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 RICHARDS' 
 
 A C O N 
 
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 REESE LIBRARY 
 
 OF TBB 
 
 UNIVERSITY OF CALIFORNIA., 
 
 Received J_ *r^5fc# &&/, 7<?f ^ 
 
 Accession? No. .^(f^l-vb Shelf No. ... 
 
A TREATISE 
 
 R I C H A K D S 
 
 STEAM-ENGINE INDICATOR 
 
 DIRECTIONS FOE ITS USE. 
 
 BY CHARLES T. PORTER. 
 
 REVISED, 
 
 WITH NOTES AND LARGE ADDITIONS AS DEVELOPED BY AMERICAN 
 
 PRACTICE ; WITH A SUPPLEMENT, DESCRIBING THE LATEST 
 
 IMPROVEMENTS IN THE INSTRUMENTS FOR TAKING, 
 
 MEASURING, AND COMPUTING DIAGRAMS. 
 
 ALSO, AN APPENDIX, 
 CONTAINING USEFUL FORMULAS AND RULES FOR ENGINEERS. 
 
 BY F. W. BACON, M.E., 
 
 OF THE AMERICAN SOCIETY OF CIVIL ENGINEERS. 
 
 OUKTH EDITION. 
 
 NEW YORK : 
 
 D. VAN NOSTRAND, 
 33 MURRAY STREET. 
 
 1883. 
 
Copyright, 1873, y Z>. F Nostrand. 
 
 Copyright, 1880, ^ Z>. Fa Nostrand, 
 

 PREFACE. 
 
 IN introducing the Richards Improved Steam- 
 Engine Indicator, we desire to call the attention of 
 the numerous class who, as constructors, managers 
 or owners, are interested in the steam-engine, to 
 the advantages which it possesses. In the follow- 
 ing pages all necessary information is furnished 
 concerning the instrument and its application, and 
 such instruction is given to those who are not al- 
 ready skilled in the use of the Indicator, as will en- 
 able them to employ it to the best advantage. 
 
 The Indicator was invented by Watt. For some 
 time it was kept by him a secret, but became known 
 before his death, and to its use, now quite general, 
 we are more indebted than to anything else, for 
 the degree of excellence which the steam-engine 
 has attained. The employment of more rapid 
 velocities of piston, with higher pressures of steam, 
 and higher grades of expansion, which has become 
 so extensive and promises ultimately to be uni-- 
 versal, has increased greatly the importance of the 
 Indicator ; since this is the only means as yet 
 known, by which the engineer can render himself 
 
4: PREFACE. 
 
 familiar with the action of steam under these new 
 conditions. Unfortunately, every form of this in- 
 strument has hitherto failed in its application to 
 engines of this class. The long and tremulous 
 spring used in them was put in a state of violent 
 oscillation by the momentum of the piston and 
 attached parts, and the result was a serrated 
 figure, from which but little information could be 
 extracted ; so that, after a time, attempts to 
 employ the Indicator in this important and 
 rapidly enlarging field were qiiite abandoned. 
 
 Under these circumstances, the appearance at 
 the Great Exhibition of 1862 of the improved form of 
 this instrument, invented by Mr. Charles B. Richards, 
 an engineer of Hartford, Connecticut, U. S., may 
 not improperly be regarded as an event of some 
 importance. The action of this Indicator was 
 found to be quite perfect, under the severest tests 
 to which it could there be subjected, and recently 
 it has been still more thoroughly tried, on an 
 express engine on the London and South-Western 
 Railway, and its performance has more than real- 
 ized the expectations formed of it. Two instru- 
 ments, among the first manufactured by us, were 
 employed, with which nearly two hundred dia- 
 grams were taken, on a trip to Southampton and 
 back, at pressures varying from 80 Ibs. to 130 Ibs., 
 at rates of motion varying from the slowest up to 
 260 revolutions per minute, giving a speed of 55 
 miles per hour, and at all points of cut-off ; and 
 
PREFACE. 5 
 
 they were found uniformly to work with the same 
 steadiness at the highest velocity as at the lowest, 
 and at the earliest point of cut-off as at the latest. 
 Copies of a few of the diagrams are here given. 
 
 We do not claim for these Indicators superiority 
 on engines running at high velocities only, though 
 certainly it is there most apparent where others 
 will not answer at all ; but we believe also, for 
 reasons herein explained, that they will be found 
 in practice to be the only correct Indicators for en- 
 gines running at any speed, even the lowest. 
 
 We have only to add, that no pains have been 
 spared to attain, in the manufacture of these instru- 
 ments, the highest degree of accuracy and excel- 
 lence, and that if the directions here given are 
 attended to, their indications may be implicitly re- 
 lied on. 
 
 ELLIOTT BROTHERS. 
 
PREFACE. 
 
 THE demand for an elementary treatise <on the 
 Richards Steam-Engine Indicator, together with 
 the solicitation of professional friends, has induced 
 me to undertake the preparation of the work. 
 
 The original and very excellent work of Mr. Por- 
 ter, now out of print, being principally an illustra- 
 tion of English engines and English practice, leaves 
 room for a work combining American engines and 
 American practice. 
 
 I have therefore used much of Mr. Porter's, and 
 added new matter and new diagrams the result 
 of a large experience, extending over six years. 
 
 The new diagrams introduced were, with one or 
 two exceptions, taken by myself. 
 
 The diagrams taken November 14th, 1867, from 
 the locomotive No. 50, built by the " Taunton Lo- 
 comotive Works, " are believed to be the first ever 
 taken in this country from a locomotive when mak- 
 ing a regular trip with an express train. 
 
 It will be of interest to the American engineer 
 to compare them with those from an English loco- 
 motive, as shown in the work. 
 
8 
 
 In order to make the work more useful to the 
 practical engineer, an Appendix has been added, 
 containing various formulas, which, during an ex- 
 perience of more than thirty years as a practical 
 engineer, have been collected, but never before 
 given to the public. The new rule to measure and 
 compute diagrams (page 42), will be found a very 
 expeditious and correct mode. The liabilities to 
 error being reduced as ten to one. It was brought 
 to my notice by Mr. Chas. E. Emery, engineer, New 
 York City. It is now for the first time published, 
 so far as I know. 
 
 The prime object has been to give nothing that 
 is not known by practical experience to be correct, 
 also to give it in a way that will be understood by 
 any one capable of filling the place of an engineer. 
 
 F. W. BACON. 
 
 BOSTON, October, 1873. 
 
PREFACE TO THIRD EDITION. 
 
 A THIRD edition of this work is called for, 
 -*-\* showing that the Indicator is now being- 
 appreciated. Engineers are becoming educated in 
 its use ; it reveals to them many things which they 
 thought they knew, but find they didn't ; it has got 
 the attention of engine constructors ; it has inspired 
 the genius of the inventor and designer ; the speed 
 of the engine is increased, the immense ponderous 
 mass of matter formerly set in motion is largely re- 
 duced, space is economized, compounding is shown 
 to be a success and a necessity, coal and water bills 
 are being reduced to a minimum. 
 
 All these desirable things, it is safe to say, the 
 teachings of the Indicator has not only rendered 
 possible, but has accomplished de facto. 
 
 Still there is a wide margin yet to fill before its 
 office is accomplished. 
 
 Increasing the speed of the engine rendered an 
 improvement necessary in the Indicator, which our 
 
x PREFACE: TO THIRD EDITION. 
 
 Supplement shows to have been admirably accom- 
 plished by Mr. Thompson. 
 
 The measurement and computation of diagrams 
 heretofore was a long, tedious, and unsatisfactory 
 work ; now the Planimeter has been produced, at a 
 price that can be reached by all, it has reduced the 
 time and labor to a few minutes, with the greatest 
 accuracy. 
 
 F. W. BACON, M. K, 
 
 No. 8 PEMBERTON SQUABE, BOSTON. 
 
RICHARDS 
 
 IMFKOVED 
 
 STEAM-ENGINE INDICATOR. 
 
 THE NATURE AND USE OF THE INDICATOR. 
 
 THE Steam-Engine Indicator is an instrument 
 designed to show the pressure of steam in the 
 cylinder, at each point of the piston's stroke. It 
 does this in the following manner : A pencil, 
 moving up and down with the varying pressure of 
 the steam, draws a line on paper, which has a 
 motion backward and forward, coincident with 
 that of the piston. The paper is placed on a 
 drum, which, while the piston is advancing, is 
 caused to make about three-quarters of a revolu- 
 tion, by means of a cord connected with a suitable 
 part of the engine, and while the piston is rece- 
 ding, is brought back to its first position by the 
 reaction of a spring. The pencil is attached to a 
 small piston, moving without friction in a cylinder, 
 1* 
 
10 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 and the motion of which is resisted by a spring of 
 known elastic force. 
 
 TLe pressure of the atmosphere is always on 
 the upper side of this piston, and when the com- 
 munication with the cylinder of the engine is 
 closed, it is on the under side also ; and if then 
 the motionless pencil be applied to the moving 
 paper, it will draw a line which is called the 
 atmospheric line. When the commiTjiicatioii is 
 opened between the under side of this piston and 
 one end of the cylinder of the engine, the piston 
 will be forced upward by the pressure of the 
 steam, or downward by that of the atmosphere, 
 as the one or the other preponderates ; and if 
 now the pencil be applied to the moving paper, it 
 will describe, during one revolution of the engine, 
 a figure, each point in the outline of which will 
 show, by its distance above or below the atmos- 
 pheric line, the pressure in that end of the cylin- 
 der, when the piston was at the corresponding 
 point of its forward or return stroke. The spring 
 which resists the motion of the Indicator piston 
 is so proportioned in strength that a change of 
 pressure of one pound on the square inch shall 
 cause the pencil to move up or down a certain 
 fractional part of an inch. 
 
 The diagram thus described shows on inspection 
 tho following particulars, viz., what proportion of 
 the boiler-pressure is obtained in the cylinder ; 
 how early in the stroke the highest pressure ia 
 
RICHARDS' STEAM-ENGINE INDICATOR. 11 
 
 reached ; how well it is maintained ; at what point, 
 and at what pressure, the steam is cut off ; whether 
 it is cut off sharply, or in what degree it is wire- 
 drawn ; at what point, and at what pressure it is 
 released ; in a non-condensing engine, whether it 
 is freely discharged, or what proportion of it re- 
 mains to exert a counter-pressure ; in a condens- 
 ing engine, the amount of the vacuum, and how 
 quickly, or how gradually it is obtained ; and in 
 both classes of engines, whether, before the com- 
 mencement of the stroke, there is any compression 
 of the vapor remaining in the cylinder, and if so, 
 at what point it commences, and to how high a 
 pressure it rises. From the diagram, the mean 
 pressure exerted during the stroke, to produce and 
 to resist the motion of the piston, may be ascer- 
 tained, and thus the engineer may come to l^now 
 accurately the amount of power required to over- 
 come the whole aggregate resistance on the engine, 
 and also, by taking separate diagrams for each, the 
 power required by each of the several resistances 
 or classes of resistance separately.* He may en- 
 
 * This we find of great use when called to determine (as 
 we often are) the power used by tenants. The landlord lets 
 power to his tenants ; it is fixed at a given price per horse- 
 power. The question arises, how much the tenant does use. 
 This is accurately determined. The practice is this: We take 
 several diagrams, one from each end of the cylinder, when 
 the engine is doing all the work, noting the number of revo- 
 lutions being made when each pair is taken. Should there 
 
12 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 deavor also to ascertain the causes of the various 
 features presented in the diagram, and thus to 
 learn the effect produced by this or that form or 
 arrangement of parts, and to detect any imperfec- 
 tion in their construction or action. 
 
 It must be borne in mind, that the Indicator 
 shows only the pressure at each point of the 
 stroke; to represent this faithfully is its sole office. 
 It tells nothing about the causes which have de- 
 termined the form of the figure which it describes. 
 The engineer concludes what these are, as the 
 result of a process of reasoning, and this is the 
 point where errors are liable to be committed. 
 
 be a difference of speed of the engine during the time of 
 taking these diagrams it is noted on each pair, and arranged 
 when worked up. 
 
 These diagrams and the result we mark "all on;" then we 
 stop tenant No. 1, throw off the belt that carries his work, 
 take say three pairs of diagrams, and work them up. Now, as 
 much as these are less than the average of those taken with 
 "all on," so much we charge tenant No. 1. We then put his 
 belt on and proceed with tenant No. 2, and charge him in the 
 same manner. Thus we proceed with all. In making up 
 our accounts for each, and adding them, we find the aggre- 
 gate will fall short of the gross of "all on." This is as it 
 should be, from the well-known fact that the friction of the 
 engine and intervening machinery decreases as the power 
 required decreases, and vice versa. 
 
 This amount of decrease or increase, as the case may be, 
 we have found to vary from 5 per cent, to 8 per cent, de- 
 pending on circumstances. Whatever it may be it should be 
 charged to the tenant. 
 
RICHARDS' STEAM-ENGINE INDICATOR. 13 
 
 Conclusions which seem obvious sometimes turn 
 out to have been wrong, and the ability to form an 
 accurate judgment, as to the causes of the pecu- 
 liarities presented in a diagram, is one of the 
 highest attainments of an engineer. 
 
 The variety of diagrams given by different en- 
 gines, and by the same engine tinder different 
 circumstances, is endless ; and there is perhaps 
 nothing more instructive to the student of engi- 
 neering, as there is nothing more interesting to 
 the accomplished engineer, than their careful and 
 comprehensive study, with a knowledge of the mod- 
 ifying circumstances under which each one was 
 taken. Lines at first meaningless become full of 
 meaning; that which scarcely arrested his atten- 
 tion, comes to possess an absorbing interest; he 
 becomes acquainted with the innumerable variety 
 of vicious forms, and learns the points and degrees, 
 as well as the causes, of their departure from the 
 single perfect form; he becomes familiar with the 
 effects produced by different constructions and 
 movements of parts, and competent to judge cor- 
 rectly as to the performance of engines, and to 
 advise concerning changes, by which it may be 
 improved; he ceases to be a mere imitator of ma- 
 terial shapes, and learns to strive after the highest 
 excellence, and, at the same time, to comprehend 
 its conditions. No one at the present day can 
 claim to be a mechanical engineer who has not 
 become familiar with the use of the Indicator, and 
 
14 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 skilful in turning to practical advantage the varied 
 information which it furnishes. 
 
 This brief summary of the uses of the Indicator 
 would be incomplete without calling attention to 
 the importance of applying it to boilers, as a means 
 of testing the accuracy of the pressure-gauges, and 
 to pumps, for the purpose of ascertaining the causes 
 of any inefficiency in their action, and also to the 
 condenser and the air pump of condensing engines. 
 
 The diagram, No. 1, taken from one of the 
 engines of a well-known steamship,* is introduced 
 here to illustrate the action of the Indicator, as 
 just described. 
 
 The scale of the Indicator was twelve pounds to 
 the inch. The line A B is the atmospheric line, and 
 c D the line of perfect vacuum. The lines forming 
 the outline of the diagram will be designated, for 
 convenience of description, as follows : 
 
 The line from a to 6, the admission-line. 
 
 6 to c, the steam-line. 
 
 " c to d, the line or curve of expansion, 
 
 " d to <?, the exhaust-line. 
 
 " e to /, the line of counter-pressure. 
 
 " / to a, the compression-line. 
 
 * The engines from which the diagrams here employed for 
 illustration were taken, will not be mentioned, except in two 
 or three exceptional cases ; the object of this paper being, not 
 to publish the comparative performance of different engines, 
 but to give instruction to those who may require it, in the use 
 of the Indicator. 
 
RICHARDS' STEAM-ENGINE INDICATOR. 15 
 
 The steam-line does not in fact end at c, but at 
 some unknown point beyond c. The diagram is divi- 
 ded by lines drawn perpendicular to the atmospheric 
 line into ten equal parts, and also by lines drawn 
 parallel with the atmospheric line at intervals of 
 five wounds pressure. The object of these is to 
 enable the engineer to observe more accurately the 
 nature of the diagram, and to ascertain the mean 
 pressure exerted during the stroke, the mode of 
 doing which will be explained hereafter. The line 
 <? g is the theoretical expansion curve drawn from 
 the point c. 
 
 . From an examination of this diagram, we con- 
 clude that the exhaust-port was covered at the point 
 /, of the return stroke, and the vapor remaining in 
 the cylinder was then compressed by the advance 
 of the piston to a density, at the commencement of 
 the forward stroke, of about five pounds above the 
 atmosphere. The port was then opened for admis- 
 sion, and the pressure instantly rose to fourteen 
 and a half pounds above the atmosphere. The 
 port being opened wider and wider, this pressure 
 was maintained behind the advancing piston to the 
 point c, at which it began to fall, at first very 
 slowly, from the gradual closing of the port by the 
 cut-off valve. The point at which the port was 
 covered cannot be identified. It was certainly, how- 
 ever, far beyond the point c, and strictly the steam - 
 line continues to the point of cut-off, however the 
 pressure may fall before that point is reached. At 
 
16 RICHARDS' STEAM-ENGINE, INDICATOR. 
 
 the point d, the pressure had fallen by expansion to 
 two pounds above the atmosphere. Here the valve 
 began to open communication with the condenser, 
 and before the piston commenced its return stroke 
 the pressure on this side of it fell to nearly ten 
 pounds below the atmosphere, and almost imme- 
 diately after a vacuum of twelve pounds was formed ; 
 and when the return stroke was two-thirds accom- 
 plished, the counter-pressure suddenly fell half a 
 pound lower, and this vacuum was maintained 
 until the exhaust-port was closed at the point /. 
 We shall refer to this diagram again, when on the 
 subjects of calculating the power of the engine from 
 the diagram, and of working steam expansively. 
 
 OF TEUTH IN THE DIAGBA.M. 
 
 It is, of course, of the first importance that the 
 diagram given by the Indicator shall be true. 
 Causes of error appear at every point, and the de- 
 gree of falsity arising from them increases greatly 
 with an increase in the rate of revolution of tho 
 engine. It is not possible to be too critical in using 
 the Indicator, especially at high speeds; the errors 
 we are not conscious of are the ones sure to mis- 
 lead us. 
 
 The Conditions of a correct Diagram are 1st, 
 that the movements of the paper shall coincide ex- 
 actly with those of the piston ; and, 2nd, that the 
 
RICHARDS' STEAM-ENGINE INDICATOR. 17 
 
 movements of the pencil shall simultaneously and 
 precisely represent the changes of pressure in that 
 end of the cylinder to which the Indicator is 
 attached. 
 
 1st. Errors in the Motion of the Paper. The com- 
 mon errors in communicating motion to the paper 
 are of two kinds those which arise out of the 
 movements employed, and those which, when the 
 movements are correct, are occasioned by a high 
 velocity of the parts; but with proper care these 
 may all be avoided. We shall mention them in 
 detail presently, in connection with instructions for 
 applying the Indicator. 
 
 2d. Errors in the Motion of the Pencil. These 
 are of a more serious nature. The spring may be 
 accurate, but its unavoidable length and weakness, 
 and its weight, joined to that of the piston 
 and other attached parts, and the distance through 
 which these must move, in order that the indica- 
 tions may be on a scale of sufficient magnitude, 
 render it impossible to obtain from engines which 
 run at any considerable speed, with any form of 
 Indicator hitherto in use, diagrams which can make 
 any claim to accuracy. 
 
 THE RICHARDS INDICATOR 
 
 Is constructed on a plan by which it is found that 
 these difficulties are quite avoided, and correct dia- 
 
18 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 grams are obtained under all circumstances. The 
 principal distinguishing features of this instrument 
 are a short and strong spring, a short motion of 
 piston and light reciprocating parts, combined with 
 a considerable area of cylinder, and an arrange- 
 ment of levers and a parallel motion, for multiply- 
 ing the motion of the piston in such a manner that 
 the diagram is described in the usual way and of 
 the ordinary size. The proportion between the 
 motion of the piston and that of the pencil is a 
 matter of discretion; that which has been adopted 
 is 1 to 4, and the steadiness with which the indica- 
 tion is drawn by these instruments, even at the 
 highest speeds of piston, leaves nothing to be de- 
 sired. 
 
 The diagrams numbered 2, 3, 4, 5, are fair sam- 
 ples of a large number taken from the locomotive 
 " Eagle," on the London and South- Western Rail- 
 way, in April, 1863. In three of them, the pencil 
 was held to the paper during a number of revolu- 
 tions ; in diagram No. 5 it passed over the paper 
 only once and a half. They are introduced here to 
 show the correct action of the instrument; we shall 
 have occasion to consider them also as illustrations 
 of working steam expansively. 
 
 General Construction of the Indicator. The paral- 
 lel motion is made as compact as possible. For 
 this purpose, a lever of the third order is employ- 
 ed to multiply the motion, and the extremities of 
 
KICHABDS" STEAM-ENGINE INDICATOR. 19 
 
 the line drawn by the pencil are permitted to have 
 a slight curvature, which considerably reduces the 
 length of the rods, and does not affect the use- 
 fulness of the instrument, the curvature at the 
 lower end being below any attainable vacuum, 
 while the extremity of the scale above is very 
 rarely employed. 
 
 The Indicators are made of a uniform size; the 
 area of the cylinder is one-half of a square inch, 
 its diameter being .7979 of an inch. The piston is 
 not fitted quite steam-tight, but is permitted to leak 
 a little; this renders its action more nearly friction- 
 less, and does not at all affect the pressure on 
 either side of it. The motion of the piston is f $ of 
 an inch, and the motion of the pencil, or extreme 
 height of the diagram, is 3| inches. The paper cyl- 
 inder is 2 inches in diameter, and the length of the 
 diagram may be 5 J inches, if this extent of motion 
 is given to the cord. The diagram is drawn by a 
 pointed brass wire on metallic paper. This is a 
 great improvement over the pencil ; the point lasts 
 a long time, cannot be broken off, and is readily 
 sharpened, and the diagram is indelible.* The 
 steam-passage has two or three times the area usu- 
 
 * We have used the metallic pencil with thf prepared me- 
 tallic paper. It works well, but the difficulty of procuring it, 
 together with its high cost, renders it objectionable. We use 
 heavy, unsized paper with a Faber No. 4 pencil ; we succeed 
 in getting good, distinct diagrams, with lines sufficiently fine 
 to measure correctly. 
 
30 EICHABDS' STEAM-ENGINE INDICATOR. 
 
 ally given to it. The stem of the Indicator is coni- 
 cal, and fits in a corresponding seat in the stop- 
 cock, where it is held by a peculiar coupling, shown 
 in section in the accompanying cut of the Indica- 
 tor. This arrangement permits the Indicator to 
 be turned round, so as to stand in any desired po- 
 sition, when, the coupling being turned forward, 
 the difference in the pitch of the screws draws the 
 cone firmly into its seat; and when the coupling is 
 turned backward, the cone is by the same means 
 started from its seat. The leading pulleys may be 
 turned by some pressure, to give any desired direc- 
 tion to the cord, and will remain where they are 
 set. By these means the Indicator can be readily 
 attached in almost any situation. 
 
 The Springs. In order to adapt this Indicator 
 for use on engines of every class, springs are made 
 for it to 4 different scales, as follows : 
 
 No. 16, which is graduated 16 Ibs. to the inch. 351bs. 
 
 No. 20, " " 20 " " " 56 " 
 
 No. 30, " " * 30 " " " 75 " 
 
 No. 40, " " 40 " " 105 " 
 
 All the above will also indicate 15 Ibs. below the 
 atmospheric line. 
 
RICHARDS' STEAM-ENGINE INDICATOR. 21 
 
 PEACTICAL DIRECTIONS FOB APPLYING AND 
 TAKING CARE OF THE INDICATOR 
 
 I. OF ATTACHING THE INDICATOR. 
 
 When it is practicable, diagrams should be taken 
 from each end of the cylinder. The assumption 
 commonly made, that if the valves are set equal,, 
 the diagram from one end will be like that from 
 the other, will be shown by this instrument to be 
 erroneous. This is owing to the difference in the 
 speed of the piston at the opposite ends of the 
 cylinder, which is, at the outer end of a direct- 
 acting engine, from one-sixth to one-third greater 
 than at the crank end, the difference varying ac- 
 cording to the degree of angular vibration of the 
 connecting rod. In side-lever, or beam-engines,, 
 these proportions are reversed, and the speed of 
 the piston is greater at the upper end of the cylin- 
 der. Often, also, there is a difference in the 
 lengths of the thoroughfares, and in the lead, or 
 the amount of opening, or the point of closing ; 
 and many times the valves are supposed to be cor- 
 rectly set when this Indicator will show that they 
 are not. These, and many other causes, will make 
 a difference in the diagrams obtained from the op- 
 posite sides of the piston. 
 
 Pipes to be avoided. The Indicator should be 
 fixed close to the cylinder, especially on engines 
 working at high speeds. If pipes must be used r 
 
22 RICHARDS' STEA.M-EXCUXE INDICATOR. 
 
 they should not be smaller than half an inch in 
 -diameter, and five-eighths in the bends, and as 
 ;short and direct as possible. Any engineer can 
 ;satisfy himself with this instrument that each inch 
 of pipe occasions a perceptible fall of pressure 
 between the engine and the Indicator, varying ac- 
 cording to its size and number of bends and the 
 speed of the piston. Diagrams have been known 
 to show, from this cause alone, forty per cent, less 
 pressure than was actually in the cylinder. 
 
 Where to connect the Indicator. On vertical cylin- 
 ders, for tne upper end, the Indicator-cock is 
 usually screwed into the cover, where the oil-cup 
 is set, this being removed for the purpose. For 
 the lowar end, it is necessary to drill into the side 
 of the cylinder, at a convenient point in he space 
 between the cylinder bottom and the piston, when 
 on the centre, and screw in a short bent pipe, with 
 A socket on the end to receive the Indicator-cock. 
 The Indicator can be used in a horizontal position ; 
 but it will be found much more convenient to put 
 in a bent pipe, and set it vertical. Sometimes it 
 will be necessary to drill in the side of the cylinder 
 at the upper end also, especially in double-cylinder 
 -engines having parallel motions, when the Indicator 
 cannot generally be set on the covers. Care must be 
 taken that the piston does not cover the hole when 
 on the centre. No putty is necessary to make 
 these small joints, and it should never be used, as 
 
RICHARDS STEAM-ENGINE INDICATOR. 2 
 
 it is liable to clog the instrument. If the screw fits- 
 loosely, a few threads of cotton wound round the 
 stem will prevent the escape of steam. Objections 
 are sometimes made to drilling a cylinder or its; 
 heads, for the reason that the borings as the drill- 
 passes through will be left in the cylinder and 
 likely to scratch it; this, with a little management,, 
 can be wholly prevented, by letting a little steam 
 on as the drill enters, which will blow it outwards. 
 
 On horizontal engines, the best place for the 
 Indicator is on the top or upper side, at each end;; 
 if it cannot be placed there, bent pipes may be 
 screwed into the covers or into the side of the 
 cylinder. In other respects follow the directions- 
 given for vertical engines. The Indicator should 
 never be set to communicate with the thorough- 
 fares. The current of steam past the end of the 
 pipe or the hole reduces the pressure in the instru- 
 ment, and the diagram given is utterly worthless, 
 as any engineer can readily ascertain by making 
 the experiment. On oscillating cylinders care must, 
 be taken to set the instrument in such a position 
 that the motion of the cylinder will not have the 
 effect to throw the pencil to and from the paper. 
 
 The stopcock being screwed firmly to its place, 
 screw the Indicator down to its seat, turning it to 
 the most convenient position, and make it fast by 
 turning the coupling; then move the guiding pul- 
 leys to their proper position to receive the cord,, 
 and the instrument is in readiness for use. 
 
34: RICHARDS STEAM-ENGINE INDICATOR. 
 
 II. OF GIVING MOTION TO THE PAPER. 
 
 Tiie Drum the best Means. The revolution of a 
 drum is probably the most correct as well as con- 
 venient method of giving motion to the paper. It 
 may be supposed that a flat slide, worked by posi- 
 tive means, would have a perfectly accurate motion; 
 but, in fact, at high velocities, where alone any 
 trouble is met with, the difficulties involved in its 
 use are more troublesome than those presented by 
 the cylinder. In most cases the connecting-rod 
 must necessarily be somewhat long; it must not 
 tremble, or the line on the paper will be tremulous, 
 :and the weight required for stiffness, joined to the 
 weight of the slide, causes a momentum, which, if 
 the rod is worked by a vibrating arm, will give fo 
 the paper, on each centre, a motion opposite to 
 that of the piston of the engine ; and precisely at 
 these points it is of the greatest consequence that 
 the two motions shall coincide. 
 
 In the use of the 'cylinder at any speed, the ques- 
 tion of obtaining a positive motion, if there is no 
 -elasticity in the cord or the parts to which it is 
 -connected, is simply one of proportion between the 
 momentum of the revolving parts and the strength 
 of the spring by which this is resisted. In this In- 
 dicator these parts are made as light as possible 
 -consistently with other requirements, and the 
 spring is of such strength that they may be reci- 
 procated from 250 to 300 times per minute, without 
 
RICHARDS' STEAM-ENGINE INDICATOR. 25 
 
 any increase in the length of the diagram, and of 
 course, therefore, without any error in the motion. 
 There is no difference in the construction of these 
 Indicators in this respect, it being intended that 
 every instrument shall be applicable to any engine. 
 
 From what Points to derive the Motion. This may 
 be taken from any part of the engine which has a 
 motion coincident with that of the piston. For a 
 beam-engine a point on the beam, or beam-centre, 
 or on the parallel-motion rods where these are em- 
 ployed, will give the proper motion; but care must 
 be taken that the cord be so led off, that when the 
 engine is on the half stroke it will be at right angles 
 to whatever gives it motion (a requirement too 
 often omitted) ; afterwards its direction of motion 
 may be changed as required, always taking care, 
 however, to use as few carrying pulleys as possible, 
 and the shortest possible cord, which should be of 
 linen, size No. 3 ; it should be well stretched by 
 suspending a weight to it for several days. 
 
 In some cases it is most convenient to take the 
 motion from a point on the end of the revolving 
 shaft ; this is frequently the case on horizontal en- 
 gines, working at high speeds, because then the 
 motion does not need to be reduced. Exact accu- 
 racy cannot be got in this way, however, without 
 -employing a moving slide, and connecting it with 
 the pin in the end of the shaft by a rod or cord of 
 such length that its angular vibration shall be the 
 2 
 
26 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 same as that of the connecting-rod. This will be 
 found generally a troublesome matter; and the en- 
 gineer will probably prefer in most .cases to disre- 
 gard the error resulting from its omission which 
 is, that the motion of the paper will be more near- 
 ly equal at the two ends of the stroke, being slower 
 than that of the piston at the one end, and faster 
 at the other. The crank or pin from which the 
 cord receives its motion must be on its centre re- 
 latively to the direction of the cord, whatever that 
 direction may be, precisely when the crank of the 
 engine is on Us centre. If this requirement is not 
 carefully attended to, the diagram will be worth- 
 less. 
 
 Q-enerally, on horizontal engines, the motion of 
 the paper is taken from the cross-head. In an 
 engine-room, a strip of board may be suspended 
 from the ceiling, or carried off horizontally in such 
 a manner as to permit it to swing backward and 
 forward edgeways by the side of the guides, and 
 motion may be given to it by a pin, secured firmly 
 to the cross-head, and projecting through a slot in 
 the board, in which it should fit nicely to prevent 
 lost time on the centres. To save drilling and 
 defacing the cross-head to insert a pin, we use a 
 clamp made fast to the cross-head or some of its 
 appendages by a set screw ; a projecting pin plays- 
 in a slot in the board, or if preferred, a short con- 
 necting rod may be used to make the connection. 
 The board must hang plumb when the piston is in 
 
RICHARDS' STEAM-ENGINE INDICATOR. 27 
 
 the middle of its stroke, or if horizontal at right 
 angles. The cord may be connected to this 
 strip of board at a point sufficiently near to its 
 point of suspension to give the required reduction 
 of motion for the paper, and must be led off in a 
 horizontal direction, and then over one or more 
 pulleys in any required direction to the Indicator. 
 At high speeds, however, pulleys should be avoided. 
 On portable engines, the motion may be attained in 
 the manner just described, the lever swinging from 
 a pin supported in a standard about two feet in 
 height, set on one of the guide-bars. 
 
 On locomotives having outside connections, the 
 motion must be taken from the cross-head. It is 
 indispensably necessary to use only a short direct 
 cord, free from elasticity, and connected to a point 
 the motion of which is reduced from that of the 
 cross-head by positive means. Care must be taken 
 also so to proportion the parts employed for this 
 purpose, that the point at which the cord is con- 
 nected shall have a positive motion without any 
 fling, a matter not by any means free from difficulty 
 at 250 revolutions per minute. A rock-shaft, 
 turning in bushings, supported by two angle iron 
 standards, precisely over the mid-position of that 
 point of the cross-head from which the motion is 
 derived, affords perhaps the best means of redu- 
 cing the motion. A long-arm is worked by the 
 cross-head and a short-arm gives motion to the 
 cord. The short-arm must be keyed in such a po 
 
28 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 sition that when the piston is in the middle of its 
 stroke it will stand at right angles with the direc- 
 tion of the cord, whatever that may be. The di- 
 rection of the cord may form any necessary angle 
 with the horizontal line, but must be at right 
 angles with the rock-shaft. 
 
 On locomotives having inside connections, and 
 a single pair of driving-wheels, where it is practi- 
 cable, it will be found to be the better way to take 
 the motion from a pin set in the end of the shaft, 
 and to communicate it by a connecting-rod to a 
 point convenient for attaching the cord. The parts 
 should be all substantially made; the momentum of 
 the connecting-rod will be perfectly resisted by the 
 pin. 
 
 On oscillating engines, the motion may be taken 
 from the brasses at the end of the piston-rod. If 
 the stroke is long, it is sometimes difficult to re- 
 duce this motion to that required for the paper, and 
 in such cases it is necessary to Jbake the motion 
 from an eccentric on the main shaft, to a point as 
 near as possible to the trunnion, and thence to 
 communicate it to the Indicator. In all these con- 
 nections, it is of the first consequence that there be 
 no lost time, which will require to be made up on 
 every centre, and will thus cause the paper to stand 
 still while the piston is moving. 
 
 Pulleys of different diameters on the same spin- 
 dle have often been used as a means of reducing 
 the motion from that of the cross-head, but we do 
 
RICHARDS' STEAM-ENGINE INDICATOR. 29 
 
 not recommend them ; at high speeds it is very 
 difficult to make them answer. The experience of 
 the careful operator will teach him to guard against 
 the various causes of error here mentioned, and 
 others which will arise in the great diversity of situ- 
 ations in which the Indicator is used, and the 
 effects of which are the more mischievous because 
 often the diagram itself furnishes no means of de- 
 tecting them. The mathematician will perceive 
 that perfect accuracy of motion is attained by only 
 a very few of the methods here suggested. Most 
 of them are only approximately accurate, but they 
 are the best which can be readily employed, and 
 the errors which they involve are too slight to be 
 of practical moment. For the professional engi- 
 neer, of course, directions are unnecessary. 
 
 IIL HOW TO TAKE A DIAGRAM. 
 
 To fix the Paper. Take the outer cylinder off 
 from the instrument, secure the lower edge of the 
 paper, near the corner, by one spring, then bend 
 the paper round the cylinder, and insert the other 
 <x>rner between the springs. The paper should be 
 long enough to let each end project at least half an 
 inch between the springs. Take the two project- 
 ing ends with the thumb and finger, and draw the 
 paper down, taking care that it lies quite smooth 
 and tightj and that the corners come fairly together, 
 and replace the cylinder. 
 
30 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 To connect the Cord. The Indicator having been 
 attached, and the correct motion obtained for the 
 drum, and the paper fixed, the next thing is to see 
 that the cord is of the proper length to bring the 
 diagram in its right place on the paper that is, 
 midway between the springs which hold the paper 
 on the drum. In order to connect and disconnect 
 readily, the short cord on the Indicator is furnished 
 with a hook, and at the end of the cord coming* 
 from the engine, a running loop may be rove in a 
 thin strip of metal, in the manner shown in the 
 following cut, by which it can be readily adjusted 
 
 to the proper length, and taken up from time to 
 time, as it may become stretched by use. On high- 
 speed engines, it is as well, instead of using this, to 
 adjust the cord and take up the stretching, as it 
 takes place, by tying knots in the cord. If the cord 
 becomes wet arid shrinks, the knots may need to be 
 untied, but this rarely happens. The length of the 
 diagram drawn at high speeds should not exceed 
 four and a half inches, to allow changes in the length 
 of the cord to take place to some extent, without 
 causing the drum to revolve to the limit of its mo- 
 tion in either direction. On the other hand, the 
 diagram should never be drawn shorter than is 
 necessary for this purpose. 
 
lUCHARDS' STEAM-ENGINE INDICATOR. 31 
 
 To take the Diagram. Everything being in readi- 
 ness, turn the key of the stopcock to a vertical po- 
 sition, and let the piston of the Indicator play for 
 a few moments, while the instrument becomes 
 warmed. Then turn the key horizontally to the 
 position in- which the communication is opened 
 between the under side of the piston and the 
 atmosphere, hook on the cord and draw the atmos- 
 pheric line. Then turn the key back to its vertical 
 position, and take the diagram. When the key 
 stands vertical, the communication with the cylin- 
 der is wide open, and care should be observed that 
 it does stand in that position whenever a diagram 
 is taken, so that this communication shall not be in 
 the least obstructed. 
 
 To apply the pencil to the paper, take the end of 
 the longer brass arm with the thumb and forefin- 
 ger of the left hand, and touch the point as gently 
 as possible, holding it during one revolution of the 
 engine, or during several revolutions if desired. 
 There is no spring to press the point to the paper, 
 except for oscillating cylinders; the operator, after 
 admitting the steam, waits as long as he pleases 
 before taking the diagram, and touches the pencil 
 to the paper as lightly as he chooses. Any one, by 
 taking a little pains, will become enabled to per- 
 form this operation with much delicacy. As the 
 hand of the operator cannot follow the motions of 
 an oscillating cylinder, it is necessary that the point 
 be held to the paper by a light spring, and instru- 
 
32 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 ments to be used on engines of this class are fur- 
 nished with one accordingly. 
 
 Diagrams should not be taken from an engine 
 until some time after starting, so that the water 
 condensed in warming the cylinder, etc., shall 
 have passed away. Water in the cylinder in ex- 
 cess always distorts the diagram, and sometimes 
 into very singular forms. The drip-cocks should 
 be shut when diagrams are being taken, unless the 
 boiler is priming. If when a new instrument is 
 first applied the line should show a little evidence 
 of friction, let the piston continue in action for a 
 short time, and this will disappear.* 
 
 As soon as the diagram is taken, unhook the 
 cord; the paper cylinder should not be kept in 
 motion unnecessarily, it only wears out the spring, 
 especially at high velocities. Then remove the 
 paper, and minute on the back of it at once as 
 many of the following particulars as you have the 
 means of ascertaining, viz : 
 
 The date of taking the diagram, and scale of the 
 Indicator. 
 
 * Thus, by the motion of the pencil up and down, and the 
 paper from right to left, and left to right, we transfer the 
 pressure of the steam and vacuum (if there be any), and the 
 movement of the piston to the paper, giving us a map or dia- 
 gram of the action required to move the load at any and all 
 points of the stroke, from which the power exerted may be 
 cc mputed and the condition of the internal action seen. 
 
RICHARDS' STEAM-ENGINE INDICATOR. 33 
 
 The engine from which the diagram is taken, 
 which end, and which engine, if one of a pair. 
 
 The length of the stroke, the diameter of the 
 cylinder, and the number of double strokes per 
 minute. 
 
 The size of the ports, the kind of valve employed, 
 the lap and lead of the valve, and the exhaust lead. 
 
 The amount of the waste-room, in clearance and 
 thoroughfares, adds to the length of the cylinder. 
 
 The pressure of steam in the boiler, the diame- 
 ter and length of the pipe, the size and position of 
 the throttle (if any), and the point of cut-off. 
 
 On a locomotive, the diameter of the driving- 
 wheels, and the size of the blast orifice, the weight 
 of the train, and the gradient, or curve. 
 
 On a condensing-engine, the vacuum by the 
 gauge, the kind of condenser employed, the quan- 
 tity of water used for one stroke of the engine, its 
 temperature and that of the discharge, the size of 
 the air-pump and length of its stroke, whether 
 single or double acting, and, if driven indepen- 
 dently of the engine, the number of its strokes per 
 minute, and the height of the barometer. 
 
 The description of boiler used, the temperature 
 of the feed-water, the consumption of fuel and of 
 water per hour, and whether the boilers, pipes, and 
 engine are protected from loss of heat by radiation, 
 and if so to what extent. 
 
 In addition to these, there are often special cir- 
 cumstances which should be noted. 
 2* 
 
34 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 IV. HOW TO KEEP THE INDICATOR IN ORDER. 
 
 Having the attachments made; before we admit 
 steam to the instrument, we open the cocks and 
 blow through the connections to clear them from 
 any foreign matter, that it may not enter and 
 injure the instruments. 
 
 The Indicator will not continue to work well, un- 
 less it is kept in good order. When used, it gene- 
 rally becomes filled with water, which will rust and 
 thus weaken the spring, and the steam often con- 
 tains impurities and grit, a portion of which ia 
 lodged in it. After the Indicator has been used, 
 and before putting it up, unscrew the cover of the 
 cylinder case, and draw off the upper ferule, with 
 the pencil movement and the piston and spring at- 
 tached, empty the water from the cylinder case, 
 carefully clean and dry all the parts, and replace 
 them, lubricating the cylinder with a few drops of 
 oil which is entirely free from gum.* The cylin- 
 
 * The oil is very important; it should be of the purest kind, 
 free from gum and all foreign matter. The porpoise oil we 
 have found to answer all the requirements ; it has wonderful 
 ability to resist the action of steam and water. We have 
 found the cylinder well lubricated after having taken a hun- 
 dred diagrams. It has equal merit in preventing corrosion; 
 hence it should be used on the springs, piston-rod, and arms. 
 It costs high, but a small bottle of it will, if properly used, 
 last for years. It can be obtained of any first-class clock- 
 maker or dealer in clock materials. * 
 
RICHARDS STEAM-ENGINE INDICATOR. 3.^ 
 
 der is not to be removed from the case under any 
 circumstances; the operation above directed gives 
 complete access to it. 
 
 Sometimes the surfaces of the piston and cylinder 
 become scratched or roughened by impurities in 
 the steam, which will be detected at once in the 
 diagram by the unsteadiness of the line. If this 
 shows the existence of any obstruction to the per- 
 fectly free action of the Indicator, take the instru- 
 ment apart, as for cleaning ; take out the two 
 screws at the top of the piston-rod connecting it 
 with the pencil movement, and unscrew the spring 
 from the piston and the cover; then replace the 
 piston in the cylinder, after cleaning and lubri- 
 cating them; screw on the cover to guide the stem, 
 and rub the piston up and down in the cylinder, 
 at the same time revolving the stem between the 
 thumb and finger. The surfaces will quickly wear 
 each other smooth ; no grinding or polishing 
 material should be used; the piston should be taken 
 out once or twice during the operation, and the 
 surfaces cleaned. The piston, if dry, ought to drop 
 perfectly free from every position. Before re- 
 placing, lift the levers, and let them fall, to see if 
 their action also is entirely free. Then replace 
 everything, taking care to screw the heads of the 
 spring firmly up to the piston and cover. Before 
 putting the piston in the cylinder, revolve it be- 
 tween the thumb and finger, to ascertain if the 
 pins connecting it with the pencil movement turn 
 
36 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 quite smoothly in the groove at the end of the 
 stem. The paper cylinder requires to be lubri- 
 cated occasionally with a drop or two of pure oil, 
 applied at the end of the arbor, also the leading 
 pulleys and the joints of the pencil movement. 
 
 V. HOW TO CHANGE THE SPRINGS. 
 
 The directions already given for taking the in- 
 strument apart, for the purpose of smoothing the 
 surfaces of the cylinder and piston, are sufficient 
 also for changing the spring. Merely introduce 
 another, instead of replacing the one removed. 
 The lengths of the springs for the different scales 
 are so proportioned to each other, that the pencil 
 will always come to the proper position for drawing 
 the atmospheric line. Be careful that the heads 
 are screwed up firmly to the piston and cover. 
 
 The spring, which gives reaction to the paper 
 cylinder, is liable to break after considerable use, 
 especially on engines running at high speeds ; 
 for which reason this cylinder should never be left 
 to run unnecessarily. When this happens, a new 
 spring can be readily inserted, as follows. Set the 
 Indicator on the engine; if there is no other con- 
 venient means for holding it firmly, remove the 
 cover of the spring case and the broken spring; 
 then take out the screw, and remove the brass ring 
 from the arbor. Screw the new spring to the 
 brass ring, replace this on the arbor, and set the 
 
RICHARDS' STEAM-ENGINE INDICATOR. 37 
 
 screw firmly up to the head. Then coil the spring 
 into the case, and hook the end on the rim ; see 
 tnat it is coiled in the same direction with the cord. 
 If the spring has not sufficient strength to keep the 
 cord quite tight, another coil must be given to it, 
 but it should not be coiled any tighter than is ne- 
 cessary for this purpose. 
 
 HOW TO ASCERTAIN THE POWER EXERTED BY 
 THE ENGINE. 
 
 The custom was introduced by Watt, and has 
 since been generally followed in England, to desig- 
 nate the size of engines in measures of " horse 
 power." Watt ascertained by experiment that the 
 power of London draught horses, exerted with ordi- 
 nary continuance, was to lift 33,000 Ibs. one foot in 
 one minute, and this is now employed, wherever 
 English measurements are used, as the unit of 
 measurement of the actual power of steam engines. 
 
 The Indicator furnishes one of the data for ascer- 
 taining the power exerted by the steam-engine, 
 namely, the mean or average pressure of steam 
 during the stroke, on each square inch of the 
 piston ; or, more accurately, the excess of pressure 
 on the acting side of the piston to produce motion, 
 over that on the opposite side to resist it. This 
 being multiplied into the whole number of square 
 inches, and the product by the mean or average 
 speed of the piston, in feet per minute, gives the 
 
38 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 total number of pounds of force acting through one 
 foot in a minute, which are called foot pounds, and 
 by dividing this by 33,000, which is the unit for a 
 borse power, we obtain the gross power of the 
 engine in actual horse powers. 
 
 In order to ascertain the effective power, how- 
 ever, there must be deducted from this the friction 
 of the engine, or the power required to drive the 
 engine alone at the same speed, which, except in 
 the case of vessels with the wheels submerged, the 
 Indicator generally enables us to ascertain ; and 
 also the increase in this friction which arises when 
 the resistance is being overcome, which the Indi- 
 cator does not show. The amount of this latter is 
 not generally known with any accuracy ; but we 
 know that the percentage of loss from this cause 
 diminishes as the size of the engine is enlarged, 
 because the increase in the motion of the surfaces 
 in contact is much slower than the increase in the 
 area of the piston, and also that it varies according 
 to the nature of the lubricating material employed, 
 and the degree of completeness attained in the 
 separation of the surfaces by means of it. Five 
 per cent, is usually allowed for this increase of 
 friction; but it may, in fact, be considerably more 
 or less than this. On small engines, the friction- 
 brake can be applied, to show the amount of effec- 
 tive power exerted, and a comparison of this with 
 the gross power, and with the friction of the engine 
 alone, as shown by the Indicator, will exhibit the 
 increase of friction occasioned by different amounta 
 
RICHARDS' STEAM-ENGINE INDICATOR. 3D 
 
 of resistance, and show the value of different lubri- 
 cants, and the utility of extended wearing surfaces. 
 We will now describe the mode of ascertaining 
 from the diagram the mean pressures on the oppo- 
 site sides of the piston, in condensing and in non- 
 condensing engines. For this purpose, divide the 
 diagram into any desired number of equal parts, 
 by lines drawn perpendicular to the atmospheric 
 line. Sometimes these divisions are made very 
 numerous; but the usual practice is to make ten, 
 which number is probably sufficient, unless great 
 accuracy is desired, when twenty divisions may be 
 made. A convenient instrument for facilitating 
 this operation, saving time, and insuring accuracy, 
 is furnished with these Indicators. It consists of a 
 parallel ruler, of eleven bars of thin steel, and a 
 small square. The perpendiculars are first drawn 
 by the square at each end of the diagram, when, 
 the outer edge of bar No. 1 being brought to the 
 beginning, and the inner edge of bar No. 11 to the 
 termination of the stroke, the dividing lines are 
 drawn with a sharp-pointed pencil. If twenty 
 divisions are desired, the intermediate lines for this 
 purpose will also be readily drawn by means of 
 this instrument, points being first marked in the 
 middle of the outer divisions. It is an excellent 
 practice to divide the diagram also by lines drawn 
 parallel with the atmospheric line, into equal 
 divisions, each representing a certain number of 
 pounds pressure, generally five or ten, and num- 
 
40 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 bered on the margin according to the scale of the 
 Indicator ; by which means the engineer is able to 
 observe much more accurately the general nature 
 of the diagram. The same instrument may be 
 employed for this purpose. 
 
 On diagrams from condensing engines, the line of 
 perfect vacuum should be drawn at the bottom, 
 and the line of the boiler pressure, as shown by the 
 gauge, at the top.* The line of perfect vacuum 
 varies in its distance from the atmospheric line, or, 
 more correctly, the latter varies in its distance 
 from the former, according to the pressure of the 
 atmosphere, as shown by the barometer, from 
 13 . 72 Ibs. on the square inch when the mercury 
 stands at 28 inches, to 15 . 19 Ibs. when it stands at 
 31 inches (vide Table II.); and it should be drawn 
 according to the fact, if this can be ascertained. 
 The engineer should always have a good aneroid 
 in his pocket. The pressure of the atmosphere is 
 usually reckoned at 15 Ibs., which, as a general rule, 
 is too high, being correct only when the barometer 
 stands at 30.6 inches ; but the error is unimpor- 
 tant, and it is very convenient to avoid the use of 
 a fraction, and to say that 30 Ibs., 45 Ibs., 60 Ibs., 
 
 * When accuracy is required, the steam-gauge should be 
 tested by the Indicator, which may be done by stopping the 
 engine on the centre, opening the steam-valve, and letting 
 the full pressure on the instrument; when the indications of 
 the two instruments may be compared and noted. 
 
41 
 
 and so on, represent 2, 3, 4, 5, 6 atmospheres of 
 pressure. 
 
 The principal object of knowing the exact pres- 
 sure of the atmosphere is, to ascertain the duty 
 performed by the condenser and air-pump. The 
 temperature of the discharge being known, the 
 pressure of vapor inseparable from that tempera- 
 ture is also known (vide Table No. HI.), and this 
 being deducted from the actual pressure of the 
 atmosphere, the remainder is the total attainable 
 vacuum at that temperature. 
 
 The areas of the diagram above and below the 
 atmospheric line are usually calculated separately, 
 to ascertain how effectually the resistance of the 
 atmosphere is removed from the non-acting side of 
 the piston, by those parts of the engine whose func- 
 tion this is. In case of engines working very ex- 
 pansively, however, the expansion curve crosses 
 the atmospheric line, and sometimes at an early 
 point of the stroke, as in diagram No. 10. In such 
 cases, the whole space between the atmospheric 
 line and the line of counter-pressure should be 
 credited to the condenser and air-pump ; not, of 
 course, to be considered in estimating the power 
 exerted, but for ascertaining the degree of economy 
 in the consumption of steam, which depends greatly 
 on the amount of vacuum maintained. 
 
 The lines having been accurately drawn as above 
 directed, ascertain, by careful measurement with 
 the scale, the mean pressure in each division, be- 
 
42 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 tween the atmospheric line and the upper line of 
 the diagram, until this crosses the former, if it does 
 so; add these together, and point off one place cf 
 decimals, or divide their sum by the number of 
 divisions, if there are more than 10, and the quo- 
 tient will be the mean pressure above the atmos- 
 phere during the stroke. Then repeat the process 
 for the area between the atmospheric line, or the 
 expansion curve after it has crossed this line, and 
 the lower outline of the diagram. Add the two 
 mean pressures so ascertained together, then find 
 in Table No. I. the number of square inches in the 
 surface of the piston, if you know the diameter, 
 and multiply the pressure on one square inch by 
 the number of square inches, and the product by 
 the mean velocity of the piston, in feet per minute, 
 and divide by 33,000, and the quotient will be the 
 gross amount of horse-power exerted ; or the 
 power represented by the two areas of the dia- 
 gram, above and below the atmospheric line, may 
 be calculated separately. 
 
 [Since the publication of the First Edition, my attention 
 has been called to an improved method of measuring the dia- 
 gram which is more expeditious and less liability to error. ] 
 
 Thus, your diagram is divided into equal parts as 
 usual sa y 10. Now, we take a narrow 'slip of paper, 
 or what is better, card-board that is thin and smooth; 
 this we place across the diagram as we would the 
 scale, letting the end of it be exactly over the base 
 line ; then with a sharp-pointed knife prick the slip 
 
EICHARDS' STEAM-ENGINE INDICATOR. 43 
 
 40* 
 
 exactly over the line opposite the base (steam-line), 
 advance the slip to the next division, and carrying 
 the point made by the knife to the base line, then 
 remove the knife and make another prick exactly 
 over the line opposite. Repeat the movement until 
 you have measured each space ; then make a mark 
 with your pencil. Now, with a rule, you measure 
 the distance from the end of the slip to your pencil 
 mark ; we will assume that it is 6J inches. Now, as 
 you have measured 10 spaces, to get the average, we 
 divide it by 10 ; thus, 6J expressed decimally is 6.25. 
 This, divided by 10, is equal to .625. 
 
 Now the scale of the diagram we will assume to be 
 40 to one inch. We then multiply .625 by the scale, 
 which we have assumed to be 40, and we get the fol- 
 lowing result as an average pressure per square inch : 
 
 .625 
 40 
 
 25.000 Ibs. pressure. 
 
 Expressed in arithmetical signs, it is 
 
 6.25 -=- 10 = .625 x 40 = 25.000. 
 
 Should there be more or less than 10 divisions of 
 the diagram, divide by the number, whatever it is. 
 Should the scale of the instrument be other than 40, 
 then multiply by the number, whatever it may be. 
 
 This mode is much less liable to error than the 
 ordinary mode ; in fact, it reduces the liability as ten 
 to one. It is more expeditious, in so much as it saves 
 the additions of a long column of figures. 
 
 The space between the steam line and the line of 
 boiler pressure shows how much the pressure is 
 
44: RICHARDS' STEAM-ENGINE INDICATOR. 
 
 reduced in the cylinder by throttling, or by the in- 
 sufficient area of the ports, proper allowance being 
 made for the difference of pressure necessary to 
 give the rapid motion to the steam, and that be- 
 tween the line of counter-pressure and the line of 
 perfect vacuum shows the amount of resistance to 
 the motion of the piston. 
 
 In illustration of the foregoing directions, let it 
 be required to find the effective power exerted by 
 the pair of engines, from the upper end of one of 
 which diagram No. 1 was taken, the diameter of 
 cylinder being 95", the stroke of the piston 10', and 
 the number of revolutions 15 per minute. We will 
 assume that the other engine would have given the 
 same diagram, which is possibly correct, and also 
 that the lower ends of the cylinders would have 
 given the same, which is probably quite incorrect, 
 because in side-lever, or beam engines, the speed of 
 the piston at the lower end is slower, and therefore 
 probably the pressure obtained is greater, than in 
 the upper end, the motion of the valves being the 
 same. 
 
 The mean pressure of steam above the atmosphere 
 
 was 9.82 Ibs. 
 
 The average vacuum was 11 .4.6 " 
 
 Total excess of pressure above the resistance was. 21.28 " 
 
 The better mode of calculation in all cases is, to 
 obtain first the number of horse-powers for 1 Ib. to 
 mean pressure on the square inch, as follows : 
 
RICHARDS* STEAM-ENGINE INDICATOR. 45 
 
 Multiply the number of square inches in the 
 
 surface of the piston 7088 . 2 
 
 By the speed of the piston in feet per minute. 300 
 
 33. (000)2126(460. 0(61 44 
 198 
 146 
 132 
 144 
 132 
 "126 
 
 Which is the number of horse-powers exerted, for 
 each pound of pressure during the stroke on 1 square 
 
 inch of the piston 64.44 
 
 To obtain the gross power we multiply this by the 
 
 average pressure per square inch on the piston 21 .28 
 
 "51552 
 
 12888 
 
 6444 
 12888 
 Gross horse-powers exerted in one engine .... 1371 .2832 
 
 To obtain the effective power we must ab- 
 stract from the multiplier 21 . 28 Ibs. 
 
 The pressure required to run the engine 
 alone, which in so large an engine 
 would probably not exceed 1 .00 Ib. 
 
 And the increase in this pressure required 
 to overcome the increased friction when 
 the resistance is being overcome, say 5 
 
 per cent =1.06 " 
 
 2.061ba 
 
 Effective pressure on each square inch .... 1& . 22 " 
 
 Which multiplied by 64.44 
 
 7688 
 7688 
 7688 
 11532 
 
 Gives amount of effective horse-power ... 1238.5368 
 Which multiplied by 2 
 
 Gives 2,477.0 horse- 
 power as the effective power of the engines. 
 
4(5 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 It will be observed that, by the above mode of 
 calculation, we obtain for any engine, the speed of 
 piston continuing the same, a constant number, 
 which, multiplied by the mean pressure on a square 
 inch, gives at once the amount of horse-power 
 exerted at any time. 
 
 On diagrams from non-condensing engines, the line 
 of boiler pressure should be drawn at the top, and 
 it is well to draw the line of perfect vacuum also, 
 that the engineer may be able to see at a glance the 
 quantity of steam consumed, and to compare with 
 it the amount of work done. It is not possible that 
 the back pressure resisting the motion of the piston 
 shall be less than the pressure of the atmosphere, 
 but it may be a great deal more, and very commonly 
 in non-condensing engines the line of resistance is 
 as much as 2 or 3 Ibs. above the atmospheric line, 
 though it is quite possible to avoid this excess 
 altogether, as is shown in diagrams Nos. 6 and 9. 
 
 The mean pressure is ascertained in the manner 
 already directed for obtaining the pressure in con- 
 densing engines above the atmospheric line, and 
 the power is calculated in the same way. 
 
 For example, let it be required to find the effec- 
 tive power exerted by the engine from which 
 diagram No. 6 was taken, the diameter of the cyl- 
 inder being 18", the stroke of the piston 42", and 
 the number of revolutions 60 per minute 
 
BICHAKDS STEAM-ENGINE INDICATOR. 47 
 
 The mean pressure of steam during the 
 stroke, above the resistance of the at- 
 mosphere, was 25 Ibs, 
 
 From this we must subtract the pressure 
 required to run the engine alone, say. . 1.75 Ibs. 
 
 And the increase of pressure required to 
 overcome the increased friction when 
 the load is on, estimated at 5 per cent. . 1.25 " 
 
 3 Ibs. 
 
 Leaving effective pressure 22 " 
 
 The area of the piston is 254.5 square inches, 
 
 Which, multiplied by the velocity of 
 the piston 420 feet per minute, 
 
 50900 
 10180 
 
 And divided by 33. (000)106(890.0(3. 24 
 99 
 
 78 
 
 129 
 132 
 
 Gives 3.24 horse-powers, for 
 each pound of pressure on 
 1 square inch during the 
 
 stroke 3.24 horse-powers, 
 
 Multiplied by 22 Ibs. pressure, 
 
 648 
 648 
 
 Gives 71 . 28 effective horse-powers, 
 
 assuming the pressure on the opposite side of the 
 piston to have been the same. 
 
48 RICHARDS STEAM-ENGINE INDICATOR. 
 
 In the same manner, on stationary engines, the 
 power shown by the frictional diagrams can be 
 calculated, and by diagrams taken when the shaft- 
 ing only is being driven, and when greater or lesser 
 proportions of the whole resistance are being over- 
 come, and on vessels at different depths of immer- 
 sion. 
 
 Generally, engines will give the same figures at 
 each revolution, the pencil retracing the same line 
 so long as the resistance continues the same ; but 
 sometimes this is not the case, as in the engine 
 from which the diagram just calculated was taken, 
 where are shown four distinct expansion curves. 
 In such cases care must be taken to obtain the 
 average diagram. Also, in comparing the pressures 
 required to overcome different resistances, it is es- 
 sential that the speed of the engine in each case be 
 the same, a requirement often disregarded. 
 
 In all calculations of power from the diagram, it 
 is assumed, and correctly so, that the value of each 
 unit of motion of the piston is the same, whether 
 measured at the extremes or in the middle of the 
 stroke. The motion of the crank should be uni- 
 form; and if this is the case, the divisions of the 
 time occupied in a revolution can be accurately 
 measured on the circle which it describes. The 
 motion of the piston, on the contrary, changes at 
 every point of the stroke. At the instant when the 
 crank is on the centre it is at rest; then its speed, 
 at first infinitely slow, becomes gradually acceler^ 
 
RICHARDS STEAM-ENGINE INDICATOR. 3 
 
 ated, until, at the point where the direction of mo- 
 tion of the piston and that of the crank-pin coin- 
 cides, the velocities of the two are equal, and for 
 some distance before reaching and after passing 
 this point they differ but little ; then its motion is 
 gradually retarded, until on the opposite centre it 
 is at rest again. 
 
 TO MEASURE FROM THE DIAGRAM THE AMOUNT 
 OF STEAM CONSUMED. 
 
 For this purpose, draw the line of perfect vacu- 
 um, if not precisely known, at 14.7 Ibs. below the 
 atmospheric line. Ascertain how much the clear- 
 ance and the thoroughfare add to the length of the 
 cylinder at one end, and add a proportionate quan- 
 tity to the length of the diagram by a line drawn 
 perpendicular to the atmospheric line, at the proper 
 distance from the admission line. Then ascertain 
 the point in the stroke at which the steam is 
 released, and the pressure in the cylinder at that 
 point. Multiply this pressure, reckoned from the 
 line of perfect vacuum (and which must be taken 
 before the exhaust-port has been opened), by the 
 sectional area of the cylinder in square inches, and 
 the product by the length of the stroke in inches, 
 up to the point at which the steam was released, 
 and including the addition for the clearance and 
 thoroughfare, and divide by 14.7, and the quotient 
 will be the number of cubic inches of steam, at the 
 
60 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 pressure of the atmosphere, discharged from the 
 cylinder at a single stroke. If the valves do not 
 leak, and there is no water with the steam, the cubic 
 contents of the cylinder multiplied by the pressure, 
 at the point of cut-off, should equal the cubic con- 
 tents multiplied by the pressure, at the point of 
 release, and in a compound engine the cubic con- 
 tents of each cylinder multiplied by the pressure, 
 at the point of release, should give the same result. 
 Multiply this by the number of strokes in an hour, 
 and divide the product by 1728 to reduce the cubic 
 inches to cubic feet, and the quotient again by 1700, 
 to reduce the steam at atmospheric pressui a to 
 water, and the result will be the number of cubic 
 feet of water used per hour; multiply this by 62.5 
 for pounds, and divide the product by 8.33 Ibs. for 
 wine gallons. The supply of water to the boilers 
 will need to be greater than the quantity thus ascer- 
 tained, and the excess required will measure the 
 aggregate loss from all causes, including leakage, 
 priming, blowing off, and radiation from the cylin- 
 der and pipes where the water of condensation does 
 not flow back into the boiler. It is essential, of 
 course, that the diagram measured shall represent 
 the uniform power exerted, or the mean power, if 
 it is subject to variations. 
 
 The detection in this manner of losses of heat, 
 
 from occult causes, is one of the most remarkable 
 
 and important services which have been rendered by 
 
 the Indicator. It has been proved in some cases 
 
 3 
 
RICHARDS' STEAM-ENGINE INDICATOR. 51 
 
 that nearly or quite twice the volume of steam 
 must have entered the cylinder at every opening 
 of the ports, either in the form of steam or of water 
 already condensed, that existed in the form of 
 steam at the point of cut-off. The field here pre- 
 sented is one of the most useful in which the Indi- 
 cator can be employed. 
 
 OBSERVATIONS ON THE SEVERAL LINES OF THE 
 DIAGRAM. 
 
 In order to point out clearly the principal points 
 of excellence and defect in the action of engines, 
 which are made known by the Indicator, it will be 
 best to consider each line of the diagram separately, 
 beginning at the commencement of the stroke. . 
 
 I. THE ADMISSION-LINE. 
 
 At low pressures of steam this line may be very 
 nearly vertical, especially when the opening of the 
 ports is preceded by considerable compression of 
 the steam in the cylinder, as in diagram No. 1. 
 Diagram No. 13, also taken from a celebrated 
 steamship, shows a more gradual opening, but not 
 preceded by any compression. At high pressures 
 it is important to avoid the shock of the full force 
 of the steam on the centre, especially when there 
 has been no compression. Diagrams Nos. 6 and 7, 
 from non-condensing engines, show a moderate 
 advance of the piston, and, the former especially, a 
 
52 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 
 
 considerable movement of the orank, while the pres- 
 sure was being attained in the cylinder, the latter 
 with and the former without precedent compres- 
 sion. These are all excellent admission-lines. 
 
 The direction of this line is determined by the 
 amount of lead given to the valve, for which no 
 general rule can be laid down. It depends upon 
 the speed of the piston, the proportion between the 
 area of the ports and that of the cylinder, the 
 rapidity or slowness of the opening movement, and 
 the density of the steam already in the cylinder at 
 the instant of opening. The proper lead can be 
 ascertained only by the application of the Indica- 
 tor. Without its assistance the best judgement is 
 liable to err in a case presenting novel conditions. 
 By the best judgment is meant a judgment formed 
 by careful comparison of the lead given with the 
 admission-line drawn by the Indicator, in a wide 
 diversity of cases. 
 
 II. THE STEAM-LINE. 
 
 Here we find engines divided into four classes, 
 namely 
 
 1. Those in which the valves have an invariable 
 motion, without any or with only very trifling lap, 
 causing the port to remain open, or, technically, 
 the steam to follow the piston, quite or nearly to 
 the envl of the stroke. 
 
lUCHAKDS' STEAM-ENGINE INDICATOR. 53 
 
 2. Those in which the valves have also an in- 
 variable motion, but with more or less lap, causing 
 the steam to be cufc off at a certain fixed point of 
 the stroke. 
 
 3. Those in which the point of cut-off may be 
 varied by hand, either by means of the link motion 
 or of an independent cut-off gear; and, 
 
 4. Those in which the point of cut-off is adjusted 
 by the action of the governor, according to the 
 changes either in the pressure of steam or the re- 
 sistance to be overcome. 
 
 In the first two classes, when less than the full 
 pressure is required in the cylinder, the governor 
 or the engineer adjusts the pressure by changing 
 the position of the regulating valve. In the third 
 class the regulating valve may be employed for this 
 purpose, but the more usual and better way is to 
 run such engines with this valve entirely open, and 
 to adjust the mean pressure in the cylinder by 
 changing the point of cut-off. Engines of the fourth 
 class have no regulating valve, but the full attain- 
 able pressure of steam is admitted to the cylinder. 
 
 The action of the regulating valve varies the po- 
 sition of the steam line upward or downward, to 
 that distance from the atmospheric line which gives 
 the mean pressure required. The action of the 
 cut-off gear, on the contrary, varies its length for 
 the same purpose. In engines in which the steam 
 follows to the end, or nearly to the end, of the 
 
51 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 stroke, and indeed in all cases where the pressure 
 is reduced between the boiler and cylinder by the 
 action of the regulating valve, it is a matter of very 
 little interest what the steam-line may be. Not 
 only its distance from the atmospheric line, but 
 also its direction, is changed by every change in 
 the position of the regulating valve, so that it is 
 not at all a fit subject for consideration. 
 
 In engines which have no regulating valve, or 
 where it is not employed, as in marine engines ex- 
 cept in rough weather^ the steam -line should ap- 
 proach nearly to the line of boiler pressure, and 
 should be parallel with this line up to the point of 
 release or cut-off. Diagrams Nos. 1, 6, 8, 9, afford 
 examples of correct steam-lines, except that in No. 
 1 it is not continued parallel nearly up to the point 
 of cut-off. Diagram No. 10 shows a slight fall of 
 the steam-line as the piston advanced, but the 
 point of cut-off is well shown. Diagram No. 12 
 from a marine condensing engine, at 336 feet travel 
 of piston per minute; and Nos. 2, 3, 4, and 5, from 
 a locomotive, at 730, 820, and 950 feet travel of pis- 
 ton per minute, afford, on the contrary, examples 
 of bad steam-lines. The boiler pressure is very near- 
 ly attained at the commencement of the stroke, in 
 the first case, by lead given to the valve, and in 
 others by lead superadded to excessive compres- 
 sion ; but as the piston advances, the pressure falls 
 with great rapidity, and the point at which the 
 port was closed there is no means of discovering. 
 
RICHARDS' STEAM-ENGINE INDICATOR. 55- 
 
 In all these cases the passage of steam to the valve- 
 chamber was entirely unimpeded. Diagrams Nos^ 
 15 and 16 are good admission and steam lines. 
 Locomotive -diagrams Nos. 19, 20, and 21, are re- 
 markably good steam and admission lines. In No. 
 22, steam-line falls off slightly. The nature of 
 the steam-line depends principally on the propor- 
 tion between the area of the ports, supposing them 
 to be, as they ought, the smallest passages through 
 which the steam is taken, and the cubical capacity 
 of cylinder to be filled in a given time. A given 
 cubical capacity may be formed in the same time- 
 by the slow advance of the piston in a larger cylin- 
 der, or by its more rapid advance in a smaller one. 
 The sectional area of cylinder and the speed of the 
 piston must be equally considered in determining" 
 the area of the ports, as they are equal elements irt 
 determining the capacity of cylinder to be filled. 
 
 While, therefore, very high velocity of piston 
 does not render impossible the attaining of a cor- 
 rect steam-line, still the size of port required for 
 this purpose becomes so considerable, and the- 
 amount of power absorbed in working the valves, 
 under the pressure which is generally associated 
 with high speed of piston, is already so serious, that 
 with the present form of valve in use on locomo- 
 tives, for example it is better probably to submit 
 to the defect at high velocities, than to attempt to 
 mend it by enlargement. Improvement in this fea- 
 ture can be looked for only from a radical change 
 
RICHARDS STEAM-ENGINE INDICATOR. 
 
 in the valves and movements. It should be ob- 
 served, however, that the velocity of piston at 
 which diagrams Nos. 7 and 8 were drawn was 600 
 feet per minute. Another cause often contributes 
 largely to injure the steam-line, especially in con- 
 densing engines namely, the condensation of the 
 steam on entering the cylinder ; and to this the 
 enormous fall of pressure in diagram No. 11 must 
 undoubtedly be in part attributed, the smallness 
 of the ports not being sufficient to account for it. 
 
 There is obviously a point beyond which expan- 
 sion can not be advantageously carried, because it 
 is possible to cut the steam off so early that even 
 with the highest pressure the engine will not per- 
 form any duty at all, but only run itself. Of course 
 the power absorbed in running the engine should 
 be only a small percentage of the gross power ex- 
 erted. But there is also another limitation. The 
 loss of heat by radiation and conduction, external 
 and internal, is far greater than was till lately gen- 
 erally supposed. It is possible to protect pretty 
 thoroughly against external radiation ; but against 
 internal radiation, which is so much greater than 
 the other, as the capacity for heat of the exhaust 
 steam, at the density it may have, is greater than 
 that of the atmosphere, it is not possible to protect 
 at all, and the earlier the steam is cut off, the 
 greater is the proportionate time during which the 
 exposed surfaces are being cooled, and the smaller 
 the quantity of steam admitted from which they 
 
RICHARDS' STEAM-ENGINE INDICATOR. 57 
 
 must be warmed again.* The phenomenon of a 
 higher terminal pressure, in cylinders working 
 steam expansively, than the law of the gases could 
 account for, was generally explained, until quite re- 
 cently, by supposing that the valves leaked ; but 
 when it was found to be universal, and to be most 
 remarkable where the steam was most charged 
 with moisture, thoughtful men were not long in de- 
 tecting the true cause. The temperature of this 
 moisture, as it enters the cylinder, is the same as 
 that of the steam, and being in great part relieved 
 from pressure by the expansion, it will instantly 
 assume the gaseous form, provided the heat, which 
 must be rendered latent on its change of state, is 
 furnished. This is abstracted from the surfaces 
 with which the particles of moisture come in con- 
 tact, and the excess of terminal pressure above 
 that which should exist measures the heat thus 
 lost, and which must be regained at the commence- 
 ment of the next stroke from the entering steam. 
 If the steam enters the cylinder nearly dry, this 
 process, when the cylinder becomes heated, soon 
 reaches a very moderate point, as is illustrated in 
 diagram No. 6, where the theoretical curve is closely 
 approximated to. Diagrams No. 7 and 8, on the 
 
 * The recent experiments of Professor Tyndall reveal the- 
 astounding fact, that the power of aqueous vapor, at the 
 pressure of the atmosphere, to absorb heat, is 6,000 timea 
 greater than that of dry air. 
 
58 RICHARDS* STEAM-ENGINE INDICATOR. 
 
 contrary, being taken at the Great Exhibition of 
 1862, where the steam was charged with moisture 
 In an excessive degree, show a great amount of 
 re-evaporation to have taken place, as the pressure 
 fell in the cylinder. 
 
 The best means at present known for diminish- 
 ing the loss from this cause is, to dry the steam by 
 moderate superheating, perhaps sufficient to affect 
 -the thermometer but very slightly, since every atom 
 of moisture must change its state to steam before 
 ihe temperature can rise above that due to the 
 pressure. The height of the terminal pressure, as 
 ^shown by the Indicator, above that which the law 
 of Mariotte and the law of contraction of gases by 
 -cooling call for, affords some indication of the loss 
 from this cause. If the curve drawn could agree 
 with the requirements of these laws, there would 
 &e demonstrably no loss at all ; but this is not at- 
 tainable. Indeed, the higher temperature of the 
 .cylinder would probably affect sensibly the fall of 
 pressure, even if the steam was perfectly anhydrous. 
 It is obvious, that the percentage of loss will be 
 diminished, other circumstances being the same, in 
 proportion as the speed of piston is increased, the 
 actual loss continuing the same, but the power ex- 
 erted becoming greater. Whether the employment 
 of two cylinders enables this loss to be avoided to 
 a greater extent than it can be in a single cylinder, 
 must at present be regarded as an open question, 
 3* 
 
RICHARDS STEAM-ENGINE INDICATOR. 59 
 
 and is one the discussion of which is foreign to the 
 purpose of this work. 
 
 To expand steara properly, it is essential that it 
 be cut off instantaneously that is, that the port 
 shall be closed so quickly, that the pressure shall 
 not fall in the cylinder, from the advance of the 
 piston during the operation of closing. This Indi- 
 cator enables us to pronounce unerringly upon the 
 value of every means which is employed to effect 
 this object. 
 
 Diagram No. 6 shows unquestionably the closest 
 approximation to this requirement. It was taken 
 from an engine in the city of New York, of the cel- 
 ebrated style known as the Corliss Engine, which 
 is extensively used in the eastern part of the Uni- 
 ted States for stationary purposes. The speed of 
 piston of this engine was 420 feet per minute. 
 
 Diagrams 9 and 13 show the cut-off made by the 
 Sickels valve-gear, also in extensive use in the 
 United States, especially on boats and vessels. No 
 9 was taken from a non-condensing stationary en- 
 gine, making 30 revolutions per minute, and No. 
 13 from the engines of a steamship at 16 revolu- 
 tions per minute. It is hardly necessary to add 
 that these were not taken with the Eichards Indi- 
 cator. The theoretical expansion curves cannot 
 be drawn on either of these diagrams, because the- 
 amount of waste room, which is considerable, from 
 the nature of the valves employed, is not known. 
 
<<50 RICHARDS STEAM-ENGINE INDICATOR. 
 
 The speed of piston in each was about 300 feet per 
 minute. 
 
 Diagrams Nos. 7 and 8 were taken from the Al- 
 len Engine at the Great Exhibition of 1862, at a 
 rspeed of piston of 600 feet per minute. The pres- 
 sure fell somewhat at this great speed, as the clos- 
 ing movement of the valve was being completed, 
 -giving a rounded corner. In Diagram No. 7 we 
 iind the expansion curve changed to a waving line. 
 The pressure of steam was removed from the pis- 
 ^on of the Indicator with such extreme suddenness 
 that the reaction of the spring was necessarily vio- 
 lent; but the rounded, flowing nature of the oscil- 
 lations show the action of the instrument to have 
 "been frictionless, and these gradually subside into 
 ~the correct curve, which the mean of the oscillations 
 gives throughout, as shown. Diagram No. 10, 
 -from the engines of a steamship, shows very su- 
 perior action of the cut-off gear. 
 
 The vice which is the opposite of this excel- 
 lence is technically termed wiredrawing, and con- 
 sists in a gradual fall of pressure in the cylinder, 
 "while the port is being closed. It is illustrated in 
 -various degrees in several of these diagrams, and is 
 41 source of serious loss. The object of cutting off 
 is, to obtain the greatest mean pressure with the 
 lowest terminal pressure, and it is clear that the 
 sharper the cut-off the more completely this object 
 is attained. For example, in diagram No. 1, the 
 fiteam expands to a pressure of 17 Ibs. at the point 
 
RICHARDS' STEAM-ENGINE INDICATOR. 61 
 
 of release, and a mean pressure of 21.28 Ibs. is 
 exerted during the stroke ; had it been cut off 
 sharply at the point c, it would have expanded to a 
 pressure of 9 Ibs. at the point of release, describing 
 the curve c g, and would have exerted a mean pres- 
 sure of 15.87 Ibs. But 21.28 : 15.87 : : 17 : 12.67. 
 The gain of steam from cutting off sharply would 
 be then 12.67 - 9=3.67 Ibs., or 29 per cent. But 
 this is by no means the full amount of the gain, for 
 so much less steam being to condense, 1 Ib. better 
 vacuum at least would have been formed, and the 
 boilers would easily have maintained a pressure 5 
 Ibs. higher, with much more moderated firing ; so 
 that the full mean pressure of 21.28 Ibs. would have 
 been obtained by cutting off at the point c, and 
 expanding to a terminal pressure of 10.5 Ibs., a gain 
 of J5 Ibs., or 38 per cent., and improvements equal 
 to this have by this single means been often real- 
 ized in practice. The slide-valve in its best form 
 wiredraws the steam considerably, unless a great 
 travel is given to it; the vicious practice of making 
 the end V-shaped of course raises the loss from this 
 cause to the very highest point. 
 
 Diagram No. 14 shows the action of a single 
 slide-valve with a serrated end, expressly contrived 
 to wiredraw the steam as much more than it can be 
 with the ordinary slide as possible. 
 
 The mean pressure for different points of cut-ofij 
 may be found by 
 
62 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 HYPERBOLICAL LOGARITHMS. 
 
 RULE. Divide the length of the stroke by the 
 length of the space into which the steam is admit- 
 ted; find in Table No. IV. the logarithm of the 
 number nearest to the quotient, to which add 1, the 
 sum is the ratio of the gain; then find the terminal 
 pressure, by dividing the initial pressure by the 
 proportion of the stroke during which the steam is 
 admitted, and multiply it by the logarithm -J- 1, 
 found as above; the product will be the mean pres- 
 sure through the stroke. 
 
 EXAMPLE. Suppose the length of the stroke to 
 be 48 inches, the initial pressure to be 40 Ibs. per 
 square inch, and the steam to be cut off at 12 inches 
 of the stroke, what will be the mean pressure ? 
 
 48^12=4. Hyp. log. of 4=1.38629+1=2.38629. 
 
 Then, 40 -^ 4 = 10 X 2.38629 = 23.8629 Ibs., the 
 mean pressure required. 
 
 To find the initial pressure, add the atmospheric 
 pressure, 15 Ibs., to the pressure shown by the gauge, 
 and from the mean pressure found as above sub- 
 tract the counter-pressure, to ascertain the actual 
 mean pressure exerted. Thus, in the above case, 
 the gauge is supposed to show a pressure of 25 Ibs. 
 only, and if the calculation is being made for a con- 
 densing engine, the estimated loss from imperfect 
 vacuum must be subtracted, and if for a non-con- 
 densing engine, the pressure of the atmosphere, 
 and also any estimated counter-pressure above that, 
 
63 
 
 must be subtracted from 23.8629, the mean pressure 
 found by the calculation. 
 
 The editor remarks that the above rule requires 
 a little qualification, to be considered correct. If 
 the diagram shows the cut-off at J of the stroke, it 
 does not follow that | is the grade of expansion, be- 
 cause the clearance has not been taken into account. 
 
 EXAMPLE. Suppose the length of the stroke to 
 be 36"; initial pressure, to be 50 Ibs. per square 
 inch, and the steam to be cut off at 9" of the stroke, 
 what will be the average pressure ? 
 
 36-^-9=4. Hyp. Log. of 4=1.38629+1=2.38629. 
 Then 50-1-4=12.5X2.38=29.75, mean pressure 
 required. This is correct without taking the clear- 
 ance into account. 
 
 Now, let us see what the result is, when we add 
 the clearance in the following examples; which is 
 an actual case occuring in my practice during the 
 week in which this was written. 
 
 Engine 36" strokeXl^" diameter, cutting off at J 
 (9") ; initial pressure 50 Ibs. to the square inch ; 
 revolutions per minute, 80 ; clearance equal to -fa 
 of the cubical contents of the part of the cylinder 
 occupied by the piston stroke ; or what is the same 
 thing, -fa of the stroke, which is equal to 1.64", 
 added to 9", the point of cut-off, is 10.64" ; which 
 being divided by the length of the stroke, gives us 
 as a quotient 3.39, with a mean pressure of 32.59 
 Us., as calculated by the above rule, adding the 
 clearance. 
 
64 RICHARDS* STEAM-ENGINE INDICATOR. 
 
 Computing it by the same rule, without taking 
 account of the clearance, the average pressure is 
 29.75 Ibs. The result stands thus, computing with 
 
 the clearance added 73.00 H. P. 
 
 Without the clearance 66.64 " " 
 
 Difference 6.36 
 
 In using Table No. V., the clearance must be 
 added to get the correct mean pressure. 
 
 IV. THE EXHAUST LINE AND THE LINE OF COUNTER- 
 
 may properly be considered together. It is, of 
 course, desirable that the pressure of the steam be 
 got rid of as completely as possible before the 
 piston commences its return stroke. This is 
 accomplished in a non-condensing engine by having 
 the exhaust port and passages sufficiently large, and 
 opening the port a sufficient time before the termi- 
 nation of the stroke, according to the density of the 
 steam to be released and the velocity of the piston. 
 The passages and pipes communicating with the 
 atmosphere should be at least 50 per cent, larger 
 than the ports, and as free from angles as possible. 
 
 These requirements apply to condensing engines 
 even more strongly, and in addition the condenser 
 and air-pump must be able to maintain a proper 
 ' vacuum. 
 
 Diagrams Nos. 6 and 9 show no back-pressure at 
 
RICHARDS' STEAM-ENGINE INDICATOR. 65 
 
 all above the atmosphere ; diagrams Nos. 7 and 8 
 show a trifling back-pressure, attributable to the 
 number of angles in the pipe necessary for connect- 
 ing with the exhaust main at the Exhibition. 
 
 Diagram No. 10 exhibits remarkable exhaust and 
 counter-pressure lines, obtained by a surface con- 
 denser, while No. 13 shows a great loss of power 
 from imperfect vacuum, which was very partial at 
 the best, and that only gradually obtained. 
 
 V. THE COMPRESSION-LINE. 
 
 This line, when it exists, is formed by the closing 
 of the exhaust port at some point before the termi- 
 nation of the stroke, when the advancing piston 
 compresses the confined steam to a density propor- 
 tioned to the decrease of volume. This is illustrated 
 in various degrees in several of the diagrams here 
 shown. This action occasions a loss of power, but 
 not much waste of stream, because the confined 
 steam reacts on the return stroke with a force equal 
 to that expended to compress it. It is useful on 
 engines running at high velocities, by taking up 
 gradually all looseness of the joints, and prevent- 
 ing the entire force of the steam from striking 
 suddenly on the piston. Indeed, so important is 
 the compression in preventing shocks on the centres 
 in engines of this class, that probably locomotives 
 could not be safely run without it. At the same 
 time, the nature of the valve and gear employed on 
 
66 BICHAKDS* STEAM-ENGINE INDICATOR. 
 
 this class of engines is such, that when cutting off 
 very early the compression becomes excessive, 
 involving an increase in the counter-pressure as 
 the piston approaches the centre, which is quite 
 unnecessary for any useful purpose, as is illustrated 
 especially in diagram No. 4. At any ordinary 
 number of revolutions per minute made by station- 
 ary or marine engines, the compression is not 
 required, but in a moderate degree is never, 
 perhaps, objectional.* 
 
 * We do not think our author gives sufficient prominence 
 to the advantages of compression ; all engines require it, to a 
 greater or less degree, depending, of course, on the speed and 
 action of the valves. Our practice is, when we can control 
 the exhaust valves, to compress from one-half to the whole 
 initial pressure. A great point gained by compression is, to 
 take up and store away, to assist on the return stroke the 
 momentum of the piston and its connections with the crank ; 
 also, to fill the ports, passage-ways and clearance with exhaust 
 steam, that we may not have to call on the boiler for it. It is 
 certainly easier on the machine to take up slack motion of the 
 joints thus gradually, than to take high steam on before 
 reaching the centre. It is true, we reduce the capacity of the 
 cylinder, but lose no steam ; on the contrary, save the momen- 
 tum of the reciprocating parts, by compressing a portion of 
 the exhaust steam. When the slide-valve is used, it serves 
 to partially balance it during the compression, thereby reliev- 
 ing it from friction and wear ; a very important consideration, 
 particularly on large valves. We prefer also to give very little 
 or no steam lead; let the centre be past or nearly so, and the 
 piston on its way back, before the steam is admitted. 
 
 Many a crank and its connections have been broken, brasses 
 
RICHARDS' STEAM-ENGINE INDICATOR. C7 
 
 Diagram No. 12, not taken by the Richards Indi-. 
 cator, shows the usual form of diagram made by the 
 double opening slide-valves now in general use on 
 marine engines, with an independent cut-off valve. 
 It will be observed, that the steam line is well main- 
 tained until the cut-off valve commences to close, 
 when the pressure falls in an increasing ratio, prob- 
 ably to about the pressure indicated by the dots at 
 the exact distance of closing. 
 
 In the preparation of this paper, and in the 
 selection of diagrams for its illustration, its object 
 has been carefully kept in view, and while it is 
 hoped that nothing has been omitted which is 
 essential to guide one before unacquainted with the 
 Indicator in learning how to employ it correctly 
 and intelligently, care has been taken to introduce 
 only those topics, and to consider these, only to 
 that extent which seemed to be necessary for this 
 purpose. 
 
 THE THEOEETIC CURVE AND ITS USES. 
 
 When we wish to know the condition of the 
 internal working of an engine from a diagram we 
 have taken from it, we make a perfect diagram 
 
 worn out; heating, straining, and thnmping, with all their 
 concomitant evils, are daily caused by excessive steam lead ; 
 while, by compressing, the piston meets the thin elastic vapor 
 remaining in the cylinder without a shock. It is technically 
 called " cushioning," a most appropriate term. 
 
68 BICHARDS STEAM-ENGINE INDICATOR. 
 
 around it so we may compare the one with the 
 other. 
 
 To do this : First, we ascertain the clearance 
 between the piston and cover, also the areas of the 
 ports and passage-ways clear back to the valves, 
 both steam and exhaust, if they be separate. 
 
 This we reduce to cubic inches ; we then get the 
 cubic inches of the cylinder, or that part of it occu- 
 pied by the stroke. Suppose the cylinder to be 14" 
 diameter, and 36" stroke, it will contain 5541.48 
 cubic inches. Now, then, suppose our clearance is 
 206.44 cubic inches ; this being divided into the 
 contents of the stroke part of the cylinder, 5541.48, 
 gives us 27, or is ^ part of it. We then add to the 
 steam end of our diagram ^ part of its length. 
 We then draw the line of perfect vacuum, whether 
 it is a condensing engine or not. Then we space 
 the whole in ten or more equal divisions, and erect 
 lines (ordinates) on these spaces at right angles to 
 our vacuum line, as shown in diagram No. 0. 
 
 We will suppose we have 100 Ibs. from A to B, 
 Diagram No. 0, measuring from the line A E, and 
 we cut off at 0, which is ^ or ^; by the law of expan- 
 sion we should find (having expanded the steam ) 
 the terminal pressure to be -J- of the pressure at C, 
 the steam having expanded, $ of the whole diagram. 
 To find the point where the true curve should bisect 
 the ordinates, we have numbered them from one to 
 ten. We find the steam is cut off at 2, the next 
 ordinate is 3, this being | the length of 2 ; hence, 
 
KICHAKDS' STEAM-ENGINE INDICATOR. 69 
 
 we use 2 for the numerator and 3 for the denom- 
 inator, and so on to the end, using for the numera- 
 tor the number of the ordinate where the steam is 
 cut off, and for a denominator the number of the 
 ordinate whose length we seek. 
 
 It often happens in spacing our diagrams that 
 we can't find a space that will come right in both 
 divisions of the diagram. In that case we space 
 the parts from B to C into equal spaces, say from 
 J" to |" each and then space the remainder the same; 
 if it should run over the termination of the diagram 
 it is of no importance, as after the curve is estab- 
 lished the measure will be taken at the terminal 
 point. The practical application of the theoretic 
 curve is this : If we find it below the curve given 
 by the instrument, we seek for the cause ; if the 
 engine cuts off short, say at J or less of the stroke, 
 we may expect to find it a little, say a pound or 
 two, above, at the last \ or f of the stroke; this is 
 accounted for by re-evaporation of the water con- 
 densed in the first part of the stroke. But, if it 
 should run as it often does 10 or 15 pounds above, 
 we conclude at once that the steam valve leaks. 
 If we find the curve made by the instrument fall- 
 ing below the theoretic line, we are certain that 
 either the piston or exhaust valve leaks, or may be 
 both. 
 
 Diagram No. 15 was taken from an engine 
 24" X 48", making 50 revolutions per minute. The 
 steam valves are of the class known as balanced 
 
70 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 poppet ; the exhaust valves plain slide ; point, of 
 cut-off adjusted by the action of the governor. 
 Boiler pressure 48 Ibs., steam pipe 6" diameter by 
 150' in length, the exhaust pipe 1" diameter by 175' 
 long, scale of the instrument 30 Ibs. to the inch; 
 work being done, driving two trains of rolls, one 
 of 20", the other of 16" diameter, with the concom- 
 itant and other machinery. 
 
 It will be observed that the pressure in the cylin- 
 der fell off some . 10 Ibs. from the initial in the 
 boiler, which is easily accounted for by the great 
 length of the steam pipe. The 2 Ibs. back pressure 
 may be accounted for by the excessive length of the 
 exhaust pipe ; these defects are no fault of the 
 engine. 
 
 The card is a very excellent one; we rarely see its 
 equal no superiors, unless from an engine whose 
 cylinder is jacketed with high steam. It will be 
 seen that the lines given by the instrument vary 
 but little from theoretic curve. The engine was 
 constructed by Messrs. Woodruff & Beach, under 
 Mr. Wm. Wright's patent. 
 
 Diagram No. 16 was taken from the top of the 
 cylinder of the steamer Newport; it will be recog- 
 nized by the engineer as very good. The steam 
 pressure on the boiler was by the gauge 22 Ibs., 
 vacuum per gauge 26". It will be seen that the 
 diagram shows 20.5 Ibs. The terminal point is sup- 
 posed to be as should be; yet, not having the data 
 to calculate the area of the clearance, passage-ways, 
 
RICHARDS' STEAM-ENGINE INDICATOR. 7^ 
 
 etc., we cannot ascertain where the terminal point 
 should be, exactly. 
 
 If the exhaust had opened a little earlier, it 
 would have improved the vacuum at its commence- 
 ment. 
 
 Diagram No. 17 is from an engine 24" diameter 
 X48" stroke, 60 revolutions per minute, Babcock 
 & Wilcox patent ; cylinder jacketed with steam 
 from the boiler. The clearance is ^ of the stroke, 
 boiler pressure 72 Ibs. to square inch, scale 40"=1". 
 
 This engine is in the flouring mills of Messrs. 
 Chapin, Miles & Co., Milwaukie. 
 
 The work being done when the diagrams were 
 taken was driving 4 runs of 4' 6" stones, and 2 runs 
 of 4' ; 180 revolutions per minute, with all the 
 required flouring machinery as used in such mills. 
 
 We give this data, that any one who wishes can 
 make the theoretical curve; it will be found almost 
 perfect. 
 
 The expansion line, it will be noticed, is some- 
 what waved, which is incident to the high speed, 
 high pressure, and early opening of the valves. 
 
 The terminal point of the expansion line will 
 be found about 3 Ibs. above the true line, caused 
 by evaporation of water that went over with the 
 steam. 
 
 Another and unusual point is the very near 
 approach of the pressure in the cylinder to that in 
 the boiler, being but 2J Ibs. less. When we take 
 into consideration the speed of the piston, 480' per 
 
72 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 minute, the result is extraordinary and seldom 
 attained. 
 
 Diagram No. 18 ; these cards were taken from 
 a Wilcox air engine, and beautifully illustrate the 
 delicate action of the Richards Indicator. Fig. 1 
 is from the working cylinder ; the receiving line 
 shows the induction valve to be slightly behind 
 time; the pressure gradually reduces the first of the 
 stroke, as the reservoir containing the compressed 
 air is small, but as soon as the pump begins to 
 deliver into the reservoir, the pressure continues 
 uniform till the induction valve closes near the end 
 of the stroke; the exhaust is free, and there is a 
 slight compression at the end of the return stroke. 
 
 Fig. 2 is from the pump, whicb is of the capa- 
 city of the working cylinder, and shows the gradual 
 increase of pressure as the piston descends and 
 compresses the air; the curves or waves at the 
 point of greater pressure show the power required 
 to open the eduction valve; the pressure then con- 
 tinues uniform till the induction to the working 
 cylinder closes, when the pressure runs up ; at the 
 commencement of the return stroke of the pump 
 piston, the pencil mark inclines back, showing the 
 time required for the closing of the eduction valve, 
 and the wave below the atmospheric shows the 
 time and power for opening the induction valve. 
 
 The working cylinder is 16" X 16" stroke, and 
 makes 70 revolutions per minute, scale 12 Ibs. to 
 one inch. 
 
RICHARDS' STEAM-ENGINE INDICATOR. 73 
 
 The pump, Fig. 2, is the capacity of the work- 
 ing cylinder, Fig. 1; hence, we measure the average 
 pressure of the two diagrams, each separately. 
 Suppose the working cylinder to show an average 
 of 10 Ibs. to the square inch, and the pump diagram 
 to show 9 Ibs. to the square inch. The pump being 
 f of the capacity of the working cylinder, we divide 
 the mean pressure, which we have assumed as 9 Ibs., 
 by 3, the quotient is 3, this added to 10 is 13; 3 sub- 
 tracted from 9 leaves 6, which subtracted from 13 
 leaves 7 Ibs. effective pressure per square inch on 
 the piston. 
 
 Our author concludes the work with a graphic 
 account of " A Bide on the Buffer Beam" on the 
 Great Eastern Railway, making the trip from Lon- 
 don to Yarmouth (England) in company with Mr. 
 Zerah Colburn, for the purpose of taking diagrams 
 from the engines, in which they were eminently 
 successful; which the compiler of this, owing to the 
 prescribed limits of this work, reluctantly feels 
 compelled to omit, and substitute an account of a 
 similar, though shorter, trip from Wilmington, 
 Del., to Philadelphia, on the Philadelphia, "Wil- 
 mington and Baltimore E. E. Through the kind- 
 ness of Mr. G. W. Perry, master of machinery of 
 that road, Locomotive No. 50, a first-class express 
 engine built by " the Taunton Locomotive W T orks" 
 cylinders 16" diameter by 24" stroke, four driving 
 wheels 5' 6" diameter, making 305.46 revolutions to 
 fche mile was placed at the disposal of the writer, 
 
74 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 and fitted for the occasion under his directions by 
 Mr. S. A. Hodgman, the able and efficient master 
 mechanic of the shops. The engine is outside con- 
 nected. The diagrams were taken from the for- 
 ward end of each cylinder. Short J ' ' pipes were 
 screwed into the top parts of the cylinder covers, 
 with elbows f " internal diameter pointing upwards, 
 to which the Indicators were attached. An iron 
 rail was secured to the signal flag-stands on the 
 narrow platform in front; a packing-box some 9" 
 high served as a seat for each operator, with his 
 back to the wind, and the Indicator between his 
 knees. 
 
 The method employed for giving motion to the 
 papers was very simple. A plank on each side of 
 the boiler, running from the cab to the platform, 
 about 3 ' above the cross-head, and directly over it, 
 which was used for the purpose of going forward 
 to oil, etc., was morticed through in the proper 
 place, and a bracket with a hole through it to 
 secure the arm to, was bolted to the plank beside 
 the mortice. A stud with a nut on it was fastened 
 to the bracket, pointing outwards horizontally. A 
 light arm swung from this stud and received a 
 vibratory motion from another stud screwed into 
 the side of the cross-head, working in a well-fitted 
 slot in the lower end of the arm. A button-headed 
 pin was inserted in this arm at about 7" below the 
 point of suspension, and to this was attached the 
 cord leading directly to the Indicator, giving to the 
 3 
 
RICHARDS' STEAM-ENGINE INDCCATOR. 75 
 
 paper a motion of 4J". Great care was taken to 
 set the arm, so that when the engine was on the 
 half-stroke and the cord attached to the instru- 
 ment, it might be at right angles with the arm. 
 The cord had a hook about 2" long, with a bend 
 about 1J" diameter, with a corresponding one on 
 the instrument cord, which made it easy to attach 
 under any speed. The hook on the cord was 
 secured by two other cords to keep it in position, 
 allowing it to move back and forth, but not to fall 
 when disengaged, where it could not be readily 
 seized. 
 
 It was arranged with the engineer that he should 
 run at all times with the throttle-valve fully open, 
 governing the speed entirely by changing the point 
 of cut-off. Everything being ready, Mr. Hodgman, 
 the master mechanic of the shops, and myself, pre- 
 pared to mount the platform. It being the month 
 of November, and not being very warm, an extra 
 overcoat was put on; a pair of woollen gloves, 
 fingers amputated at the second joint, leaving 
 enough of the finger bare to manipulate the instru- 
 ments, were found to work well. 
 
 Our first essay was with the engine and tender 
 alone, to see that all was right. We took several 
 diagrams, both on the forward and backward mo- 
 tions. We found the valves remarkably well set. 
 
 Diagram No. 19 is one of a pair that were taken 
 when running about 20 miles per hour; working 
 the steam full stroke, both backwards and forwards, 
 
76 BICHAKDS* STEAM-ENGINE INDICATOR. 
 
 shows how nearly the two actions correspond. Its 
 mate from the right-hand cylinder is a perfect fac- 
 simile of the one we engrave. In taking these cards, 
 the throttle was quite open. Pressure of steam not 
 noted. The scale of the instrument 40 to the inch. 
 During these preliminary experiments, an unfortu- 
 nate accident happened to one of the instruments 
 by breaking a spring. Not having an extra 40 
 spring, we substituted a 30 spring in each instru- 
 ment, and that we might get sufficient range, we 
 put washers between the end of the spring and the 
 piston, of sufficient thickness to carry the piston 
 down to the vacuum line, thereby giving us a scope 
 of 15 Ibs. more, and sufficient to answer the require- 
 ments for 105 Ibs. pressure in the cylinders. I men- 
 tion this for the reason that should the young 
 engineer meet with a similar mishap, he may be 
 posted on the subject. The delay caused by this 
 mishap prevented us from carrying out a programme 
 we had made previously. At 4 p. M. the express 
 train arrived from Baltimore, which it had been 
 arranged for us to take to Philadelphia. We took 
 diagrams at speeds varying from 30 to 60 or more 
 miles per hour, with great facility, at full stroke, and 
 cutting off at various points. In consequence of 
 our weak springs, our experiments were limited in 
 pressure to 105 Ibs., hence we could not maintain 
 our speed when cutting off short. 
 
 Diagram No. 20, scale 30 to the inch from the 
 right hand cylinder, cutting off at about one fourth 
 
EICHAEDS 
 
 ^-' 1 - :R " 
 
 STEAM-ENGINE INDICATOK. 
 
 stroke, was taken at 60 miles per hour, piston making 
 1,222 feet per minute, 305.46 revolutions. Notwith- 
 standing this extraordinary speed of piston, the 
 lines are all well denned, showing distinctly the 
 points of cut-off and release. A remarkable point 
 in the diagram is, that though the pencil passed 
 over it certainly twice or more, the lines are 
 very near to each other, showing that even under 
 this unprecedented speed of piston the instrument 
 was uniform and reliable in its action. This is not 
 a selected diagram ; all others taken on the trip 
 show the same characteristics, 
 
 Diagram No. 21, same scale, from the left-hand 
 cylinder, cutting off one notch shorter, with a higher 
 pressure of steam, taken next after the foregoing, 
 exhibits the same general features, though taken 
 under a higher speed. 
 
 Diagram No. 22, same scale, was next taken, 
 working full stroke, with, as will be seen, throttle 
 full open ; the speed increasing to such a degree 
 that the engineer thought it prudent to put on 
 cut-off. 
 
 This, as do all the other diagrams taken from the 
 engine, shows most marked points in the construc- 
 tion and setting of the valves; notwithstanding the 
 great speed, the steam line is held uniform to the 
 points of release. The exhaust line is all that can 
 be desired. The back pressure is merely nominal, 
 the exhaust nozzles being 4 J" each. In getting the 
 diagrams, the writer was ably seconded by Mr. 
 
78 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 Hodgman, who, though it was his first attempt at 
 taking diagrams, was remarkably efficient and cor- 
 rect. 
 
 We have spoken of the accuracy of the valve- 
 setting. These valves were set wholly by marks 
 on the wheels, slides, and valve-rods, with steam 
 on, and of course valve-chest covered, which is the 
 only method by which they can be correctly set, 
 owing to the expansion of the parts by heat. 
 
 We would here refer the engineer who wishes to 
 be well informed on the important art of valve- 
 setting, to a very excellent work on the slide valve 
 and link motion by Mr. W. S. Auchincloss, recently 
 published by D. Van Nostrand, 23 Murray-street, 
 New York, which is the result of great research and 
 practical experience; from which we copy: 
 
 "HOW TO SET A SLIDE VALVE HAVING EQUALIZED 
 EXHAUST. 
 
 " 1. Place the crank at the 180 location, mark 
 on the cross-head and one of its guides opposing 
 ' centre punch ' points, 
 
 " 2. Bring the crank to the zero and mark a se- 
 cond point on the guide. The two points thus 
 found, measure the length of the stroke. Move the 
 eccentric until the valve has the required lead for 
 the forward stroke. 
 
 " 3. Advance the crank in the direction of the 
 motion until the exhaust of the opposite stroke 
 
RICHARDS' STEAM-ENGINE INDICATOR. 79 
 
 closes ; scribe a line across the guide which shall 
 pass through the point on the cross-head. 
 
 " 4. Move the crank until the other exhaust closes 
 and scribe a second line on the guide. 
 
 " 5. If now the exhaust should close at equal dis- 
 tances from the commencement of each stroke, the 
 motion would be in adjustment; if not, alter the 
 length of the eccentric rod until the closure becomes 
 equalized, then return the crank to the zero posi- 
 tion, and alter the angular advance of the eccentric 
 until the required lead of the forward stroke is 
 secured. 
 
 " The position of the valve at the moment of 
 closure may readily be fixed by means of a ' valve 
 gauge ' fitting centre punch points on the valve 
 stem and its stuffing box. 
 
 " The above process will serve also to equalize 
 the cut-off if the valve be proportioned for this 
 object." 
 
 The trip was not without its discomforts, however 
 successful it might have been, being accomplished 
 on a November afternoon, with rather a low ther- 
 mometer ; with nothing at our backs to break off 
 the wind, with low seats and otherwise constrained 
 positions, we at the conclusion of our trip found 
 ourselves somewhat cold and a little stiff. Had it 
 been a summer day, this source of discomfort would 
 not have been, and we should have enjoyed the 
 excitement of our trip much. 
 
 So far as it is known to the writer, the above is 
 
80 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 the first successful application of the Indicator to 
 a locomotive, when making a regular trip on the 
 road, in this country. It is quite certain that there 
 is no Indicator known but the Richards, that can 
 be successfully used for the purpose. We will con- 
 clude with Mr. Porter's concluding paragraphs of 
 his " Bide on a Buffer-Beam :" 
 
 " These diagrams are taken under fewer difficul- 
 ties than would be at first imagined, if the weather 
 is pleasant, and the proper provision is made for 
 the comfort and security of the operators. The 
 principal difficulty is from the wind, which, at very 
 high speed, approaches more nearly to a hurricane 
 than anything that one is able to experience in this 
 latitude in any other way, and the labor of resist- 
 ing it becomes quite wearisome, if the operator is 
 not somewhat protected from its force. No un- 
 pleasant sensation whatever is produced by the 
 rapid motion, the passing of trains is scarcely ob- 
 served, and if no accident happens, there is no 
 danger more than in the carriages. Good weather 
 is essential to the satisfactory accomplishment of 
 the objects of such an excursion." 
 
RICHARDS' STEAM-ENGINE INDICATOR. 
 
 81 
 
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RICHARDS' STEAM-ENGINE INDICATOR. 
 
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RICHARDS' STEAM-ENGINE INDICATOR. 
 
 83 
 
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 xo 10 W>v5 
 
 OO rJ-vO COVO to O O VO OO toOO 
 
 00 ""> CO co rj- r> N OO to 4 vot^M 
 H-iOO vo - - 
 
 CO 
 
 "1VO 
 
 OO ONt^ OOO 
 OO M 
 
 < 
 
 wi-ioONrO'-'vO C\OO tr> 
 M to COOO OO rf to N w> Tj- 
 
 NOOvOvOt^ OO t>vO t^ ON roOO 
 r^fOOt^r}- MONt^T^-M OOOr-^io 
 CO TJ- u-> u->\O t~^ t^OO ON O -" M M rn 
 
 N-ii^ONO t>-i-'MOvOOOOO tooO ON 
 t^OOOMfOOOOt^OOO C^NOO ONVO 
 
 - 
 
 * *-i OO vO rj- >- ONOO 
 i\o t^ t^OO ON O O "- 
 
 '-' vr>i/->ON 
 
 _ _ ...O "-" covO <H t-^ 
 
 vo C4 ONVO CO Ot^LOcO"-" ONr^-vorJ-M 
 
 CO ^ Tj- uo\O t^. t^OO ON O O <- N CO <* 
 
 HHWWWM M IH l-l l-l M NNMWM 
 
 vo *s" 
 
 -I O ON( 
 
 vovO vO 
 
 W N N M 
 
 o OO vO >-o tr> 
 xOi-iOOiON 
 r-> Tf rt xovO 
 
 ^-oo N O 
 vO^l-rO'-' 
 -'Mro i <4 
 
 r-^vo t^ o '4' 
 O ONOO OO t~^ 
 Ln iOvO t^OO 
 
 ^vO ^" O co co O ^J" to ^" ON ^< *^ OO M 
 
 1-1 ON co cooo ONVO OO <O O ON vovO IN vo 
 
 vo oVoo 06 6 4- o\vd to -4-vo oV 4- 6 
 
 *J- M t^ -<^- >-, ONVO CO -< ON t>.vocOvN w 
 
 co ^" Tt* vovO vo t^CO ON ON O *"* N co ^" 
 
 OO t^OO -" 
 ONOO r^ r-v 
 Tj- vovO r^ 
 
 wi-i rot^WOOr^ 
 ^ "-* OOJ->roOOO vO-^- 
 t^.OO ON ON O -* 
 
 OO>-<tni-i 
 
 COOO u">Tj-rfvOCNTj-i-iONOOOMf^rO 
 
 >Tj-rf 
 coO 
 
 LOVO 
 
 O vr>\o 10 >-i CO CO O 
 t^OON-^-io >-ifO'-' 
 
 N'-'OO 
 
 ONMt^CO 
 VO ^'-" ON 
 vO t^OO OO 
 
 t^ co "- O "" Tt-OO rt- 
 - t^ voco ONOO 
 ON O " <M C co 
 
 "^ -<t- O co co O Tf-vO -^O "-"NOO 
 NTJ-C^LOT}- ONONiOt^^OOOt>>-i 
 
 O '- 
 
 ONVO 
 
RICHARDS STEAM-ENGINE INDICATOR. 
 
 U.UIBIQ 
 
 OO O 10 IH OO r^OO 
 
 ONVD ON t^ 1-1 
 
 IH .00 1000 viT O O 
 
 * oVvd 10 
 
 ONO IH 
 
 O 
 
 ON 
 
 VO N * 
 ^- cT 
 
 ONNVO N 
 CS VO t^ O 
 t^.00 ON HH 
 '^-TJ-TJ-IO 
 
 vovo 
 N^r> 
 
 MONCO COOO ON 
 
 Rt^VO t^ ON 
 vo vo vo vo 
 ON O i-< N co 
 N COCOCOCO 
 
 coOO co co voOO N ONVO 
 
 i>- t^oo ON o w N -^t- Brtsi 
 
 ^J" tovo r^o\ OI^MCOT!- 
 
 COCOCOCOCO ^Tj-Tj-Tj-^- 
 
 VO t 
 
 o\ IH 
 to r^oo 
 
 U 4 UIBIQ 
 
 vovo COOO ONOO 
 w ON CO N t^OO 
 
 O 
 
 CM cococo 
 
 Nt^^J-NN COVO M 
 
 VO vo t^OO ON O IH 
 
 TJ-IOVO i>-00 IH 
 
 cococococo 
 
 OO^OIHCIIH t^OOt^.iH COIHVO ONOO 10 ON O 
 CM COO M CO COOO 00 10 l>.ioOO r<N COONN 
 
 LO "* ^ ^ ^t- 10 u-jvo r^OO 
 ON O I-" M CO -^ iO\O t^OO 
 r cocococo cococococo 
 
 IOONIOCO NM 100 *d- 
 
 O >-> co 10 l>. ON IH covo 
 ro Tf iovO OO ON O 
 Ti-io 
 
 vO OO t^ co^O vO TJ-OO ONOO covO vOCMvO r^ioOcoCM 
 voioO IH r^ ON r>- O ON^- LO >-< coin ^- cooO ON 10 1-^ 
 
 IH 00 t^> t^OO IH VO CO O O IH 
 ^- rf IOVO t^ 00 
 
 T*- iovO r^oo ON 
 
 rj- t^.vO O IH 
 
 CM OO t^ t^OO iHVOCMOON OCMVOCMONOOOOO'^-ON 
 
 COCMCMCMCM COCOTj-iOio K.OO ON " ^ ^-vO ON CO 
 
 O\ O IH CM CO rj- iovO t^OO ON O IH CO ^ iovO > ON O 
 
 WCOCOCOCO COCOCO OCO CO ^1- ^ ^ ^ rj- rj- r^- -5J- 10 
 
 t^OO VO 
 rj-VO COVO ""> 
 
 H CM co * 10 
 
 VO t^OO ONO iHCM 
 vOOvovot>i t^t^ 
 
RICHARDS STEAM-ENGINE INDICATOR. 
 
 85 
 
 j^ureja 
 
 OOOOOOOQOQ OQOQOOOOON ON ON ON ON ON ON ON ON ON. O 
 
 vo ON ON t^ H< mc40Oi-ii-OOttmoir^ON ONVO ON O 
 i-iioxoi-imOmi-'vOvO 1-1 m O COM xovoi-i 0* O 
 
 r ON moo vo m m ^I^NOOV 
 
 ON N VO ON COVO O rJ-OO m t^ N t^ N t^ N OO m 
 ' 
 
 i-^oo >-< vo 1-1 oo 
 
 ON r^ N rj- m ON N N ON Tfr- vo m ON N -" 00 
 
 mmiOOOmOOO 
 
 ON N vo N 
 im-ivOW 
 
 ro iov0 00 
 
 10 t>.vO COVO VO COOO 
 
 ONOO TfvO 
 COO fO^ 
 
 N 1-1 N Tj-OO mOONON'-" 
 
 rj- t^ O fOvO Orl-t^.i-ivO 
 
 CJ CO LOVO t^ ON O CO ^ 
 
 lO 10 10 10 10 i-O\O vOVO^O 
 
 i-(T}-Tl-i-i 
 
 fOOO ONVO 
 
 ONVO CO vO O 
 
 ONOO ON i- ^ O VO ^O -OO ON 
 N u-)00 NvnONClVOOTt-OO 
 W co ^vO t^ OO O M co -^ v~) 
 
 ^OOOOO ONMir^i-i 
 
 C t^ M OO m ON 
 
 O >-< co ^f vO t^ 
 
 t^.t^ r^r^t^t^. 
 
 10 o 10 10 10 
 
 rom covo O 
 '-'O i-ivoc^ 
 
 O -i CO -^-VO 
 
 ON 
 
 M f>. ONOO ^J- r-OO 10 ON - 
 OvOCOvO 
 
 >O 10 >O vovO vo 
 
 OOO OO 
 
 NVO O ON 
 
 MXO>-IOOOO odo-^ovo 
 
 VOQiOONTh CMOOvO'-' 
 10 t^OO ON W ^l-vo t^. ON 
 
 lO rj- O CO Tf 1-1 vo 
 M t^OO 'sJ-vO 
 
 vO M tou-5MvOt^.ioOfONON 
 I-H OJ OO O OO 1-1 O *OVO N ^ H< 
 
 >-< Tf 00 N VO 
 >t^OO ONt-i M 
 
 10 10 iovo vo 
 
 rh ON COOO CO OO COOO Tj- O 
 1OVO OOON"-" NTj-iOt^ON 
 
 vovovOvo r>- t^t^t^t^.t>. 
 
 o6vdv6o6i-H 
 
 t^- O COVO O 
 
 to to *-i co -< ^- cooo oo -r 
 civdrl o\oo oo O rooo to 
 
 COt^r4vO'-'VONt^MOO 
 voO OO ON >-i N 'T 
 
 t*+ ONVO ONOO COCOONMOO 
 
 vomm^J'f s N oo to to vo 
 
 VO ON M voOO N vo ON co t^ 
 -i N -rf- vovO OO ON O M m 
 O to to to vo vo vovO VO VO 
 
 oo M r^ rj- co co vooo m ON 
 
 HH vO O to O vo O vo H vO 
 
 VOVO OO ON I-H C^ rj- vo f>00 
 
 vo vo vo vo t^ t^ t^^ c**- r^ t^^ 
 
 8N 
 O 
 
 CO'-'O'-''!}'OOTt-Mi-ii-< 
 tOOO i-i rj- t- O TfOO N VO 
 N Tf" vr.vo OO ON O N CO 
 vo to vo vo to vo vovo vovo 
 
 COI^-M ONOO OO ON C^ t^. ^ 
 
 O Tf- CN COOO COOO T*- ON vo 
 
 VOVQ t^ ON O M CO vovo OO 
 
 vovovot^r^. t^.r^t^.t>-t> 
 
 J,UIIQ 
 
 
 
 OOOOOOOOOO COOOOO 
 
86 
 
 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 Circumferences of Circles, advancing by lOths. 
 
 1 
 
 CIRCUMFERENCES. 
 
 1 
 
 o 
 
 ., 
 
 .2 
 
 3 
 
 4 
 
 S 
 
 6 
 
 -7 
 
 .8 
 
 9 
 
 5 
 
 
 
 
 
 
 
 
 
 
 
 O 
 
 .00 
 
 .31 
 
 .62 
 
 94 
 
 I 25 
 
 1-57 
 
 1.88 2.19 
 
 2.51 
 
 2.82 
 
 I 
 
 3.14 
 
 3-45 
 
 3.76 
 
 4.08 
 
 4.39 
 
 4.71 
 
 5-02 5.34 
 
 5.65 
 
 5 96 
 
 2 6.28 
 
 6 59 
 
 6.91 7.22 
 
 7-53 
 
 7 85 
 
 8.16 8.48 
 
 8.79 
 
 9.11 
 
 3 9.42 
 
 9.73 10.05 10.3610.68 
 
 10.9 
 
 11.30 
 
 11.62 
 
 ii 93 
 
 12.25 
 
 412.56 
 
 12.88^3. 19 13.50 13.82 
 
 14-13 
 
 H 45 
 
 14.76 15.07 
 
 15 39 
 
 5 I 5-7 O 
 
 16.02 16.33 
 
 16.65 16.96 
 
 17.27 
 
 17-59 
 
 17.90 l8.22 
 
 18.53 
 
 618.84 
 
 19.1619 47 
 
 19.7920. 10 
 
 20.42 
 
 20.73 
 
 21.04 
 
 21.36 
 
 21.67 
 
 721.99 
 
 22.3022.61 
 
 22.9323.24 
 
 23.5623^,87 
 
 24.1924.5024 Si 
 
 825.13 
 
 25 4425.7626.07 
 
 26.3826.7027.01 
 
 27-3327 6427.96 
 
 928.27 
 
 28.5828.9029.21 
 
 29-53 
 
 29.8430.15 
 
 30.4730.7831.10 
 
 1031.41 
 
 31.7332-0432.35 
 
 32.67 
 
 32.9833 3033-61 
 
 33-92 
 
 34.24 
 
 "34-55 
 
 34.8735.18 
 
 35.50 
 
 35-81 
 
 36.1236.44 
 
 36.75 
 
 37-07 
 
 37.38 
 
 1237.69 
 
 38.0138.32 
 
 38.64 
 
 38.95 
 
 39.27 
 
 39.5839-8940.2i 
 
 40.52 
 
 1340.84 
 
 41.1541.46 
 
 41.78 
 
 42.09 
 
 42.41 
 
 42.72 
 
 43-0343-35 
 
 43-66 
 
 I443-98 
 1547.12 
 
 44.2944.61 
 47-4347-75 
 
 44.9245.23 
 48.0648.38 
 
 45.5545.86 
 48.6949.00 
 
 46.1846.49 
 49.3249.63 
 
 46.80 
 49 95 
 
 1650.26 
 
 50. 57' 50. 89 
 
 51.20 
 
 5I-52 
 
 5i 83 
 
 52.15 
 
 52.4652.77 
 
 53-09 
 
 1753 40 
 
 53.7254.03 
 
 54-34 
 
 54-6054.97 
 
 55-29 
 
 55.6055.92 
 
 56-23 
 
 1856.54 
 
 56.86,57/17 
 
 57-49 
 
 57.80 
 
 58.11 
 
 58.43 
 
 58.74 59.O6 
 
 59-37 
 
 1959.69 
 
 60.0060.31 
 
 60 63 
 
 60.94 
 
 61.2661.57 
 
 6l.8862.20 
 
 62.51 
 
 20 62 . 83 
 
 63.1463.46 
 
 63-77 
 
 64.08 
 
 64.4064.71 
 
 65.0365.34 
 
 65.65 
 
 2165.97 
 
 66.28 
 
 66.60 
 
 66.79 
 
 67.29 
 
 67.54 
 
 67-85 
 
 68.17 
 
 68.48 
 
 68.80 
 
 2269.11 
 
 69 42 
 
 69.74 
 
 70.05 
 
 70 37 
 
 70.68 
 
 71 oo 
 
 7L3I 
 
 71.62 
 
 71.9^ 
 
 23 
 
 72.25 
 
 72-57 
 
 72.88 
 
 73-19 
 
 73. 51 
 
 73.82 
 
 74 14 
 
 74-45 
 
 74.76 
 
 75 8 
 
 24 
 
 75 39 
 
 75-71 
 
 76.O2 
 
 76.34 
 
 76.65 
 
 76.96 
 
 77.28 
 
 77-59 
 
 77.91 
 
 78.22 
 
 25 
 
 78 54 
 
 78 85 
 
 79.16 
 
 79.48 
 
 79-79 
 
 80. ii 
 
 80.42 
 
 80.73 
 
 81.05 
 
 81.36 
 
 26 
 27 
 28 
 
 81.68 
 84.82 
 87.96 
 
 81.99 
 
 85-13 
 88.27 
 
 82.30 
 85.45 
 
 88.59 
 
 82.62 
 85.76 
 88.90 
 
 82.93 
 86.07 
 89.22 
 
 $5 
 
 89-53 
 
 83.56 
 86.70 
 89.84 
 
 83.88 
 87.02 
 90.16 
 
 84.19 
 87-33 
 90.47 
 
 84-50 
 87.65 
 90-79 
 
 29 
 
 91. 10 
 
 91.42 
 
 9i 73 
 
 92.04 
 
 92.36 
 
 92.67 
 
 92.99 
 
 93.30 
 
 936i 
 
 93-93 
 
 30 
 
 94.24 
 
 94-56 
 
 94.87 
 
 95.19 
 
 95-50 
 
 95 81 
 
 96-13 
 
 96.44 
 
 96.76 
 
 97.07 
 
 31 
 
 97.38 
 
 97.70 
 
 98.01 
 
 98.33 
 
 9864 
 
 98.9699.27 
 
 99-58 
 
 99.90 
 
 100.2 
 
 32 
 
 100.5 
 
 100.8 
 
 IOI.I 
 
 101.4 
 
 101.7 
 
 102. I 102.4 
 
 102.7 
 
 103 o 
 
 i3 ; 
 
 33 
 34 
 
 103.6 
 106.8 
 
 103.9 
 107.1 
 
 104.3 
 107.4 
 
 104.6 
 107.7 
 
 104.9 
 108.0 
 
 105.2 105 5 
 108.3 Io8 ( 
 
 105.8 
 
 109.0 
 
 106.1 
 109.3 
 
 109.6 
 
 35109-9 
 
 no. 2 
 
 110.5 
 
 no 8 
 
 III. 2 
 
 111.5 in. 8 
 
 112. I 
 
 112.4 
 
 II2-7 
 
RICHARDS STEAM-ENGINE INDICATOR. 
 
 Circumferences of Circles, advancing by lOths. 
 
 Diameter. | 
 
 CIRCUMFERENCES. 
 
 .0 
 
 .1 
 
 .2 
 
 .3 
 
 4 
 
 .5 
 
 .6 
 
 -7 
 
 .8 
 
 .9 
 
 36 
 
 113.0 
 
 II3-4 
 
 II3-7 
 
 114.0 
 
 114.3 II4.6 
 
 II4.9 
 
 II5.2 
 
 IIS-6 
 
 H5-9 
 
 37 
 
 116.2 
 
 116.5 
 
 II6.8 
 
 117.1 
 
 117.4 117.8 118. 1 
 
 II8.4 
 
 II8.7 
 
 119.0 
 
 38 
 
 119.3 
 
 II9.6 
 
 120.0 
 
 120.3 
 
 120.6 120.9 
 
 121. 2 
 
 I2I.5 
 
 121. 8 
 
 122.2 
 
 39 
 
 122.5 
 
 122.8 
 
 I23.I 
 
 123.4 
 
 123.7:124.0 
 
 124.4 
 
 124.7 
 
 125.0 
 
 125-3 
 
 40 
 
 125.6125.9 
 
 126.2 126.6 
 
 I26.9|I27.2 
 
 127.5 
 
 127.8 
 
 128.1 
 
 128.4 
 
 41 
 
 128.8129.1 
 
 129.4 I2 97 
 
 I30.0I30.3 
 
 130.6 I3I.O 
 
 131.3 
 
 I3I.6 
 
 42 
 
 131.9:132.2 
 
 132.5132.8 
 
 I33-2I33.5 
 
 I33-8I34.I 
 
 134.4 
 
 134.7 
 
 43 
 
 135.0135.4 
 
 135.7136.0 
 
 136.31136.6 
 
 I36.9I37.2 
 
 137.6 
 
 137.9 
 
 44 
 
 138.2138.5 
 
 138.8 139.1 
 
 139.4139.8 
 
 I40.I 140.4 
 
 140.7 
 
 I4I.O 
 
 45 
 
 141.3 141.6 
 
 142.0 
 
 142.3 
 
 142.6142.9^43.21143.5 
 
 143.8 
 
 I44.I 
 
 46 
 
 144-5144-8 
 
 I45- 1 
 
 145-4 
 
 145.7146.0146.3 146.7 
 
 147.0 
 
 147-3 
 
 47 
 
 147-6147-9 
 
 148.2 
 
 148.5 
 
 148.9 149.2 
 
 I49.5I49.8 
 
 150. 1 
 
 150.4 
 
 48 
 49 
 
 150.7,151.1 
 153-9154.2 
 
 I5I-4 
 154-5 
 
 151-7 
 154.8 
 
 I52.O 
 I55-I 
 
 152-3 
 155-5 
 
 I52.6I52.9 
 155.8 I56.I 
 
 15^.3 
 
 156.4 
 
 153-6 
 156.7 
 
 5 
 
 157.0157.3 
 
 157-7 
 
 158.0 
 
 158.3 
 
 158-6 
 
 158.9 
 
 159.2 
 
 159.5 
 
 159.9 
 
 51 
 
 160.2 
 
 160.5 
 
 160.8 
 
 161.1 
 
 161.4 
 
 161.7 
 
 I62.I 
 
 162.4 
 
 162.7 
 
 163.0 
 
 5 2 
 
 163.3163.6 
 
 163.9 
 
 164.3 
 
 164.6 164.9 165.2 
 
 165.5 
 
 165.8 
 
 I66.I 
 
 53 
 
 i66.5!i66.8 
 
 167.1 
 
 167.4 
 
 167.7 168.0 168.3 
 
 168.7 
 
 169.0 
 
 169.3 
 
 54 
 
 169.6 
 
 169.9 
 
 170.2 
 
 170.5 
 
 170.9171.2 
 
 I7L5 
 
 I7I.8 
 
 172.1 
 
 172.4 
 
 55 
 
 172.7 
 
 I73.I 
 
 173-4 
 
 173-7 
 
 174.0174.3 
 
 174.6 
 
 174.9 
 
 175.3 
 
 175.6 
 
 56 
 
 175-9 
 
 176.2 
 
 176-5 
 
 176.8 
 
 177.1 
 
 177-5 
 
 177.8 
 
 I78.I 
 
 178.4 
 
 178.7 
 
 57 
 
 179.0 
 
 179.3 
 
 179.6 
 
 180.0 
 
 180.3 
 
 180.6 
 
 180.9 
 
 181.2 
 
 181.5 
 
 181.8 
 
 58 
 
 182.2 
 
 182.5 
 
 182.8 
 
 183.1 
 
 183.4 
 
 183-7 
 
 184.0 
 
 184.4 
 
 184.7 
 
 185.0 
 
 59 
 
 185-3 
 
 185.6 
 
 185.9 
 
 186.2 
 
 186.6 
 
 186.9 
 
 187.2 
 
 187.5 
 
 187.8 
 
 188.1 
 
 60 
 
 188.4 
 
 188.8 
 
 189.1 
 
 189.4 
 
 189.7 
 
 190.0190.3 
 
 190.6 
 
 191.0 
 
 191-3 
 
 61 
 
 191.6 
 
 I9I.9 
 
 192.2 
 
 192.5192.8 
 
 193.2 
 
 193-5 
 
 193.8 
 
 194.1 
 
 194.4 
 
 62 
 
 194.7 
 
 I95.O 
 
 195-4 
 
 195.7196.0 
 
 196.3 
 
 196.6 
 
 196.9 
 
 197.2 
 
 197.6 
 
 63 
 
 197.9 
 
 198.2 
 
 198.5 
 
 198.8199.1 
 
 199.4 
 
 199.8 
 
 200.1 
 
 200.4 
 
 200.7 
 
 64 
 
 201.0 
 
 201.3 
 
 201.6 
 
 202.0 
 
 202.3 
 
 202.6 
 
 202.9 
 
 203.2203.5 
 
 203.8 
 
 65 
 
 204.2 
 
 204.5 
 
 204.8 
 
 205.1 
 
 205.4 
 
 205.7 
 
 206.O 
 
 206.4206.7 
 
 207.0 
 
 66 
 
 207-3 
 
 207.6 
 
 207.9 
 
 208.2 
 
 208.6 
 
 208.9 
 
 2O9.2 
 
 209-5J209.8 
 
 210. I 
 
 67 
 
 210-4 
 
 2I0.82II.I 
 
 211.4211.7 
 
 212.0 
 
 212.3 
 
 212.6213.0 
 
 213-3 
 
 68 
 
 213.6 
 
 2I3.92I4.2 
 
 214.5214.8 
 
 2I5.I 
 
 215-5 
 
 2i5.8'2i6.i 
 
 216-4 
 
 69 
 
 216.7 
 
 2I7.02I7.3 
 
 217.7218.0 
 
 218-3 
 
 218.6 
 
 218.9 219.2 
 
 219.5 
 
 70 
 
 219.9 
 
 22O.2|220.5 
 
 220.8'22I. I 
 
 221.4 
 
 221. 7 222. 1 '222. 4 
 
 222.7 
 
88 
 
 RICHARDS STEAM-ENGINE INDICATOR. 
 
 Circumferences of Circles, advancing by lOths. 
 
 Diameter. 
 
 CIRCUMFERENCES. 
 
 .0 
 
 .1 
 
 .2 
 
 3 
 
 4 
 
 5 
 
 .6 
 
 7 
 
 . .8 
 
 -9 
 
 71 
 
 223.0 
 
 223.3 
 
 223.6 
 
 223.9224.3 
 
 224.6224.9 
 
 225.2 
 
 225.5225 8 
 
 72 226. 1 
 
 226.5 
 
 226.8227.1227.4227.7228.0 
 
 228.3 
 
 228. 7^29. o 
 
 73229-3 
 
 229.6 
 
 229.9 230. 2 230. 5(230.9 231 . 2 
 
 231.5231.8232.1! 
 
 74232.4 
 
 232.7 
 
 233-1 
 
 233-4233-7 
 
 234.0234.3 
 
 234.6234.9235.3 
 
 75235 6235.9 
 
 236.2 
 
 236.5236.8 
 
 237-I237-5 
 
 237 8238.1238.4 
 
 76:238.7239-0 
 
 239-3239-7 
 
 24O.O 
 
 240.3240.6 
 
 240.9 
 
 241.2241.5 
 
 77241.9 
 
 242.2242.5242.8243.1 
 
 243 . 4 243 . 7 
 
 244.1 
 
 244.4244.7 
 
 78 
 
 245-0245.3245 6 1 245. 9 246 3 
 
 246.6246.9 
 
 247.2 
 
 247.5247.8 
 
 79 
 
 248.1 248.5248.8249. 1)249.4 
 
 249.7 
 
 250.0 
 
 250.3 
 
 250.6251.0 
 
 80 
 
 251.3251.6 
 
 25I-9252.2252.5 
 
 252.8 
 
 253.2 
 
 253-5 
 
 253.8254.1 
 
 81 
 
 254.4 
 
 254.7255.0255.4255.7 
 
 256.0236.3 
 
 256.6 
 
 256.9257.2 
 
 82 
 
 257.6257.9258.2258.5258.8 
 
 
 259.8 
 
 260.1 
 
 260.4 
 
 83 
 84 
 85 
 
 260.7 
 263.8 
 267.0 
 
 261.0261.3261.6262.0 
 264 . 2 264 . 5 264 . 8 265 . i 
 267 . 3 267 . 6 267 . 9*268 . 2 
 
 262.3262.6 
 265.4265 7 
 268.6268.9 
 
 262.9 
 266.0 
 269.2 
 
 263.2263.5 
 266.4266.7 
 
 269.5269.8 
 
 86 
 
 270.1 
 
 270.4270.8271.1271.4271.71272.0 
 
 272.3 
 
 272.6273.0 
 
 87 
 
 273-3 
 
 273-6273.9274.2274.5274.81275.2 
 
 275 5 
 
 275.8 
 
 276.1 
 
 88 
 
 276.4 
 
 276.7277.0 
 
 277.4277.7278 0278.3 
 
 278.6 
 
 278.9279.2 
 
 89 
 
 279.6 
 
 279.9280.2 
 
 280.5280.8281.! 
 
 281.4 
 
 281.8 
 
 282.1282.4 
 
 90 
 
 282.7 
 
 283.0283.3 
 
 283.6284.0284.3 
 
 284.6284.9 
 
 285.2285.5, 
 
 91 
 
 285.8 
 
 286.1286.5 
 
 286.8287.1287.4 
 
 287.7288.0 
 
 288.3 
 
 288.7 
 
 92 
 
 289.0 
 
 289.3289.6 
 
 289.9290.2290.5 
 
 29O-9 ! 29I.2 
 
 291.5 
 
 291.8 
 
 93 
 
 292.1 
 
 292 4292.7 
 
 293-1293.4293 7 
 
 294.0294.3 
 
 294.6 
 
 294.9 
 
 94 
 95 
 
 295-3 
 298.4 
 
 295 6295.9 
 298.7299.0 
 
 296.2 
 299-3 
 
 296.5296 8 
 299.7300.0 
 
 297.11297-5 
 
 300.31300.6 
 
 297.8 
 300.9 
 
 298.1 
 301.2 
 
 96 
 
 301.5 
 
 301.9302.2 
 
 302.5 
 
 302.8303.1 
 
 303.4 
 
 303-7 
 
 304-* 
 
 304-4 
 
 97 
 98 
 
 304 7 
 307.8 
 
 305-0305-3 
 308.1308.5 
 
 305 6 
 308.8 
 
 305.9306.3 
 309.1309.4 
 
 306.6 
 309 7 
 
 306.9 
 310.0 
 
 307.2 
 310.3 
 
 307-5 
 310.7 
 
 99 
 
 100 
 
 311.0 
 3H i 
 
 311 33" 6 
 314 4314.7 
 
 3" 9 
 
 315 -i 
 
 312.2312.5 
 3I5-43I5-7 
 
 312.9 
 316.0 
 
 313 2 
 316.3 
 
 313.5 
 
 316.6 
 
 313.8 
 316.9 
 
RICHARDS' STEAM-ENGINE INDICATOR. 
 
 89 
 
 If the areas of larger cylinders are required, they 
 will be found by the following RULE : Multiply the 
 square of the diameter by the decimal .7854, and 
 the product will be the area in square inches ; 
 or, multiply half the circumference by half the 
 diameter. 
 
 TABLE No. IL 
 
 Showing the weight of the atmosphere, in Ibs. avoirdupois, on 1 
 'square inch, corresponding with different heights of the barom- 
 eter, from 28 inches to 31 inches, varying by tenths of an 
 inch. 
 
 Barometer 
 in Inches. 
 
 Atmosphere 
 in Ibs. 
 
 Barometer 
 in Inches. 
 
 Atmosphere 
 in Ibs. 
 
 ! 
 ! Barometer 
 I in Inches. 
 
 Atmosphere 
 in Ibs. 
 
 28.0 
 
 13.72 
 
 29.1 
 
 14.26 
 
 i 
 30.1 
 
 14-75 
 
 28.1 
 
 13-77 
 
 29.2 
 
 H.3I 
 
 30.2 
 
 14.80 
 
 28.2 
 
 13.82 
 
 29-3 
 
 14.36 
 
 30.3 
 
 14 85 
 
 28.3 
 
 I3-87 
 
 29.4 
 
 14.41 
 
 30-4 
 
 14.90 
 
 28.4 
 
 13.92 
 
 29.5 
 
 14.46 
 
 30-5 
 
 14.95 
 
 28.5 
 
 13 97 
 
 29.6 
 
 14.51 
 
 30.6 
 
 15.00 
 
 28.6 
 
 14.02 
 
 29.7 
 
 14.56 
 
 30-7 
 
 I5-05 
 
 28.7 
 
 14.07 
 
 29.8 
 
 14.61 
 
 30.8 
 
 15.10 
 
 28.8 
 
 14 12 
 
 29.0 
 
 14.66 
 
 30-9 
 
 15-15 
 
 28.9 
 
 14.17 
 
 30.0 
 
 14.70 
 
 31.0 
 
 I5-I9 
 
 29.0 
 
 14.21 
 
 
 
 
 
RICHARDS' STEAM-ENGINE INDICATOR. 
 
 Elastic force in 
 
 
 
 Elastic force in 
 
 
 
 Inches 
 
 Pounds 
 
 Tempe- 
 rature. 
 
 Volume. 
 
 Inches 
 
 Pounds 
 
 Tempe- 
 rature. 
 
 Volume. 
 
 of 
 
 per 
 
 
 
 of 
 
 per 
 
 
 
 Merc'y. 
 
 Sq. In, 
 
 
 
 Merc'y . 
 
 Sq. in. 
 
 
 
 193.82 
 
 95- 
 
 328.2 
 
 310 
 
 306. 
 
 150. 
 
 363.4 
 
 205 
 
 203.99 
 214.19 
 
 100. 
 
 105. 
 
 332. 
 335-8 
 
 295 
 282 
 
 316.19 155- 
 326.39! 1 60. 
 
 366. 
 368.7 
 
 198 
 193 
 
 224.39 
 
 no. 
 
 339.2 
 
 271 
 
 336. 59 ( 165. 
 
 37I-I 
 
 187 
 
 234.59 
 
 ii5- 
 
 342.7 
 
 259 
 
 346.^9 170. 
 
 373-6 
 
 I8 2 
 
 244.79 
 
 120. 
 
 345-8 
 
 251 
 
 357- 175. 
 
 376. 
 
 178 
 
 254-99 
 
 125- 
 
 349-1 
 
 240 
 
 367.2 
 
 180. 
 
 378.4 
 
 174 
 
 265 19 
 
 130. 
 
 352-1 
 
 233 
 
 377-1 
 
 185. 
 
 380.6 
 
 169 
 
 275-39 
 
 135- 
 
 355- 
 
 224 
 
 387.6 
 
 190. 
 
 382.9 
 
 166 
 
 285.59 
 295-79 
 
 140. 
 
 145- 
 
 357-9 
 360.6 
 
 218 
 2IO 
 
 397-8 
 408. 
 
 195- 
 
 200. 
 
 384.7 
 387-3 
 
 161 
 158 
 
 TABLE No. IV. 
 
 No. 
 
 Logarithm. 
 
 No. 
 
 Logarithm. 
 
 No. 
 
 Logarithm. 
 
 1.25 
 
 .22314 
 
 5- 
 
 .60943 
 
 9-5 
 
 2.25129 
 
 i-5 
 
 .40546 
 
 5.25 
 
 . 65822 
 
 10. 
 
 2.30258 
 
 i 75 
 
 .55961 
 
 5-5 
 
 .70474 
 
 II. 
 
 2.39789 
 
 2. 
 2.25 
 
 .69314 
 .81093 
 
 I: 75 
 
 .74919 
 79175 
 
 12. 
 13- 
 
 2.48490 
 2.56494 
 
 2-5 
 
 2-75 
 
 .91629 
 .OIl6o 
 
 625 
 6.5 
 
 83258 
 .87180 
 
 14. 
 15. 
 
 2.63905 
 
 3- 
 
 .09861 
 
 6.75 
 
 .90954 
 
 16. 
 
 2.77258 
 
 3 25 
 
 .17865 
 
 
 94591 
 
 17- 
 
 2.83321 
 
 3-5 
 
 25276 
 
 7^25 
 
 .98100 
 
 18. 
 
 2.89037 
 
 3 75 
 
 .32175 
 
 7-5 
 
 2.01490 
 
 19. 
 
 2-94443 
 
 4- 
 
 .38629 
 
 7-75 
 
 2.04769 
 
 20. 
 
 2-99573 
 
 4-25 
 
 .44691 
 
 8. 
 
 2.07944 
 
 21. 
 
 3- 4452 
 
 4-5 
 
 4-75 
 
 .50507 
 55814 
 
 8.5 
 9- 
 
 2.14006 
 2.19722 
 
 22. 
 
 3.09104 
 

 
 RICHARDS STEAM-ENGINE INDICATOR. 
 
 TABLE No. V. 
 
 Table of Steam used Expansively. 
 
 
 Average Pressure of steam in Ibs, per. square inch for the 
 
 
 whole stroke. 
 
 Initial 
 
 
 Pressure, 
 Ibs. per 
 
 Portion of stroke at which steam is cut off. 
 
 square inch. 
 
 
 
 * 
 
 X 
 
 * 
 
 % 
 
 X 
 
 * 
 
 5 
 
 4.8 
 
 4.6 
 
 4.2 
 
 3-7 
 
 2-9 
 
 i.9 
 
 10 
 
 9.6 
 
 9.1 
 
 8.4 
 
 7-4 
 
 5-9 
 
 3-8 
 
 15 
 
 14.4 
 
 13-7 
 
 12.7 
 
 11. i 
 
 8.9 
 
 5-7 
 
 20 
 
 19.2 
 
 18.3 
 
 16.9 
 
 14.8 
 
 11.9 
 
 7-6 
 
 25 
 
 24.1 
 
 22.9 
 
 21. 1 
 
 18.5 
 
 14.9 
 
 95 
 
 
 28.9 
 
 27-5 
 
 25.4 
 
 22.2 
 
 17.9 
 
 ii 5 
 
 35 
 
 33-8 
 
 32.1 
 
 29.6 
 
 25.9 
 
 20.8 
 
 13 4 
 
 40 
 
 37-5 
 
 36.7 
 
 33-8 
 
 29.6 
 
 23.8 
 
 15.4 
 
 45 
 
 g 
 
 fti 
 
 57-8 
 
 4i-3 
 45-9 
 
 42-3 
 50-7 
 
 33-3 
 37-o 
 44-5 
 
 26.8 
 29.8 
 35-7 
 
 17.3 
 19.2 
 
 70 
 
 67.4 
 
 64.3 
 
 592 
 
 52-4 
 
 41 -7 
 
 26.9 
 
 80 
 90 
 
 86*. 7 
 
 IU 
 
 67.7 
 76.1 
 
 si 
 
 47-7 
 53 6 
 
 30-8 
 34 6 
 
 100 
 
 96*3 
 
 91.8 
 
 84.6 
 
 74-i 
 
 59.6 
 
 38.4 
 
 no 
 
 106.0 
 
 IOI.O 
 
 93i 
 
 81.5 
 
 65.6 
 
 42.5 
 
 120 
 
 115.2 
 
 no. 2 
 
 101.5 
 
 89.4 
 
 7i-5 
 
 46.1 
 
 130 
 140 
 
 125.4 
 134.9 
 
 119.1 
 128.6 
 
 IIO.O 
 
 118.5 
 
 95-3 
 103.8 
 
 77-5 
 83-3 
 
 50.0 
 53-8 
 
 % 
 
 144.7 
 153-6 
 
 137-8 
 147.0 
 
 126.4 
 135.4 
 
 III 2 
 
 118.2 
 
 89-4 
 95-4 
 
 57-7 
 61.5 
 
 1 80 
 200 
 
 173-5 
 192.7 
 
 164.6 
 183-7 
 
 152-3 
 169.3 
 
 132.9 
 148.3 
 
 107.3 
 
 76*9 
 
54 KICHARDS STEAM-ENGINE INDICATOR. 
 
 We insert the Table No. Y, not for general use in 
 determining the mean pressure, as we have seen in 
 the example on page 62, that another element, the 
 clearance, has to be taken into account to get a cor- 
 rect result. Now, it is seldom we can get at the 
 drawings or patterns to get the measurement of the 
 clearance, hence we must seek some other mode. 
 
 We can easily find if the engine is tight or not, by 
 taking off the cylinder cover, putting the engine on 
 the half stroke, blocking the fly-wheel, and letting 
 team on the opposite side of the piston. Suppose 
 we find it tight in valves and piston, we then replace 
 the cover and take some diagrams, and find the 
 mean by measurement, as directed on page 62. We 
 then refer to the table for the mean pressure, which 
 will be found too low when compared with the result 
 l>y measurement. Then, this excess given by meas- 
 urement over the table is approximately the clear- 
 ance. 
 
 The editor is responsible for the above. He is 
 ;aware that it is, at best, but an approximation., owing 
 to the condition of the steam, whether wet or dry, 
 influenced, also, by the point of cut-off, pressure of 
 .steam, etc. The engineer has to adopt this mode, 
 or guess, or he may avail himself of both. 
 
 Where time and circumstances permit, the clear- 
 ance may be accurately found, if the piston is tight, 
 as follows: Put the engine on the centre, remove 
 iihe cover of the valve chest, uncover the steam- 
 port on the end where the piston is, and pour in 
 
RICHARDS STEAM-ENGINE INDICATOR. 9 
 
 water until it is filled level with the valve seat; wait 
 a few minutes, and if it maintains its level we know 
 it is tight; then draw off the water, measure or~ 
 weigh it, reduce it to cubic inches, and we have it 
 exactly. Should the piston leak, we remove it out 
 of our way; cut a segment from soft wood of suffi- 
 cient length and width to cover the port at its 
 entrance to the cylinder, fasten it in its place, and 
 fill with water as above. To this must be added 
 the clearance between piston, when on the centre 
 and cover. 
 
 Again, the clearance being known and added, 
 we compute them by measurement. If the mean 
 pressure falls short of that, we know that there is 
 a leak in the exhaust valves or piston. If it over- 
 runs that, we know the cut-off valves leak. Hence 
 the utility of the table is to make those point* 
 manifest.* 
 
Cu' 
 
 &rf 
 
 CAUFr'**' 
 
RICHARDS' STEAM-ENGINE INDICATOR. 
 DIAGRAM No. 0. 
 
 9T 
 
RICHARDS' STEAM-ENGINE INDICATOR. 99 
 
 DIAGRAM No. 1. 
 
 Scale, 12 Ibs. to the inch. 
 
RICHARDS' STEAM-ENGINE INDICATOR. 101 
 
 DIAGRAM No. 2. 
 
 200 revolutions per minute. 132 Ibs. pressure of steam cut 
 off at second notch. 
 
RICHARDS' STEAM-ENGINE INDICATOR. 103 
 
 DIAGRAM No. 3. 
 
 200 revolutions per minute. 109 Ibs. pressure of steam cut 
 off at second notch. 
 
&.' 
 
 ji> ,R 6 1 T Y 
 
 ^^(.: 
 
 
RICHARDS' STEAM-ENGINE INDICATOR. 105 
 
 DIAGRAM No. 4. 
 
 revolutions per minute. 105 Ibs. pressure of steam cut 
 off at first notch. 
 


 RICHARDS' STEAM-ENGINE INDICATOR. . 107 
 DIAGRAM No. 5. 
 
 224 revolutions per minute. 107 Ibs. pressure of steam cut 
 oft' at first not cli. 
 
RICHARDS' STEAK-ENGINE INDICATOR. 109 
 
TVEBSIT* J 
 
 \,C 
 
BICHARDS' STEAM-ENGINE INDICATOR. Ill 
 
 DIAGRAM No. 7. 
 
 A, termination of correct, expansion curve. 
 
RICHARDS STEAM-ENGINE INDICATOR. 
 
 DIAGRAM No. 8. 
 
 113 
 
RICHARDS' STEAM-ENGINE INDICATOR. 115 
 
 No. 9. 
 

 RICHARDS' STEAM-ENGINE INDICATOR. 117 
 
 DIAGRAM No. 10. 
 
BICHABDS' STEAM-ENGINE INDICATOR. 
 
 119 
 
 DIAGRAM No. II. 
 
Of THE 
 
 XJNIVEESITT 
 
BICHARDS' STEAM-ENGINE INDICATOR. 121 
 
 DIAGRAM No. 12. 
 

BICHAUDS' STEAM-ENGINE INDICATOR. 123 
 
 DIAGRAM No. 13. 
 
KICHAItDS' STEAM-ENGINE INDICATOR. 125 
 
 K 
 
 DIAGRAM No. 14. 
 
RICHARDS' STEAM-ENGINE INDICATOR. 
 DIAGRAM No. 15. 
 
 127 
 
[( UNIT - { 
 
 
B1OHARDS' STEAM-ENGINE INDICATOR. 
 
 DIAGRAM No. 16. 
 
BICHABDS' STEAM-ENGINE INDICATOR. 
 DIAGRAM No. 17. 
 

BICH ABBS' STEAM-ENGINE INDICATOR. 
 
 DZAORAXKI No. 18. 
 
 133, 
 
 ?BIT 
 
m 
 
 > 1 
 
EICIIARDo' STEAM-ENGINE INDICATOR. 135 
 
 DIAGRABI No. 19. 
 
 Back and forward. 
 
RICHARDS' STEAM-ENGINE INDICATOR. 137 
 
 DIAGRAM No. 20. 
 
tf 
 
 RICHAliDS' STEAM-ENGINE WlCA3$\f < 139 
 
 DIAGRAM No. 21. 
 
RICHARDS STEAM-ENGINE INDICATOR. 
 
 DIAGRAM No. 22. 
 
 141 
 
RICHARDS' STEAM-ENGINE INDICATOR. 
 
 143 
 
APPENDIX. 
 
 USEFUL INFORMATION. 
 
 Cement for Steam Joints. 
 
 Take a quantity of pure red lead, put it in an 
 iron mortar or on a block or thick plate of iron. 
 Put a quantity of pure white lead ground in oil; 
 knead them together until you make a thick putty, 
 then po ? md it ; the more it is pounded the softer it 
 will become. Koll in red lead and pound again ; 
 repeat the operation, adding red lead and pound- 
 ing until the mass becomes a good stiff putty. In 
 applying it to the flange, it is well to put a thin 
 grummet around the orifice of the pipe to prevent 
 the cement being forced inward to the pipe when 
 the bolts are screwed up. The more pounding the 
 better. 
 
 Another, to be used when the flanges are not 
 faced : Make the above mass rather soft and add 
 cast-iron borings, pounding in thoroughly until it is 
 sufficiently soft to spread. 
 
 Both the above are the most durable cements 
 known to the engineer. They will resist fire and 
 set in water. 
 
140 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 Another (English), said to be very good : Take 
 10 Ibs. ground litharge, 4 Ibs. ground Paris white, 
 \ Ib. yellow ochre, J oz. of hemp cut into lengths of 
 J' ; ; mix all together with boiled linseed oil to the 
 consistence of a stiff putty. Resists fire and will 
 set in water. [Pounding would improve it. ED.] 
 
 A Good Dressing for Leather Belts. 
 
 One part of beef kidney tallow and two parts of 
 castor oil, well mixed and applied warm. It will 
 be well to moisten the belt before applying it. 
 
 No rats or other vermin will touch a belt after 
 one application of the oil. It makes the belt soft, 
 and has sufficient gum in it to give a good adhesive 
 surface to hold well without being sticky. 
 
 A belt with a given tension will drive 34 per cent, 
 more with the grain or hair side to the pulley than 
 the flesh or rough side. 
 
 Rules for Calculating Belting. 
 
 This is one of the most difficult problems the 
 engineer has to solve. There are so many different 
 conditions attending the conveying of power by belts 
 that no definite rule can be given. I have found, 
 however, that where the conditions are fair to mid- 
 dling, that a belt one inch wide, running 800 feet 
 per minute, is equal to one horse power. Increased 
 width in proportion. This will do the work under 
 a safe and proper tension. There are conditions, 
 
RICHARDS' STEAM-ENGINE INDICATOR. 147 
 
 however, which might require double the above 
 width or speed. 
 
 How to make belts run on the centres of pulleys. 
 
 It often happens that a belt will persist in run- 
 ning on one side of the pulley. 
 
 In this case one or more things cause it. First, 
 one or both of them may be conical, and of course 
 the belt would run on the higher side. Second, the 
 shafts may not be parallel ; in this case the belt 
 would incline off, on the side towards where the 
 ends of the shaft are nearest to each other. The 
 remedy in this case is, to make them parallel to 
 each other by carrying the ends of the shaft towards 
 which the belt inclines, farther apart. 
 
 In giving rules for calculating the horse-power of 
 belts, we would not be understood as saying that a 
 belt will not do more than the rule would give ; on 
 the contrary, we know that double and even more 
 power may be transmitted by them by a sufficient 
 tension, which would create a ruinous amount of 
 friction and a speedy destruction of the belt. "We 
 would be understood to say that the rules give data 
 for a belt that will run with a moderate and safe 
 tension. The attempt often made to calculate the 
 work that a belt of given width and travel in feet 
 per minute without any known tension is doing, or 
 will do, is very like comparing the size of a pebble- 
 stone to a piece of chalk. The Indicator tests that 
 with certainty. 
 
148 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 The practice of putting an idler against a belt to 
 make it drive is a most pernicious one, destructive 
 alike to the belt and power ; its only merit is to 
 disguise bad engineering. 
 
 Measuring Steam used for heating. 
 
 The engineer is often called to determine the 
 amount of steam that is used to heat apartments, 
 liquids, etc. This the Indicator does not reveal 
 directly, no farther than it shows how much steam 
 it requires for a horse-power ; varied, of course, by 
 the point of cut-off and its efficiency. 
 
 Under these circumstances we have followed the 
 rule of Watt, which is to allow one cubic foot of 
 water per hour for each horse-power ; hence we 
 measure the water condensed in the heating pipes 
 in a given time, and estimate accordingly. 
 
 If it is inconvenient to reduce the water to cubic 
 feet, it may be weighed, allowing 62.5 Ibs. to the 
 cubic foot, or it may be measured by the gallon, or 
 7.48 gallons per cubic foot. 
 
 When the steam pipe enters the vessel and it dis- 
 charges the steam directly into the liquid to be 
 heated, the water then cannot be caught to be 
 measured ; in that case we measure the increment 
 of its contents, and thereby find the quantity of 
 steam condensed. 
 
RICHARDS' STEAM-ENGINE INDICATOR. 
 
 Condensation of pipes and coils. 
 
 Steam pipes in the ordinary circulation, such as 
 are used to warm buildings, when one or more run 
 around the sides of the apartment, having and 
 maintaining a temperature of 60, will condense 
 .357 Ibs. of water per hour for each square foot of 
 surface of pipe. 
 
 A coil maintaining the same temperature will 
 condense .29 Ibs. per hour per square foot of sur- 
 face. 
 
 The radiating surface of steam pipe required to warm 
 buildings and apartments. 
 
 This varies in consequence of the character of the 
 structures, the exposure, the quantity of glass, 
 the use the space required to be heated is put to, 
 climate, etc. 
 
 In the city of New York the data of calculation, 
 modified by the above-mentioned circumstances, is 
 this : 
 
 For dwellings when the pipes in form of a coil 
 are placed in the cellar and supplied with air from 
 outside one square foot of pipe surface to 50 cubic 
 feet of apartment to be warmed. 
 
 When the coil is placed in the apartment, one 
 square foot of surface of pipe to 65 cubic feet of 
 space. 
 
 In stores and warehouses, one square foot of pipe 
 surface to 175 to 200 cubic feet. 
 
150 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 In workshops, one square foot of pipe surface to 
 100 cubic feet of space. 
 
 Heating with exhaust steam is of questionable 
 economy. It is not economical, certainly, when 
 used in small pipes, in consequence of the power 
 required to force the steam through them. We 
 have seen exhaust steam used economically in work- 
 shops and factories where it is permissible to use 
 large cast-iron pipes, which present so much less 
 friction surface in proportion to the area, that the 
 power used to force the steam into them shows but 
 a small back pressure on the engine 1 or 1| lfos. per 
 square inch if the pipes are of sufficient size and 
 properly arranged. We have found the following 
 to work well in practice : 
 
 We use for the smallest, flanged pipe, without re- 
 gard to the size of the engine, 4" diameter. If it 
 is required to be over 75 feet in length, we use 5" ; 
 if over 100 feet, we use 6". 
 
 The pipes should be f thick, with flanges at 
 least 4 inches larger than the outside diameter of 
 the pipe. 
 
 These flanges should be faced so as to have a fair 
 bearing over the whole surface, and when faced, not 
 less, than f" thick, fastened with five bolts, I" diame- 
 ter. We place them, when practicable, around the 
 walls of the room, near the floor, on the sides most 
 exposed, giving them an inclination of not less than 
 one inch in ten feet ; for our joints, the cement No. 1 
 (rubber not permissible). 
 
RICHARDS' STEAM-ENGINE INDICATOR. 15J 
 
 The main exhaust pipe we carry out of the build- 
 ing, without reference to our heating pipes, except 
 to have a nozzle to carry off steam to the highest 
 end of the heating pipe. Should there be one or 
 more rooms above or below, separate pipes fron* 
 the main should be led off in the same way. The? 
 drain pipes should be at the lowest end of the pipe r 
 and J" to |" diameter. If it is desirable to let 
 only water escape, a siphon may be fixed to the- 
 end of the tail pipe, with legs of sufficient length 
 to overbalance the steam pressure, yet leaving the- 
 water by its superior gravity to escape. 
 
 The supports should be firmly fixed to the wall r 
 in perfect line with each other, that there be no> 
 bend or low place for the water to collect, which 
 would inevitably destroy the pipe. 
 
 We have used a system of pipes arranged as 
 above, for eight years, without the least attention 
 to them-. Not a joint Jias leaked. 
 
 Since the publication of the first edition, I have 
 seen exhaust steam used in 1J-" pipes with good re- 
 sult, and with but little back pressure. The arrange- 
 ment was to take the steam off the main pipe inta 
 4 4J" pipe, from the right and left side, carried 
 around on each side of the rooms. At the termina- 
 tion of each coil, a pipe 2" diameter carried off the 
 water and uncondensed steam. The back pressure- 
 shown was less than 2 Ibs. 
 
 It is not safe to allow steam pipes in contact with 
 wood. 
 
152 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 Value of Pea and Dust Coal, as compared with lump 
 of good merchantable quality, with a blast induced 
 by " Hancock's Steam Blower." 
 
 2,000 Ibs. of pea and dust, the screenings from 
 the coal-yards, have been found equal to 1,600 Ibs. 
 of lump. This is a result of several weeks' trial 
 with the same engine and boiler doing the same 
 work. 
 
 Gauge glasses, when required. -to be cleaned, 
 should have a wooden swab-stick. A metallic one 
 will cause the tube to fall to pieces inevitably, and 
 sometimes immediately. 
 
 Value of Cumberland coal as compared with 
 anthracite. Two tons (4,000 Ibs.) of anthracite 
 furnished steam for an engine seven days. The 
 same amount of Cumberland served the same 
 engine, everything else the same, eight days. 
 
 This experiment was continued with alternate 
 changes for two months. 
 
 Boiler, locomotive type, with natural draft. 
 
 When there are indications of an extraordinary 
 corrosion of the steam-boiler and its fittings, the 
 gauge-cocks and valves leak. Acid is suspected. 
 Test it by putting into a sample of the water a strip 
 of litmus paper ; if acid 'is present, the purple paper 
 will be changed to red. 
 
RICHARDS' STEAM-ENGINE INDICATOR. 153 
 
 To ascertain if iron is in solution, put into the 
 samples a few grains of tannic acid ; if iron is 
 present, it will immediately become a dark purple or 
 black. 
 
 The writer has found two cases where the wells 
 that supplied steam-boilers were poisoned by the 
 spent irickle finding its way into the wells, thence to 
 the boilers, and was detected as above. The iron 
 (sulphate) was so abundant, when a proper quantity 
 of tannin was put in, it formed a sufficient ink so 
 that the report of the examination was written with 
 it. F. W. B. 
 
 Water when converted into steam can heat about 
 6 times its own weight of well water to 212 Fahr. 
 
 JAMES WATT. 
 
 Sir Wm. Fairbairn found, by a series of experi- 
 ments, that in constructing internal flues for boilers, 
 when the pressure was from outward to the center 
 (centripetal), that as the length was increased, the 
 thickness of plate must be increased in direct pro- 
 portion. That is, if -inch plate was right for a 
 10 ft. length, if the flue was 20 ft. in length, the 
 plate must be i inch to stand the same pressure. 
 
 Dressing for an Emery Wheel, to give a fair polish, say 
 such as is usual on carpenter's tools. 
 
 The tool has been surfaced on a wheel covered 
 with No. 60 emerv. Take another wheel covered 
 
154 RICHARDS' STEAM-ENGINE INDICATOR. 
 
 same No., and rub on a composition of flour, 
 emery and beeswax. Set the wheel running and 
 hold on a flint ; again rub on the composition and 
 .again the flint, until it gives the polish required. 
 
 To make the composition, melt the wax with a 
 gentle heat ; stir the emery in until it is thick ; 
 Temove the heat, and keep up the stirring until it is 
 .-so cool that the emery won't fall to the bottom. 
 
 The wheel must be kept nicely balanced, or the 
 polish will be cloudy. F. W. B. 
 
 To Cool Off a Hot Bearing. 
 
 Take off the top box, and while the shaft is slowly 
 turning, put on white-lead ground in oil from the 
 leg. When the lead is seen coating the bearing as 
 it turns slowly, it shows that the lead has interposed 
 itself between the two surfaces and will cool down, 
 when the ordinary lubricant may be resumed. 
 
 F. W. B. 
 
 Water j Scales the Boiler. Lime is suspected. 
 
 TEST. Into a tumbler containing the suspected 
 water put 8 or 10 grains of oxalic acid ; if lime is 
 present, the water will become milky, and after 
 standing quiet awhile, the lime will be precipitated 
 (oxalate of lime). 
 
 Should the precipitate not show itself, add a little 
 ammonia, which is a more delicate test. If no pre- 
 cipitate is shown, it is not lime that forms the scale. 
 
 F. W. B. 
 
RICHAliDS' STEAM-ENGINE INDICATOR. 155 
 
 For Calculating the Horse-powers of a Given Quantity 
 of Water in a Given Time, 7,000,000 gallons of Water 
 passing through the Turbine in 60 hours. 
 
 KULE. Multiply the fall in feet by .3682. The 
 product is the horse -powers, net. This is a unit. If 
 there is more or less water, or more or less time, the 
 horse-power developed will be more or less in direct 
 proportion. 
 
 From testimony of J. B. FRANCIS, C. E. 
 
 ANOTHER RULE. 8.8 cubic feet of water per second 
 falling one foot is equal to one horse-power. 
 
 From testimony of C. HERSCHEL, C. E. 
 
 The Inspirator 
 
 supplies the steam-boiler with water cheaper than the 
 steam-pump. F. W. B. 
 
 Memorandum. 
 
 It is bad practice to pack the joints of steam- 
 chests, cylinder-heads, etc., with rubber ; in fact, any 
 joint that is exposed to heat, as the sulphur used in 
 volcanizing, disintegrates the cast iron and erodes 
 the bolts inevitably in tim?. It may be tolerated in 
 the manhole of the boiler. F. W. B. 
 
RICHARDS-THOMPSON'S STEAM-ENGINE INDICATOR. 
 
 156 
 
SUPPLEMENT 
 
 TO THE 
 
 PORTER-BACON TREATISE ON THE 
 
 EICHARDS STEAM-ENGINE INDICATOR; 
 
 BEING NOTES ON THE 
 
 RICHARDS-THOMPSON INDICATOR, 
 
 THE AMSLER POLAR-PLANIMETER AND THE PANTOGRAPH, 
 AS USED IN CONNECTION WITH THE INDICATOR. 
 
 By F. W. BACON, M. E., 
 Member of the American Society of Civil Engineers. 
 
 1879. 
 
 157 
 
THE 
 
 RICHARDS-THOMPSON 
 
 STEAM-ENGINE INDICATOR, 
 
 rTIHE constant demand for high piston speed of 
 -A- stationary and locomotive engines, has outrun 
 the capacity even of the Kichards instrument, and 
 rendered it imperative, if we would have a correct 
 result, that an instrument be produced that would 
 meet the call. Therefore, "necessity being the 
 mother of invention," the patentee has given us the 
 instrument which is all that can be desired. It is 
 believed that it will give correct results under any 
 attainable speed of a steam-engine. It will be ob- 
 served that Mr. Thompson's improvement mainly 
 consists in reducing the weight 43.65 per cent of 
 the parallel motion, by reducing the number of 
 vibrating pieces, thereby reducing the tendency to 
 make wavy lines in both steam and expansion. By 
 the new arrangement the instrument is lighter and 
 more compact, qualities that will be fully appreciated 
 by the engineer. 
 
 159 
 
160 RICHARDS-THOMPSON INDICATOR. 
 
 With these improvements, and the facilities pro- 
 vided for the attachment of the instrument, it is 
 obvious that the engineer in charge should be edu- 
 cated to its use, and required to make weekly reports 
 of power indicated and fuel expended. 
 
 The Indicator is the light to the engineer's eye : 
 without it he gropes in the dark ; he can't set his 
 valves correctly ; he has no mode of measuring the 
 power even approximately without it ; hence he can 
 make no comparative test of fuel used and power 
 eliminated ; he may be burning 10 or 15 Ibs. of coal 
 per hour per horse-power, when he should burn but 
 2J to 3 Ibs. per hour per horse-power ; a most scan- 
 dalous and wicked waste of fuel. 
 
 The locomotive presents a great field for its appli- 
 cation, though as yet but partially cultivated. Those 
 master mechanics who have had the courage to apply 
 it, and have followed its indications, have shown 
 most curious results, which have prompted a change 
 in valve gear, valve settings, enlargements of ports 
 and thoroughfares, an increase in the areas of noz- 
 zles, etc. 
 
 The following diagram (No. 1), taken by J. A. 
 Lauder, Esq., M. M., of the Northern (N. H.) Rail- 
 road, is one of the many taken from engines under 
 his charge, which he has kindly furnished me ; it is 
 not an exceptional one. It will, however, be hard to 
 find its superior. To attain this excellence, he fol- 
 lowed the dictation of the Indicator. Its mate from 
 the other end is o.fac-simile. 
 
BICHARDS-THOMPSON INDICATOR. 
 
162 RICHARDS-THOMPSON INDICATOR. 
 
 The LOCOMOTIVE, MOGUL PATTERN, of the following 
 description : 
 
 WOOD BURNER. 
 
 Cylinders, 17 x 24 in. ; diameter of wheel, 54 in. ; 
 admission ports, 16x1^ in.; exhaust ports, 16 x 2 j 
 in.; outside lap, -J in.; inside lap, -J- in.; travel of 
 valve, 5 in.; lead full gear, ^ in. ; boiler pressure, 
 1 30 Ibs. ; cutting off at 12 in. ; exhaust nozzles, two, 
 3 in. diameter ; revolutions, 50 per minute ; scale of 
 instrument, 60 to one inch. 
 
 DIAGRAM NO. 2 
 
 is introduced to supply information to beginners, who 
 will sometimes, when getting diagrams from engines 
 without any or but little load, find the expansion 
 curve fall below the atmospheric line, showing a 
 partial vacuum behind the piston, and are often at 
 loss how to account for, or what to do with it. 
 The writer does not remember having seen it men- 
 tioned in any of the books, and having known of 
 some rather ridiculous blunders made in disposing 
 of it, ventures to take it up and explain it, though it 
 may seem to the expert unnecessary. 
 
 This " loop below " is made by the advancing piston 
 passing the point due to reducing the volume of steam 
 by expansion to the atmospheric pressure at that 
 point the expansion-curve crosses the atmospheric 
 line, and might, under certain circumstances, create 
 
RICHARDS-THOMPSON INDICATOR. 
 
 nearly a perfect vacuum, were it not for the presence 
 of water, which re-evaporates and partially fills the 
 space. 
 
 In treating this loop, it must be measured out, the 
 same as any back or negative pressure. It don't 
 suffice not to measure it in measure the diagram 
 without including it, then measure it, and deduct it 
 from the sum of first measurement. This " loop " 
 incidentally serves a very important purpose, inso- 
 much as its presence shows that there is no leak 
 either in the valves or piston. 9 
 
EICHAKDS-THOMPSON INDICATOR. 
 
 DIAGRAM No. 2. 
 
RICHARDS-THOMPSON INDICATOB. 165 
 
 The following diagram (No. 3) is introduced as 
 one of the most perfect that is obtained from a high- 
 pressure, non-condensing engine. It was taken with 
 the Thompson Indicator, actuated by the Panto- 
 graph, from " The Brown'' engine, 16" x 42 "x 60 
 revolutions, exhibited at the Fair of the Massachu- 
 setts Charitable Mechanic Association. When we 
 consider the speed of the piston, 420 ft. per minute, 
 the steam pressure, 67 Ibs., scale 40, we think un- 
 commonly perfect lines are shown, especially the 
 steam line and expansion curve. It shows also a- 
 most prompt and perfect action of the admission and 
 eduction valves ; the point of cut-off is sharp, 
 decided, and unmistakable, qualities that will be 
 fully appreciated by the engineer. 
 
 It is one of many hundred diagrams taken by 
 the writer from the engine during the exhibition, 
 all with the same characteristics. 
 
 Should any one wish to make the theoretic curve 
 around the diagram, we give in addition to the above 
 data the clearance, 2 per cent. 
 
166 
 
 RICHARDS-THOMPSON INDICATOR. 
 
 DIAGRAM No. 3- 
 
RICHARDS-THOMPSON INDICATOR. 167 
 
 For reducing the motion of the piston to the 
 required length of the diagram, there are many 
 devices. The one most in use is a strip of board 
 suspended from the ceiling above, or carried off 
 horizontally, as circumstances dictate, and it often 
 requires considerable ingenuity to effect it without 
 too much cost ajid delay. The pendulum should be 
 not less than one and one-half the length of the piston- 
 stroke from the point of suspension to the point of 
 attachment to the cross-head ; if longer, say twice 
 the length of the stroke, it is better. 
 
 To find the point of attachment of the line leading 
 off to the indicator, the following is the 
 
 RULE. Divide the length of piston-stroke in inches 
 by the required length of the diagram ; divide the 
 length of the pendulum in inches by the above quo- 
 tient, and this quotient is the distance in inches from 
 the point of suspension to the point of attachment 
 of the line, approximately. 
 
 EXAMPLE. Stroke of piston, 36". Length of re- 
 quired diagram, 4.5". Length of pendulum, 54". 
 
 Then 36"-=-4.5 8. 54^8 = 6.75. 
 
 Or, 4.5 ) 36.0 ( 8 
 
 36.0 
 
 8 ) 54 ( 6.75" from point of suspension to 
 48 attachment of line. 
 
 60 
 56 
 40 
 
168 RICHARDS-THOMPSON INDICATOR. 
 
 Tliis is approximate, but not mathematically cor- 
 Tect, owing to the arc of a circle described by both 
 ^points of attachment, yet is considered sufficiently 
 .accurate for practical purposes. The pantograph 
 :gives us a correct result. 
 
 On page 24 of the "Treatise," and onward, the 
 question of the mode of giving mption to the Indi- 
 cator is discussed. Since that was published, there 
 has been a new mode applied, which is invaluable, 
 insomuch as it is mathematically correct, can be 
 applied in almost any case, renders long lines and 
 carrying pulleys unnecessary, is compact and port- 
 able, being when folded about 18" long by 3" x 5". 
 It is known as the Indicator Pantograph. It is fur- 
 nished with or without the instrument, when 
 required. It is an old, well-known device, applied 
 to a new purpose. 
 
 If the Indicator is applied to the side of the cylin- 
 der, it enables us to use short cords, without the use 
 of carrying pulleys to lead the cord to the Indicator. 
 We would advise the operator to use the Raided 
 cord, as it is far less elastic. 
 
 A medal was awarded to the Indicator Pantograph 
 ut the late Mechanics' Fair of Massachusetts. 
 
 Since the second edition of the Treatise was pub- 
 lished, an instrument for measuring and computing 
 diagrams has been introduced. It can be used also 
 to measure any other irregular or regular form 
 within its compass. It is known as 
 
AMSLEK'S POLAR-PLANIMETER. 
 
170 AMSLER'S POLAB-PLANIMETER. 
 
 Its use greatly diminishes liability to error; and 
 the great aid it affords to the quick and accurate 
 computation of diagrams, renders its use indispensa- 
 ble, especially to engineer experts who are employed 
 to make special tests of long duration, where a thou- 
 sand, more or less, of diagrams are to be calculated. 
 Also to the ordinary engineer who takes indicator 
 cards for the purpose of adjusting his valves and 
 calculating the power of his engine ; no matter what 
 the shape of the diagram is, whether the lines and 
 curves are straight or jagged, waving or serrated, 
 the instrument follows them accurately and gives a 
 correct measurement. 
 
 It will be seen by the engraving that the instru- 
 ment has two legs, with a joint at the top like a pair 
 of dividers, with the right-hand leg shorter than its 
 mate ; to the short leg is attached a cylinder (7, with 
 a projecting flange, which revolves freely on its axis. 
 The cylinder is divided into ten grand divisions, and 
 marked 1234567890. Now as 
 the wheel rolls around, each one of these divisions 
 represent one square inch. Each one of these grand 
 divisions is subdivided into ten spaces representing 
 one tenth of a square inch. But this is not fine 
 enough ; we want to measure hundredths. To effect 
 this, we use the Vernier scale, which in this case is a 
 segment of a circle, same diameter as the cylinder, 
 whose edges are put in juxtaposition with each other, 
 but allowing the latter to revolve without touching. 
 This segment has one grand division just correspond- 
 
AMSLEB'S POLAR-PLANIMETEE. 171 
 
 ing to nine of the subdivisions on the cylinder. This 
 grand division is subdivided into ten spaces, and 
 marked 510. This segment is firmly fixed to 
 the head of the instrument, so that the edge of it 
 exactly corresponds with the edge of the revolving 
 cylinder. It is called the Vernier scale. With these 
 relative positions, the graduations come opposite 
 each other, but as the spaces are not the same on 
 each, it is evident that but one mark on each can be 
 opposite. 
 
 HOW TO USE THE INSTRUMENT. 
 
 Fasten the diagram to your drawing-board by pins 
 or springs ; alongside of it a half-sheet of fine 
 glazed paper for the wheel of the instrument to move 
 on. Place the needle-point A at a proper point on 
 the paper and the tracer B on a marked point of the 
 outline of diagram D; then raise the wheel C and 
 turn it until on the cylinder corresponds with 
 on the vernier E, press lightly with a finger of the 
 left hand on the point A, and with the fingers of the 
 right hand take hold of the top of the tracer B, and 
 carefully follow the line in the direction of the hands 
 of a watch until it reaches the starting-point. W T e 
 now read the instrument. We find that on the 
 cylinder has passed on from on JS 9 and 2 has passed 
 it. We write 2 (2 inches). We follow it by seeing 
 how much 2 has passed. We find it shows four 
 marks on the cylinder and a little more. We write 
 
172 AMSLER'S POLAR-PLANIMETER. 
 
 4, which is r %. We now look for a mark on the 
 cylinder that corresponds with one on the Vernier E. 
 In this case we find the second mark from Vernier 
 corresponds with a mark on the cylinder. We write 
 2, being T f 7 . The reading then is thus, 2.42 square 
 inches, area of diagram. We now measure the length 
 of the diagram in inches, parallel to the atmospheric 
 line, which in this case is four inches. We now divide 
 the area by the length ; the quotient is the mean 
 height in inches of the diagram, which is .605 inches ; 
 this we multiply by the scale of the indicator, which 
 is thirty to the inch in this case ; the product gives 
 us 18.15 Ibs. mean pressure on each square inch of 
 the piston. The sum is thus : 
 
 4 ) 2.42 
 .605 
 
 30 
 
 18.150 Ibs., mean pressure. 
 Expressed thus : 
 
 2.42 -f- 4 = .605 x 30 = 18.15. 
 
 N. B. If the diagram should measure more or 
 less than four inches in length, divide by what it 
 may be ; so also with the indicator scale, multiply 
 by what it is. 
 
 If the figure to be measured is a plan drawn to a 
 scale, we proceed as above to get the square inches ; 
 we find in this case the reading to be nine square 
 inches, our scale is one inch to one foot, which is 
 
AMSLER'S 'POLAR PLANIMETER. 173 
 
 one-twelfth size ; to raise this to full size, we multi- 
 ply the reading by the square of the ratio, thus : 
 12 x 12 = 144 x 9 = 1296 square inches' full size. 
 Same in all other scales. Square the denominator and 
 multiply the product by the reading ; the product is 
 full size in square inches. 
 
 In giving in the foregoing direction how to read 
 the record of the instrument, we have supposed that 
 the operator was not familiar with the Vernier scale, 
 hence we advised him to put and to correspond ; 
 this is right, though not necessary. 
 
 FOR EXAMPLE : The instrument is in place, the 
 reading is 1.14, the tracer is carried around the out- 
 lines as directed, and the reading is 3.56 ; now we 
 subtract the first reading from the second, thus : 
 
 3.56 - 1.14 = 2.42 3.56 
 
 1.14 
 2~42 
 
 This the learner will soon get familiar with. 
 
 THE CARE OF THE INSTRUMENT. 
 
 It is exceedingly delicate ; it will not bear banging 
 like a horse-shoe, nor suffered to become foul. Care 
 must be taken that he roller-wheel revolves perfectly 
 free end yet no looseness in its 'pivots, the same in all 
 the joints. Take great care that the roller-wheel 
 and vernier-scale don't get msty or foul with dirt. 
 Oil the movable points with porpoise oil and none 
 
174 
 
 AMSLER S POLAR-PLAIslMETER. 
 
 other. It can always be procured at the watch or 
 clock maker's. This is imperative, if correct results 
 are to be attained. 
 
 The above description is believed to be sufficient 
 for all practical purposes. For a mathematical ex- 
 position, disclosing the scientific principles on which 
 it acts, see Spon's Dictionary. 
 
 For convenience in using the common rule to 
 measure the length of the diagram, we have calcu- 
 lated the following table, reducing the common 
 fraction to decimals : 
 
 Com. 
 Prac. 
 
 Decimal.) 
 
 Com. 
 Frac. 
 
 Decimal. 
 
 Com. 
 Frac. 
 
 Decimal. 
 
 Com. 
 Frac. 
 
 Decimal. 
 
 A 
 
 .0312 
 
 A 
 
 .2812 
 
 H 
 
 .5312 
 
 
 
 .7812 
 
 yV 
 
 .0625 
 
 A 
 
 .3125 t V 
 
 .5625 
 
 ft 
 
 .8125 
 
 A 
 
 .0937 
 
 H 
 
 .3437 
 
 H 
 
 .5977 
 
 H 
 
 .8437 
 
 t 
 
 .1250 
 
 t 
 
 .3750 
 
 1 
 
 .6250 
 
 i 
 
 .8750 
 
 A 
 
 .1562 
 
 if 
 
 .4062 
 
 H 
 
 .6562 
 
 
 
 .9062 
 
 A 
 
 .1875 
 
 A 
 
 .4375 
 
 H 
 
 .6875 
 
 H 
 
 .9375 
 
 A 
 
 .2187 
 
 H 
 
 .4687 
 
 If 
 
 .7187 
 
 
 
 .9687 
 
 i 
 
 .2500 
 
 i 
 
 .5000 
 
 f 
 
 .7500 
 
 It 
 
 1.0000 
 
 From the above description and examples it will 
 be seen that calculating the 'diagram is reduced to 
 the minimum of time and maximum of accuracy. 
 We dispense with the use of the parallel rule, with 
 
AMSLER'S POLAE-PLANIMETEB. 175 
 
 ten or more measurements, with adding up a long 
 column of figures and the required divisions, to get 
 a doubtful result at best, and substitute the described 
 manipulation of the instrument ; note its reading, 
 and by the use of fourteen figures get a positively 
 accurate result. 
 
 DIRECTIONS. 
 
 Before taking the diagram, shut off the supply of 
 whatever lubricant is used in the cylinder of the 
 engine, which is usually some gummy oil or other 
 villainous compound, that gums the piston and 
 cylinder of the instrument, rendering its action 
 dull, showing curves where there should be angles, 
 and retarding its free action generally. 
 
 Oil the piston of the instrument often when in use, 
 and see. that the cylinder is smooth and clean, for 
 on these points depend largely the integrity of its 
 action and correctness of the diagrams. 
 
 TO SELECT A SPRING FOR A GIVEN PRESSURE. 
 
 RULE. Divide the boiler pressure by 2.5; th 
 quotient is the proper number of spring. 
 
 EXAMPLE. Boiler pressure, 75 Ibs. -f- 2.5 = 30. 
 
 It is good practice to use as low number as will do 
 for the pressure, so as to get the diagram on a large 
 scale. 
 
INDEX TO SUPPLEMENT. 
 
 PAGE 
 
 Diagram No. 1. Showing the Action of the Instrument, 
 
 Thompson's Indicator 160-161 
 
 Diagram No. 2. With Explanation of the " loop below," 162 
 
 How to Treat it 163 
 
 Diagram No. 3. Its Character 165 
 
 Kule for Reducing Motion of Piston to required Length 
 
 of Diagram 167 
 
 Indicator Pantograph 168 
 
 Amsler's Polar-Plani meter with Cut 168-169 
 
 Description of the Instrument 170 
 
 How to Use it 171 
 
 Examples 172-173 
 
 Care of the Instrument 173-174 
 
 Table for Reducing Common Fractions to Decimals 174 
 
 Directions 175 
 
 How to Select a Spring for a Given Pressure 175 
 
INDEX. 
 
 PAGB 
 
 American Editor's Preface 7 
 
 Nature and Use of the Indicator. 9 
 
 Mode of proceeding to Find the Power a Tenant Uses. . 9 
 
 Analysis of Diagram No. 1 14 
 
 Truth of the Diagram 16 
 
 Conditions of a Correct Diagram . . . 16 
 
 Errors Liable 17 
 
 General Construction of the Indicator 18 
 
 Metallic Pencil 19 
 
 List of Springs 20 
 
 Practical Directions for Applying and Taking Care of the 
 
 Indicator 21 
 
 Giving Motion to the Paper 24 
 
 From what Points to Derive the Motion 25 
 
 " " " " on Locomotves. . 27 
 
 on Oscillating En- 
 gines 28 
 
 How to Take a Diagram 29 
 
 To Connect the Cord 30 
 
 To Take the Diagram 31 
 
 Notes on Diagram 33 
 
 How to Keep the Indicator in Order 34 
 
 Note on the Importance of Proper Oil 34 
 
 How to Change the Springs 36 
 
 " Barrel Springs 36 
 
 1 ' Ascertain the Power Exerted by the Engine ... 37 
 
 On Diagrams from Condensing Engines 40 
 
 177 
 
INDEX. 
 
 PAGE 
 
 Power Exerted by Engines as Per Diagram No. 1, with 
 
 Example 43 
 
 On Diagrams from Non-condensing Engines Example. . 46 
 To Measure from the Diagram the Amount of Steam 
 
 Consumed 49 
 
 Observations on the Several Lines of the Diagram 51 
 
 Classifications of Engines, Steam Line 52 
 
 Full Stroke, Lap, Link, Independent, by Action of Gover- 
 nor on the Cut-off Valve, and according to the Work 
 
 by Throttle 52, 53 
 
 Prof. Tyndall's Experiments 57 
 
 Importance of Cutting-off quickly 60, 61 
 
 To find Mean Pressure by Hyperbolical Logarithms. . . 62 
 
 Remarks of the Editor Examples 68, 64 
 
 Exhaust Line and Line of Counter Pressure 64 
 
 Compression Line 65 
 
 Theoretic Curve and its Uses ; How it is made ; Clear- 
 ance Defined 67, 68 
 
 Cards from a Caloric Engine 72 
 
 Trip from Wilmington to Philadelphia on Locomotive 
 
 No. 50, with Method of Operation 73 
 
 Valve Setting How to set a Slide Valve 78 
 
 Remarks on Table V. How to find if the Engine is 
 tight, and how to find the Clearance 94 
 
 TA.BLES. 
 
 Table No. I. Areas of Circles 81 
 
 Circumferences of Circles 86 
 
 Table No. II. Showing Weight of the Atmosphere at 
 
 different Heights of the Barometer 89 
 
 Table reducing common fractions to decimals 174 
 
INDEX. 179 
 
 PAGE 
 
 Table No. III. Showing the Elastic Force of Steam at 
 
 Different Temperatures 90 
 
 Table No. IV. Logarithms 92 
 
 Table No. V. Steam Used Expansively. Average Pres- 
 sure in Ibs. per square inch for the Whole Stroke. . . 93 
 
 Diagrams 97-143 
 
 Diagram No. 1. Supplement 161 
 
 " 2. " 164 
 
 " 3. " . 166 
 
 Cement for Steam Joints 145 
 
 A Good Dressing for Leather Belts 146 
 
 Rules for Calculating Belting 146 
 
 How to Make Belts run on Centres of Pulleys 148 
 
 "Idlers" 149 
 
 Measuring Steam used for Heating 149 
 
 Condensation of Pipes and Coils . . 149 
 
 Radiating Surface of Steam-pipe required to Heat Build- 
 ings and Apartments . 148 
 
 Comparative Value of Pea and Dust Coal with Lump 152 
 
 " Cumberland and Anthracite 152 
 
 Cleaning Gauge of Glasses 152 
 
 Extraordinary Corrosion 152 
 
 To Ascertain if Iron is in Solution 153 
 
 Quantity of Steam to Heat a Given Quantity of Water. . 153 
 
 Farbairn's Experiment on Boiler Flues 153 
 
 Dressing for Emery Wheels 153 
 
 To Cool Hot Bearings 154 
 
 Scale in Boilers 154 
 
 Lime is Suspected. Test 154 
 
 Rule for Calculating Horse-powers of Water . .^ 155 
 
 The Inspirator .. 155 
 
 Rubber Steam Joints (. . T. 155 
 
ANOTHER edition, the fourth, of this work is called for, 
 which indicates that our working engineers are becoming 
 educated in the use of the Indicator to their great advantage 
 and the interest of their employers, who, as a rule, appreciate 
 the great advan- 
 tages made man- 
 ifest and tangi- 
 ble by its intelli- 
 gent use. Com- 
 bined with the 
 Fairbanks Scale 
 it shows them 
 unerringly how 
 much power they 
 get for a dollar 
 from the various 
 kinds of fuels in 
 use. 
 
 In our third 
 edition, page 168, 
 we noted the 
 pantograph, 
 which is now in 
 general use, 
 which is shown 
 in the engraving. 
 It is shown to be 
 connected with 
 the old-style hor- 
 izontal cross- 
 head, links held 
 fast by the lock- 
 nut of the gib 
 
 adjusting screw. THE PANTOGRAPH. 
 
 It will be seen that the link is by its joints capable of being 
 expanded or contracted in its opening from to 3)", g 
 
that it will embrace the largest Corliss vertical crosshead to 
 the smallest adjusting or other screw. There are some small 
 pieces go with it, to adjust and attach it, which the engineer 
 will at once see the 
 use of in its applica- 
 tion under the va- 
 rious kinds of en- 
 gines and positions 
 he finds them. We 
 have never seen an 
 engine that we could 
 not get an attach- 
 ment with it in ten 
 minutes. This link 
 attachment is a 
 small, simple affair, 
 can be carried in 
 the pocket, and is 
 equally convenient 
 and useful with the 
 ordinary mode of 
 reducing the motion 
 as with the panto- 
 graph. The link at- 
 tachment is applic-* 
 able to all engines 
 horizontal, vertical, 
 inclined-rotary, or 
 oscillating. It is 
 known as BACON'S 
 PATENT PANTO- 
 GRAPH ATTACHMENT. 
 Notwithstanding 
 the facilities fur- 
 nished by the above 
 attachment in get- 
 ting the motion 
 from the crosshead 
 or other proper 
 point, still another 
 difficulty often oc- 
 curs which gives us 
 more or less trouble 
 to manage, and that is to lead the line off in the proper direc- 
 tion so as to give a correct result. Steam-pipes, exhaust-pipe^ 
 
and other obstructions incident to the structure of the engine, 
 often the contracted space allotted to it, and unforeseen awk- 
 ward conditions oft- 
 en with the old ar- 
 rangement,, render it 
 impossible to get the 
 line to run parallel 
 with the piston-rod 
 (a sine qua non) 
 without too many 
 carrying pulleys or 
 chafing the lines, 
 which must in any 
 event be avoided if 
 we would have cor- 
 rect results. Hap- 
 pily the patentee has 
 helped us out of this, 
 as the accompanying 
 cats will show. 
 
 Fig. 1 shows the 
 original Thompson 
 instrument. 1A 
 shows the swivel- 
 base and carrying- 
 pulleys. This 'base 
 can swivel around to 
 the right or left, but 
 the pulleys remain 
 upright, which is 
 sometimes exceed- 
 ingly inconvenient. 
 
 The improved 
 swivel-base is shown 
 attached in Fig 2, 
 and detached in Fig. 
 2B. 
 
 It will be seen that 
 by its construction 
 a swivel of itself, 
 which can be set and 
 held by the thumb- 
 screw at any angle 
 to suit the line and give it a proper direction without dis- 
 torting the diagram or abraiding the line. 
 
F. W. BACON, M. E., 
 
 FURNISHES INSRUMENTS, 
 AND GIVES INSTRUCTION IN THEIR USE. 
 
 MANUFACTURERS, and others using Steam-Engines, can, by apply- 
 ing the INDICATOR, ascertain the condition of their Engines ; the 
 power required to do their work, or any portion thereof ; the economy 
 of fuel expended, when compared with power developed. 
 
 The undersigned makes a specialty of this branch of engineering, 
 and will wait on any party who desire his services. 
 
 Special attention given to the erection of Steam-Engines and 
 Machinery, Shafting and Belting. 
 
 Will attend to laying out works, and make plans and estimates. 
 
 Parties wishing to burn shavings, saw-dust, and other light fuels, 
 can have their furnaces constructed so as to consume the smoke and 
 gases therefrom, at a moderate cost. 
 
 F. W. BACON, Consulting Engineer, 
 
 33 Bromfield Street, Boston. 
 
 AGENT FOR 
 
 HANCOCK'S STEAM BLOWER, 
 
 The cheapest, best, and most efficient 
 Blower known. 
 
 NO OILING, NO SHAFTING, NO PULLIES, NO BELTING 
 ^QV_J^ REQUIRED. 
 
 For burning screenings, re-heating in rolling mills, and hot nut- 
 presses it has no substitute. 
 
 Guaranteed to give entire satisfaction or no sale. 
 
 
Lane's Improvement Inside View. 
 
ORIGINAL STEAM GAUGE Co. BUSINESS ESTABLISHED IN 1851. 
 INCORPORATED IN 1854. 
 
 SOLE MANUFACTURERS OF THE 
 
 THOMPSON IMPROVED INDICATOR. 
 
 THE THOMPSON IMPROVED INDICATOR. 
 
 BOURDON STEAM GAUGE, 
 
 WITH LANE'S IMPROVEMENT. 
 
 Amsler's Polar Planimeter and the Pantograph, 
 
 36 Cliardon Street, Boston, Mass. 
 
 J. C. BIAISDELL, E. BtRT PHILIIPS, H. K. MOOBE, 
 Pres. Treas. Supt, 
 
FOR 
 
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JAftYIS PATENT FUBNACE 
 
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 STEA.M BOILERS. 
 
 
 Economy of Fuel, with increased capacity of steam-power. Like the 
 SIEMENS STEEL PROCESS, it utilizes the waste gases with hot air on 
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 Manufactured by the 
 
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 BOSTON, MASS. 
 
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 LONDON, ENG-. 
 
Organised 1366. 
 
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1852. 
 
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BOSTON, MASS. 
 
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 And all kinds of 
 
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Established 1864. 
 
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 PLYMPTON (Prof. GEO. W.) The Star-Finder, or Plani- 
 ! phere, with Movable Horizon. Printed in colors on fine 
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 POCKET LOGARITHMS, to Four Places of Decimals, includ- 
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 Natural Sines, Tangents, and Co-Tangents. i6mo, boards, y> 
 Morocco ................................................... I oo 
 
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 ing Vessels propelled by Sail or Steam. Including a chap- 
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 illustrations, cloth .......................................... 5 OO- 
 
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 - Chemical Examination of Alcoholic Liquors. A Manual 
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 designed for the use of Academies, Colleges, and High- 
 
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 them. New edition, revised and enlarged, and illustrated 
 by 269 illustrations on wood. Crown 8vo, cloth ............. 3 o& 
 
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 M.D. 8vo, cloth .......................................... 225 
 
 RANDALL (P. M.) Quartz Operator's Hand-Book. New edi- 
 
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