1 
 
 STATIONARY 
 
 Steam Engines; 
 
 ESPECIALLY AS ADAPTED TO 
 
 ELECTRIC LIGHTING PURPOSES. 
 
 ^_ 
 
 "7 
 
 By ROBERT H. THURSTON, A. M., C. E., 
 
 \| 
 Formerly of the U. S. N. Engineer^ Corps ; Professor of Engineering at the 
 
 Stevens Institute of Technology; Past President American Society 
 Mechanical Engineers; Member American Society Civil Engi- 
 neers; American Institute Mining Engineers, Etc. 
 
 P<M l*tfc 
 
 JOHN WILEY & SONS, 
 15 Astor Place. 
 
 1884. 
 
751 
 
 Copyright, 1883, Electrician. 
 
 Copyright, 1884, R. H. Thurston. 
 
 
PREFACE. 
 
 THE following pages were written at the request of the 
 editor of the Electrician and Electrical Engineer, from 
 the columns of which periodical they have been reprinted. 
 It was desired that a concise, yet tolerably complete, ac- 
 count should be given of the changes which have taken 
 place during the years which have elapsed since the mod- 
 ern steam engine began to find application in modern in- 
 dustries, and especially those which have been brought 
 about by the demands of the last established of those in- 
 dustries — electric lighting — and which have been the result 
 of unprecedentedly exacting conditions as to efficiency, 
 regulation, and smooth action at high speed of rotation. 
 
 The subject was deemed to be of great importance to all 
 mechanical engineers in any way connected with this latest 
 department of their professional work ; and it was desired 
 that a systematic outline should be given of the history of 
 the development of the now standard type of engine for 
 " electric lighting plants" from the older, and still standard, 
 types of stationary engine, in such form that readers should 
 be able to compare the causes of such changes, with the 
 modifications of construction and operation to which they 
 have given rise. This the writer has endeavored to do, 
 giving a philosophical account of this evolution of the later 
 forms of engine, and of the stage to which it has progressed, 
 while, at the same time, presenting correct descriptions of 
 the forms and construction of representative machines. 
 It has been his endeavor to do full justice to the several en- 
 gines described, and he has carefully avoided the expression 
 of merely personal opinion in regard to debatable points. 
 
 R. H. Thurston. 
 Stevens Institute of Technology, 
 Hoboken, N. J., 
 May, 1884. 
 
CONTENTS. 
 
 ART. PAGE 
 
 I. — Historical Development of the Steam Engine. 3 
 
 II. — Principles of Economy ; Special requirements. 9 
 
 III. — Engines indirectly connected. 
 
 The Corliss Engine 17 
 
 The Wheelock Engine 32 
 
 The Greene Engine 36 
 
 IV. — Engines capable of direct connection. 
 
 The Porter- Allen Engine 52 
 
 " Buckeye " and Hartford Engines 69 
 
 The Cummer Engine 82 
 
 The " Straight-Line " Engine 97 
 
 The Armington & Sims Engine . 116 
 
 V. — Fast Engines of peculiar design. 
 
 The Ball Engine 136 
 
 The Ide Engine 148 
 
 N. Y. Safety Steam Power Co 155 
 
 Ericsson and Westinghouse Engines •• • • 162 
 
 Retrospect 176 
 
Steam Engines 
 
 FOR ELECTRIC LIGHTING PLANTS. 
 
 BY ROBERT H. THURSTON. 
 
 I. 
 
 Historical— The Development of the Steam Engine. 
 
 r | A HE growth of the steam engine into the forms now 
 -1- familiar to everyone who takes the slightest interest 
 in this most important of modern mechanisms, has occurred 
 by a series of transitions which is easily traced, and which 
 is especially interesting to every thoughtful mechanic as 
 representing the steps in a steady progression, toward ideal 
 perfection, of which the end is not yet seen. 
 
 A century ago, James Watt had just begun to introduce 
 the first engines belonging to a, then, new type. 1 A century 
 before (1698), the ingenuity and practical skill of Captain 
 Savery, had conferred an enormous benefit upon the mining 
 industries, and through them upon the world, by applying 
 the " fire engine " of the Marquis of Worcester to raising 
 water from the then rapidly deepening mines. 2 Savery used 
 steam of 8 to 10 atmospheres (120 to 150 pounds) total 
 pressure, in some cases,and he is entitled to fame as the first to 
 introduce that now familiar concomitant of civilization, the 
 
 1. History of the Growth of the Steam Engine. International Series. N. Y., 
 D. Appleton & Co. 
 
 2. The writer finds this engine described in Harris's "Lexicon Technicum" of 
 1704, of which, now rare work, he is so fortunate as to possess a copy. 
 
STEAM ENGINES FOR 
 
 steam boiler explosion. The usual pressure was 3 atmos- 
 pheres. These engines demanded about 30 pounds of coal, 
 per horse-power per hour, as a minimum. The apparatus 
 of Savery was not what would to-day be called a 'Steam 
 engine, at all. It was not a train of mechanism, involving 
 moving parts, cylinder, piston, crank and fly-wheel, but 
 either a single pair of closed vessels, or three vessels, one of 
 which was a boiler, and the other, or others, metal chambers 
 of spherical, cylindrical, or ellipsoidal form, which were at 
 once condensers and pumps. The latter were filled with 
 steam, which being condensed, the water rose into, and 
 filled them, and was then forced out by a succeeding charge 
 of steam, of pressure exceeding that of the head against 
 which the lift took place. Huyghens (1680), and Papin 
 (1690), proposed true engines with steam pistons traversing 
 their cylinders, and forming, on the whole, much such a 
 train of mechanism as is now so well known 3 ; but the 
 Newcomen engine was the first of this type to come into 
 practical use. This machine, then called the " Atmospheric 
 Steam Engine," consisted of a steam cylinder, with a piston 
 taking steam beneath, the upper end of the cylinder being 
 open to the atmosphere, the piston actuating a " working 
 beam," or " walking beam," and, through the latter, work- 
 ing pumps attached to the opposite end. Neither crank, 
 shaft, nor fly-wheel was used ; the action of the engine was 
 controlled entirely by the adjustment of its valves. In its 
 operation, steam at a little higher than atmospheric pressure, 
 was admitted below the piston ; the weight at the pump end 
 depressed that extremity of the beam, raising the piston. 
 
 3. Mem. Acad. Sci. Paris, 1680. Acta Emditomm. Leipsic, 1690. 
 
ELECTRIC LIGHTING PLANTS. 
 
 The steam below the piston was then condensed by a jet 
 of water thrown into the cylinder, producing a vacuum; and 
 atmospheric pressure finally forced the piston down, rais- 
 ing the pump-rod and plungers. The weight on the latter 
 was adjusted to the work, so that, when steam was admitted, 
 this weight should force the pumps to discharge the water. 
 The only function of the steam was the displacement of the 
 atmosphere, or counterbalancing it, by entering below the 
 piston, and thus permitting the formation of a vacuum. A 
 writer of that time states 4 that "Mr. Newcomen's invention 
 of the fire engine, enabled us to sink our mines to twice the 
 depth we could formerly do, by any other machinery "; but 
 " every fire engine of magnitude consumes ,£3,000 worth of 
 coal per annum." The coal consumption was, at best, about 
 20 pounds per hour and per horse-power. Smeaton, the 
 greatest civil engineer of his time, put up many of these 
 engines in Holland and elsewhere, as well as in Great 
 Britain ; some were 66 inches in diameter of cylinder, and 
 8 to 9 feet stroke of piston. It was this engine that Watt 
 found in operation, when he entered upon the stage. 
 
 Watt was not simply a mechanic ; he was a real philoso- 
 pher, and a truly scientific investigator. A model New- 
 comen engine, having been brought to him to be repaired, 
 he took advantage of the opportunity to study the principles 
 of its construction, to ascertain its defects, and to devise 
 proper remedies. He found that the sources of loss were 
 the conductivity, and radiating power of the steam cylinder, 
 the alternate heating and cooling of the metal at each stroke, 
 the imperfect vacuum, and the wastes from boiler and 
 
 4. Mineralogia Cornubiensis. Price. 1778. Appendix. 
 
STEAM ENGINES FOR 
 
 steam pipes. To correct these defects, he clothed his 
 boilers and steam pipes with non-conductors, sometimes 
 even making boiler shells of wood. Smeaton had already 
 covered the pistons and cylinder heads with wood. Watt 
 made a small wooden steam cylinder, and obtained great 
 economy ; he made a more practicable improvement, how- 
 ever, when he devised the steam jacket. He attached a 
 separate condenser to prevent the loss due to the introduc- 
 tion of condensing water into the steam cylinder, closed the 
 cylinder at the top, made the engine double-acting, and 
 finally adapted the engine to drive machinery, fitting it with 
 shaft and fly-wheel, throttle valve, and governor, and thus 
 making the steam engine such as we see it to-day, in all es- 
 sential particulars, not excepting the steam jacket, and the 
 arrangement of its valve gear to secure economy by the 
 expansion of the steam. His engine was substantially com- 
 plete by the year 1784. 5 
 
 Later changes have been a succession of refinements, 
 and of developments in application. Stephenson, and his 
 contemporaries, applied steam on railroads ; Stevens, Fitch, 
 and Evans, and, finally, Fulton, in the United States, and 
 Bell and others, in Europe, introduced steam navigation ; 
 Sickels invented the " detachable " cut-off valve gear ; 
 Corliss introduced the peculiar type of engine that has 
 given him a world-wide fame, and so attached its governor as 
 to determine the point of cut-off automatically, and thus to 
 regulate the engine ; and, a little earlier, Robert L. and 
 Francis B. Stevens designed the American river steamboat, 
 and its beam engine, with so simple and effective a valve 
 
 5. History of the Growth of the Steam Engine. P. 119. Farey on St. Engine. 
 
ELECTRIC LIGHTING PLANTS. 
 
 gear that it remains, to-day, still standard. The compound 
 engine, even, was brought oat by contemporaries of Watt, 
 and thus every prominent feature and essential detail of 
 the modern steam engine was introduced at, or before, the 
 middle of the nineteenth century. 
 
 Yet, practice has been steadily changing during the cen- 
 tury, and the form and proportions of the steam engine, and 
 the methods of steam distribution, have been undergoing 
 constant changes. In the time of Watt, steam was worked 
 at about 7 pounds pressure, per square inch, in stationary 
 engines; they were always fitted with condenser and air- 
 pump, and were slow in movement, and were, consequently, 
 of small power in proportion to their size; they wasted heat 
 and fuel to such an extent, as to demand 6 or 8 pounds of 
 coal per horse-power and per hour. It is true that Wolff, 
 in 1804, expanded 6 or 8 times, using higher steam and ob- 
 tained the horse-power with 4 pounds of fuel per hour, and 
 that John Stevens and Oliver Evans, in the United States, 
 and Trevithick, in Great Britain, had already used still 
 higher steam in non-condensing engines; but these examples 
 simply illustrated the fact, now familiar to every student of 
 philosophical history, as pictured by Draper, Buckle and 
 Whewell, that isolated examples which lead standard practice 
 by a half century or more, are to be observed during the 
 growth of every art. Recognized standard practice is al- 
 ways as conservative as it is permitted to be by trade com- 
 petition, and usually changes very slowly. Principles may 
 be discovered and understood, and a correct theory of de- 
 sign and of practice may be made generally familiar, and 
 often is, in a brief period; but the growth of application 
 
STEAM ENGINES FOR 
 
 and the familiarizing of constructors and operatives with 
 new mechanisms, and new methods of management, re- 
 quires time, and is slow at best. Thus it has happened, 
 that although the principles of steam engine economy were, 
 in the main, well understood by James Watt, and some of 
 his competitors, nearly a century ago, and have become 
 well settled in later years, we are still far from a completely 
 satisfactory solution of the problem, which, as stated by 
 the writer elsewhere, may be enunciated thus: — ' To con- 
 struct a machine which shall, in the most perfect manner 
 possible, convert the energy of heat into mechanical 
 power, the heat being derived from the combustion of 
 fuel, and steam being the receiver and conveyer of that 
 heat" 
 
ELECTRIC LIGHTING PLANTS. 
 
 II. 
 
 Principles of Economy ; Special Requirements. 
 
 THE principles of economical working, noted by James 
 Watt, and plainly stated by him, were but slowly 
 recognized by others, and the improvement of the steam 
 engine was, for many years, correspondingly slow. The 
 principles that must govern the engineer, in the attempt to 
 secure highest efficiency, may be summarized thus: 
 
 i. The greatest practicable range of commercially 
 economical expansive working of steam must be adopted; 
 the fluid must enter the cylinder at the highest admissible 
 pressure, and must be expanded down to the minimum 
 economical pressure at exhaust. 
 
 2. The wastes of heat must be made the least possible; 
 all loss of heat by conduction and radiation from the engine 
 must be prevented, if possible, and the usually much more 
 serious waste which occurs within the engine, by transfer 
 of heat from the steam side to the exhaust, by "cylinder 
 condensation " and re-evaporation, without doing its pro- 
 portion of work, must be checked as completely as is 
 practicable. This latter condition, as well as commercial 
 considerations, limits the degree of expansion allowable. 
 It also dictates high speed of engine. 
 
 3. The largest amount of work must be done by the 
 engine that it can perform, with due regard to the preced- 
 ing conditions. This condition compels us to drive the 
 engine up to the highest safe speed, and to adopt the high- 
 est practicable mean steam pressure. 
 
STEAM ENGINES FOR 
 
 The first two of the above requirements give maximum 
 efficiency of fluid, consistent with commercial economy, and 
 the latter gives highest efficiency of machine. In addition 
 to these requisites, which are not peculiar to any style of 
 engine, or to any one of the innumerable applications of 
 steam power, the adaptation of the machine to driving the 
 dynamo-electric apparatus of an electric lighting plant, 
 compels the designing and constructing engineer to meet 
 certain demands which, although not peculiar to this work, 
 are, nevertheless, more imperative here than elsewhere. The 
 principal of these requirements are effective regulation, 
 compactness, simplicity of parts, strength and durability, 
 and small cost, both of original purchase and of repairs. 
 In the attempt to meet these demands, the modern "high 
 speed engine " has gradually taken shape. 
 
 In the time of Watt, a pressure of seven pounds of 
 steam, with condensation, and a low piston speed, equal, 
 usually, in feet per minute, to about one hundred and 
 twenty-eight times the cube root of the length of stroke, 
 according to Watt's own rule, represented standard practice. 
 As time went on, steam pressures and piston speeds gradu- 
 ally rose, and when, in 1849, Corliss brought out the typical 
 modern "Drop Cut-off Engine" pressures of sixty pounds, 
 and speeds of piston reaching 450 feet per minute were 
 becoming usual. At such speeds, the "drop cut-off" was 
 thoroughly effective, and the steam valve, detached from 
 the driving mechanism, fell into its seat with sufficient 
 promptness and accuracy, as to time of closing, to do good 
 work; the governor had no other work to do than to detach 
 the valve, and was thus able to regulate with an exactness 
 
ELECTRIC LIGHTING PLANTS. 
 
 that is still beyond competition. These engines are very 
 extensively used to drive the smaller electric light machines, 
 and particularly where a considerable number are to be 
 driven together; they are not adapted to the work of driv- 
 ing the large " dynamo," where it is desired to couple 
 direct from crank-shaft to armature. 
 
 As piston speeds increased, the drop cut-off became less 
 satisfactory, where the load was variable. It became slowly 
 understood, among builders and users of engines, that one 
 important element of economy of fuel and cheapness in 
 cost of engine is the maximum speed of engine consistent 
 with endurance and safety. Speeds were, after a time, 
 rapidly increased, the Porter-Allen engine leading in this 
 movement, and small engines, working at high speed, dis- 
 placed large engines of the older type. It soon became 
 evident that this change must lead to the re-introduction 
 of the " positive motion " classes of valve gear and expan- 
 sion gear that Sickles, Corliss and Green had temporarily 
 displaced, notwithstanding the fact that these builders had 
 greatly increased the speeds of their engines. All the so- 
 called " high-speed engines," which are best knowri in the 
 market, are of this later type. The slower running engines 
 are nearly all fitted with governors of the fly-ball class, 
 geared, or belted, to revolve at a much higher speed than 
 the engine itself ; but the great velocity of rotation of the 
 new engines, from 200 to 500 revolutions per minute, in 
 the small sizes, and often a piston speed of about 800 
 times the cube root of stroke, permits the attachment of the 
 governor directly to the shaft; and this is done in the later 
 styles. This change of position of the governor, in turn, 
 
STEAM ENGINES FOR 
 
 has led to a change in its construction. The balls, instead 
 of being hung from a vertical revolving spindle by arms 
 pivoted on that spindle, are attached to arms carried on the 
 main shaft, or the driving pulley, and revolve in a vertical 
 plane at right angles to the shaft; they are held in place 
 against the action of centrifugal force by springs, and 
 arranged to adjust the eccentric, and to vary the expansion, 
 in a manner which will be plainly seen when studying their 
 construction in the later sections of this paper, in 
 which these engines will be described with the aid of care- 
 fully made engravings. The high speed engine, as adapted 
 to the work of directly driving the "dynamo," therefore, 
 may be described as a high pressure, non-condensing 
 engine, of short stroke, and high speed of rotation, with a 
 positive-motion valve-gear, and regulated by a governor, 
 which is usually mounted on the shaft, and so attached as 
 to alter the expansion by varying the lead of the valve. 
 Its essential features are high speed of rotation, good regu- 
 lation by a positive gear, economy, simplicity, and compact- 
 ness. It is this engine only, which is found to do good 
 work under these peculiarly exacting conditions. 
 
 It is proposed to study the best known engines of this 
 and the earlier classes, and to compare them, with a view 
 to bringing out their peculiarities and their special merits, 
 while the purchaser will, besides, study the machine which he 
 proposes to buy, to determine whether its material and work- 
 manship are as excellent as are the principles of its design. 
 
 The conditions demanded can here be merely outlined, in 
 the following resume 1 of the requisites of successful practice: 
 
 1. Report on Machinery and Manufactures. R. H. Thurston. Vol. in. 
 Reports of the Scientific Commissioners of the United States to Vienna; 1873. 
 
ELECTRIC LIGHTING PLANTS. 13 
 
 1. A good design, by which is meant: 
 
 a. Correct proportions, both in general dimensions 
 and arrangements of parts, and proper forms and 
 sizes of details to withstand safely the forces which 
 may be expected to come upon them. • 
 
 b. A general plan which embodies the recognized 
 practice of good engineering. 
 
 c. Adaptation to the specific work to be performed, 
 in size and in efficiency. It sometimes happens that 
 good practice dictates the use of a comparatively 
 un-economical design. 
 
 2. Good construction, by which is meant: 
 
 a. The use of good material. 
 
 b. Accurate workmanship. 
 
 c. Skillful fitting and a proper " assemblage " of 
 parts. 
 
 3. Proper connection with its work, that it may do that 
 work under the conditions assumed in its design. 
 
 4. Skillful management. 
 
 In the endeavor to secure these requisites, it is generally 
 advisable to use steam at a pressure not far from one hun- 
 dred pounds per square inch. The benefits of increasing 
 pressure diminish so rapidly above this point, that it is not 
 yet certain whether it will, with existing engines, pay to 
 carry pressure much higher. The ratio of expansion is to 
 be determined with reference to this pressure, as well as to 
 size of engine. It will usually be found even more wasteful 
 to cut-off too short than to " follow " too far; and Rankine's 
 principle of adjusting this point by consideration of the rel- 
 ative cost of large and small engines, as well as the princi- 
 
14 STEAM ENGINES FOR 
 
 pies controlling the economy of fuel, dictate, that for these 
 engines, which are nearly always non-condensing and un- 
 jacketed, the ratio of expansion must usually be low — say 
 from three to five, as higher pressures range from sixty to 
 one hundred pounds per square inch 2 — and that the termin- 
 al pressure shall usually be kept some five or ten pounds 
 above that of the atmosphere. 
 
 Moderate " superheating " is found advantageous ; but 
 it is seldom carried beyond about a hundred degrees above 
 the normal temperature of the steam. " Steam jacketing/' 
 as practiced in nearly all compound engines, is of advant- 
 age; but is not usually considered to pay for the added cost 
 and risk in engines of the class here considered, and espe- 
 cially in high-speed engines. The " compound " engine has 
 not found a place in this field. Smeaton's idea — or rather 
 Watt's, first attempted on a large scale by Smeaton — of sur- 
 rounding the working fluid with non-conducting surfaces, 
 is not yet found practicable with the high steam pressures 
 and temperatures now usual. Its final adoption, however, 
 is beyond doubt, as it is a far more promising system of 
 economizing heat, now wasted, than either superheating or 
 steam jacketing. The latter, indeed, is a method of intro- 
 ducing a waste to check greater loss. 
 
 Careful protection of external heated surfaces of the 
 cylinder against losses by conduction or radiation, is always 
 practiced where it can be conveniently done, and parts 
 which cannot well be so covered are highly polished. A 
 well polished surface transmits very little heat. 
 
 Back pressure, a frequent cause of waste of power, is 
 
 2. Ibid. Pp. 17, 18, 49. 
 
ELECTRIC LIGHTING PLANTS. 15 
 
 reduced by making the exhaust parts large, and the exhaust 
 opening of the valve rapid, and by giving "lead" to 
 the exhaust, so that the steam shall leave the cylinder just 
 before, rather than just after, the return stroke begins. 
 
 Friction is reduced to a minimum by carefully propor- 
 tioning the journals, and by securing free and continuous 
 lubrication with a good oil or grease. 
 
 An engine in which all the above requirements are fully 
 met is certain to be a good machine. 
 
 It is not proposed to compare the steam engine with the 
 gas engine, or with other motors. The gas engine is, in 
 many cases, likely to prove useful in consequence of its 
 compactness, cheapness of first cost, freedom from ris!;, and 
 small expense for attendance ; but it is expensive in use of 
 fuel, and is rarely as little liable to annoying interruptions 
 of operation as the steam engine, and also possesses other 
 minor disadvantages. Nevertheless, Otto and Clerk, and 
 other inventors and constructors, have greatly improved this 
 machine of late, and have brought the expenditure, in ten- 
 horse engines, down to twenty cubic feet of gas, or less, per 
 hour and per horse-power ; and although this is still double 
 the theoretical figure, no one can say how soon the latter 
 consumption may not be much more closely approximated 
 to. The gas engine is certain to find work in this direction. 
 Hot air engines, as yet, give less promise ; but it would be 
 rash to predict their total exclusion from the field. 
 
 Water-wheels, especially when used exclusively for sup- 
 plying power to the lighting plant, are, where available, 
 thoroughly satisfactory prime movers. 
 
 In studying the steam engine from the standpoint here 
 
16 STEAM ENGINES FOR 
 
 taken, we will divide them, first, with reference to their 
 method of driving the dynamo-electric machine, into two 
 classes : 
 
 i. Engines which may be used in driving by belt, and 
 which are not adapted for direct connection. 
 
 2. Engines especially designed and constructed to be 
 coupled directly to the " dynamo." 
 
 The first class of engines is in very extensive use, and 
 is, by many of the more conservative engineers, still pre- 
 ferred to the second. The latter constitute the so-called 
 " modern " type of engine, and are gradually coming into 
 use, some engineers adopting them, both for direct and for 
 indirect connection. The best engineers are not yet fully 
 in accord in regard to the question, whether they have 
 passed the experimental stage. 
 
ELECTRIC LIGHTING PLANTS. 17 
 
 III. 
 
 Engines Indirectly Connected, only. 
 
 THE CORLISS ENGINE. 
 
 T~~\IVIDING engines used in driving dynamo-electric 
 *S machines into two principal classes — engines driving 
 indirectly through gearing or belting, and engines directly 
 connected to the armatures — we may profitably devote con- 
 siderable space to the first class. And, although machines 
 of the kind which have come to be distinguished by the 
 appellation "high-speed engines" may be, and often are, 
 indirectly connected, it is proposed to leave the examina- 
 tion of such engines to a later article on directly connected 
 engines, and here to describe only the " drop-cut-off " 
 engines, or those with u detachable valve-gear," which can 
 only drive the armature of the "dynamo" indirectly. 
 
 The first drop cut-off introduced, had a form patented by 
 Fred. E. Sickles, in 1841. This engine was first built for 
 mill purposes, by Thurston, Gardner & Co., at Providence, 
 R. I., that firm then holding the Sickles' patents, except that 
 the marine engine business was retained by Sickles. The 
 modern stationary engine was thus introduced, and was 
 soon extensively made known among steam users by its 
 superior performance when competing with the older engines, 
 which were then usually arranged to expand steam about 
 one and a half times by the lap of the single three-ported 
 valve. A few engines were built of a better design, fitted 
 with an independent cut-off valve on the back of the main 
 
18 STEAM ENGINES FOR 
 
 valve. These two last named engines would, at best, with 
 good boilers use five or six pounds of coal per hour, and 
 per horse-pow T er, where the Sickles valve-gear would bring 
 the consumption down to four. 
 
 Regulation was always effected by a governor controlling 
 a throttle valve. This governor was usually a common fly- 
 ball governor, and its deficiency in power and lack of 
 isochronism, the distance of the regulating valve from the 
 engine valves, and the range of motion required in its 
 operation, and the resistance offered by the packing of the 
 steam, altogether, made this combination a very ineffective 
 regulating apparatus. Thurston, Gardner & Co., sub- 
 stituted for this the Pitcher hydraulic regulator and a 
 register valve, which gave a much better regulation; this 
 contrivance was also isochronous, /. e. y it was capable of 
 holding the engine at speed, whatever the variation of 
 steam-pressure or of load. 
 
 But an immense step in advance of this, then, best prac- 
 tice was made by Geo. H. Corliss, a young Providence me- 
 chanic, who had exchanged the rdle of sewing-machine inven- 
 tor for that of the inventor of the most famous steam engine 
 that has appeared since the time of Watt. The Corliss engine 
 was patented in 1849, and rapidly came into use, its re- 
 markable economy, when competing with the best existing 
 engines, the peculiar business tactics of its builder, and the 
 rapidly increasing demand for efficient, and especially well 
 regulated, engines, combining to give it a wonderfully rapid 
 introduction. 
 
 The engine is an interesting illustration of a machine 
 which is the representative of a peculiar type, each detail 
 
ELECTRIC LIGHTING PLANTS. 
 
 of which is especially adapted to its place in that machine, 
 and is characteristically different from the parts which per- 
 form the same office in other engines. The leading features 
 of this machine are: 
 
 i. The use of four valves — two steam, and two exhaust 
 — so placed as to reduce " clearance" to a minimum. 
 
 2. The use of a rotating valve, capable of being cheaply 
 and readily fitted up, of being easily moved, and of being 
 conveniently worked by connections outside the steam 
 spaces. 
 
 3. The use of a " wrist-plate," caused to oscillate by a 
 single eccentric, and directly so connected with all four 
 valves that each may be given a rapid opening and closing 
 movement, and be held open and nearly still, at either end of 
 its range, by swinging the line of connection nearly into the 
 line between centres, thus permitting nearly a full opening 
 of port to be maintained during an appreciable interval, 
 and a free and complete steam supply and exhaust. 
 
 4. A beautifully simple and effective method of detach- 
 ing the steam valve from the driving mechanism, and of 
 insuring its rapid and certain closure at the proper moment, 
 to produce any desired expansion of steam. 
 
 5. A direct connection of the governor, so as to deter- 
 mine the ratio of expansion, while so adjusting the power of 
 the engine to the work to be done, that the variation of 
 speed with changing loads becomes a minimum. 
 
 6. Making this latter adjustment in such a way as to 
 throw the least possible work on the regulating mechanism, 
 and thus to give the governor the greatest possible sensitive- 
 ness and accuracy of action. 
 
22 STEAM ENGINES FOR 
 
 7. A form of frame and general design of engine, which 
 gives maximum strength and stiffness, with least cost and 
 weight. 
 
 All these features are combined to form a steam engine 
 essentially different, in general and in detail, from the 
 engines contemporary with or succeeding it, except where 
 the latter may properly be classed as Corliss engines. It 
 rarely happens that an inventor succeeds in originating a 
 plan so wholly and so essentially novel; and it is still less 
 frequently the fact, that a peculiarly original device is 
 found superior to all competing machines. In operation, 
 the engine was found to exhibit a remarkable economy of 
 fuel, and a singularly perfect regulation, and to be far more 
 durable and more economical in cost of repairs, on the 
 average, than rival builders supposed possible. It very 
 soon took the leading place in the market. 
 
 The inventor established himself at Providence, and put 
 in operation a method of marketing his machine which 
 was as novel and as successful as the mechanical device 
 itself. He offered to put his engine in place of rival 
 engines, either with a guarantee of a certain saving, and at 
 a stipulated price, or, often, to take as his compensation 
 the actual saving shown on the books in a stated time. 
 This system was eminently satisfactory to the purchaser, 
 both as making him safe against loss, and as giving him 
 some of that confidence in the engine which the maker 
 himself unquestionably possessed. Corliss' work fully 
 justified his claims, and the expenditure of fuel was brought 
 down to between three and four pounds per hour, and per 
 horse-power, according to size and situation of the engine, 
 
ELECTRIC LIGHTING PLANTS. 23 
 
 with occasionally much better figures in condensing engines. 
 
 This engine is now built, not only by the Corliss 
 Steam Engine Co., under the eye of the inventor, but by 
 many other builders. It has found its way into every part 
 of the world ; and the engineer visiting Europe will find a 
 pleasure in observing the general adoption of this American 
 invention in every country, and for every purpose. Euro- 
 pean makers frequently modify the design, but rarely with 
 the desired effect of securing an improvement in cost or 
 efficiency, and very often with a decidedly contrary 
 result. 
 
 Corliss engines are now very frequently adopted in 
 electric lighting, and are always belted to the dynamos. 
 Their excellent regulation is as important a feature in this 
 application, as is their economy in use of steam. When 
 carelessly constructed, they are, of course, likely to prove 
 wasteful and irregular in action. But that these engines 
 can be made to give very perfect uniformity of rotation 
 will be evident, when it is stated that the writer, in testing 
 engines of this class, has found that the variation of speed 
 was so slight as to be practically inappreciable, even when 
 the amount of work thrown on or off, was a very large pro- 
 portion of that done by the engine when working at its rated 
 power. 
 
 One other reason for the success of this engine is un- 
 questionably the comparatively small cost of its construc- 
 tion, where competing with the earlier forms of engine with 
 detachable valve-gear. Its valve-faces, particularly, and 
 their seats, are surfaces of revolution, and they, as well as a 
 large part of the finished work about the engine, being 
 
24 STEAM ENGINES FOR 
 
 almost wholly lathe-work, the cost of fitting up is com- 
 paratively small. 
 
 In detail, the engine consists, as shown in the illustration, 
 page 19, of one of its standard forms, of a steam-cylinder 
 sustained by any substantial connection with the foundation. 
 The main pillar-block sustains the crank-shaft at the 
 opposite end of the machine, and a strong brace, connecting 
 these two pieces, forms, at the same time, a support for the 
 crosshead guides. 
 
 The four valves are placed at top and bottom of each 
 end of the cylinder, their rotating stems projecting, and are 
 moved by the "wrist-plate," set usually, as here, at the 
 middle of the cylinder, the valve connections radiating to 
 the four corners, where each is attached to the valve rock- 
 ing-arm, the exhaust by pin-connections, the steam by a 
 catch, which can be readily u tripped " by the adjustment 
 of a little cam set on the valve-stem, behind the arm. 
 When tripped, the steam valves are closed by a spring, or 
 in engines now built by Mr. Corliss, by a " vacuum-pot," 
 and by weights in his earlier engines, and in those of other 
 builders. 
 
 The governor is belted from a pulley on the main-shaft, 
 and its oscillations are controlled by a " dash-pot," seen 
 attached to the side of its standard. The governor, having 
 no work to do but to set the tripping-cam, or the equivalent 
 for it adopted by Corliss and others in various designs, is 
 entirely free to adjust itself to the normal position due the 
 speed of the engine, and thus is made perfectly capable of 
 doing the best possible work. Many foreign builders have 
 attached the Porter loaded governor to this engine. The 
 
ELECTRIC LIGHTING PLANTS. 25 
 
 advantage is less obvious here than in engines in which 
 more strength of action is needed. 
 
 From what has been stated, it is seen that the Corliss 
 engine came into use in consequence of its combination, to 
 an extent up to that time unequalled, of several special 
 features. Some of these points are not necessarily peculiar 
 to the Corliss type of engine; but they, nevertheless, were 
 peculiar to that engine at the time of its introduction. 
 The main points were : the rapid and wide opening of the 
 steam and exhaust openings; the shortness and directness 
 of the ports; the resulting small clearance and "dead" 
 spaces ; the quickness of closure of the steam valves ; 
 the adaptation of the main valve to the functions of 
 a cut-off valve ; the connection of the governor to the 
 cut-off gear in such a manner as to determine the point of 
 cut-off without being itself hampered by the connection ; 
 the location of the exhaust ports at the under side of the 
 cylinder so as to drain the cylinder thoroughly ; and the 
 simple, easily constructed form of the machine and of its 
 details. 
 
 The general form of the engine has been preserved 
 by nearly all copyists, and the parts of the valve gear 
 and details of regulating mechanism have been seldom 
 much modified. A few builders have, however, made 
 changes which are worthy of notice, but which we have 
 not time or space to study as they deserve. 
 
 The action of the Corliss engine is as follows i 1 
 
 The valves are driven by the eccentric rod through the 
 " wrist-plate/' E, vibrating on a pin projecting from the 
 
 1. History of the growth of the Steam Engine. D. Appleton & Co., N. Y. 1S78. 
 
26 
 
 STEAM ENGINES FOR 
 
 cylinder. Links, E D, E Z>, E F, E F, take motion, from 
 properly set pins on this wrist-plate, to the steam valve 
 rock-shafts, D, D y and to the exhaust valves, F, F y moving 
 them with a peculiar varying motion in such a manner as to 
 open and close the ports rapidly, and to hold them open, when 
 the valves are off the ports, in such a way as to give the 
 least possible loss of pressure during the exit or the entrance 
 of steam. The links leading to the steam valves are fitted 
 
 The Corliss Engine. 
 
 with catches, or latches, which may be disengaged, as the 
 valve opens, at any desired point within about half stroke; 
 and the time of this disengagement is determined by the 
 rotation of a cam seen on the valve stem above D y which 
 cam is rotated by the governor through the rod 77, leading 
 off to the left. The slowing of the engine, in consequence 
 of reduced steam pressure or of increased load, causes the 
 catch to hold its contact longer and the steam to follow 
 
ELECTRIC LIGHTING PLANTS. 
 
 27 
 
 farther, and the reverse. When the catch is disengaged, 
 the valve is closed by a spring or weight attached to the 
 
 w 
 p 
 g 
 
 U 
 
 W 
 
 t— 1 
 C3 
 
 W 
 
 o 
 U 
 
 w 
 
 w 
 
 vertical rods seen connected to the rock-shaft arm. Corliss 
 uses a device in place of this which is not here shown. The 
 
28 
 
 STEAM ENGINES FOR 
 
 dash-pots are under the floor, in the case here illustrated, 
 or on the column supporting the governor in the engines 
 just referred to. It is always an air dash-pot. The device 
 invented by Sickles was a water dash-pot. 
 
 The standard form of Corliss valve is very well exhibited 
 by the illustrations here given, which are taken from the 
 drawings of Mr. Harris. 
 
ELECTRIC LIGHTING PLANTS. 
 
 29 
 
 Those marked A are the steam, and those marked B are 
 the exhaust valves. Both consist, as is seen, of cylinders, 
 parts of which have been cut away, leaving the working and 
 bearing surfaces of no greater extent than is necessary to 
 subserve the purposes of the valve. These surfaces are of 
 the simplest possible form and are easily fitted up in the 
 lathe. In order that they may come to a bearing with cer- 
 tainty, and without regard to the position of the spindle 
 relatively to the valve, they are made with a longitudinal 
 slit into which fits, without jamming, the blade of the rock- 
 shaft. The valves are thus allowed to come to a bearing, 
 and even to wear down in their seats without causing leakage. 
 The next Fig. shows the arrangement of this valve as 
 seen in longitudinal section of the chest. As this maker 
 
 FT «/ 
 
 Harris-Corliss Valve. 
 
 constructs it, the stem goes through a fitted opening, with- 
 out stuffing box, and the slight drip is carried off from 
 the closed space at D ; thus none escapes into the 
 engine room. The steel collar at F, which is shrunk on 
 the stem, fits into the recess at a and serves as a packing. 
 As the tendency of the stem to shift outward always causes 
 
30 
 
 STEAM ENGINES FOR 
 
 the collar to wear to a fit, it is not likely often to wear leaky. 
 Another detail of interest in the Corliss engine is the 
 
 « 
 
 CO 
 
 a 
 
 I 
 
 o 
 
 "dash-pot." When the valve is suddenly closed, some 
 device is necessary to prevent jar at the instant of its com- 
 
ELECTRIC LIGHTING PLANTS. 3I 
 
 ing to rest. This device is the dash-pot. The form adopted 
 by Corliss consists of a shallow cup into which a piston on 
 the valve stem fits, cushioning the enclosed air, and thus 
 checking the motion of the valve without shock. This dash- 
 pot, made by Watts, Campbell & Co., who have successfully 
 introduced Corliss engines into electric light establishments 
 in New York city and elsewhere, is that seen in the Figs. 
 
 The annular piston, E y E, fits the cylinder, Z>, JD, E, E, 
 and a space, seen above B, forms a vacuum chamber which 
 assists the spring or weight, closing the valve by the form- 
 ation of a more or less complete vacuum, as the pis- 
 ton is raised while the valve is opening. A small cock, 
 not seen, is arranged to adjust the degree of ex- 
 haustion of this chamber. When the valve has nearly 
 reached its seat, the piston Z>, passes the opening from F 
 into the outer space and the enclosed air then acts as a 
 cushion, checking the movement of the valve. In the 
 engines of these builders, great care is taken to keep the 
 cold exhaust steam clear from the cylinder as it passes out, 
 in order to prevent the condensation which occurs where 
 this precaution is neglected. 
 
 Many Corliss engines are already at work driving elec- 
 tric lighting apparatus, and are giving good satisfaction, 
 according to the testimony given the writer by the officers 
 of the companies using them. One, built by the Corliss 
 Steam Engine Co., is at work at Providence, R. I., driving 
 nine dynamos, and a number are in use in New York city, 
 and other large cities of the United States and of Europe. 
 
 At how high a speed they can be operated with satisfac- 
 tion to the user is not definitely known. The writer has 
 
32 STEAM ENGINES FOR 
 
 known one of these engines, coupled to a fast running ro'l- 
 train, to be driven without apparent difficulty for several 
 years at a speed of 120 revolutions per minute, although of 
 four feet stroke. This engine is still running. Those who 
 use, as well as the engineers who build, this class of engines, 
 however, are apt to be conservative and to prefer the mod- 
 erate speeds with indefinite endurance, to higher speeds with 
 a shorter life of engine and greater cost in keeping in 
 repair; and to consider that the satisfaction of having a 
 prime motor, which is not likely during their business lives 
 to give them any trouble, is more than a compensation for 
 any possible saving in dollars and cents to be effected 
 by the adoption of the higher velocities of piston and of 
 crank-shaft rotation. 
 
 THE WHEELOCK ENGINE 
 
 is an ingeniously arranged engine of the class considered 
 in this division of the subject. 
 
 Its form is seen in the accompanying engravings. 
 
 The steam chest is placed below the cylinder and the 
 steam and exhaust valves are set side by side, the latter 
 serving both as induction and eduction valve, and having 
 the same action, nearly, as the common three ported slide 
 valve, while the function of the former is principally that of 
 a cut-off valve. The latter, or main valve, is set nearest the 
 end of the cylinder and the exhaust steam is thus permitted 
 to escape directly and promptly from the engine. The 
 valves are coned, slightly, and may be adjusted to take up 
 wear, or to relieve pressure on their seats. These valves 
 
ELECTRIC LIGHTING PLANTS. 
 
 35 
 
 are carried on steel trunnions, and with hardened surfaces 
 of contact are but little subject to wear. The steam or 
 cut-off valve is set further away from the cylinder than in 
 the standard arrangements of Corliss and other builders of 
 that class of engines, and this enables the maker of this engine 
 to secure a single port with reduced clearance and less 
 liability to leakage, should the expansion valve leak. In 
 this engine — and it should be the case in every engine in 
 which the regulator is driven by belt — the connection from 
 shaft to governor is so made that the breaking of the belt 
 permits an automatic closing of the valve and the stopping 
 
 The Wheelock Valves. 
 
 of the engine. The regularity of motion of the class of 
 engines described in this section, may be inferred from the 
 fact stated in regard to the engine here studied, that it has 
 been known to vary but a half revolution per minute when 
 five-sixths of the load was thrown off. 
 
 Engines of the class described in this section have dis- 
 played an economy in the use of fuel that has been rarely 
 equalled by the best type of compound engine, working 
 under the same conditions of steam supply. With good 
 
36 STEAM ENGINES FOR 
 
 boilers, they have given the horse-power with a consumption 
 of two pounds an hour for condensing engines, and three 
 pounds for non-condensing engines. They have quite 
 often demanded but a ton of coal for 100 barrels of flour 
 ground, in well arranged mills; and one and a quarter tons is 
 a very usual figure. A number of good makers are now 
 building such engines, and the purchaser can readily suit 
 himself if desirous of selecting an engine of any grade, either 
 as to cost or excellence of construction. They are well 
 adapted to driving either large or small electric lighting 
 plants; and, if purchased of a reliable maker, may be con- 
 fidently expected to give satisfaction. 
 
 THE GREENE ENGINE. 
 
 AT EARLY all u drop cut-off engines" are constructed, 
 like those described in the preceding article, 
 with a single eccentric, which drives both the steam 
 and the exhaust valves. Both sets of valves must, therefore, 
 have the same motion relatively to the piston, except so far 
 as their motion can be modified, as in the Corliss engine, by 
 the method of connection of valve and eccentric. They 
 must stop and start at the same instant, and their motion 
 during their travel must be more or less similar. But such 
 a system is controlled in its action by the necessary motion 
 of the exhaust valve. That valve must be adjusted to 
 open and to close very nearly at the beginning and 
 the end of the return stroke, in order that the exhaust 
 may be prompt and free, and that the compression shall 
 be right. The movement of the gear, on the steam side, 
 
ELECTRIC LIGHTING PLANTS. 39 
 
 must thus be also one which shall open the valve 
 to take steam at the commencement of the steam stroke, 
 and, if the valve is not tripped, close the port at the end 
 of that stroke. It is further evident, that if the valve is to 
 be detached by its own motion, it can only be tripped dur- 
 ing the forward part of its movement, and that, passing that 
 stage, and commencing to return before the cut-off takes 
 place, the valve must be allowed to remain undetached 
 until the end of stroke, and steam must follow full stroke. 
 An engine thus constructed, and so adjusted to its work as 
 to cut-off at about half stroke, will evidently, if the work or 
 the steam pressure becomes variable, be likely to operate 
 very irregularly, at one time cutting off at a little inside 
 half stroke, and then jumping to full stroke. This varia- 
 tion of steam distribution may thus itself introduce a dis- 
 turbing element, and the engine may give a very unsatisfac- 
 tory performance. Such an adjustment of power of engine 
 to the work to be done, does not often take place in engines 
 of the class which is here studied, as the best point of cut- 
 off is usually not far from one-third or one-fourth stroke, 
 and the variation in the load is not often great enough to 
 cause serious difficulty in the manner described above. 
 
 One advantage possessed by the arrangement of valve 
 gear, thus subject to criticism, is that, should, as sometimes 
 happens, the valve fail to close, or should it lag behind 
 very greatly, in fast running engines, it is certain that it 
 cannot be left open beyond the end of that stroke, as the 
 returning motion of the valve-gear will bring the latch into 
 gear again, and will insure its closing. Mr. Corliss con- 
 siders this point of sufficient importance to make it inex- 
 
40 STEAM ENGINES FOR 
 
 pedient to drive the steam valves by the method to be 
 described in this article. It is undoubtedly an advantage 
 to be able to secure such an arrangement of valve-gear 
 that the ratio of expansion may be varied by the governor 
 from the beginning to the very end of the stroke, so that 
 the engine may adapt its steam supply to any load that 
 may be thrown upon it, whatever the extent of that varia- 
 tion may be, and to cut-off at any point from end to end 
 of the stroke. This can be done by the adoption of a gear 
 of the class known, for many years past, from the time of 
 the earliest steam engines in fact, as the " plug-tree " form of 
 valve-gear. It was this class of gear that was used on engines 
 before the days of Watt, that greatest of inventors, for pump- 
 ing out the deep mines of Great Britain — the Newcomen 
 engine. It may be still seen in use on all so-called Cornish 
 engines, which are to be found in the water works of this and 
 other countries— the most costly, cumbersome, and unsatis- 
 factory style of engine which has been applied to that kind of 
 work in modern times. The distinguishing feature of this 
 gear, is, that it is so adjusted, that the motion of the valve is 
 produced, by a mechanism which begins and ends its move- 
 ment with the action of the piston; in the Cornish engine 
 it is actuated by the engine beam. It is easy to obtain a 
 motion of this character, by the use of an eccentric, by 
 simply setting it so as to make its throw directly with, or 
 opposite to, the crank. In such a case, it is seen that the 
 exhaust valve must be driven by an independent eccentric, 
 and the cost of the engine is thus somewhat increased. 
 This is not a large item, however. The " Greene engine M 
 is an engine fitted v/ith such a valve-motion. 
 
 
ELECTRIC LIGHTING PLANTS. 
 
 4i 
 
 In the accompanying illustration, 1 which exhibits this 
 machine, the valves are seen to be four in number, as in the 
 engines already described. They are flat valves, instead of 
 cylindrical, and are thought by the inventor to be better 
 than the latter, as being easier to refit when worn, and as 
 being less liable to become leaky. The cut-off mechanism 
 consists of a sliding bar, A, driven by an eccentric, set to 
 
 Greene Valve Motion. 
 
 give it motion parallel to the centre line of the cylinder, and 
 with a movement co-incident, as to time, with the motion 
 of the piston; of a pair of "tappets," C, C, set in this bar 
 
 1. Hist, of the Growth of the S^eam BvAu \ D. Applcton & Co. N. Y., 1878. 
 
42 STEAM ENGINES FOR 
 
 and adjustable vertically in such a manner as to engage the 
 rock-shaft arms, B, J3 9 on the ends of the rock-shafts, E, F, 
 which rock-shafts are attached to the valve-links inside the 
 steam chest; of a set of springs which hold these tappets 
 up to their work, and in contact with the " gauge-bar " 
 behind the bar, A, and out of sight in the drawing. This 
 gauge-bar is adjusted to the proper height, and is varied in 
 position, as the load varies, by the action of the governor 
 which is connected to the gauge-bar by the rod extending 
 up to it at G. The exhaust valves are seen below, and are 
 driven by the second eccentric there shown. They are so 
 placed as to thoroughly drain the cylinder of all water 
 carried into it by priming, or produced by cylinder con- 
 densation. The eccentric driving these valves is set 
 at right angles to the position of the crank. In con- 
 sequence of this independence of the two sets of valves, 
 this engine can cut-off at any point in the stroke during a 
 complete half revolution of the crank. This form of engine 
 was invented by a Providence mechanic, Mr. Noble T. 
 Greene, and was patented in the year 1855. Mr. Greene, 
 then of the firm of Thurston, Greene & Co., introduced this 
 engine a few years after the merits of the drop cut-off had 
 been proven by Sickles and Corliss so fully that it was easy 
 to secure a market for new devices of this class; and the 
 introduction of this engine has had much to do with the 
 rapid progress of these more economical kinds of engine. 
 
 The form of the engine has been somewhat modified at 
 various times, although its characteristic features have been 
 carefully preserved. The steam valve, as designed by the 
 writer, who, at the time of its first appearance, had an 
 
ELECTRIC LIGHTING PLANTS. 
 
 43 
 
 Thurston's Valve. 
 
 occasional opportunity to exercise his powers as a designer 
 on this engine, is seen in the next Fig. 1 
 
 The valve, G, H> cover- 
 ing the steam port, Z>, in the 
 cylinder, A, JB y is driven by 
 the rod, J y y, which is con- 
 nected to the rock-shaft, M, 
 by the arm, Z, K, in such a 
 manner that the line, K y 7, 
 will, when prolonged, inter- 
 sect the valve-face at its middle point G; it is thus so set 
 that the line of action of the link, K 9 f 9 meeting the valve 
 seat directly under the middle of the valve, does not 
 produce any tendency to rock the latter, and thus to cause 
 wear at the edges, or leaks of steam past the valve into the 
 port. 
 
 The latest form of the Greene engine, familiar to the 
 writer, is that now constructed by the Providence Steam 
 Engine Co., and shown in the large illustration, page 35. In 
 this engine, the steam valves are connected to the cut-off 
 mechanism, by a set of rods or stems running parallel to 
 their seats, and emerging into the air through stuffing 
 boxes, properly provided with easily set and easy working 
 packing; these valve stems are connected to the rock-shafts, 
 and are driven as in the arrangement already described, 
 very nearly; this design has some advantages over the old, 
 in keeping the working parts, and especially the joints, out 
 of the steam space. The exhaust valves are gridiron slides, 
 set to travel across the line of the cylinder, and driven from 
 
 1. Supplied by D. Apj leton & Co. 
 
44 
 
 STEAM ENGINES FOR 
 
 a horizontal rock-shaft, extending forward to the eccentric 
 on the crank-shaft; the governor is a Porter loaded 
 governor, driven by a belt from the main shaft; the cut-off 
 mechanism is illustrated in the last of this series of illustra- 
 tions. 
 
 Greene Trip Motion. 
 
 The tappets, A, A, are carried by the rock-shafts, J, 
 J, which, in turn, drive the arms, F y F y and the valves 
 attached to the stems, G, G, pas c ing through the stuffing 
 boxes, H, H; the tappets, B, I>, engage these rock-levers, 
 and are adjusted vertically by the governor rod, D y and 
 held up against the gauge bar or the rock-lever, as the case 
 may be, by the springs set in the sliding bar. When the 
 speed of the engine is above that for which the engine is 
 set, the governor, acting through the rod, D, depresses the 
 tappets, and they do not retain their connection with the 
 rock-lever as long as when at normal speed; when the speed 
 
ELECTRIC LIGHTING PLANTS. 45 
 
 falls below that fixed by the constructor, the governor rod 
 rises, and the tappets are thus permitted to rise, and to 
 remain in contact with the rock-lever, holding open the 
 steam valve for a longer period than before. The longer the 
 valve is to be kept open, and the farther the steam is to 
 follow, therefore, the wider does the port open to steam. 
 When the tappets travel to the point of cut-off, they swing 
 clear of the rock-levers; the weights, acting together with 
 the pressure of steam upon the valve-stem area, quickly 
 shut the port, and the steam is allowed to expand from that 
 point on to the end of stroke; the higher the tappets are 
 permitted to rise, by the elevation of the gauge-plate, the 
 greater the ratio of expansion; the further they are 
 depressed, the shorter the cut-off. As these engines are 
 constructed, they are capable of cutting off steam anywhere 
 between the beginning and three-quarters stroke; the latter 
 limit is determined by the lead, and by the margin thought 
 necessary to secure certainty of closure of the valve, when 
 tripped, before the piston reaches the end of its stroke. 
 To follow farther would not be likely to be of advantage, as 
 the gain in the mean total pressure would be compensated 
 by the loss due to a retarded exhaust. A safety stop- 
 motion is combined with the governor connection, in such 
 a manner, that if the belt breaks, or is thrown off its pulleys, 
 the steam will be at once shut off, and the danger of acci- 
 dents, such as sometimes occur with a run-away-engine, is 
 avoided. The valves and seats on the exhaust side are 
 both easily removable, from the outside, have outside con- 
 nections, and are readily adjusted without interference 
 with the steam side. 
 
46 STEAM ENGINES FOR 
 
 These engines have been, next to those of Corliss, the 
 pioneers in the movement, during the past generation, 
 toward economical working of steam. An engine built 
 upon this plan, substantially, by the firm of Thurston, 
 Gardner & Co., nearly a quarter of a century ago, from 
 designs prepared by Mr. E. D. Leavitt, Jr., for a well- 
 known Eastern mill, had steam -jacketted cylinders, 26^ 
 inches in diameter, 5 feet stroke of piston, made 50 revo- 
 lutions per minute, with steam at 100 pounds pressure in 
 the steam chest, and, on trial, worked down to a consump- 
 tion of 1.98 pounds of coal per horse-power and per 
 hour; the guarantee was 2 pounds. Its fly-wheel, designed 
 by the writer, who was then just out of college, weighed 
 about 20 tons, was fitted up as a mortice gear, with cut 
 hickory teeth, and was given extremely small side clear- 
 ance; the motion of the engine was so smooth, however, 
 that the presence of the gear was hardly noticeable. This 
 engine was fitted with the gridiron slides, as in the above 
 illustration; they were driven by sliding cams, thus ob- 
 taining a rapid opening and closing of the exhaust, and a 
 slow movement while in the intermediate position, with the 
 port either open or closed. This was a remarkably good 
 piece of work for that time, and has not often been 
 excelled since. 
 
 This engine, like other engines with drop cut-off valve* 
 motion, is not adapted to such high velocity of rotation as 
 to permit it to work safely at the speed of even the largest 
 and slowest of the modern " dynamos; " but, belted to the 
 machine, it will give as great economy, and as great per- 
 fection of regulation, as engines of the preceding class. It 
 
ELECTRIC LIGHTING PLANTS. 47 
 
 is evidently so arranged that no load is thrown upon the 
 governor, and the effort to detach the steam valve is, there- 
 fore, not liable to cause any oscillation in the cut-off gear, 
 or variation in the speed of the engine. In all these en- 
 gines, the difficulty met with by the designer is, not to 
 secure this independence of the governor from the action 
 of the valve-gear, but to prevent the irregularity which 
 comes of the oscillations of the governor itself. The dash- 
 pot attached to the governor, or, sometimes, a friction 
 mechanism, prevents such irregularity. 
 
 This valve-gear does not as conveniently adapt itself to 
 the vertical engine as some others, but one of the first 
 engine-cylinders ever designed by the writer, was built with 
 this gear, and was set vertically. It gave perfect satisfac- 
 tion, if the fact that it was never reported to the shop for 
 repairs, so far as the writer has yet heard, may be taken as 
 evidence of its successful operation. 1 
 
 This engine was introduced over a quarter of a century 
 ago, in the face of a strong competition from the Corliss 
 engine — a fact which is, perhaps, the best evidence that it 
 had merit — and by the same methods which Mr. Corliss 
 had proved so effective. Guarantees were given of per- 
 formance, and forfeitures were provided for in the contract; 
 or else the agreement was accepted to take as payment the 
 saving actually effected in a fixed period of time — usually 
 from two to five years, according to the character of the 
 machine displaced. One of these engines, with which the 
 writer was familiarly acquainted through his indicator, and 
 
 1. This engine is still in use, after 22 years service, and drives a set of 
 dynamos at South Webster Mass. 
 
48 STEAM ENGINES FOR 
 
 which displaced the rival engine on such a guarantee, has 
 now been in operation 23 years, and is reported to be to- 
 day still in perfect order. The engine referred to above as 
 having given so excellent a performance, was put in under 
 an agreement by which the builders agreed to forfeit $1,000 
 per ^ pound that the coal consumption should fall short 
 of the guarantee. The manufacture was interrupted for 
 some years by an injunction secured by Mr. Corliss, after 
 a suit brought by him for infringement, but was recom- 
 menced after the expiration of the Corliss patent, and has 
 proved a successful enterprise, notwithstanding the fact 
 that its constructors have depended, apparently, upon the 
 performance of the engine itself for advertisement — a con- 
 servative system of doing business which few manufacturers 
 adopt, at present. 
 
 All three of the great inventors and introducers of the 
 modern American type of steam engine — Sickles, who 
 brought into use the drop cut-off ; Corliss, who gave the 
 stationary engine its now standard form, as well as devised 
 his peculiar valve gear; Greene, who applied the principles 
 of this system of working steam to the plug-tree form of 
 valve gear, — are now still living. Mr. Corliss has acquired 
 wealth, as well as fame; his predecessor and his rival, how- 
 ever, have attained less fame — much less than they are en- 
 titled to, and still enjoy all the advantages which poets 
 ascribe to the possession of small means. Neither of them 
 expects to be able to build a monument, in the shape of a 
 great technical school, such as it is becoming customary for 
 wealthy engineers, like Stevens, and Rose, and Stone, to 
 erect. 
 

ELECTRIC LIGHTING PLANTS. 
 
 51 
 
 There are other engines belonging to the class here 
 considered — the engines having a detachable cut-off valve 
 closed independently of the motion of the valve-gear, — of 
 which the space proposed for these articles will not permit 
 description. Among these are the Wright engine, con- 
 structed by one of the oldest and best known designers in 
 the country; the Brown engine, a machine which has been 
 extensively adopted for driving mills in New England, and 
 is famous for the excellence of its workmanship and finish, 
 as well as for its durability and efficiency; the Fitchburg 
 engine, and others. 
 
52 STEAM ENGINES FOR 
 
 IV. 
 
 Engines Capable of Direct Connection. 
 
 THE PORTER-ALLEN ENGINE. 
 
 r I ^HE essentials, in the construction of the steam engine 
 -*- with a view to the economical production of power, 
 as has been seen in the introductory part of this series of 
 articles, include special provision against loss of heat and 
 condensation of steam, at entrance into the steam cylinder, 
 by the action of the metal surfaces to which it is exposed 
 on all sides at the beginning of the stroke. One of the 
 methods of securing this economy in the working of steam, 
 has been stated to be the driving of the engine up to the 
 highest safe velocity of piston, and giving it a maximum 
 speed of rotation. The time allowed for condensation of 
 each charge, and for the necessary change of temperature 
 preceding such condensation, is thus reduced, and the 
 amount of steam condensed being thus made a minimum, 
 in any given time, the percentage of loss of the increased 
 quantity of steam worked off by the engine becomes the 
 least possible. The engine does a greater amount of work, 
 and is subject to less loss. Thus the work to be done being 
 fixed, it is done by a smaller, and, other things being equal, 
 a less costly engine, and at the same by a more economical 
 machine. 
 
 Although this seems a sufficiently simple and axiomatic 
 philosophy, and although the general tendency of practice 
 in steam engineering had been plainly in this direction for 
 
ELECTRIC LIGHTING PLANTS. 55 
 
 many years, these points had not, up to a comparatively 
 recent time,been recognized by constructing engineers, and 
 their progress had been slow and difficult. The older firms 
 who were engaged in the building of what were then called 
 " expansion engines," were the first to detect this movement 
 and its cause, and they led off, in a very conservative way, 
 toward the construction of faster engines. The firms 
 already mentioned as leading in the movement toward cor- 
 rect practice, came up to speeds far ahead of those common 
 among other makers, and secured an advantage that was 
 sufficient to prove unmistakably that they were in the right 
 track. They did not, however, modify their designs in any 
 great degree, with a view to adapting them to very high 
 speeds. Their valve-gears were not of a kind well 
 fitted to high speed of rotation; the builders, were them- 
 selves disinclined to accept the risks undeniably attendant 
 upon rapid change in this direction, and the public to whom 
 they looked for a market were not educated up to such a 
 point as would make it safe to attempt to go on very 
 rapidly. A rather slow engine, with its comparative 
 immunity from risk of serious accident in case any little 
 derangement should occur, and with its greater durability 
 under the ordinary conditions of use, was, by the great 
 majority of designers, builders, and steam users, thought a 
 far better investment than a fast engine, however well 
 adapted to the radical illustration of a very interesting, but 
 apparently impracticable, philosophy. 
 
 The first man to take up this matter with a will, and 
 with a faith and a determination that were equal to the 
 task, was Mr. Charles T. Porter, a young lawyer turned 
 
56 STEAM ENGINES FOR 
 
 engineer, and Mr. John F. Allen, when the writer first knew 
 him, a skillful mechanic, who was showing the natural bent 
 of a real inventor, in the production of new devices, while 
 engaged in the management of some of the best engines of 
 20 years ago. The valve-gear of the Porter- Allen engine, 
 is the invention of Mr. Allen, and its governor and general 
 arrangement are due to Mr. Porter. It was Mr. Porter, 
 also, who, by his courage, persistence, skill in business, and 
 general good sense and management, finally, after years 
 of struggle to secure good construction and workmanship, 
 brought the engine into use in spite of every discourage- 
 ment, whether due to circumstances, to direct opposition of 
 competitors, or to public sentiment in favor of conservatism. 
 There are some interesting problems which present them- 
 selves to the engineer who attempts to design an engine to 
 be operated at very high speed — problems which are by no 
 means easy of solution, except to the boldest of innovators. 
 One of these points of difficulty has already been considered. 
 When the speed of revolution is increased, it is evident that 
 a limit must sooner or later be attained at which the drop 
 cut-off must be exchanged for some " positive mention " 
 gear. But the various forms of such gearing familiar to 
 engineers when Messrs. Porter and Allen became acquainted 
 with each other, years ago, the still common three-ported 
 valve, such as is used on locomotives, the Meyer valve with 
 its cut-off valve on the back of the main valve, and kindred 
 devices, were not adapted to the conditions sought by the 
 engineer looking for a good system of expansion. They 
 were simple and inexpensive, and could be used at any 
 practicable speed of engine; but they did not always give a 
 
ELECTRIC LIGHTING PLANTS. 57 
 
 satisfactory distribution of steam. They usually produced a 
 retarded steam supply, a " throttling " of the steam at the 
 point of cut-off, which was not at all such as would satisfy 
 the engineer familiar with the prompt action, and the 
 " sharp corners" of the indicator diagram from the class 
 of engine then taking the market. The dependence of the 
 several parts of the motion upon each other was another 
 objection to these devices, and the load which they threw 
 upon the governor was a fatal defect, as the governor was 
 then arranged and connected. Mr. Allen's invention placed 
 in the hands of Mr. Porter just the device that he needed 
 to carry out his idea of a fast engine. 
 
 This arrangement consists of a single eccentric driving a 
 link motion to operate the steam valve and to work the 
 exhaust at the same time. The link is controlled by a 
 Porter governor, and is so connected and driven that the 
 gear may be readily and quickly adjusted by the governor 
 to any desired point of cut-off. 
 
 The eccentric and link are shown in the next illustra- 
 tion. The eccentric is set on the shaft in such a position, 
 that its motion is co-incident with that of the crank. The 
 link is a slotted curved arm, forming one piece with the 
 eccentric strap, pivoted at the middle on trunnions sustained 
 by an arm rocking about a pin set in the bed of the engine. 
 The upper end of the link carries a pin, from which a rod 
 leads off to the exhaust, which is driven without variable 
 connections. The link-block is fitted to work in the slot 
 of the link, from the end nearest the exhaust rod pin, down 
 to the point opposite the pivotal point at which the trunnions 
 are set. When it is at the upper end, the throw of the valve 
 
58 
 
 STEAM ENGINES FOR 
 
 is a maximum; when at the lower point, it is a minimum. 
 As the link-block is moved up and down in the slot, the 
 motion of the valve is varied, and the ratio of expansion 
 correspondingly altered. By an ingenious adjustment of a 
 still more ingenious form of valve-motion, it is thus possible 
 
 The Allen Link. 
 
 to obtain a valve movement of perfect precision at all 
 speeds, and on both the forward and the backward stroke, 
 with a quicker closing action, as the cut-off is later. The 
 steam is. allowed to enter the cylinder, at nearly boiler 
 pressure, almost up to the point of cut-off, and the expan- 
 sion line is a smooth curve very nearly from the junction 
 with the steam line. 
 
ELECTRIC LIGHTING PLANTS. 59 
 
 This form of indicator diagram has been usually con- 
 sidered peculiar to the class of engine described in the pre- 
 ceding articles. In this case, the diagram is nearly as sharp 
 in the corners as these from a drop cut-off engine. The 
 range of expansion is from the beginning of the stroke to 
 about five-eighths. 
 
 There are four valves, as shown in the next Fig., which 
 is a section through the steam cylinder showing valve, ports, 
 and general construction. The two valves at the upper side 
 of the cylinder are the steam valves; the lower are the 
 exhaust valves. This section is, however, horizontal, the 
 valves being set on their edges at either side of the cylinder. 
 The exhaust valves are so placed as to drain the cylinder of 
 any water that may have entered with the steam, or may 
 have been produced by internal condensation. Both sets of 
 valves are so made, and set, as to be well balanced, and 
 so as to be capable of having the wear taken up when it 
 occurs. The steam valves are provided with packing 
 plates, which are adjustable by hand, to make them steam 
 tight, as well as to secure a perfect balance. Each valve 
 is placed in a separate valve-chest, and can be independently 
 adjusted. Each valve opens four ports; each is so set, that 
 it is actuated by a rod in the line of its own centre; and all 
 are thus rendered but little liable to either wear or leakage. 
 
 The rock-shaft arm on the intermediate rock-shaft, 
 seen in the large Fig. between the eccentric and the 
 steam valve stem, assists in securing the quick opening and 
 closing motion essential to a satisfactory distribution of 
 the steam. 
 
 The features which have now been described, are not 
 
60 STEAM ENGINES FOR 
 
 necessarily distinctive of a "high speed engine." A posi- 
 tive motion valve-gear, and a good steam distribution, are 
 desirable in such engines, and the first point is, in fast run- 
 ning machines, an essential requisite; but the Allen engine, 
 so far as it has been described, may be as well considered 
 a slow as a fast engine. There are some details, to which 
 r ve are now to turn our attention, which are essentially and 
 peculiarly characteristic of the class to which this machine 
 is assigned. Among these points are the strength and rig- 
 idity of parts which distinguish such engines; the great 
 nicety of fitting; the excellence of all material in every 
 part exposed to the straining action of inertia, and the 
 minor but yet important modifications of details to adapt 
 them to service in a machine, in which the slightest play in 
 joints or bearings will be certain to make trouble. The 
 bed is of peculiar design and is enormously stiff and solid, 
 especially in those parts which take the stresses of the re- 
 ciprocating pieces. It is broad and deep, with the line of 
 thrust of piston rod carried close to its surface between the 
 guides, and with a box form which gives great resistance to 
 forces tending to twist it. 
 
 The steam cylinder is secured to the bed by the end, a 
 construction adopted by Corliss many years ago, and one 
 which gives all desirable strength, with freedom from those 
 strains which come of connection of two large masses at 
 different and constantly varying temperatures. The whole 
 of its exposed surface is covered with lagging to prevent 
 loss of heat by radiation. The main journal boxes are 
 made in four pieces, and are set up by adjustable wedges, 
 so set as to avoid the springing of the shaft that is some- 
 
ELECTRIC LIGHTING PLANTS. 63 
 
 times found to occur with a less effective arrangement. 
 The main-shaft journals, and the journals of the crank-pins, 
 are made with especial care, skillfully ground to size and 
 form, and nicely finished before the engine is assembled. 
 The pin is always of " mild " steel, carefully case-hardened 
 to give it a surface that will wear well and will not " cut." 
 
 The provisions for lubrication in such engines are not 
 the least important of its details. The engine presents 
 some neat devices in this respect which we have not space 
 to describe. 
 
 One of the most remarkable and interesting of the fea- 
 tures, which especially adapt this engine to great speed of 
 rotation, and one, the developement of which, in its theory, 
 as well as in practice, is due to Mr. Porter, is a peculiar 
 adjustment of weight of moving parts to the equalization of 
 stresses on the line of journals between the piston and the 
 crank-shaft. When the steam is allowed to follow the pis- 
 ton only to some point early in the stroke, the ratio of 
 expansion being made, as is usual, between three and five, 
 the rapid fall of pressure, during expansion and up to the 
 end of the stroke, causes a very great variation in the effort 
 exerted upon the crank-pin and other journals. As the 
 maximum pressure occurs when the crank is passing the 
 centres, and while the work done usefully is, in consequence 
 of the slight travel of the piston, very little, and as, at the 
 same time, the considerable movement of the pin under this 
 pressure causes a considerable loss of work by friction, and 
 as it is advisable to secure a uniform effort producing rotation, 
 it is evident that it is desirable to find a method, if possible, of 
 equalizing the pressure throughout the stroke without sacri- 
 
64 
 
 STEAM ENGINES FOR 
 
 ficing the advantages of expanding the steam. The action 
 of inertia in the moving parts is made by Mr. Porter the 
 means of securing this result. 
 
 At the beginning of the stroke, the inertia of the piston, 
 its rod, the crosshead, and to a certain extent the connect- 
 ing rod, all reciprocating parts, causes them to offer a cer- 
 tain resistance to the accelerated motion which they are 
 compelled to take up. This resistance becomes less and 
 less up to zero at half stroke, the point at which their velo- 
 city is a maximum. Passing this point, they are rapidly 
 retarded, and this same property of inertia causes them to 
 offer a resistance to retardation, which resistance now is felt 
 as an impelling force at the crank-pin. Thus, the effect of 
 the presence of these heavy masses in the line of connec- 
 tion, produces a reduction of pressure upon the pin at the 
 commencement, and an increase of pressure at the end of 
 stroke. But, in consequence of the varying action of the 
 steam producing an excess of pressure at the beginning, 
 and a deficiency of pressure at the end of stroke, we may 
 combine these two effects, and the result is a comparatively 
 uniform load upon the crank-pin throughout the stroke. 
 
 This compensation is capable of being, in many cases, 
 very nicely adjusted by properly proportioning the weight 
 of the reciprocating parts. As engines are usually propor- 
 tioned with a view to strength of parts simply, the piston, 
 crossheads, and rods are too light to be of much service in 
 this way. Mr. Porter adopted the plan of making his pis- 
 ton and crosshead of such weight that the equalization of 
 pressures should be the most complete possible, and this 
 involved making them decidedly heavier than they are made 
 

 ELECTRIC LIGHTING PLANTS. 6 5 
 
 in common practice, even when his engines were driven up 
 to a speed which had never been before attempted in sta- 
 tionary engine practice. It is evident, however, that at some 
 higher speed, the weights of these parts, as proportioned 
 for strength simply, would be sufficient to give this desir- 
 able adjustment of the load on the crank-pin. There Is no 
 reason to suppose that this, which would seem to be a 
 natural speed of the steam engine, may not be at some 
 future time attained. 
 
 An interesting fact in this connection, is that Mr. Porter, 
 although not professionally a mathematician, or educated 
 as an engineer, first worked out the relations of these forces 
 by a simple process, and applied his results to his practice, 
 and that, subsequently, at his request, a distinguished hia- 
 thematician, Dr. Barnard, President of Columbia College, 
 attacked the problem by the methods of the higher analysis, 
 and revealed the laws involved, and verified completely the 
 work of the engineer. 
 
 The large engraving on page 49, represents one of three 
 pairs of engines in use at the Willimantic Linen Company's 
 mill. They are nj^ inches in diameter of cylinder, and 16 
 inches stroke of piston; they make 350 revolutions per 
 minute. This is not considered a high speed for these 
 engines, however. A considerable number of these engines 
 have been used in the electric lighting service of large cities, 
 to which service they were the first to be adopted for driv- 
 ing large dynamos directly connected. Under some con- 
 ditions, it is found that the weighted governor is too sensi- 
 tive, or too much affected by inertia, to give perfect regula- 
 tion. For such cases, Mr. Porter has designed an isochronal 
 governor, which is free from this cause of variation. 
 
66 STEAM ENGINES FOR 
 
 Engines of this class have many advantages, consequent 
 upon their high speed; they are, other things being equal, 
 more economical in the use of steam; they can be given a 
 very much smaller fly-wheel; they have, in consequence of 
 the enormously reduced weight of wheel, less friction; they 
 are more easily held to their speed by the governor; they 
 are less subject to variation of speed between beginning and 
 end of any one stroke; and they are usually less trouble- 
 some and expensive to connect to the load than slow run- 
 ning engines. These advantages are common to all classes 
 of engines, as they are driven up to high speeds; the class 
 here considered is simply better fitted to realize these 
 advantages than the older forms of engines, because they 
 are especially designed for high speed. The objection to 
 the "high speed engine, " is the increased risk of wear, and 
 of accident due to their rapid motion, and especially the 
 risk, that when accidents do occur, as they will now and 
 then in the best regulated establishments, they may be 
 vastly more serious than with engines working at ordinary 
 speeds. The object of the precautions which are taken by 
 builders. of fast engines, are all directed to meeting this 
 contingency, and to making their machines safe against 
 accident. These precautions are seen to be the strengthen- 
 ing, and especially the stiffening, of all the parts exposed to 
 the stresses due to the action of inertia in the reciprocating 
 pieces; the adjustment of all parts to each other in such a 
 manner as to avoid spring; the use of the best material; 
 an effective system of lubrication; and the securing of the 
 most perfect workmanship. 
 
 Watt once congratulated himself that he was able to get 
 
i 
 
 Pair of Porter-Allen Ei 
 
ELECTRIC LIGHTING PLANTS. 69 
 
 a steam cylinder that only lacked three-eighths of an inch 
 of being truly cylindrical; the builder of the "high speed 
 engine " of to-day works to the thousandth of an inch, in 
 longitudinal measurements, and gets his cylindrical journals 
 exact to the twenty thousandth, perhaps to the fifty thou- 
 sandth of an inch, a quantity which can be detected by a 
 good workman. The contrast illustrates well the progress 
 of a century in accuracy of workmanship where nicety is 
 required. Such nicety, only, can make a fast running en- 
 gine safe; such accuracy does make it safe, and such 
 engines now do their work uninterruptedly, year in and year 
 out, and are found to require no more than that ordinary 
 care which all engines are expected to receive. 
 
 A Porter-Allen engine, from the " Southwark Foundry/' 
 supplied power to the Weston, Edison, and the Thomson- 
 Houston Electric Light Companies at the Railway Exhibi- 
 tion at Chicago, May and June, 1883. 
 
 THE "BUCKEYE " AND " HARTFORD " ENGINES. 
 
 I ^HE engine last described was a long time alone in the 
 -*- field as a "high-speed engine." The principle rep- 
 resented by its designers was recognized as correct by every 
 intelligent engineer, and it was admitted that the fast engine, 
 other things being equal, would prove the most economical 
 in its expenditure of heat, as well as in its efficiency as a 
 machine subject to friction. But builders were not able to 
 bring themselves to accept what seemed to them the risks 
 incident to high speeds. The pioneer in this new field was 
 not altogether successful for a time, and it seemed to be 
 
7o STEAM ENGINES FOR 
 
 certain at one time, that the engine, despite the pluck, the 
 persistence, and the skill of its indefatigable promoter, must 
 retire from the market. But no discouragement could quite 
 destroy confidence in this engine, which had become the 
 embodiment of the most recent phase of progress. Grad- 
 ually, one difficulty after another was overcome; parts were 
 strengthened and given satisfactory proportions; the mate- 
 rials were improved and the workmanship of the machine 
 was made as nearly perfect as the best tools, handled by the 
 best workmen, could make it. A little gain was seen each 
 year, and, after a time, it was seen that the new class of 
 steam engine had "come to stay." 
 
 One of the first engines to come into the field after this 
 period of doubt had closed was built by an enterprising firm of 
 Western manufacturers. This was the " Buckeye Engine," 
 designed by Mr. J. W. Thompson, and built by the Buckeye 
 Engine Co., at Salem, Ohio. The engine did not start as a 
 radical competitor of the pioneer engine; but it was from 
 the beginning, a moderately high-speed engine. It was 
 fitted with a positive motion " automatic " valve-gear and a 
 balanced valve, and had a stability and an excellence of 
 workmanship that made it safe at fast speeds ; while the 
 peculiarities of its construction were such as gave it a very 
 high place as an economical machine. It was capable of 
 meeting in competition the best engines of the day. 
 
 The form given the larger sizes of this engine is seen 
 in the preceding Fig. The general arrangement is not 
 essentially different from that of the Corliss engine, which 
 has been described in earlier articles. 
 
 The cylinder is carried on a pedestal, as is the latter; 
 

 ELECTRIC LIGHTING PLANTS. 71 
 
 the frame consists of a girder uniting the cylinder and the 
 main pillow block and carrying the guides; the crank-shaft 
 end is carried by another pillow block. The main frame 
 is, however, supported by a strut which is now usually seen 
 in other engines, and which takes the load tending to spring 
 the girder under the guides. The construction of the cylin- 
 der, and the arrangement of the valves, is shown in the 
 next Fig. 
 
 The live steam is taken into the steam-chest at A, passes 
 through the passage, a, a, through the openings, D, JD, into 
 the box-shaped valve, B y F, and thence through the ports, 
 b y b t into the cylinder, as the ports in the cylinder are alter- 
 nately brought opposite those in the valve. The cut-off 
 valve is formed of two sliding plates, C y c, connected by 
 rods, C\ and sliding on seats formed on the inner, or work- 
 ing, side of the main valve, so as to cover the main steam 
 ports alternately, and at times which are determinable by 
 the governor. The stem, g, driving this valve, passes 
 through the main valve stem, which is made hollow for that 
 purpose. The cut shows the steam entering the cylinder 
 at the left, and the cut-off valve just beginning to slide over 
 the port, while the exhaust is taking place at the right, past 
 the end of the main valve, through the chest, and around to 
 the exhaust pipe seen partly dotted at F. At e, e y are seen 
 two "relief chambers," which receive live steam from the 
 steam valve through holes,/,/, and thus balance the valve 
 at a time when the pressure on the seat caused by the then 
 excessive area of the balance openings, Z>, d (which open- 
 ings must be made sufficient in area to produce a slight 
 pressure of the valve on its seat when the tendency to lift 
 
72 STEAM ENGINES FOR 
 
 the valve from its seat is greatest), is overbalanced. These 
 holes only fill when this relief is needed. The equilibrium 
 rings, £), d y seal the joint between the valve and the dia- 
 phragm separating the steam-chest, a, a, from the exhaust- 
 chest F. 
 
 The governor is of a type that has not been seen in the 
 engines previously described. It is shown in the following 
 illustration, page 68. 
 
 In the common " fly-ball governor,' ' the two balls revolve 
 about a vertical spindle, to which they are attached by a 
 pair of arms in such a manner that they may take any posi- 
 tion that the resultant action of gravity, centrifugal force, 
 and the pull on the supporting arms may give them. A 
 defect common to all governors of this class is that the 
 force tending to pull the balls downward is perfectly uni- 
 form. Gravity never changes at any one place. The posi- 
 tion taken by the balls, at any fixed speed of engine, is 
 always the same; the connection of the balls with the regu- 
 lating mechanism, is one which always preserves a fixed rela- 
 tion between the position of the governor balls and the posi- 
 tion of the regulating apparatus. Thus it happens that the 
 engine can never be kept precisely at speed, unless the speed 
 is such as will give the governor exactly its normal position 
 and, at the same time, such that the valves shall supply just 
 the normal quantity of steam to the engine. With reduced 
 steam pressure, the engine drops to a slightly lower speed, 
 and runs at that speed instead of the proper number of 
 revolutions; when the load decreases, the engine runs at a 
 little higher speed than is intended; and no method of 
 attaching that form of governor can give absolutely uni- 
 
en 
 
 W 
 > 
 .-J 
 < 
 > 
 
 w 
 
 Q 
 g 
 
 u 
 
 O 
 
 o 
 
 H 
 U 
 
 w 
 
 CO 
 
ELECTRIC LIGHTING PLANTS, 75 
 
 form speed. If, however, we can substitute for the action 
 of gravity, a force which can be made to vary with change 
 in the position of the balls, in such a way that the variation in 
 the opening of the throttle, or in position of the point of 
 cut-off, shall go on until the engine comes to speed, irre- 
 spective of all other conditions, we shall have what is known 
 as an "isochronous" governor, and shall be able to get the 
 correct speed, whatever changes occur in steam pressure or 
 in load, provided that there is steam enough to drive the 
 load at speed with the least expansion for which the engine 
 is designed. Such an adjustment can be made by substitut- 
 ing the tension of a spring, properly set, for the action of 
 gravity. The form of governor here illustrated is, or can 
 be made to be, of this class. It simply requires that the 
 spring tension shall be given a certain easily determined 
 relation to the effort of centrifugal force. 
 
 A governor of this character, when well made and 
 adjusted, will open the throttle valve, or will increase the 
 ratio of expansion, as the steam pressure diminishes or as the 
 load is increased, and will continue to move in the proper direc- 
 tion, indefinitely, or until the machine comes to speed, or 
 until'the engine is doing all that it can do. In the gov- 
 ernor here used, two levers are set on either side the crank- 
 shaft, in a frame or a pulley to which they are pivoted at 
 b, b. These rods carry weights, A, A y which may be ad- 
 justed to any desired position by means of the bolts seen 
 in the cut. The outer end of each rod is linked to the 
 loose eccentric, C, C, by the rods, B, B y and is controlled 
 by the springs, F, F y which resist the effort of centrifugal 
 force tending to throw the weights outward. As the weights 
 
76 STEAM ENGINES FOR 
 
 swing outward or inward, as the one or the other of the two 
 opposing forces predominates, the eccentric is turned on 
 the shaft in such a manner as to give the valves that motion 
 which is necessary to produce the proper distribution of steam 
 
 Governor. 
 to bring the engine to its speed. The adjustment of this 
 regulator to its work is easily obtained by the shifting of 
 the weights along the levers, or by increasing or diminishing 
 their amount, as is found necessary. 
 
Buckeye Automatic Engine. 
 
ELECTRIC LIGHTING PLANTS. 77 
 
 This governor is adjusted for an engine moving in the 
 direction of the arrow. To adapt it to an opposite motion, 
 the pins, b y b y are shifted to the other set of arms which are 
 shown having bosses for their reception. Wooden buffers 
 check the governor at the extremity of its range of motion. 
 
 The range of expansion, as determined by the governor 
 in this engine, is from the beginning up to two-thirds 
 stroke. 
 
 The engine has many interesting peculiarities of con- 
 struction, in its details, which space will not permit us to 
 consider. 
 
 The Hartford Engineering Company, who are build- 
 ing this style of engine, make a form of bed which is somewhat 
 similar to that designed by the makers of the Porter- Allen 
 engine, but which is particularly solid and graceful in ap- 
 pearance. It is seen on the opposite page.* This 
 firm, as well as the original makers of engines built under 
 Thompson's patents, endeavor to secure in their engines, 
 great weight in the parts in which solidity is important, 
 such large area of bearing surfaces as is essential in these 
 engines, moderately high-speed of piston and of rotation, a 
 steam pressure, usually of about 80 pounds per square 
 inch, and adopt a ratio of expansion for their non-con- 
 densing engines, of from four to five. Their table of 
 powers of their standard sizes is based upon estimates for 
 steam at 80 pounds and a cut-off at one-fourth. In con- 
 struction, these engines are carefully made with all joints 
 
 * The first designer to carry the line of the steam cylinder along the surface 
 of a "box-bed," and thus to secure maximum vertical and horizontal stiffness 
 in this manner, so far as the knowledge of the writer extends, was Dr. E. D. 
 Leavitt, Jr., who made such an arrangement in engines, in the design of which 
 the writer assisted, as early as 1860. 
 
78 STEAM ENGINES FOR 
 
 scraped, and all pins, and all journals also, ground with 
 scrupulous care. 
 
 The method of regulation is, as has been seen, quite 
 different from that practiced by the older standard makers. 
 It is subject to the objection, that as the regulator has 
 thrown upon it the duty of altering the position of the 
 eccentric, the load so brought upon it may make it less sen- 
 sitive and less effective in regulating the speed. This con^ 
 elusion, which is that usually held by the older engineers 
 in the profession, seems to be contrary to the fact; although, 
 when comparing the older kinds of engines, it is fully sus- 
 tained by the superior regulation of the engines of the u au- 
 tomatic " class. The fact, now familiar to every engineer 
 accustomed to the management of electric lighting ma- 
 chinery, that engines having regulators of the class to which 
 that under consideration belongs are capable of giving a 
 good regulation, even when directly connected to the dy- 
 namo, is sufficient proof that such a system of regulation 
 may be able to do perfectly satisfactory work. The fric- 
 tional resistance of the system, while in motion, is not a 
 matter of importance; as in any system in movement, and 
 subject to jar, the friction is practically eliminated and 
 every part assumes the position that it would take in a sim- 
 ilar system free from friction. The action of the resistance 
 of the valve, so far as it is transmitted to the regulator, 
 probably acts to hold the regulator fast during the period 
 of its action, leaving it free to move into any new position, 
 corresponding to the speed of the engine at the instant, 
 without hindrance during the remainder of the time. 
 
 All of these fast-running engines will be seen to have 
 
ELECTRIC LIGHTING PLANTS. 
 
 shorter strokes of piston than is customary with the earlier 
 types. One reason which has guided their designers to this 
 proportion is that the loss by internal condensation becomes 
 less as the steam is given less time to discharge its heat, and 
 hence high-speed of rotation and short strokes are adopted. 
 The best proportion of stroke to diameter of piston, the 
 number of revolutions in the unit of time being fixed, is easily 
 ascertained by a very simple investigation. It is found to 
 be two to one. This is about the proportion generally 
 adopted in these engines. Many engines are, however, given 
 a ratio of i 1-2 to 1. The shorter stroke has the great ad- 
 ditional advantage, the speed of piston being the same, of 
 giving a less costly engine to build. The proportion is 
 sometimes dictated partly by the character of the work to 
 be done; thus, in driving the dynamo directly, the velocity 
 of rotation must be very great and a short stroke becomes 
 advisable — the shorter as the speed is higher. In such 
 cases, therefore, engines are often made with even shorter 
 strokes than considerations of "efficiency" alone, would 
 dictate. 
 
 Reviewing the construction of this engine, it is seen that 
 it is distinguished from those which have been already de- 
 scribed, by its peculiar balanced valve which can be pro- 
 portioned to take any desired part of the steam pressure, 
 leaving, if properly adjusted, just enough on the valve to 
 hold it with certainty to its seat and to secure a little wear 
 to give bearing and fit between valve and seat, that this 
 valve is arranged to take steam through, and to deliver 
 steam outside, the shell; that it has a system of perfectly 
 flat wearing surfaces, and a positive movement of in- 
 
82 STEAM ENGINES FOR 
 
 variable extent, and thus is not liable to the formation 
 of shoulders on seat or valve; that its clearance is so 
 small that it is easy to counteract any ill effect, ordi- 
 narily due to that cause, by moderate compression; that it 
 has two ports and thus possesses such advantages as may 
 be claimed for that arrangement; that the governor is driven 
 by a positive connection with the shaft on which it is set; 
 that, as the cut-off is adjusted by the motion of an eccen- 
 tric, the ratio of expansion is the same at both ends of the 
 cylinder and that it possesses the advantage, common to all 
 engines having a positive motion valve-gear, of being unre- 
 stricted in speed. 
 
 Many of these engines are already in use driving electric 
 lighting machinery. 
 
 THE CUMMER ENGINE. 
 
 A LL of the class of engines now under consideration 
 ^ ■*- have been seen to differ radically from the engines 
 previously described (as not well fitted for direct connec- 
 tion to the dynamo), and to have a number of character- 
 istic points in common which especially fit them for use in 
 direct connection. This latter class of engines, however, 
 exhibit some differences among themselves which are im- 
 portant and very interesting to the engineer and the user 
 of steam power. 
 
 The engine last described will have been seen to differ, 
 in a very notable way, from that which immediately pre- 
 ceded it. The latter had a system of valves that differed 
 from the former no less radically than did its system of 
 regulation. We have now to study an engine which re- 
 
The Cummer Engine. "C' 
 
ELECTRIC LIGHTING PLANTS. 85 
 
 sembles the last in its general features — the use of a cut-off 
 valve riding on a seat formed upon or in the single main 
 valve, a system" original in principle with Meyer, an engineer 
 well-known, years ago, in Europe, and the use of the pecu- 
 liar form of governor which adapts itself to a position on 
 a horizontal or on an upright shaft with equal facility. 
 This engine, however, has some curiously interesting and 
 ingeniously contrived points of construction which, as well 
 as its performance, make it well worthy of attention. This, 
 the "Cummer Engine," is illustrated in the engravings to 
 be described below. 
 
 The Cummer Engine Company makes a number of dif- 
 ferent forms of engine, using various kinds of valve-gear 
 and different forms of regulator and of engine frame ; but 
 the style with which we are here principally concerned is 
 that which is best adapted to driving a load at high speed 
 with great economy and with the most perfect regularity. 
 
 The general form of the engine, as shown in the Fig., on 
 page 74, is very similar to that of engines already described. 
 It has the " girder" frame, or bed, is well supported at each 
 end, has a firm and substantial connection in the line of 
 thrust and pull between cylinder and crank-shaft, and pro- 
 visions for lubrication especially fitted to give safety at high 
 rates of speed. A modified form of bed is seen in the next 
 illustration, in which one of the engines designed for the 
 highest safe speeds is shown. In this engine, the frame is 
 made with a pedestal cast upon it directly under the guides 
 and extending under the whole length traveled by the 
 crosshead, thus giving absolute stability at the point at which 
 cross strains are most severe and most productive of injury. 
 
86 
 
 STEAM ENGINES FOR 
 
 The cylinder overhangs, unsupported, at the back end of 
 the frame. No support is there needed, however, as no 
 appreciable vertical stress occurs there. This engine has 
 the same valve and gear, and the same form of governor as 
 is used in the preceding style of machine. In this latter 
 form of engine, the crank is replaced by a disc, an arrange- 
 ment which enables the builder to effect a more perfect bal- 
 ancing of the reciprocating parts than can well be obtained 
 with the ordinary form of crank. The rigidity of this form 
 of engine is seen to be as essential a feature as in those 
 which have been previously described. The box girder 
 gives this stiffness in a very satisfactory manner. 
 
 The Cummer Engine. "B 
 
 The main guides are flat, and are fitted with removable 
 faces which can be readily repaired or replaced, when worn 
 or "cut," at small cost of time and money. The cros.ihead 
 is a compact, strong casting, having bearing surfaces extend- 
 ing well out under the pin, and under the piston-rod socket, 
 as well, and it is therefore not likely to cause those awkward 
 accidents, due to springing the piston rod at this connec- 
 
ELECTRIC LIGHTING PLANTS. 
 
 87 
 
 tion, which have proved so costly in less well designed en- 
 gines. The gibs which take the wear are removable and 
 adjustable. The main bearing is fitted with four-part boxes 
 of babbitted cast iron, the side pieces so arranged that they 
 may be set out to a bearing as they wear. All the details 
 are in accordance with standard practice in this class of 
 engines, and description is not called for here. It may be 
 safely assumed that this is the case in any successful engine, 
 as good workmanship, the best materials, and a strong sys- 
 tem of connections, are essential pre-requisites to even the 
 beginning of success. 
 
 Cylinder; Steam Valves. 
 
 The valves and the valve-gear of the Cummer engine, 
 as has been stated, belong to the " Meyer system " and con- 
 sist of a main valve with the cut-off valve riding on the 
 back of the main. There is this difference, however, be- 
 tween the gear of this engine and others of the same gen- 
 eral system : that here we find a separate system of exhaust 
 
STEAM ENGINES FOR 
 
 valves which are worked independently of the steam valves, 
 and thus leave the induction and eduction motions entirely- 
 free to be adjusted as the designer, the constructor, and 
 the user, may desire. The preceding engraving shows the 
 disposition of the valves in the cylinder casting, and the 
 larger cuts exhibit the method of driving them. The sec- 
 tion of the cylinder, above, is made horizontally through 
 the steam valve chest, and shows the main valve in section, 
 with the cut-off valve riding upon it. At the left is a section 
 so made as to exhibit the exhaust valve seat. This is made 
 removable. It will be noticed that the valves are of what 
 the engineer calls the " gridiron " pattern. They are so 
 made, with their several ports, to obtain a free opening with 
 small movement and reduced friction of the valve. The 
 writer has found this device a decidedly advantageous one, 
 and it has been used by some of the most successful design- 
 ing engineers of his acquaintance. The more numerous 
 the ports, the less the travel required for the valve, the 
 smaller the steam chest space demanded, and the less the 
 load on valve-gear and governor, usually. 
 
 The next illustration represents the same parts of the 
 engine as seen from the side, with valve-chest bonnet re- 
 moved at one end, and a section made opposite the supply 
 pipe to show the passages and valve-rods. These rods are 
 driven by the main eccentric, the steam valves directly, and 
 the exhaust through a rock-shaft. The cut-off valve is 
 driven by a separate eccentric, as in the preceding form of 
 engine, and this eccentric, like the preceding, is adjustable 
 in position on the shaft by the governor. The engine is 
 thus made " automatic " in its adjustment of the point of 
 
ELECTRIC LIGHTING PLANTS. 
 
 89 
 
 cut-off, and in regulation. Separate valves are seen at each 
 end of the cylinder, and the "clearance" and " dead space" 
 is thus reduced to a minimum. This last provision makes 
 it possible to " cushion" the exhaust steam up to boiler pres- 
 sure on the return stroke, and thus to secure a minimum 
 waste by condensation on the opening of the steam valve 
 for the succeeding stroke. Cushioning is not here limited by 
 the steam side. The construction of the connecting rod, 
 and the method of connection, are such that the wear of jour- 
 
 o; 10; \o 
 
 9) — (9. 
 
 O: CO 
 
 ; i 
 
 01 r:^6>jz±vo 
 
 rooB 
 
 JT« L 
 
 Cylinder; Elevation and Section. 
 
 nals and bearings may be taken up, in any case, without 
 altering, to any observable extent, the position of the piston 
 in the cylinder, and this permits small cylinder clearance, 
 also. For the reason above given, the port spaces are 
 made no larger than is necessary. 
 
 A comparison of this engine with others of its class will 
 
90 STEAM ENGINES FOR 
 
 exhibit one very peculiar feature, in which this engine 
 stands entirely alone. The governor is carried on a " gov- 
 ernor shaft " which is geared to the main shaft, and which 
 has no other office than that of carrying the governor and 
 the eccentrics. It is evident that so radical a departure 
 from standard design must have been caused by the possi- 
 bility, actual or presumed, of thus attaining some very im- 
 portant result. A little study shows plainly what this 
 supposed advantage must be. 
 
 The necessity of providing for efficient performance at 
 high speeds of rotation has been seen to have compelled the 
 adoption of a positive motion valve-gear; the adoption of 
 this gear led to the use of a powerful form of governor, di- 
 rectly attached to the cut-off eccentric; this, in turn, compels 
 the use of revolving weights, turning in orbits lying in the ver- 
 tical plane; this last feature, in turn, again made it necessary, 
 apparently, to place the governor on the main shaft, and to meet 
 the effort of centrifugal force by a counterbalancing action, 
 which could then only be obtained by the use of steel 
 springs set in the casings of the governor. But the use of 
 springs is considered by many engineers to be so objec- 
 tionable, that they would submit to some expense and incon- 
 venience to avoid their application, if possible. The objec- 
 tions are that they are liable to changes of tension and of 
 length while at wbrk, that they never have a definite and 
 calculable strength, that they are liable to break in most 
 unaccountable ways, and at most unreasonable and unex- 
 pected times, and that the adjustment of a balance between 
 the two equilibrating forces is often difficult and almost always 
 unsatisfactory. These ob j ections undoubtedly do to a certain 
 
ELECTRIC LIGHTING PLANTS. 
 
 9* 
 
 extent exist; but they as certainly are not as serious as is 
 often supposed. The writer has had a long experience 
 
 The Cummer Governor Section. 
 
 in this direction, both in the use and in the observation 
 of the steel spring for a wide variety of applications, 
 and has never yet seen reason to condemn them unre- 
 
STEAM ENGINES FOR 
 
 servedly. The principal objection which can be urged 
 against the governor of this class, as usually adopted for the 
 kind of engine now under consideration, is probably the 
 fact that it cannot be reached while the engine is in opera- 
 tion, and that change of speed is thus made impossible 
 except by stopping the machine and making changes in the 
 adjustment of the springs, then trying the speed again, and 
 again stopping to adjust, until the desired speed is exactly 
 attained, which disadvantage is shared by the older arrange- 
 ment of governor. 
 
 The form of the Cummer governor, which has been de- 
 signed to evade these objections to the use of springs, and 
 to secure certain special advantages, is shown in the above 
 illustration and in that which follows. As has been seen, 
 when studying the design of the engine as a whole, the 
 governor of the Cummer engine is of the same general type 
 as that of the engine last described; but it is mounted upon 
 a shaft, separate from, and driven by gearing from, the main 
 shaft. The governor shaft also carries the eccentrics, one 
 of which is loose on the shaft and is controlled, as to position, 
 by links from the weights of the governor as usual. The 
 governor is thus enabled to shift the eccentric forward or 
 backward and thus by changing its lead, to determine the 
 movement of the cut-off valve and the ratio of expansion. 
 
 There is nothing specially remarkable about this part of 
 the arrangement. The position of the weights is seen to be 
 determined, however, by a system of bell-crank levers which 
 connect the middle point of each weight with a vertical rod 
 and chain under the engine bed, and on this rod is carried 
 a set of weights which may be easily reached when the 
 

 ELECTRIC LIGHTING PLANTS. 
 
 93 
 
 engine is running. The bell-cranks within the governor 
 casing, move a rod which passes along the centre line of 
 the governor shaft and emerges at the left. This rod en- 
 gages a large bell-crank at the end of the shaft, through 
 which the load suspended under the engine is sustained. 
 But one spring, and that a small one, is seen in the whole 
 system. The centrifugal action of the governor weights, 
 when at the inner limit of their range, is met by the weights 
 on the scale pan, and the spring is only required to meet 
 
 The Cummer Governor. 
 
 the additional action of the governor weights when they 
 fly outward, as the engine increases speed. The more nearly 
 an equilibrium is maintained between the action of the 
 flying weights and the balancing load, at the proper speed 
 of engine and at all possible positions of the governor, the 
 more perfectly "isochronous" does the governor become, 
 and the more exactly will the engine hold its speed, under 
 all variations of steam pressure and of load. With this 
 
94 STEAM ENGINES FOR 
 
 governor, the weights on the pan can be increased or 
 diminished at any moment, and to any desired amount, 
 whether the engine is in motion or at rest; the isochronous 
 adjustment can be effected as nearly as desired, and the 
 speed of engine may, at any moment be altered, much or little 
 as may be advisable. 
 
 This accessibility of the governor, and the disuse of 
 heavy springs to control it, are the principal advantages of 
 this form of governor. It has also some incidental advant- 
 ages which are worthy of notice, although of less import- 
 ance. The governor shaft is comparatively small; this per- 
 mits the use of very small eccentrics; this reduces friction 
 and load on the valve mechanism, and this, in turn, adds a 
 little to the efficiency of the engine, as a compensation for 
 the introduction of an additional shaft. The one spring 
 used here is smaller than that needed for other governors 
 of the same class, and is relieved from tension entirely at 
 frequent intervals, and the periods of " rest " thus given it 
 are likely to insure an increase in its longevity which may 
 prove to be a point in its favor worth mentioning. It may 
 sometimes, although certainly not frequently, occur that an 
 engine may be required to work, at different times, at cer- 
 tain different, but fixed, speeds. In such a case, it is easy, 
 with this engine, to find a set of weights which when in 
 place, will give each one of these fixed speeds; the engine 
 can then be, at any instant, brought exactly to either speed 
 by hanging on the scale pan the right weight for the speed. 
 The several weights can be kept at hand for use as required. 
 Such an arrangement may be sometimes especially useful in 
 electric lighting. 
 
ELECTRIC LIGHTING PLANTS. 95 
 
 Several styles of the Cummer engine, other than those 
 which have been described, are built for the market. Those 
 which have been here illustrated are, however, especially 
 fitted for such work as is the subject of this article. Both 
 of the forms which have been described are well adapted 
 to use in electric lighting plants, and are proportioned for 
 high speeds; they are designed for nice regulation and are 
 likely to prove durable, economical, and otherwise satisfac- 
 tory motors. They are intended for steam pressures of 90 
 or 100 pounds per square inch, and their rated powers are 
 based upon an assumed piston speed of about 400 times the 
 cube root of stroke, as nearly as it can well be reckoned by 
 the old method of James Watt — a speed more than three 
 times as great as was thought best in the time of that great 
 engineer. Even this speed is not to be considered remark- 
 ably great for engines designed and built, as are these, with 
 especial regard to the requirements of high-speed motors. 
 The steam pressures adopted are those generally regarded 
 by engineers as, on the whole, the best for ordinary pur- 
 poses, and are those beyond which the gain in economy by 
 further increase becomes rapidly less with even the best 
 engines. The point of cut-off is calculated, in estimates 
 of power, to be at from one-fourth to one-fifth stroke, and, 
 as a rule, nearer the first than the last figure. The best 
 ratio of expansion for any given case is to be determined by 
 a comparison of cost of fuel and steam supply with other 
 operating expenses, at the place of operation. 
 
 The engine above described has been used, in many cases, 
 to supply power for driving dynamos in electric lighting, 
 and has an excellent record in that field, as well as in cotton 
 
9 6 
 
 STEAM ENGINES EOR 
 
 and flouring mills, which demand the most perfect possible 
 regulation. 
 
 One of these engines (16x36), at the Cincinnati Exhi- 
 bition of 1883, was tested by the committee on electric 
 lighting apparatus and found to alter its speed but 2^ per 
 cent., when the whole load, 124 horse-power, was thrown on 
 or off; it varied one revolution per minute with a change 
 of steam pressure of from 90 down to 50 pounds. 
 
 The indicator cards, of which copies are given above 
 as taken from this engine, show the method of distribution of 
 steam in engines with positive motion valve-gears, such as 
 are here considered as fitted for direct connection with 
 large dynamos, and for high speed generally. The illustra- 
 tion exhibits a series of indicator diagrams taken from this 
 engine at points of cut-off varying from one-tenth to ^one- 
 third stroke. It is seen that the steam lines are as straight 
 as those of a drop cut-off engine, very nearly up to the point 
 at which the effect of closing the cut-off valve begins to ex- 
 hibit itself in the production of the expansion line. The 
 

 ELECTRIC LIGHTING PLANTS. 97 
 
 expansion curve is very nearly that obtained by laying down 
 the hyperbolic curve of Marriotte, and the exhaust is as 
 clean and prompt as need be desired ; the back-pressure 
 line closely follows the atmospheric line seen immediately 
 beneath it, and the compression line at the right hand end 
 of the card is quite as good as is often seen in the most per- 
 fectly proportioned engine with detachable valve. As the 
 steam follows further and further, the sharpness of the 
 corner between steam and expansion lines gradually be- 
 comes less, and the form of that part of the diagram ap- 
 proximates that found in the older forms of plain slide 
 valve engine. For the most generally desired ratios of ex- 
 pansion, however, the form of the curve is satisfactory, and 
 it is evident that the adoption of the positive motion type 
 of valve-gear does not introduce any very serious loss of 
 efficiency in this respect. 
 
 THE STRAIGHT LINE ENGINE. 
 
 73 EVIEWING what has been said in this section of 
 -^^- engines capable of direct connection to the dynamo, 
 it will be noted that the engines which have now been de- 
 scribed have belonged to two classes, differing from each 
 other in two very important respects. In the first, repre- 
 sented by the Porter- Allen engine, we find a form of engine 
 especially, and very ingeniously, designed for high speed of 
 rotation, fitted with four balanced valves, with the object of 
 securing minimum " dead space," and maximum economy 
 and ease of working, and controlled by a governor which 
 differs from the older form introduced by Watt, by several 
 
STEAM ENGINES FOR 
 
 useful modifications of design, and especially, by being 
 loaded in such a manner that its speed, and, consequently, 
 its power and sensitiveness in working, are greatly increased. 
 In the second class, we find a valve-gear of the Meyer type 
 driven directly by the eccentric, instead, as in the first 
 class, through a link, and regulated by a governor riding on 
 the main or the governor shaft, beside, and directly attached 
 to, the eccentric. The features essential to a " high speed " 
 engine are also embodied in the second, as well as in the 
 first, class of engine. 
 
 We now come to the examination of a third-class of high 
 speed engine, which differs as radically from the two pre- 
 ceeding as they from each other. In this new form of engine 
 we find but a single valve which does duty both as a dis- 
 tributing and as a cut-off valve. A form of engine belong- 
 ing to this class, with which the writer happens to be 
 familiar, is that known in the market as "The Straight 
 Line Engine. ,, 
 
 This engine, so far as it is novel, is the invention 
 of, and also is designed by, Professor John E. Sweet, form- 
 erly the superintendent of the workshops in which instruc- 
 tion in machine work was given in the Department of 
 Mechanical Engineering of Cornell University— a position 
 in which he became widely known as one of the most skilful 
 and ingenious mechanical engineers in the United States- 
 later a President of the American Society of Mechanical 
 Engineers. The first of these engines was built at Ithaca 
 for experimental purposes, by students under the instruction 
 of the designer. 
 
 The Straight Line Engine has many interesting and novel 
 
Straight Line Engine. 
 
ELECTRIC LIGHTING PLANTS. 
 
 points, which will bear much more extended study than they 
 can be given in the small space which can here be allowed 
 for the description of the engine. The problem, proposed 
 to himself by the inventor, was to design an engine which, 
 while consisting of the smallest possible number of parts, 
 should, nevertheless, be economical in its use of steam, 
 capable of the most perfect regulation attainable with any 
 known device, strong and stiff in every part subjected to the 
 working strains of an engine working at high speed, inex- 
 pensive in first cost, and durable as a simple engine can be. 
 
 This engine is shown in the accompanying illustration. 
 
 A vertical engine, which is shown at the end of the 
 article, is also designed for all powers ; there seems no 
 reason why it should not prove a good style for heavy work; 
 better in some respects, in fact, than the horizontal engine. 
 
 The engine takes its trade designation from its peculiar 
 form of frame, which is seen to consist of two perfectly 
 straight diverging struts extending from the end of the 
 cylinder directly to the two main bearings, thus carrying the 
 line of resistance to the pull and push of the connections 
 exactly along its own central line. No possible arrangement 
 could give greater stiffness with the same weight of material. 
 The whole structure is carried upon three points of support, 
 as is the practice with " surface plates," which must, if pos- 
 sible, have an absolutely definite and invariable system of 
 suports, to avoid the slightest danger of "spring." These 
 points are under the main bearings, and beneath the steam 
 cylinder. The two journals receive equal loads ; the crank- 
 pin is not subject to the deflecting forces met with where 
 a crank is overhung ; danger of unequal wear of journals, 
 
102 STEAM ENGINES FOR 
 
 and of springing the pin, is thus avoided very completely. 
 The fly-wheel is placed in twin-form between the main 
 bearings, and also serves as crank, thus making the best of 
 cranks as well as balance wheel. This position of the bal- 
 ance wheel is one of peculiar advantage. By its action at 
 this point, it intercepts heavy and objectionable stresses, 
 which, in other engines, are transmitted to the main shaft ; 
 and the reciprocal action of counterweights and equilibrat- 
 ing parts is thus only felt within a mass of metal, which can 
 resist them with perfect safety, and without their being felt 
 in the more sensitive parts of the machine. This arrange- 
 ment renders the main journal less subject to springing un- 
 der the loads transmitted through it. To secure better dis- 
 tribution of wear, the crank shaft is allowed some end-play. 
 This end-play, together with the carefully arranged system 
 of lubrication, are the best possible insurance against exces- 
 sive friction and wear. 
 
 The steam cylinder has the appearance of the cylinder 
 familiar to every one, as seen on ordinary plain slide-valve 
 engines. Its valve chest is placed at the end nearest the 
 crank, and the ports and passages are carried as in those 
 engines. The valve stems have no stuffing boxes, but pass 
 into the chest through unusually long and carefully fitted 
 holes, in a hub, made about five one-thousandths of an inch 
 larger than the rod inside the Babbitt metal bushing, 
 for a length of six diameters or more. The hub is 
 loose in the hole in the end of the valve chest, and is 
 packed at the ends by a washer fitted on a flat seat on the 
 inside. The piston-rod is similarly fitted. 
 
 The crosshead is a very long casting which overruns the 
 
ELECTRIC LIGHTING PLANTS. 105 
 
 guide at each end at every stroke, and thus is rendered safe 
 against wearing to a shoulder. A pin subject to recipro- 
 cating efforts in any part of an engine, whether it rotates, or 
 carries a rotating or a vibrating piece, is apt, in time, to 
 show wear on the two sides in line with the principal pull 
 or thrust, and to lose its cylindrical form. In this engine, 
 such wear is avoided at the crosshead pin, by cutting away 
 the surfaces, which do little or no work, and thus securing 
 overrunning surfaces, which are not subject to this distorted 
 wear to so great an extent. Many other minor points invite 
 attention, but they cannot be here considered. 
 
 The principal feature of this design, in connection with 
 that phase of its work which is of especial interest here, is 
 its valve-motion. The valve is a rectangular block, sliding 
 between the seat and acoverplate; is shown in the engraving. 
 Ports are cut through the coverplate, through the valve, 
 and through the seat into the steam and exhaust passages 
 in the cylinder casting, in the proper positions. These ports 
 are double at the ends of the valve, and a single port of 
 ample area is made through the middle of the valve. 
 
 The valve is what may be called a " piston valve " of 
 rectangular section, the space in which it slides having, 
 therefore, also a rectangular section, and permitting the use 
 of a detached coverplate, which, while sustaining the pressure 
 of steam that would otherwise come upon the valve, 
 and thus making it a balanced valve, nevertheless allows 
 any unusual pressure, occurring when the piston comes 
 back to the compression period of its cycle, to raise it, and 
 thus to permit the water which may have caused the pressure 
 to flow back, and thus relieve the cylinder, and obviate all 
 
io6 STEAM ENGINES FOR 
 
 danger of forcing out the heads. The principal feature of 
 this device is not new ; the writer handled such a balanced 
 valve on marine engines, rated at above 5,000 horse-power, 
 nearly twenty years ago, and found them, so far as his own 
 experience went, perfectly satisfactory. This new applica- 
 tion of the principle, however, embodies some new and 
 interesting points. The valve cover is sustained on loose 
 packing strips, which are free to close up upon the edges of 
 the valve, and to take up wear as it occurs. The form of 
 the plate, its domed top, is such as to give it great stiffness 
 against the superincumbent pressure, and thus to prevent 
 pressure on the valve itself in consequence of spring in the 
 plate, and the ports are so placed as to prevent the cutting 
 away of the faces and seats by the rushing currents of steam. 
 The valve and cylinder ports are not dressed out ; the 
 casting is made so accurately that these edges can be left as 
 they come out of the sand without loss of efficiency in the 
 working of the valve. 
 
 The valve is driven by an eccentric, the motion of which 
 is controlled by the governor, and the connection of which 
 with the valve is effected by the peculiar system of linking, 
 seen in the preceding illustration. The eccentric is so sus- 
 pended from the disc, to which it is attached, that it may 
 be thrown across the shaft by the action of the governor, in 
 such a manner as to give the effect of the once common 
 and well known " Dodd motion. " It is carried on a lever, 
 which is pivoted at one side of the shaft, while the governor 
 rod is attached at the opposite side. The singular positions 
 of the eccentric rod and the rockshaft arm enable the 
 alteration of the throw of the eccentric produced by 
 
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 W 
 
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 H 
 
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 c/2 
 
ELECTRIC LIGHTING PLANTS. 109 
 
 the governor, to be effected without alteration of the 
 lead of the valve, so that the steam may be admitted, at all 
 times, at the same point in the revolution of the engine. 
 This it does, since the line of the eccentric rod is, at the 
 commencement of stroke, in line with the lever on which the 
 eccentric is carried. 
 
 The governor is similar, in principle, to those which have 
 been described as used on the last type of engine. It con- 
 sists of a single weight, or ball, carried on the end of a lever 
 which is pivoted, near its middle point, on one of the arms 
 of the governor pulley, and connected to the spring, by 
 which it is held under control, by a link extending across 
 to the other side of the shaft to the end of the spring, which 
 is there secured to the rim of the pulley. The action of 
 the governor is substantially the same as that of those which 
 have been already described. When the speed decreases, 
 the tension of the spring, at the end of the weight lever, over- 
 comes the centrifugal effort of the ball, and the latter is 
 forced in toward the shaft, carrying with it the end of the 
 eccentric lever, and thus giving the valve greater throw, and 
 extending the period through which the steam follows the 
 piston, producing more power and bringing the engine up 
 to speed. The reverse change of speed of engine produces 
 the opposite action of eccentric and of valve motion, and 
 the cut-off is shortened, and the power of the engine is re- 
 duced to that needed to give the correct speed. As this 
 governor may be made as nearly isochronal as may be de- 
 sired, the approximation to correct speed may be made as 
 close as is consistent with the sensitiveness considered per- 
 missible. The use of a single eccentric and of a single gov- 
 
STEAM ENGINES FOR 
 
 ernor ball, and the general simplicity of this combination, 
 are especially pleasing to the engineer. They, however, 
 include the use of a single valve, and thus restrict the de- 
 signer, somewhat, in his adjustment of the steam distribu- 
 tion, a restriction which the more complicated forms of 
 valve-gear are constructed to avoid, as it is well understood 
 that the economy of the machine, in its use of steam, is to 
 a certain extent, dependent upon the method of distribution 
 of the steam entering, and of the exhaust leaving the cylin- 
 der. The main objection is the fact that the mean pressure 
 of the steam entering the cylinder up to the point of cut-off 
 is necessarily less with a single valve than with the gear in- 
 troduced by Sickles and Corliss, and their successors, and 
 which have been long standard, and which are admittedly 
 superior in this respect. Whether the more costly, but 
 more efficient gear shall be used, is to be determined partly 
 by the cost of fuel, and must be settled by the judgment of 
 an experienced engineer in each individual case. 
 
 The difference in this respect is not, however, as great 
 as has been by some engineers supposed, and the econom- 
 ical value of heavy compression is now becoming so well 
 understood, that the general impression in regard to this sys- 
 tem of valve motion is becoming considerably and rapidly 
 modified. What is lost by the drop of pressure between the 
 boiler and the piston, is partly compensated by the variable 
 and automatically adjusted compression obtained with this 
 kind of motion, as is well illustrated in the action of the 
 Stephenson link as used on the locomotive. With this 
 arrangement, there is also some loss at the exhaust period, 
 but not usually enough to be considered serious. As this 
 
ELECTRIC LIGHTING PLANTS. 113 
 
 particular engine is operated, this latter loss, and possibly, 
 to a slight extent, the former, are somewhat reduced by 
 setting the valve without lead, or even with " negative lead," 
 i. e. so that the engine does not take steam until the crank 
 has just passed the center, and the piston is starting on the 
 forward stroke. 
 
 The engine, as a whole, with all its important parts in 
 section, is shown in the above engraving. The unusual 
 quantity of material as compared with earlier practice in 
 older forms of engine, the excellent distribution of that 
 material, the small number of parts, the heavy crosshead, 
 the arrangement of fly wheels, and the form of valve are all 
 plainly seen, as well as the general arrangement and system 
 of connection. The rods and pins, and all running 
 parts, are made of steel ; journals are ground to perfect form 
 and polished, and the engine, when completed, is set up in 
 the shop and carefully tried before sending it out, as is 
 becoming the custom with good builders everywhere. The 
 designer has made a special effort to reduce friction to a 
 minimum, and has given the engine easy running piston and 
 crosshead, perfectly formed journals, and a valve gear and 
 governor, which are as nearly frictionless as those parts can 
 well be made. The growth of the engine into its present 
 shape, from the first crude sketches made in 1869, to the 
 finished engine and completed type of to-day, and especially 
 the gradual evolvement of the governor and valve gear from 
 the older forms, would be an interesting subject of study, 
 but it cannot here be undertaken. The survival of the fit- 
 test, among these devices, has led to the production of the 
 engine above described. 
 
 The Straight Line Engine has been frequently applied 
 
1 14 STEAM ENGINES FOR 
 
 to the driving of electric lighting apparatus. In Pen- 
 ney's arrangement of a station of 120 lights, the 
 connection of power to dynamo is effected through 
 friction clutches, which may, at any instant, be thrown 
 out or thrown in ; any two of the engines have ample 
 power to drive all three of the dynamos used, and a reserve 
 is thus supplied to be used in case of the necessity of 
 throwing off one engine for repairs. The current from 
 any one generator is capable of being switched into any 
 circuit, and all parts are accessible for examination and 
 repair. A novel device is that of placing the driving pulleys, 
 on the main line, on separate hollow shafts, independently 
 supported, to prevent the springing of the line shaft by 
 the pull of the main belts. The line shaft runs directly 
 through the jack shaft, carrying the driving pulley on 
 the line. 
 
 As this engine is adjusted, with large compression when 
 at regular speed doing the rated work, with negative lead on 
 the valve at that point, becoming positive lead at ^ cut-off, 
 it illustrates well the efficiency of the class. A 50 horse- 
 power engine, driving a 40 light dynamo, according to 
 the report of the manager at the station, ran at 219 revolu- 
 tions, and at 220 when 27 lights were thrown off. The 
 writer, testing one of these engines rated at thirty-five 
 horse-power, using a Prony brake to take up the 
 power, counted 233 revolutions, light, and 232, loaded 
 with above forty horse-power ; with lower steam, the 
 figures became 231 and 230. A well-balanced valve 
 and a nearly frictionless governor are the elements giving 
 success here. Every good engine, driving dynamos, is 
 
ELECTRIC LIGHTING PLANTS. 
 
 "5 
 
 expected to rival this, doubtless, but, doubtless many do 
 not. The single-valve engine can evidently, as is here 
 seen, be made, by a skilful engineer, to do excellent work. 
 
 Vertical Straight Line Engine. 
 
n6 STEAM ENGINES FOR 
 
 IV. 
 Engines Capable of Direct Connection. — [Continued?) 
 
 THE ARMINGTON AND SIMS ENGINE. 
 
 THE engine last described, and that to be here examined, 
 are the result of an attempt on the part of their design- 
 ers to secure a form of engine which should not only be so 
 proportioned and so arranged in the disposition of their 
 details that they maybe driven up to the speeds of rotation, 
 now so frequently found desirable, without excessive jar, 
 serious wear, or dangerous heating of journals, but which 
 should also be so simple in plan, so inexpensive in construc- 
 tion, and so easy of repair, that the cost of maintenance, 
 that great tax upon the proprietor of the average steam en- 
 gine, should be reduced to the lowest possible figure. 
 
 In these engines, the possibilities in the direction of in- 
 creasing speeds, are sought to be made the most of. Their 
 market is not only to be found in the domain of the electrical 
 generation of light, and electrical transmission of power, 
 but in older fields of work as well. The loss of power in 
 the "jack-shafts," or "first motion shafts," of mills and 
 workshops driven by the low-speed engines is an item of 
 no inconsiderable amount in many cases. The tendency 
 is now observable toward the adoption of the high-speed 
 engine, even where not quite as economical in the use of 
 steam, in direct connection with the main line of shafting, 
 through the intermediary of a single belt or pair of gears, 
 or even by directly attaching the crank-shaft of the engine 
 
ELECTRIC LIGHTING PLANTS. 119 
 
 to the main line by a coupling. Many flouring mills and 
 several rolling mills to the personal knowledge of the 
 author, have been operated in this way for some years, and 
 the system will probably become rapidly more general. 
 In this country, the use of gearing for such connections has 
 long been almost entirely superseded by the introduction of 
 belting. The smaller first cost, the diminished noise, the 
 lessened danger which accompanies their failure, and other 
 obvious advantages, have been found to far more than 
 counterbalance the cost of maintenance of the belt. By 
 thus connecting directly to the main line, also, the cost of 
 belting is greatly reduced. As the speed of shafting is 
 rarely less than 150, and seldom more than 250, revolutions 
 per minute, it is not difficult or objectionable to establish 
 this method of connection. The same advantages are then 
 derived that are experienced in the direct connection of 
 the engine to the dynamo-electric machine. The total first 
 cost of power is thus often reduced thirty and sometimes 
 50 per cent. As has been already intimated, there seems 
 to be no nearly reached natural limit to the increase of 
 engine speeds, except the practical limit of perfection of 
 workmanship and excellence of materials, which limit is 
 being constantly pushed farther and farther back, as the 
 demands upon our engineers and mechanics are more and 
 more exacting. President Westmacott, of the British In- 
 stitution of Mechanical Engineers, has remarked that, at 
 the high speeds (400 to 500 revolutions per minute) attained 
 by the screws of Thorneycroft's torpedo boats, the engines 
 seemed to run more smoothly than at lower speeds. This 
 has been noted by every builder, and every driver of fast 
 
STEAM ENGINES FOR 
 
 engines. The author, in handling naval screw engines of 
 short stroke and high speed, has frequently observed this 
 fact, and, after a somewhat wide range of experience with 
 engines of long and of short stroke, of from 15 to 500 revo- 
 lutions, and of powers ranging from the toy engine built 
 during his hours of leisure when a boy in a short jacket, to 
 marine engines rated at above 5,000 horse-power, at sea 
 and on shore, in the mill and the workshop or on the loco- 
 motive, he has never yet seen evidence pointing to any as 
 yet nearly reached limit to engine speed, except that which 
 is imposed by such conditions as we are gradually and 
 steadily modifying, as our knowledge and skill become 
 more nearly able to cope with the difficulties which arise in 
 our constantly changing practice. 
 
 It will have been observed that, in all the engines which 
 have been here described as adapted to direct connection 
 to the dynamo and to the (i first motion" shaft, some form 
 of balanced valve has been used. It has been seen that one 
 of the conditions of good regulation by a governor, which 
 determines the "point of cut-off," is that the work thrown 
 upon the governor shall be the least possible. This con- 
 dition evidently points to the use of some expedient, in 
 cases in which a positive-motion gear is used, by which the 
 resistance to motion of the valve, while a change is being 
 effected by the governor, shall be made a minimum ; this 
 evidently indicates the advisability of adopting some form 
 of balancing device. 
 
 The engine to be here described has been designed with 
 this end in view, as well as with the idea of securing a form 
 of machine which should be simple and inexpensive to 
 
ELECTRIC LIGHTING PLANTS. 
 
 121 
 
 build, and to keep in repair ; prompt and exact in regula- 
 tion under sudden variations of load, and as nearly isoch- 
 ronous in its governor-motion, as is practicable. It is of 
 the same general class with the last several described forms 
 
 Governor and Eccentrics. — Minimum Throw. 
 
 of engines, but differs from them in its details and in its pro- 
 portions, somewhat, and, especially, in the form of its valve, 
 and in the devices intermediate between governor and 
 valve. In this engine, the "piston " valve is used, com- 
 bined with a double port, such as was first used by Allen in 
 the locomotive slide valve. These details are illustrated 
 further on. The engine, as a whole, will be first described. 
 
122 STEAM ENGINES FOR 
 
 The accompanying engraving present two perspective 
 views of the Armington & Sims Engine, of the styles com- 
 monly used in driving electric light machinery. The bed 
 is seen to be of the kind already described in the account 
 of the Porter- Allen engine, heavy, solid, stiff, yet neat, and 
 even graceful, taking the bending stresses of the guides at 
 its upper surface, and insured against twisting strains by the 
 box form of its section. Two main pillow blocks, in the 
 first engine illustrated, carry its steel crank-shaft, and sup- 
 port the two wheels, one of which is a balance wheel, and 
 
 Crank- pin and " Wiper." 
 
 the other of which is the pulley, from which the engine is 
 belted to its work. The steam cylinder is overhung, and 
 the exhaust pipe is carried down below the floor, clear of 
 the foundation, which latter has a minimum extent, and 
 cost, while amply heavy, and is long and strong enough to 
 carry the engine steadily. In some cases, the frame is made 
 with but one pillow block, and the crank is overhung ; the 
 plan here illustrated is, however, a better one when the en- 
 gine is to be driven up to the now usual speeds of such 
 machines. 
 
 The journals are all large, and carefully calculated for 
 the speeds and pressures adopted. The designers make use 
 

 
 
ELECTRIC LIGHTING PLANTS. 1 2 5 
 
 of a method of calculation introduced some years ago, by 
 the author, which is based on the working of marine and 
 stationary engines, under his own management, or under 
 his own observation. The drain-pipes for the cylinder are 
 fitted as usual, but should be rather larger and more care- 
 fully planned, than is necessary where the engine has a 
 valve, which may lift from its seat should the boiler at any 
 time 'prime" or "foam," and send water over into the 
 cylinder with the steam. The provision for lubrication is 
 a matter of vital importance in all engines of this class. In 
 this engine the "sight feed " is used, in which each drop of 
 oil falls through a clear space, on its way to the point to be 
 oiled, in full view of the man in charge, and any failure of 
 the oil to "feed " is thus promptly detected. The crank- 
 pin is supplied by a " wiper " (see Fig.), which takes its 
 supply of the lubricant from the oil- cup at every revolution 
 of the crank. This device has been used, in very similar 
 form, by the author, on fast marine engines, with perfect 
 satisfaction, and it is found to work well here. 
 
 The two large engravings show opposite sides of the en- 
 gine, and the second exhibits the arrangement of a single 
 wheel, and of the steam-chest and valve mechanism. As is 
 here seen, a governor, of the same type as that exhibited in 
 the articles describing the " Buckeye " and the " Straight 
 Line " engines, is secured to the arms of the pulley on the 
 nearer side of the frame, and is arranged to adjust the 
 position of the eccentrics, which give motion to the valve 
 through a rod and valve stem, the connection between 
 which two parts is made at a point at which they can be 
 conveniently supported by a rockshaft and arm carried at 
 
126 
 
 STEAM ENGINES FOR 
 
 the middle of the length of the frame. The cranks are, as 
 seen in both illustrations, two discs in which the balancing 
 mass can be secured at any desired point. The width of 
 the pulley carrying the main belt is sufficient to take a belt 
 of such breadth, that the stress shall be about 35 pounds 
 per inch of its width. The main bearings are made with 
 boxes set at an inclination to the horizontal, and provision 
 
 Section of Cylinder, 
 
 is made for taking up wear. The crank-pin is of steel, 
 ground carefully to size, as is the universal practice among 
 good builders of this class of engines. In this machine the 
 main journals are also ground. The distance between main 
 
ELECTRIC LIGHTING PLANTS. 1 2 J 
 
 bearings is made as small as possible, to permit high speed 
 with little risk of springing the shaft. The front cylinder 
 head can be removed, when necessary, as shown in the next 
 illustration, independent of bed and cylinder alike. 
 
 As here shown in section, it is seen that the cylinder, 
 steam-chest and valve-seat are all in one casting, which is, 
 however, not a remarkably intricate one. It is best shown 
 by the perspective view, while the section next given will 
 afford a better idea of the arrangement of the valve. 
 
 The steam-chest, S, S, is in direct communication with 
 the boiler, and the valve, which is of the piston form with 
 a double steam-port (the second port being seen at P, P ), 
 is surrounded by the "live steam," thus taking steam at the 
 middle and exhausting it at the ends of the chest, at E, E. 
 The valve moves precisely as does the ordinary locomotive 
 slide valve, and, as here shown, is just taking steam at the 
 piston end of the cylinder, both directly past the shoulder 
 of the valve and through the secondary port at the oppo- 
 site end of the valve. Thus the steam is introduced, at the 
 beginning of the stroke, through a double length of port, 
 and hence, with unusual promptness when the engine is 
 running at high speed. The consequence is that it gives 
 approximately boiler pressure in the cylinder, and through- 
 out the stroke up to the point of cut-off, if the steam pipe 
 is short and direct, the steam line on the indicator diagram 
 is very nearly perfectly horizontal and straight from end to 
 end. This is a very unusual feature in diagrams from en- 
 gines having positive-motion valve-gear. The form of this 
 valve is well shown in the accompanying engraving, which 
 exhibits the valve apart from its casing. 
 
1 2 8 STEAM ENGINES FOR 
 
 All engines of this class will have been seen to be re- 
 markable for the shortness of their stroke of piston, as 
 compared with the diameter of cylinder. The section of 
 the cylinder just given, shows how advantageous is this 
 proportion in enabling the port-space to be reduced to a 
 comparatively small volume. In the engine of long stroke, 
 the port-space becomes seriously large and the compression 
 required to fill it introduces a considerable loss both of 
 power and efficiency, if the valve-gear used is of the type 
 here seen. In fact, it would be probably quite impractic- 
 able to secure such a steam distribution as would satisfy 
 the majority of engineers, were the engine of long stroke 
 and a single valve adopted moved by a link, or by such an 
 equivalent for the link as is here used. The total " dead 
 space" in these engines, including piston-clearance, is 
 sometimes as low as 5 per cent, on large sizes. In all cases 
 compression fills this space at every stroke. The piston- 
 valve has been often used by earlier builders, but that here 
 shown possesses a novelty in the double port. Its advan- 
 tages are the ease and cheapness with which it can be made 
 and fitted, and with which it can be replaced when worn, its 
 perfect balance and ease of working under any practicable 
 steam pressure, its permanence, tightness and remarkable 
 durability when properly cared for and used with boilers 
 supplied with good water. Its disadvantages are, the ra- 
 pidity with which it sometimes wears, when it is not kept 
 well lubricated, or when it is exposed to the action of steam 
 carrying over from the boiler acidulated or dirty water, the 
 danger of injury to the cylinder or its heads when priming 
 occurs, and the proneness of the attendant to neglect its 
 
ELECTRIC LIGHTING PLANTS. 
 
 129 
 
 repair when it requires such care These disadvantages 
 have sometimes proved to be so serious, as to give many 
 engineers a very strong prejudice against the valve ; on the 
 other hand, this unfavorable prejudice seems to be now 
 giving place to a decidedly favorable opinion, assuming that 
 the valve is well made and is to go into good hands, and to 
 be used under proper conditions, and these and some other 
 very successful makers have definitely adopted the piston 
 valve as a feature of their standard designs ; it is even 
 coming into use in marine engines of the largest size. In 
 
 Armington & Sims Valve. 
 
 the engine here under consideration, the valve is said by the 
 constructors to have proved eminently successful and to 
 have proven more durable than their earlier constructions, 
 in which they adopted a balance flat valve. It is probably 
 too early, as yet, to fully decide what are the exact relative 
 merits of the two kinds of valve. In this particular case, 
 the removal and replacement of the piston valve can be 
 done quickly and inexpensively, and a spare valve being 
 kept on hand, it is probable that its use may prove econom- 
 ical and satisfactory even where the water used for the 
 boiler is not of the best. 
 
 One of the most important, novel, and beautifully ingen- 
 
13° 
 
 STEAM ENGINES FOR 
 
 ious details of this engine, is its peculiar arrangement of 
 governor and eccentrics. These parts are exhibited in two 
 engravings. 
 
 The regulator is precisely the same, in principle, as those 
 already described as adapted to the adjustment of the 
 eccentric on the main or the governor shaft. It has the two 
 weights, i, i, carried on, and forming a part of arms piv- 
 
 Armington & Sims Governor and Eccentrics. — Maximum Throw 
 
 oted to the governor pulley, and revolving in the vertical 
 plane as usual in that class of governors. The position of 
 these weights, as determined by the speed and the action 
 
ELECTRIC LIGHTING PLANTS. 1 3 1 
 
 of the springs, determines the position of the eccentrics, C, 
 D, and thus the position and motion of the valve, and the 
 point of cut-off, flying out and giving a higher ratio of 
 expansion as the load on the engine is diminished, or as 
 steam pressure rises in the slightest degree, and a lower 
 ratio as these conditions are reversed. In the device here 
 adopted, however, the valve is driven by an eccentric 
 which is " duplex." One eccentric, C, is set inside another, 
 D, and connected to the governor arms in such a way 
 that, as the weights separate with increasing speed of en- 
 gine, both eccentrics are turned on the shaft so as to cause 
 their "throws" to coincide, or to separate, as may be 
 necessary. When they coincide, the travel of the valve is 
 due to a greater total throw, B, and is a maximum ; when 
 they are separated as far as possible, the throw becomes A, 
 and the travel is reduced to a minimum. The action is 
 almost precisely the same as that of a " Stephenson-link," 
 worked between full and mid-gear. When the two eccen- 
 trics give maximum travel, the action is that of the link- 
 motion in full gear ; when they are at opposite sides of the 
 shaft, the action is that of a link in mid-gear. By setting 
 them at intermediate points, the throw is made that is requir- 
 ed to give an intermediate action of the valve, and thus the 
 distribution of steam is made to accord with the demands 
 of the work by such a variation of the ratios of expansion 
 and of compression as is obtained by the link-motion, and, 
 in this case, with the advantage in promptness of opening 
 and of closure obtainable with a double-ported valve. The 
 range of action given in this engine is sufficient to permit a 
 
1 3 2 STEAM ENGINES EOR 
 
 range of cut-off from o to about three-quarters stroke. The 
 lead remains unchanged, and the compression increases as 
 the ratio of expansion is increased. 
 
 The springs of the governor are used in compression. 
 The distribution of steam at the usual speed, and with full 
 load, is shown by the accompanying illustration, which is a 
 copy of an indicator diagram taken from one of the engines 
 driving the large dynamos at the Edison station in New 
 York city. These engines are coupled directly to armatures, 
 
 Diagram Taken at the Edison Station. 
 
 and make with them 350 revolutions per minute. One of 
 these engines was recently kept at work 17 days, making 
 over 8,400,000 revolutions without stopping, and then was 
 not stopped because of any difficulty with the engine. 
 When examined by the author, they were doing their work 
 steadily and smoothly, and were not appreciably affected 
 by the sudden changes of load produced by throwing on 
 and off any considerable proportion of the lights on the 
 circuit. 
 
ELECTRIC LIGHTING PLANTS. 1 33 
 
 This engine illustrates well the perfection of regulation 
 attainable by these positive motion valve-gears attached to 
 this form of governor, to which attention has already been 
 called. At a trial of engines of this make made by the 
 author, to satisfy himself in regard to their action under 
 varying load, 25, 50, and sometimes 60 Thomson-Houston 
 arc lights were thrown on or off, and the variation of speed 
 was but one and two revolutions, respectively, in 280. No 
 special preparation or adjustment was allowed in this case, 
 and there is no reason to doubt that still closer regulation 
 and more perfect isochronism are attainable, if they, at any 
 future time, should prove to be desirable. These engines, 
 9^2 by 12 inch cylinders, had never been before tested, and 
 had done no work until started under the direction of the 
 author. The lamps demanded very exactly 0.7 horse-power 
 each, a fact which indicates that, as connection is there 
 made, there can be but little lost power between the engine 
 and the lamp. The form of card under load is seen below. 
 
 Diagram Taken by Thurston. 
 
1 34 STEAM ENGINES FOR 
 
 The success here obtained in the use of a single valve is 
 as encouraging as it is remarkable. While it can hardly be 
 expected that the economy of this system, other things be- 
 ing equal, can be fully up to that obtainable with the more 
 elaborate forms of valve-gear previously illustrated, there is 
 no question that it is so great that these simple forms of 
 engines will be able to find a market in that very wide field 
 in which their extreme simplicity of mechanism and their 
 moderate cost, as well as their successful operation at high 
 speeds, are qualities which compensate any such differ- 
 ences in cost of the steam supply. If the same distribution 
 of steam, and the same economy is obtained with the one 
 form of valve motion as with the other, and if, as is the 
 case to a very satisfactory degree with these engines, a cor- 
 rect form of indicator diagram can be obtained, it is to be 
 expected that the engine will be economical in its use of 
 steam. The increasing compression here noted with in- 
 creasing expansion is a decidedly advantageous feature, as 
 it has an important influence in checking losses by " cylin- 
 der condensation'* at high ratios of expansion, while also 
 reducing the waste due to large clearance spaces, where 
 such exist. 
 
 Every engine and every machine of importance, or re- 
 markable in any respect, as in such a combination, of in- 
 genious devices, effective combination, and efficient opera- 
 tion as is here illustrated, is, invariably, the outcome of a 
 long period of progressive invention, unintermitted experi- 
 ment and more or less steady growth from an initial stage 
 to its condition of successful adaptation to the demands 
 which it is especially fitted to meet. The Armington & 
 
ELECTRIC LIGHTING PLANTS. 1 3 5 
 
 Sims engine is no exception to the rule, and its inventors 
 and makers, as has been seen, are fortunate in having been 
 able to reap so satisfactory a harvest after so Jong a period 
 of growth and ripening. The engine is now built, not only in 
 the United States, but in Canada, Great Britain, France 
 and Austria. This American engine is in use on many 
 foreign steamers, and in numbers of European buildings, 
 public and private. It drives the dynamos in the British 
 Houses of Parliament. 
 
1 3 6 STEAM ENGINES FOR 
 
 V. 
 Fast Engines of Peculiar Design. 
 
 THE BALL ENGINE. 
 
 THE forms of steam engine which have been described 
 in the preceding articles have been chosen as being 
 fairly representative of what may be termed standard types 
 of engine as built by makers of reputation. It will be seen 
 that they present to the student of the steam engine several 
 distinct forms of machine, each of which is now acknow- 
 ledged to be well adapted to produce a certain result in the 
 application of heat energy, through the medium of steam, 
 to the production of power, and that each is especially fit- 
 ted to do its work under certain definite conditions, which 
 conditions are less completely met by the others. Each is 
 well-known in the market as an engine which has taken its 
 place among those which have passed the experimental 
 stage and may be relied upon to do good work if well built 
 and put in operation under the conditions that it is designed 
 to meet. They embody ideas and inventions which have 
 grown into form during years of experiment and faithful 
 trial and the variety of makes to be found in the market 
 belonging to each class, and differing only in the design and 
 construction of details, proves that the main principles 
 upon which each class is based are well established and 
 sound. 
 
 The engines now to be examined are distinguished by 
 certain peculiarities of design and construction which mark, 
 
ELECTRIC LIGHTING PLANTS. 
 
 m 
 
 in some cases, new departures, in other cases, peculiar ways of 
 reaching the end at which more familiar devices were aimed. 
 It has been seen that the regulation of the steam engine 
 has been found to be one of the most important matters to 
 which the attention of the engineer has been called. For 
 many purposes, the uniformity of motion of the engine is 
 an even more important quality than its economy in the use 
 
 The Ball Engine. 
 
 of fuel, or in all running expenses. A slight change of 
 speed in an engine driving dynamo-electric machine will 
 seriously injure the value of the light, in nearly every loca- 
 tion, and may sometimes entirely destroy it ; a moderate 
 variation of speed in the motor of a cotton mill making fine 
 goods may break more threads in the spinning department 
 
1 3 8 STEAM ENGINES FOR 
 
 or do more injury in the weaving room, than would be 
 compensated by the difference in economy between the 
 most efficient " automatic" engine ever made and the most 
 wasteful engine in the market. The principle of regulation 
 of the steam engine has been, from the time of the applica- 
 tion of the old " fly-ball" governor to the Watt engines of 
 a century ago to the present day, that of making the speed 
 of the engine determine the amount of steam that shall be 
 supplied to it. In the first engines used in the driving of 
 machinery, in the old " Albion Mills" erected by Watt and 
 his partners in London, in 1786, and for 50 years afterwards, 
 the governor adjusted the supply of steam by moving a 
 throttle valve. The governor was next arranged to deter- 
 mine the point of cut-off by Zachariah Allen, of Providence, 
 R. I., in 1834, and by George H. Corliss, in 1849, to adjust 
 the trip of his detachable valve-gear. From this latter date, 
 it has been the universal custom to so apply it in all engines 
 in which uniformity of motion and economy in the expen- 
 diture of steam were the controlling considerations in their 
 design. The method of accomplishment of this result has 
 been seen in the preceding pages, as practiced by Corliss 
 and Greene, and by the constructors of positive-motion 
 gears which have been the later outgrowth of modern 
 changes in the application of steam power. 
 
 Now, after half a century since the grand step taken by 
 Zachariah Allen has passed, and a generation after that 
 taken by Corliss, a new principle has been introduced into 
 the construction of the steam engine, viz., the control of 
 the speed of the machine, so far as it is due to the varying 
 load, by that variation of load > making the cause of the irre- 
 
ELECTRIC LIGHTING PLANTS. 
 
 139 
 
 gularity of motion its own corrective, and placing the regu- 
 lating principle between the work and the engine in such a 
 way that the latter may be made to preserve any given speed 
 with perfect uniformity, so far as it depends on the load, or 
 causing the speed either to be increased or diminished to 
 any desired extent by any given variation of load. 
 
 This idea, like all valuable inventions, has not been the 
 result of a single thought or the product of a single brain ; 
 it has been floating in the minds of thoughtful engineers for 
 a long time. It was proposed to the author, by one of the 
 generation of inventors just passed away, years ago ; but, 
 in its present form, it became practicable only after the in- 
 troduction of the high-speed engine had permitted the use 
 of the form of centrifugal governor seen in the engines last 
 described. The engine about to be considered embodies 
 the first practically useful application of this principle, in a 
 practically successful form of engine. 
 
 The Ball Automatic Expansion Engine is the invention, 
 so far as it differs essentially from other engines of its class, 
 of Mr. F. H. Ball, of Erie, Pennsylvania. In its general 
 form and in the details of construction, generally, it resem- 
 bles the last two engines which have been described. It 
 has a single-valve, positive motion valve-gear, and the solid 
 compact structure characteristic of all the so-called high- 
 speed engines. The accompanying illustration will give a 
 correct idea of its form and proportions. 
 
 The engine bed is of strong and stiff construction, and 
 very similar to others with which the reader has become 
 familiar. The steam-cylinder is overhung and bolted to a 
 faced flange as in the Porter-Allen engine. The main pil- 
 
1 40 S TEAM ENGINES FOR 
 
 low blocks are set in the bed of which they form a part, and 
 their caps are placed at an angle with the horizontal plane, 
 as is sometimes done in marine engines, and less frequently 
 in stationary engines. The system of boring the seat for 
 the cylinder, aligning the guides for the cross-head, and 
 boring out shaft-bearings, here adopted, gives perfect align- 
 ment ; and the preservation of the alignment is insured by 
 this unification of parts formerly detached. As is the case 
 with all good engines, the fitting parts are made to standard 
 gauge, and a system of inspection insures good work. Pack- 
 ing is dispensed with, and joints are made tight, by securing 
 exactly plane, and perfectly smooth, surfaces, at abutting 
 points. The wearing surfaces of the valves, and other 
 rubbing parts, are scraped to shape and exactness of form, 
 by the aid of surface plates. The valve is made tight un- 
 der steam-pressure, the form of the valve being such as to 
 permit this rather unusual operation. 
 
 The Ball Engine has a short stroke and high speed of 
 rotation, ranging as now built, from 7 to 10 inches diameter 
 of cylinder, 10 to 12 inches stroke of piston, and making 
 2 S° to 350 revolutions per minute. These proportions are 
 adopted, probably, principally with a view to meeting the 
 demands of electric lighting. 
 
 The essential and most peculiar feature of the Ball en- 
 gine, and that which gives it a place in this little treatise, 
 is, as has been already stated, its governor. 
 
 The Ball Governor is, in the main, like the governors 
 which have been described as controlling the several engines 
 which have been immediately herein before described. It 
 consists of a " governor-pulley," from the arms of which 
 

 ELECTRIC LIGHTING PLANTS. 
 
 141 
 
 are swung a set of weights, which are arranged to move in 
 the plane transverse to the shaft on which the pulley is car- 
 ried. These weights, or balls, are restrained from moving 
 outwards, under the influence of centrifugal force, by a set of 
 strong steel helical springs, secured, at one end, to the balls, 
 and at the other, to the rim of the pulley. Any movement 
 of the weights, in either direction, causes a motion of the 
 
 The Ball Governor. 
 
 eccentric, resulting in the alteration of the throw of the 
 valve in such a direction, and to such an extent as to bring 
 the engine very exactly to speed. To this extent, the Ball 
 governor is identical, in its general construction and in its 
 principles and mode of action, with those already familiar 
 to the reader. To this extent, it is possessed of the same 
 
1 4 2 STEAM ENGINES FOR 
 
 qualities as the others of its class, and it has been seen that 
 good workmanship and correct proportions and adjustment 
 may give wonderful nicety of regulation. 
 
 To this governor, as commonly built, Mr. Ball adds a re- 
 markably ingenious, and singularly simple yet perfect, in- 
 vention ; it is exhibited in the accompanying figures. The 
 first of these illustrations shows the governor-pulley detach- 
 ed from its shaft, and does not show the eccentric ; 
 it presents only the essentially novel part of the 
 device. 
 
 It is seen that, attached to the radius-bar of each ball, is 
 a small spring, connecting a point near the fulcrum of that 
 lever with the extremity of a strong, peculiarly shaped arm, 
 projecting from the hub on the shaft which is seen within 
 the hub of the pulley. The governor-pulley is set loosely 
 on this inner hub, which latter is keyed fast to the shaft. 
 The arrangement is evidently such that, the shaft being 
 turned by the engine, the effort must be transmitted 
 through the small spring to the weight arms, thence to the 
 pulley, and from the latter to the load to be driven, through 
 a belt carried on that pulley. The effect of this curious 
 disposition of parts is easily seen : Suppose the governor 
 to be so adjusted that, at normal speed and under the rated 
 load, the supply of steam and the distribution of that steam, 
 are precisely correct, as intended by the designer of the en- 
 gine. Now, if a variation of steam-pressure should occur, 
 the governor at once meets the consequent change of speed 
 by a corresponding change of steam-distribution, and the 
 variation of speed is restricted to a range, which, if the 
 governor is well proportioned and well adjusted, may be 
 
ELECTRIC LIGHTING PLANTS. 143 
 
 quite imperceptible to the senses, and hardly measurable 
 by count. 
 
 This governor here acts like all the others. But, sup- 
 pose the steam pressure to be unchanged, and the load to 
 vary — we now have a new movement introduced. The 
 force exerted in driving the load is transmitted through the 
 small springs which are peculiar to this governor, and 
 which connect the main shaft to the driving pulley, through 
 the governor. The instant that any relaxation, or any in- 
 creased tension, is felt here, the relaxation or the extension 
 of the springs, so produced, causes a change in the position 
 of the weight-arms, and a corresponding alteration in the 
 position of the eccentric ; and the steam supply is at once 
 readjusted to meet the variation of load. This may be 
 done so promptly and so exactly, that, however much the 
 load may vary, the speed of the engine remains precisely the 
 same. Load may be thrown on and thrown off to any extent 
 that may be found desirable or necessary, and the engine 
 goes on with its fluctuating task without an instant of visi- 
 ble change. Should both steam-pressure and load vary at 
 the same time, the load. strings set the example of changing 
 the steam distribution to meet the new conditions, and the 
 governor-springs controlling the balls are immediately seen 
 to yield to the effect of the varying steam-pressure, and to 
 continue their motion until the flying weights have set the 
 eccentric in correct adjustment to give the right speed. If 
 the governor is perfectly isochronous, the new adjustment 
 meets the case exactly, and the engine runs at the intended 
 speed as before. The load-springs may even be so adjust- 
 ed that an increase of load may produce a decrease of 
 
1 44 STEAM ENGINES EOR 
 
 speed to any desired extent, or, even more commonly and 
 usefully, so that a?i added load may give increased speed. 
 This latter is done in some cases when driving electric 
 lights, and also in saw-mills, and for other kinds of variable 
 work. In the former case, the engine is adjusted to give 
 standard speed when driving full load, and to reduce its 
 speed as lights are turned off ; in the latter, the engine 
 runs at speed while the saw is cutting, and slows down 
 when the work is off. 
 
 The next figure shows the eccentric. A is the main ec- 
 centric having an elongated shaft opening ; to this eccen- 
 tric is attached the arm B, of which the outer end is pivot- 
 ed, allowing the eccentric to swing across the shaft ; this 
 motion controls the time during which steam is admitted, 
 each stroke. This swinging motion is controlled by the 
 rotation of the disc, C, in the following manner : The disc 
 has a flange, Z>, on its side, which is eccentric to the shaft, 
 and on the inside of this eccentric flange is a ring, E, which 
 engages with a stud, F, in the main eccentric. Thus the 
 rotation of this disc forward and backward causes the ec- 
 centric to swing across the shaft. The disc has a sleeve 
 encircling the shaft and projecting through the elongated 
 shaft opening in the main eccentric, and on the end of the 
 sleeve is a flange nut, G, which holds the parts in place. 
 The rotation of the disc is produced and controlled by the 
 governing forces ; the centrifugal force of the weights met 
 by suitable springs ; and the resistance of the load equilib- 
 riated by the centrifugal force of the weights. 
 
 This form of governor is a very safe one, as, should 
 breakage of load-springs occur, the engine slows down or 
 
ELECTRIC LIGHTING PLANTS. 
 
 H5 
 
 stops. The risk of injury of this kind is unimportant, how- 
 ever, if the springs are properly made, as the load carried by 
 them is insignificant. A 50 horse-power engine, at 300 revolu- 
 tions per minute, carries a load of but about 500 pounds on 
 each load-spring. If correctly proportionated and made> 
 they should endure indefinitely. The endurance of all 
 these springs is the greater for the periods of rest frequent- 
 ly given them, and for the fact that they are, much of the 
 time, under very uniform tension. 
 
 The Ball Eccentric and Connections. 
 
 The practical result of this novel modification of old 
 methods of regulating the engine is that the regulation of 
 the steam-engine now can be made to cover more than the 
 
146 
 
 STEAM ENGINES FOR 
 
 simple preservation of a fixed velocity of rotation. It is 
 now possible to determine, within certain limits, not only 
 what degree of variation from normal speed shall be per- 
 mitted, but also what shall be the normal, and if desired, 
 varying, speed of the machine, with varying load. It may 
 not only be made to run at a certain fixed speed, but may 
 be caused either* to increase or diminish the speed, accord- 
 ing to a fixed, and economically desirable, law. This new 
 principle will probably find many applications, although 
 such problems have rarely come to the consideration of the 
 designing engineer, hitherto. 
 
 The accompanying peculiar diagrams are taken from the 
 recording apparatus of the " Moscrop Indicator," an in- 
 strument which automatically and continuously records the 
 speed of the engine and its variations. Each revolution 
 produces a dot, the height of which above the base-line in- 
 dicates the speed. The first of the two diagrams is from an 
 
 fi 
 
 Moscrop Speed Diagram. — Fair Regulation. 
 
 engine of 250 horse-power, fitted with an " automatic cut-off," 
 and furnishing power to a paper mill. It is claimed to do 
 good work ; but the author has no personal knowledge of it 
 
ELECTRIC LIGHTING PLANTS. 
 
 147 
 
 The second is furnished, by the owners of the Ball En- 
 gine, as illustrating fairly an equally trying case. The 
 author has other cards of this kind which, with great varia- 
 tion of steam-pressure, nevertheless are very smooth, al- 
 though not as smooth as that here reproduced. They are 
 also interesting as showing how useful a recording speed- 
 indicator may be. Such records are more satisfactory, in 
 comparing speeds of engines, than are even the best of 
 counters, and vastly more satisfactory than counting by the 
 watch, as they exhibit the rate of each revolution, together 
 with the variation of rate for extended periods of time. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 CO 
 
 
 3 
 
 *■* 
 
 <M 
 
 M 
 
 -H 
 
 iC 
 
 o 
 
 r«- 
 
 03 
 
 Ca 
 
 o 
 
 zi 
 
 ->» 
 
 co 
 
 -h 
 
 o 
 
 o 
 
 - 
 
 zn 
 
 * 
 
 S 
 
 7M 
 
 V! 
 
 bi 
 
 m 
 
 o 
 oj 
 
 -^ 
 
 ?5 
 
 
 urn 
 
 so 
 urn 
 
 co 
 
 Ml 
 
 7* 
 
 CO 
 
 till 
 
 ,ini 
 
 CO 
 Mil 
 
 O 
 
 co 
 inn 
 
 o 
 
 CO 
 
 ml 
 
 CO 
 Mill 
 
 CO 
 
 ■111 
 
 J 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 CO 
 
 
 
 
 
 
 
 
 
 
 
 r^ 
 
 
 
 
 
 
 
 
 
 
 
 
 <o 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Moscrop Speed Diagram. — Ball Engine. 
 
 This engine, with its novel governor, is one of the most 
 interesting products of mechanical ingenuity that has been 
 seen since the days of Watt. It will probably have but 
 little influence on the vitally important matter of steam- 
 engine efficiency, as that term is customarily applied, that 
 is to say, upon the economy of the engine in consumption 
 of steam and of fuel ; but it will undoubtedly, in many of 
 its applications, be found to have a very important effect in 
 adapting the engine to its work, and upon its efficiency in 
 that relation. 
 
148 steam engines for 
 
 THE IDE ENGINE. 
 
 r I ^HE engines which have been described are by no 
 -*- means the only engines which are deserving 01 
 mention, and of careful study, as illustrating the peculiari- 
 ties of the best modern practice in the field which it has 
 been the object of the author to explore. A number of 
 other engines, of one or another of the classes which have 
 been described and illustrated in the preceding articles, 
 have nearly or quite equal claims for consideration. Of 
 these engines, only typical or representative examples have 
 been sought, and have been selected from the machines 
 with which the author is most familiar. One more engine may 
 be here described— not as possessing the singular novelties of 
 design which distinguish some of those already examined* 
 but as affording a good illustration of the principles and 
 practice which have come to be recognized as distinctive of 
 the latest phase of that progress, which has recently been 
 so rapid, in the direction of improved methods of con- 
 struction, as well as of design, and in the application of the 
 modern materials of construction. The engine is one with 
 which the author cannot claim that personal familiarity 
 which has led, in some cases, to the selection of those which 
 have been previously considered; but a description, such 
 as is to be here given, will show that it may fairly be taken 
 as a representative of the best practice, in matters of detail, 
 which it is the special object of the writer now to exhibit. 
 
 The Ide Engine is of the same class with all the engines 
 described in the preceding section — a high-speed engine, 
 intended to be driven up to high power and to occupy 
 small compass; to regulate with all the accuracy desired in 
 

 ELECTRIC LIGHTING PLANTS. 
 
 U9 
 
 electric lighting, and in the spinning of fine cotton; to have 
 good wearing qualities, and to be economical in its use of 
 steam and of fuel. The illustrations exhibit its general 
 form, and the more important details of the machine. 
 
 Examining it in some detail, it will be observed that the 
 frame, although of novel design, is of the same general form 
 with those which have been already described in this class, 
 
150 
 
 STEAM ENGINES EOR 
 
 possessing that solidity and rigidity that have been seen to 
 be an essential feature of all successful high-speed engines. 
 The main pillow-blocks are formed in the frame; and the 
 cylinder is secured at the opposite end, overhanging as in 
 
 cases already familiar to the reader. The crank-pin is set 
 in a disc, which permits counterbalancing, and gives great 
 strength. The connecting-rod is tapered from the crank- 
 
ELECTRIC LIGHTING PLANTS. \ 5 1 
 
 in to the crosshead-end, in the manner now common to 
 all fast-running engines. The outlines of all visible parts 
 indicate strength and stiffness, and are very neat in design. 
 
 The valve-gear and governing mechanism are shown best 
 by the view of the opposite side of the engine, given in the 
 next engraving. The piston-valve is adopted, and is placed 
 directly under the steam-cylinder. This arrangement per- 
 mits most complete drainage of the cylinder, and thus less- 
 ens the danger of accident, should the entrance of water 
 with the steam occur to any serious extent. The placing 
 of the valve at the side is not an unusual feature of this 
 class of engine; but the arrangement here adopted is, in 
 this respect, still more advantageous. This arrangement 
 also affords a means of getting an equalization of the travel 
 of the valve relatively to that of the piston, which is an ad- 
 vantage. Still another advantage is that this position of 
 the valve-chest gives dry steam from the steam-chest, by 
 causing it to act as a trap, as well as drains the cylinder of 
 water that may have condensed within it. The connection 
 with the steam pipe is made above the line of connection 
 between the steam-chest and the cylinder, and it is thus 
 rendered possible to remove the former, and get at the 
 valve without disturbing the steam pipe. 
 
 The regulation is effected by a governor of the class 
 adopted in all engines of this kind, and the regulation and 
 the action of the valve are similar in character and in pre- 
 cision to those seen in engines already described. The range 
 of power, and the distribution of steam at various points of 
 cut-off, are shown very beautifully in the indicator diagram 
 here given, which was obtained by suddenly throwing off 
 
1-2 
 
 STEAM ENGINES FOR 
 
 the load; each revolution gives a distinct "card." Steam 
 may follow from the beginning nearly to the end of stroke, 
 with good exhaust and an excellent range of compression. 
 The speed of engine was here 225. The card was taken by 
 loading the engine to its maximum power by a Prony 
 brake, and then taking the diagrams while the governor 
 was adjusting the steam supply, the brake being at the mo- 
 ment released. The smallest card is therefore a " friction 
 card." The smoothness of action of the regulating mech- 
 anism is shown by the uniformity with which the power falls 
 off and the cards diminish in area. 
 
 Series of Indicator Diagrams. — Ide Engine. 
 
 The next diagram shows the range of work which such 
 engines are capable of doing, and illustrates very finely the 
 change in the distribution of steam which takes place in 
 this accommodation of the power of the engine to its load. 
 It is seen that the compression, as well as the expansion, 
 gradually changes in amount as the power varies, both act- 
 ing to reduce the area of the diagram with diminishing 
 

 ELECTRIC LIGHTING PLANTS. 1 53 
 
 power, or to increase it as the required power becomes 
 greater. A very interesting effect of this change is to give 
 increased economy in the use of steam by checking cylinder 
 condensation, the greatest known source of waste of heat, 
 just when that loss becomes most serious in both absolute 
 
 Indicator Diagram. — Ide Engine. 
 
 and relative amount. In some cases, the economy obtain- 
 ed, with considerable expansion, by the introduction of 
 large compression, has amounted to above 10 per cent. 
 Where superheating is adopted, this gain is less; but in the 
 usual case, using saturated steam, the use of the valve- 
 motion, of which an example is here illustrated, brings with 
 it a very important advantage; and nearly all builders of 
 such engines are now agreed in testifying to its value. The 
 lines of indicator diagrams obtained by the author from this 
 engine are unexcelled by any that he has yet seen from 
 engines of this class. 
 
 One very important feature of recent progress in the con- 
 struction of the steam-engine is well illustrated in the Ide 
 
1 54 STEAM ENGINES FOR 
 
 Engine, and affords a special reason for studying it; this 
 is the extensive use of steel in its running parts. Within 
 a few years it has become possible to obtain from the mak- 
 ers of Bessemer and " Open Hearth, ,, as well as of crucible, 
 steel, a quality of metal which earlier could not have been 
 obtained at all. This is a steel which is distinguished, 
 chemically, by its low percentage of carbon and its rela- 
 tively high proportion of manganese, and physically, by its 
 wonderful combination of ductility and strength. As the 
 proportion of carbon decreases in steel it loses strength; 
 but it gains ductility and malleability in a far higher ratio, 
 and thus it happens that the softer qualities are much bet- 
 ter fitted for use in machinery than are the very best of 
 wrought irons produced by the ordinary process of pud- 
 dling. The former are strong, tough, amply hard for all 
 such uses, and perfectly homogeneous; the latter are less 
 tenacious, often not as ductile, and are never homogeneous; 
 but are full of "cinder streaks," and have a fibrous struct- 
 ure that is objectionable, and is never seen in steels. 
 These steels are all made by casting molten metal into in- 
 got moulds, and thus securing comparative freedom from 
 cinder and defective structure. 
 
 The soft steels are displacing iron in every direction; 
 and the probabilities seem to be that in the course of time, 
 in the coming "Age of Steel," iron, puddled as is now us- 
 ual, will be entirely displaced by these, properly so-called, 
 "Ingot Irons." The Ide Engine, as well as other engines 
 now com'ng into market from the shops of the best build- 
 ers, illustrate this change of material. It has its piston-rod, 
 its connecting-rod, its valve-stems and links, and its smaller 
 
ELECTRIC LIGHTING PLANTS. T 55 
 
 journals, all of steel. Large castings are not usually made 
 in steel in this country, but all small parts are coming to be 
 made in that remarkable metal. 
 
 ENGINES OF THE NEW YORK SAFETY STEAM-POWER CO. 
 
 In the course of the somewhat extended series of descrip- 
 tions of standard forms of engine which is now soon to be 
 closed, it will have been observed that the tendency has 
 been toward the reduction in number of parts, and increas- 
 ing simplicity of mechanism as the speed of engine is in- 
 creased. The earlier types of engine having detachable 
 cut-off apparatus as a part of the valve-motion were engines 
 of moderate speed of piston and of comparatively long 
 stroke, and, therefore, of even more moderate speed of ro- 
 tation. The latter forms of standard engine are of simpler 
 construction, and of higher speed of piston, and of much 
 higher speed of rotation. This difference is not only due 
 to the necessity of reducing the number of parts and secur- 
 ing greater positiveness of action in the valve-gear, but it is 
 also due to the more general recognition of the fact that 
 economy of steam and fuel consumption is but one of the 
 economies to be studied in the use of steam as a motive 
 power, and that the cost of securing great economy of steam 
 and fuel may be such as to more than compensate the sav- 
 ing effected by such expenditure. This is especially true of 
 small powers, and common experience has shown that it is 
 seldom advisable to construct complicated valve-gears for 
 such engines, as the cost rarely comes within the commer- 
 cially economical limit. This principle has probably been 
 carried too far; and the author has no doubt that engines of 
 
1 56 STEAM ENGINES FOR 
 
 the higher grade may be often found commercially econom- 
 ical for even very small powers. The field for the simpler 
 class of small engine, nevertheless, is enormously extensive; 
 and the number annually built is very great. 
 
 But little attention, comparatively, has been paid to the 
 design and construction of small steam-engines until very 
 recently. The engineer has been too often inclined to look 
 upon this as too small a matter to demand the thought and 
 the time that he has freely given to larger and more at- 
 tractive work. It is now different, and some excellent 
 forms of small engines are to be found in the market. It 
 is the intention of the author here to describe a single ex- 
 ample of this class of machine, not as the only good engine 
 of the class, but as a type of this class. 
 
 The British builders of portable and agricultural engines 
 were the first to develop the art of steam-engine design and 
 construction in this department. A dozen years ago, they 
 were building engines of as little as 20, or even 10, horse- 
 power, which demanded but 3 pounds, and even less, of 
 coal per horse-power per hour. As early as 1867, they 
 reached the figure 4.13 pounds;* in 1870, it became 3.73, 
 and, in 1872, the Reading Iron Works built an engine of 20 
 horse-power which, on trial at Cardiff, required but 2]/^ 
 pounds of picked coal per hour and per horse-power. This 
 engine had a cut-off valve on the back of the main valve. f 
 Single valve engines have never done as well; but some of 
 them have nearly approached these figures. A consump- 
 tion of 5 pounds of coal per hour and per horse-power is a 
 
 * Mechanical Engineering at Vienna; Reports on the Vienna Exhibition: R. 
 H. Thurston, Washington, 1878. 
 t Ibid., page 100. 
 
ELECTRIC LIGHTING PLANTS. 157 
 
 good figure, and is rarely attained in such small engines. 
 The best of them may be expected to use from 5 to 7 
 pounds and to consume, therefore, from 40 to 60 pounds of 
 steam, averaging perhaps about 50, on the basis of the in- 
 dicated power. 
 
 Among the earliest of American engineers to turn atten- 
 tion to this department of mechanical engineering, were 
 Messrs. Babcock & Wilcox, who have become well known 
 as the inventors of a successful form of "sectional" steam 
 boiler. The style of engine which was designed and intro- 
 duced by them, and built by the New York Safety Steam 
 Power Co., has now become as generally accepted as stand- 
 ard among builders of small engines as has the Corliss en- 
 gine among constructors of drop cut-off engines. It has 
 been copied in all parts of Europe, as well as in the United 
 States. This may be taken as representative of the best 
 methods of construction in this country, and as exhibiting 
 the elegance in proportions, and that excellence of material 
 and workmanship, which are now becoming recognized as 
 desirable in steam-engines of even the smallest size. In 
 fact, as has been seen, the opportunity here offered for im- 
 provement, and for economizing steam and fuel consump- 
 tion, is much greater than with large engines; and these 
 excellencies are, therefore, the more desirable. 
 
 The engraving exhibits the form of the engine here to be 
 described. It is a "vertical engine" mounted upon a base- 
 plate of neat and strong form, and with the steam-cylinder 
 bolted by the lower head to a very strong and very graceful 
 frame. The main journals are carried in bearing construct- 
 ed in the frame, and consequently free from liability to loss 
 
r 5 8 
 
 STEAM ENGINES FOR 
 
 of perfect alignment, or to unequal wear. The valve is 
 either a plain, locomotive-slide, or, preferably, a piston valve. 
 The latter is fitted in a detachable seat, which can be 
 easily removed for renewal of seat and valve, should acci- 
 dent or wear ever make it necessary. 
 
 N. Y. Safety Steam Power Co.'s Engine. — 5 h. p. 
 
 The vertical position of the engine prevents wear within 
 the cylinder becoming serious or unsymmetrical. The 
 pistons are hollow, and are packed with rings set with suf- 
 

 ELECTRIC LIGHTING PLANTS, 
 
 T 59 
 
 ficient spring to keep them up to a bearing. The cross- 
 head, which is shown in the following engraving, has its 
 gibs turned to fit the guides in the frame, which latter are 
 part of the casting of the frame and are bored out in line 
 with the cylinder, and cannot possibly get out of line. 
 
 Crosshead. 
 Hi 
 Crosshead. 
 
 The engine above illustrated is of small size — 4 or 5 
 horse-power — and has been especially designed for electric 
 lighting purposes. The governor is that known as the 
 "Waters Governor ;" it regulates by adjusting the supply of 
 steam passing to the engine through a throttle valve — a 
 method which seems to have been here more successful 
 than is usual in engines having to perform so exacting a 
 kind of work. The speed of this engine is usually about 
 250 revolutions per minute. 
 
 Larger engines of this style are often constructed ranging 
 up to 100 horse-power. The heavy engines, when of 15 to 
 100 horse-power, are given an independent crank-shaft 
 pillow-block and a counterbalanced disc-crank. In these 
 engines, of all sizes, the modern innovation of the use of 
 steel for running parts is very generally introduced. The 
 rods, pins, and minor parts are of this metal; the bearings 
 
1 60 STEAM ENGINES FOR 
 
 are usually of bronze lined with Babbitt metal, and are 
 given large area. Crank-shafts are either of steel or of 
 
 10 H. P. Vertical Engine. — N. Y. S. S. P. Co. 
 hammered iron. As is customary with all well con- 
 structed engines, these engines are set up and operated in 
 the shop long enough to exhibit all defects and to afford 
 
ELECTRIC LIGHTING PLANTS, 
 
 161 
 
 opportunity to make all adjustments before sending them 
 out, and are thus made safe against those annoying delays 
 which otherwise attend the introduction of such machines. 
 The parts are made to gauge, and therefore interchangeable; 
 and it is thus made easy to replace them when worn or in- 
 jured, at minimum expense and with little delay. The 
 
 900000 O OOOOO O OO000C ( 
 
 B^b 
 
 I0000 0OOO O OOOOOOt 
 
 Semi-Portable Engine. 
 
 valves, and their seats, even, when worn, are taken out, sent 
 to the shop, and the spare valve and seat, already fitted, 
 takes the place of the parts removed. 
 
1 62 STEAM ENGINES FOR 
 
 Where engines are of large size, they usually have the 
 engine room and boiler room distinct; with these small 
 engines, however, it is found often to be desirable to place 
 engine and boiler side by side, and even upon a common 
 base, as is illustrated by the last of the preceding engravings. 
 This forms what is known, frequently, as the "semi- 
 portable " engine, to distinguish it from the "portable," 
 which last named style is mounted on wheels. 
 
 THE ERICSSON AND WESTINGHOUSE ENGINES. 
 
 A LL of the engines which have been considered in the 
 •^^ preceding articles are of one general type — that 
 known as the " double-acting reciprocating engine. ,, Before 
 the time of James Watt, the only engine in extended use, 
 even in the limited field in which the steam engine was then 
 employed — that of pumping water from mines — was a "sin- 
 gle-acting" engine — the Newcomen engine, which had then 
 almost entirely superseded the so-called engine of Savery. 
 Watt invented, first, the separate condenser, and then the 
 double-acting engine, thus increasing the power of the ma- 
 chine and rendering it, at last, applicable to the turning of 
 a crank and the driving of machinery and mill-work. In 
 the " single-acting engine," the steam drives the piston in 
 but one direction, and the return stroke must be made 
 without the production of useful work. In the " double- 
 acting engine," the steam acts upon the piston in both di- 
 rections, and with practically equal effect. Thus, a more 
 regular action is secured with a given weight of balance 
 
ELECTRI^ LIGHTING PLANTS. J6? 
 
 wheel, or the same regularity with a wheel of one-half the 
 weight of that required for the older form of engine. This 
 smoothness of motion is, in such work as is here considered, 
 one of the most essential features of the best steam engine 
 economy. At the speeds which have been now attained, 
 however, the inertia of moving parts becomes so great that 
 moderate variations in the impelling power become com- 
 paratively insignificant, and have no perceivable effect upon 
 the smoothness of revolution of the crank-shaft. 
 
 The double-acting engine evidently possessed greater 
 power than its predecessor, when of the same size, and the 
 "efficiency of the machine ,, was correspondingly increased. 
 
 The very conditions which have been thus made to aid 
 in securing regularity have, however, introduced a new dif- 
 ficulty: At every revolution of the engine, the crank 
 "turns the centre" twice; and, at every passage of the 
 centre, the direction of pressure upon the crank-pin is re- 
 versed, thus producing a shock which is proportional to the 
 difference of pressure, the suddenness with which it is felt 
 at the pin, and the extent of the "lost motion" between 
 the pin and its bearings. Some lost motion must always be 
 permitted here, to avoid danger of heating of the journal 
 and injury to the machine. The counteracting adjustments 
 are found to be, usually, the utilization of the inertia of the 
 reciprocating parts, as in the Porter- Allen engine; the 
 adoption of heavy compression, as in the several engines 
 afterward described, and very careful adjustment of the fit 
 of the brasses on the pin. With the skilful use of these 
 expedients, and with the introduction of a perfection of 
 workmanship, and of such qualities of material, as have 
 
;64 STEAM ENGINES FOR 
 
 never before been seen, the " high-speed engine " has been 
 made successful at as high as 400, and even, in some cases. 
 600 revolutions per minute. The lower of these figures may 
 be taken as that representing the maximum in standard, and 
 usually best, practice. 
 
 But much higher speeds than these are sometimes de- 
 manded; and engines must, in the future, be built to run, 
 regularly, steadily, and safely, at, probably, very much 
 higher velocities. This may, ultimately, lead to radical 
 changes in the design of the now standard forms of fast en- 
 gines. Nevertheless, the limit of speed has by no means 
 been reached, even at the higher of the above speeds, with 
 the common type of engine. The speed of even 450 times 
 the cube root of the length of stroke, now a common figure, 
 and three times that given by James Watt's rule, is occa- 
 sionally greatly exceeded. Captain Ericsson designed an 
 engine, some three years ago, for the electric lighting ap- 
 paratus of the Delamater Iron Works, which has now been 
 running, every evening for two or three years, at 1,250 
 revolutions per minute, without giving the slightest trouble, 
 or meeting with the most insignificant accident. The pis- 
 ton speed is about twice that of the average " high-speed M 
 engine, and six times that adopted by Watt. It is probablj 
 the highest speed ever attained by a reciprocating engine 
 doing work for which it had been designed. 
 
 The object of the inventor was to design a steam engine 
 for the special work of driving small dynamo electric ma- 
 chines, and hence to secure great stability and strength, a 
 minimum number of parts requiring lubrication, and abso- 
 
ELECTRIC LIGHTING PLANTS. 
 
 165 
 
 lute certainty that the parts retained should be, at all times, 
 thoroughly supplied with the lubricant. The engine is 
 therefore made a " half trunk " engine, the trunk, F, F, 
 serving as an oil reservoir. The joint in the eccentric rod 
 is provided with a piston moving in a cylindrical guide, 
 JV 9 which is also an oil reservoir. The cylinder, (7, and 
 base-plate, F, are in one casting, upon which is set the 
 
 The Ericsson Engine. 
 hollow frame supporting the crank-shaft, H y F y and balance 
 wheel. Every journal and rubbing part has an oil reser- 
 voir and special provision for effective lubrication. The 
 whole engine is a model of the product of that most efficient 
 kind of ingenuity which seeks definite ends by the most 
 
T 66 STEAM ENGINES FOR 
 
 simple and directs means. Its performance leaves nothing 
 to be desired. 
 
 The limits to velocity of piston and speed of rotation 
 have, from the beginning of steam engine practice, been 
 thus gradually set farther and farther back; and one 
 after another of the limiting conditions have been suc- 
 cessfully met and overcome. The earliest limit was that 
 found in the bad workmanship and material which Watt 
 and his contemporaries encountered, and which gave rise 
 to heated journals at even what would now be considered 
 very low speeds, and at very small powers. This defect 
 being gradually overcome, the next, and a comparatively 
 modern, difficulty was found in wear, and the " pound," 
 which took place when the lost motion of journals in the 
 line of the connecting rod was taken up, at the passing 
 of the centres. This difficulty was met in two ways, as 
 already repeatedly stated — by making use of the inertia 
 of the reciprocating parts, as was done by Porter and 
 Allen, and by heavy compression as is practiced in nearly, 
 or quite, all of the high speed engines of to-day. The 
 first method can be adopted only when careful propor- 
 tioning, after calculation, of the weights and velocities of 
 the moving parts, has determined the proper weights of the 
 compensating pieces. The latter adjustment may be made 
 either by calculation or by experimentally finding the com- 
 pression giving smoothest running. This effect of increas- 
 ing compression can be most satisfactorily seen in the ma- 
 rine engine, in which, whatever the speed of the machine, 
 and whatever the steam pressure, or however loose the 
 journal, the link may be raised so as to gradually check the 
 
ELECTRIC LIGHTING PLANTS. 
 
 167 
 
 pounding at the centres, and finally to eliminate it altogether, 
 the engine often being thus brought to work silently and 
 smoothly at speeds far above those which, without compres- 
 sion, would be very troublesome, if not absolutely danger- 
 ous. This is an experiment which the writer has repeated 
 on many engines, and almost invariably with the same satis- 
 factory result. 
 
 Some lost motion must always be permitted at the crank- 
 pin, and these expedients are usually found to meet the case. 
 They probably have their limits, however. There comes a 
 time, as speeds are increased, when the weight of running 
 parts, as calculated for strength only, becomes as great as is 
 desirable to effect the compensation by their inertia ; there 
 comes a time, as compression is increased, when the "cush- 
 ioned" steam is carried up to boiler pressure, and this would 
 seem the natural limit in this matter. The next device, 
 chronologically, adopted by the engineer, is that of prevent- 
 ing the lift of the brass of the crank-pin and of the cross- 
 head pin at the turning of the centres, while still leaving the 
 freedom of fit required to give safety from heating. This 
 last expedient is that which has led to the construction of a 
 class of engines which are as peculiar and as typical as either 
 of the classes which have been already described. 
 
 THE WESTINGHOUSE ENGINE 
 
 belongs to this new class, and is here taken as its represen- 
 tative. The change of construction characteristic of this 
 type of engine is a return to the original " single-acting" 
 plan of engine. This has been often proposed, and not in- 
 frequently attempted ; but the success attained has not, as 
 a rule, been satisfactory. Two, and three, and four, cylin- 
 
i68 
 
 STEAM ENGINES FOR 
 
 ders have been tried, in the endeavor to secure regular mo- 
 tion while taking steam only on one side of the piston ; very 
 
 The Westinghouse Engine. 
 
 high speeds of revolution have been attained ; but the cost 
 of steam has been found too great, and their use has not 
 become general. The Westinghouse engine has proved it- 
 
ELECTRIC LIGHTING PLANTS. 169 
 
 self to possess the elements of commercial success, and is, 
 therefore, to be taken as illustrating what can be done in 
 this direction, by good designing and good business man- 
 agement. 
 
 It is evident that, if steam pressure comes upon but one 
 side of the piston, the engine can pass its centre without 
 the brass lifting clear of the pin, and thus may be driven 
 up to any speed without liability of injurious pounding. 
 For enormously high speeds, as the engineer of to-day 
 looks upon them, this is evidently the type of engine to be 
 looked to for smooth and successful working. The illustra- 
 tions show how, in the Westinghouse engine, this end is 
 reached. The engine has two cylinders, A, A y fitted with 
 single-acting pistons, Z>, D, forming trunks filling the bore 
 of the cylinder, giving a long steam-tight bearing, and taking 
 the connecting-rod pin, A, B, at a point at which no tenden- 
 cy to rock the piston can be produced. The top of the 
 piston is cored out to prevent transfer of heat from the 
 working to the non-working end. The rods, F, F, take 
 hold of the crank-pins within an enclosed chamber, C, form- 
 ing part of the engine frame, F, C. This frame and bed- 
 plate also acts as a reservoir for oil lubricating the journals 
 and pistons, which oil floats on water and is dashed up over 
 the moving parts so enclosed, at every revolution of the 
 engine. No other attention is required than to keep a sup- 
 ply of oil in the chamber, by filling as loss occurs by leak- 
 age. In fact, the whole engine is thus shut in by its frame, 
 and its working parts are invisible, while working — an 
 arrangement at once a means of security and convenience. 
 
 The valve adopted in the Westinghouse engine is a piston 
 valve of the class already described, but having some pecu- 
 
170 STEAM ENGINES FOR 
 
 liarities specially adapting it to its use in this engine. Its 
 guide, y, is a piston traversing a cylinder separating the 
 exhaust space from the chamber below. This one valve, J 7 ", 
 distributes steam to both cylinders, the two cranks being set 
 directly opposite each other. This adjustment of the cranks 
 also gives a perfect balance of reciprocating parts, and se- 
 cures smoothness of movement of the whole machine, what- 
 ever speed may be adopted ; and exceptional speeds of 1,000 
 revolutions, or more, per minute are reached without obser- 
 vable vibration. 
 
 The governor, /, and its action, are precisely like the same 
 parts in the engines described in several of the earlier arti- 
 cles. It actuates the eccentric, and determines the point of 
 cut-off by varying the throw of the valve, while retaining 
 the lead. The governor is usually so adjusted that it will 
 not come into play until the engine falls i per cent, below, 
 or rises i per cent, above, the normal speed ; its full traverse ' 
 is effected, also, within this range, the intention being that 
 the speed shall never vary more than i per cent, from that 
 fixed as its proper velocity. The range of expansion is 
 from o to about 5-8 stroke. 
 
 One of the dangers to which fast running engines are 
 peculiarly exposed is that of injury by the entrapping of 
 water in the cylinder, and the plunging of the piston 
 against the mass of incompressible fluid which then fills the 
 clearance spaces. In this engine, in addition to the relief- 
 cocks, or valves, which are always fitted to such engines, a 
 safeguard is introduced in the form of what engineers are 
 accustomed to call the " breaking-piece, " a part which is 
 made purposely weaker than other portions of the machine, 
 exposed to a common danger, so that this piece may go 
 
ELECTRIC LIGHTING PLANTS. 
 
 173 
 
 when danger arises. This piece is always one the replace- 
 ment of which will give little trouble, and make but little 
 expense. In the Westinghouse engine, such a breaking- 
 piece is made to form a part of the cylinder head. This 
 
 The Westinghouse Engine. — Cross Section Through Valve. 
 
 may be knocked out without injury occurring to any impor- 
 tant, or costly, part of the structure.* 
 
 * The writer planned an engine, about the year 1860 in which the whole 
 cylinder-head was made a safety valve which could lift and discharge the water 
 into the chamber behind it, the cover of the latter being bolted on, while the 
 cylinder-head was only held in place, against a faced joint, by steam pressure. 
 
ELECTRIC LIGHTING PLANTS. 
 
 173 
 
 when danger arises. This piece is always one the replace- 
 ment of which will give little trouble, and make but little 
 expense. In the Wcstinghouse engine, such a breaking- 
 piece is made to form a part of the cylinder head. This 
 
 The Westinghouse Engine. — Cross Section Through Valve. 
 
 may be knocked out without injury occurring to any impor- 
 tant, or costly, part of the structure.* 
 
 * The writer planned an engine, about the year 1860 in which the whole 
 cylinder-head was made a safety valve which could lift and discharge the water 
 into the chamber behind it, the cover of the latter being bolted on, while the 
 cylinder-head was only held in place, against a faced joint, by steam pressure. 
 
i 7 4 STEAM ENGINES FOR 
 
 This breaking-piece is intended to yield at a safe pres- 
 sure — 200 lbs. per square inch — and thus save the engine. 
 The workmanship on these engines, so far as the writer has 
 been able to examine it, is excellent ; and the material of 
 the best. These are, however, as has been stated, absolutely 
 essential features of every good high-speed engine. The 
 engines are, when finished, set up in the shop and tested up 
 to their rated power, before sending them out ; and it is 
 thus made certain that they are in good order and in cor- 
 rect adjustment. The ingenious and novel methods of se- 
 curing certainty of lubrication, in this engine, the constant 
 direction of the actions tending to produce heavy strains, 
 the small number of parts subject to wear and to breakage, 
 the remarkable success met with in the attempt to reduce 
 the labor of attendance and cost of maintenance, and all 
 other costs causing reduction of commercial efficiency ; the 
 compactness, solidity, steadiness, safety at maximum speeds, 
 and general effectiveness of this engine, are such as to make 
 it one of the most interesting examples of the steam engine 
 of to-day that has yet attracted the attention of the engineer. 
 
 The economy of the later style of this engine — that 
 fitted with automatic expansion gear, as here described — 
 is probably about the same as that of other small engines 
 of its own class ; not, as a matter of course, equal to the 
 economy of large engines of the four-valve type, but great 
 as compared with the class of small engines to which the 
 manufacturer has usually been compelled to resort up to 
 the present time, when demanding but little power. The 
 loss by " friction of engine" is somewhat greater in 
 this form than in the more familiar type of engine. The 
 
ELECTRIC LIGHTING PLANTS. 175 
 
 peculiar advantages possessed by the engine in this di- 
 rection are its high piston and rotative speed, and the 
 extent to which compression is carried. One of these 
 engines has been driven experimentally up to 2,700 revo- 
 lutions per minute without any observable ill effect. 
 Their speeds are probably safely made double that of the 
 average "high-speed engine" with which we are now 
 becoming familiar. Compression, as an element in eco- 
 nomy of engine, has already been considered at some 
 length. It was shown by the writer, ten years ago, that 
 progress in the direction of improvement of the steam 
 engine has always been retarded by the difficulty of pre- 
 venting serious losses by cylinder condensation, and that 
 this is the essential element of preventible waste ; it was 
 also suggested by him, several years since, that probably 
 the best means of controlling the speed of engine is by the 
 introduction of high compression and its variation by 
 the governor, increasing compression with increasing ex- 
 pansion, and the reverse, and thus, by utilizing the heat of 
 compression, checking cylinder condensation as its increase 
 is caused by extending the expansion period ; and it was 
 pointed out that " the best among existing forms of valve 
 gear should, if judged by from the standpoint here taken, 
 be that which, combining a variable expansion with a variable 
 compression, is also capable of prompt and exact adjust- 
 ment by a sensitive and efficient governor."* This sug- 
 gestion, as has been seen, is fully met by all the later 
 designers of engines of the high-speed class. The engine 
 
 * Expansion of Steam, etc., Trans. Am. Soc. Mech. Engrs., 1881 ; Jour. Fran. 
 Inst., Oct. 1881. 
 
176 STEAM ENGINES FOR 
 
 above described illustrates well this use of compression; 
 the compression is adjustable by the governor, and may 
 thus given be that ratio which is best adapted to the case. 
 
 Mr. Harris Tabor, in a paper read before the American 
 Society of Mechanical Engineers, following the idea just 
 presented, says of compression: " It is to the proper con- 
 trol of compression that we must now look for further ad- 
 vance in steam economy. ,, It has been seen that this is one 
 of the directions of present advance. 
 
 Retrospect. — We have now made a tolerably complete 
 survey of the whole modern field of steam engineering as 
 far as it is covered by stationary engine practice, and have 
 seen a very steady progress from the best types of a gene- 
 ration ago to the most representative examples of the most 
 modern forms. It is seen that the direction of change is 
 still that which, as has been often pointed out by the writer, 
 has been observed from the days of James Watt. The 
 principal points found worthy of notice have been the in- 
 crease in economy and general efficiency by a tentative and 
 empirical, but none the less steady and uninterrupted, 
 method of advance. The pressures of steam have been 
 slowly, but constantly, rising; speeds of piston, and of rota- 
 tion, have been as constantly increasing; the effectiveness 
 of the governor has been made greater and greater; the 
 ratio of expansion at maximum efficiency has been very 
 slowly increased, by the gradual reduction of cylinder con- 
 densation; commercial considerations have been brought 
 definitely into view; the efficiency of engine has been im- 
 proved by reduction of size, weight, and friction of engine; 
 and thus we have been able to see a gradual change of type 
 
ELECTRIC LIGHTING PLANTS. 177 
 
 of engine effected, the engineer modifying his designs to 
 meet the demands of the time, until we have insensibly, 
 and almost without suspecting that progress has been going 
 on, passed across a new line and entered upon an epoch, in 
 steam engine construction, as marked in its period and as 
 well defined, as to its beginning, as was that which, at the 
 middle of the century, was distinguished by the introduc- 
 tion of the inventions of Sickles, Corliss, and Greene. 
 
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 ELECTRIC .-. ILLUMINATION 
 
 GENERAL PRINCIPLES, CURRENT GENERATORS, 
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 Chiefly compiled from "Engineering^" 
 
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 Life Saving and other Inventions. 
 
 THE EDSON RECORDING AND ALARM GAUGES 
 
 furnish written " Charts" in a permanent form, of the Speed of Machinery, 
 or, of the Pressure of Steam, Air, or Water within any boiler, pipe or 
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 The record is a continuous line or tracing made upon a ribbon of paper, 
 graduated by horizontal lines, into a scale of pressure, and by vertical lines 
 to a scale of time or of distance, or rate of speed or motion. 
 
 The " Chart" is moved by a Chronometer which is exactly regulated 
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 per hour (nearly). The portion of " Chart " traced upon should be critically 
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and his associates during the celebrated Steam Boiler trials at the American 
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 Stevens' Institute of Technology for its experimental work, and by its 
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 VIBRATING ALARM GONG AND 
 
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 To be placed in Engine Boom or 
 
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EDSOH'S SPEED AND PRESSURE RECORDING GAUGE. 
 
 This Instrument gives records simultaneously of the steam or water 
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 of time the speed was interrupted — as of a train of* cars — and between what 
 stations, and whether unlawful speed was afterwards resorted to, in recover- 
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 Perfection in electric lighting cannot be reached until uniformity shall 
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