatus are easily placed in position1 require no great amount of attention1 and utilize but little energy4 ,they are either of the centrifugal type or of the rotary type1 exemplified in the ,root blower 7,fig4 #ha74 ,the latter system has the advantage of high efficiency1 and of enabling comparatively high pressures--#ai to #bg inches of water--to be attained1 which1 however1 are used only for special fuels1 such as lignite1 peat1 and the like4 ,the air supplied by the blower1 before reaching the fire-box1 is superheated1 either before or after it is charged with steam4 ,illustration3 ,,fig4 #ha4--,root blower4 ,compressors4--,in some installations air is supplied by compressor under the high pressure of #gj to #ij pounds per square inch1 and seem well adapted to the production of a gas of good quality4 ,moreover1 neither tar nor ammoniacal waters are produced4 ,the ,gardie producer may be considered typical of this class of apparatus 7,fig4 #hb74 ,the chief feature of this producer is to be found in simple washing and purifying apparatus4 ,it may be well to state here that the compression of air at high pressure occasions some complications1 and a considerable expenditure of power4 ,illustration3 ,,fig4 #hb4--;,gardie producer4 ,exhausters4--,some designers have invented devices which draw gas into the generator whence it is supplied to the engines1 these suction apparatus being connected with the blowers or used separately4 ,but with the exception of a few special instances1 such arrangements are not widely used--at least not for the production of motive power alone4 ,whatever may be the arrangement employed for the introduction of a mixture of air and steam under the grate of the generator1 the blast-pipe as a general rule discharges toward the center of the apparatus4 ,still1 in large producers it becomes desirable to provide a means for varying the quantity of air and steam within wide limits so as to regulate the heat of the fire4 ,for that reason several outlets are symmetrically arranged below the fuel4 ,illustration3 ,,fig4 #hc4--,sawdust purifier4 ,washing and ,purifying4--,in pressure producers the gas is generally washed and purified with much more care than in suction apparatus4 ,given a sufficient pressure1 the gas can be driven through the different apparatus and the spaces between the material which they contain without any difficulty4 ,the gases emerge from the generator highly heated1 and this heat is used either to warm the injection water or to generate the steam fed to the furnace4 ,the gases then enter the washing apparatus1 which most frequently consists of a succession of contrivances in which the gas is washed either by causing it to bubble up through the water1 or by subjecting it to superficial friction against a sheet of water1 or by systematically circulating it in a mass of continuously besprinkled inert material4 ,the object of washing is to remove the dust contained in the gas and to precipitate it in the form of a slime which can be removed by flushing4 ,illustration3 ,,fig4 #hd4--,moss or fiber purifier4 ,physical purification thus begun is completed by passing the gas through a filtering bed consisting of fiber1 sawdust1 or moss 7,figs4 #hc and #hd74 ,chemical purification if it is necessary1 is effected by means of calcium hydrate1 iron oxide1 or1 still better1 by a mixture of lime and iron sulphate4 ,this filtering material must necessarily be renewed after it is exhausted4 ,illustration3 ,,fig4 #he4--;,combined gas-holder and washer4 ,gas-,holder4--,the gas-holder is composed essentially of a tank and a bell4 ,sometimes1 for the purpose of simplifying the apparatus1 the tank is so arranged as to take the place of a washer or scrubber 7,fig4 #he74 ,the bell should be provided with mechanism which1 when the bell is full1 automatically diminishes or stops the generation of gas4 ,it is advisable to provide the bell with a blow or flap valve opening toward the interior4 ,if1 therefore1 it should happen that the gas supply is cut off while the engine still continues to run1 the suction of the engine will not draw the water from the tank of the gas-holder4 ,when engines are employed the horse-power of which does not exceed #ej1 it is sometimes customary to use the water of the tank 7placed at a higher elevation than the engine7 to cool the cylinder4 ,in this manner the cost of installing special reservoirs is saved4 ,if such an arrangement be employed1 however1 the quantity of water contained in the tank should be at least double that ordinarily contained in reservoirs4 ,if this precaution be not observed1 the water may become excessively heated and expand the gas in the bell4 ,the volume of the bell of the gas-holder should preferably be not less than about #c cubic feet per effective horse-power of the engine to be supplied4 ,under these circumstances the bell acts as a pressure-regulator1 assures a sufficient homogeneity of the remaining gas1 and renders it possible to supply the engine during the short intervals in which it is necessary to stop the blast to poke the fire4 ,but if the engine consumes #fj to #hj cubic feet of producer-gas per horse-power per hour1 the bell must be very much larger in size if the generation of gas is to be checked for some time4 ,it may be well to recall here that coal is not the only fuel which lends itself to the generation of gas suitable for driving engines1 but that some generators are able to utilize lignite1 peat1 and the like4 ,in others1 straw1 wood1 shavings and sawdust1 tannery waste1 and other organic matter is burnt with an efficiency very much higher than that which they would give in the fireboxes of steam-boilers4 ,illustration3 ,,fig4 #hf4--,otto ,deutz lignite-producer4 ,lignite and ,peat ,producers4--,lignite and peat generators 7,fig4 #hf7 cannot operate on the suction principle because of the resistance offered to the passage of gas by the layer of fuel4 ,this resistance is considerable and extremely variable4 ,consequently1 lignite and peat generators must operate on the pressure principle by utilizing a blast of air or a steam injector1 depending upon the amount of water contained in the lignite4 ,as a general rule a ,root blower operating at a pressure of #h to #bg inches of water1 depending upon the quality of the lignite1 is employed4 ,these generators are not to be recommended for powers less than #ej horse-power1 for the cost of the apparatus becomes too great4 ,the best lignite is that which1 after combustion1 leaves a fine ash and no agglomerated clinker4 ,lignite has the peculiarity of forming dust which ignites very easily when air is admitted into the generator4 ,for this reason the generator should not be scraped during operation1 in order to avoid the production of a flame which may escape from the apparatus4 ,the scrubber is simply a column without coke1 and is provided with an interior sprinkler4 ,the coke is too rapidly clogged with tar4 ,much of this tar is deposited in a chamber which precedes the gas-holder4 ,several quarts of tar may be tapped from the chamber daily4 ,the gas-holder serves merely to regulate the production of gas4 ,the pipes leading to the engine should be cleaned several times each month1 in order to remove the thin layer of tar which is deposited within them4 ,there are many kinds of lignite1 and the gas-generator should be constructed to meet the peculiar requirements of the variety employed4 ,the layer of fuel should be such in thickness that the gas as it emerges from the generator has a temperature of about #gg degrees ,f4 ,this is the temperature of the gas which leaves the scrubber in the case of anthracite-generators4 ,if the lignite contains much water1 the greater part is retained in the washer by the gas in the form of drops4 ,sometimes the water drips through the grate of the generator4 ,lignite-generators may also be operated with peat1 and even with town refuse1 with slight modifications4 ,the consumption per horse-power per hour is #c4c pounds of lignite containing #b1djj calories 7#i1dbd4i ,b4,t4,u474 ,in order to generate the same power with a boiler and steam-engine1 #h4h pounds would be required4 ,an engine driven unloaded with fuel furnished by a lignite-generator will consume #ej per cent4 of the weight of the fuel required at full load4 ,this depends upon the proportion of water contained in the lignite and on losses of heat by radiation from the generator4 ,in street-gas engines running without load1 the absorption is #bj per cent41 in anthracite-generators #dj per cent4 of the consumption at full load4 ,passing now to the utilization of wood1 of which something has already been said in ,chapter ,,xi1 two entirely distinct processes are successfully employed in apparatus of the ,riche type1 these processes depending upon the form of the wood used--whether1 in other words1 the wood be consumed in the form of sticks or blocks or in the form of chips1 sawdust1 bark1 and the like1 all of them the wastes of factories in which wood is used4 ,distilling-,producers4--,if the wood consists of logs1 it is burnt in a generator comprising a fire-box and a distilling retort4 ,the fire-box is charged with ordinary coal which serves to heat the retort to redness4 ,the wood is discharged through the top of the retort1 and the gas1 produced by the distillation1 escapes through the bottom and passes to the washing apparatus4 ,the base of the retort is heated to about #a1feb degrees ,f41 while at the top this temperature is reduced to #geb degrees ,f4 ,the wood thus treated is transformed into charcoal1 which is a by-product of some value4 ,illustration3 ,,fig4 #hg4--,riche distilling-producer4 ,the lower part of this cast retort 7,fig4 #hg7 is lined with charcoal1 the residue of previous distillations4 ,the wood which is introduced in the upper part of the retort is distilled in the chamber4 ,the retort is held by its own weight in a socket on the foot1 which socket is lined with a special refractory cement1 made of silicate1 asbestos forming the joint4 ,the products of combustion1 issuing from the furnace1 pass by way of the flue to the lower part of the casing1 and raise the temperature of the retort and the charcoal it contains to that of a cherry red 7#a1feb degrees ,f474 ,these products of combustion then float to the upper part of the casing and heat the top of the retort to a temperature of about #geb degrees ,f41 in which part the wood or the wooden waste to be distilled is enclosed4 ,thence the products of combustion pass through a horizontal flue1 provided with a damper1 into a collecting flue by which they are led to the smoke-stack4 ,the products of distillation formed in the chamber1 having no outlet at the top of the retort1 must traverse the zone filled with incandescent carbon4 ,the condensible products are conducted as permanent gases 7carbonic-acid gas in the state of carbon monoxide7 and are collected in the receptacle1 after having passed the funnel and the bell of the purifying apparatus4 ,a gas-furnace is formed by grouping in a single mass of masonry a certain number of elements of the kind just described4 ,it is essential that the retorts should be vertically placed1 that they be made only of cast metal and not of refractory clay1 and1 finally1 that their diameter be not much more than #aj inches1 which size has been found most expedient in practice4 ,the gas collected in the bell or in one or more of the receptacles passes into the gasometer and then into the service pipes4 ,if #b4b pounds of wood be distilled by burning in the furnace #h_/i of a pound of coal of average quality or #b4b pounds of wood 7either sawdust or waste71 #bd4e to #bh cubic feet of gas will be generated having a thermal value of #c1jjj to #c1cjj calories per cubic meter 7#aa1ijd to #ac1jid ,b4,t4,u4 per #ce4ca cubic feet71 and a residue #dd pounds of charcoal will be left4 ,in practice only the wood of commerce containing in the green state #bj to #dj per cent4 of water1 depending upon the variety1 is used4 ,hornbeam contains the least water 7#ah per cent471 while elmwood and spruce contain the most 7#dd to #de per cent474 ,the blast apparatus of the generator being started1 the gas is supplied under pressure4 ,by reason of its permanent composition and its richness1 it is an excellent substitute for street-gas in incandescent lighting1 a good furnace fuel reducing agent4 ,producers ,using ,wood ,waste1 ,sawdust1 and the ,like4--,if waste wood in the form of shavings1 sawdust1 straw1 bark1 and the like1 should be employed1 a still higher efficiency is obtained with self-reducing generators of the ,riche type4 ,combustion-,generators4--,in combustion-generators 7,fig4 #hh7 the fuel is burnt and not distilled4 ,the generator comprises two distinct elements4 ,the first is the generator proper1 in which the combustion takes place4 ,upon it is placed a hopper or fuel supply box4 ,the ,second element is the reducer1 in which by an independent process the reduction of the carbonic-acid gas1 the dissociation of the steam1 and the transformation of the hydrocarbons takes place4 ,the generator is provided at its base with a grate having oblique bars in tiers1 which grate is furnished with a channel in which the water for the generation of hydrogen flows4 ,on a level with this grate1 at the opposite side1 is a flue communicating with the reduction column of coke4 ,the incandescent zone of the generator should not extend above the level of the grate4 ,instead of passing through the layers of fresh fuel and out by way of the top1 the gas generated flows directly into the reduction column where it heats the coke to incandescence4 ,the high temperature to which the coke is subjected1 coupled with the injection of air1 effects useful reactions4 ,this additional air1 however1 is not used if the fuel is free from all products of distillation4 ,illustration3 ,,fig4 #hh4--,riche combustion-producer4 ,experience has shown that gas of #a1jjj to #aajj calories per cubic meter 7#c1ifh to #d1cfe ,b4,t4,u4 per #ce4ca cubic feet71 which heat content is necessary to develop one horse-power per hour1 can be obtained with #c4if pounds of wood in the form of shavings and sawdust containing #cj per cent4 of water4 ,the corresponding quantity of coke consumed in the reduction column is insignificant1 and may be placed at about #j4aab pounds per horse-power per hour4 ,it has been proven in actual practice that1 both in the distilling and combustion types of apparatus1 the wood1 either in the green state or in the form of saw-mill waste1 may contain as much as #fj per cent4 of water4 ,either of the two systems can be operated under pressure with an air-blast1 in which case a gas-holder and bell must be employed4 ,the gas as it passes from the generator to the gas-holder is conducted through a cooler and washer and through a moss filter1 which removes traces of the products that may have escaped the distillation4 ,inverted ,combustion4--,with a few exceptions the pressure-generators which have been described1 as well as suction gas-producers which will be later discussed1 are fed with anthracite coal or with coke4 ,they cannot be operated with moderately soft or bituminous coal4 ,for this reason they limit the employment of producer-gas engines4 ,manufacturers have long sought generators in which any fuel whatever can be consumed4 ,among the producers which seem to overcome the objections cited to a certain degree1 are those which are based on the principle of inverted combustion4 ,these apparatus embody the ideas of ,ebelmen1 the products of distillation being decomposed by passing them over layers of incandescent fuel4 ,illustration3 ,,fig4 #hi4--;,deschamps inverted-combustion producer4 ,many writers place in the class of inverted combustion producers1 apparatus of the ,riche1 ,thwaite1 and ,duff type1 in which this idea is also carried out4 ,riche employs an independent incandescent mass to reduce the products of distillation of another mass4 ,thwaite employs two vessels which serve alternately as distilling retorts and reducing columns4 ,duff draws in the products of distillation for the purpose of blowing them under the fire4 ,all these generators can hardly be said to be of the inverted combustion type4 ,illustration3 ,,fig4 #ij4--;,fange-,chavanon inverted-combustion producer4 ,the generators of ,deschamps 7,fig4 #hi7 and of ,fange and ,chavanon 7,fig4 #ij71 on the other hand1 are producers in which the combustion is really inverted1 and which are worked continuously4 ,the air enters at the upper part of the retort1 passes through the entire mass of fuel1 carrying with it the distilled volatile products1 and when the mixture reaches the incandescent zone1 chemical reactions occur that result in the production of a gas entirely free from tar and other impurities4 ,,chapter ,,xiii ,,suction ,,gas-,,producers ,the high cost and the complicated nature of the pressure gas-generators which have just been discussed have led manufacturers to attempt in some other way the generation of producer-gas intended for operating motors4 ,several inventors1 among whom we will mention ,benier and ,a4 ,taylor 7in ,france71 made some praiseworthy although not immediately very successful attempts to simplify the manufacture of producer-gas4 ,advantages4--,in these systems the suction occasioned by the motor itself has taken the place of a forced draft1 produced in the generator by an air-injector or a fan1 so that the gas1 instead of being stored under pressure in a gas-holder1 is kept in the apparatus under a pressure below that of the atmosphere4 ,as the device for producing a draft by means of boiler pressure or of a fan1 and the gas-holder1 are dispensed with1 the result is a saving1 first in the cost of installation1 consumption1 and floor space4 ,furthermore1 the cooler and washer are supplanted by a single scrubber4 ,manufacturers have succeeded in devising apparatus remarkable for the simplicity of the processes employed and yielding economical results which would never be obtained with pressure-generators employing gas-holders and boilers1 considering that the boiler alone calls for a consumption of from #ae to #cj per cent4 of the total amount of coal used for making the gas4 ,the best results obtained by the author with pressure gas-producers have indicated a consumption of not much less than #a to #a-a_/d pounds of anthracite per horse-power per hour at the motor1 while with suction-generators1 under similar conditions and with the same grade of fuel1 he has repeatedly found a consumption of from #i_/aj pounds per effective horse-power per hour4 ,in either case1 the gas obtained developed between #a1ajj and #a1cjj calories 7#d1cfe and #e1aeh ,b4,t4,u4 per #ce4ca cubic feet7 if produced from anthracite yielding from #g1ejj to #h1jjj calories 7#bi1gfc to #ca1gdf ,b4,t4,u47 per #b4b pounds4 ,the suction apparatus will also work very well with inferior coal containing up to #f to #h per cent4 of volatile matter and from #h to #aj per cent4 of ash4 ,this great advantage added to all the others explains the favorable reception which ,european manufacturers at once gave to suction-producers4 ,the petroleum engine itself will find a serious competitor in the new system4 ,as regards the possibility of employing suction gas generators with respect to the somewhat peculiar properties of the fuel1 it may be said at the outset that coke from gas works yielding from #f1jjj to #f1ejj calories 7#bb1iaa to #bd1iie ,b4,t4,u47 and also charcoal are perfectly available4 ,one horse-power per hour is obtained with a consumption of #a4a to #a4c pounds of coke4 ,blast-furnace coke may be used in case of need1 but its employment is not to be recommended on account of the sulphides it contains1 which sulphides1 being carried along by the gas1 are liable to form sulphuric acid with the steam1 the corrosive action of which would soon destroy the cylinder and other important parts of the engine4 ,qualities of ,fuel4--,anthracite coal is1 upon the whole1 so far the best available fuel for generators4 ,however1 it should possess certain qualities which will now be briefly indicated4 ,in suction gas-generators1 above all1 it is important that no harmful resistance should be opposed to the passage of the air and of the gas produced4 ,it is therefore necessary to employ coal of a size that will answer the foregoing condition1 without being too expensive4 ,the size of the pieces1 to a certain extent1 determines the price2 and with coal of the same properties1 pieces #a4a to #b inches may cost #a4d of the price for the ordinary size of #j4ei to #j4ih inches1 which is very well adapted for gas-generators4 ,this is the size of a hazel-nut4 ,moreover1 it will be advisable to select the dryest coals1 containing a minimum of volatile matter and having no tendency to coke or to cohere1 in order that the volatilized products may not by distillation obstruct the interstices through which the gases must pass4 ,for the same reason coal which breaks up and becomes pulverized under the action of the fire is not to be recommended4 ,the coal should also be such as to avoid the formation of arches which would interfere with the proper settling of the fuel during its combustion4 ,it may be stated as a rule that1 with coal that does not cohere1 the content of volatile matter should not exceed #e to #h per cent4 ,coal which contains more than #aj to #ae per cent4 of ash should not be used1 for the reason that it chokes up and obstructs generators in which the dropping and discharge of the ashes is done automatically1 a fact which should not pass unnoticed4 ,the furnace cannot be cleaned safely with a fire of this kind1 where combustion takes place in an enclosed space1 without hindering the production of gas4 ,here again a point may be raised very much in favor of suction gas-producers4 ,in a good generator1 the ash-pit can be cleaned and the fire stoked without interrupting the liberation of the gas drawn in and without appreciably impairing the quality of the gas4 ,these considerations are of importance so far as the gas-generator itself is concerned4 ,other conditions which should be noticed affect the engine fed by the generator1 the grade of coal used1 and the purification of the gas obtained from it4 ,unless special chemical cleaners and purifiers are employed1 thereby complicating the plant1 the coal utilized should yield as little tar as possible during distillation2 for the tendency of the tar to choke up the pipes and to clog the valves is one of the chief causes of defective operation of producer-gas engines4 ,tar changes the proper composition of the explosive mixture4 ,when it catches fire in the cylinder it causes premature ignition1 which is so dangerous in large engines4 ,from what has been said in the foregoing1 it follows that1 in the present state of the art1 the satisfactory operation of gas-generators depends no longer on the use of pure anthracite1 such as ,pennsylvania coal in ,america and ,welsh coal in ,england1 containing an amount of carbon as high as #ij to #id per cent4 and having a thermal value of #cc1ebi ,b4,t4,u4 ,on the contrary1 good dry coal yielding from #bi1gfc to #ca1gdf ,b4,t4,u4 is quite suitable for the generation of producer-gas4 ,a final1 practical advantage which speaks in favor of a generator and motor plant as compared with a steam-engine1 is the small amount of water required4 ,apart from the water used for cooling the engine1 which may be used over and over again if cooled1 any water1 whether it forms scale or deposits1 may be employed for cooling and washing the gas in the scrubber4 ,according to the author's personal experience1 an average of #c4c gallons of water per effective horse-power per hour is sufficient for this purpose4 ,this is about one-half of the amount required by a non-condensing slide-valve engine of from #ae to #cj horse-power4 ,the difference in the consumption of water is quite important in city plants1 where water is rather expensive as a rule4 ,general ,arrangement4--,a suction gas-generator plant of the character we have been discussing is shown in ,fig4 #ia4 ,illustration3 ,,fig4 #ia4--;,engine and suction gas-producer4 ,the apparatus ,a is the generator proper1 in which combustion takes place4 ,the gas produced passes into the apparatus ,b through a series of tubes1 to be conveyed to the washer ,c4 ,in the apparatus ,b1 which is the vaporizer1 the water admitted at the top under atmospheric pressure is vaporized by contact with a series of tubes1 heated by the gas coming from the generator4 ,the steam1 together with air1 is drawn into the lower part of the generator to support combustion4 ,this vaporizer is provided with an overflow for the outlet of the water which has not been vaporized4 ,the producer-gas pipe which leads from the vaporizer to the washer has a branch ,d1 for the temporary escape to the atmosphere of the gas produced before and after the operation of the engine4 ,in the washer1 as the drawing shows1 the gas enters at the bottom and leaves at the top to pass to the gas expansion-chamber ,e and thence to the motor4 ,the gas thus passes through the body of coke in the opposite direction to the wash water1 which then flows to the waste-pipe4 ,the coke and the water free the gas not only from the dust carried along1 but from the ammonia and other impurities contained in the gas4 ,when firing the generator1 a small hand ventilator ,g is used for blowing in air to fan the fire4 ,the gas obtained at first1 being unsuitable for combustion1 is allowed to escape through the branch ,d4 ,after injecting air for about #aj to #ae minutes1 the engine can be started after closing the branch ,d4 ,the suction of the engine itself will then gradually bring about the proper conditions for its regular running1 and after a quarter of an hour or half an hour the gas is rich enough to run the engine under a full load4 ,the apparatus just described is the original type1 upon which many improvements have been made for the purpose of securing a uniform gas production and of diminishing the interval of time elapsing between the firing of the generator and the running of the engine under a full load4 ,each of the elements of this apparatus--to wit1 the generator1 vaporizer1 super-heater1 and washer--have been modified and improved more or less successfully by the manufacturers2 and in order that the reader may perceive the merits and the drawbacks of the various arrangements adopted1 the most important ones will be separately discussed4 ,generator4--,with respect to the general arrangement of parts1 generators may be divided into two classes3 ,first4--,generators with internal vaporizers1 such as the ,otto ,deutz and ,wiedenfeld generators4 ,illustration3 ,,fig4 #ib4--,old type of ,winterthur producer4 ,second4--,generators with external vaporizers1 such as the ,taylor1 ,bollinckx1 ,pintsch1 ,kinderlen1 ,benz1 ,wiedenfeld1 ,hille1 and ,goebels generators4 ,cylindrical ,body4--,the generator consists essentially of a mantle made of sheet-iron or cast-iron and containing a refractory lining which forms a retort1 a grate1 and an ash-pit4 ,in the small size apparatus the cast-iron mantle is often used1 whereas in large sizes the mantle is made of riveted sheet-iron so as to reduce its weight and its cost4 ,in the latter case the linings are securely riveted or bolted4 ,the ,winterthur generator 7,figs4 #ib and #ic71 the ,taylor generator 7,fig4 #id71 and the ,benz generator 7,fig4 #ig71 are made of cast-iron2 the ,wiedenfeld generator 7,fig4 #ie71 the ,pintsch generator 7,fig4 #if71 are made of sheet-iron2 the ,bollinckx 7,fig4 #ih7 is made partly of sheet-iron and partly of cast-iron4 ,the different parts of a generator1 if made of sheet-iron1 are held together by means of angle-irons forming yokes1 and a sheet of asbestos is interposed4 ,if the parts are made of cast-iron1 they are connected after the manner of pipe-joints and packed with compressed asbestos4 ,this latter way of assembling the parts presents the advantage of allowing them to be dismembered readily4 ,therefore1 it allows the several parts to expand freely and facilitates the securing of tight joints4 ,this last consideration is exceedingly important1 particularly for the joints which are beyond the zone in which the distillation of the fuel takes place4 ,any entrance of air through these joints would necessarily impair the quality of the gas1 either by mingling therewith1 or by combustion4 ,the air so admitted would also be liable to form an explosive mixture which might become ignited in case of a premature ignition of the cylinder charge during suction or through some other cause4 ,illustration3 ,,fig4 #ic4--,new type of ,winterthur producer4 ,illustration3 ,,fig4 #id4--,the ,a4 ,taylor producer4 ,illustration3 ,,fig4 #ie4--,wiedenfeld producer4 ,illustration3 ,,fig4 #if4--,pintsch producer4 ,illustration3 ,,fig4 #ig4--;,benz producer4 ,illustration3 ,,fig4 #ih4--;,bollinckx producer4 ,illustration3 ,,fig4 #ii4--,lencauchez producer4 ,refractory ,lining4--,the interior lining of the generator should be made of refractory clay of the best quality4 ,it would seem advisable1 in order to facilitate repairs1 to employ retorts made of pieces held together instead of retorts made of a single piece4 ,in the first case the assembling should preferably be made by means of refractory cement1 and the inner surface should be covered with a coating so as to form a practically continuous stone surface4 ,illustration3 ,,fig4 #ajj4--;,goebels producer4 ,some manufacturers1 in order to allow for the renewal of the part most liable to be burnt1 employ at the bottom of the tank a refractory moulded ring 7,lencauchez1 ,fig4 #ii74 ,it is always advisable to place between the shell or mantle of the generator and the refractory lining a layer of a material which is a bad conductor of heat as1 for instance1 asbestos or sand1 in order to avoid as much as possible loss of heat due to external radiation 7,fig4 #ajj74 ,illustration3 ,,fig4 #aja4--,pierson producer4 ,grate and ,support for the ,lining4--,these parts1 owing to their contact with the ashes and the hot embers1 are liable to deteriorate rapidly4 ,it is therefore indispensable that they should be removable and easily accessible1 so that they may be renewed in case of need4 ,from this point of view1 grates composed of independent bars would appear to be preferable4 ,the clearance between the bars depends1 of course1 on the kind of ashes resulting from the different grades of fuel4 ,it is advisable to design the grate so that the free passage for the air is about #fj to #gj per cent4 of the total surface4 ,in generators having a cup-shaped ash-pit1 containing water 7,fig4 #ie71 the grate and the base of the retort are less liable to burn than in apparatus having dry ash-pits4 ,certain apparatus1 such as those of ,lencauchez 7,fig4 #ii71 ,pierson 7,fig4 #aja71 and ,taylor 7,fig4 #id71 have no grates2 the fuel is held in the retort by the ashes1 which form a cone resting on a sheet-iron base1 easy of access for cleaning and from which the fuel slides down gradually4 ,the ,pierson generator 7,fig4 #aja7 is provided with a poker comprising a central fork1 which is worked with a lever1 in order to stir the fire from below without entirely extinguishing the cone of ashes4 ,in some apparatus in which a grate is used 7,fig4 #ib71 a space is left between the grate and the support of the retort4 ,this arrangement has the merit of allowing only finely divided and completely burnt ashes to pass to the ash-pit4 ,moreover1 a large surface grate can be employed1 thus facilitating the passage of the mixture of air and steam4 ,illustration3 ,,fig4 #ajb4--,kiderlen producer4 ,the space above mentioned is provided with a cleaning-door through which cinder and slag may be removed4 ,in other apparatus the grate rests either on the support of the refractory lining1 as in the old type invented by ,wiedenfeld 7,fig4 #ie71 or upon a projection embedded in the lining1 as1 for instance1 in the ,kiderlen 7,fig4 #ajb7 and ,pintsch generators 7,fig4 #if74 ,in the ,riche apparatus 7,fig4 #ajc7 there is1 besides the ordinary grate1 a grate with tiers on which the fuel spreads4 ,this grate consists of wide1 hollow bars containing water4 ,it should be noted that the apparatus is of the blower type4 ,illustration3 ,,fig4 #ajc4--,riche combustion-producer4 ,an interesting arrangement is found in ,benier's generator 7,fig4 #ajd74 ,this consists of a grate formed of projections cast around a cylinder which can be turned about its axis4 ,the finely divided ashes which are retained in the spaces between these projections are thus carried into the ash-pit1 and those which adhere to the metal are scraped away by a metallic comb fastened to the lower part of the apparatus4 ,the ,phoenix generator 7,fig4 #aje7 is fitted with a grate having a mechanical cleaning device1 worked by a lever from the outside4 ,illustration3 ,,fig4 #ajd4--;,benier producer4 ,illustration3 ,,fig4 #aje4--,phoenix producer4 ,ash-,pit4--,the ash-pits are exposed to the destructive effects of heat and moisture1 and should preferably be constructed of cast-iron1 since sheet-steel is liable to corrode quickly4 ,illustration3 ,,fig4 #ajf4--,otto ,deutz producer4 ,in most apparatus the ash-pit is hermetically sealed1 and the air for supporting combustion enters below the grate through a pipe leading from the heater or the vaporizer4 ,this arrangement seems best adapted to prevent the leakage of gas which tends to take place by reaction after each suction stroke of the engine4 ,ash-pits formed as water-cups1 such as the ,deutz 7,fig4 #ajf71 the ,wiedenfeld 7,fig4 #ie71 and the ,bollinckx 7,fig4 #ih71 are fed by the overflow from the vaporizer4 ,these ash-pits are themselves provided with an overflow consisting of a siphon-tube forming a water-seal4 ,besides providing protection to the grate and other parts by this sheet of water1 a larger proportion of the heat radiated from the furnace is utilized for the production of steam which contributes to enrich the gas4 ,the doors of the ash-pits and their fittings are likewise exposed to a rapid deterioration4 ,for this reason these parts should be very strongly made1 either of cast-iron or cast-steel4 ,furthermore1 they should1 at joint surfaces1 be connected in an air-tight manner1 which may be attained by carefully finishing the engaging surfaces of the frame and the door proper1 or by cutting a dovetail groove in one of the sides of the frame which is packed with asbestos and adapted to receive a sharp edged rib on the other part4 ,the pintles of the hinges should also be carefully adjusted so that the joint members of the door shall remain true4 ,hinges with horizontal axes seem to be preferable in this respect to those having vertical axes4 ,as a means of closing the door1 the arrangement here shown 7,fig4 #ajg7 seems to assure a proper engagement of the joint surfaces4 ,it consists of a yoke which straddles the door1 and which1 on the one hand1 swings about the hinge1 and on the other hand engages a movable hoop4 ,a screw1 fastened to the yoke1 serves to tighten the door by pressure on its center4 ,this screw can also be fastened to the end of the yoke 7,fig4 #ajh74 ,illustration3 ,,figs4 #ajg-ajh4--;,fire-box doors4 ,it is very advantageous to provide in each door a hole closed by an air-tight plug1 so that in case of need a tool may be introduced for cleaning the grate4 ,in this manner the grate may be cleaned without opening doors and without causing a harmful entrance of air4 ,the door of the furnace1 particularly1 should be provided with an iron counter-plate held by hinged bolts 7,fig4 #aji72 or1 better still1 this door should be so constructed that it can be lined with refractory material to protect it against the radiated heat of the fire4 ,charging-,box4--,like the other parts of the generator the construction of which has been discussed above1 the charging-box should be absolutely air-tight4 ,on account of their greater security1 preference should be given to double closure devices1 which form a sort of preliminary chamber1 owing to which the filling of the generator is made in two operations4 ,the first operation consists in filling the preliminary chamber after opening the outer door4 ,upon closing this outer door1 the second operation is performed1 which consists in moving the inner door so as to cause the fuel in the preliminary chamber to drop into the generator4 ,stress has been laid on the greater safety of this type of charging-box for the reason that1 with devices having a single charging-door1 a sudden gust of air may rush in at the time of charging the furnace1 and bring about an explosion very dangerous to the workman entrusted with stoking the furnace4 ,illustration3 ,,fig4 #aji4--;,door with refractory lining4 ,the closure is generally simply a removable cover1 or may be a lid swinging about a hinge having a horizontal or vertical axis4 ,as regards the inner door1 which is of great importance1 in order to insure an air-tight joint1 there are three chief types of closure3 #a4 ,the ,lift-,valve4 #b4 ,the ,slide-,valve4 #c4 ,the ,cock4 ,the ,lift-,valve4--,the lift-valve is formed by a disk of conical or spherical shape moved up and down by means of a lever having a counter-weight for adjustment4 ,the valve is used in the ,winterthur 7,fig4 #ib7 and ,bollinckx 7,fig4 #ih7 generators4 ,this device serves as an automatic closure and insures a tight joint irrespective of wear4 ,moreover1 it presents the advantage that1 at the moment of opening1 it distributes the fuel evenly in the generator2 but on the other hand1 it has the drawback of not allowing the fuel to be examined or shaken through the charging-box4 ,in apparatus provided with this kind of valve1 it is therefore advisable to furnish the upper part of the generator with agitating holes closed by an air-tight slide4 ,slide-,valve4--,the slide-valve closure consists of a smooth-finished metallic plate movable below the charging-box proper4 ,operated as it is from the outside1 it is evident that the slightest play1 the wearing of the pivot1 or the weight of the charge1 will form spaces between the plate and its seat through which air may rush in4 ,furthermore1 the manipulation of the slide-valve may be interfered with if too much fuel is put in the generator4 ,the valve or damper may move parallel to itself or swing about the operating axis4 ,the ,taylor apparatus 7,fig4 #id7 and the ,benier apparatus 7,fig4 #ajd7 are provided with such valves4 ,the ,pintsch generator 7,fig4 #if7 is provided with a device which1 properly speaking1 is not a damper1 but which consists of two boxes movable about a vertical axis and arranged to be displaced alternately above the shaft to effect the charging4 ,this system effects only a single closure1 but explosions are scarcely to be feared with an apparatus of this kind1 owing to the considerable height of fuel contained between the charging opening and the gas-producing zone4 ,cock4--,the cock is applied particularly in the modern apparatus of the ,otto ,deutz ,co4 7,fig4 #ajf7 and the ,pierson generator 7,fig4 #aja74 ,it consists of a large cast-iron cone1 having an operating handle and an opening4 ,the cone moves in a sleeve formed by the charging-box4 ,this arrangement appears to be preferable to the others on account of its simplicity and of the ease with which it can be taken apart for cleaning4 ,moreover1 the fuel can be poked directly through the feed-hopper4 ,in apparatus provided with a cock1 it is advisable to place on the outside cover a mica pane through which the condition of the fuel may be examined without danger4 ,feed-,hopper4--,below the charging-box is arranged1 as a rule1 a hopper tapered conically downward4 ,this part of the generator should serve only as a storage chamber for fuel4 ,it can therefore be made of cast-iron1 and has the advantage of being removable1 easily replaced1 and of allowing ready access to the retort for the purposes of examination and repair4 ,the annular space surrounding this feed-hopper generally forms a chamber for receiving the gas produced1 as in the ,winterthur 7,fig4 #ib71 the ,bollinckx 7,fig4 #ih71 and the ,taylor apparatus 7,fig4 #ii74 ,in generators having an internal vaporizing-tank1 this tank itself serves as a feed-hopper1 which is the case in the ,deutz apparatus 7,fig4 #ajf7 and ,wiedenfeld generator 7,fig4 #ie74 ,connection of ,parts4--,in order to facilitate the thorough cleaning of the retort1 preference is given to removable charging-boxes and feed-hoppers4 ,these are features of apparatus of the ,bollinckx type 7,fig4 #ih71 in which the charging-box is secured to the generator by means of its yoke and by catches provided with knobs1 and also of apparatus of the ,winterthur kind 7,fig4 #ib71 having a charging-box pivoted about a vertical axis1 or apparatus of the ,duplex type 7,fig4 #aaj71 in which the charging-box can swing about a horizontal hinge4 ,air ,supply4--,we have seen that1 when starting the generator1 the gas is produced with the aid of a fan4 ,this fan may be operated mechanically1 but is generally operated by hand4 ,it is customary to convey the air-blast through a pipe leading to the ash-pit1 as in the ,winterthur apparatus 7,fig4 #ib74 ,often1 however1 the air supply pipe is directly branched on that which leads from the vaporizer to the ash-pit1 as in the ,deutz apparatus 7,fig4 #ajf74 ,in this case a set of valves or dampers permits the disconnection of the fan or its connection with the ash-pit4 ,illustration3 ,,fig4 #aaj4--;,duplex charging-hopper4 ,in some apparatus an air inlet is provided immediately adjacent to the ash-pit4 ,this arrangement is faulty for the reason that it gives rise to gaseous emanations which take place by reaction after each suction stroke of the engine4 ,furthermore1 it is advisable that the air supplied below the ash-pit be as hot as possible4 ,for this reason the employment of preheaters is desirable4 ,the dry air forced in by the fan stimulates combustion1 and the hot gas produced and mixed with smoke escapes through a separate flue1 generally arranged beyond the vaporizer and serving as a chimney4 ,this chimney should in all cases be extended to the outside of the building1 and should never terminate in a brick chimney or similar smoke-flue4 ,the direct escape of such gas and smoke through a telescopic chimney above the charging-box has been generally abandoned in modern structures4 ,illustration3 ,,fig4 #aaa4--;,bollinckx flue and scrubber4 ,illustration3 ,,fig4 #aab4--,winterthur flue and air-reheater4 ,the escape-pipe mentioned1 being branched on the gas-pipe leading to the engine1 should be capable of disconnection when desired1 by a thoroughly tight system of closure4 ,for this purpose1 some employ a simple cock 7,bollinckx1 ,fig4 #aaa71 a three-way cock1 a set of cocks1 or1 still better1 a double valve1 as in the ,winterthur apparatus 7,fig4 #aab7 and the ,deutz apparatus 7,fig4 #aac74 ,a double seated valve is also used1 as is the case in the ,benz generator 7,fig4 #aad74 ,illustration3 ,,fig4 #aac4--,otto ,deutz flue4 ,illustration3 ,,fig4 #aad4--;,benz flue4 ,vaporizer-,preheaters4--,as has been stated before1 there are vaporizers internal or external1 relatively to the generator4 ,internal ,vaporizers4--,the ,deutz apparatus 7,fig4 #ajf71 for example1 consists of an annular cast-iron tank mounted above the retort of the generator4 ,the hot gases given off by the burning fuel travel around this tank and vaporize the water which it contains4 ,the air drawn in by the suction of the engine enters through an opening located above the tank1 travels over the surface of the water which is being vaporized1 and thus laden with steam passes to the ash-pit4 ,the tank in question is supplied with water by means of a cock having a sight feed1 located on the outside1 and the level is kept constant by means of an overflow tube leading to the ash-pit4 ,it is well to bend this tube and to place a funnel on its lower member4 ,the amount of overflow may thus be regulated4 ,these vaporizers are simple and take up little room2 but they are open to the apparently well-founded objection that they heat up slowly and require a considerable time to produce the steam necessary to enrich the gas1 this being due to the relatively large mass of cast-iron and the amount of water contained therein4 ,the ,pierson vaporizer 7,fig4 #aja7 and the ,chavanon vaporizer 7,fig4 #aae7 both consist of an annular tank forming the base of the generator4 ,steam is formed near the outlet of the ashes1 which1 as has been described above1 leads to the outer air4 ,the development of steam is regulated by mechanical means controlled by the suction of the engine4 ,illustration3 ,,fig4 #aae4--;,chavanon producer4 ,external ,vaporizers4--,external vaporizers are generally formed by a cylinder with partitions constituting two series of chambers4 ,in one of these the hot gases from the generator travel1 and in the others the water to be vaporized is contained4 ,illustration3 ,,fig4 #aaf4--,taylor vaporizer4 ,illustration3 ,,fig4 #aag4--;,deutz vaporizer4 ,tubular ,vaporizers4--,different types of tubular vaporizers are manufactured4 ,the vaporizer with a series of tubes1 as in ,taylor's apparatus 7,fig4 #aaf71 ,deutz's old model 7,fig4 #aag71 or with single tube like ,pintsch's generator 7,fig4 #aah71 is formed by three compartments separated by two tube sheets or by plates which are connected by tubes4 ,in some cases the gases pass within the tubes1 while the water to be vaporized surrounds them2 as in the ,pintsch apparatus 7,fig4 #aah71 and ,taylor apparatus 7,fig4 #aaf71 ,benz 7,fig4 #aai71 and ,koerting generators 7,fig4 #abj74 ,illustration3 ,,fig4 #aah4--,pintsch vaporizer and scrubber4 ,in other cases1 the water lies inside and the gas outside4 ,in this latter case1 a longitudinal baffle is employed to compel the gases to heat the tubes in their whole length1 as in the ,deutz producer 7,fig4 #aag74 ,in a general way it may be said that such a series of tubes presents the disadvantage of becoming clogged up rapidly by the deposit of lime salts contained in water4 ,illustration3 ,,fig4 #aai4--;,benz vaporizer4 ,illustration3 ,,fig4 #abj4--,koerting vaporizer4 ,if the set of tubes consists of fire-tubes1 the deposit will form on the outer surface1 that is1 on a portion not accessible for cleaning4 ,from this point of view1 water-tubes are preferable1 as they allow the deposit or scale to be removed through the tubular heads or plates4 ,on the other hand1 such water-tubes have the drawback that their exterior surfaces are readily covered with pitch and soot4 ,the tubular vaporizers of the ,field type 7,bollinckx1 ,fig4 #ih7 are composed of a single sheet-iron tube or shell1 in which the tubes are arranged1 dipping into a chamber through which the hot gases pass4 ,this arrangement insures a rapid production of steam1 but the ,field tubes are even more liable than the others to become covered with deposits4 ,it will be seen that these types of vaporizers should all present the following features3 easy access1 small quantity of the body of water undergoing vaporization1 and large heating surface with small volume4 ,the use of copper or brass tubes should be strictly avoided1 as they would be quickly corroded by the action of the ammonia and hydrogen sulphide contained in the gas4 ,partition ,vaporizers4--,partition vaporizers comprise a cylindrical shell1 generally made of cast-iron and having a double wall in which the water to be vaporized circulates4 ,the gas coming from the generator passes into the central portion1 where it comes in contact with a hollow baffle1 also containing water 7,wiedenfeld1 ,fig4 #aba74 ,vaporizers of this kind are strong1 simple1 and easily cleaned4 ,operation of the ,vaporizers4--,the general purpose of vaporizers1 whatever their construction may be1 is to produce steam under atmospheric pressure1 by utilizing the heat of the generator gases immediately after their production1 or1 as in the ,chavanon system1 by utilizing the heat radiated from the furnace4 ,the air drawn by the engine through the generator generally passes through the vaporizers and becomes laden with a certain amount of steam which it carries along4 ,the amount thus taken up depends chiefly upon the temperature and the amount of gases coming from the generator1 so that the greater the amount drawn into the engine1 the more energetic will the vaporization be1 and the richer the gas will become4 ,it will be understood that when a generator is working at its maximum production1 the interior temperature is highest and most favorable to the decomposition of the largest amount of steam4 ,illustration3 ,,fig4 #aba4--,wiedenfeld vaporizer4 ,it follows that with the very simple vaporizers which have been reviewed1 a practically automatic regulation is obtained4 ,however1 some manufacturers have deemed it advisable to regulate the amount of steam more accurately1 and to make it exactly proportionate to the power developed by the motor4 ,thus in the ,winterthur gas-producer 7,figs4 #ib and #aab7 the manufacturers have omitted the vaporizer proper1 and use instead an air-heater and a super-heater for air and steam4 ,the heater is formed by a cast-iron box having two compartments1 through one of which the hot gases from the generator pass1 while in the other the air intended to support combustion travels4 ,at the inlet of the super-heater a pipe terminates1 which feeds1 drop by drop1 water supplied by a feed device to be described presently4 ,this water is vaporized immediately upon contact with the wall of the super-heater and is carried along with the air contained in it4 ,the super-heater comprises a hollow ring-shaped cast-iron piece arranged in the chamber of the generator1 in which the gases are developed1 and is thus heated to a high temperature4 ,the mixture of air and steam circulates in this super-heater before traveling to the ash-pit4 ,the feeder of the ,winterthur gas-generator 7,fig4 #abb7 is composed of a receptacle having the shape of a tank or basin containing water and located below a closed cylindrical box4 ,in this box a piston moves1 which is provided at its lower end with a needle-valve4 ,the upper portion of the box communicates with the gas-suction pipe through a small tube4 ,at each suction stroke of the engine1 according to the force of the suction1 the needle-valve piston rises more or less and thus allows a variable amount of water to pass4 ,illustration3 ,,fig4 #abb4--,winterthur feeders4 ,this apparatus--and all those based on the same principle--presents the advantage of proportioning the amount of water to the work of the engine2 but in view of its rather sensitive operation it must be kept in perfect repair and carefully watched4 ,obviously1 should the water contain impurities1 the needle-valve will bind or the orifices will be obstructed1 and thus the feeding of the water will be interrupted4 ,this will not only result in the production of a poorer gas1 but will lead to greater wear of the grates1 which in this case are not sufficiently cooled by the introduction of steam4 ,illustration3 ,,fig4 #abc4--;,hille producer4 ,air-,heaters4--,the preliminary heating of the air appears to be of great utility for keeping up a good fire4 ,this heating is very easily accomplished1 and is generally effected by utilizing a portion of the waste heat of the gases1 a procedure which also has the advantage of cooling the gases before they pass through the washing apparatus4 ,the heating of the air for supporting combustion takes place either before the addition of steam 7,hille's generator1 ,fig4 #abc71 or after the mixture as in ,wiedenfeld's apparatus 7,fig4 #ie74 ,in the first case1 the air passes through a sheet-iron shell concentric with the basin of the generator1 is there heated by the radiated heat1 and is conveyed to the ash-pit by a tube into which leads the steam-supply pipe extended from the vaporizer4 ,in the second type of heater1 the mixture of air and steam is super-heated during its passage through an annular piece arranged in the ash-pit of the generator4 ,illustration3 ,,fig4 #abd4--;,benz dust-collector4 ,dust-,collectors4--,dust-collectors are generally placed between the generator and the scrubber or washer4 ,they may be formed of baffle-board arrangements against which the gases laden with dust impinge1 causing the dust to be thrown down into a box provided with a cleaning opening 7,benz1 ,fig4 #abd1 and ,pintsch1 ,fig4 #aah74 ,some collectors are formed either by the vaporizer itself1 terminating at its base in a tube which dips into water and forms a water-seal1 as in the ,wiedenfeld generator 7,fig4 #aba71 or by a water-chamber into which the gas-supply tube slightly dips 7,bollinckx1 ,fig4 #aaa74 ,with this arrangement1 the gas will bubble through the water and will be partly freed of the dust suspended in it4 ,these water-chambers are generally fed by the overflow from the spray of the scrubber4 ,there is thus produced a continuous circulation by which the dust1 in the form of slime1 is carried toward the waste-pipe or sewer4 ,cooler1 ,washer1 ,scrubber4--,some manufacturers cool the gas in a tower with water circulation4 ,most manufacturers1 however1 simply cool the gas in the washer or scrubber4 ,this apparatus comprises a cylindrical body of sheet-iron or cast-iron formed of two compartments separated by a wooden or iron grate or perforated partition4 ,the upper compartment up to a certain level contains either coke1 glass balls1 stones1 pieces of wood1 and the like4 ,the top of the compartment is provided with a water supply in the nature of a sprinkler or spray nozzle4 ,the lower compartment of the scrubber serves to collect the wash-water which has passed through the substance filling the tower4 ,an overflow in the shape of a siphon1 provided with a water seal1 carries the water to the waste-pipe either directly or after it has first passed through the dust collector4 ,the gas drawn in enters the washer in the lower compartment either above the water level 7,deutz1 ,fig4 #abe2 ,winterthur1 ,fig4 #abf71 or through an elbow which dips slightly into the water 7,benz1 ,fig4 #abg2 ,fichet and ,heurtey producer1 ,fig4 #abh74 ,the gas passes through the grate or partition which supports the material filling the tower1 and travels through the interstices in a direction opposite to that of the water falling from the top4 ,under these conditions1 the gas is cooled1 gives up the ammonia and the dust which it may still contain in suspension1 and is conveyed to the engine either directly or after passing through certain purifiers4 ,care should be taken to place the pieces of most regular shape along the walls1 so that the unevenness of their surfaces may not form upward channels along the shell1 through which channels the gas could pass without meeting the wash-water4 ,illustration3 ,,fig4 #abe4--,otto ,deutz scrubber4 ,illustration3 ,,fig4 #abf4--,winterthur scrubber4 ,illustration3 ,,fig4 #abg4--;,benz scrubber4 ,the material most commonly employed in washers is coke in pieces of from #b-a_/b to #c-a_/b inches in size4 ,this material is cheap and is very well suited for retaining the impurities of the gas4 ,the largest pieces of coke should be placed at the bottom of the washer1 and smaller pieces should form at the top a layer from #f to #h inches deep4 ,in this manner the water is distributed more evenly and the gas is more thoroughly washed4 ,blast-furnace coke is best suited for this washing1 as it is more porous and less brittle than gas-works coke4 ,it is advisable to put a baffle-board in front of the gas outlet to reduce the carrying along of water in the conduits4 ,illustration3 ,,fig4 #abh4--;,fichet-,heurtey scrubber4 ,illustration3 ,,fig4 #abi4--,scrubber-doors4 ,the tower of the washer should be provided with three openings having air-tight closures1 easily fastened by screws 7,fig4 #abi74 ,one of the openings is located in the lower compartment1 slightly above the water level1 to allow the deposits to be removed and to permit the cleaning of the orifice of the gas-supply tube1 which is particularly liable to be obstructed4 ,the second opening is placed above the grating which supports the filtering material4 ,the third opening is provided on the top of the apparatus to permit the examination and cleaning of the water feed device and the gas outlet without the necessity of taking the lid of the washer apart1 the joint of which is kept tight with difficulty4 ,the two openings last mentioned also serve for introducing and removing the filtering material4 ,purifying ,apparatus4--,in some cases1 where it is necessary to have very clean gas or where coal is employed which is softer than anthracite coal1 and which therefore produces an appreciable amount of tar1 supplementary purifying means must be employed4 ,the apparatus for this purpose may1 like the washers1 be based upon a physical action or upon a chemical action4 ,the physical action has for its purpose chiefly to retain the pitch and the dust which may have passed through the washer4 ,this is accomplished by means of sawdust or wood shavings arranged in a thin layer and capable of filtering the gas without opposing too great a resistance to its passage4 ,these materials are spread on one or more shelves superposed to form successive compartments in a box closed in an air-tight manner by an ordinary lid or a water seal cover 7,pintsch1 ,fig4 #acj2 ,fichet and ,heurtey1 ,fig4 #aca74 ,it may be well to point out that the presence of the water carried along will1 in the end1 destroy the efficiency of the precipitated materials1 because they swell up and cease to be permeable to the gas4 ,these materials must therefore be renewed rather frequently4 ,to obviate this drawback1 vegetable moss may be employed1 which is much less affected by moisture than most filters and keeps its spongy condition for a long time4 ,illustration3 ,,fig4 #acj4--,pintsch purifier4 ,the chemical action has for its chief object to rid the gas of the carbonic acid and the hydrogen sulphide which certain fuels give off in appreciable amounts4 ,the purifying material1 in this case1 is formed either by a mixture of hydrate of lime and natural iron oxide1 or by the so-called ,laming mass1 which consists of iron sulphide1 slaked lime1 and sawdust1 which last serves the purpose of rendering the material looser and more permeable to the gas4 ,the ,laming mass as well as other purifying materials will become exhausted in the course of chemical reactions4 ,it can be regenerated merely by exposure to the air4 ,illustration3 ,,fig4 #aca4--;,fichet-,heurtey purifier4 ,gas-,holders4--,the purifiers by themselves constitute1 to a certain extent1 storage chambers for the gas before it is supplied to the engine2 but in plants for the generation of gas without purifiers it is advisable to provide a gas-holder on the suction conduit near the engine4 ,illustration3 ,,fig4 #acb4--,pintsch regulating-bell4 ,in order to save floor space the gas-holder may be placed in the basement4 ,preferably the capacity of the holder should be at least from #c to #d times the volume of the engine-cylinder4 ,the holder should also be provided with a drain-cock and with a hand-hole located at some accessible point1 so that the slimes and pitch which tend to accumulate in the holder can be removed4 ,in some cases the gas-holder is formed by a small regulating bell1 the function of which is to insure a uniform pressure4 ,this bell is emptied during the suction period and is filled during the three succeeding periods of compression1 explosion1 and exhaust 7,pintsch1 ,fig4 #acb74 ,illustration3 ,,fig4 #acc4--,types of gas-driers4 ,drier4--,sometimes1 toward the end of a producer-gas pipe1 a drier is located for the purpose of keeping back the water carried along1 the drier being similar to that employed in steam conduits4 ,it will1 of course1 be understood that such driers are useful only in plants having no purifiers 7,fig4 #acc74 ,the employment of the drier is advisable to prevent the entrance of moist gas into the cylinder and the condensation of moisture on the electric igniter4 ,illustration3 ,,fig4 #acd4--;,elbow with closure4 ,pipes4--,the pipes connecting the several parts of a gas-producing plant should be disposed with particular care to insure tightness and cleanliness4 ,it should be borne in mind that the gas is under a pressure below that of the atmosphere1 and that the least leakage will cause the entrance of air1 which will impair the quality of the gas4 ,the greatest care should therefore be taken in fitting the joints4 ,these joints are numerous1 because there are joints wherever tubes are connected with each other and with the apparatus4 ,furthermore1 all elbows should be provided with covers held in place by a yoke and compression screw1 this being done for the purpose of providing for the introduction of a brush or other implement to remove the dust and pitch 7,fig4 #acd74 ,for conduits of small diameter the elbows with covers may be replaced with ,t connections1 or connections provided with plugs4 ,gas piping in the immediate neighborhood of the cock for admitting gas to the motor should be provided with a conduit of proper diameter leading to the open air and serving to clean the apparatus and to fill them1 during the operation of the fan1 with gas suitable for combustion4 ,this conduit should be provided with a stop-cock4 ,test-cocks for the gas should be placed on the piping immediately beyond the vaporizers1 the scrubber1 and near the engine4 ,it will also be well to provide water-pressure gages before and after the scrubber to enable the attendant to ascertain the vacuum in the conduits and to adjust the running of the apparatus4 ,purifying-,brush4--,as an additional precaution against the carrying of tar to the engine1 metallic brushes are often employed1 these brushes being spiral in form and enclosed in a cast-iron box interposed in the gas-supply pipe immediately after the engine4 ,the gas will be broken up into streams by the obstacles formed by these brushes and will be freed of the suspended tar 7,fig4 #ace74 ,these brushes should be carefully cleaned at regular intervals4 ,the best way of doing this is to drop them into kerosene or some other suitable solvent4 ,illustration3 ,,fig4 #ace4--,metal purifying-brush4 ,,conditions ,,of ,,perfect ,,operation ,,of ,,gas-,,producers ,these conditions depend upon the workmanship or upon the system of the plant1 on the care with which it has been erected1 on the nature of the fuel1 on the condition of preservation of the apparatus1 and upon the manner in which the producers have been working4 ,workmanship and ,system4--,the workmanship itself1 which term is meant to include the choice of materials and the way they have been worked1 presents no difficulty4 ,the producers which we have discussed are very simple and offer absolutely no difficulties in their mechanical execution4 ,as regards the system1 however1 especially with respect to the relative dimensions of the elements1 it does not seem so far that it is possible to indicate any principle or rule capable of a rigid general application4 ,it must be taken into account that the use of suction gas-generators has become general only in the last three or four years2 the problem has therefore scarcely been adequately solved4 ,however1 some hints may be given on this subject4 ,generator4--,in regard to the generator1 it is possible to deduce from the best existing plants the dimensions to be given to the generator relatively to those of the engine to be supplied1 upon the assumption that the engine is single-acting and runs at a normal speed of from #afj to #bcj revolutions per minute4 ,the essential portion of the generator which contributes to the production of a proper gas is that which corresponds with the combustion zone4 ,to this portion a cross-section is given varying in size between one-half and one-quarter of the surface of the engine-piston1 sometimes between one-half and nine-tenths of this surface1 according to the nature and the size of the fuel that is used4 ,with small apparatus1 however1 ranging from #e to #ae horse-power1 the size of the base cannot be reduced below a certain limit1 since otherwise the sinking of the fuel will be prevented4 ,this danger always exists in small generators and renders their operation rather uncertain1 such uncertainty being also due to the influence of the walls4 ,it is to be noted that most modern generators are rather too large than otherwise4 ,many manufacturers of no wide experience have been led to make their apparatus rather large so as to insure a more plentiful production of gas4 ,as a matter of fact1 the fire in such apparatus is liable to be extinguished when the combustion is not very active4 ,if the principles of the formation of gas in suction-generators be kept in mind1 it is evident that the gas developed is the richer the hotter the operation of the apparatus4 ,such operation also permits the decomposition of the hydrogen and carbon monoxide4 ,the hot operation of a generator is accomplished best with active combustion2 and since this is a function of the rapidity with which the air is fed1 it obviously is advantageous to reduce the area of the air-passage to a minimum as far as allowed by the amount of fuel to be treated4 ,as to the height of the fuel in use in the apparatus1 this varies as a rule between #d and #e times the diameter at the base4 ,vaporizer4--,the size of the vaporizer varies materially according to its type4 ,no hard-and-fast rule can therefore be adopted for determining its heating surface2 but this surface should in all cases be sufficient to vaporize under atmospheric pressure from 4#ff to 4#hc pounds of water per pound of anthracite coal consumed in the generator4 ,scrubber4--,for the scrubbers1 the following dimensions may be deduced from constructions now used by standard manufacturers4 ,the volume of a scrubber is generally from six to eight times the anthracite capacity of the generator4 ,a height of from three to four times the diameter is considered sufficient in most cases4 ,it should be understood that in this height is included the water-pan chamber located below the partition or grate1 and the upper chamber through which the gas escapes4 ,the height of these two chambers depends necessarily upon the arrangement used for leading the gas to the lower portion of the washer and for the distribution of wash-water at the top4 ,assembling the ,plant4--,the author has insisted strongly on the necessity of having all the apparatus and pipe connections perfectly tight4 ,in order to ascertain if there is any leakage1 the following procedure may be adopted3 ,when starting the fire by means of wood1 straw1 or other fuel producing smoke1 instead of allowing this smoke to escape through the flue during the operation of the fan1 it may be caused to escape through the cock which generally admits the gas to the motor1 the cock being opened for this purpose4 ,the damper in the outlet flue is closed4 ,in this manner the smoke will fill all the apparatus and connecting pipes under a certain pressure and will escape through any cracks1 the presence of which will thus be revealed4 ,another test1 which is made during the ordinary operation of the generator1 consists in passing a lighted candle along the joints2 if there is any leakage1 this will be shown by a deviation of the flame from a vertical position4 ,fuel4--,we have discussed the subject of fuel in a preceding chapter 7,chapter ,,xiii7 and have indicated the conditions to be fulfilled by low grade or anthracite coal best adapted for use in suction gas-generators4 ,it may here be added that the coal used in the generator should be as dry as possible and in pieces of from #a_/b inch to #a inch4 ,very small pieces1 and particularly coal dust1 are injurious and should be removed by preliminary screening as far as possible4 ,screened coal is thrown in with an ordinary grate shovel4 ,how to ,keep the ,plant in ,good ,condition4--,in regard to the generator1 apart from the cleaning of the grate and of the ash-pit1 which may be done during operation1 it is necessary to empty the apparatus entirely once a week1 if possible1 in order to break off the clinkers adhering to the retort4 ,these clinkers destroy the refractory lining1 form rough projections interfering with the downward movement of the fuel1 bring about the formation of arches1 and reduce the effective area of the retort4 ,at the time of this cleaning1 tests are also made as to the tightness of the doors of the combustion-chamber1 of the charging-boxes1 etc4 ,the vaporizer should be cleaned every week or every other week1 according to the more or less bituminous character of the fuel and the greater or smaller content of lime in the water used4 ,lime deposits may be eliminated1 or the salts may be precipitated in the form of non-adhering slimes1 by introducing regularly a small amount of caustic potash or soda into the feed-water4 ,if the deposits or incrustations are very tenacious1 the use of a dilute solution of hydrochloric acid may be resorted to4 ,tar which may adhere to the conduits1 pipes or gas passages1 is best removed while the apparatus is still hot1 or a solvent may be employed1 such as kerosene1 turpentine1 etc4 ,the connections between the vaporizer and the scrubber are particularly liable to become obstructed by the accumulation of tar or dust carried along by the gas4 ,it is advisable to examine the several parts of the plant once or twice a week by opening the covers or the cleaning-plugs4 ,the lower compartment of the washer keeps back the greater part of the dust which has not been retained in collectors or boxes provided especially for this purpose4 ,the dust takes the form of slime1 and1 in some arrangements of apparatus1 tends to clog up the overflow pipe1 thus arresting the passage of gas and causing the engine to stop4 ,this portion of the washer should be thoroughly cleaned once or twice a month4 ,if very hard blast-furnace coke is used in the washer1 it may be kept in use for over a year without requiring removal4 ,in order to free the purifying materials from dust and lime sediments carried along by the wash-water1 it is well to let the wash-water flow as abundantly as possible for about a half-hour at least once a month4 ,at the time of renewing the purifying material the precautions indicated in the section dealing with these matters should be observed1 and care should be taken to have shelves or gratings on which the material is supported in layers not too thick1 so as to avoid any resistance to the passage of the gas4 ,in a general way it is advisable to test the drain-cocks on the several apparatus daily1 and to keep them in perfect condition4 ,if1 when open1 one of these cocks does not discharge any gas1 water1 or steam1 a wire should be introduced into the bore to make sure it is not clogged up4 ,care of the ,apparatus4--,each producer-gas plant will require special instructions for running it1 according to the system1 the construction1 and the size of the plant4 ,such instructions are generally furnished by the manufacturer4 ,however1 there are some general rules which are common to the majority of suction gas-producers1 and these will here be enumerated4 ,starting the ,fire for the ,gas ,generator4--,this operation calls for the presence of the engineer of the plant and an assistant4 ,the proper procedure is as follows3 ,first3 ,open the doors of the furnace and of the ash-pit4 ,then open the outlet flue and make sure that the grate of the generator is clear of ashes and clinkers4 ,it should also be seen to that the parts of the charging-box work well and that the joints are tight4 ,second3 ,ascertain whether there is the proper amount of water in the vaporizer1 in the scrubber1 etc41 and that the feed works properly4 ,third3 ,through the door of the combustion-chamber introduce straw1 wood shavings1 cotton waste1 etc42 light them and fill the generator with dry wood up to one-quarter or one-half of its height2 then add a few pailfuls of coal4 ,fourth3 ,close the doors of the ash-pit and of the combustion-chamber and start the draft by means of the fan4 ,as soon as the draft is started1 it must be kept up without interruption until the engine begins to run1 which may be ten or twenty minutes after lighting the fire4 ,fifth3 ,after the draft has been continued for a few minutes1 the coal becomes sufficiently incandescent to start the production of gas1 which may be ascertained by trying to light the gas at the test-cock near the generator4 ,then the opening in the outlet flue is half closed for the purpose of producing pressure in the apparatus4 ,sixth3 ,open the outlet flue adjacent to the engine for the purpose of purging the apparatus and the conduits of the air which they contain until the gas may be lighted at the test-cock placed near the motor4 ,seventh3 ,adjust the normal outflow of wash-water for the scrubber4 ,eighth3 ,as soon as the gas burns continuously at the test-cock with an orange-colored flame the engine may be started4 ,the gas at first burns with a blue flame2 this color indicates that it contains a certain amount of air4 ,the opening of the test-cock should be so regulated as to reduce the outlet pressure of the gas sufficiently to prevent the flame from going out4 ,during the production of the draft1 as well as during the ordinary running of the plant1 the filling of the apparatus with fuel should be done with care to prevent explosions of gas due to the entrance of air4 ,particular care should be taken never to open at the same time the lid of the charging-box and the device1 be it a cock1 valve1 or damper1 which controls the connection of the charging-box with the generator4 ,all the operations which have been mentioned above should be carried out as quickly as possible4 ,,starting ,,the ,,engine ,the manner of starting the engine depends on the type of the engine and on the starting device with which it is provided1 as we have already explained in connection with engines working with gas from city mains4 ,it is1 however1 important for the production of a good explosive mixture to regulate the amount of air supplied to the engine according to the quality of the gas employed4 ,it is advisable to continue the operation of the fan until several explosions have taken place in the cylinder and the engine has acquired a certain speed so as to be able to draw in the normal amount of gas4 ,naturally the gas-outlet tube near the admission-cock should be closed after starting the engine1 as well as the opening in the outlet flue of the generator4 ,when the motor is running properly1 the amount of water fed to the vaporizer and overflowing to the ash-pit is properly adjusted4 ,the generator is then filled up to the level indicated by the manufacturer4 ,care of the ,generator during ,operation4--,as soon as the apparatus is running under normal conditions1 it presents the advantage of requiring only very slight supervision and very little manual tending4 ,the supervision consists3 ,first3 ,in regulating and keeping up a proper feed of water to the vaporizer4 ,second3 ,in seeing to it that in apparatus provided with an overflow leading to the ash-pit1 the water should flow constantly but without exceeding the proper amount4 ,third3 ,in keeping down temperature in the scrubber by properly regulating the feed of the wash-water4 ,this apparatus may be slightly warm at its lower part1 but must be quite cold at the top4 ,the manual tending to be done is limited to the regular filling up of the generator with fuel and to the removal of ashes and clinkers4 ,the charging is effected at regular intervals1 which1 according to the various types of anthracite-generators1 vary from one to six hours4 ,charging the apparatus at short intervals entails unnecessary labor1 while charging at too long intervals will often interfere with the uniform production of the gas4 ,it will be obvious that the amount of fuel introduced will be the larger1 the greater the intervals between two fillings4 ,this fuel is cold and contains between its particles a certain amount of air2 furthermore1 the layer of coal which covers the incandescent zone has become relatively thin4 ,the excess of air impoverishes the gas1 and the fresh fuel lowers the temperature of the mass undergoing combustion1 so that again the gas in process of formation is weakened4 ,experience seems to show that as a rule it is best to fill up the generator at intervals of from two to three hours1 according to the work done by the engine4 ,it should be noted that the level of the fuel in the generator should not sink below the bottom of the feed-hopper4 ,the author wishes again to emphasize that in order to prevent the harmful entrance of air1 the charging operations should be carried out as quickly as possible2 and for this reason the fuel should be introduced not by means of the shovel1 but by means of a pail1 scuttle1 or other appropriate receptacle4 ,care should be taken to fill the charging box to its upper edge and to adjust its cover accurately before operating the device which closes the feed-hopper 7valve1 cock74 ,the removal of the ashes and clinkers should be accomplished as infrequently as possible1 since opening the doors of the ash-pit and of the combustion-chamber necessarily causes an inward suction of cold air which is harmful4 ,as a rule with generators employing anthracite coal1 it is sufficient to empty the ash-pit twice daily2 this should be preferably done during stoppages4 ,however1 the cleaning of the grate by means of a poker passed between the grate-bars or over them in order to bring about the falling of the ashes1 should be attended to every two to four hours1 according to the type of the generator and the nature of the fuel4 ,in order that this cleaning may be done without opening the doors1 the latter should be provided with apertures having closing devices4 ,this cleaning has for its chief object to allow the free passage of the air for supporting combustion and to keep the incandescent zone in the apparatus at the proper height4 ,the accumulation of ashes and clinkers at the bottom of the retort will shift this zone upward and impair the quality of gas4 ,stoppages and ,cleaning4--,after closing the gas-inlet to the engine1 the damper in the gas-outlet flue of the generator should be opened and the cocks controlling the feed of water to the scrubber and to the vaporizer should be closed4 ,if it is desired to keep up the fire of the generator during the stoppage so as to be able to start again quickly1 the ash-pit door should be opened so as to produce a natural draft which will maintain combustion4 ,while the door is open1 the clinkers which have accumulated above the grate may be removed1 as they are much more easily taken off the grate when they are hot4 ,at least once a week the fire in the generator should be put out and the generator completely cleaned--that is1 when ordinary fuel is employed4 ,for this purpose1 as soon as the apparatus is stopped1 a portion of the incandescent fuel is withdrawn through the doors of the combustion-chamber1 and the retort is allowed to cool before it is emptied entirely4 ,too sudden a cooling of the retort may injure its refractory lining4 ,in order to prevent explosions caused by the entrance of air1 the feed-hopper should remain hermetically closed during the removal of the incandescent fuel through the doors of the combustion-chamber4 ,if the apparatus is placed in a room poorly ventilated1 the cleaning should be attended to by two men1 so that one may assist the other in case he is overcome by the gas4 ,in all cases there should be a strict prohibition against the use of any light having an exposed flame liable to set on fire the explosive mixtures which may be formed4 ,when the generator1 after cooling1 is completely open1 the charging-box is taken apart1 and1 if necessary1 the feed-hopper also2 the grates are taken out1 if necessary2 and1 by means of a poker inserted from above1 the clinkers and slag adhering to the retort are broken off4 ,in the foregoing paragraphs the author has indicated how the several apparatus1 such as the vaporizer1 the washer1 the conduits1 etc41 should be attended to and maintained in good working order4 ,,chapter ,,xiv ,,oil ,,and ,,volatile ,,hydrocarbon ,,engines ,although this book is devoted primarily to a discussion of street-gas and producer-gas engines employed in various industries1 a few words on oil and volatile hydrocarbon engines may not be out of place4 ,oil-engines are those which use ordinary petroleum as a fuel or illuminating oil of yellowish color1 having a specific gravity varying from #j4hjj to #j4hbj at a temperature of #ae degrees ,c4 7#ei degrees ,f471 and boiling between #adj and #ade degrees ,c4 7#bhd to #big degrees ,f474 ,volatile hydrocarbon engines are those which employ light oils obtained by distilling petroleum4 ,these oils are colorless1 have a specific gravity that varies from #j4fhj to #j4gbj1 and boil between #hj degrees and #aae degrees ,c4 7#agf to #beg degrees ,f474 ,among these essences1 as they are called in ,europe1 may be mentioned benzine and alcohol4 ,in general appearance1 and the way in which they are controlled1 oil-engines differ but little from gas-engines4 ,their usual speed1 however1 is #bj to #cj per cent4 greater than that of gas-engines4 ,except in some engines of the ,diesel and ,banki types1 the compression does not exceed #dc to #ga pounds per square inch4 ,in volatile hydrocarbon engines1 on the other hand1 the speed is very high1 often running from #ejj to #b1jjj revolutions per minute1 while the speed of gas or oil engines rarely exceeds #bej or #cjj revolutions per minute4 ,oil-,engines4--,oil-engines are employed chiefly in ,russia and in ,america4 ,because of the high price of oil in other countries they are to be found only in small installations in country regions and are used mainly for driving locomobiles and launches4 ,the improvements which have been made of late years in the construction of gas-engines supplied by suction gas-producers for small as well as for large powers1 have hindered the general introduction of oil-engines4 ,the characteristic feature in the design of many of the oil-engines of the four-cycle type now in use 7to which type we shall confine this discussion7 is to be found in the controlling mechanism employed4 ,the underlying principle of this mechanism lies not in acting upon the admission-valve1 but in causing the governor to operate the exhaust-valve in such a manner that it is held open whenever the engine tends to exceed its normal speed4 ,some engines1 however1 are built on the principle of the gas-engine1 with an admission-valve so controlled by the governor that it is open during normal operation and closed whenever the speed becomes excessive4 ,the necessity of producing a mixture of air and oil capable of being ignited in the engine-cylinder has led to the invention of various contrivances1 which cannot be used if illuminating-gas or producer-gas be employed4 ,these contrivances are the atomizer1 the carbureter1 the oil-pump1 the air-pump1 the oil-tank1 and the oil-lamp4 ,in some oil-engines all of the elements may be found1 but for the purpose of simplifying the construction and of avoiding unnecessary complications1 manufacturers devised arrangements which rendered it possible to discard some of them1 particularly those of delicate construction and operation4 ,it is not the intention of the author to enter into a detailed description of these various devices1 since the limitations of this book would be considerably surpassed4 ,the reader is referred to books on the oil-engine1 published in the ,united ,states1 ,england1 and ,france4,b ,most of the observations which have been made on the construction and installation of gas-engines1 as well as the precautions which have been advised in the conduct of an engine1 apply with equal force to oil-engines4 ,it will therefore be unnecessary to recur to this phase of the subject so far as oil-engines are concerned4 ,one point only should be insisted upon--the necessity of very frequently cleaning the valves and moving parts of the engine4 ,illuminating-oil when burnt produces sooty deposits1 particularly if combustion be incomplete1 which deposits foul the various parts and cause premature ignitions and faulty operation4 ,the use of oil in atomizers1 carbureters1 and lamps is accompanied with the employment of pipes and openings so small in cross-section that the slightest negligence is attended with the formation of partial obstructions that inevitably affect the operation of the engine4 ,volatile ,hydrocarbon ,engines4--,only those engines will here be treated which have become of importance in the development of the automobile4 ,some designers have attempted to employ the volatile hydrocarbon engine for industrial and agricultural purposes1 and have devised electro-generator groups1 hydraulic groups1 and so-called industrial combinations in which belt and pulley transmission is employed4 ,these applications in particular will here be rapidly reviewed4 ,the high speed at which engines of this class are driven renders it possible to operate a centrifugal pump directly and to mount both the engine and machine which it actuates on the same base4 ,the hydrocarbon engine has the merit of being very light and of taking up but little room4 ,its cost is considerably less than that of an oil or producer-gas engine of corresponding power4 ,on the other hand1 its maintenance is much more expensive1 and the hydrocarbons upon which it depends for fuel anything but cheap4 ,furthermore1 the engines wear away rapidly1 on account of their high speed4 ,for this reason it is advisable to base calculations on a life of three to four years1 while oil and gas engines may generally be considered to be still of service at the end of thirteen years4 ,on the following page a comparison of costs for installation and maintenance is drawn between the oil and hydrocarbon engine on the basis of ten horse-power4 ,comparative ,costs4--,a #aj horse-power oil-engine1 in the matter of first cost of installation1 is about #ce per cent4 more expensive than a volatile hydrocarbon engine of equal power4 ,on the other hand1 the operating expenses of the oil-engine are less by #be per cent4 than they are for the volatile hydrocarbon engine4 ,the engines which are here discussed usually have their cylinders vertically arranged1 as in steam-engines of the overhead cylinder type4 ,the crank-shaft and the connecting-rods are enclosed in a hermetically sealed box filled with oil1 so that the movement of the parts themselves ensures the liberal lubrication of the piston4 ,the suction-valve is generally free1 although latterly designers have shown a tendency to connect it with the cam-shaft1 with the result that it has become possible to reduce the speed appreciably without stopping the engine4 ,the carbureter is operated by the suction of the engine4 ,if the fuel employed is alcohol1 it must be heated4 ,tests of ,high-speed ,engines4--,high-speed engines present various difficulties which must be contended with in controlling their operation4 ,their high speed renders it impossible to take indicator records as in the case of most industrial engines4 ,indicator cards1 moreover1 at best give but very crude data1 which relate to each explosion cycle only1 and which are therefore inadequate in determining the exact conditions of an engine's operation4 ,oil1 benzine1 and other so-called carbureted-air engines are particularly difficult to control because of many phenomena which cannot be recorded4 ,in order to test the operation of high-speed engines1 two different types of instruments are at present employed3 the manograph and the continuous explosion recorder4 ,the ,manograph4--,the manograph1 which is the invention of ,hospitalier1 is an optical instrument in which a series of closed diagrams are superimposed upon a polished mirror similar in form to ,watt diagrams4 ,because the images persist in affecting the retina of the eye an absolutely continuous1 but temporary1 gleam is seen4 ,still1 it is possible to obtain a photograph or a tracing of these diagrams4 ,the ,continuous ,explosion ,recorder for ,high-speed ,engines4--,the author has devised an explosion and pressure recorder1 which is mounted upon the explosion chamber to be tested and which communicates with the chamber through the medium of a cock r 7,fig4 #acf74 ,the instrument is somewhat similar in form to the ordinary indicator4 ,its record1 however1 is made on a paper tape which is continuously unwound4 ,the cylinder c is provided with a piston p1 about the stem of which a spring s is coiled4 ,a clock train contained in the chamber b unwinds the strip of paper from the roll p' and draws it over the drum p''1 where the pencil t leaves its mark4 ,the tape is then rewound on the spindle p'''4 ,a small stylus or pencil f traces the atmospheric line on the paper as it passes over the drum p''4 ,in order to obviate the binding of the piston p when subjected to the high temperature of the explosions1 the cylinder c is provided with a casing e in which water is circulated by means of a small rubber tube which fits over the nipple e'4 ,this recorder analyzes with absolute precision the work of all engines1 whatever may be their speed4 ,it gives a continuous graphic record from which the number of explosions1 together with the initial pressure of each1 can be determined1 and the order of their succession4 ,consequently the regularity or irregularity of the variations can be observed and traced to the secondary influences producing them1 such as the section of the inlet and outlet valves and the sensitiveness of the governor4 ,it renders it possible to estimate the resistance to suction and the back pressure due to expelling the burnt gases1 the chief causes of loss in efficiency in high-speed engines4 ,furthermore1 the influence of compression is markedly shown from the diagram obtained4 ,illustration3 ,,fig4 #acf4--,r4 ,mathot's continuous explosion recorder4 ,illustration3 ,,fig4 #acg4--ab ,h4,p4 ,oil-engine4 ,illustration3 ,,fig4 #ach4--f ,h4,p4 ,volatile ,hydrocarbon ,engine4 ,illustration3 ,,fig4 #aci4--;,effect of size of section and exhaust ports4 ,the recorder is mounted on the engine2 its piston is driven back by each of the explosions to a height corresponding with their force2 and the stylus or pencil controlled by the lever t records them side by side on the moving strip of paper4 ,the speed with which this strip is unwound conforms with the number of revolutions of the engine to be tested1 so that the records of the explosions are placed side by side clearly and legibly4 ,their succession indicates not only the number of explosions and of revolutions which occur in a given time1 but also their regularity1 the number of misfires4 ,the atmospheric pressure of the explosions is measured by a scale connected with the recorder-spring4 ,by employing a very weak spring which flexes at the bottom simply by the effect of the compression in the engine-cylinder1 it is possible to ascertain the amount of the resistance to suction and to the exhaust4 ,it is simply sufficient to compare the explosion record with the atmospheric line1 traced by the stylus f4 ,by means of this apparatus1 and of the records which it furnishes1 it is possible analytically to regulate the work of an engine1 to ascertain the proportion of air1 gas1 or hydrocarbon1 which produces the most powerful explosion1 to regulate the compression1 the speed1 the time of ignition1 the temperature1 and the like 7,figs4 #acg1 #ach and #aci74 ,in order to explain the manner of using this recorder several specimen diagrams are here given4 ,i4 ,determination of the ,amount of ,compression4--,a spring of average power is employed1 the total flexion of which corresponds almost with the maximum compression so as to obtain a curve of considerable amplitude4 ,the engine is first revolved without producing explosions1 driving it from the dynamo usually employed in shops1 at the different speeds to be studied4 ,the compression of the mixture varies in inverse ratio to the number of revolutions of the shaft1 owing to the resistances which are set up in the pipes and the valves and which increase with the speed4 ,the accompanying cut 7,fig4 #adj7 shows two distinct records taken in two different cases1 namely3 ,a4--,speed of engine1 #iej revolutions per minute2 amount of compression1 #fh4i pounds per square inch4 ,b4--,speed of engine1 #a1ejj revolutions per minute2 amount of compression1 #fa pounds per square inch1 or #aa4e per cent4 less4 ,illustration3 ,,fig4 #adj4 ,,ii4 ,determination of the ,resistance to ,suction and ,exhaust4--,influence of the tension of the spring of the suction valve and of the section of the pipe4 ,effect of the section of the exhaust-valve and of the length and shape of the exhaust-pipe3 ,a very light spring is utilized1 the travel of which is limited by a stop so as to obtain on a comparatively large scale the depressions and resistance respectively represented by the position of the corresponding curve1 above or below the atmospheric line 7,fig4 #ada74 ,illustration3 ,,fig4 #ada4 ,c4--,tension of the suction-valve3 #b4i pounds4 ,resistance to suction3 #a_/g of an atmosphere 7#b4g pounds74 ,d4--,tension of the suction-valve3 #b4ag pounds4 ,resistance to suction3 #b_/g of an atmosphere 7#e4d pounds74 ,e4--,a chest is used for the exhaust4 ,resistance to exhaust3 #b_/g of an atmosphere 7#e4d pounds74 ,f4--,the exhausted gases are discharged into the air1 the pipe and the chest being discarded4 ,resistance to the exhaust is zero 7,fig4 #adb74 ,illustration3 ,,fig4 #adb4 ,the depression graphically recorded is partly due to the inertia of the spring of the explosion-recorder1 which spring expands suddenly when the exhaust is opened4 ,,iii4 ,comparison of the ,average ,force of the ,explosions by ,means of ,ordinates4--,a powerful spring is employed4 ,the paper band or tape of the recorder is moved with a small velocity of translation so as to approximate as closely as possible the corresponding ordinates representing the explosions 7,fig4 #adc74 ,illustration3 ,,fig4 #adc4 ,g4--,pure alcohol4 ,explosive force1 #cfi4gb to #dbf4f pounds per square inch4 ,h4--,carbureted alcohol4 ,explosive force1 #cig4f to #eaj4h pounds per square inch4 ,i4--,volatile hydrocarbon4 ,explosive force1 #dhc4dh to #eca4ib pounds per square inch4 ,,iv4 ,analysis of a ,cycle by ,means of ,open ,diagrams ,representing the ,four ,periods4--,a powerful spring is employed1 and the paper is moved with its maximum speed of translation4 ,the four phases of the cycle are easily distinguished as they succeed one another graphically from right to left in other words1 in a direction opposite to that in which the paper is unwound4 ,a diagram is made which reproduces exactly the values of the corresponding pressures at different points in the travel of the piston 7,fig4 #add74 ,the periods of the cycle are reproduced as faithfully as if the ordinary indicator which gives a closed curved diagram had been employed4 ,there is no difficulty in reading the record1 since the paper is not in any way connected with the engine-piston4 ,some attempts have been made to secure open diagrams in which the motion of translation given to the paper is controlled by the engine itself2 but these apparatus as well as the ordinary indicators cannot be used when the speed of the engine exceeds #djj to #ejj revolutions per minute4 ,illustration3 ,,fig4 #add4 ,j4--,speed1 #a1bjj revolutions2 carbureted alcohol2 average force of the explosions1 #dbf4f pounds per square inch4 ,average compression1 #ib4dc pounds per square inch4 ,pressure at the end of the expansion1 #ba4cc pounds per square inch4 ,v4 ,analysis of the ,inertia of the ,recorder4 ,selection of the ,spring to be ,employed4--,given the rapidity with which the explosions succeed one another in automobile engines1 it is readily understood that the inertia of the moving parts of the recorder will be graphically reproduced 7,fig4 #add74 ,the effect of this inertia is a function of the weight of the moving parts and of the extent of their travel4 ,the moving masses are represented by the piston and its rod1 the spring and the levers of the parallelogram stylus4 ,the effects due to inertia have been considerably lessened by reducing the weight of the various parts to a minimum4 ,a hollowed piston1 a hollowed rod and short and light levers have been adopted4 ,the traditional pencil has been displaced by a silver point which traces its mark upon a metallically coated paper4 ,for the heavy springs with their long travel1 light but powerful springs with small amplitudes have been substituted4 ,since the perfect lubrication of the recorder-cylinder is of great importance1 a simple oiling device certain in its action has been adopted4 ,the recess of the piston forms a cup that can be filled with oil whenever the spring is changed4 ,at each explosion the violent return of the piston splashes oil against the cylinder walls and thus insures perfect lubrication4 ,it should be observed that if the directions given are not followed1 particularly in the choice of a spring suitable for each experiment1 inertia effects will be produced4 ,these can easily be detected on the record and cannot be confused with the curves which interpret the phenomena occurring in the cylinder of the engine4 ,at a height equal to the end of the piston's stroke1 the cylinder of the recorder is provided with a water-jacket which keeps the temperature down to a proper point and prevents the binding of the piston4 ,the explosion-chamber of automobile engines being rather small in volume1 should not be sensibly increased in order that the record obtained may conform as nearly as possible with actual working conditions on the road4 ,in order to attain this end the cylinder of the recorder is so disposed that the piston travels to the height of the connecting-cock4 ,as a result of this arrangement the field of action of the gases is reduced to a minimum4 ,since these gases have no winding path to follow1 they are subjected neither to loss of quantity nor to cold4 ,,footnotes3 ,b ,hiscox1 ,gas and ,oil ,engines1 ,norman ,w4 ,henley ,pub4 ,co41 ,new ,york4 ,parsell and ,weed1 ,gas and ,oil ,engines1 #aijj1 ,norman ,w4 ,henley ,pub4 ,co41 ,new ,york4 ,goldingham1 #aijj1 ,spon ,chamberlain1 ,london4 ,dugald ,clerk1 #ahig1 ,longmans1 ,london4 ,grover1 #aijb1 ,heywood1 ,manchester4 ,aime4 ,witz1 #aijd1 ,barnard1 ,paris4 ,h4 ,gueldner1 #aijc1 ,springer1 ,berlin4 ,,chapter ,,xv ,,the ,,selection ,,of ,,an ,,engine ,the conditions which must be fulfilled both by engines and gas-producers in order that they may industrially operate with regularity and economy have been dwelt upon at some length4 ,unfortunately it often happens that engines are not installed as they should be1 with the result that they run badly and that the reputation of gas-engines suffers unjustly4 ,the use of suction gas-producers in particular caused considerable trouble at first owing to inexperience1 so that even now many hesitate to adopt them despite their great economical advantages4 ,the reason assigned for this hesitation is the supposed danger attending their operation4 ,the factory proprietor who intends to install a gas-engine in his plant is not usually able to appreciate the intrinsic value of one engine when compared with another1 or to determine whether the plans for an installation conform with the best practice4 ,the innumerable types of engines offered to him by manufacturers and their agents1 each of whom claims to have a better engine than his rivals1 plunges the purchaser into hesitation and doubt4 ,not knowing which engine to select1 he usually buys the cheapest4 ,very often he learns1 as time goes by1 that his installation is far from being perfect4 ,finally he begins to believe that he ought to consult an expert4 ,the author's personal experience has convinced him that eight times out of ten the factory owner who has picked out an engine for himself has not obtained an installation which meets the requirements which the manufacturers of gas-engines should fulfil4 ,many of these requirements could be complied with were it not for the fact that the manufacturer has dropped certain details which appeared superfluous1 but which were in reality very important in obtaining perfect operation4 ,the author therefore suggests that the services of a competent expert be retained by those who intend to install a gas-engine in their plants4 ,the ,duty of a ,consulting ,engineer4--,an expert fills the same office as an architect1 and impartially selects the engine best suited to his client's peculiar needs4 ,his examination of the engines offered to him will proceed somewhat according to the following programme3 #a4 ,he will first study the installation from the mechanical point of view1 and also the local conditions under which that installation is to operate1 in order that he may not order an engine too large or too small1 or a type incompatible with the foundations at his disposal1 or unable to fulfil all the requirements of his client4 #b4 ,he will examine the precautions which have been taken to avoid or reduce to a minimum certain inconveniences which attend the operation of explosion-engines4 #c4 ,he will draw up specifications1 with the terms of which gas-engine makers must comply1 so that he can compare on the basis of these specifications the merits of the engines submitted to him4 #d4 ,he will prepare an estimate of cost and also a contract which is not couched in terms altogether in the gas-engine maker's favor1 and which gives the purchaser important warranties4 #e4 ,he will supervise the technical installation of the engine or plant4 #f4 ,he will make tests after the engine is installed and see to it that the maker has fulfilled his warranties4 ,specifications4--,since engines and gas-producers are constructed for commercial ends1 it naturally follows that their manufacturers seek to make the utmost possible profit in selling their installations4 ,prices charged will necessarily vary with the quality of material employed1 the care taken in constructing the engine and generator1 the number of apparatus of the same type which are manufactured1 the arrangement of the parts and that of the installations4 ,since there is considerable rivalry among gas-engine builders1 selling prices are often cut down so far that little or no profit is left4 ,it is very difficult--indeed impossible--to convince a purchaser that it is to his interest to pay a fair price in order to obtain a good installation1 especially when other manufacturers are offering the same installation at a less price with the same warranties4 ,as a result of this state of affairs1 engine builders1 in order that they may not lose an order1 are willing1 to reduce their prices1 hoping to make up in the quality of the workmanship and the material what they would otherwise lose4 ,often they will deliver an engine too small in size but operating at a higher speed than that ordered2 or they will select an old type1 or carry out certain details with no great care4 ,this1 to be sure1 is not always the case2 for there are a few builders of engines who place their reputation above everything else and who would rather lose an order than execute it badly4 ,others1 unfortunately1 prefer to have the order at all costs4 ,by retaining a consulting engineer1 all these difficulties are overcome4 ,in the first place1 the engineer draws up a scale of prices and specifications which must be complied with in their entirety as well as in all details4 ,rival engine builders are thus compelled to make their estimates according to the same standard1 so that one engine can readily be compared with another with the utmost fairness4 ,in these specifications1 penalties will be provided for by the engineer which will be levied if the warranties of the maker are not fulfilled4 ,otherwise the warranties are worth nothing4 ,the first consequence of engaging a consulting engineer is to render the matter of cost a secondary one4 ,a factory owner who employs a consulting engineer and pays him for his services1 is impelled chiefly by the desire to obtain a good installation which will perform what he expects of it4 ,for that reason necessary sacrifices will be made to comply with the client's wishes4 ,if the purchaser considers the question of cost most important to him1 he need not engage an expert to supervise the installation of his engines4 ,he has simply to pick out the cheapest engine4 ,unfortunately1 however1 the money which he will save by such a procedure will be more than compensated for by the trouble which he will later experience when his motor stops or when it breaks down1 because it has been cheaply built in the first place4 ,the advice of a consulting engineer is therefore of importance to the purchaser1 because an engine will be installed which will in every way meet his requirements4 ,the gas-engine builder will also prefer to deal with an engineer1 because the engineer can appreciate at their true worth good material and good workmanship and place a fair valuation upon them4 ,the specifications of a gas-engine and gas-producer expert are accepted by most engine builders1 because an expert will not introduce conditions which cannot be fulfilled4 ,some manufacturers refuse to consider the conditions imposed by specifications seriously1 or else they fix different prices and make tenders on the basis of these with or without specifications4 ,in either case the purchaser may be sure that he is not receiving what he has a right to exact4 ,testing the ,plant4--,when the engine has been selected the consulting engineer supervises its installation1 and1 after this is completed1 carries out tests in order to determine whether or not the guaranteed power and consumption are attained4 ,the methods employed in testing a gas-engine are both complex and delicate4 ,the quality of the gas1 the proportions of the elements forming the mixture1 the time and the method of ignition1 the temperature of the cylinder-walls1 the temperature and the pressure of the gas drawn into the cylinder1 all these are factors which have a decided bearing upon the results of a test4 ,if these factors be not carefully considered the conclusions to be drawn from the test may be absolutely wrong4 ,indicators of any type should not be indiscriminately employed2 only those specially designed for gas-engine purposes should be used4 ,indicator cards are in themselves inadequate1 and should be supplemented by the records of explosion-recorders4 ,the calorific value of the gas should be measured either by the ,witz apparatus or by means of any other calorimeter4 ,in interpreting the diagrams and records some difficulty will be encountered4 ,sometimes it happens that a particular form of curve is attributed to a cause entirely different from the real one4 ,it happens not infrequently that engineers1 whose experience is confined to engines of one make and who have not had the opportunity to make sufficient comparisons1 draw such erroneous conclusions from cards4 ,to recapitulate what has already been said1 the testing of gas-engines requires considerable experience and cannot be lightly undertaken4 ,special instruments of precision are necessary4 ,the author has very often been called upon to contradict the results obtained by experts whose tests have consisted simply in ascertaining the engine power either by means of a ,prony brake1 or by means of a brake-strap on the fly-wheel4 ,the brake gives but crude results at best2 it is a means of control1 and not an instrument of scientific investigation4 ,something more than the mere power produced by an engine should be ascertained4 ,the tests made should throw some light upon the reasons why that power cannot be exceeded1 and show that the necessary changes can be made to cause the engine to operate more economically and to yield energy of an amount which its owner has a right to expect4 ,the indicator and the recorder are testing instruments which clearly indicate discrepancies in operation and the means by which they may be corrected4 ,the tests made should determine whether the power developed is not obtained largely by means of controlling devices which cause premature wearing away of the engine parts4 ,it is not the intention of the author to describe indicators of the well-known ,watt type4 ,it is simply his purpose to call attention to the explosion-recorder which he has devised to supplement the data obtained by means of the indicator4 ,illustration3 ,,fig4 #ade4--,mathot explosion-recorder4 ,explosion-,recorder for ,industrial ,engines4--,the explosion-recorder illustrated in ,fig4 #ade can be adapted to any ordinary indicator4 ,it is composed of a supporting bracket ,b upon which a drum ,t is mounted4 ,this drum is rotated by a clock-train1 the speed of which is controlled by means of a special compensating governor4 ,the entire system is pivotally mounted upon the supporting screw ,o1 so that the drum ,t1 about which a band of paper is wound1 may be swung against a stylus ,c1 which records upon the paper the number and power of the explosions4 ,these explosions are measured according to scale by a spring connected with an indicator4 ,the records obtained disclose for any given cycle the amount of compression as well as the force of the explosion1 and render it possible to study the phenomena of expansion1 exhaust1 and suction4 ,they are1 however1 inadequate in showing exactly how an engine runs in general4 ,indeed1 in most gas-engines1 as well as oil and volatile hydrocarbon engines1 each explosion differs from that which follows in character and in power2 and it is absolutely essential to provide some means of avoiding these variations4 ,the explosion-recorder gives a graphic record from which the number of explosions can be read1 and also the initial pressure of each explosion1 the number of corresponding revolutions1 the order in which the explosions succeed one another1 and consequently the regularity of certain phenomena caused by secondary influences1 such as the section of the distributing members1 the sensitiveness of the governor1 and the like4 ,the explosion-records can be taken simultaneously with ordinary diagrams4 ,in order to attain this end1 the recorder is allowed to swing around the pivot ,o1 so that the drum carrying the paper band is brought into engagement1 or swung out of engagement with the stylus1 as it is influenced by each explosion1 thereby leaving its record on the paper4 ,the ordinary diagram may be traced on the drum of the indicator1 as it continues to operate in its usual way4 ,thus the explosion-recorder renders it possible to control the operation of engines1 to obtain some idea of the cause of defects and to attribute them to the proper force4 ,improvements can then be made which will ensure a greater efficiency4 ,a number of records herewith reproduced illustrate the defects in the controlling apparatus and in the construction of certain engines1 and also the result of improvements which have been made on the basis of the records obtained4 ,the smaller lines indicate the compression1 which is usually constant in engines in which the hit-and-miss system of governing is employed1 while the larger lines indicate the explosions4 ,these records are only part of the complete data normally drawn on the paper in the period of #abj seconds corresponding with an entire revolution of the recorder-drum4 ,illustration3 ,,fig4 #adf4--,record with automatic starter4 ,illustration3 ,,fig4 #adg4--;,gas-engine running at one-half load4 ,illustration3 ,,fig4 #adh4--,record made after correcting faults4 ,illustration3 ,,fig4 #adi4--,record made after correcting faults4 ,the first record was taken while starting up an engine provided with an automatic starting device and supplied with explosive mixture without previous compression 7,fig4 #adf74 ,the gradual lessening of the distances of the ordinates or lines representing the explosions shows that the speed of the motor was slowly increasing1 and also indicates the time which elapsed before the engine was running smoothly4 ,the records that follow 7,figs4 #adg1 #adh and #adi7 show the results which can be obtained with the recorder by correcting the errors due to faults in installing the engine and its accessories4 ,the fifth record is particularly interesting because it shows the influence of the ignition-tube on the power of the deflagration of the explosive mixture 7,fig4 #aej74 ,this record was obtained with an engine provided with two contiguous tubes4 ,the communication of each of these tubes with the explosion-chamber could be cut off at will at any moment4 ,the last record 7,fig4 #aea7 was obtained at a time when the effective load of the engine was changed at two different intervals4 ,this record shows how regularly the engine was running and how constant were the initial pressures4 ,these pressures1 however1 which is the case in most engines1 manifestly diminish when the explosions succeed one another without idle strokes of the piston4 ,this shows1 also1 the influence of scavenging the products of combustion and the effect it has on the efficiency of explosion-engines4 ,analysis of the ,gases4--,it has already been stated that one of the tests which should be made consists in measuring the calorific value of the gas4 ,just what the calorific value of the gas may be it is necessary to know in order to obtain some idea of the thermal efficiency of the installation4 ,if a suction gas-producer be employed 7an apparatus in which the nature of the gas generated changes at each instant71 calorimetrical analyses are indispensable in appreciating the conditions under which a generator operates4 ,these analyses are made by means of calorimeters which give the calorific value either at a constant pressure or at a constant volume4 ,constant-volume instruments give a somewhat weaker record than constant-pressure instruments2 but according to ,professor ,aime ,witz1 the inventor of an excellent calorimeter1 the constant-volume type is almost indispensable in gaging the efficiency of explosion-engines4 ,illustration3 ,,fig4 #aej4 ,illustration3 ,,fig4 #aej;b4 ,illustration3 ,,fig4 #aea4--,record made when effective load was changed at two different intervals4 ,illustration3 ,,fig4 #aeb4--,the ,witz calorimeter4 ,the ,witz ,calorimeter4--,the accompanying diagram 7,fig4 #aeb7 illustrates ,professor ,witz's instrument4 ,its elements are a steel cylinder having an interior diameter of #b4cf inches1 about a thickness of #j4jgh inch and a height of about #c4ed inches1 so that its capacity is about #ae4a cubic inches1 and two covers screwed on the cylinder to seal it hermetically1 oiled paper being used as a washer4 ,the upper cover carries a spark-exciter2 the lower cover is provided with a valve which discharges into a cylindrical member #a4jf inches in diameter4 ,this second cover is downwardly inclined at its circumference toward the center to insure complete drainage of the mercury used for charging the calorimeter4 ,all surfaces are nickel plated4 ,the proportions of nickel and of steel are fixed by the manufacturer so as to render it possible to calculate the displacement of the apparatus in water4 ,the calorimeter having been completely filled with mercury is inverted in this liquid in the manner of a test tube4 ,the explosive mixture is then introduced1 being fed from a bell in which it has previously been prepared4 ,a rubber tube connects the bell with the instrument4 ,the gas is forced from the bell to the calorimeter by the pressure in the bell4 ,the conical form of the bottom causes the calorimeter to be emptied rapidly and to be refilled completely with explosive gas at a pressure slightly above that of the atmosphere4 ,equilibrium is re-established by manipulating the valve1 during a very short interval1 so as to permit the excess gas to escape4 ,during this operation the calorimeter must be maintained in the vertical position shown in the diagram4 ,the atmospheric pressure is read off to one-tenth of a millimeter 7#j4jjcicf inches7 on a barometer4 ,the temperature of the gas may be taken to be that of the mercury-vessel4 ,the explosive mixture is prepared in the water reservoir1 the glass bulb shown in the accompanying illustration being employed4 ,this bulb is closed at its upper end by means of a cock and is tapered at its lower end4 ,the gas or air enters at the top by means of a rubber tube and gradually displaces the water through the lower end4 ,the bulbs have a volume varying from #bjj to #ejj cubic centimeters 7#ab to #cj cubic inches71 and the error resulting from each filling of a bulb is certainly less than #ae cubic millimeters 7#j4jjji cubic inches74 ,the contents are emptied into a bell by lowering the bulb into the water and opening the cock4 ,if seven bulbfuls of air be mixed with one bulbful of gas1 an explosive mixture of #a to #g is produced1 this being the proportion commonly employed for street-gas4 ,for producer-gases the preferred proportion is #a to #a1 oxygen being often added to the air in order to insure complete combustion4 ,the calorimeter1 after having been filled1 is placed in a vessel containing a liter 7#a4geih pints7 of water so that it is completely immersed4 ,a spark is then allowed to pass4 ,the explosion is not accompanied by any noise2 the temperature rises a fixed number of degrees1 so that the quantity of heat liberated can easily be computed4 ,each division of the thermometer is equal to #j4jaejb ,c4 ,the scale reading is minute1 each interval being divided by ten1 so that readings to the #a1ejjth part of a degree can be taken4 ,it should be observed that the mixture generated in the reservoir is saturated with water vapor at the temperature of the reservoir4 ,consequently1 the vapor generated by the explosion must condense in the calorimeter if the final temperature of the calorimeter is the same as that of the water reservoir4 ,if1 on the other hand1 the temperature be slightly different1 a correction must be made2 but the error is negligible for differences in temperature of from #b to #c degrees ,c4 7#c4f to #e4d degrees ,f474 ,this1 however1 is never likely to occur if the operation is conducted under favorable conditions4 ,this apparatus is exceedingly simple and practical4 ,it does not require the manipulation of a pump4 ,the pressure of the mixture is read off on the barometer2 the calorimeter is entirely immersed in the water of the outer vessel1 so that all corrections of doubtful accuracy are obviated4 ,the method requires but a very slight correction for temperature4 ,air1 alone or mingled with oxygen1 or a mixture of air and oxygen1 can be easily tested with4 ,maintenance of ,plants4--,if it should be necessary to retain a consulting engineer to install an engine capable of filling all requirements1 it is also necessary to select a careful attendant in order that the engine may be kept in good condition4 ,it is a rather widespread belief that a gas-engine can be operated without any care or inspection4 ,this belief is all the more prevalent because of the employment of street-gas engines1 which1 by reason of their simplicity of construction and regularity of fuel supply1 often run for several hours1 and even for an entire day1 without any attention whatever4 ,but this negligence1 particularly in the case of engines driven from producers1 is likely to produce disastrous results4 ,although engines of this type do not require constant inspection during operation1 still they require some attention in order that the speed may be kept at a fixed number of revolutions4 ,moreover1 the care of the engine1 the cleaning of the valves and of the various parts which are likely to become dirty1 and the examination and cleaning of pipes1 should be accomplished with great care and at regular intervals4 ,this task should be entrusted only to a man of intelligence4 ,a common workman who knows nothing of the care with which the parts of an engine should be handled is likely to do more harm than good4 ,the factory owner who follows the instructions which have been given in this book will avoid most of the stoppages and the trouble incurred in engine and generator installations1 and may count upon a steadiness of operation comparable with that of a steam-engine4 ,,test ,,of ,a ,,stockport ,,gas-,,engine ,,with ,,dowson ,,pressure ,,gas ,,plant ,made by ,r4 ,mathot at the ,works of the ,union ,electrique ,cie1 ,brussels1 ,june #bg1 #aija ,piston ,diameter3 #ae-a_/b4 ,piston stroke1 #bb4 ,normal number of revolutions1 #baj4 #a4 ,calorific value of the coal #abgej ,b4,t4,u4 #b4 ,nature and origin of fuel3 ,anthracite coal of ,charleroi 7,belgium74 #c4 ,cost of fuel per ton at the mine #e4ej #d4 ,cost of fuel per ton at the plant #f4ci #e4 ,fuel consumption per hour in the generator #df4c lbs4 #f4 ,fuel consumption per hour in the boiler #g lbs4 #g4 ,proportion of ash in the coal #f per cent4 #h4 ,weight of steam at #ff lbs4 generated per hour #db4g lbs4 #i4 ,average brake horse-power #ec ,b4,h4,p4 #aj4 ,fuel consumption for gas per ,b4,h4,p4 per hour #j4hge lbs4 #aa4 ,fuel consumption for steam per ,b4,h4,p4 per hour #j4acc lbs4 #ab4 ,total fuel consumption #a4jjh lbs4 #ac4 ,steam consumption at #ff lbs4 pressure #j4ha lbs4 #ad4 ,gas pressure at the engine #a-c_/h inches #ae4 ,weight of water per ,b4,h4,p4 per hour for cooling the cylinder entering at #fh deg4 ,f4 and leaving at #aje deg4 ,f4 #ea4e lbs4 #af4 ,corresponding heat absorbed in cooling #aigj ,b4,t4,u4 #ag4 ,average initial explosive pressure on piston #cbd lbs4 #ah4 ,average pressure on piston per square inch #gb lbs4 #ai4 ,average indicated horse-power with #he per cent4 misses #ib4e ,i4,h4,p4 #bj4 ,corresponding mechanical efficiency #hd per cent4 #ba4 ,corresponding electric load #ca4iej ,k4,w4 #bb4 ,cost of ,b4,h4,p4 per hour in anthracite #j4jjbi #bc4 ,cost of kilowatt per hour in anthracite #j4jjdh #bd4 ,electric power generated per ,b4,h4,p4 #fjb4h ,w4 #be4 ,thermal efficiency at #ec ,b4,h4,p4 with #he per cent4 explosions #ah4e per cent4 ,,test ,,of ,a #bj ,h4,p4 ,,winterthur ,,engine ,with ,winterthur ,suction-,producer made by ,r4 ,mathot at ,winterthur1 ,june #d and #e1 #aijb ,,data ,,of ,,tests ,,with ,,illuminating ,,gas ,,and ,,with ,,fuel ,,gas ,dimensions of ,winterthur ,engine--,piston diameter3 #aj-c_/h4 ,stroke3 #af-g_/h4 ,compression3 #agg pounds per square inch4 ,regulation3 hit and miss4 ,ignition3 electro-magnetic4 ,fly-wheel3 normal1 with external bearing4 ,lubrication of piston3 with oil-pump4 ,of main bearings1 with rings 7as in dynamos74 ,,full ,,load ,,with ,,street-,,gas #a4 ,number of revolutions per minute #bjj #b4 ,corresponding number of explosions #if per cent4 #c4 ,net load on brake #abj lbs4 #d4 ,corresponding effective power #bb ,b4,h4,p4 #e4 ,mean initial explosive pressure on piston per square inch #dee lbs4 #f4 ,average pressure on piston per square inch #gh lbs4 #g4 ,gas consumption per ,b4,h4,p4 at #bd deg4 ,c4 and #gba mm4 mean pressure #ae4e cubic feet #h4 ,gas consumption per ,b4,h4,p4 reduced to #j deg4 ,c4 and #gfj mm4 mean pressure #ac4e cubic feet ,,half ,,load ,,with ,,street-,,gas #i4 ,number of revolutions per minute #bjd #aj4 ,corresponding number of explosions #fj per cent4 #aa4 ,net load on brake #fj lbs4 #ab4 ,corresponding effective power #aa4f ,b4,h4,p4 #ac4 ,gas consumption per ,b4,h4,p4 per hour at #bd deg4 ,c4 and #gba mm4 mean pressure4 #ba cubic feet #ad4 ,gas consumption per ,b4,h4,p4 per hour at #j deg4 ,c4 and #gfj mm4 mean pressure4 #ah4c cubic feet ,,running ,,with ,,no ,,load ,,with ,,street-,,gas #ae4 ,number of revolutions per minute #bjf #af4 ,corresponding number of explosions #bb per cent4 #ag4 ,total gas consumption per hour at #bd deg4 ,c4 and #gba mm4 mean pressure4 #ajf cubic feet #ah4 ,maximum calorific power of gas per cubic foot #eih ,b4,t4,u4 #ai4 ,thermal efficiency with #if per cent4 explosions #ca per cent4 #bj4 ,mechanical efficiency with #if per cent4 explosions #hb per cent4 #ba4 ,temperature of water at the jacket-inlet #ge degs4 ,f4 #bb4 ,temperature of water at the jacket-outlet #acj degs4 ,f4 #bc4 ,compression per square inch on piston surface #agh lbs4 #bd4 ,pressure after expansion #cg lbs4 ,,test ,,of ,,winterthur ,,plant ,,with ,,producer-,,gas #a4 ,nature of fuel4 ,belgian anthracite1 ,bonne ,esperance et ,batterie2 size1 #c_/d inch4 #b4 ,chemical composition3 ,carbon1 #hf4e per cent42 hydrogen1 #c4e per cent42 oxygen and nitrogen1 #d4fe per cent42 ash1 #e4ce per cent4 #c4 ,calorific value per pound of coal #adbjj ,b4,t4,u4 #d4 ,net calorific value per pound of fuel #aejej ,b4,t4,u4 #e4 ,price of anthracite delivered at the plant #c4ej per ton #f4 ,number of revolutions of engine per minute #bjj #g4 ,corresponding number of explosions #ia per cent4 #h4 ,load on brake #ajf lbs4 #i4 ,corresponding effective horse-power #bj4b ,b4,h4,p4 #aj4 ,fuel consumption at the generator per hour #af4d lbs4 #aa4 ,fuel consumed per ,b4,h4,p4 per hour #j4ha lbs4 #ab4 ,proportion of ash resulting from the tests #f per cent4 #ac4 ,mean initial explosive pressure per square inch #dai4e lbs4 #ad4 ,average pressure on piston per square inch #gb4e lbs4 #ae4 ,indicated horse-power with #ia per cent4 explosions #be4d ,i4,h4,p4 #af4 ,mechanical efficiency #gi per cent4 #ag4 ,thermal efficiency at the producer #bb per cent4 #ah4 ,water consumption per hour in the scrubber #ff gals4 #ai4 ,cost per ,b4,h4,p4 per hour in anthracite #fb gals4 ,,test ,,of ,a #fj ,b4,h4,p4 ,,gas-,,engine1 ,,type ,g #i1 ,,with ,a ,,suction-,,gas ,,plant ,,of ,,the ,,gasmotoren ,,fabrik ,,deutz 7,made at ,cologne1 ,march #ae1 #aijd1 by ,r4 ,mathot47 ,,data ,,of ,,the ,,tests ,diameter of ,piston #af4e4 ,piston ,stroke #ah4i ,,full ,,load #a4 ,average number of revolutions per minute #ahh4ff #b4 ,corresponding effective work #fe4aa ,b4,h4,p4 #c4 ,average compression per square inch #agf lbs4 #d4 ,average initial explosive pressure per square inch #cig lbs4 #e4 ,average final expansion pressure #be lbs4 #f4 ,vacuum at suction #d4d lbs4 #g4 ,average pressure on piston #ha lbs4 #h4 ,corresponding indicated horse-power #gg ,i4,h4,p4 ,,fuel #i4 ,nature of fuel3 ,anthracite coal #j4d to #j4h #aj4 ,origin3 ,coalpit of ,zeihe1 ,morsbach at ,aix-la-,chapelle4 #aa4 ,chemical composition of coal3 ,carbon #hc4bb ,hydrogen #c4ca ,nitrogen and ,oxygen #c4ja ,sulphur #j4dd ,ash #g4cc ,water #b4fi #ab4 ,calorific value4 #acfej ,b4,t4,u4 ,,gas #ac4 ,chemical composition of gas3 ,carbonic acid #f4fj ,oxygen #j4cj ,hydrogen #ah4ij ,methane #j4eg ,carbon monoxide #bd4cj ,nitrogen #di4cc #ad4 ,calorific value of gas1 combination water1 at #ei deg4 ,f4 constant volume reduced to #cb deg4 ,f4 and atmospheric pressure #adj ,b4,t4,u4 ,,temperatures ,engine #ae4 ,cooling water at the inlet of the cylinder-head #ee4d deg4 ,f4 ,temperature at the outlet #aji4e deg4 ,f4 #af4 ,temperature at outlet of cylinder #abg4e deg4 ,f4 ,gas-,generator #ag4 ,temperature of water in the vaporizer #aeh4c deg4 ,f4 ,,efficiencies ,,and ,,consumption #ah4 ,mechanical efficiency #hd4f #ai4 ,gross consumption of coal per ,b4,h4,p4 per hour #j4hf lbs #bj4 ,thermal efficiency in proportion to the effective work and the gross consumption of coal in the gas-generator #bd4c ,,half ,,load ,,work #a4 ,average number of revolutions per minute #aie4e #b4 ,corresponding effective work #cc4he ,b4,h4,p4 #c4 ,corresponding average compression #abe lbs4 #d4 ,average initial explosive pressure #beh lbs4 #e4 ,average final expansion #ah lbs4 #f4 ,vacuum at suction #f4h lbs4 #g4 ,average mean pressure on piston #df4b lbs4 #h4 ,corresponding indicated power #de4 ,i4,h4,p4 #i4 ,speed variation between full and half load #c4e ,,consumption #aj4 ,gross consumption of coal per ,b4,h4,p4 per hour #a4aee lbs4 ,,running ,,with ,,no ,,load #a4 ,average number of revolutions per minute #aii #b4 ,minimum corresponding compression #ie4ee lbs4 #c4 ,average initial explosive pressure #bbj lbs4 #d4 ,average final expansion #j lbs4 #e4 ,vacuum at suction #h4h lbs4 #f4 ,average pressure on piston #aa4b lbs4 #g4 ,corresponding indicated horse-power4 #aa ,i4,h4,p4 #h4 ,speed variation between full load and no load #e4b ,,test ,,of ,a ,,gas ,,plant ,,of ,a ,,four-,,cycle ,,double-,,acting ,,engine ,,of #bjj ,h4,p4 ,,and ,a ,,suction-,,producer ,,in ,,the ,,works ,,of ,,the ,,gasmotoren ,,fabrik ,,deutz1 ,,cologne ,march #ad and #ae1 #aijd1 by ,messrs4 ,a4 ,witz1 ,r4 ,mathot1 and de ,herbais ,,data ,,of ,,the ,,tests ,piston ,diameter3 #ba-a_/d4 ,stroke3 #bg-i_/af4 ,diameter of ,piston-,rods3 front1 #d-c_/d2 rear1 #d-e_/af ,,engine ,full ,load ,tests #a4 ,average number of revolutions per minute #aea4bi and #aej4bj #b4 ,corresponding effective load #bad4bb ,b4,h4,p4 and #bbb4hc ,b4,h4,p4 #c4 ,duration of the tests #c hours and #aj hours #d4 ,average temperature of water after cooling the piston #aag4e deg4 ,f4 #e4 ,average temperature of water after cooling the cylinder and valve-seats #ace deg4 ,f4 #f4 ,water consumption per hour for cooling the piston #ci gal4 ,,producer #g4 ,nature and ,origin of ,fuel3 ,anthracite coal ,bonne-,esperance et ,batterie ,herstal1 ,belgium4 #h4 ,calorific value of fuel #adfej ,b4,t4,u4 #i4 ,consumption of fuel per hour 7plus #ec lbs4 on the night of the #adth for keeping the generator fired during #ad hours1 the engine being stopped7 #aii lbs4-#afj lbs4 #aj4 ,water consumption per hour in the vaporiser #ad4b gals4 #aa4 ,water consumption per hour in the scrubbers #cah gals4 #ab4 ,average temperature of gas at the outlet of the generator #eeh deg4 ,f4 #ac4 ,average temperature of gas at the outlet of the scrubbers #fb4e deg4 ,f4 ,,efficiencies #ad4 ,gross consumption of coal per ,b4,h4,p4 per hour #j4ibg lbs4-#j4gbj lbs4 #ae4 ,consumption of coal per ,b4,h4,p4 after deduction of the water #j4ijg lbs4-#j4gje lbs4 #af4 ,thermal efficiency relating to the effective ,h4,p4 and to the dry coal consumed in the generator #ai-bd4d #ag4 ,water consumption per ,b4,h4,p4 hour3 ,for the cylinder1 stuffing-boxes and valve-seat jackets #d4fe gals4 ,for the piston and piston-rods #a4ge gals4 ,for the vaporizer #j4jfee gals4 ,for washing the gas in the scrubbers #a4db gals4 #ah4 ,water converted in steam per lb4 consumed in the generator #j4aic gals4 ,,index ,a ,adjustment of gas-engine1 #abf ,adjustment of moving parts1 imperfect1 #adf ,admission-valve1 binding of1 #aeb ,admission1 variable1 #ee1 #ef ,air-blast1 #ahj ,air-chest1 #hb ,air1 displacement of1 #ib ,air1 exclusion of1 in producers1 #bjg ,air1 filtration of1 #hb ,air-heater1 ,winterthur1 #bcf ,air-heaters1 #bch ,air-pipe1 #hb ,air-pipe1 location of1 #hc ,air-pump1 #bff ,air1 regulation of supply1 #hb ,air suction1 #ha ,air suction1 resistance to1 #hb ,air supply of producer1 #bbe ,air-valve1 control by engine1 #be ,air vibration1 #ib ,alcohol as engine fuel1 #bfd ,anthracite1 consumption of1 in producers1 #bjj ,anthracite in producers1 #aij1 #bja ,anti-pulsators1 #gg ,anti-pulsators1 disconnection of1 in stopping engine1 #acb ,anti-pulsators1 precautions to be taken with1 #gi ,anti-vibratory substances1 #hi ,ash-pit1 #bad1 #bag ,ash-pit1 ,bollinckx1 #bbj ,ash-pit1 cleaning of1 #bfa ,ash-pit1 ,deutz1 #bbj ,ash-pit1 door of1 #bbj ,ash-pit1 ,wiedenfeld1 #bbj ,asphyxiation1 #afi ,atomizer of oil-engines1 #bfe ,b ,back firing1 #hb1 #aca ,back pressure to exhaust1 #aea ,bags1 arrangement of1 #hj ,bags1 capacity of1 #gi ,bags1 precautions to be taken with1 #gi ,bags1 rubber1 #gg ,bark as producer fuel1 #aic ,batteries for ignition1 #ca ,bearings1 adjustability of1 #e ,bearings1 adjustment of1 #dd ,bearings1 care of1 #abc ,bearings1 lubrication of1 #aag ,bearings1 material of1 #ea ,bearings of fly-wheels1 #ib ,bearings1 overheated1 #adf ,bearings1 over-lubricated1 #aej ,bearings1 position of1 #dd ,bell1 gas-holder1 #ahg ,bell1 ,pintsch1 #bdh ,bell1 volume of1 #ahg ,belts1 prevention of adhesion by oil1 #abj ,benier1 ,e41 #aii ,benzin as engine fuel1 #bfd ,binding1 #adg ,blast in producers1 #ahj1 #aic1 #bbe ,blower1 ,koerting1 #aha ,blower1 ,root1 #ahb1 #ahh ,blowers for producers1 #aha ,blowing-generators1 #afi ,bolts of foundation1 #ia ,bomb1 ,witz1 #bhd1 #bib ,boughs for coolers1 #ajh ,box1 charging1 #bba ,box1 double closure for charging1 #bbb ,box1 removable charging1 #bbe ,brake tests1 #bhd ,branch pipes1 minimum diameter of1 #ha ,bricks for foundation1 #ia ,brushes1 lifting of1 when dynamo-engine is stopped1 #acb ,brush1 purifying1 #bej ,burner of hot tube1 how ignited1 #abh ,burner1 regulation of fixed1 #add ,bushings1 care of1 #abc ,bushings1 fusion of1 #adg ,bushings 7see also ,bearings7 ,c ,calorimeter1 ,witz1 #bib ,calorimeters1 #bhd1 #bij ,cam1 half-compression1 #acj1 #acb ,cam1 relief1 #acj ,cams1 #ea ,caps of valve-chests1 #abd ,carbureter1 #bff ,care during operation of engine1 #aca ,casing1 independence of frame1 #db ,charging a producer1 #bba ,charging the generator1 #bei ,chest for exhaust1 #hc ,circulation of water1 #ih1 #abe ,circulation of water1 how effected1 #ajb ,circulation of water in tanks1 #aje ,circulation of water1 regulation of1 #ajg ,cleaning of producer1 #bfa ,cleanliness1 necessity of1 #aba ,cleanliness of producers1 #agi ,closures for charging-boxes1 #bbc ,coal in producers1 #bja ,coal in producers1 bituminous1 #aie ,coal1 ,pennsylvania1 #bjc ,coal 7see also ,anthracite7 ,coal1 ,welsh1 #bjc ,cock1 ,deutz1 #bbd ,cock1 ,pierson1 #bbd ,cock for charging-box1 #bbc1 #bbd ,coke in producers1 #bja ,coke in washers1 #bdb ,combustion-generators1 #aic ,combustion1 inverted1 #aie ,compression1 determination of1 #bgc ,compression1 faulty1 #acd ,compression1 high1 #aed ,compression in ,banki engine1 #bfd ,compression in ,diesel engine1 #bfd ,compression1 losses in1 #adc ,compression period1 #ba ,compression1 relation to power developed1 #abb ,compressors for producers1 #ahb ,connecting-rod bearings1 #de ,connecting-rod bearings1 rational design of1 #de ,connecting-rod1 lubrication of1 #aac1 #aae ,consulting engineer1 advisability of retaining1 #bhb ,consumption at half load and full load1 #fb ,consumption at various loads1 #fb ,consumption in double or triple acting engines1 #fb ,consumption of gas1 #agc ,consumption of gas in burner1 #cj ,consumption of suction-producers1 #bjj ,consumption per effective horse-power1 #fb ,cooler for gas1 #aii ,cooler1 for producer1 #bdj ,coolers1 #ajg ,coolers1 size of1 #aji ,cooling of cylinder1 #ih1 #ajj1 #aef ,cooling of producer-gas engines1 #bjc ,cooling1 thermo-siphon1 #ajj ,cost of oil and volatile hydrocarbon engines1 #bfh ,crank-pin1 tensile strength of1 #ea ,crank-shaft1 #ej1 #ea ,crank-shaft bearings1 #dd ,crank-shaft bearings1 design of1 #df ,crank-shaft1 effect of premature explosion on1 #cj ,crank-shaft lubrication1 #aag ,crank-shaft1 material of1 #ej ,crosshead1 care of1 #abc ,cycle1 analysis of1 #bgf ,cylinder1 arrangement of1 #da ,cylinder1 cleaning of1 #abb ,cylinder1 cooling of1 #aef ,cylinder1 evacuation of1 #hc1 #aca ,cylinder1 gravel in1 #acg ,cylinder1 grinding of1 #db ,cylinder1 incandescent particles in1 #adb ,cylinder1 independence of casing1 ,compression in1 #db ,cylinder-jacket 7see ,water-jacket7 ,cylinder lubrication1 #aab ,cylinder-oil1 #aab1 #adi ,cylinder1 overhang in horizontal engines1 #db ,cylinder1 overheating of1 #adh ,cylinder1 presence of water in1 #acf ,cylinder-shell1 #da ,cylinder1 smoke from1 #adi ,cylinder1 temperature during operation of engine1 #acb ,cylinder1 thrust of1 #dc ,cylinder1 tightness of1 #abb ,d ,damper1 ,pintsch1 #bbd ,dampers1 #bbc ,detonations1 untimely1 #ada ,distributing mechanism1 derangement of1 #aeb ,drain-cock in gas-pipes1 #gj1 #ge ,drain-cocks1 testing of1 #bef ,drier for producer-gas1 #bdh ,dust-collector1 #bci ,dust-collector1 ,benz1 #bci ,dust-collector1 ,bollinckx1 #bci ,dust-collector1 ,pintsch1 #bci ,dust-collector1 ,wiedenfeld1 #bci ,dynamo1 lifting brushes from1 in stopping engine1 #acb ,e ,ebelmen principle1 #aie ,engine1 ,banki1 #bfd ,engine1 ,diesel1 #bfd ,engine1 producer-gas and steam1 compared1 #bjc ,engine1 selection of1 #bgi ,engine1 starting a producer-gas1 #beh ,engineer1 duty of a consulting1 #bha ,engines1 governing oil1 #bfe ,engines1 oil1 #bfd1 #bfe ,engines1 producer-gas1 #aec ,engines1 producer-gas1 temperature of1 #aeg ,engines1 specifications of1 #bha ,engines1 speed of oil1 #bfd ,engines1 tests of1 #bfh ,engines1 volatile hydrocarbon1 #bfd1 #bfg ,engines1 writers on oil1 #bff ,escape-pipes1 #bbh ,essences1 #bfd ,exhaust1 #hc ,exhaust1 back pressure to1 #aea ,exhaust1 determination of resistance to1 #bgd ,exhaust into sewer or chimney1 #he ,exhaust1 noises of1 #id1 #ada ,exhaust period1 #bb ,exhaust1 water in1 #acf ,exhausters1 #ahc ,exhaust-chest1 #hc ,exhaust-muffler1 #hf1 #id ,exhaust-pipe1 #hc1 #he ,exhaust-pipe1 design of1 #if1 #ig ,exhaust-pipe1 joints for1 #he ,exhaust-pipe1 oil in1 #aea ,exhaust-valve1 binding of1 #aeb ,exhaust-valve1 cooling of1 #be ,expansion-boxes1 #ie ,expansion period1 #bb ,expert1 necessity of an1 #bhb1 #bhc ,explosion1 spontaneous1 #adj ,explosion-engines 7see ,gas-engines7 ,explosion period1 #bb ,explosion-recorder1 analysis of inertia of1 #bgg ,explosion-recorder for industrial engines1 #bhe ,explosion-recorder1 the continuous1 #bfi ,explosions1 comparison of average force of1 #bge ,explosion-records1 #bhh ,explosions1 retarded1 #adc ,f ,fans for producers1 #aha ,feeder1 ,winterthur1 #bcf ,feed-hopper1 #bbd ,fire-box1 door of1 #bba ,flues1 escape1 #bbh ,fly-wheel1 oil on1 #abj ,fly-wheel1 starting the1 #aca ,fly-wheels1 #df ,fly-wheels as pulleys1 #df ,fly-wheels1 balancing of1 #df ,fly-wheels1 curved spoke1 how mounted1 #di ,fly-wheels1 fastening of1 #df ,fly-wheels1 proper mounting of1 #df ,fly-wheels1 rim of1 #df ,fly-wheels1 single1 #dh1 #ib ,fly-wheels1 single1 for dynamo-engines1 #df ,fly-wheels1 straight and curved spoke1 #di ,fly-wheels with hit-and-miss system1 #ej ,foundation1 #dd1 #hg ,foundation1 design of1 #hh1 #hi ,foundation1 excavation for1 #hh ,foundation1 insulation of1 #hi1 #ij ,foundation of dynamo-engine1 #ia ,frame1 #dc ,frame1 method of securing1 to foundation1 #dd ,fuel of producers1 #agh1 #ahg1 #bed ,fuel1 qualities of1 #bja ,fuel 7see also ,lignite1 ,peat1 ,sawdust1 ,wood1 ,coal1 etc47 ,fuel1 size of1 #bja ,fuel1 smoke-producing1 #bed ,g ,gas1 ascertaining purity of1 #abh ,gas1 blast-furnace1 #aec ,gas1 calorific value of1 #bhd ,gas1 calorific value of producer1 #bjj ,gas1 coke-oven1 #aec ,gas consumption1 #agc ,gas consumption of burner1 #cj ,gas1 effect of quality1 #aeb ,gas-engine1 balancing of1 #df ,gas-engine1 care during operation1 #aca ,gas-engine1 cost of installation1 #ai ,gas-engine1 cost of operation1 #ai ,gas-engine1 difficulties in starting1 #acd ,gas-engine1 how to start a1 #abh ,gas-engine1 how to stop a1 #acb ,gas-engine1 installation of a1 #fh ,gas-engine1 location of a1 #fh ,gas-engine1 selection of a1 #ba ,gas-engine1 simplicity of installation1 #ag ,gas-engine1 the four-cycle1 #ba ,gas-engines1 adjustment of1 #abf ,gas-engines1 care of1 #aba ,gas-engines1 ,steam-,hammer1 #eg ,gas-engines1 temperature of1 #aeh ,gas-engines1 tests of1 #bhc ,gas-engines1 vertical1 #ef ,gas-engines1 writers on1 #fh ,gas1 fuel1 #aec ,gas-holder1 #ahf1 #ahi ,gas-holders1 #bdg ,gas-holder1 combined with washer or scrubber1 #ahf ,gas1 illuminating 7see ,street-gas7 ,gas1 impurities of1 #agb ,gas1 ,mond1 #aec1 #afg ,gasometer 7see ,gas-holder7 ,gas1 producer 7see ,producer-gas7 ,gas production1 #agc ,gas1 purification of wood1 #aie ,gas supply1 necessity of coolness1 #fi ,gas-valve1 necessity of independent operation of1 #bg ,gas1 water1 #aec1 #afi ,gas1 wood1 #aec1 #afh ,gases1 analysis of1 #bij ,generator 7see also ,producer7 ,generator1 ,benz1 #bjg ,generator1 ,bollinckx1 #bjg ,generator1 care of1 #bei ,generator1 charging the1 #bei ,generator1 construction of1 #agg1 #bjg ,generator1 dimensions of1 #beb ,generator1 ,dowson1 #agg ,generator1 firing the1 #bje1 #bef ,generator1 hot operation of1 #beb ,generator of suction producer1 #bje ,generator1 operation of1 #bea ,generator1 ,pierson1 #bae ,generator1 ,pintsch1 #bjg ,generator1 ,taylor1 #bjg ,generator1 ,wiedenfeld1 #bjg ,generator1 ,winterthur1 #bjg ,generator with internal vaporizer1 #bjf ,generators1 blowing1 #afi ,generators1 pressure1 #afi1 #agg ,governor1 ball1 #eb1 #ec ,governor1 care during operation1 #aca ,governor1 hit-and-miss1 #eb1 #ed ,governor1 inertia1 #ec ,governor1 sensitiveness of1 #eb ,governors1 #ec ,governors1 adjustment of1 #abd ,governors1 care of1 #abc ,governors1 centrifugal1 #ef ,governors1 centrifugal1 with hit-and-miss regulation1 #ee ,governors for oil-engines1 #bfe ,governors for producer-gas engines1 #afa ,governors1 hit-and-miss1 #ed ,governors1 variable admission1 #ef ,grate1 ,benier's1 #baf ,grate of generator-lining1 #bad ,grate1 ,kiderlen1 #baf ,grate1 ,pintsch1 #baf ,grate1 ,wiedenfeld1 #baf ,h ,heater1 air1 #bch ,hit-and-miss regulation 7see ,governors7 ,holders1 gas1 #bdg ,hopper1 ,bollinckx1 #bbe ,hopper1 ,deutz1 #bbe ,hopper for generator1 #bbd ,hopper1 removable feed1 #bbe ,hopper1 ,taylor1 #bbe ,hopper1 ,wiedenfeld1 #bbe ,hopper1 ,winterthur1 #bbe ,horse-power1 definition of1 #fj ,horse-power1 determination of1 #fa ,horse-power 7see also ,power7 ,hot tubes 7see ,tubes7 ,hydrocarbons1 volatile1 for engine fuel1 #bfd ,i ,ignition1 #bg1 #abb ,ignition1 adjustment of1 #add ,ignition by battery and coil1 #ca ,ignition by magneto1 #cc ,ignition1 curing defects of electric1 #ade ,ignition1 defective1 #aeb ,ignition1 disadvantages of belated1 #bh ,ignition1 disadvantages of premature1 #bh ,ignition1 effect of lost motion1 #adf ,ignition1 effect of mixture composition on1 #bh ,ignition1 effect of temperature of flame on1 #bh ,ignition1 effect of water on1 #acf ,ignition1 electric1 #cj1 #aci ,ignition1 electric1 regulation of1 #ade ,ignition1 faulty1 #adc ,ignition for high-pressure engines1 #ce ,ignition1 hot-tube1 #aei ,ignition1 imperfect1 #acg ,ignition1 objections to electric1 #ca ,ignition of producer-gas1 #afj ,ignition1 premature1 #aci1 #adb ,ignition1 premature1 in high-pressure engines1 #aeh ,ignition1 prevention of1 by faulty compression1 #acd ,ignition1 proper timing of1 #bg ,ignition1 spontaneous1 #adj1 #aei ,ignition1 tests prior to starting engine1 #abi ,ignition-tubes 7see ,tubes7 ,incrustation of water-jacket1 #ih1 #adh ,incrustation1 prevention of1 #ajg ,incrustations1 #bee ,indicators1 #bhe ,indicator-records1 #abg ,induction-coil1 #cb ,installation1 laws governing gas-engine1 #hf ,j ,joints1 #abe ,joints1 care of1 #abd ,l ,laming mass1 #bdf ,laws governing gas-engines1 #hf ,leakage of pipes1 #fi ,lift-valve for charging-box1 #bbc ,lignite in producers1 #ahh ,lining1 refractory1 #baa ,lining1 support for generator1 #bad ,loads1 consumption at half and full1 #fb ,location of engine1 #fh ,lubricate 7see ,oils7 ,lubricating-pumps1 #aae ,lubrication1 #aaa1 #aba ,lubrication1 difficulties entailed by1 #aai ,lubrication1 faulty1 #adi ,lubrication of crank-shaft1 #aag ,lubrication of high-power engine1 #aaf ,lubrication of valve-stem1 #aai ,lubricator1 cotton-waste1 #aag ,lubricators1 automatic1 #aac ,lubricators1 disconnection of1 when stopping engine1 #acb ,lubricators1 examination of1 before starting1 #abi ,lubricators1 feed of1 #aba ,lubricators1 revolving-ring1 #aah ,lubricators1 sight-feed1 #aah ,lubricators1 types of1 #aac ,m ,magneto1 adaptability for producer-gas1 #ce ,magneto1 control of1 #ch ,magneto1 efficiency of1 #cd ,magneto-igniter1 construction of1 #ce ,magneto ignition1 #cc ,magneto ignition1 precautions to be taken1 #cd ,magneto1 inspection of1 before starting engine1 #abi ,magneto1 mechanical control of1 #cc ,magneto1 operation of1 #cc ,magneto1 regulation of1 #cg ,maintenance of plants1 #bie ,manograph1 #bfi ,mass1 ,laming1 #bdf ,meters1 capacity of1 #gj ,meters1 dry1 #gb ,meters1 evaporation in wet1 #gj ,meters1 falsification of records1 #gj ,meters1 inclination of1 #ga ,meters1 size of1 #ga ,misfire1 #acg ,mixture1 effect of high compression in1 #aee ,mixture1 effect of high pressure on1 #aef ,mixture1 governing by varying the1 #afa-afd ,mixture1 poorness of1 #adc ,mixture1 pressure of1 #bf ,mixture-valve1 necessity of independence of operation of1 #bg ,mortar for foundation1 #hg ,motion1 lost1 #adf ,muffler for exhaust1 #hf1 #id ,n ,naphthalene in gas-pipes1 #gj ,noises1 cause of1 #ib ,noises of exhaust1 #id ,o ,oilers 7see ,lubricators7 ,oiling 7see ,lubrication7 ,oil1 addition of sulphur to1 #adg ,oil1 cylinder1 #adi ,oil-engines1 #bfd1 #bfe ,oil-engines1 governing1 #bfe ,oil-engines1 speed of1 #bfd ,oil-engines1 writers on1 #bff ,oil for engine fuel1 #bfd ,oil1 freezing of1 #aej ,oil-guard for fly-wheel1 #abj ,oil-lamp1 #bff ,oil1 prevention of spreading on fly-wheel1 #abj ,oil-pumps1 #aae1 #bbf ,oil1 quality of1 #aej ,oil1 splashing of1 #aai ,oil-tank1 #bff ,oils1 how tested1 #aab ,oils1 mineral for lubrication1 #aab ,oils1 purification of1 #aac ,oils1 quality of1 #aab ,oils1 requisites of1 #aab ,operation1 steadiness of1 #eb ,otto cycle1 #ba ,overheating1 #aeb ,overheating1 prevention of1 #adg ,p ,pacini treatment1 #aga ,peat in producers1 #ahh ,perturbations1 #acd ,petrol 7see ,oil7 ,pipe-hangers1 #hf ,pipes1 #fi ,pipes1 cross-section of1 #gj ,pipes1 disposition of1 #gg ,pipes1 escape1 #bbh ,pipes1 exposure to cold1 #fi ,pipes for exhaust1 #hc ,pipes for producer-gas1 #bdi ,pipes for water-tanks1 #ajb1 #ajc1 #aje ,pipes1 hanging of1 #hf ,pipes1 insulation from foundations and walls1 #id ,pipes1 leakage of1 #fi ,pipes1 minimum diameter of branch1 #ha ,pipes1 proper size of1 #gj ,piston1 #ci1 #abb ,piston1 avoidance of insertions or projections1 #ci ,piston1 cleaning of1 #ada ,piston1 curved faces inadvisable1 #ci ,piston1 direct connection with crank-shaft1 #dc ,piston1 finish of1 #da ,piston1 importance of1 #aaa ,piston1 leakage of1 #acf ,piston1 overheating of1 #adh ,piston1 position of1 in starting1 #acj ,piston1 rear face of1 #ci ,piston-pin1 construction of bearing at1 #dj ,piston-pin1 location of1 #da ,piston-pin1 locking of1 #dj ,piston-pin1 lubrication of1 #aac ,piston-pin1 material of1 #dj1 #ea ,piston-pin1 strength of1 #dj ,piston-rings1 fouling of1 #adi ,piston-rings1 material of1 #da ,piston-rings1 number of1 #da ,piston-rod1 effect of premature explosion on1 #cj ,piston-wear1 #dj ,poisoning1 carbon monoxide1 #agj ,porcelain of spark-plug1 #cb ,power1 definition of1 #fj ,power1 measuring engine1 #bhe ,power1 ,nominal1 #fa ,precautions to be taken in starting1 #abh ,pressure1 back1 to exhaust1 #aea ,pressure-generators1 #afi1 #agg ,pressure in producer-gas engines1 #afj ,pressure-lubricators1 #aad ,pressure-producers1 #agd ,pressure-regulator1 bell as1 #ahg ,pressure-regulators1 #gg ,pressure-regulators1 their construction1 #gh ,pressures1 high1 in producer-gas engines1 #aed ,preheaters1 #bbi ,producer1 assembling1 #bec ,producer1 ,benier1 #baf ,producer1 ,benz1 #bbh1 #bci1 #bdj ,producer1 ,bollinckx1 #bjf1 #bbj1 #bbe1 #bbh1 #bcd1 #bci ,producer1 ,chavanon1 #bbi ,producer1 cleaning of1 #bfa ,producer1 ,dawson1 #agd ,producer1 ,deschamps1 #aih ,producer1 ,deutz1 #bjf1 #bbj1 #bbd1 #bbe1 #bbh1 #bbi1 #bdj ,producer1 ,deutz1 #bca1 #bcb ,producer1 ,deutz lignite1 #ahh ,producer1 ,duff1 #aie ,producer1 ,fange-,chavanon1 #aih ,producer1 ,fichet-,heurty1 #bdj1 #bde ,producer1 ,gardie1 #ahc ,producer-gas1 #aec ,producer-gas1 #afe ,producer-gas as a furnace fuel1 #agg ,producer-gas1 calorific value of1 #bjj ,producer-gas1 composition of1 #aff ,producer-gas plants1 tests of1 #big ,producer-gas1 writers on1 #aed ,producer1 general arrangement of suction1 #bjd ,producer1 ,goebels1 #bjf ,producer1 ,hille1 #bjf1 #bci ,producer1 ,kiderlen1 #bjf ,producer1 ,kiderlen1 #baf ,producer1 ,koerting1 #bcb ,producer1 ,lencauchez1 #bab1 #bad ,producer1 ,phoenix1 #bag ,producer1 ,pierson1 #bbd1 #bbi ,producer1 ,pintsch1 #bjf1 #baf1 #bbd1 #bca1 #bcb1 #bci1 #bde1 #bdh ,producer1 ,riche1 #afh1 #aij1 #aic1 #aie1 #baf ,producer 7see also ,generator7 ,producer1 stoppage of1 #bfa ,producer1 ,taylor1 #bjf1 #bad1 #bbe1 #bca1 #bcb ,producer1 test by smoke1 #bed ,producer1 test of ,deutz1 #bih ,producer1 test of ,dowson1 #bif ,producer1 tests of ,winterthur1 #big ,producer1 ,thwaite1 #aie ,producer1 ,wiedenfeld1 #bjf1 #baf1 #bbj1 #bbe1 #bcd1 #bci ,producer1 ,winterthur1 #bbe1 #bbh1 #bcf ,producers1 advantages of suction1 #aii ,producers1 combustion1 #aic ,producers1 conditions of perfect operation1 #bea ,producers1 consumption of suction1 #bjj ,producers1 distilling1 #aij ,producers1 efficiency of1 #bja ,producers1 efficiency of lignite1 #aij ,producers1 efficiency of wood1 #aid ,producers1 lignite1 #ahh ,producers1 maintenance of1 #bed ,producers1 peat1 #ahh ,producers1 pressure1 #agd ,producers1 self-reducing1 #aic ,producers1 specifications of1 #bha ,producers1 suction1 #aii ,producers1 suction 7see also ,suction-producers7 ,producers1 tests of1 #big ,producers with external vaporizers1 #bjf ,production of gas1 #agc ,pulley1 disconnection of1 in stopping engine1 #acb ,pump1 circulating with by-pass1 #ajf ,purifier1 fiber1 #ahe ,purifier1 ,fichet-,heurtey1 #bde ,purifier1 material for1 #bde ,purifier1 moss1 #ahe ,purifier1 ,pintsch1 #bde ,purifier1 sawdust1 #ahe ,purifiers for gas1 #ahd ,purifiers for producer-gas1 #bdd ,r ,recorder1 analysis of inertia of explosion1 #bgg ,recorder1 explosion1 for industrial engines1 #bhe ,recorder1 the continuous explosion1 #bfi ,records of engines1 #bhd ,records of explosions1 #bhh ,records1 indicator1 #abg ,regrinding of valves1 #abb ,regularity1 cyclic1 #dh1 #ec ,remagnetization of magnetos1 #cc ,resuscitation after asphyxiation1 #aga ,retort1 cleaning of1 #bbe ,retort of producer1 #aij ,retort1 support1 #bad ,revolutions1 variations in number of1 #eb ,rollers1 #ea ,running1 steadiness of1 #eb ,s ,sand for foundation1 #hg ,sawdust in producers1 #aic ,scavenging1 #adb1 #aee ,scrubber1 #ahi1 #aii ,scrubber1 combined with gas-holder1 #ahf ,scrubber for producer-gas1 #bdj ,scrubber1 size of1 #bec ,selection of gas-engine1 #ba ,shavings in producers1 #aic ,slide-valve for charging-box1 #bbc ,slide-valve1 its disadvantages1 #bc ,sluice-valves1 #aja ,smoke from cylinder1 #adi ,spark-plug1 #cb ,specifications of engines1 #bha ,specifications of producers1 #bha ,speed1 how to increase1 #abd ,speed of oil-engines1 #bfd ,speed of volatile hydrocarbon engines1 #bfd ,speed1 variation of1 with load1 #eb ,spokes of fly-wheels1 #di ,spring for valves 7see ,valves7 ,springs1 selection of1 for explosion-recorder1 #bgg ,starter1 ,tangye1 #fe ,starting an engine1 #abh ,starting1 automatic1 #fc1 #acj ,starting by compressed air1 #fd ,starting by hand1 #fc ,starting by hand-pumps1 #fd ,starting1 difficulties in1 #acd ,starting1 how accomplished1 #ff ,starting of producer-gas engine1 #beh ,steadiness1 #eb ,steam-engine1 cost of installation1 #ai ,steam-engine1 cost of operation1 #ai ,stoppage of producer1 #bfa ,stopping the engine1 #acb ,stops1 sudden1 #aea ,straw in producers1 #aic1 #bed ,street-gas1 #afe ,suction1 determination of resistance to1 #bgd ,suction1 noises caused by1 #ada ,suction of air1 #ha ,suction period1 #ba ,suction-producer1 general arrangement of1 #bjd ,suction-producers1 #aii ,suction-producers1 advantages of1 #aii ,suction-producers1 efficiency of1 #bja ,suction-valve1 leakage of1 #adb ,super-heater1 ,winterthur1 #bcf ,sylvester treatment1 #aga ,t ,tanks1 connection of1 #aje ,tanks1 design of1 #ajc ,tanks1 location of1 #ajb ,tanks for water-jacket1 how mounted1 #aja ,tar in producer-plants1 #bjj ,tar1 removal of1 #bej ,tar 7see also ,scrubber1 ,purifier1 etc47 ,taylor1 ,a41 #aii ,terminals of magneto apparatus1 #cd ,tests of gas-engine plants1 #bhc ,tests of high-speed engines1 #bfh ,tests of producer-gas engines1 #big ,thrust-bearings1 #ea ,tongue1 traction of1 in asphyxiation cases1 #agb ,tower1 washer1 #bdd ,town-gas 7see ,street-gas7 ,tree branches for coolers1 #ajg ,trepidations1 #ib ,tube1 gas-supply pipe of incandescent1 #gg ,tube1 incandescent1 #bg ,tube1 incandescent1 adjustment of1 #add ,tube1 incandescent1 breakage of1 #acg ,tube1 incandescent1 danger of breaking1 #aca ,tube1 incandescent1 how started1 #abh ,tube1 incandescent1 leakage of1 #ach ,tubes as vaporizers1 #bca ,tubes1 incandescent1 #bh1 #aei ,tubes1 incandescent1 valved1 #bi ,tubes1 use of special valves with incandescent1 #bi ,tubes1 valveless ignition1 #bh ,v ,valve-chests1 #abd ,valve mechanism1 slide1 #bc ,valve-regrinding1 #abb1 #ace ,valve-stem lubrication1 #aai ,valves1 #abb ,valves1 accessibility of1 #be ,valves1 cooling of1 #be ,valves1 cooling of1 in high-pressure engines1 #aef ,valves1 defective operation of1 #ace ,valves1 free1 #bg ,valves1 mechanical control of1 #bg ,valves1 modern1 #bd ,valves1 necessity of cleanliness1 #be ,valves1 regulation of1 before starting1 #abi ,valves1 requisites of1 #be ,valves1 retardation in action of1 #adf ,vaporizer1 ,bollinckx1 #bcd ,vaporizer1 ,chavanon1 #bbi1 #bcd ,vaporizer1 ,deutz1 #bca1 #bcb1 #bbi1 #bbe ,vaporizer1 ,field1 #bcc ,vaporizer1 internal1 #bjf ,vaporizer1 ,koerting1 #bcb ,vaporizer1 maintenance of1 #bee ,vaporizer1 operation of1 #bcd ,vaporizer1 ,pierson1 #bbi ,vaporizer1 ,pintsch1 #bca1 #bcb ,vaporizer-preheaters1 #bbi ,vaporizer1 size of1 #bec ,vaporizer1 ,taylor1 #bca1 #bcb ,vaporizer1 ,wiedenfeld1 #bbe1 #bcd ,vaporizers1 external1 #bjf1 #bcj ,vaporizers1 internal1 #bbi ,vaporizers1 partition1 #bcd ,vaporizers1 regulation of1 #bcf ,vaporizers1 tubular1 #bca ,ventilation in engine-room1 #fi ,vibration1 #hi ,vibration of air1 #ib ,vibration1 prevention of1 #hi1 #ij ,w ,water circulation1 #ih1 #ajg1 #abe ,water circulation by pump1 #ajg ,water circulation1 care during operation1 #acb ,water circulation1 how effected1 #ajb ,water circulation1 prevention of freezing1 #acc ,water-coolers1 #ajf ,water-coolers1 size of1 #aji ,water for circulation1 #ii ,water for producer-gas engines1 #bjc ,water-gas1 #aec1 #afg ,water in cylinder1 #acf ,water in exhaust1 #acf ,water-jacket1 #da1 #ih1 #abe1 #aeg ,water-jacket1 incrustation of1 #adh ,water-jacket1 outlet of1 #ih ,water-jacket1 prevention of incrustation1 #ajg ,water-pipe1 #ajb ,water1 purification of1 for circulation1 #ih ,water1 running1 for jacket1 #ih ,water-tanks1 #aja ,water-tanks1 connection of1 #ajc1 #aje ,water-tanks1 design of1 #ajc ,water-tanks1 location of1 #ajb ,washer1 ,benz1 #bdj ,washer1 combined with gas-holder1 #ahf ,washer1 ,deutz1 #bdj ,washer1 ,fichet-,heurtey1 #bdj ,washer for gas1 #aii ,washer for producer-gas1 #bdj ,washer1 maintenance of1 #bef ,washer1 material employed in1 #bdb ,washer1 ,winterthur1 #bdj ,washers1 #ahd ,wear1 premature1 #adf ,witz apparatus1 #bhd ,wood as fuel1 #bed ,wood1 calorific value1 #aid ,wood-gas1 #aec1 #afh ,wood-gas1 purification of1 #aie ,wood in producers1 #aij1 #aib1 #aic ,work1 definition of effective1 #fj ,,advertisements ,,the ,,mietz ,,weiss ,,oil ,,engine ,,stationary ,,marine #a to #ge ,h4,p4 #a to #fj ,h4,p4 ,illustration #ej ,h4,p4 ,,generator ,,set ,,kerosene ,,or ,,fuel ,,oil 99 99 99 99 99 ,air ,compressors1 ,generator ,sets1 ,hoisting ,engines 99 99 99 99 99 ,centrifugal and ,triplex ,pumps and ,engines ,direct ,coupled ,medal of ,excellence--,american ,institute1 #ahig4 ,highest ,award for ,direct ,oil ,engine1 ,generator ,set--,paris ,universal ,exposition1 #aijj4 ,gold ,medal--,pan-,american ,exposition1 #aija4 ,gold ,medal--,charleston ,exposition1 #aijb4 ,gold ,medal--,louisiana ,purchase ,exposition1 #aijd4 ,a4 ,,mietz #hg-hi ,elizabeth ,st4 #abh-ach ,mott ,st41 ,new ,york ,,splitdorf ,,jump-,,spark ,,ignition ,,apparatus ,constructed ,the only ,real to give ,good ,illustration ,standard ,satisfaction ,high ,tension ,permanently ,apparatus ,f4 ,,splitdorf #ag-bg ,vandswater ,street1 ,new ,york1 ,n4,y4 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are engaged in any branch of industry will find this book of the greatest practical value1 and we especially commend it to those who are in search of an independent business1 as they will find many formulae for the manufacture of salable articles which will be worth many times the cost of the book4 ,the ,appendix contains the very latest formulae as well as #da tables of weights and measures1 and a dictionary of chemical synonyms4 ,illustration ,,send ,,for ,,full ,,table ,,of ,,contents4 ,,munn ,,co41 ,publishers1 ,,scientific ,,american ,,office4 #cfa ,broadway1 ,new ,york4 99 99 99 99 99 ,transcriber's ,notes ,blank pages have been deleted4 ,illustrations may have been moved4 ,the following publishers' errors and inconsistencies were corrected as noted3 ,fig4 #ei3 ,thermo-siphon was ,thermo-syphon4 ,page viii3 ,if ignition occurs too was ,if ignition occur too ,page #ah3 smoke-stack was smokestack4 ,page #ai3 ,split illustrations and titled one ,fig4 #a;a4 ,page #gj3 ,rearranged table4 ,page #hc3 sawdust was saw-dust4 ,page #hc3 #i feet by #ae feet was #i feet by #ge feet 7math error74 ,page #ib3 crank-shaft was crankshaft4 ,page #ib3 fly-wheel was flywheel4 ,page #aje3 thermo-siphons was thermo-syphons4 ,page #abh3 gas-pipe was gaspipe4 ,page #agd1 #bjj1 #bjc7b places73 horse-power was horsepower4 ,page #bje3 super-heater was superheater4 ,page #bbj3 air-tight was airtight4 ,page #bci3 superheated was super-heated4 ,page #bee3 potash was postash4 ,page #bfd3 #ei degrees ,f4 was #dij degrees ,f4 7conversion error74 ,page #bfi3 drum p'' was drum p'4 ,page #bia3 ,fig4 #aej has been split into two figures4 ,page #big3 ,stroke was ,stoke4 ,page #cjj3 ,ziehe was ,zi he4 ,page #cja3 ,messrs4 was ,me rs44 ,page #cbc3 ,,for was ,,fof4 ,index3 ,fire-box was ,firebox4 ,index3 ,governors1 444 hit-and-miss was hit-and miss4 ,index3 ,piston 444 crank-shaft was crankshaft4 ,advertisements3 ,chapter header ,,advertisements added4 99 99 99 99 99