GIFT OF 
 
of the Department 
 OF 
 
 antf f 
 
THE AMERICAN 
 Thompson Improved Exposed Spring Indicator 
 
 with the 
 
 New Improved Detent Motion 
 
TWENTY YEARS 
 
 WITH THE 
 
 INDICATOR. 
 
 BEING A 
 
 PRACTICAL TEXT-BOOK FOR THE ENGINEER OR THE STUDENT, 
 
 WITH NO COMPLEX FORMUL/E. 
 
 With many illustrations and rules as to the best way to run any Steam Engine to get the moat 
 
 economical results. How to adjust Valves and Valve Motions correctly. Full directions 
 
 for working out Horse Power \ the amount of Steam or Water per Horse Power, Econ- 
 
 trtny of Fuel. The author's original and correct application of the Theoretical 
 
 Curve, to show exactly where the steam valve closed, and whether valves leak 
 
 or not; extended directions for attaching the Indicator, what motions to 
 
 use and those not to use. Full directions for computation 
 
 of Power by Planimeter and other methods. 
 
 with many tables and hints. 
 
 NEWLY ARRANGED AND COMPLETE IN ONE VOLUME, 
 
 TWENTY-FIRST THOUSAND 
 
 BY THOMAS PRAY, JR., 
 
 CONSULTING AND CONSTRUCTING AND CIVIL AND MECHANICAL ENGINEKK, 
 MEMBER OF VARIOUS SOCIETIES, ETC 
 
 BOSTON : 
 
 AMERICAN STEAM GAUGE AND VALVE MFG. CO. 
 208-220 CAMDEN STREET. 
 
 1909. 
 
Engineering 
 Library 
 
 VOL. I. COPYRIGHT 1882. 
 
 COPYRIGHT AND ALL INTEREST TRANSFERRED TO 
 
 THOS. PRAY, JR., 1885. 
 
 VOL. II. COPYRIGHTED 1885, BY 
 
 THOMAS PRAY, JR., BOSTON, MASS. 
 
 ALL RIGHTS RESERVED. 
 
 BOTH VOLUMES IN ONE. 
 
 COPYRIGHTED BY THOMAS PRAY, JR. 
 
 BOSTON, MASS. 
 
 1888. 
 
 COPYRIGHT AND ALL INTEREST TRANSFERED TO 
 
 AMERICAN STEAM GAUGE AND VALVE MFG. Co. 
 
 208-220 CAMDEN STREET, 
 
 BOSTON, MASS. 
 
 1908. 
 
 PRESS OF 
 
 A.CHEY & GORRECHT 
 LANCASTER, PA. 
 
DEDICATION OF VOL I. 
 
 THIS work is respectfully dedicated, with the highest feelings of regard, to 
 my friend, J. M. ALLEN, of the Hartford Steam Boiler Insurance and Inspec- 
 tion Company, for his high value of personal integrity, and for the good he 
 has done, and is doing, to protect the lives of stationary steam engineers and 
 the property in their and his charge, 
 
 BY THE AUTHOR. 
 
 DEDICATION OF VOL II. 
 
 THIS volume is dedicated, with every sense of respect and the highest 
 regard, to that class of men who are everywhere working to better inform 
 themselves, to better their condition by knowledge and fidelity, and to secure 
 greater safety in the steam power in their control, and consequently better 
 results to their employers, and greater safety to human life everywhere 
 THE WORKING ENGINEERS Marine, Locomotive or Stationarywher- 
 ever they are, in the humble hope that it may contribute to their benefit, 
 from an extended experience of one who is practically one of them. 
 
 THE AUTHOR. 
 
 JANUARY 1st, 1885. 
 
 274759 
 
PREFACE TO VOL. I. 
 
 WHEN the author commenced a series of articles on the Indicator in the 
 BOSTON JOURNAL OF COMMERCE, it was only with an idea of writing a few 
 articles in number, for the purpose of showing up some of the most generally 
 found defects oi the builders of steam engines, defects in practice, and to 
 explain, in as simple a way as possible, how to adjust, or at least how to over- 
 come these defects, so far as the defects of building would allow, and make a 
 more economical use of steam. The subject, however, grew on the author's 
 hands, and, rather to his disappointment, a great deal of inquiry was elicited. 
 The articles were continued far beyond his own ideas, originally, and, as the 
 paper was growing rapidly in circulation, hundreds of subscribers were added 
 who could not procure the first of the series. Within the first four or five 
 months inquiries began to come in asking us if we would not print the articles 
 in book form. It was a year or more after the appearance of the first article of 
 the series before time could be given to their revision for the purpose of re- 
 publication in book form. Meantime the name of the paper had been changed 
 to COTTON, WOOL AND IRON, and the subscription list was increasing faster 
 than ever. All this required new quarters, and we were obliged to move in the 
 very midst of the preparation of this book ; and the book was still further de- 
 layed some two or three months on account of having to add to our plant for 
 printing the paper. This, in brief, is how this book came to be printed. It is 
 offered to the public with the full knowledge that there are many little inac- 
 curacies, arising from the fact that the author has been doing the work of two 
 or three men. Aside from having the full management and editorial charge 
 of the paper, (which is no easy job,) his daily consultations have been large, 
 being obliged at times to travel several hundred miles per week, which, 
 together with the charge as consulting engineer of a number of large steam 
 plants and cotton mills, has made it next to impossible for him to sit down for 
 more than an hour without interruption or being obliged to drop the work 
 entirely for days together. 
 
 The subject-matter of the book has been gathered from probably the 
 broadest experience ever enjoyed or earned by any man in this country. It 
 was commenced at a time when but very few people knew anything of the 
 Indicator, and the instrument was in a crude state, when it was far from 
 perfect. The hobbies and vagaries of engine builders, the ignorance, preju- 
 dice, and love of the dollar on the part of the steam users, and the bigotry and 
 prejudice of the working engineer, made it at times almost impossible, even 
 when we were investigating for our own benefit, to obtain access to an engine. 
 
PREFACE. v 
 
 But gradually questions arose which compelled some arbitration ; we were 
 fortunate enough to be appointed by the Supreme Court of several States to 
 carry on investigations, which opened up such questions that the steam user 
 and the engine builders were obliged to make a limited use of. the Indi- 
 cator. Meantime the change in engineering has called for a broader use of 
 the Indicator, has called for more knowledge, and that this knowledge shall 
 be based upon fact. The makers of the instrument have kept pace with the 
 requirements of the engineering profession, and, without doubt, the Ameri- 
 can Indicators of to-day surpass everything made in the world before, for 
 their accuracy, and their durability under all the range of requirements 
 from the slow moving low pressure engine, to the high speed and high 
 pressure locomotive, and electric light engine. 
 
 The lessons in this book are drawn from actual practice ; with very few 
 exceptions the diagrams were all taken by our own hands. What this labor 
 has cost, no one but ourself can properly understand. At times working all 
 night, and not in the pleasantest quarters sometimes without anything 
 beyond the crudest tools in attempting adjustment where the builder of the 
 engine had absolutely precluded any adjustment ; working against all the 
 different degrees of prejudice and ignorance, frequently going without food 
 for many hours together, being compelled in a certain time to accomplish all 
 that could be done ; making long railroad rides at night ; working all day 
 and night all this has not been pleasant, but it has brought about, to a 
 great extent, a revolution in the practice of the Indicator, and an amount 
 of information of easier access to the reader. 
 
 These pages are offered with a full knowledge of their faults, but it has 
 been the author's intention to convey knowledge to the greatest extent pos- 
 sible, and in such a way that the working engineer, and the men who use 
 engines,shall understand them and be able to work out their own adjustment, 
 if they will but give a little time and patience to it. The second volume will 
 contain more extended information with reference to the theory of working 
 steam, and the application of general rules as to the measurement of steam 
 and water, with some curious illustrations from actual practice, of the vaious 
 ways of connecting the Indicator to the cylinder, errors in motions, and a 
 variety of matter which is not yet fully laid out. Inquiry has at this time 
 taken a turn toward adding something in reference to combustion and 
 various boiler settings, and, if we follow the subject, it will probably run 
 into the third volume. The second volume will be issued sometime within 
 a year, and, as to the third volume, much will depend upon our personal 
 arrangements, how much can be done, and how much time we can give to it. 
 
 The diagrams in this work are, in in every case, full size, so they can be 
 measured and worked from accurately, or a tracing can be made for that 
 purpose. In every case our aim has been to give the facts, and wherever the 
 name of the builder has been mentioned, it is not with any intention of either 
 
vi PREFACE. 
 
 recommending or disparaging his or their work. The names are used only as 
 the types, and in many cases where bad adjustment has been shown, it has not 
 been any fault of the builder. In other cases this cannot be said. The book 
 is from a practical experience, with all the ins and outs that are liable to occur 
 in a large practice. We only regret that other duties absolutely forbid our 
 giving practical attention and time to the calls which are now made upon us, 
 otherwise we might soon issue a second volume, which, while not containing 
 so much in breadth or in fact, could be made more elaborate, and perhaps 
 more practical and interesting. 
 
 THOMAS PRAY, JR. 
 Boston, January 3, 1883. 
 
 Since the publication of Vol. I. [first edition] all interest in the 
 publication and the copyright have been legally transferred to me. 
 
 THOMAS PRAY, JR. 
 
 July, 1887. 
 
PBEFACE TO VOL. II. 
 
 As announced in Vol. I, this book, Vol. II, is launched, not as a literary 
 effort or a scientific essay, but rather as a practical hand-book or text-book for 
 the working engineer, the steam user or any who may be learning something 
 as to the construction of engines and what constitutes the economy of an 
 engine, what use is made of the steam after being produced by the boiler, 
 and whether this use is good, bad or indifferent. The book has not a single 
 mathematical formula, algebra and the higher mathematics having been 
 entirely left out ; not because the engineers could not understand them, for 
 many of them are capable of understanding the higher mathematics, as we 
 know, and very many make regular use of formulae in their calculations for 
 the sake of brevity. We have ourselves had no difficulty in expressing any- 
 thing in few words without resort to formulae ; and as so many of our engi- 
 neers have graduated from the fire room, and then taken positions in the 
 engine room, or in charge of both, who have had no chance at even common- 
 school education, we have preferred to put everything in the plainest word- 
 ing, so that all might thoroughly comprehend and avoid any confusion or 
 misunderstanding. So much for the general character of the work. 
 
 This work has been compiled from one of the most extensive practices 
 any man was ever engaged in, at a time, too, when the author has been not 
 only busy but a very busy man. Much of the work has been done " atween 
 times," or when, for his own comfort, he might have been resting, and all the 
 time during the progress of the work, which has been slow, and interrupted 
 twice for several months, he has been busy with a large consultation practice, 
 with the cares of a paper, and other matters, so that Vol. II has been delayed 
 many months longer than was expected. 
 
 The subject matter of Vol. II is very largely new, only a few articles 
 having been reproduced from the columns of the Manufacturers' Gazette, 
 and in every case these reproductions have been made use of from radical 
 points either of misuse, misconstruction, or some other peculiarities which, 
 while all too frequent, we are not always able to lay our hands upon for 
 ready reference. The various uses of steam cover a broad ground, from 
 the last new ocean steamship to the 15 horse-power high-speed motor for 
 electricity. All through the work the author has endeavored to avoid any 
 personal reference, or to revive any criticisms other than so far as principles 
 of mechanism, or a wasteful use of steam were concerned. Trials of engines 
 have been for the information of the reader ; trials of indicators have been to 
 obtain absolute information for our own use, and in these cases all have been 
 judged by the inflexible standard of right, without regard to the assertions 
 of the several builders, patentees, improvers or venders, meaning to place on 
 
viii PREFACE. 
 
 record only those facts which were of importance in the use of thia much- 
 abused, much-misunderstood, and yet so simple and accurate an instrument 
 as the steam-engine indicator. A large majority of the diagrams in this vol- 
 ume have been taken by the author's instruments and hands. It has been 
 the aim to avoid repetition and to introduce, as much as was possible, all the 
 conditions of adjustment, whether right or wrong, of construction or of fancy 
 that might possibly arise upon any engines, anywhere, in any kind of service, 
 so that the book might become more valuable to those who were far away 
 from the builders of engines, and to make it all the more valuable to them 
 as affording away out of any trouble into which they might be thrown. 
 
 The extremely .extended use of the steam-engine indicator within the 
 last four or five years, has called for some book from a practical man, which 
 should not in any case toady to the indicator builders, except to apply their 
 instrument when it was reliable, and would record in such a manner that the 
 diagrams were of some practical value to the men who are not thoroughly up 
 in a wide practice. It has also been the aim of the author to be all the more 
 guarded in offering instruction which should be of benefit to the only men 
 for whom we are writing in general, viz., the party who owns the engine and 
 the working engineer in charge of it, so that these two men should be entirely 
 free from the assumption so frequently imposed upon them by ignorant and 
 impractical men who assume the role of experts, never having run an engine 
 a day in their lives. 
 
 Every diagram which is presented is engraved as nearly as it is possible 
 with all the variations which the original contained, in other words, our aim 
 has been not to discriminate in favor of or against any engine builder's work, 
 but to produce actual fac-similes in size, in good or bad points, precisely as 
 the originals were when taken from the engine. The full intention expressed 
 with reference to the second volume has not been realized. The only point, 
 however, is that treating upon the errors of different motions, which is in 
 itself an exceedingly wide range of subjects, and requires a great deal of prep- 
 aration as well as careful experiment. The results of incorrect motions are 
 shown in several instances, and how to obtain correct diagrams is also in sev- 
 eral instances carefully explained. 
 
 As referred to in the first volume, it is not improbable that the thkd 
 volume will follow the second, during the latter part of 1885, in which a 
 careful analysis of motions, the result of errors in motion, and any new 
 features with reference to indicators, or possibly with reference to errors 
 in the different indicators will also be fully illustrated. Much of this work 
 has now been done. Careful study of these motions has been made, 
 experiments are completed, but Vol. II has grown so rapidly, by including in 
 it some of the largest marine powers, that before we would have wished it, our 
 printer has said that we have already exceeded the limit, and the book is, 
 therefore, somewhat larger than at first promised. 
 
 The aim in Vol. II has been to meet the latest practice in such a way 
 that the w r orking engineer should receive from it practical instruction, and 
 if that end is answered, then the real object of the book is consummated. 
 
PREFACE. ix 
 
 Vol. Ill will undoubtedly follow before the New Year, 1886, and will 
 illustrate different reducing motions, and methods of giving motion to 
 the Indicator. 
 
 The labor embodied in a volume of this kind, and especially of Vol. II, 
 cannot be estimated by any one, except its author. It has cost thousands 
 of miles of travel, any amount of personal or physical inconvenience, in order 
 to obta the information which is set forth, and the book, as presented, 
 shows the latest practice in American high-pressure, high-pressure condens- 
 ing and compound of the latest steamers launched for ocean service, as well 
 as the steam- jacketed high-pressure engines. 
 
 The tables in the book have been so arranged for reference as to embody 
 some new principles, and the table of areas in Vol. I having been found 
 faulty, that in Vol. II has been largely computed, and any errors which were 
 found were corrected before its being issued. 
 
 With the wish that the book may answer the purpose of a ready and re- 
 liable reference to the steam-power owner, or others interested, especially 
 those men in charge, we send it on its way, realizing fully that it contains 
 some faults, and without doubt many omissions, but we hope also that it 
 contains much which is valuable, and that the favor with which Vol. I was 
 received may be extended to Vol. II, and it is a curious fact, up to the time 
 of this writing, that many employers have ordered Vol. II for their engineers, 
 while in the case of Vol. I, the engineers ordered it for themselves. Evi- 
 dently the employers have found that the efforts of the engineer towards 
 self-education and a promotion, were for their interest, and we welcome this 
 as a sign of encouragement, especially to the stationary engineers, to con- 
 tinue to improve themselves, which, we know they are doing, in many 
 instances when they can ill-afford the expense. " Knowledge is power," and 
 a stationary engineer can control his power with knowledge, to his own 
 benefit, far better than by lack of knowledge, as so many have already found. 
 The author will be thankful to any of the readers of this work, who will 
 point out any error or who will suggest important points of practical use to 
 be covered in Vol. Ill, 
 
 THOMAS PEAY, JR. 
 
 NEW YORK, January 1, 1886. 
 
PREFACE OF 1909. 
 
 The appliances for the use of the Indicator have multiplied in number, but 
 like too many other such matters, they are many of them of infinitely small 
 practical use, and so the real status of the Indicator is little changed in its 
 useful sense, and so after almost looking for the replacing of u Twenty 
 Years " ^72 th some later book, it is a great pleasure to the author to write 
 down a verification of the good judgment of the owners of the nearly eighteen 
 thousand copies which have found their way to the engineers in all of the 
 countries of the earth where steam power is used. 
 
 In the year 1906, up to October 4th, on which this little addition is written 
 for the printer, over eleven hundred copies have been sent out, letters from 
 India, Alaska, New Zealand, Sandwich Islands, China, Siberia, Russia, 
 Greece, Egypt, Persia, Japan, Mexico, and Brazil, and others are received; 
 some of them have been clients for years, and in the fleets of ships, many of 
 the owners have furnished their men with copies. 
 
 The real progress in the economy of using steam comes only from a correct 
 use, and this from proper knowledge, and this broadens more and more each 
 year. 
 
 This is all the more true for the simple reason that the action of steam 
 under pressure varies but very little, so far as our knowledge of it goes ; men 
 have made seemingly different applications, to engines, turbines, and other 
 methods, but the action of steam is just as it was when Regnault and Rankine 
 worked out so much of the facts as made it easy for the man who " reads as 
 he runs" to apply with the utmost attainable economy. 
 
 It is always a pleasure to receive letters telling of troubles and how 
 they were overcome. Much that is valuable, and which in another book 
 will be very interesting, has in this way come to hand ; it is being put into 
 shape, and it will as it now looks, reach the printer later on, for new readers. 
 
 The gas engine has in some ways proved unable to make a " revolution" 
 as was expected, and to replace steam ; there are many places where its use 
 has succeeded, but it has like the turbine, been found wanting in the broad 
 application that steam fully and successfully covers, completely. 
 
 Thanking each and all for their courtesy and approbation, and wishing for 
 each the full measure of personal success and reward, and that it may long 
 continue, and we may all become more and more competent to deal with the 
 problems to which many have given the largest number of the years of our 
 lives, I send this edition on its way with only kindly wishes to all and every 
 one of its readers. THOMAS PRAY, JR. 
 
 All Interests in the Publication and Copyrights have been legally transferred tg 
 the American Steam Gauge and Valve Mfg. Co., September, 1908. 
 
INDEX. 
 
 FAOl 
 
 Introduction 1-4 
 
 The Thompson Indicator ; How to Attach it ; What to Use ... 4 
 How to Adjust the Tension of the Paper Barrel Spring .... 4 
 
 Applying the Pencil to the Paper ; How to do it Right . . . . 4, 5 
 
 Getting the Diagram in the Center of the Paper ; Things to Avoid . 5 
 How and Where to Attach the Indicator ....... 5 
 
 Clearance or Clear-way ; Size of Pipe ; Be Sure of a Clear Hole . . 5 
 Side-pipe and Three-way Cock Worthless ...... 6 
 
 Reasons Why ; Some Facts in Connection ; Avoid Elbows and Valves ; 
 
 Caution ............ 6 
 
 How to Make the Pencil Lead do Good Work ; How to Sharpen . . 7 
 Blowing out Connection Pipes ; Adjusting the Indicator Pipes ; Oil to 
 be Used ; Balance the Paper Cylinder ; Do not Work with Dirty 
 Hands ; How the Paper Should Fit ; Heating the Instrument ; 
 Caution About Taking the Atmospheric Line, and Why ; Take the 
 Diagram First, Atmospheric Line Afterwards ; Caution About Shut- 
 ting the Cock Closely ; Making Record of Data at the Time of 
 
 Taking 7 
 
 The Steam which the Spring Will Take 8 
 
 A Suggestion ; Washers for the Indicator Piston ; Things to Look Out 
 for so as to Avoid Trouble; The Kind of Oil, and Why; Which 
 Spring to Use ; Why the Small Diagrams are Not Correct . . 8 
 Changing the Spring ; How to do it Correctly . . . . .9 
 Hints in Connection with Changing ; General Hints .... 9 
 The Thompson Improved Indicator with Detent Motion . . . .10 
 
 Swivel Pulley for Conveying the Motion 10 
 
 Methods of Attaching the Indicator or Making the Reducing Motion . 11 
 Some Faults of the Pendulum Motion ; Cautions in its Use ; How to 
 
 Get the Best Motion from a Pendulum ...... 11 
 
 Bacon's Attachments for Pendulum or Pantograph; How to Use Them 12, 13 
 How to Set the Pantograph Motion . . . . . . . .13 
 
 Working by Right Angles ; Caution ....... 13 
 
 Pantograph on Horizontal Cross-head . . . . .14 
 
 Pantograph and How to Apply it Accurately . . . 14, 15 
 
 Sliding Loop; A New Thing . -, . . . . . , . 15 
 
 Computing the Indicator Diagram . . . .... 16 
 
 Different Methods ; Caution as to the Correctness of Data ; Working up 
 the Diagram ; The Unit of Horse-power ; The Process of Comput- 
 ing ; Obsolete Methods Mentioned . . . . . . . 16 
 
 Polar Planimeter . .17 
 
in INDEX. 
 
 PASS 
 
 The Process of the Computation of the Diagram by Means of the Plan- 
 
 imeter Explained ; How to Use the Planimeter Correctly . 17, 18 
 Measuring Diagrams with Loops ; Negative Quantities . . 19 
 
 Ascertaining the Power from the Planimeter Reading ; How to Reduce 
 Area to Mean Pressure ; The Mean Pressure to Horse-Power ; An 
 Instance ; How to Test the Planimeter for Correctness . . 20 
 Different Factors in the Diagram . .- . . . . . 20 
 
 Necessity of Reliable Data . . .... . . . . 21 
 
 Lesson I . 22-26 
 
 Bacon's Method of the Theoretical Carve by Ordinates, with an Analysis of the Various Lines 
 of the Instrument. 
 
 Lesson H . . 26-30 
 
 The Theoretical Curve Applied to a Corliss Engine The Same Application Made to a Steam- 
 ship Engine, with Directions to the Student as to all the various Lines and Terms. 
 
 Lesson in V. . . . 30-33 
 
 Typical Diagrams. 
 
 Lesson IV . 33-35 
 
 A Wheelock Engine The Practical Application of the Indicator An Engineer who didn't 
 Believe in the Indicator How this Diagram was Corrected Waste. 
 
 Lesson V . ........ 35-38 
 
 Two Interesting Subjects Locomotive Practice on a Stationary Engine Tardy Admission- 
 Steam Wire Drawn A Two Hundred Horse Engine Doing Three Hundred and Eighty 
 Horse-PowerLack of Economy. 
 
 Lesson VI 38-40 
 
 A High Speed Engine with Several Kinks. 
 
 jLesson VII . . . . . . . . . 40-46 
 
 Harris-Corliss Engine An Engineer Learning the Practical Lack of Reliance Upon the 
 Three- Way Cock System of Taking Diagrams Curious Diagrams Fluctuations of the 
 Regulator, and the Reason For It The Actual and the Mean Both Ends Should Do the 
 Same Amount of Work The Rollins Engine with Very Light and Very Heavy Load- 
 Something About Compression. 
 
 Lessons VIII-IX 4&-49 
 
 Simultaneous Diagrams Their Value in Adjustment and Indicating Corliss Engine by a 
 Man who Used Indicators The Amount of Theoretical Utilized Two and Two- 
 Thirds Pounds of Coal per Hour. 
 
 Lesson X .... - 50-52 
 
 Buckeye Engine Loss of Boiler Pressure Back Pressure Loops. 
 
 Lesson XI . . .... . -,..-: 52-55 
 
 Corliss Engine Built for the City of Boston Pump High Pressure and Low Pressure 
 Diagrams Coal per Horse-PowerBoiler Pressure Utilized Its Performance After 
 Put at Work for the City of Providence. 
 
 Lesson XII .. . . ., 55-58 
 
 The Corliss Pawtucket Pumping Engine High and Low Pressure Diagrams Dimensions- 
 Duty. 
 
 Lesson Xin . . . . . . . . ;. . 58-61 
 
 Corliss Engine A Curious Fault Found by the Indicator Indicator at Fault Another 
 Curious Case StiU Another Trouble in the Indicator Trouble in the Indicator 
 Cylinder. 
 
 Lesson XIV . 61-63 
 
 A Brown Engine in Bad Condition Queer Looking Diagram Misuse of Steam Setting an 
 Engine by Marks or by the Indicator Indicator out of Order. 
 
 Lesson XV . . . . . . . 63-66 
 
 Harris-Corliss Engine Another Case of Setting Valves by Marks A Disgusted Engineer- 
 Queer Diagrams The Indicator and its Results. 
 
INDEX. xiii 
 
 MOB 
 
 Lesson XVI .... 66-69 
 
 Buckeye Engine One Indicator and a Three-Way Cook Deficiency in Realized Boiler 
 Pressure A Contrast Harris-Corliss Engine Realization of Boiler Pressure Indi- 
 cator Attached by Three-Way Cock. 
 
 Lesson XVII ....... . 69-71 
 
 Greene Engine Queer Practice Loops and Late Steam A Curiosity. 
 
 Lesson XVIH .... . 71-75 
 
 Saw-Mill Diagram Large Back Pressure Lack of Economy Radically Bad Diagrams- 
 Curious Figures Something to Study Two of the Worst Possible Misuses of Steam. 
 
 Lesson XIX , 75-80 
 
 The Results of a Visit How Some Men Run Corliss Engines A Hard Working Engine- 
 Lesson in Natural History What an Hour's Work Did $12 a Day Saved How the 
 Valves Were Changed to Accomplish the Result Careful Analysis of all the Changes- 
 Two Thousand a Year. 
 
 Lesson XX 80-82 
 
 The Hyperbolic Curve A Simple and Correct Way of Laying it Out, with Full Instructions 
 How to Do It. 
 
 Lesson XXI . 82-84 
 
 Another Method of Laying Out the Hyperbolic Curve, with Full Directions How to Do It 
 The Rollins Engine Elegant Card. 
 
 Lesson XXII . 84-87 
 
 An Experiment Late Lines Mai- Ad justment of Valves Peculiarities of Practice Small 
 Pipes Bad Work. 
 
 Lesson XXIII . . 87-89 
 
 An Expensive Engine to Run A Bad Diagram An Instructive Lesson Lack of Vacuum 
 and Boiler Pressure Insufficient Steam Passages Wire-Drawn Steam A Wright 
 Engine Thirteen Years Old A Comparison. 
 
 Lesson XXIV 90-92 
 
 Corliss Engine Thirty Years Old An Economical Result An English Engine in Comparison 
 Some Interesting Features. 
 
 Lesson XXV .... ... 92-94 
 
 A Search After Information What Occurred Queer Looking Diagrams Late All Round- 
 Bad Practice A Radical Improvement. 
 
 Lesson XXVI 94-100 
 
 The Planimeter Applied to the Computation of Indicator Diagrams, with Full and Explicit 
 Directions What to Do, What Not to Do, and How to Do It Which Way to Run the 
 Flanimeter Where to Commence How to Prove Your Reading How to Measure 
 Loops or Expansion Below the Atmospheric Line, and Much Other Valuable Informa- 
 tion with Regard to the Use of this Instrument. 
 
 See also pp. 17 to 20. 
 Lesson XXVII 100-102 
 
 An Old Style Corliss Engine One That Had Been Abused What an Intelligent Engineer 
 Accomplished A Contrast Old-Fashioned Slide Valve Wire Drawn. 
 
 Lesson XXVIII . . . 103-105 
 
 One of the Most Important Lessons for Beginners What Will Sometimes Happen in Actual 
 Practice How a Man Discovered His Own Unreliability Some Curious Looking Marks 
 on a Diagram What Not To Do. 
 
 Lesson XXIX . 106-109 
 
 Curiosities of Steam Practice Thick-Headed Steam Users Heating by Back Pressure Car- 
 ried to Excess. 
 
 Lesson XXX . 109^111 
 
 The Hartford Engineering Company's Engine Good Steam Lines The Reynolds-Corliss 
 Engine A Contrast in Engineering Experience. 
 
 Lesson XXXI ... 111-114 
 
 Indicating an Engine by Telegraph A Positive Fact Queer Looking Lines The Results of 
 a Careful Examination Tool Chest in a Steam Chest The Result of Careful and 
 Searching Investigation A Converted Engineer Practical Jokes and a Curious Finale. 
 
xiv INDEX. 
 
 PAGE 
 
 LessoD XXXII ,~. . . . .... . . 115-118 
 
 An Engineer Without an Indicator A Harris-Corliss Engine in Bad Condition Ignorance 
 and Avarice What a Few Hours' Work Accomplished And What a Saving was Made 
 by an Adjustment of the Valves. 
 
 Lesson XXXHI . . 119, 120 
 
 Reynolds-Corliss Running by High Pressure and a Sensible Engineer. 
 
 Lesson XXXIV . . . . ... . .... 120-123 
 
 The Misuse of Steam, or Natural History by the Indicator Something For Beginners to 
 Study Closely How to Make the Corrections to Accomplish Readjustment. 
 
 Lesson XXXV . . . 123, 125 
 
 Curiosity in Steam Practice from an English Engineer High Water Consumption Very 
 Peculiar Diagrams One End of an Engine Doing More Than All the Work One 
 Engine of a Pair Stopped, and Less Fuel Used. 
 
 Lesson XXXVI . ........ 126, 127 
 
 Wheelock Engine Doing All the Work on One End Peculiarly Poor Diagrams A Lesson 
 for Study. 
 
 Lesson XXXVII . . 128-130 
 
 A High Speed Engine With Peculiar Results The Difference Between Boiler Pressure and 
 Realized Pressure, and the Percentage as Between Two Ways of Working Steam An 
 Interesting Study. 
 
 Lesson XXXVIII . . 130-132 
 
 A Brown Engine A Very Fine Diagram An Interesting Subject. 
 
 Lesson XXXIX 132-134 
 
 The Difference Between Representation and Actual Performance A Corliss Engine Put to 
 the Theoretical Test. 
 
 Lesson XL 135-137 
 
 The Latest Departure in High Speed, the Armington & Sims Engine A Very Interesting 
 Subject An Experiment with Very Gratifying Results Something for Engineers or 
 Beginners to Study Close of the Practical Lessons. 
 
 Lesson XLI 138-143 
 
 Demonstrating the Actual Point of Cut-off from Steam Used when the Lines are Indistinct 
 and the Terminal Pressure Not Made Use of Reasons for Discarding Old Theories- 
 Example Diagram from Leaky Valves Proof of its Correctness Full Directions for 
 Making the Demonstration. 
 
 Lesson XLII 143-146 
 
 Demonstration of the Point of Cut-off and How to Lay Out the Theoretical Curve Full Ex- 
 planations for the Combination of these Two Distinct Propositions. 
 
 Lesson XLIII 146, 147 
 
 Application of the Previous Demonstration to a Sound Steamer. 
 
 Lesson XLIV . . . . . . . . . . 148-152 
 
 A Modern Steamship Engine Examined for the Determination of Several Points, among 
 which are Two Different Indicators- Interesting Result How Compound Engines 
 Work. 
 
 Lesson XLV ... . . . . . . . 152-154 
 
 A Badly Throttled Engine, Great Loss in Boiler Pressure and in Valves. 
 
 Lesson XLVI ... ."'"..'. . . . . . 154-156 
 
 High Speed Diagram Trial of the Indicator What Makes Fluctuations in the Cylinder. 
 
 Lesson XLVH . . . . . . . . . . 156-158 
 
 Medium High Speed Engine, Large Load Application of the Demonstration Clearance 
 Unimportant. 
 
 Lesson XL VIII .... . . 159-161 
 
 An Expensive Use of Steam Actual Fact and Possibility Comparison Which Shows What 
 Might Be if the Mechanical Construction was Right. 
 
 Lesson XLIX , . 161-165 
 
 A High Speed Engine Speeded Up to Try the Thompson Improved Indicator, 435 a Minute 
 The Application of Both Demonstrations and the Clearance Added What Makes the 
 Wavy Line of Expansion Exhausting 33 Pounds Above the Atmosphere. 
 
INDEX. xv 
 
 PAGE 
 
 Lesson L 165-167 
 
 Carrying Steam Full Stroke and Exhausting Under Excessive Back Pressure Lack of 
 Realized Pressure Late Admission A Comparison for Results. 
 
 Lesson LI 167,168 
 
 Harris-Corliss Engine Diagram Distorted by Incorrect Motion. 
 
 Lesson LIT 168-170 
 
 A Curiosity in Diagrams. 
 
 Lesson LIII 170,171 
 
 Adjusting Corliss Engine Valves, the Changes Made and the Reason Why Illustrated. 
 
 Lesson LIV 172-174 
 
 Expensive Cut-off by Cheap Attachments. 
 
 Lesson LV . . . .... 174-176 
 
 Corliss Compound, High Duty Pumping Engine The Highest Realized Efficiency Cost of 
 Running from Official Figures Duty and Some Other Interesting Facts. 
 
 Lesson LVI .... . ... 177-179 
 
 Short Connections on an Engine Which Had Been Adjusted for a Three-way Cock and Side- 
 pipe Contrast Excessive Compression. 
 
 Lesson LVII ... 179,180 
 
 Three-way Cock and Side-Pipe on Same Engine as the Preceding Lesson Compare the 
 Two Sets of Diagrams. 
 
 Lesson LVIII '. . . 181-183 
 
 High Cost, Low Economy Steam Yacht Compound Peculiar Diagrams Low Efficiency. 
 
 Lesson LIX 183-186 
 
 An Ocean Steamship Compound Peculiar Diagrams and Curious Results Lack of 
 Efficiency. 
 
 Lesson LX . 186, 187 
 
 An Experiment by an Engine Builder A Poor Imitation of a Good Engine. 
 
 Lesson LXI .... .... 188-190 
 
 Difference of Realized Pressure in the Cylinder at Different Speeds A Lesson on Feed- 
 pipes. 
 
 Lesson LXII . .190,191 
 
 Another Lesson on Feed-pipes A High-speed Engine in Comparison with Previous 
 Lessons. 
 
 Lesson LXIII . . . . , . - . . . 192,193 
 
 Sound Steamer with Large Cylinder as Compared with Previous Marine Engines. 
 
 Lesson LXIV 193-195 
 
 Large Low-pressure Engine on Sound Steamer 4,500 H. P. in a Single Cylinder. 
 
 Lesson LXV 196,197 
 
 An Overloaded Engine, 46 Pounds Terminal Above the Atmosphere. 
 
 Lesson LXVI . . ... 197, 198 
 
 Harris-Corliss Engine Doing Double Work. 
 
 Lesson LXVII .... . . 198-202 
 
 The Latest Triple Compound Ocean Steamship Engine Something to Study A 13,000 H. P. 
 Machine Somewhat Curious Results Some Lessons Lack in Realized Pressure as 
 well as of Yalves Handling the Steam. 
 
 Lesson LXVIII ... .... 202-205 
 
 German Built Corliss Compound, but Without the Corliss Valve-gear. 
 
 Lesson LXIX 205, 206 
 
 Mistake in Indicator Motion and Curious Result How to Use the Planimeter on Such a 
 Diagram. 
 
 Lesson LXX 207-SU 
 
 Defects Shown by the Indicator Comparisons A New Engine Leaking Badly How This 
 Occurred and the Reasons An Experiment by a Builder Lack in Realized Pressure, 
 no Expansion, Trouble in the Exhaust Corliss Steam Jacketed Showing a Strange 
 Contrast to the Other Diagrams in the Same Lesson. 
 
xvi INDEX. 
 
 PAGK 
 
 Lesson LXXI .... 211-217 
 
 An Experiment with Different Indicators on the Same End of the Same Cylinder, at the 
 Same Time Very Curious Looking Cards Queer Expansion Lines Change of Pres- 
 sure, Volume, Temperature Friction and Loaded Cards Together Something About 
 the Change of Speed in the Crank Engine Running 276. 
 
 Lesson LXXII 217-221 
 
 Extreme High Speed, 500 to 640 Revolutions The Thompson No. 2 Indicator, or Small 
 Paper Cylinder Diagrams at 536 Revolutions per Minute 562 Revolutions Queer 
 Expansion Lines and Queerer Compression Difference Between Different Indicators 
 at the Same Instant 562 Revolutions 642 Revolutions Where the Indicators 
 Stopped to Rest Deductions. 
 
 Lesson LXXIII 221-224 
 
 American Compound on River Steamer Lack in Realized Pressure Falling df in the 
 Compound Cylinder Curious Expansion Line, Badly Wire-drawn Lack of Realiza- 
 tion in Volume A Most Interesting Lesson What Could be Done if the Pressure in 
 Both Cylinders Were Utilized A Wide Difference Between Actual and Theoretical. 
 
 Lesson LXXVI . 225-227 
 
 A Compound Non-Condensing, or Compound Hish Pressure Engine Very Curious Dia- 
 gramsAn Erratic Governor Lack of Realized Pressure An Attempt to Run the 
 Compound Cylinder High Pressure, a Curious Result The Compound Cylinder 
 Working as designed Very Erratic Diagram Eight Pounds of Fuel per Horse-Power 
 an Hour. 
 
 Lesson LXXV 227, 228 
 
 Fishkill Landing Corliss Engine A Diagram Taken from Every-day Work to Ascertain 
 What Was Being Done Handsome Lines No Necessity for Clearance When Work- 
 ing for Expansion. 
 
 Lesson LXXVI . . 229-232 
 
 An Ocean Steamship Compound Fitted with Corliss Valves. 
 
 Lesson LXXVII 232-235 
 
 An Ocean Steamship Compound A Considerable Difference Caused by Unequal Side-pipe 
 Attachments. 
 
 Lesson LXXVIH . . . . . . . . . 235, 236 
 
 Condensing Beyond Economy. 
 
 Lesson LXXIX 237,238 
 
 An Old Corliss Engine Its Economy Cost of Horse-Power per Hour Authentic Data. 
 
 Lesson LXXX 239-241 
 
 An Overloaded Corliss Engine Defects of General Arrangement in Feed-pipe Difference 
 in the Ends in Amount of Work Necessity of Simultaneous Diagrams for Adjustment 
 or Power An Interesting Lesson. 
 
 Lesson LXXXI . 241-244 
 
 An Ocean Compound Some Curious Results. 
 
 Lesson LXXXII . . V . . - 244-24S 
 
 Defective Construction An Engine Which Leaked, Raced, Piston Covered the Indicator 
 Hole A Combination of Defects An Incident in the Use of the Pantograph A 
 Curious Expansion Line A Curiosity Experimental Steam Engine Building. 
 
 Lesson LXXXIII 249-258 
 
 For the Beginners What an Indicator is For The Ideal or Perfect Diagram Difference of 
 Release and Compression Excessive Steam Lead, or Compression General Defects 
 Which Are to be Looked For Circumstances Which Influence the Different Lines- 
 Change of Release and Compression Cushion, What it Accomplishes Variations 
 from the Ideal Diagram Some Examples and What Caused Them Wire-drawing 
 Late Release- Imperfect Vacuum Throttling -Quickening the Time of Valves Late 
 Admission Rolling the Eccentric Forward Obtaining Both Points by One Movement 
 How to Adjust These Matters on Different Engines Prick-Punch Marks, Cold 
 Chisel Slashes not to be Noticed or Relied on Steam Chest Diagrams, What They 
 Are For, Their Importance and Value Other Places to Attach the Indicator- Caution 
 as to Condensing Engine Attachments Suggestions The Diameter of a Piston-rod 
 Out of the Crank End of the Engine. 
 
 Lesson LXXXIV . . ;. ... . . 259, 26(] 
 
 Water per Horse-Power from the Diagram, or Steam Consumed -Full Directions for the 
 Computation. 
 
INDEX. 
 
 xvii 
 
 PAGK 
 
 Another Method of Computing the Water per Horse-Power per Hour . 261 
 
 Vacuum 261, 262 
 
 Temperature of the Vacuum at Different "Pounds per Square Inch" 
 
 and " Inches of Mercury." ........ 261 
 
 Total Heat ... . . . . . . . . .261 
 
 Inches of Mercury, Expansion of Mercury ...... 262 
 
 The Density of Steam . . 262 
 
 Temperature of Vacuum . . . . . . . . 262,263 
 
 An Improved Draft Gauge for Chimneys. 264-268 
 
 How to Test Feed-water for Boilers Testing Feed-water Heater Test- 
 ing Thermometers .......... 269 
 
 Lusterless Finish on Tempered Steel . 271 
 
 Patent Varnish .... 271 
 
 Calorimeter Test 272 
 
 Iron Paint . . . . .' . . . . .. . . 273 
 
 Joule's Equivalent . ... . . 273 
 
 Coloring Soft Solder Yellow 274 
 
 Recipes for Soldering Fluid -7 . . . 275 
 
 SAFETY-VALVE PROBLEMS To Find the Pressure of the Ball as it Hangs . 275 
 To Obtain a Certain Pressure with the Ball . . . . . . 275 
 
 To Obtain a Ball for a Certain Pressure . 276 
 
 To Ascertain the Proper Size of the Safety Valve for Any Given Grate 
 
 Surface ....-.." 276 
 
 Restoring Tarnished Gold . 276 
 
 Water in the Cylinder . 277 
 
 To Cut Gauge Glasses to Any Length 277 
 
 Babbitt Metal, Different Formulae . ' . . . ' . . . . .278 
 
 Useful Numbers for Rapid Approximation ^ .... 279 
 
 The Properties of Saturated Steam . . ... . . . . 280 
 
 Table I. Properties of Saturated Steam, 1 to 200 Ibs. . . . .281 
 
 " II. Areas of Circles from J" to 90" Diameter . . . .282 
 
 " III. Hyperbolic Logarithms . 283 
 
 '-' IV. Effect of Expansion with Equal Volumes of Steam . . 283 
 w V, Fractions of an Inch in Decimals . 284 
 
YEARS WITH THE INDICATOR. 
 
 College, New Haven) came into our hands, that we commenced, in the latter 
 part of 1865, to adjust the valves of steam engines by the use of the 
 indicator. If we had only been as careful then in keeping our memoranda as 
 we are to-day, we could produce some facts with reference to some of the best 
 steam engine builders in the country that would open the eyes of our readers 
 wide with astonishment. In fact, it is a matter that is known to some people 
 still living that we had a long, almost hand-to-hand fight. The indicator was 
 denounced, and the man who had the presumption to attempt to get away 
 from the old prick-punch marks and cold chisel dents on main shaft, 
 eccentrics, straps, valves and connections, was denounced as strongly as the 
 English language was capable of. In fact, invectives were freely used ; but 
 all that has passed away and much credit is due to Mr. Charles B. Richards 
 for his having studied the defects of the old indicator, and by the use of the 
 Richards indicator eliminated many of these defects of the steam engine 
 builders, until finally the very men, who in 1865 were extremely vindictive, 
 because their old ways of working had been declared incorrect, are now the 
 men who make free use of the indicator and who advocate it and advise it. 
 
 This change has been brought about within the twenty years covered by 
 our own practice, terminating with the issue of this Volume II. But the 
 indicator is now of use for more purposes than one. In 1880 we commenced 
 a series of articles in a paper then edited by us, which shortly after grew into 
 a large circulation, and which has done much to awaken working engineers 
 to the fact that by extending their knowledge they could make themselves 
 more valuable and could produce higher economy for their employers. These 
 men, many of them, have not been slow to avail themselves of this knowledge, 
 and in very many cases they have been personally benefited by being promoted 
 to better positions, and there are, no doubt, many others who will be rewarded 
 in the same way ; but it is a work of time. Employers, on the other hand, have 
 been slow, in some cases, to recognize the value of the indicator and its 
 application, and particularly the fact that the engineer who was familiar with 
 it, was worth more money to him or them than one who was ignorant of it. 
 Like all other innovations on ancient practice, the working engineer must be 
 patient and must produce the results, and then no man or class of men are 
 quicker than employers to find the benefit of the change accruing from the 
 proper application of the indicator ; then the men who can handle it with 
 best purpose can certainly receive all that belongs to them. But during the 
 years past employers have a great many times been seriously misled by men 
 who adopted the word "expert" as a prefix or suffix, and who are really 
 incompetent, and they have paid dearly for this experience, so that really the 
 indicator and its advocates must be prepared to outlive this reputation, 
 which is no fault of the indicator, but rather of a class of men who live upon 
 the credence of others. But taking it all in all, the use of the indicator has 
 vastly extended within the last four or five years. 
 
 Following up the improvements which have been made in the steam 
 engine indicator since the author's first connection with it (and during which 
 time he has owned almost every indicator which has been manufactured, to 
 
TWENTY YEARS WITH THE INDICATOR. 3 
 
 any extent at least, and some which never should have been manufactured and 
 are not now), and finally found the instrument which for all purposes has 
 given the most reliable results, including all that is expected of an indica- 
 tor, and that is, the Thompson Improved Indicator, which is the only one 
 illustrated in this volume, and which the author uses exclusively in his own 
 practice on trials for power, on tests for the position of the valves, for the 
 correctness of working steam and for all purposes wherever he is profession- 
 ally called to attend to adjustment, correction, economy, or power tests ; and 
 in connection with this indicator he has used everything which has been 
 found in the market, ancient and modern, up to the issuing of this book, 
 making trials of different speeds, under different conditions, with different 
 pressures, and with different positions of valves, and the trial has in every 
 case re-asserted the correctness of his adoption of the Thompson Improved, 
 and in some cases where very serious errors were found in either one or the 
 other essential requirement or relation of valve, valve action, working of 
 steam, or large variation in the amount of power, under identically the same 
 circumstances. The author desires to state here that he has no connection 
 with any indicator attachment, engine or steam appliance, no interest financi- 
 ally, direct or remote ; and wherever comparisons are used they are used as 
 matters of fact for the information of the reader and with the intention that 
 such information shall be reliable, our sole interest being to make this book 
 more valuable than any that has preceded it. 
 
 The various defects which are found in the old indicators have gradually 
 been removed; some of them have been faults of mechanism, others of 
 mechanical construction, while others have led to a change in mechanism and 
 construction, and in some cases in the proportion of parts and to a decided 
 change in the mechanism adopted to produce the required result. The 
 lessons which follow this are very largely from our own practice. Some 
 curious examples are shown, and in every case diagrams are engraved pre- 
 cisely as they were taken, full size, and can form the basis of comparison or 
 can be figured from, without any reduction of proportion or percentages. It 
 is proposed to introduce everything up to the most recent practice, particu- 
 larly that of some steamships, the diagrams of which have never been printed 
 before. Many of the matters introduced are original, particularly that of 
 demonstrating the cut-off from the actual pressure of steam from some point 
 on the expansion line. Some of the methods of working out diagrams we 
 have never seen in print before, and some of the oldest engineers and best 
 scientific men in the country have carefully gone through the demonstrations 
 and pronounced them mathematically correct. All these demonstrations are 
 put in plain language, without mathematical or algebraic formula, so that 
 everyone can fully understand and work from them without reference to any 
 of the works upon higher mathematics. Volume II. is intended to cover the 
 whole ground, and there is no reference from Volume II. to its predecessor, 
 and no need of reference from one to the other for any purpose of computa- 
 tion. Volume II. will be found to contain a far broader scope than Volume 
 I., and it is intended to be a companion to the working engineer, to answer 
 
4 TWENTY YEARS WITH THE INDICATOR. 
 
 his questions at all times, and to answer them in such a way that whatever 
 may be the situation or position, he can at once adapt himself and his indicator 
 fco the case, with a certainty of correct results. 
 
 THE THOMPSON INDICATOR. HOW TO ATTACH IT, AND WHAT TO USE. 
 
 Figs. A and B represent respectively, A an outside view and B a section. 
 In Fig. A the parallel motion is shown, which is now made of drop-forged, 
 
 compressed steel. The paper barrel is 
 very light, and when taking off the paper 
 barrel, there will be found inside a milled- 
 head, above which is a thumb-screw, shown 
 in Fig. B. The spring of the Improved 
 Thompson is coiled, in Fig. B, into the sec- 
 tion upon which the end of the pencil lever 
 touches ; a sleeve runs down over the 
 spindle, upon which is a hook, and that 
 hook engages with the inner coil of the 
 spring. By loosening the thumb-screw 
 shown in the sectional view B, and grasp- 
 ing firmly the milled-head cover, after the 
 I paper barrel has been removed, we can get 
 any amount of tension required, changing 
 the tension according to the speed of the 
 engine we propose to indicate. In section 
 B, the spring is shown, the inside of the 
 piston barrel, with an universal joint which engages with the lever at the top 
 and below the piston of the instrument, the coils of the spring and con- 
 nection with the steam cylinder all precisely as 
 they are found in the instrument. If we refer 
 again to Fig. A, there are one or two things that 
 need to be noticed. The first is, that the parallel 
 motion of this instrument, while sufficiently 
 strong to withstand all necessary force as employ- 
 ed, must be treated with care ; sometimes the 
 springing of either one of these parts will make 
 radical errors in the diagrams, and they must 
 always be carefully lubricated. When applying 
 the pencil to the paper, we do not use the little 
 bone handle shown in both A and B, as connected 
 with the shank which holds the stand of the par- 
 allel motion, which brings up against the stop! 
 shown between the cylinder of the indicator and 
 the paper barrel in both Figures. A little care 
 right here will save a great deal of trouble, inaccuracy and uncertainty. The 
 end of the pencil lever is split, forming a shank which springs down upon the 
 
 FIG. A. 
 
 FIG. B. 
 
TWENTY YEARS WITH THE INDICATOR. 5 
 
 lead ; after the lead (leads are furnished already made) is pushed into this 
 spring shank and through it a little distance, having been carefully sharpened, 
 then adjust this bone handle by means of the screw and the stop, so that the 
 end of the pencil shall not strike against the paper ; but when we wish to take 
 a diagram, having put the paper on the paper cylinder, turn on steam, then 
 with the thumb and forefinger grasp this bone handle firmly, hold it against 
 the stop, screw it until you feel the action of the pencil on the paper, screw it 
 up again so that the pencil leaves the paper, and if you do it delicately, you will 
 get the finest possible diagram without any danger of injuring or cramping the 
 instrument. Another thing which should always be done : get the diagram as 
 nearly as possible in the center of the paper and lead off the cord from the 
 pulleys shown, as nearly level and at right angles as possible. Don't turn 
 them around. A great deal of distortion comes from not paying attention to 
 the hints embodied in the previous clause ; sometimes parties who cannot 
 afford to be delicate in their manipulation of the indicator, bend the lever by 
 jamming the lead against the paper and springing it perhaps an eighth of an 
 inch or more. That is sure to distort some of the lines and if the pencil lever 
 or the radial bar is sprung, then the instrument must go back for careful 
 overhauling and repair. The radial bar and lever, although made of drop- 
 forged steel, are very small, and while they are strong, they will not do with 
 rough usage, and yet they will withstand an amount of abuse that one might 
 wonder at, after having examined them. 
 
 HOW AND WHERE TO ATTACH THE INDICATOR. 
 
 There is always a clearance in any engine we have ever yet seen. This 
 is a space between the piston, when it is at the extreme range of stroke, and 
 the cylinder head ; this is variously estimated and in different engines varies 
 materially in proportion of percentage to the whole volume of the cylinder. 
 Wherever the indicator is attached there must be a clear way into the clear- 
 ance, so that the piston shall not shut it off, even partially, when at the extent 
 of its stroke. The usual connection is a half-inch gas pipe or steam pipe, and 
 if this is carried out, it is quite large enough ; whenever the engine is indi- 
 cated, make sure, among other things, at the very outset by " turning her 
 over " that no part of the piston travels over the connection into the clear- 
 ance ; if so, one of two things must be done, either drill another hole and 
 this is not always practicable or take a chisel with point so that you can 
 break off the inside, and give fully the area of a half -inch pipe without any 
 possibility of obstruction or reduction. Always endeavor when tapping an 
 engine to tap it so as to use the pantograph, remembering that the panto- 
 graph can be used vertically, so as to make your connections on the top of 
 the cylinder sometimes, or horizontally so as to make them on the side. It 
 is best to make these connections between the ports rather than opposite 
 them, but sometimes there is no choice. Whenever these openings are made, 
 take particular care that the inside end is clear, either with the chisel or rim- 
 mer, else you have a factor of uncertainty. It is a frequent practice with 
 
6 TWENTY YEARS WITH THE INDICATOR. 
 
 many builders of the very late years, to furnish what is called a side-pipe and 
 three-way cock with each engine. The whole thing is to be condemned, un- 
 less an approximation is wanted for the load, for the position of the valves, 
 etc., and if our readers will turn to Lessons LVI, and LYII, Figs. 116 and 
 117, they will have a chance to see the position of the valves as shown by the 
 three-way cock and side-pipe in one case, and the short connections in the 
 other case, nothing having been moved, so far as the valves, eccentrics, etc., 
 were concerned. On marine engines it is very fashionable (for we know no 
 other reason for it) to take an inch and a quarter, or inch and a half pipe, lead 
 it from the clearance at either end to the most convenient part of the cylinder, 
 back of the side-pipes, and there put in the three-way cock. We have seen 
 and used this upon condensing engines with 12 and 14 feet stroke, and* in 
 one case where the steam line figured. 3 inches of the length, by the propor- 
 tion of stroke on the diagram, the engineer had the curiosity as well as good 
 sense to strip his side-pipe ; two days afterwards we applied the indicator 
 with short connections showing that the valves were open at the very com- 
 mencement of the stroke and the steam line did not vary one-half of one inch 
 when the short or proper connection was made, yet in traveling several feet 
 it showed late, for the paper barrel started when the piston started, but the 
 steam traveled from the clearance through the various angles and ports of the 
 cock into the indicator with whatever little condensation took place on the 
 way, so that the motion was distorted 3f inches from the truth ; this makes 
 a difference in the pressure of steam as well, so that it may be laid down as a 
 rule, to avoid three-way connections if the real position of the valves is of any 
 consequence, or if the actual condition of the valves is to be learned from the 
 diagrams. Several instances of side-pipes are shown in this volume, some of 
 these would be very dangerous if the valves were adjusted to bring the steam 
 lines up at right angles to the atmospheric line and still use the side-pipe. It 
 would be apt to result in something quite similar in effect to that shown in 
 Lesson LXIX, Fig. 135. 
 
 It is sometimes impossible to use the short connection, but wherever it 
 can be done, it is decidedly better to do it, if accuracy is any sort of a condi- 
 tion towards which you are aiming for results. Avoid elbows and valves in 
 feed-pipes and exhaust-pipes as much as possible, always remembering one of 
 the fundamental laws of all engineering, viz. : that the shortest possible dis- 
 tance from any given point to another is a straight line, so remember that 
 in handling steam the utmost economy attainable wherever steam is conveyed 
 through pipes, is invariably accomplished by taking the steam as direct as 
 possible and avoiding every impediment or obstruction, such as is offered by 
 globe valves, reducing valves, throttle-valves, elbows, crosses, T's, or other 
 angles, through which steam must pass in order to reach the piston head. 
 Anything which interrupts the flow of steam causes friction, loss of pressure ; 
 and in every case where the pressure of steam is reduced, its volume is in- 
 creased and it takes the first step towards the convemon from steam into 
 water again. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 A POINT AS TO HOW TO MAKE THE LEAD DO GOOD WORK. 
 
 It is much, better to sharpen the lead before being put into the spring 
 shank in the end of the lever, by means either of a scythe-stone or dry oil- 
 stone, or if nothing better is at hand take a fine file. A point which is rubbed 
 up in this way, and made smooth and clean, will last much longer, make a 
 cleaner mark and be much better than one which is whittled or coarsely done. 
 The best way is always the easiest, the surest and the cheapest, all things 
 taken into account. There is no necessity for running over a large number 
 of times. This much for the manipulation of the instrument. 
 
 Having attached the indicator to the side pipes, which must in all cases 
 be blown out thoroughly and completely before applying the indicator, be 
 careful not to employ joints with red lead or white lead or any other material 
 which can possibly interfere with the action of the piston ; then adjust the 
 indicator to the top of the cocks, screw down the variable screw, having first 
 put the indicator as nearly in line with the motion as is possible, make sure 
 that all is fast and then let the steam on to the instrument gently, warm it 
 up, allow all the water to get out so far as possible. While the instrument 
 is working put a drop or two of porpoise oil on to the top of the piston as it 
 comes through the cover of the case; repeat this occasionally. Now, try the 
 motion with the pantograph, pendulum or whatever else may be used, and 
 carefully adjust it for the stop. The paper cylinder must not, on any account, 
 touch either end of the travel against the stop, even so slightly as not to be 
 noticeable, for it will distort some line of the diagram as sure as it does. 
 Having balanced the instrument, as we term it, you are now ready to go 
 ahead. In taking a diagram, don't work with dirty hands ; you are sure to 
 dirty the instrument, and the diagrams look as though they had been in the 
 hands of a careless man. Putting the paper about the cylinder is a little 
 knack in itself. The paper should go down square, fit as close as a glove, 
 and be just as clean as though it had never been touched ; a little practice is 
 required. Having accomplished all this, let the steam in ; don't take the 
 diagram until after the instrument is heated. Take the diagram first as per 
 previous directions, shut off the steam, being careful not to allow any steam 
 to blow through the three-way cock, and the moment this is closed tightly 
 then take the atmospheric line while all parts of the instrument are warm. If 
 the atmospheric line is taken before the instrument is thoroughly warmed up, 
 it will be incorrect ; if it is taken after contraction has taken place by cooling 
 off, even some time after the diagram, it will then be incorrect. Take the 
 diagram first, the atmospheric line afterwards ; then, having noted the steam 
 pressure, knowing the dimensions of the engine in diameter and stroke, and 
 number of strokes or revolutions, put all this data carefully upon the proper 
 place in the card ; be sure and add to it the scale and any memoranda which 
 are necessary, and you will have progressed systematically ; and if you have 
 followed the directions given for handling the pencil, you will have produced 
 a beautifully-drawn diagram, which will give you the correct working of the 
 
8 TWENTY YEARS WITH THE INDICATOR. 
 
 steam, the position of everything and its relation to the economical, or other- 
 wise, handling of the steam. 
 
 THE STEAM WHICH A SPRING WILL TAKE. 
 
 The American Steam Gauge Company give their rule as : Multiply the 
 scale of the spring by 2 \ and subtract 15 ; the result will be pounds of steam 
 pressure from the vacuum line that the spring will take accurately ; as, for 
 instance, 30x2^=7515=60. We think this might be changed with benefit, 
 for it is not always necessary to provide for the 15 pounds vacuum, and it is 
 desirable always to make the indicator diagram as large as can be. For this 
 purpose we adopted some years since the practice of having a set of washers 
 made, which would slip on to the sleeve under the cover on top of the 
 indicator piston cylinder, or upon the shank of the piston itself at the bottom, 
 and these washers vary in thickness from -fa of an inch to J of an inch. By 
 these means we can take 75 pounds of steam with a 30 spring by first block- 
 ing down the pencil lever ; instead of standing, as shown hi Fig. A, it will 
 stand nearer the bottom of the paper cylinder when at rest. There are two 
 things to be guarded against : never under any circumstances undertake to 
 indicate a pressure of steam which shall be beyond the capacity of the spring; 
 for in the one case you will bring up solid, and in the other case, at the top, 
 you will throw the pencil lever out of a parallel line by passing beyond its 
 capacity, and get something which may appear to you like Fig. 135 in this 
 Tolume. It will distort the lines and not do the instrument any good. 
 
 The best oil that we can obtain is pure porpoise jaw oil; ordinary 
 mineral, fl.Tnmn.1 or vegetable oils are affected more or less, and the porpoise 
 oil, which is worth a good many dollars a quart, only requires a very small 
 amount if you use it carefully; this should be used on all parts of the 
 indicator. 
 
 Before we leave the subject of springs, it may be proper to state that 
 the softest spring which can be used, and keep within the limits of its capacity, 
 is the spring in every instance that you should use. The practice is becoming 
 quite common among parties in this country of using 50 and 60 springs, and 
 in other places of using a small diagram, the smaller the better. In every 
 case keep clear of this kind of practice. The larger the diagram, the more the 
 faults of the instrument are shown, if there are any, and the more the faults 
 of the engine builder, if he has been careless in his construction. The only 
 case where we advocate the small diagram is with engines running above 300 
 or 350 revolutions. This will be referred to later. The smaller the diagram, 
 the less real reliance is to be placed upon it, and the cause of this will be 
 found in some of the lessons on high speed, where different diagrams are 
 referred to, and the real reason why the larger scales should be always used 
 will be found with a little reasoning. 
 
TWENTY YEARS WITH THE INDIGA TOE. 9 
 
 CHANGING THE SPRING. 
 
 It is frequently necessary while working upon an engine, for some reason 
 or other to change the spring with varying pressure, speed, or some other re- 
 quirement. There is no reason why this cannot be done in about one minute, 
 providing you have the spring where it is wanted, and understand your work 
 and are careful about it, and there is no instrument we have ever seen that 
 begins to compare with the Thompson for accessibility. Having decided, you 
 must change the spring, commence with the connection of the top of the 
 piston with the pencil lever, taking out the little milled-head screw, then re- 
 lease the pencil bar from the piston, taking notice that the ears on the piston 
 connection have a screw-thread in one and a clear hole in the other side ; hav- 
 ing separated these, then unscrew the cover to the piston casing, lift the 
 whole thing off, piston, spring, cover, pencil lever, etc. Be careful never to 
 drop the piston upon a gritty floor, rather take it in your handkerchief or 
 some other clean cloth ; now unscrew the piston from the under, side of the 
 cover, the spring from the lower end of the piston, put on the other spring, 
 screw it on to the shank on the upper side of the piston, put it through the 
 casing, screw the shank of the cover into the top of the spring ; now put the 
 top of the connecting rod so that the pencil lever will easily drop between 
 the two ears, adjust the screw which passes through one ear, then through 
 the pencil bar, and screw into the other ear on the top of the connection rod ; 
 screw the cover into the casing, after having put a drop of oil on the piston, 
 and see that it works easily back into the casing, and that the piston drops 
 easily into the cylinder and the cover goes down into the casing all easy 
 together, and that the pencil lever, parallel bar and radial lever are all easy 
 and none of them are sprung, having previously taken care that the connec- 
 tions are all blown out, so that no dirt can be blown into the indicator from 
 any of the connections. This can all be done in less time than it has been 
 written in. You are now ready to go ahead. 
 
 GENERAL HINTS. 
 
 Sometimes, in taking the indicator off from the steam connection, it may 
 receive a jar in. such a way that the stand which connects the piston barrel 
 and the paper barrel together may be sprung. We have sometimes found 
 this to be done. There is no necessity for it ; it should never occur. If it 
 occurs, and you are out of reach of help, you may take the thing in your own 
 hands ; but never take a diagram unless your pencil bar describes an absolute 
 right angle line to the atmospheric, and then it is a good plan when this 
 occurs to send it back to the shop to be put into the jig and examined. It 
 may have a crosswise spring, and except a diagram is accurate it is value- 
 less. 
 
 The Thompson Improved Indicator succeeds the Richards' Indicator, 
 which has worked a revolution in engine building. When speed and other 
 matters of importance came up, Mr. J. W. Thompson patented the parallel 
 
10 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 motion, not shown, for it has now practically been discarded, and has been 
 displaced by the Improved Thompson, shown in Fig. A. This instrument is 
 manufactured solely in the United States by the American Steam Gauge 
 Company, Boston. 
 
 GIVING TrtE MOTION. 
 
 Leaving Figs. A and C, a peculiar device is seen, for the lack of which 
 there has been much trouble in times past. Fig. D shows an improved 
 method of taking the 
 motion off the paper 
 barrel. A represents 
 
 the wheel, which is x a^B^k.^W r ^^-^^ W&^^^s^^^^^^^. 
 also shown in dotted 
 lines in a different po- 
 sition ; B represents 
 a stand holding the 
 wheel over which the FIG. D. 
 
 cord passes ; and the end of the stand is a sleeve running into the 
 solid stand shown, the whole thing being bored through ; and the flat 
 part shown at the right is secured against the bottom of the stand by 
 means of a thumb-nut at the lower end of A, B, C. The sleeve which 
 extends into this stand has in its center a groove into which the flat- 
 headed thumb-screw, C, enters, holding it in any position, to the right or the 
 left, up or down, giving it the full swing of the whole circle, and in this way 
 the motion can be taken from any point, at almost any angle that it is possible 
 in the whole 360, either horizontally or vertically. It is one of the improve- 
 ments made by the Steam Gauge Company within the last two years, and is 
 the subject of separate patents. Wherever the old plan of wheels is in use 
 on the old Thompson or the Improved Thompson, this can be substituted if 
 required. All instruments now made are made with the device shown in Fig. 
 D, and this device, as simple as it is, makes it possible to use the instrument 
 in many places where special motions had to be arranged by the old method. 
 
 AMERICAN STEAM GAUGE COMPANY'S AMERICAN IMPROVED DETENT 
 
 MOTION INDICATOR. 
 
 On page IOA is shown the new form of the Detent Motion, changed in 
 this edition of this book for the first time since the first copy was printed. 
 Fig. C shows the front view of the regular Thompson Indicator with a 
 2 inch diameter paper cylinder, which is used up to 300 R. P. M. The 
 Detent Motion is also applicable to their regular high speed Improved 
 Thompson Indicator, having a i^ inch diameter paper cylinder. The \y 2 
 inch diameter cylinder gives a diagram 4 inches long ; the 2 inch diameter 
 cylinder gives a diagram 5 inches long. Otherwise than that the smaller 
 cylinder is used for the higher speeds, there is practically no difference 
 between the two mentioned instruments. 
 
TWENTY YEARS WITH THE INDICATOR. JOA 
 
 The distinctive difference between the Improved Detent Motion Indi- 
 cator and the old Detent Motion Indicator made years ago, is, that the base 
 piece around which the cord goes, which takes its motion from the crosshead 
 of the engine gives motion to the paper cylinder above it, - can, by the 
 
 movement of the lower or right-hand 
 lever shown in the cut, be separated 
 instantly from the paper cylinder, leav- 
 ing the cylinder standing perfectly still, 
 and this is done without any shock 
 either to the cord, to the reducing mo- 
 tion, or the paper cylinder. When 1 the 
 paper cylinder is stopped by this move- 
 ment, it assumes the proper position 1 , 
 as shown in the cut, by means of a 
 spring inside of it, described later on, 
 and brings the paper springs in front 
 or always in the same place, so the 
 fresh paper can be put on. 
 
 The upper handle shown, is con- 
 nected to the movable stand which car- 
 FIG - c ries the pencil motion around, and con 1 - 
 
 nected to the steam piston, and has nothing whatever to do with any other 
 part of the instrument. 
 
 When the lower lever is moved to the right, and the connection cut 
 between it and the paper cylinder, the motion is continued, no matter what 
 the speed of the engine is, and the cord and the reducing motion keep right 
 on about their business. When the lever is moved to cut the paper cylinder 
 free from the motion, the paper cylinder lacks a little of the point of contact, 
 and whenever the operator desires to start the paper cylinder again, he takes 
 hold of the knurled head on the top of the paper cylinder, and turns it, per- 
 haps one-eighth inch, when the connection is made automatically, and you 
 are then ready to take a diagram. This last mentioned arrangement prevents 
 the taking of diagrams when you don't want them, and insures the taking of 
 them when you do want them, and it is very neatly worked out in the instru- 
 ment. 
 
 When the paper cylinder is stopped, it will stand perfectly still. It 
 cannot catch and disappoint the operator. The diagram can be examined, 
 taken off, changed, or the same one may be started again, as above directed, 
 and the whole thing is in the hands of the operator. 
 
 The Detent motion in this case avoids a great many of the troubles 
 incident to the older fashioned methods of combining a Detent motion with 
 a steam engine indicator. There would seem to be no possible chance in 
 this for the breaking of cords, pulling out hook, smashing the pencil motion 
 by the Detent motion engaging when it was wanted to be kept free, or in 
 
10B 
 
 TWENTY TEARS WITH THE INDICATOR. 
 
 not getting the diagram because the Detent motion did not engage at the 
 instant of time when it was expected to do. These old-time troubles would 
 seem to have disappeared entirely. The whole thing is so simple that it 
 might have been discovered many years ago, and could have been put into 
 operation long ago, to the advantage of people who are unaccustomed to 
 handling indicators at a rapid speed. 
 
 This particular indicator would seem to be exceedingly desirable in a 
 great many places around marine engines, locomotive engines, or other 
 places where an instrument must be attached in such a place or at such a 
 point that it is not only very unpleasant getting to it and away from it, but 
 frequently the amount of room is exceedingly limited and in too close prox- 
 imity to very hot pipes or surfaces. This attachment may be applied to 
 either hand indicator, and in almost any position that it is possible to put it ; 
 if the paper barrel of the instrument is in a horizontal position rather than 
 in a vertical one, the Detent is just as reliable and fully as serviceable ; or if 
 you get into close quarters with it, it would seem to have every facility that 
 it was possible to combine in such a small piece of mechanism, which is so 
 very important. 
 
 One of the most important things sug- 
 gested to the writer, is that by this particular 
 application of the Detent motion, the taking off 
 of the paper cylinder is positively and unequiv- 
 ocally done away with. 
 
 It has been a great bugbear to engineers 
 using Detent indicators that it was necessary to 
 catch the paper cylinder at almost the right 
 point in the stroke, or break a cord, or do some 
 other mischief which required time, and often 
 a great deal of trouble, to put again into proper 
 form. The paper cylinder of this instrument 
 cannot be taken off without unscrewing the 
 thumb-nut at the top, and the only necessity for 
 taking it off at all is to clean and oil the long- 
 bearing on the inside. 
 
 Fig. C2 shows the interior mechanism. 
 " Remove the knurled nut F ; take off the paper 
 cylinder, and with a wire clip, (sent with each 
 indicator) , remove the auxiliary spring case H 
 by catching the end of the clip in the notches of 
 the spring case ; turn it forward until it releases from the catches ; then 
 remove the spring and the inner sleeve I ; clean and oil ; replace the inner 
 sleeve I, by inserting into the cylinder so the pin on the outside of the sleeve 
 will enter the slot inside of the cylinder bearing. Turn it until it comes to a 
 stop ; then with the clip catch the auxiliary spring holder H and give the 
 
 FIG. C2. 
 
TWENTY YEARS WITH THE INDICATOR. U 
 
 spring E a tension of about ^ of a turn, and catch the points on the spring 
 case H into the slots provided for them." These are the maker's directions. 
 
 The paper cylinder has a spring which brings it back to its proper position 
 independent of the spring which looks after the cord on the reducing motion. 
 The thing is very simple, very positive. The small paper cylinder instru- 
 ment uses the same spring, pencil, levers, pistons, and fittings that the 
 larger instrument does. Several hundred of these instruments are now in 
 use, and with the very best satisfaction. 
 
 The instrument with 2 inch diameter paper cylinder, or No. i indicator, 
 is adapted for speeds up to 300 r.p.m. At that speed it will take a diagram 
 4^ inches or 4^4 inches long. The instrument with i^ inches diameter 
 paper cylinder, or No. 2 indicator, will take a diagram 3^ inches or 3^ 
 inches in length up to 650 or even 700 r.p.m. 
 
 METHOD OF ATTACHING THE INDICATOR, OR OF MAKING UP THE 
 
 REDUCING MOTION. 
 
 There is probably no one device which has been used so much as the old 
 pendulum, and there is no device which is so generally incorrect or so much 
 misapplied. These pendulums have various faults, and the usurs of them 
 have many vagaries. We recently saw in a large engine-room a pendulum 
 attached to a piece of iron, leading from one girder to another in a fire-proof 
 arched floor, and it is no exaggeration to say that the top of the pendulum 
 chattered from an eighth to a quarter of an inch sidewise, while the strap 
 which passed from one girder to the other jumped up and down as much more, 
 making a most peculiar motion. The string was then taken off at an angle of 
 10 or 15, brushing by the side of the steam-pipe, and was deflected from 
 the straight line between the carrier pulley above and the indicator pulley 
 below more than one inch. It was perfectly useless to attempt to show the 
 party using it that he had errors multiplied by each other into an outrageous 
 accumulation, and that his diagram was worse than worthless for any purpose 
 whatever. The pendulum can be used. It must be firmly fixed at the top, 
 it must be strong enough in its cross section not to spring either edge-wise 
 or flat-wise ; the bottom of the pendulum must in every case start from the 
 actual center of motion, it must travel precisely as far one side of this center 
 of motion as the other and not an iota farther one side than the other ; in 
 other words, it must be exact. If these simple precautions are heeded, then 
 the pendulum becomes endurable, but in taking off the cord it must not be 
 taken from a point near the top at an angle anywhere from 1 to 120, down 
 to the indicator direct on the cylinder. It must be taken at right angles to 
 the central line of the pendulum when at rest, to a point over the indicator, 
 and if only one instrument is to be used, the carrier pulley may be placed on 
 a line plumb over the center of the cylinder, so that the cord leaving the pen- 
 dulum shall leave it at right angles absolutely when it hangs plumb, and pass- 
 ing over the pulley, there is no necessity then for continuing this exactness. 
 
12 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 FIG. E. 
 
 screw-thread at the bottom 
 in 
 
 for a little to the right or left of plumb in that case does not distort the 
 motion ; but if the first portion is not at right angles, then we get distortion 
 of the worst kind. The pendulum may be inverted by the same precautions, 
 as it is sometimes impossible to get a pantograph between the cross-head and 
 the .side of the wall ; or we have, in some cases where we could not use either 
 on account of too much distance at one end and too little at the other, laid a 
 pendulum on its side ; most men would not take pains with this and we do 
 not therefore advise it. 
 
 Instead of the old means of attaching, Fig. E shows what is known as 
 Bacon's Improvement, being a combination patented by our old friend F. W. 
 
 Bacon, made by the American Steam Gauge 
 Company, consisting of five pieces ; the joint- 
 ed links at the right are intended. that the 
 longer parts should be put under the check- 
 nut of the oil cup to which it may be attached 
 on the cross-head ; the shorter parts turn over 
 each other according as the longer parts may 
 be farther apart or nearer together, until the 
 holes match, through which the screw-thread 
 shank, shown at the top with a hole through 
 it, may be used for the pantograph, or the 
 may pass through this 'hole and be used 
 
 the pendulum, as is shown in Fig. F. There are a great many ways 
 of attaching this to different, engines which will be followed up. Fig. 
 E s-hows the parts in detail, Fig. F shows them attached to a pendu- 
 lum, Fig. G shows the top of a post, pantograph, and the Bacon 
 attachment connected to a vertical cross-head, although the cross-head 
 is not shown, it simply shows the method of attachment. Fig. H shows 
 the pantograph attached to a vertical cross-head and the pieces are 
 attached to the shoe at the bottom by 
 simply raising up the nut which holds 
 the slide in, and then gripping them 
 by screwing down upon them again. In 
 both of these methods of attaching 
 the pantograph, bear in mind the 
 rule with reference to the pantograph. 
 The post on the outside must be set 
 at exactly right angles to the center 
 of motion when at rest ; in other words 
 the pantograph must travel precisely 
 as far one side as the other of the center of motion, and not as we 
 have sometimes seen it, forming the hypothenuse of a right angled 
 triangle, working all the distance one way. Fig. I shows another method of 
 connection to the Corliss cross-head, to which all the same rules apply. Fig. 
 J shows the pantograph and the Bacon attachment connected to a horizontal 
 cross-head. 
 
 FIG. F. 
 
 G. 
 
TWENTY YEARS WITH THE INDICATOR. 18 
 
 RULE FOR THE PANTOGRAPH. 
 
 In all these attachments of the pantograph, whether horizontal or veiv 
 ticai (and the pantograph can be used as well vertically as horizontally, if a 
 
 little care be used in attach- 
 ing it, being the simplest 
 and the most correct of all 
 the motions known), let the 
 pantograph be attached as 
 shown in Fig. 0, whether 
 it be the center of the cross- 
 head or one end of the 
 cross-head is entirely im- 
 material, but let that point 
 FIG> H- at which it is attached be 
 
 invariably the exact center of motion. Set the out-post square with the center 
 of motion, and in no other place or position. Now, as the stroke of the engine 
 varies it is necessary to get more or less motion, which can be done by 
 moving the peg-post or peg arm out or in on this line, which has been drawn 
 squarely across with the center of motion. Let the line from the peg-post to 
 the indicator be at a right angle to the center of motion, or in other words, let 
 the line which connects the peg-post of the pantograph with the paper drum ol 
 the instrument, be as nearly parallel with the piston rod as it is possible to 
 get it. If these two simple rules are observed, any engineer can obtain a 
 diagram which is mechanically, geometrically, and mathematically as correct 
 as any other man on earth can do it. We have frequently said before differ- 
 ent audiences, written it ovei and over again : the indicator diagram, the valve 
 motion, the pantograph or the pendulum, are only and simply a combination 
 of right angles. If everything is done exactly on the square, everything else 
 will be exactly right, whether you are working for the position of valves, use 
 of steam or anything else ; the indicator 
 diagram in this case with these two sim- 
 ple rules observed, will be a positive 
 quantity, perfectly reliable, and if these 
 two rules are not observed, it is as per- 
 fectly and as completely worthless as 
 it is possible to be. 
 
 Fig. K represents the pantograph 
 more in detail, with letters of reference. 
 This simple arrangement, like so many 
 other things, we are indebted to George IG< 
 
 H. Corliss for. It has a great variety of names ; it has been called 
 "lazy tongs," "long legs," " pantograph ;" it was originally called and we 
 believe Mr. Corliss himself terms it his " drum motion." It consists of 
 nothing more or less than a system of levers ; these levers must be absolutely 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 of the same length, those shown at A being double and those at B being 
 single. These are pivoted by means of hollow pivots and washers which are 
 
 bushed. The hitch strip is shown at 
 G and the stud-pin or hitch-pole F. 
 When the pantograph is properly ar- 
 ranged the stud-pin F is in the line 
 between C and D, which are the two 
 ends of the pantograph, one being the 
 dead end D, which is fastened to the 
 post, while C is the live end or at- 
 tached to the cross-head of the engine. 
 The point C attaches, where Fig. E is 
 used,, to the two links connected to- 
 gether, so that the pin at the end, C, 
 readily drops through them. If the 
 links have to be used so that they stand 
 vertically, then the little screw-head, 
 shown in Fig. E, is attached by means 
 of the thumb- nut and the taper end at 
 C drops into this screw-head, turning a 
 vertical into a horizontal bearing, the 
 least variation in the location of the 
 pivot-holes in the " lazy tongs " or pan- 
 tograph will be met by an absolute 
 refusal to work at all, and we have no 
 doubt that some of our engineers or 
 mechanics who have attempted to make 
 a pair of " lazy tongs," have had lots of 
 fun out of it, and nobody else been any the wiser ; whether they enjoyed the 
 fun or not, we do not know. Correctly made, the pantograph is complete, but 
 with the slightest variation 
 from correct, it is like the 
 diagram from a distorted 
 motion, absolutely incor- 
 rect and worthless. 
 
 In applying the panto- 
 
 FIG. J. 
 
 graph, let the end C drop 
 into any point on the cross- 
 head to which you can at- 
 tach, or any one of many 
 ways which will readily 
 suggest themselves to the 
 mechanical engineer. The 
 end D may drop into the top of the post, or we frequently build ourselves a 
 little stand of inch boards, four inches wide, braced, and then get two or 
 three hundred pounds of old iron or anything else which is heavy, and when 
 
 FIG. 
 
TWENTY YEARS WI2H THE INDICATOR. 15 
 
 we get it in line, weight it down, square it, have the points C and D exactly 
 level so there will be no weave or strain, or cross motion which will vitiate 
 the correctness of your diagram. The line from C to D must invariably 
 be at right angles to the line of motion of the cross-head, and absolutely in 
 the center of motion ; then shove your post at D out or in to get more or less 
 motion ; put the stake-pin F wherever you want it, and set this peg F so that 
 the line from that to the indicator shall be parallel to the piston or parallel 
 to the line of motion of the cross-head. If you cannot do this, or if from 
 any cause it is necessary to have the peg-pin, hitch-pin or stake-pin, F, 
 further away from the cylinder than the indicator connections are, imme- 
 diately set up a second little stand, and take the cord from the peg F 
 parallel to the motion of the piston and around the guide pulley to the 
 indicator. Whenever the pantograph is properly put up, every point on a 
 line from C to D is a positively true motion, parallel with the guides, varying 
 from nothing at D to length of the stroke at C. Wherever engineers wish 
 to use one motion for several engines there is nothing better than a piece 
 of gas-pipe, ground off, with an attachment which may be fastened with 
 a set-screw to slide up or down to fit different engines ; to this at- 
 tachment may be fastened a socket to catch the D end of the panto- 
 graph while the other catches into the cross-head. By means of a T on the 
 top of the piece of pipe, which has a flange at the bottom for screwing to the 
 floor, are connected two side pipes standing at a right angle to act as braces ; 
 this can be attached to any engine or flange, screwed down, the braces squared 
 and screwed down, the piece that slides up or down put at the proper level, 
 the pantograph hooked on and you are all ready to go ahead. 
 
 THE AMERICAN IDEAL REDUCING WHEEL 
 
 A more recent type of reducing motion 
 and one which is universally used is the 
 reducing wheel. 
 
 Figure N shows the Improved 
 American Ideal Reducing Wheel 
 as made by the American Steam Gauge & 
 Valve Manufacturing Company. It is adapted 
 for all strokes from 10" to 72". Aluminum 
 FIG. N bushings of various sizes are regularly fur- 
 
 nished for strokes from 18'' to 72". The spring box for the take-up is connected 
 by a 3 to 1 gear with the cord wheel spindle. The cord wheel is made of 
 aluminum and is very light, being fitted with a steel sleeve to resist wear. The 
 pitch of the thread on the steel screw on which the cord wheel rotates is 
 the same as the cord, causing the same to wind smoothly on the surface of 
 the wheel and to pass straight over the pulley. The wheel is easily attached 
 to the indicator direct, or may be placed in any convenient position between 
 the indicator and crosshead. It is sometimes attached to the engine frame. 
 The cord must always run in a straight line and passes directly from the 
 
16 TWENTY YEARS WITH THE INDICATOR. 
 
 indicator around the aluminum bushing on reducing wheel, which must be of 
 proper size for the stroke used, and is fastened as shown in cut. The tension 
 of the spring should be sufficient to keep the cord taut at all times. To 
 adjust the spring, remove screw cap which holds the bushing in place, and raise 
 the spring box until the gears disengage, then increase or lessen the tension as 
 desired. A greater tension than is required only increases the wear. 
 Keep the wheel well oiled. 
 
 SLIDING LOOP. 
 
 There are all sorts of hooks, slips, knots, and other matters used for 
 connection ; until within the last few months we have invariably used the old- 
 fashioned, flat, sliding loop, which is about as nearly worthless as 
 anything can be. While doing some work for one of the lines of 
 steamers, our attention was called to a crude idea by the chief- 
 engineer of one of the ships which we have put into shape, and 
 is shown at Fig. L. This is so clearly shown that no descrip- 
 tion is necessary ; it is a piece of brass tube, spun over at the end, 
 finished, holes bored through it and finished, and it is the only 
 thing in the way of a sliding loop we have ever seen yet that was 
 worth talking about or using. The American Steam Gauge Com- 
 pany make them, there is no patent on them, and any one has the 
 right to make them. We prefer always to use a plain hook on the 
 end of the indicator cord, which is attached to the paper barrels, 
 having means of adjusting by use of this sliding loop from 
 FIG. L. large to small or long to short, using as little cord as possible, 
 more especially on a high-speed engine. We prefer this adjustment to 
 anything we have ever seen, for where we are working with water steam, 
 more or less heat, oil, or any of the other accompaniments, no cord will 
 retain its position for any great length of time by any device we have ever 
 used, until we adopted Fig. L, and some method of ready adjustment is nec- 
 essary. We have previously referred to the adjustment of the paper ban-el 
 by means of the cord, and now having proceeded to obtain the diagram, if 
 the directions have been followed, we are ready to commence the computation 
 of the diagrams. 
 
 THE DIFFERENT METHODS OF COMPUTING THE INDICATOR DIAGRAM. 
 
 The indicator Diagram, having been taken, should bear on it memoranda 
 taken with each and every diagram when it conies from the indicator, wher- 
 ever the work may be performed ; this data should bear upon each diagram, 
 or each pair, the diameter of the cylinder, the length of stroke, the revolutions 
 per minute and the scale of spring with which it is taken, for these are the 
 most important elements and without them the diagram cannot be correctly 
 worked. Wherever it is possible to ascertain the percentage, the clearance 
 should also be noticed. Many engineers of late have accustomed themselves 
 to ascertaining the clearance of their engine so as to know precisely what the 
 
TWENTY YEARS WITH THE INDICATOR. 17 
 
 amount is. It is also a good plan to carefully note the pressure of steam in 
 the boiler by the gauge, and also to notice whether this gauge shall be 
 located above or below the line of the cylinder, and whether there is hanging 
 on the gauge a column of water in the siphon several feet in length, or in the 
 vacuum gauge, how or where it is connected, for we frequently find very 
 radical differences between the pressure in the cylinder and the pressure as 
 shown by the gauge. All these items of data are particularly necessary, for 
 if they are clearly expressed, we may then judge pretty well of various 
 peculiar points which so frequently occur on the diagram, and having the 
 data at hand, we can in every case base our judgment upon fact, and know 
 how a certain falling off or back pressure or any peculiarities of steam or ex- 
 haust will be explained by comparison of the data with the fact. 
 
 WORKING UP THE DIAGRAM. 
 
 If the motion has been properly attached to reduce the stroke of the 
 engine, we shall have an accurate card, and without it is accurate, it is not 
 only valueless but a waste of time. Endeavor by all means to keep the card 
 clean and to avoid the possibility of any mistakes. The general unit called 
 for is the horse-power of a diagram ; the unit of horse-power is 33,000 pounds 
 lifted one foot high in one minute. For this reason we use the length of the 
 stroke, the revolutions per minute and the mean pressure of the diagram, and 
 then by computation, obtain the horse-power. Having our diagram before us 
 we proceed to work it up, and the working up simply obtains the mean 
 pressure from an irregular form. There are several ways of working up an 
 indicator diagram ; the one most generally in use, up to five years ago, was 
 dividing the diagram into ten ordinates or lines at right angles with the 
 atmospheric line, and at equal distances from each other, and then measuring 
 by the same scale with which the diagram was taken, the pounds of pressure 
 upon each one of these ordinates, which was exerted on the piston, then 
 dividing the aggregate by the number of amounts, giving the average or mean 
 pressure. But this was crude, it did not take into account little differences 
 which exist, and while not very far from correct, it was far enough to make a 
 very considerable difference as between the correct computation and the one 
 practiced ; hence, this has been discarded for general use. 
 
 Another way, which is virtually the same thing, was to take a narrow 
 strip of paper, perhaps one-eighth or one-quarter of an inch wide, and mark- 
 ing the steam pressure on the first ordinate from the end of the paper laid on 
 the atmospheric line or line of back pressure, then put the first mark on 
 the atmospheric line or line of back pressure of the second ordinate, and 
 mark the top of the second ordinate by another short mark of the lead pencil ; 
 in this way we are simply adding them together. When all the ordinates have 
 been measured (measure them in inches), multiply by the scale of the spring 
 as 20, 30, 40, and divide by the total number of ordinates measured, and you 
 have the mean pressure. But this has virtually the same inaccuracies as 
 the first method of. measuring. 
 
18 TWENTY YEARS WITH THE INDICATOR. 
 
 There is still another way by which many diagrams have been measured, 
 and that is a sort of general average ; taking a piece of glass with a straight 
 edge, it is placed below the steam line and above the lower part of the ex- 
 pansion line, until the two quantities apparently balance each other and a line 
 drawn across the length of the diagram ; its height found, multiply by the 
 scale, this gives the mean pressure. But this, too, has been discarded and 
 for the last few years the planimeter has been used, and is the only correct 
 way to work up any diagram ; the fact that it is named planimeter is another 
 way of expressing the fact that it is for measuring plane surfaces without 
 regard to how irregular their form may be. 
 
 Fig. M shows a modification of the Amsler Polar Planimeter, as made by 
 the American Steam Gauge Company, Boston. Other forms of the instru- 
 ment may be bought if desired. The proper use 
 of the planimeter will reduce any irregular surface 
 to a parallelogram or square by observing its reading 
 carefully, measuring by means of the pointer, and 
 then reading from the index wheel and vernier and 
 obtaining the value as indicated by simply adding or 
 subtracting. The point at the left is a needle point, 
 which should simply be set into the paper on which 
 it is used, and it is better to use a medium, rough, 
 brown paper or blotting paper, something which is 
 not calender finished on the surface, than to use a 
 smoother paper. Having fastened the card, as shown 
 FIG. M. ^ ^6 cu ^ by a COU pi e O f p mg or tacks, commence 
 
 at any point you choose, simply making a mark with the point of a pencil ; 
 traverse the point, shown at the right, over the line of the diagram in the 
 direction of the hands of a watch, or from right to left on the line which is 
 shown. Having pinned the diagram down on the paper (which, by the way, 
 should be upon a smooth board or surface), next adjust the planimeter so that 
 the index wheel, which is graduated about its entire circumference, shall not 
 meet with any obstacle in its course, or anything to interfere with a perfectly 
 free motion. Now obtain the reading. There are a series of figures about 
 the circumference of the index wheel, from one to zero, making ten lines ; 
 each one of these divisions has ten subdivisions, while the vernier, shown at 
 the left of the index wheel, has eleven divisions in exactly the same distance 
 that the large wheel has ten, so that wherever the index wheel stops one 
 division on the vernier will be bound to correspond with a division on the 
 index wheel. We will suppose we start our reading and that the figure 3 is 
 past the zero on the vernier ; we then count that 6 above 3 is a trifle below 
 zero on the vernier. We now cross over on to the vernier and find that 3 on 
 the vernier exactly coincides with a division on the wheel. This makes GUI 
 reading 363. We now travel the index point at the right, around the 
 diagram, until we stop at the same point from which we started. We now 
 find that 5 has passed below zero on the vernier, and that the third line above 
 5 has also passed ; then running up the vernier, we find that 8 stands exactly 
 
TWENTY YEARS WITH THE INDICATOR. li) 
 
 coincident with a line on the index wheel. We have our reading then 538 ; 
 subtract the first reading from this, the result is 175. Now repeat the opera- 
 tion two or three times until you get three readings, which rnay be 175, 176, 
 174 ; they will vary exceedingly little if you pay careful attention to following 
 the lines. The average of these three readings is 175, which is correct. 
 There is no necessity, although it sometimes saves trouble with a beginner, 
 or doubter, to place the zero on the wheel against the zero of the vernier in 
 starting. If this precaution is considered necessary, a few trials, without com- 
 mencing every time at zero, will convince any one that it is entirely unnecessary. 
 We first read from the index wheel the figure which has passed the zero on the 
 vernier ; this we will call hundreds. Then count the lines up until you find 
 which one has passed zero between that and the next figure ; this is tens. 
 Then follow the vernier until a line is found which precisely coincides with a 
 line on the wheel ; this is units. The instrument is exceedingly simple, and 
 there can be no mistake whatever if care is given, for the reading is just like 
 that of a clock or watch may be taken at any point through the day without 
 figuring from twelve o'clock or six o'clock. This gives you the area of the 
 figure in square inches or in fractions of a square inch. In case you read so 
 that zero on the wheel completes the circuit and passes zero on the vernier, 
 you must then prefix 1 to the hightest number previously read. If in the 
 case we have just cited we are working on hundreds, your first reading should 
 be 175, the second 350, and so on until zero passes; you would then prefix 1, 
 which would make it thousands instead of hundreds, and if it passes again it 
 becomes two thousands instead of one. A little practice with the instrument 
 will familiarize any one, and a little pains taken to familiarize yourself 
 with the reading will shortly put you in possession of the key to it, all which 
 is so plain that no mistake need occur. The instrument will work precisely 
 as well backward, but unless care is taken, and you should obtain a diagram 
 which had a compression loop at the top and an expansion loop at the 
 bottom, you might get a negative result which would be incorrect. So, until 
 you are familiar with it, always work it like the hands of a watch or as shown 
 in the cut, from right to letft, following the diagram around in the same 
 direction ; there will then be no possibility of trouble. The planimeter does 
 not make any allowance, but if the work is correctly done you have at once a 
 correct result from the outline, and by the use of the planimeter the different 
 areas of the diagram may be separately measured with perfect exactness, so 
 as to ascertain the value of the vacuum apart from the steam, or the high 
 pressure and low pressure cylinders of the compound can be very accurately 
 measured, without any regard as to whether they are all taken on the same 
 scale or not. 
 
 Another point which is frequently one of great interest, is to measure the 
 difference between the power in the condenser, taking the vacuum gauge, and 
 the result as given by the indicator in the condenser. The line can be drawn 
 to show what would be the result in case the pressure as shown by the 
 vacuum gauge was realized in the cylinder ; so you may get the actual as 
 compared with the gauge result, and in this way make comparisons showing 
 the absolute value of any factor which is contained in the diagram. 
 
20 TWENTY YEARS WITH THE INDICA TOE. 
 
 TO ASCERTAIN THE POWER FROM THE PLANIMETER READING. 
 
 Many of the diagrams illustrated in this work have lines at the steam end, 
 and release end, which are erected at right angles to the atmospheric line and 
 line of vacuum. The length of the diagram, without any regard to its form, 
 whether there be a heavy compression loop on the steam end, or an expansion 
 loop on the other, or any imperfection in release or exhaust, the length of 
 the diagram is the extreme distance from the very ends, and if a little attention 
 is paid to the way these lines are erected, there will be no necessity for any 
 difficulty in getting at the exact area; for, wherever a compression or 
 expansion loop is contained in the diagram, start at any certain point and 
 follow the diagram line as the indicator made it, and the loops, which are 
 resistance, will be taken out of the area by the instrument without any further 
 care on the part of the manipulator. 
 
 Having accomplished the measurement of the area, we now desire to 
 compute the power. In order to save a great many figures it is better to 
 compute a constant for each pound of mean pressure (even if at different 
 speeds) instead of having to do this with every diagram which is worked up. 
 This is produced as follows : Take the area of the piston in square inches, 
 multiply this by the number of feet traveled each minute, and divide this re- 
 sult by 33,000; the result will be the constant which shows how many horse- 
 powers, or what fraction of a horse-power, is yielded by every pound of mean 
 pressure on the diagram. Having the area of the diagram in square inches 
 or fractions of an inch, divide the area by the length in inches or fractions 
 of an inch (farther on in this work will be found a table of fractions 
 of an inch, decimally expressed, for convenient reference), the area divided 
 by the length of the diagram gives a result which may be a decimal or 
 otherwise. This is to be multiplied by the scale of the spring for the mean 
 pressure ; then the mean pressure multiplied by the constant (directions for 
 which are given above) gives us at once the horse-power, and in the simplest 
 possible way. 
 
 If we have, for instance, a diagram measuring 450, which is equal to 4.50 
 square inches, and which is 2 T ^ inches in length, see the table and find that 
 T \ equals .4375 inch. Now, the area 4.50, divided by 2.4375, equals 1.846, 
 which means that a parallelogram 1.846 inch in height would be exactly 
 equal to the irregular figure which has been described by the indicator. If 
 we have been working with a 30 scale we have only to multiply this 1.846 
 inch by the scale 30, which equals 55.380 pounds of mean pressure; multiply 
 this by the constant or number of horse-powers which every pound of mean 
 pressure gives, and you have then the horse-power of the diagram. 
 
 It is frequently a matter of satisfaction to the beginner, in the use of the 
 planimeter, to have something with which to test. This can be very easily 
 arranged by drawing a circle with a pair of pen dividers, one inch in diameter, 
 or any other sized circle that may be desired (we mention the circle because 
 
TWENTY YEARS WITH THE INDICATOR. 21 
 
 it is more easily drawn correctly, as a general thing). Having this, measure 
 it by the planimeter and then see if its reading agrees with the table of areas. 
 This will always give you a test gauge. 
 
 DIFFERENT FACTORS IN THE DIAGRAM. 
 
 It is frequently necessary to ascertain the amount of bank pressure in 
 horse-power, which can be done if the atmospheric line is perfectly taken 
 and the diagram is also correct. The amount of vacuum in comparison with 
 the amount of steam worked, or the'loss in vacuum all of these are interest- 
 ing features ; while if the reader will familiarize himself with the theoretical 
 curve, as applied to any diagram shown in the lessons further on in the work, 
 he can then see what amount of steam, properly handled, would have done 
 the same or more work, perhaps, than is shown by the diagram from which he 
 is working. The planimeter is invaluable for all this. To get the percent- 
 age of the condenser work, as approximating the theoretical, erect the 
 absolute vacuum line, and then measure the exact amount of vacuum as shown 
 by the indicator, and it is very easy to immediately convert the actual into a 
 percentage of the theoretical, taking the theoretical vacuum at 14.7 pounds. 
 Comparison of realized pressure with boiler pressure is frequently an inter- 
 esting matter. Erect the line of boiler pressure, from which you can carry 
 all computation, so as to get at the actual and the theoretical. The plan- 
 imeter measures these irregular forms with absolute correctness, if the operator 
 works with care in tracing the lines, and in a fraction of the time that would 
 be necessary by any other method. 
 
 NECESSITY OF RELIABLE DATA. 
 
 There is frequently a great deal of ambiguity about information obtained 
 from people in charge of different engines. Wherever a man is sent to work 
 with an indicator, there is only one correct way : Pull off the cylinder head, 
 measure the cylinders and the volume of clearance, and make everything as 
 near correct as possible, for very slight differences are frequently fatal to the 
 report on the case, and carelessness is entirely inexcusable, guess-work or 
 assumption very much more so, and we have seen old and intelligent 
 engineers thrown out of court very abruptly, because of some radical error, 
 even though trifling in extent, shown in their report, where they had, to save 
 themselves a few hours' hard work, assumed that because one part was one 
 size, the other was the other, or some other equally trifling matter which was 
 more than vital to the case. While some more careful man had shown in 
 details that such difference existed, and by that means had thrown doubt on 
 the whole of the work of the careless man. Correctness in every possible way 
 is an element of value, and a lack of care or thoroughness makes an indicator 
 diagram absolutely worthless. 
 
22 TWENTY YEARS WITH THE INDICATOR. 
 
 LESSON I. 
 
 BACON'S METHOD OF LAYING OUT THE THEORETICAL CURVE BY ORDINATES. 
 
 Fig. 6 was drawn by Mr. Bacon to illustrate a simple and correct method 
 of delineating the theoretical curve of expansion, which we shall take, as it is 
 properly lettered, upon which to commence our lessons in the general uses of 
 the different lines, and this will be frequently referred to ; it will therefore be 
 
 Fio.6. 
 
 well for the beginner to familiarize himself with reference to this particular 
 figure. For the time being we shall confine ourselves to the outlines bounded 
 by the letters A, B, C, D, E. The line A E represents the true vacuum line ; 
 the line A B the admission line ; B C the steam line ; C D the line of expan- 
 sion; D E A the exhaust line, and as this engraving is made, it represents 
 exhaust and vacuum lines, while the line between D and E running the whole 
 length of the figure and seen above A, between A and B, is the atmospheric 
 line of the instrument or of a high pressure engine These, in brief, are the 
 various lines of any high or low pressure engine. No matter what form the 
 diagram may take, whether it be a finely proportioned one or one that may be 
 full of errors, these lines, in some relative proportion, all exist in every 
 Indicator diagram. The admission line in this case is very nearly perfect, 
 in fact, too nearly perfect, and it would not be advisable in changing the 
 
TWENTY YEARS WITH THE INDICATOR. 23 
 
 valves of an engine to ever produce an absolute right angle for an admission 
 line, except in a very slow moving and low pressure engine; for in a high 
 pressure, fast moving engine, there would be a certain shock by the production 
 of a line of this sort on the Indicator, and it is much better to confine a small 
 amount of steam by shutting the exhaust valve so as to put in compression or 
 cushioning. This would be done by shutting the exhaust valve between the 
 figure i and A on the vacuum line, so that the line, instead of starting from A 
 to go to B, would start from a point between A and the figure i and gradually 
 rise one-quarter or one-third of the distance from A to B. The line of which 
 we are speaking is not represented in the engraving, but would be represented 
 in about the manner we have described. This is very much more advisable in 
 fast moving engines, from the fact that the steam thus confined costs nothing, 
 and it is much better to assist the piston in coming to a stop without having a 
 tendency to go any further, if it were possible. It prevents a strain upon the 
 connections and really assists the whole thing to come to a stand-still while the 
 crank passes the absolute center. 
 
 As we progress in this study of lines, a very considerable change will be 
 observed in the steam line as well as in the admission line. Upon this point 
 of admission line a great many good engineers run away with the theory that 
 they can tell as well by the lead of the valve, as by the Indicator, what the 
 steam line of an engine is. It is just as well to disabuse yourself of any 
 preconceived ideas, for they are simply and only guesses, and no living man 
 can tell anything about the lines made by the action of the steam in the 
 cylinder, by any marks, figures/ or computations, and only until he applies 
 the Indicator, does he know anything about what is going on. He can 
 theorize and suppose, but it is simply and purely theory and supposition. 
 There is nothing actual or absolute about it. 
 
 We now come to the steam line, B C. The diagram here represented is 
 one which is like what would be taken from an automatic cut-off engine in 
 which the point of cut-off is controlled by the action of the governor, either 
 by changes in the pressure of steam or by changes in the load. This class of 
 diagrams is different from those of other engines. This may be described as 
 admitting the full pressure of steam for a limited amount of stroke, the 
 steam is then cut off and expansion finishes the stroke. The other classes, or 
 groups, are described by a valve having an invariable motion, but with more 
 or less lap, which closes the valve for a portion of the stroke, always cutting it 
 off at a certain fixed point, the pressure being changed by the throttle -valve 
 of the regulator. 
 
 There is still another class, which is virtually a subdivision of the one we 
 have last mentioned, in which the motion of the valve may be changed by 
 hand, either by link motion or an independent cut-off gear. Both of these 
 classes use a regulator in the pipe which governs the pressure of steam 
 admitted through a portion of the stroke ; that portion of the stroke remains 
 
24 TWENTY YEARS WITH THE INDICATOR. 
 
 constant it is always the same. This is the case in the Huntoon, Judson, 
 Waters, and many other governors of that class, which regulate by means of 
 a valve in the steam -pipe, governing the amount of steam required by a fixed 
 motion of the valve, instead of, as in the previous case, the automatic cut-off, 
 like the Corliss, Lawrence, Porter-Allen, and others, in which the full boiler 
 pressure is admitted for a length of the stroke, which is controlled by the 
 governor. 
 
 There is only one other class of engines, and that is the old style plain 
 slide valve engine, having an invariable motion without lap of any amount, so 
 that the steam follows the piston for nearly the whole length of the stroke. 
 In some cases, the mean pressure in the cylinder is adjusted by changing the 
 point of cut-off, as in an independent cut-off gear ; but these engines are only 
 applicable to work in which there is very little or no variation in the load, and 
 they are not at all applicable to the modern system of working, where accuracy 
 in the speed is one of the important requirements. 
 
 In the consideration of these various classes of engines, we shall first look 
 after the automatic cut-off, because it is the most effective, the most economi- 
 cal, and by far the most used. Its lines are always defined. They may or 
 may not be correct, but in some of the classes to which we have referred, it is 
 extremely difficult to ascertain where one of the lines commences or another 
 one leaves off. 
 
 The steam line, B C, is one of the important lines of the diagram. It is 
 very frequently the case that the line, B C, drops away from C, sometimes 
 more, and sometimes less. The engine that comes nearest to good prac- 
 tice will maintain its steam line as nearly as possible to a straight line ; and 
 wherever any considerable variation is found, it may result from one of several 
 causes principally two causes; the first may be an insufficient supply from the 
 boilers to the chest of the engine that is, the steam pipe is not large enough, 
 or the valve may not be as large as the pipe ; and, in the other case, to a very 
 late and incorrect opening of the steam valve. In either case, the lack of a 
 good steam line is a lack of economy. The opening of a valve, or an insuffi- 
 cient area in the ports, may also combine to produce an imperfect, throttled, 
 or wire-drawn steam line upon the Indicator diagram. The steam line should 
 therefore approach closer to boiler pressure, and should be as nearly as 
 possible at right angles from the line, A B, until the cut-off valve closes. The 
 piston, in traveling from B to C, is influenced by the total boiler pressure. 
 When the piston, in its track, reaches the point, C, the steam valve is closed. 
 Now commences the line of expansion. The perfection of this .line depends 
 upon various and important causes. The cut-off valve should close instanta- 
 neously ; the valve, in its action, should work quick, or else we shall have an 
 exaggerated expansion line ; because, if the valve works slowly or imperfectly, 
 it will commence to reduce the pressure, and will still be admitting steam, so 
 that the line of expansion may be plus at one point and minus at another, 
 
TWENTY YEARS WITH THE INDICATOR. 25 
 
 when proved by the theoretical curve. Only the Indicator can tell us whether 
 the engine is constructed properly, or with a capability of doing this properly 
 and correctly, and when the valve closes it must be tight. If any steam 
 leaks, or is drawn under the valve after it is closed, it is a waste of steam, and 
 is certainly not an improvement upon the working of the engine. But these 
 points must be treated upon as individual cases rather than as collective ones. 
 
 We now come to the consideration of the line, C D, which is the curve 
 formed by the expansion of the steam from a higher pressure to a lower one, 
 by increasing the room in the cylinder, by the motion of the piston, from one 
 end to the other. This is usually known as Mariotte's law : that the pressure 
 of steam diminishes in proportion to its volume ; in other words, that steam, 
 at 100 pounds, expanded into double the room, would give a pressure of 50 
 pounds ; and into four times the room, 25 pounds. The use of the theoretic 
 curve is a very considerable and valuable one ; but only as a means of com- 
 parison, no man has yet shown that steam does expand as Mariotte laid down 
 the law as given. By its proper application we erect a theoretically correct 
 diagram, in other words, a perfect diagram. Now, the line of the perfect 
 diagram, if properly done, with the proper data, shows what the engine should 
 have done with the amount of steam and the ratio of expansion, as applied to 
 that individual circumstance. In this way we get a theoretical diagram erected 
 from the data of the actual diagram, and we can then ascertain whether the 
 actual diagram is a large or small percentage of the theoretical. The curve 
 erected from C to D, illustrates Mr. Bacon's method of easily ascertaining just 
 what the theoretical curve should be. The ordinates are here erected, making 
 ten spaces, or divisions ; he cuts off the steam at the second ordinate. If the 
 pressure be sixty pounds from A to B, and be maintained from B to C, it is 
 cut off at two ordinates. The pressure at which the next ordinate should 
 measure is two-thirds its former; and then, as will be seen by his method, 
 two-fourths, two-fifths, two-sixths, two-sevenths, two-eighths, two-ninths, two- 
 tenths. Theoretically, this is correct. If the curve given by the instrument 
 should be above the theoretical curve, we conclude that the steam valve leaks. 
 But if we find the curve made by the Indicator falling below the theoretical 
 line, we are certain that either the piston or the exhaust valve leaks, or that 
 we have discovered something new, which is not likely, however, to be the 
 case. This line varies greatly in different engines. 
 
 To apply the theoretic curve to any diagram, add the clearance between 
 the piston and cover, or head of the cylinder, to which add the area of the 
 ports and passage ways clear to the face of the valves ; reduce this clearance 
 to cubic inches, then ascertain the actual number of cubic inches in the stroke 
 of the cylinder, and get the percentage or proportion of clearance to the vol- 
 ume of cylinder. If the stroke of the cylinder has two thousand inches, and 
 the clearance is fifty inches, the percentage will be one-fortieth, or two and 
 one-half per cent. ; now add one-fortieth to the length of your diagram, then 
 
26 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 draw the line of perfect vacuum, from which all the calculations must be made. 
 Whether the engine is high or low pressure makes no difference. Having 
 added the clearance line, and the line of perfect vacuum, then divide the 
 length of the diagram into ten parts, or spaces. If the steam is expanded, 
 four times the terminal pressure will be one-fifth of the initial. This will be 
 above the atmospheric line of the instrument not above the true vacuum line. 
 
 LESSON II. 
 
 IN this lesson two diagrams are shown, which are as radically different as 
 is possible, in the action of the valves and the steam, so far as principle is con- 
 cerned. In reading these diagrams, it is necessary to remember one point, to 
 which we have previously referred; that is, that the Indicator, when properly 
 
 applied, records absolutely the performance that is going on inside the 
 cylinder. We must educate ourselves to read these lines properly and 
 correctly. The Indicator is simply a mechanical appliance. It does not. in 
 any event, do anything more than record the processes which are taking place 
 inside the cylinder. We must properly apply and manipulate it, and then 
 draw our deductions from its lines, from knowledge gathered from experience 
 and contact with it. 
 
 Fig. 7 is a diagram taken from a Corliss engine. The real vacuum line 
 has been drawn, while the atmospheric line extends from O, on the right, to A, 
 on the left. Two lines are erected, one of which is the right angle from which 
 
TWENTY YEARS WITH THE INDICATOR. 27 
 
 to measure the length of the diagram ; and the line at the extreme right is the 
 clearance of the engine, added for the purpose of putting in the expansion or 
 theoretical curve, which is shown by the dotted line. This diagram, in itself, 
 is quite a study. Theoretically, it is almost absolutely perfect. Four motions 
 of the piston are recorded by the pencil mark of the Indicator, and if careful 
 attention is given to the dotted line, it will be seen that the valves of the engine 
 were almost absolutely tight ; that very little condensation took place, and that 
 the termination of the correct expansion curve at A, is as nearly correct as it 
 is possible in actual practice to obtain one. This diagram is divided in two 
 directions the lines from right to left being at five pounds, with the scale 
 used, so that the pressure at any point upon the diagram can be shown without 
 using the scale. The ordinarily used ordinates, and the clearance line erected, 
 complete the lines of the figure. If we study the lines near the upper right 
 hand corner, the line drawn by the pencil of the Indicator is at a little distance 
 from the inner line of ordinates. A little space will be seen between the inner 
 line and the steam line near the figure 75. Whatever proportion this distance 
 shall bear to the whole length of the diagram, just that proportion of the 
 stroke the piston had moved on its outward travel before the valve opened 
 sufficiently to admit the steam to the pressure denoted by the line. In other 
 words, steam was admitted somewhat late. This is a very common observa- 
 tion where engines have been running any length of time. The steam -line of 
 this engine, as we have before stated, is almost perfection. It does not 
 diminish in pressure, but follows along very squarely, and wherever the valve 
 closes, or cuts off, the pressure instantly drops, the corners are very little 
 rounded, and in the expansion line it will be seen that very little expansion 
 occurs. The serrations in the line at the second ordinate, between the figures 
 40 and 67, may be made by either one of several causes ; it may be due to a 
 trifling oscillation in the instrument, to the presence of water, or to a very 
 insignificant leak; we are supposing the instrument is in perfect order and 
 condition. As the ratio of expansion increases, the line more closely follows 
 the theoretical line, and it will be noticed that the four lines are all merged 
 into and apparently cross one another at almost the same precise spot. Had 
 the steam valve been leaking, or had there been much water in the steam, the 
 line under the figure 7^ would have risen considerably above the theoretical 
 line, and this is very commonly found, but in this particular case the 
 valves were tight, and the line continues down to its complete expansion, or 
 termination, almost absolutely. 
 
 Fig. 8 is a very different diagram, and was taken from a steamship engine ; 
 and this may properly be termed one of the vicious forms, or at least a vicious 
 diagram ; and even now, we find some men so antiquated as to advocate this 
 method of working steam. It must be read, not from its comparison with the 
 other, so far as the Indicator goes, but as an absolute result given by the Indi- 
 cator of what was being done in that engine at that time, and we can then 
 
28 TWENTY YEARS WITH THE INDICATOR. 
 
 compare it with Fig. 7, each diagram being the positive production of a differ- 
 ent engine, given by the same Indicator, perhaps, just the same as a pair of 
 scales would weigh a pound of sugar or a pound of nails. The work done 
 by the scales is simply a mechanical result, while the matter, which passes the 
 hands of the operator of the scales, may be as entirely dissimilar as sugar and 
 nails. This diagram has in it some very peculiar points. 
 
 Fig. 8 is taken upon a scale of twelve pounds to the inch. The line, 
 A O B, is the atmospheric line, while the line, C D, is the line of perfect 
 vacuum. We have previously spoken of compression. It is illustrated in 
 this diagram, and we shall commence at /, in the right hand corner, where the 
 piston, on its return stroke, in passing /", commences to compress the steam 
 which the closing of the exhaust valve has confined. The operation in this 
 case would seem to reach about five pounds above the atmospheric line ; at a, 
 the steam -valve has opened, and the steam is admitted, carrying the pressure up 
 to b. Then the piston starts upon its forward stroke. The continued opening 
 of the valve maintains the pressure at almost the initial point. When the 
 piston has traveled forward to c, the steam -valve commences to close, and 
 continues to close, but the actual point of closing cannot be ascertained from 
 the diagram without geometrical delineation ; but had the valve been properly 
 closed at c, as it should have done with an automatic engine, then the dotted 
 line, eg, would have been approximated very nearly by the steam -line, the 
 lines, eg, being the theoretical expansion curve from the point, c, and the line, 
 d y the real expansion curve of the engine. At d the exhaust valve com- 
 
TWENTY YEARS WITH 7^HE INDICATOR. 29 
 
 mences to open and the condenser to do its work in producing a vacuum. 
 The vacuum in this case is about twelve pounds. The notch in the line, 
 between e and/, is caused by the fact that the air was expelled, or that the 
 condenser had then produced its maximum effect. The line here, <?/ will be 
 seen to drop from 9 below to 12+. When the condenser takes hold at d, the 
 steam has expanded to only two pounds above the atmospheric line, the 
 piston has not reached the full length of its travel, and the condenser seems 
 not to have the capacity to take and produce a prompt vacuum. When the 
 engine reaches its center, on the outward stroke, it will be seen at q that the 
 line of the instrument drops vertically. At e, the piston has commenced its 
 return stroke. Only nine pounds vacuum has yet been attained. As the 
 piston travels on its return stroke, the condenser commenced moving again, 
 and the vacuum is steadily reduced from 9 to 12 in about one-seventh of the 
 return stroke. 
 
 We are now to return to the expansion curve, real and theoretical. The 
 area bounded by the line, c d g, and eg, is really just the same as so much 
 steam thrown away ; for, had the valve closed at c, the line, c g, would have 
 been produced ; but as the valve was so slow in its closing, the quantity of 
 steam admitted led the real line of expansion unusually far above the theoret- 
 ical ; and while a certain amount of power was produced, it was at an 
 enormous expense compared with the rest of the area of this diagram, really 
 at no positive advantage. 
 
 In comparing the two diagrams, Fig. 7 shows the perfection of the 
 working of steam, and Fig. 8, we might with propriety say, the perfection of 
 waste of steam. Although the one is called a high, and the other a low 
 pressure diagram, had a condenser been attached to the engine from which 
 Fig. 7 was taken, there would not have been the least difficulty in producing a 
 better vacuum than that of Fig. 8, and the waste between the two engines 
 would be enormous if they were both adapted to the same work. 
 
 We shall, in another lesson, show a diagram from a modern steamship 
 engine, which is as radically different from Fig. 8, as Fig. 8 is different from 
 Fig. 7. The figures upon these diagrams are the old method of working up, 
 and it will be good practice to work these over and corroborate the figures, 
 or to make a nice tracing of these diagrams, lay out the curves, and find the 
 percentages of economy and waste. 
 
 There are high pressure engines, now running, which are fully as wasteful 
 as Fig. 8, some of which we shall illustrate ; but it must be borne in mind that 
 this diagram was taken a number of years since, when it was supposed a great 
 improvement had been made in working steam expansively upon marine 
 engines. Many marine engines have most elegantly-contrived expansion 
 valves, or arrangements, which we shall treat upon more fully. Fifteen years 
 ago it was supposed that some of the steamships crossing the Atlantic had 
 reached the highest point in the economy of fuel ; but, within the last eighteen 
 
30 TWENTY YEARS WITH THE INDICATOR. 
 
 months, vessels, with more tonnage than those with which the comparison was 
 made, have crossed, from New York to Liverpool, upon a little less than one- 
 fourth the amount of fuel per day than the engines are using which were sup- 
 posed to be so economical; while, in other departments of working steam, 
 results have been obtained, by the application of steam pumping of water, 
 which far surpass the performance of any steamship engine that has been built 
 up to this date. This has been done, partially, by studying carefully the 
 force, and its application to raising water ; but if the steam mechanism had 
 not been as nearly perfect as it is possible to make it, it would not have shown 
 such immensely economic results. The perfection of application of the power 
 produced has wrought out this result to which we shall again refer. 
 
 The study of this diagram, by those who are not entirely familiar with the 
 Indicator, will be of great value. No man should be intrusted with the run- 
 ning of large engines, especially in cotton or woolen mills, where perfection of 
 speed is required, and where the best results that are possible are not only 
 desirable but, from an economic point of view, are a most imperative necessity. 
 Many of our larger corporations now require that an engineer shall have a 
 practical knowledge of the Indicator before they will put him in charge of 
 their engines and boilers. The time for setting the valves of an engine by the 
 eye, or by scratches or punch marks, has ceased to exist in the eyes of intelli- 
 gent and competent engineers ; and the engineer of the future is probably a 
 man who is capable of a careful manipulation of the Indicator, and of producing 
 the highest economic results from following the lines drawn therefrom, without 
 regard to the whims of the builder, owner, or others, after he has qualified 
 himself to read these lines, and make them by the proper manipulation of his 
 instrument. 
 
 LESSON III. 
 
 IN this lesson we present two diagrams from different classes of valve 
 motions, and the two figures represent as radical a difference as is possible, 
 from the two practices, in the way of working steam, but by this time the 
 reader should be quite able to read the lines. In Fig. 9 we have a diagram of 
 rather peculiar appearance, and yet it is not many years ago that a great 
 many engines were working under circumstances no more favorable than is 
 shown by this card. It is a low pressure condensing engine. The steam is 
 carried half the stroke, the pressure being regulated by the throttle valve in 
 
TWENTY YEARS WITH THE INDICATOR. 31 
 
 the pipe, but the admission line is a little late. The steam line is very well 
 maintained, but at what an expense ! While the expansion line is somewhat 
 irregular, and is much higher at the termination than it should be, from the 
 fact that the valve which is used in this case did not close promptly enough. 
 The condensing is almost a farce. It will be seen that the valve opened very 
 slowly, or that the condenser took hold very imperfectly ; and the piston had 
 returned nearly half its stroke before the condenser had attained the maximum 
 vacuum, while the distance between the return line of the steam and the line 
 of absolute vacuum is about equally divided. In other words, the vacuum is 
 just about half what it should be ; the atmospheric line of the instrument 
 running through the Indicator lines, and the absolute vacuum below, without 
 measurement we should say it was about one-half, and yet there are engines 
 running today in just this kind of practice. This engine uses double the 
 
 FIG. 9. 
 
 steam in amount, at half the pressure, and the engine only affords about half 
 the vacuum. It is therefore utilizing something less than one-third of the fuel 
 that is burned in the furnace. 
 
 Fig. 10 we have chosen for an especial purpose. It is a fine outline; the 
 compression is an elegant line ; the steam valve opens at just about the right 
 point, and the admission line is correct. The expansion line looks well to the 
 eye, but the style of engine is one that makes a fine diagram, and most 
 essentially misleads the unpracticed eye in its reading. The diagram in ques- 
 tion is made from a non-condensing engine, at a slow rate of speed, from what 
 is known as the Sickels valve-gear, using single or double poppet valves. 
 
 The clearance of this engine, by reason of the valves used, is enormous, 
 but they have a chronic way of leaking, so that the expansion line in this 
 engine, except the whole clearance be known, is of no use whatever in erecting 
 upon it a theoretical curve in order to measure its efficiency. And while the 
 outline is agreeable, with the exception of the undulations in the expansion 
 curve, it bounds a waste of fuel that would not be tolerated today by any sane 
 man who had to pay for fuel himself, and could not be used by any concern 
 who paid for their fuel or meant to pay their bills. When the valves and seats 
 
32 TWENTY YEARS WITH THE INDICATOR. 
 
 are new and tight, it works with much more economy than when any little 
 trouble has arisen from the wear of the valve. But the clearance is so very 
 large that economy is absolutely out of the question. The question has several 
 times been asked us: Is it possible for an engine that is not economical to 
 make a handsome Indicator card ? This is an example and an answer to that 
 question. 
 
 The Indicator card, in itself, is of very little value, except all the circum- 
 stances that surround it are made known from the positive standpoint of 
 absolute measurement. In this case, if the actual clearance was known, the 
 termination of the line of expansion would, without doubt, be above the 
 proper termination of the theoretical curve ; for the clearance is very large, 
 and whatever amount of clearance is found in an engine is a constant quantity 
 that must measure out an amount of steam, which does no good beyond rilling 
 a certain amount of dead room at every revolution of the engine. 
 
 FIG. 10. 
 
 t "-' - --"- - ' 
 
 As steam is a fluid which is capable of measurement just as much as 
 water or milk, do not allow an engine builder to talk you into the use of a 
 large clearance, by any roundabout method of argument ; for if you are using a 
 cut-off engine, the amount of steam wasted in the clearance must be filled with 
 live steam, while the valve is open, and the ratio of expansion has nothing to 
 do with it. The amount of steam which you measure out in this way is for 
 each end of each revolution, and the waste is therefore as many times the 
 excess of clearance as your engine makes strokes per day, month, or year. 
 
 In Fig. 10 there is positively no back pressure, and back pressure is no 
 more necessary in a well constructed engine than a leaky piston head ; and 
 except some obstacle is offered to the exhaust, an engine should exhaust at no 
 back pressure, without some visible, sensible reason, as in the case of very 
 extended exhaust pipes, exhausting through small pipes to heat rooms, or 
 some such reason as that. An engine making the card, Fig. 10, although high 
 
TWENTY YEARS WITH THE INDJCATO& 
 
 33 
 
 pressure, will do nearly, if not quite, double the work with the same coal as 
 the engine which makes the card, Fig. 9; while if Fig. 10 should be set, to 
 work with a proper condensing apparatus, it would do a very large percentage 
 more than the engine upon which Fig. 9 was made, with the same amount of 
 coal. '.' >-*i ovtnv 
 
 LESSON IV. 
 
 IN this lesson we shall come at once to the practical. Both diagrams 
 shown are from the same engine, and taken upon the same day. 
 
 FIG. ii. 
 
 Fig. ii is not an uncommon diagram, although this was from a modern 
 built cut-off engine, by Wheelock. The engineer in this case had beconie 
 dissatisfied with himself and everybody else, and he was one of those men who 
 do not consider an Indicator of any practical value ; consequently he had 
 placed the valves in such a position as he knew was correct. The result 
 proves that he was not correct. The line at A represents the steam pressure 
 in the boiler, and is the same in both figures, and it is erected at right angles 
 to the atmospheric line of the instrument. Mr. Engineer, in making his 
 changes, made the motion of the valves very late, as will be seen at B. The 
 
$4 TWENTY YEARS WITH THE INDICATOR. 
 
 valve did not commence to open till after the piston had started on its stroke, 
 and the old saying, " a stern chase is a long one," was never better exemplified 
 than in this case. The valve being late in its opening, is late at every portion 
 of the stroke. The steam line in this case rises after the piston starts, for 
 when the valve gets wide open it admits more steam than it did at first. The 
 expansion line is a rather awkward affair, while the exhaust resembles an old- 
 fashioned shoe toe, and it is evident the engine has too much back pressure. 
 At C there is a peculiar little point, caused by the late closing of the exhaust 
 valve; and after the piston stops, the Indicator seems to drop a couple of 
 pounds. From C to B the admission line is very poor. 
 
 FIG. 12. 
 
 Fig. 12 shows the diagram a couple of hours afterward, and which pre- 
 sents a very different appearance indeed. In this case, the admission line does 
 not come fully up to the boiler pressure. The steam line is hardly maintained 
 as it should be, it is a very great improvement over Fig. u, but the im- 
 provement is not entirely in the outline. 
 
 On these diagrams there is another very serious question. Fig. 1 1 was 
 not doing any more work than Fig. 12, in fact, it was running the very same 
 machinery, and did not run it at quite full speed, while the amount oi coal 
 used to produce Fig. 1 1 was sixteen tons, and that used to produce Fig. 12 was 
 twelve tons in the same time. Now, this evident discrepancy was not from 
 any particular fault in the engine builder, but all lay in the fact that the engi- 
 neer knew very much better, in his own estimation, than he did as a matter of 
 fact, what should be going on inside the engine cylinder, and this is a very 
 common mistake. 
 
 Fig. 12 shows very much less back pressure and earlier exhaust, and a 
 slight amount of compression, but sufficient to arrest the motion of the piston. 
 
TWENTY YEARS WITH THE INDICATOR. 35 
 
 The steam valve commences to open just about early enough, and the steam 
 is carried a little less than one-half as far on the steam line in Fig. 12 as it is in 
 Fig. 1 1 . The consequence is, less steam is admitted to the cylinder to do the 
 same work, less steam is exhausted, and very much less is wasted, and only by 
 the simple and proper placing of the valves. 
 
 Sometimes men reason, although very falsely, that they can tell by the 
 motion of the valve, or the exhaust, or something else, how the engine takes 
 steam ; but, as a matter of fact, no person can tell anything about it till after 
 the Indicator is applied, and not then except the application be strictly cor- 
 rect, and whoever reads it must have had some practice in reading the lines 
 of a diagram. The two figures are as unlike as it is possible to make them, 
 while the serious question is : Why should not any engine make Fig. 1 2 as 
 well as Fig. 1 1 , while it costs less to make it ? And the only answer is that 
 the engine will make it if you have an engineer who is willing to steer by the 
 Indicator. There is no trouble whatever in doing this ; but the fact is, engi- 
 neers do not always like to learn, and in many cases parties in charge of 
 manufacturing establishments do not furnish their engineers with the materials 
 with which to work. 
 
 This is only a single lesson, but what is very frequently done, and as a 
 rule the men who do it are not the engineers. If the reader will figure both 
 these diagrams from the same data, they will find a very serious difference, 
 and this difference is WASTE to the owner, and is precisely the measure of 
 difference between a good and a poor engineer. There is no material differ- 
 ence in the amount of work done, although, as a matter of fact, the same 
 machinery was run at the same speed, in each case, by the very same engine; 
 and it will be good practice to figure the difference in an engine of 18 X 42, 
 running 65 revolutions, and see how much was wasted. 
 
 LESSON V, 
 
 - ' ' -vV 
 
 IN this lesson we have two interesting subjects. One, a high speed 
 engine, 12^2 by 16 inch cylinder, running 160 revolutions, diagram with a 50 
 spring. This diagram (Fig. 13), as a general outline, approximates very 
 closely to locomotive practice. The engine takes steam at A, and the steam 
 is shot into the cylinder, and immediately decreases in pressure to a very great 
 extent, from A to B, perhaps we have made the line a trifle too long, 
 about one-third of the stroke. This is very nearly the steam line. The 
 pressure at A is 75 pounds. At B it is 50 pounds. We have no data upon 
 
TWENTY YEARS WfTH THE INDICATOR. 
 
 which we can figure or lay out the curves. Hence, we cannot say whether the 
 expansion line of the diagram is correct or not. The exhaust valve opens at 
 A B, nearly one-sixth of the stroke. The exhaust line is very good. There 
 is no back pressure, but the exhaust valve closes again very nearly at C, which 
 is one-half of the stroke. The compression line in this case is well formed, 
 but whether it is an economical one or not can only be judged by data which 
 we are not possessed of. The outline of this diagram is peculiar, to say the 
 least, and we have no doubt it is interesting, if we had the whole facts, from 
 
 FIG. 13. 
 
 which we could make deductions as to its economy, or otherwise. The steam, 
 in this case does not obtain access to the piston as readily as it should. The 
 line, A to B, indicates what the steam line at induction pressure would be, for 
 whatever length of stroke it is carried; and the line from the horizontal to B 
 shows the pressure line from the opening of the valve to the cutting off. The 
 clearance of this engine, although very small, shows a very good expansion 
 curve, Bu-t if the clearance exceeds 4 or 5 per cent., the curve would not 
 rank well. We do not rriean^ well as to the ideas of some engineer or builder 
 we mean well as to the coal pile. 
 
 
 FIG. 14. 
 
 Figs. 14 and 15 are from a Corliss engine, and in both these cases the 
 steam valve opens late. The admission line is therefore tardy. The steam 
 line m Fig. 15 is somewhat peculiar, as it carries the induction pressure very 
 
TWENTY YEARS WITH THE INDICATOR. 37 
 
 squarely for a short distance, when it drops off; and, 'from the formation of the 
 line, we should infer more steam entered the cylinder. We have not, in this 
 case, the clearance upon which to erect a theoretical expansion curve. Our 
 purpose is not to treat this diagram from a theoretical stand-point, but to draw 
 from it a practical lesson for those who are not too hard-headed to learn. 
 This is another expensive practical lesson, where men overreach themselves 
 in their attempt to do their own engineering. The cylinder of this engine is 
 23 inches in diameter, 60 inch stroke, 75 revolutions. The diagrams are taken 
 with a 40 spring. 
 
 Fig. 14 shows more back pressure than Fig. 15. In either case the 
 amount is very, large. From the time the engine takes steam until the valve 
 closes, and the admission of steam to the cylinder is stopped, a considerable 
 decrease of pressure upon the piston is shown. The shape of this line tells 
 the practiced eye plainly that there is some reason for it. The line, for a 
 portion of its distance, is almost a right angled triangle, or two sides of it, 
 when compared with the upright line, A. The formation of the line, therefore, 
 shows that the cylinder is calling for more steam than the port is able to 
 supply. In this case, the reason is a very simple one. The parties who are 
 
 FIG. 15. 
 
 running this engine bought a 200 horse-power machine ; it is indicating 350 to 
 380 horse-power, or nearly double what it was ever intended to do economi- 
 cally. Investigation into this question, of a very recent date, by a competent 
 engineer, develops the fact that the engine is working at double the load it was 
 ever intended for, and, with all its disadvantages, upon 29 pounds *of steam per 
 indicated horse-power, upon a test; These diagrams do not show an econom- 
 ical use of steam, from the fact that the load upon the engine is so large that 
 the ratio of expansion is entirely too small. More steam is required to drive 
 the load than the steam -ports will properly handle, so far as economy goes. 
 That is to say, the amount of steam required at each end of each stroke, is so 
 much, that the capacity of the ports will not admit it all, at the pressure 
 required, or furnished by the boiler; that the amount of steam admitted is 
 
3 8 TWENTY YEARS WITH THE INDICATOR. 
 
 more than will be admitted at boiler pressure ; and upon the other end of the 
 stroke, the volume of steam, after expansion, ; s more than the exHaust ports 
 will readily relieve the engine of; so that a loss is made at both ends, a 
 radical loss of initial pressure, and a loss of resistance by back pressure after 
 the steam has expanded, or done all its work. For all this fault there is only 
 one remedy: less load, or a larger engine. In this case, we presume the 
 engine will be charged with what is really the fault of the owners or managers, 
 and, without much doubt, they will be entirely blind to the fact that they are 
 themselves the cause of a costly steam power. Our next lesson will show a 
 modern built engine, which the reader will do well to contrast with this over- 
 loaded Corliss. It is no use to expect to load a 300 horse-power engine to 
 560 horse-power, and get an economical result in the use of steam. But there 
 are people in the world who are just complacent enough to suppose that one 
 pound of coal will do an immense amount of work if they only direct the 
 way in which it shall be used. 
 
 In these lessons we have nothing to do with the theoretical, beyond the 
 simple comparison, believing that, as facts are facts, and these examples are 
 all from actual use, our readers, who are honest with themselves and can 
 learn from example, cannot fail to profit by them. In too many cases the 
 use of steam is an expensive luxury, and the overloading of an engine is not 
 the least expensive. And aside from the danger incurred, the liability of a 
 complete smash-up or stoppage, it must also be borne in mind that all of these 
 circumstances tend to involve danger to the lives of all those immediately in 
 reach, and this is a factor which is not always taken into account or 
 consideration. 
 
 LESSON VI. 
 
 IN this lesson we have a rather interesting and instructive subject. The 
 diagrams furnished are both from the same engine, are from actual practice, 
 and were taken for the purpose of ascertaining what economy the engines are 
 working with. The size of the engine is 6 X 14 inches, running 220 strokes, 
 or a trifle more, giving an indication of -f- 17 horse-power, with an assumed 
 clearance in the construction of the theoretical curve of three per cent, of the 
 volume of the cylinder capacity. Subsequently to the trial the piston was 
 found to be leaking badly. The compression on this, as most other high-speed 
 
TWENTY YEARS WITH THE INDICATOR. 39 
 
 engines, is a considerable factor, much more than we should like to see. But 
 it is a part of the motion of the valve. If it opens early for the exhaust, it 
 must necessarily close very early, and as there is no limit of changing the 
 throw of the one witnout the other, then the whole matter has to be averaged. 
 The peculiar kink at the upper right-hand corner of each card shows the 
 action of this compression, and the opening of the valve. In one case the 
 steam line, properly speaking, is theoretically correct, with the exception that 
 it does not rise nearly as high as the steam pressure ; while, in the other case, 
 the valve does not open as it should, and the steam line falls away rapidly, 
 until the real point of cut-off is lost, and the line becomes very irregular on 
 the expansion curve. The back pressure amounts to but very little, indeed, 
 
 FIG. 16. 
 
 while the compression line, theoretically or mechanically, is quite too much, 
 and approximates to locomotive practice, where it is very necessary to bring 
 the reciprocating parts of the engine to perfect rest by a free use of steam. 
 The compression occurs here at about one-sixth of the stroke, or rather more 
 than that. The curve in this case includes the clearance, and is seen to be 
 materially above what was expected of it, approaching nearer the expansion 
 line at the point where expansion ceases. Taking the cut-off at the apparent 
 point, including clearance, it is .295 of the stroke. The feed- water consumed 
 during the trial was 40.78 pounds per hour. The power of this engine is 
 small. We have not all the facts in connection with it as to the effectiveness 
 of the boiler. It is only one instance of a pretty card in its general outline, 
 which, when it comes to be surrounded by the facts, makes a very expensive 
 
40 TWENTY YEARS WITH THE INDICATOR. 
 
 power. The action of the valve is such that it requires a large amount of 
 steam, and whatever the amount of leakage may have been, it was probably 
 not enough to radically increase the amount of steam used per hour. ; i ...- 
 
 FIG. 17. 
 
 LESSON VII. 
 
 THE originals from which the engravings were made for this lesson,, 
 sent us by a man, with the statement that he is a practical engineer, but/! not 
 an expert, and that he \g trying to learn something- by the practical applica- 
 tion of the Indicator to different Steam engines. He asked several questions, 
 and sent three sets of cards from two different engines. The cards contained 
 in themselves a whole lesson, and we propose to answer his questions from a 
 practical point of* view. 
 
 The diagrams (18 and 19) are taken from a Harris -Corliss engine, 36 X 
 14 inches, speed 65 revolutions, 55 pounds boiler pressure, 30 scale. Our 
 correspondent asks : " What are the reasons for the fluctuations shown by 
 the governor? I suppose, in figuring these, it would be proper to take ; the 
 mean. When the engine is loaded, the trips of the cut-off seem to act all 
 
TWENTY YEARS WITH THE INDICATOR. 41 
 
 right, but When she is not loaded, the fluctuations are very wide. What is the 
 reason ? 
 
 In the first place, these diagrams, for practical purposes, such as adjusting 
 the valves of an engine, or ascertaining the actual pressure of each end of the 
 cylinder, are absolutely worthless. They have no value whatever, and for this 
 reason : The diagrams, as shown here, are taken by a connection leading from 
 either end of the cylinder to the center of the cylinder, at which place a three- 
 way cock is probably used, and in the time required to change the three-way 
 cock from one side to the other, the load of 
 this engine may vary from 20 to 30 horse- 
 power. If the diagrams were taken as 
 quickly as possible, they cannot both be 
 taken upon the same stroke; consequently 
 the value of the comparison between the 
 different ends is lost. In the loaded engine 
 and the unloaded, the same readings are 
 apparent. We have drawn the atmospheric 
 lines ; and the lines, A B, upon each side of 
 the diagrams, are at exactly right angles to 
 the atmospheric line of the instrument. The 
 admission line upon one of these cards falls 
 away from the upright ; consequently the 
 induction valves, or steam valves, are too 
 late in their movements in opening. This 
 is applicable to each one of the four dia- 
 grams. It will be noticed that the crank 
 end, upon each set of cards, does not give 
 the same initial pressure as the head end, 
 and if Indicators were used upon each end of 
 the cylinder; this would undoubtedly be 
 found to be the fact in all the cards. The 
 reason for this is very apparent. The crank 
 end is much later in taking steam than the 
 head end. As the piston commences to 
 move away from the head of the cylinder 
 before the steam valve opens at all, and the 
 crank valve is much later in opening, with 
 reference to the motion of the piston, than 
 the head end, it never gets open wide 
 enough to admit the full pressure, from 
 
 FIG. 18. 
 
 the fact that the volume of the cylinder is 
 
 increased so much faster by the movement of the piston than the capacity of 
 
 the steam-port will supply. The head end, upon both diagrams, has several 
 
42 TWENTY YEARS WITH THE INDICATOR. 
 
 pounds more initial pressure than the crank end ; and although the head end 
 is late in the motions of the valve, the valve opens relatively sooner than in 
 the crank end. 
 
 The way of connecting the Indicator to the middle of the cylinder, 
 although altogether wrong, is the favorite method adopted by almost all the 
 
 high-speed engine builders, for it shows their line 
 of admission nearer to a right angle to the atmos- 
 pheric line of the instrument, and it is, therefore, a 
 point of advantage with them. They are obliged 
 to open their valves very quickly, or to use an enor- 
 mous amount of compression. The little amount 
 of time lost by the steam running the whole length 
 of this pipe, if only 12 inches, makes a certain cor- 
 rection, which is in their favor. On the Corliss 
 engine, as in this case, the admission of steam is 
 shown late upon the diagram, and, no doubt, if the 
 Indicator was connected by the shortest possible 
 connection to either end of the cylinder, this motion 
 would be somewhat diminished, but the essential 
 feature of the valves opening late would be found to 
 be a fact. 
 
 Our correspondent asks why the regulator fluc- 
 tuated more upon the crank end than upon the head 
 end. The reason is perfectly plain. When the 
 engine takes steam upon the head end of the piston, 
 it takes a larger amount than it can take upon the 
 crank. The tendency of this is to increase the 
 speed of the engine. While the piston is making 
 the stroke toward the crank end, the speed is some- 
 what accelerated, the regulator ball slightly raised, 
 and the crank end of the engine, when it takes 
 steam, is tripped just that amount shorter in order 
 to maintain the proper speed which the engine is 
 set to run at. Having taken this amount of steam, 
 the balls drop, and the head end trips longer. In 
 other words, the head end is doing considerable 
 more work than the crank end, and the crank end 
 is endeavoring to adjust all the time ; and if the 
 
 Indicators could be applied to both ends of the engine, and simultaneous 
 diagrams taken, there is hardly any doubt, in our mind, that the fluctua- 
 tion would be found as wide upon the head as they are shown upon the 
 crank end. This we have proven, over and over again in practice. One end 
 of the engine is doing more than the other, and the other end is trying all the 
 
TWENTY YEARS WITH THE INDICATOR. 43 
 
 time to strike an average and keep its speed; consequently the regulator 
 changes the point of cut-off at every single stroke of the engine. This is not 
 so apparent in the diagram taken with the whole load on, because the 
 percentage of variation is so very much less in proportion that it does not 
 show in the lines. 
 
 It would not be proper to take the mean of either one of these two 
 diagrams as the actual amount of work done. It would show, to be sure, 
 what was being done at the instant the diagrams were taken, but an average 
 of 36 upon one end and 16 upon the other, does not, by any means, give the 
 actual average of 26 horse-power as the work required to overcome the 
 resistance. If our engineer friend will throw away his three-way connection, 
 put it in the scrap -pile, and leave it there forever, make the shortest connec- 
 tion possible with each end of the cylinder, borrow an Indicator, if he does 
 not own two, and apply these Indicators to both ends of the engine, he will 
 find, we think, just what we have laid out for him. Then, if he finds the 
 admission line a little late, let him shorten up his connection until the angle of 
 the lines, A, B, and the admission line from the point of compression shall be 
 one line instead of two, get his engine so that it takes steam sharp upon the 
 center, not a particle before, then watch his engine for an hour, and when- 
 ever he changes the trip -dogs, changing both whenever he changes one, 
 putting one back and the other forward, figure his diagrams, and upon an 
 engine of this size he should not allow a variation of more than two or three 
 horse-power, taking care to adjust the engine as nearly as possible from the 
 full load ; he will then find, if he cuts the belt off his fly-wheel, that the engine 
 will cut off with the lightest load, both ends at the same stroke, and the variation 
 in the amount of work done should be, and will be, with proper adjustment, 
 very small indeed. He will find that his regulator will assume a very much 
 more settled condition it will not be reaching with every strrke. He will 
 find that the confusion of lines will disappear, and that this will not be all. 
 
 An engine of 150 horse-power was recently indicated by us at the request 
 of a party who was anxious to ascertain if the Indicator had any value. The 
 mean of the first diagrams, taken from simultaneous cards, showed 168 horse- 
 power. The head end was doing fully 15 per cent, more than the crank end. 
 After the engine had been adjusted, the mean of two cards was 154 horse- 
 power, with a variation of less than 4 horse-power as the mean of 1 2 sets of 
 simultaneous cards. The difference between 154 and 168 was being thrown 
 away ; in other words, the engine was requiring steam capable of maintaining 
 1 68 horse-power, when, as a matter of fact, the load only required 154 horse- 
 power. The speed of the readjusted engine was much nearer correct than 
 that of the engine, when one end was reaching after the other alternately. 
 
 There is a point here that engineers should understand, and that is, that 
 the variations of one end of the cylinder reaching after the other, when it is 
 not properly adjusted, calls for the use of more steam to do the same work. 
 
on 
 
 44 TWENTY YEARS WITH THE INDICATOR. 
 
 because it does not do its .work properly. The amount of coal require* , 
 this engine was 26 tons, before adjustment; after the adjustment, the patdes 
 reported that in the same length of time 20^ tons did all the work for three 
 
 successive weeks. The result of the mat- 
 ter has been, the party has ordered a pair 
 of Indicators, and his engineer is to make 
 himself familiar with them, and take dia- 
 grams every day. This is entirely a prac- 
 tical lesson, and there are hundreds of 
 engines running worse than this, which 
 are considered to be doing very well. 
 
 The diagrams 20 and 21 are from an 
 1 8 X 42 inch automatic cut-off engine, built 
 by Geo. A. Rollins & Co., Nashua, N. H., 
 with valves of the Corliss style, running- 
 72 revolutions per minute. The scale is 
 30, high pressure, the clearance being 2^ 
 per cent. The smaller diagrams, or the 
 lightest load, show that the head end is 
 doing the most work. The motion of the 
 valves is a little late upon each end, as 
 will be seen by reference to the upright 
 line. The crank end cuts off very sharp, 
 while the head end does more work than 
 the crank end. This is purely a question 
 of the adjustment of the valves. These 
 cards are very clean in the track of the 
 Indicator pencil. The card, with several 
 lines upon it, is from the same engine 
 under varying loads, and the lines of the 
 instrument have been traced as nearly as 
 possible. 
 
 In Fig. 21, A is the atmospheric line 
 of the instrument, the back pressure valve 
 being closed. This engine is in the Bay 
 State Sugar Refinery, Boston, and the vari- 
 ation in the lines is caused by the throwing off or on, two or three at a time, of the 
 centrifugal machines used in the works, which take from 25 to 50 horse-power 
 each to start. The engine carries steam the full length of the stroke, in an 
 almost absolutely straight line. This could not be done unless it had sufficient 
 valve-port room, while, in cutting off at nearly three-fourths of the stroke, or 
 at about one-half of the stroke, the lines are very good. The exhaust, in this 
 case, we cannot tell exactly about, as the back -pressure valve is closed. But 
 
TWENTY YEARS WITH THE INDICATOR. 45 
 
 it. is evident, from the general conformation of the three lines, that the exhaust 
 valve has a capacity nearly equal in exhausting to carrying steam almost the 
 full length of the stroke. When the centrifugal machines are thrown on, they 
 are required to be brought to speed as soon as a half minute, which makes a 
 very large change in the load of the engine, or the requirements. In this 
 
 case, however, the engine seems to be fully able 
 to answer these requirements, and the variation in 
 speed was very slight. But with carrying the 
 steam the whole length, it necessarily reduced the 
 speed of the engine somewhat, else the cut-off 
 would have acted. If anything, the exhaust 
 valves of this engine should open a little earlier 
 than they do. There is hardly compression 
 enough in it, and the lines of all three diagrams 
 which are traced, show that the exhaust is some- 
 what retarded at the commencement of the return 
 of the stroke of the piston. The opening of the 
 valves to admit steam is slightly late, only 
 slightly so, while the steam lines are most 
 excellently well produced. The outline of B, 
 Fig. 21, shows that the exhaust line is almost as 
 perfect as the steam line of the largest figure 
 The turning of the instrument shows it slightly 
 rounded,- in other words, that there is a small 
 accumulation of steam in the way of retardation. 
 If the outlines are correctly traced in the figure 
 by the eye of the reader, these will be found to 
 increase as the load increases, by the carrying 
 of steam further on the stroke. In other respects, 
 the lines corroborate the outline, making a work- 
 ing which should be very satisfactory, both as 
 regards speed and economy. As a general rule, 
 engineers do not pay attention enough to what 
 seems to them trifling indications of variation. 
 Every retardation of the exhaust upon the small- 
 est diagram, is multiplied, as the amount of steam is let into the cylinder 
 to overcome an increased resistance ; and the little points should be carefully 
 attended to, in order that they shall not become serious ones with the increase 
 of the load. The cushioning, or compression, is quite too little upon this 
 engine, and if the amount of motion at the commencement of the exhaust is 
 put upon the end of the exhaust, or, in other words, if the exhaust is opened 
 earlier, it will close as much earlier as it is opened. You will therefore reduce 
 the back pressure at the commencement of the exhaust, and increase the 
 
46 TWENTY YEARS WITH THE INDICATOR. 
 
 amount of compression by the closing of the exhaust, both of which are 
 advantageous in economy, and are certainly advantageous to the gooa 
 working of the machine. In the smaller cards, or those which indicate the 
 smallest load, the amount of steam used by the head end is more "than that 
 used by the crank end. If this were balanced, the engine would work 
 smoother, and there is no difficulty in balancing it if you have Indicators and 
 a little patience. And the nearer right this can be done, the better production 
 will be obtained regularly from the engine. Little matters are the important 
 ones wherever steam power is used, and in no case is it more essentially 
 important than in noticing little variations by the Indicator, when it is applied. 
 The width of a pencil line upon the Indicator diagram does not appear to be 
 much. At the same time, it may be an important feature in determining 
 where the trouble lies, and should be watched very closely, and no changes 
 should be made without carefully considering whether everything is tight and 
 just right ; for the value of an Indicator diagram increases precisely in the 
 ratio that you give it care or attention in the manipulation, and valuable in 
 results only as you are accurate and correct in obtaining them. 
 
 LESSON VIII. 
 
 THE examples in this lesson answer an often repeated question, Are simul- 
 taneous diagrams of any especial value over those which are not simultaneous? 
 The diagrams which we represent are not simultaneous diagrams for the whole 
 set. Each pair of diagrams were taken at the same time, but not upon each 
 cylinder of the engine at the same time. There is, therefore, more variation 
 than there would be if they were simultaneous diagrams. But these diagrams 
 represent another important feature. They were taken from a Corliss engine 
 which has been in use nearly or quite seven years, the valves of which have 
 never been bored, turned, or changed. It is, therefore, a very fair expression 
 of the value of the Corliss engine, in reference to the valves remaining tight 
 while doing the constant regular work. 
 
 In the next lesson we shall produce diagrams from high-speed engines, 
 taken from both ends of a pair of engines, and from each one of the engines 
 
TWENTY YEARS WITH THE INDICATOR. 47 
 
 at the same instant of time. A comparison will aptly illustrate the value of 
 simultaneous diagrams, which are very much underestimated by engineers in 
 general, as well as by engine builders, and their men who set up and start 
 engines. 
 
 LESSON IX 
 
 THE diagrams, Figs. 22 and 23, are from the Social Mills, Woonsocket, 
 R. I. The cylinders are 30 X 72 inches, 48 revolutions per minute, with a 40 
 spring, working three-quarters condensing. The figures in each one of the 
 cards represent the area as measured by the planimeter. These figures may, 
 for comparison, be called horse-power; for, if reduced to horse-power, the 
 amounts would represent precisely the same ratio that these figures do. The 
 left-hand engine is doing the most work, as the cards are taken, if they were 
 simultaneous, but the load may have varied between them. The left-hand 
 machine works all condensing. The back end shows 490, the front end, 513; 
 while the right-hand back end condensing is 488, the right-hand front end 
 high pressure is 376. The right-hand engine is working with about the same 
 amount of cut-off, and the front end, high pressure, is doing almost the same 
 amount of work as the back end without the vacuum. This could be very 
 easily adjusted by the use of the Indicator, if it was desired so to do. Let it 
 carry steam a trifle longer and it would do as much as the back end ; but all 
 these points are practically those of fancy, with the average engineer, though 
 not in a practical sense fanciful points. 
 
 There are some especial features about these cards. The valve gear upon 
 this engine has not, perhaps, the same delicacy of adjustment as the motion 
 Mr. Corliss is now building ; therefore the toe of the vacuum is not so abrupt, 
 and the engine is not working with as much perfection as would be desirable 
 if the valve gear could work to an exact adjustment. We say exact adjust- 
 ment, for if an engine has been working several years, the valves seat them- 
 selves ; and if the throw or travel of the valves should be changed, the engine 
 would be apt to leak steam until the valve seated itself in its new position. 
 For this reason, the adjustment of the valves of an engine should be made not 
 
48 TWENTY YEARS WITH THE INDICATOR. 
 
 less than three or four times each year, as in that case the valve never becomes 
 seated so deep but that it will readily accommodate itself to its new position. 
 
 The admission line in all these cards is very nearly correct, we might 
 say, almost exact. The steam lines are a little broken at first, whether this is 
 in the faulty motion or not, we have no means of telling, but the admission 
 of steam is ample, although the line is somewhat ragged. The cut-off is well 
 defined in all the cards, although not as sharp as it would be in an engine that 
 
 had been recently overhauled; but 
 when we come to consider the fact 
 that the engine has been working 
 for seven years, without any tink- 
 ering, and that the theoretical curve 
 applied to these diagrams covers 
 92 per cent., we must admit that the 
 cards are very fine. The amount 
 of power involved is nearly one 
 thousand horses. This is one of 
 the engines reported upon at the 
 New England Cotton Manufactur- 
 ers' Association, in comparison, in 
 1880, and it was found producing 
 its work with 2.66 pounds of coal 
 per horse-power per hour, and is 
 now doing much better. 
 
 The expansion line of all these 
 diagrams is very good indeed. 
 The steam is well handled, and, 
 should the engine be improved a 
 little, with a valve gear such as is 
 now being put upon engines of this 
 size, there is no reason why the 
 amount of fuel consumed will not 
 be made smaller, and the working 
 of the engine more perfect. But 
 taking an engine, which has done 
 duty so long and so regularly, cov- 
 ering 92 per cent, of the theoreti- 
 cal, with an honest showing, 
 
 we must admit, at once, that although the outlines of the cards are not perfect, 
 they are very much nearer perfection than in some newly-built engines, where 
 not quite so much brains have been mixed in their care and management. 
 
 It is noticeable that the outlines of the four diagrams are almost exactly 
 identical; a slight leak, perhaps, in one, is almost the only change. The steam 
 
TWENTY YEARS WITH THE INDICATOR. 49 
 
 lines are very nearly the same, while the expansion lines vary but little. The 
 vacuum is very even, and very nearly alike upon the three-fourths which are 
 used condensing, and it is certainly 
 a credit to the engineer in being 
 able to show such a result after 
 nearly or quite seven years of un- 
 interrupted service. This engine 
 drives the mill by a gear balance 
 wheel. The boiler pressure is 
 from 85 to 90 pounds ; the tem- 
 perature of the hot well, as re- 
 corded, is 1 10, attaining nearly 28 
 inches of vacuum, even in August. 
 One of the most noticeable 
 features is that of 88 pounds of 
 steam, shown by the gauge, at the 
 time the cards were taken, 83 to 
 85 is shown by the Indicator. 
 This point is often ignored in 
 practice, but it is, nevertheless, 
 one of the most important prac- 
 tical ones. Steam made in the 
 boiler is of no more use, if it can- 
 not be used at full pressure in the 
 cylinder, than money in the bank 
 that cannot be used in the business 
 man's everyday affairs, with just 
 this difference : the steam costs 
 money to generate, and there is 
 no use to throttle it down by im- 
 perfectly made valves and ports, 
 and no use whatever in attempting IG * 23 ' 
 
 to preach economy where the construction of an engine is such as to preclude 
 the realization of boiler pressure in the cylinder. The actual vacuum shown 
 by the Indicator is almost twelve pounds, and varies but slightly upon the 
 three cards. These diagrams will bear careful inspection, and, although not 
 perfect, they are very much beyond the average, and far beyond the general 
 practice in steam engine working. The engineer of this concern believes in 
 the use of the Indicator, and makes a daily report to his agent, of the amount 
 of power, where it is being done, and how ; and we believe he must make a 
 pretty good annual return to the concern that employs him, by the use of good 
 judgment and skill in the manipulation of his Indicators, and engine. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 LESSON X. 
 
 IN this lesson we have another type of engine, and a different way of 
 
 working steam, by way of contrast. In this case we have the diagrams (Figs. 
 
 24 and 25) from both ends of each cylinder on a pair of horizontal engines, 
 
 all taken at the same instant of time, four 
 instruments being used. The engine in 
 question is a Buckeye engine, built at Sa- 
 lem, Ohio. It is 22 inches in diameter of 
 cylinder, 44 inches stroke, 90 revolutions 
 per minute, boiler pressure 85 pounds, 
 throttle valve wide open, scale of spring 
 40. These diagrams were taken for the 
 purpose of ascertaining the condition of 
 the engine, and the amount of power 
 transmitted. The figures show the num- 
 ber of horse-power. The right-hand en- 
 gine is doing the most work. The outlines 
 of the diagrams are peculiar to this type 
 of engine. The left-hand engine, head- 
 end, has 148^ horse-power; crank-end, 
 164 horse-power. The amount of steam 
 pressure shown, when the valve opens, is 
 66 pounds carried into the cylinder. The 
 dotted lines show the pressure realized as 
 66, while the fine dotted line above shows 
 the boiler pressure. The mean pressure 
 upon the piston in the diagram doing 164 
 horse-power, is 21.92 pounds. The engine 
 cuts off at about 8.8 inches, or, say one- 
 fifth of the stroke. The theoretical mean 
 pressure, from an initial pressure of 66 
 pounds, the ratio of expansion being five, 
 would be 22.01 ; while, if this engine used 
 the boiler pressure shown by the upper 
 line, only 6.3 inches of the cylinder would 
 
 be obliged to be filled with steam at each stroke, instead of 8.8 inches at a 
 
 lower pressure. 
 
 These diagrams are precisely as they were taken, and they are not by any 
 
 means the worst we have seen where engines did not approximate to the 
 
TWENTY YEARS WITH THE INDICATOR. 51 
 
 boiler pressure. It is a very general thing, indeed, not only for this build of 
 engine, but for many others, not to come within 15 to 25 pounds of the boiler 
 pressure ; and whoever makes steam, and only uses a proportion of it, throws 
 away a proportion of his coal, which bears a relative value between that which 
 is generated and that which is used. This engine is working under a back 
 pressure, so that we could not obtain precisely the data as to what did exhaust 
 with the pressure valve lifted. The compression upon this engine, as will be 
 seen by the little notch upon two of them, is considerable ; so much so that 
 the pressure falls back before the valve is opened. The steam line falls away 
 rapidly after the steam is admitted. The expansion curve is very good, but 
 no doubt the valves were leaking slightly, and perhaps some steam was blown 
 by the piston. These matters are of secondary importance, our object being 
 to instruct our readers, rather than to criticise, except so far that our readers 
 shall learn to read the diagrams as the result of cause. 
 
 Upon the right-hand engine, 166 and 171, the compression line will seem 
 to take a different shape, comparatively, from those of the left-hand engine, 
 
 FIG. 25. 
 
 the admission line commencing nearer the travel of the valve than it does 
 upon the left-hand engine, so that, instead of forming a hook, it forms a point 
 upon one side. This engine, like its fellow, shows a very rapid dropping off 
 of steam pressure after the steam valve commences to open to admit the 
 steam, and the piston to move away. This would raise the question in our 
 mind whether the supply ports were large enough to supply that volume of 
 cylinder with steam ; or, as is the case with most slide valves, the travel is so 
 much different from that of the rotary that, in order to be enabled to cut off, 
 the travel is short and the ports usually somewhat smaller than in the case of 
 valves of other forms. The back end of the left-hand engine is doing much 
 less work in proportion than the forward end, at least ten per cent, differ- 
 ence, doing nearly twenty per cent, less than the forward end of the right- 
 
52 TWENTY YEARS WITH THE INDICATOR. 
 
 hand engine. At the same time the steam is wire drawn worse, or it falls most 
 in pressure after being admitted to the cylinder. Each pair are given as they 
 were taken, those of the right-hand engine, and those of the left. The 
 difference between working 66 pounds 8.8 inches, and 85 pounds 6.3 inches, 
 amounts to 28.2 per cent., very nearly, as the 8.8 inches of the volume of the 
 cylinder, 22 inches in diameter, must be filled with steam, every stroke, to do 
 the amount of w r ork that 6.3 inches in* length of the same cylinder would do 
 if boiler pressure were admitted into the cylinder. Aside from this, the card 
 is a very well produced one, we mean aside from the fact of falling off in 
 boiler pressure, and the loss of effective pressure upon the head of the piston 
 after the steam -valve opens. These diagrams were taken by the writer from 
 the engine, and are a peculiarity of the type or figure produced. We do not 
 know of the economy of the engine, or what is being done by the coal, except 
 that it cannot be economical in comparison. 
 
 LESSON XI. 
 
 WE have, in this lesson (Figs. 26, 27 and 28), not only an interesting, but 
 an instructive subject. These diagrams were taken by the writer, from 
 machinery designed and built by George H. Corliss, to the order of the Com- 
 mittee of Improved Sewerage of the City of Boston. The engine is a double 
 cylinder, having a pair of beams, a cylinder attached to one end of each l>eam, 
 
 FIG. 26. 
 
 and the other end of the beam connected with a crank upon the fly-wheel 
 shaft. One of these cylinders carries steam at high pressure, which exhausts 
 into a receiver. The receiver extends from one cylinder to the other, and 
 supplies the low pressure cylinder. The diameter of the high pressure cylin- 
 der is 1 8 inches, that of the low pressure cylinder, 36 inches. Both cylinders 
 
TWENTY YEARS WITH THE INDICATOR. 53 
 
 have a stroke of 72 inches, and a speed of about 27^ revolutions, or a piston 
 speed of 330 feet. The pump cylinders are connected direct to the walking 
 beam, half-way between the trunnion bearing and the end of the beam, or the 
 point at which the steam cylinder connection is made at one end, and the crank 
 connection at the other, therefore the speed of the pump plungers per 
 minute is 165 feet of travel. The high pressure diagrams are taken with a 60 
 spring, by the Thompson Indicator, 
 built by the American Steam Gauge 
 Company; the low pressure, by 
 the same Indicator, with a 20 
 spring. The vacuum gauge showed 
 27 inches. The steam gauge showed 
 119 pounds, of which 112 pounds is 
 exerted on the piston. The high 
 pressure cylinder exhausts under a 
 pressure of 12 to 14 pounds, n to 
 12 pounds of which is utilized in the 
 low pressure cylinder. The instru- 
 ments were attached to the engine 
 about two o'clock in the afternoon. 
 The engine was neither stopped nor 
 adjusted for taking diagrams. The 
 diagrams were taken in the middle 
 of the day's work, without any no- 
 tice or preparation, and were not 
 out of our hands from the time we 
 took them from the instruments 
 until they went to the engraver. 
 
 This engine has an essentially 
 new arrangement for working the 
 valves. It has no compression 
 whatever upon either cylinder ; the 
 exhaust shows precisely what is 
 going on; the high pressure cyl- 
 inder has a slightly ragged steam 
 line; but the point of cut off is 
 very sharply defined, and the line 
 of expansion is almost theoretically 
 perfect. Another point is particu- 
 larly noticeable. The low pressure diagrams do not vary one ten-thousandth 
 of one inch in the area of the two diagrams, the planimeter reading of which 
 is given upon each diagram. The high pressure end varies but very slightly 
 when we come to consider the high pressure of the steam, being only two horse- 
 
54 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 power. The bottom of the high pressure cylinder, and both ends of the low 
 pressure cylinder, vary less than one-fourth of one horse-power. 
 
 These diagrams were taken at the same instant of time, and during the 
 same strokes of the engine. The outlines of the cards, aside from the 
 serrations in the steam line, are very perfect indeed. This engine is jack- 
 eted, and has produced the wonderful result of 1.37 pounds of coal per 
 indicated and developed horse-power per hour, using poor Cumberland coal 
 at that. The actual power of the four diagrams averaged is 235.73 horse- 
 power. The load in this case is very nearly con- 
 stant, and consisted in lifting water to a height of 
 47.3 feet. 
 
 The reading of the planimeter and the horse- 
 power are both given upon each of the diagrams, 
 and it will be an interesting study for those who 
 are versed in the use of steam, or those who are 
 used to reading the Indicator cards, to give these 
 some attention. Ninety-eight per cent, of the 
 boiler pressure is utilized in the high pressure 
 cylinder, and from 95 to 97^ per cent, of the 
 receiver pressure is utilized in the low pressure 
 engine. The vacuum attained is from 12% to 
 13 pounds, and the temperature was not below 
 70 F. when these diagrams were taken. The 
 action of the valves may be noticed particularly 
 by all lovers of a first-rate diagram. The corners 
 are as sharp and well defined as it is possible to 
 make them, and if the Indicator had not been an 
 almost completely perfect instrument it would not 
 have shown it as it has. The vacuum line of the 
 low pressure engine is particularly worthy of care- 
 ful consideration. The condenser takes hold 
 sharply and maintains its hold, making the corner 
 as sharp as can be. This is a truly remarkable 
 production. The lines upon the high pressure 
 engine show as perfect a working of steam as we 
 ever saw from any engine, while the production of 
 this engine in duty has surpassed that of any other 
 engine ever built, and tested at work, so far as we 
 are informed. 
 
 Diagram 27 is a pump card, taken directly from the pump, Thompson 
 Indicator, 20 spring. The head under which the instrument was at the time 
 was 47.3 feet. The dimension of the pump and its speed are given above. 
 The pressure upon the Indicator is that due to a head of water of that height 
 
 FIG. 28. 
 
TWENTY YEARS WITH THE INDICATOR. 55 
 
 The lines of the card indicate that the pump is filled and kept full by the action 
 of the piston or plunger. This card will also bear examination and compari- 
 son, and it must be further understood that this engine has not received any 
 special elaboration, but was built and running five months and three days from 
 the reception of the order. When the order was received, no drafts or pat- 
 terns were in existence, and the original working parts of the engine have 
 never been tampered with. The engine was not assembled until it was put 
 together out of doors ready to go to work, in such a position that it could 
 not be lined or leveled, except one part with another. The bearings for the 
 beams to work on are 54 feet above the level of the ground. When standing 
 upon the gallery, there is no jar or shock to the machine in its working at 
 fiill speed and under its full load, pumping twenty-five million gallons of 
 water 47.3 feet high. The performance of the engine, we believe, has never 
 been equaled in the world, or at least in engineering records. 
 
 The engine is at work at the Pettaconsett works of the Providence Water 
 Works, with a set of pumps entirely different from those which it was working 
 at the time of this test. The pumps which were first used were adapted and 
 constructed for pumping sewage, while the pumps which are now in operation 
 are of the same general construction, although different in shape, as those 
 which have done such economical work in the Pawtucket Water Works, and 
 the engine which was guaranteed by Mr. Corliss to develop 100,000,000 duty, 
 kas shown + ii3,cxx>,ooo in its test by the city engineer of Providence. 
 
 LESSON XII. 
 
 THE educated man, educated, we mean, in practice, and the practical 
 engineer will see, in examining the diagrams in this lesson (Figs. 29 and 30), 
 two of the most elegantly perfect steam engine diagrams that they have 
 ever laid eyes upon. These diagrams were taken from the Pawtucket (R. I.) 
 Water Works pumping engine, built by George H. Corliss, and which, up to 
 the time of the construction of the Boston sewage pumping engine, by Mr. 
 Corliss, had accomplished the largest duty in the lifting of water that had ever 
 been attained by any engine in actual operation, in a practical way, under 
 the control and daily management of the engineer in charge. 
 
5 6 TWENTY YEARS WITH THE INDICATOR. 
 
 A description of this engine will not be out of place. It is a compound 
 engine of the horizontal pattern. The high pressure cylinder, 15 inches in 
 diameter, 30 inches stroke ; the low pressure cylinder, 30 inches diameter, 30 
 inches stroke. The pumps are in a hollow casting, which serve also for a 
 pillow-block for the fly-wheel, which is mounted between the cylinders. The 
 pump is in the lower part of this pillow-block casting, and is attached directly 
 to the same rod that the piston is. The slides are in the rear of the pillow- 
 block, where it is connected with a peculiar rocker-motion, which is again con- 
 nected to the crank upon the fly-wheel shaft upon either side of the engine. 
 The diameter of the pump barrel is 15 inches, the diameter of the plunger is 
 10.52 inches. The diameter of the air-pump is 20 inches, length of stroke 7^ 
 inches. The suction and discharge pipes are 15 inches in diameter; the fly- 
 wheel is 1 8 inches in diameter. Three boilers are used, 14 feet high, 4 feet in 
 diameter, 48 tubes three inches in diameter, the fire-chamber being 40 inches 
 high. The grate surface is 19.63 square feet, the fire surface 560 square feet, 
 the average steam space 3^ to 4 feet, it is supposed that the steam space 
 
 FIG. 29. 
 
 means 3^ feet to 4 feet in height, of the boiler, the steam pressure, 125 
 pounds ; average water pressure, no pounds ; the head against the pump is 
 269.1 feet; displacement at one revolution, 5.6592 square feet. The test of 
 this engine for twelve days, running ten hours, and lying still fourteen hours, 
 gave 104,357,654 foot pounds for every one hundred pounds of coal. This 
 trial was made on August 6th, and the days following, in 1878. The engine 
 was started pumping February 2d, 1878, pumping directly into the pipes until 
 November 6th, 1878. After it was put in charge of the engineer, the duty for 
 the first year was 106,234,300 foot pounds on all fuel consumed in pumping. 
 
 One diagram shown is from the high pressure cylinder, 15 inches in 
 diameter, 30 inches stroke, 46 revolutions per minute, steam at 125 pounds, 
 scale 58. There is only one criticism to make upon this diagram. It is abso- 
 
TWENTY YEARS WITH THE INDICATOR. 57 
 
 lutely perfect. Taking the clearance of the engine, the expansion curve is so 
 nearly perfect that it is no use to express it in any other way. The steam line, 
 as well as tne admission line, are almost geometrical forms. The expansion 
 curve in this card is slightly better than that of the engine built for the Boston 
 Sewage Committee, mentioned in the preceding lesson, and the reason for this 
 may be found in the fact, probably, that the engine makes 46 strokes instead 
 of 27^. The other diagram is from the low pressure cylinder of the same 
 engine, 30 inches diameter, 30 inches stroke. The pressure from the high 
 pressure cylinder is almost entirely utilized in the low pressure. The vacuum 
 is as good as it can be in practice, approaching the theoretical very closely. 
 The condenser takes full hold very early in the stroke, and maintains an ele- 
 gant vacuum line until the valve closes. The difference between the high 
 pressure cylinder, and that of the imitators of Mr. Corliss is, that they cannot 
 obtain a steam line which amounts to boiler pressure. In this case, nearly the 
 entire boiler pressure is secured by the piston. The steam line falls one pound 
 
 FIG. 30. 
 
 before it is cut off. These diagrams were taken without any preparation. The 
 coal consumption was 1.8 pounds per horse-power per hour, and there have 
 been no repairs on the engine since it was started. It had done over five 
 years' work, of ten hours per day, at the time the diagrams were taken. 
 
 We have seen and taken thousands of diagrams in actual practice, and we 
 have yet to see one that approximates these in absolutely answering every 
 requirement of the engineer, and we believe it will be a long time before we 
 see another. The record of the engine has been that of a perfect working 
 machine, furnished within the time it was promised, at the price at which it 
 was engaged, and instead of doing 30 per cent, of the work that it was con- 
 tracted for, it did over 30 per cent, more work than Mr. Corliss guaranteed it 
 to do. 
 
 Diagrams may be taken almost absolutely perfect, and if engineers who 
 study these lessons with an eye to benefit themselves, can produce such dia- 
 
5 8 TWENTY YEARS WITH THE INDICATOR. 
 
 grams upon their cylinders in actual working, as that of the high pi essure 
 cylinder, they will not have to figure very largely upon coal ; and when their 
 engine is in condition to make these, they need not fear extensive bilk for 
 repairs. 
 
 LESSON XIII. 
 
 IN this lesson we have, for the moment, abandoned actual practice in 
 reading, for the best effect, and show matters which are occasionally found in 
 actual practice. Fig. 31 is a card taken from a Corliss engine, 20^6 inches 
 diameter, four feet stroke, 60 revolutions, 72 pounds boiler pressure, 30 spring. 
 This engine has received a great deal of attention from a number of parties. 
 There was known to be a fault existing, and yet the fault was not traced, and 
 
 FIG. 31. 
 
 the trouble was not remedied. The expansion line seems to be good, and the 
 atmospheric and exhaust lines fairly run into each other, so that no troubk 
 could exist in that region. There is no compression, but there is a curious 
 hump at A, which might occur from one of two things, but in this case it was 
 an anomaly. The cylinder head was taken off, and the full pressure of steam 
 on the steam valve showed that the valve did not leak ; consequently it was 
 not a leaky steam valve. The question then arose, Where was the trouble ? 
 
TWENTY YEARS WITH THE INDICATOR. 59 
 
 The engine was started again and, as we have stated, several engineers gave 
 up the problem, declaring that the engine was not properly constructed. Mr. 
 Mosman (now deceased), with the American Steam Gauge Company, was sent 
 to examine the engine, and it was a considerable problem to him, as well as 
 tedious. He made all the ordinary tests, found the valves tight, and then 
 began to use his judgment. Upon experimenting with the exhaust valve in 
 this end of the machine, it was found, after the engine had moved an inch 
 or two of the stroke, that the exhaust valve had been set so that it opened 
 upon the back side, and allowed the steam, or a portion of it at least, for two 
 or three inches of the stroke, to pass by. This was corrected, and the trouble 
 was at an end. And yet there are two or three engineers who declare that the 
 engine is not right, and cannot be made right, although it makes as handsome 
 a diagram as any Corliss engine that has been in use, and been taken good 
 care of. 1 1 was a very serious defect, and it was a puzzle. 
 
 FIG. 32. 
 
 Fig. 32 represents a not uncommonly found result. , In this case the 
 engine gets blamed for what the Indicator is at fault about. And yet the Indi- 
 cator, with which this was taken, was in the hands of an expert. The cut off 
 is very near the point, A, and the dotted line, and would extend above the 
 line as shown by the dotted line, but in this case the instrument leaks, the 
 piston and the cylinder both being worn, we mean the piston and cylinder of 
 the Indicator, hence, in this case, the Indicator is very unreliable. This can 
 be ascertained fully by actual tests, and whoever reads this diagram, and is 
 posted in his business, would find, upon applying the expansion curve, that 
 the point of cut off was very much shorter than that shown in the card. This 
 case was also handed over to our friend Mosman, and the Indicator was after- 
 wards reorganized. 
 
 Fig. 33 is another case of a most peculiar diagram. The admission line is 
 straight, the engine taking steam like a hurricane, but the piston Indicator 
 drops from the point, A, to that of B, in precisely the same way that it comes 
 
6o TWENTY YEARS WITH THE INDICATOR. 
 
 up on the admission line. This line is not due to the action of the engine, but 
 the piston, or the cylinder, or both, were grooved, the steam being shot into 
 it, the piston moving at a good speed. When the Indicator commences to 
 descend, it goes out of all semblance of real expansion, because the steam 
 shoots through the grooves until it partially seats itself again, when the vibra- 
 tion makes the little notch in the expansion line. All these are matters which 
 can only be learned by practical demonstration, and this is a most peculiar 
 case, yet it is not the only one we have ever seen. An Indicator, to be relia- 
 ble, must have a considerable amount of attention paid to it. The engineer 
 must know how to apply tests for correctness, and he must know how to read 
 the lines which he gets, and know what is possible to be made by his careless- 
 ness, or lack of attention, in applying his motion, as well as in seeing that his 
 instrument is in perfect order. 
 
 The effect of either one of the illustrations which we have given, if a man 
 were ignorant at all of the true reading of the lines, would be to go on with 
 
 FIG. 33. 
 
 poor work, condemning the engine for what, in two of the cases, is clearly the 
 fault of the instrument, and, in Fig. 31, a lack of brains in whoever attempted 
 any such mal-adjustment ; but there are certain engineers who run by the rule 
 of thumb, and it proves a very expensive rule to run by for the man who pays 
 for the coal. If a man has no care for the interests of his employers, he is the 
 last man in the world to have the handling of an Indicator or the running of 
 a steam engine. 
 
 These three illustrations make one of the most interesting lessons which we 
 have given. They are from positive fact, in actual practice. In every case the 
 information which they embody has been most dearly bought by the parties 
 who were paying for the fuel which was run through the engines in question. 
 
TWENTY YEARS WITH THE INDICATOR. 61 
 
 If an engineer will pay attention to these lines, and remember how they can 
 be caused, he will then, whenever a difficult or seemingly uncommon card is 
 presented for him to read, remember, from his own experience, or from his 
 reading, if he observes and remembers, that certain matters will cause 
 certain results, and he will be enabled to judge of the probability of these 
 without experimenting at the expense of his employer. A man to be 
 successful with the Indicator must be one who reasons, and applies the 
 somewhat uncommon rule of common sense ; and the man who has the most 
 common sense is the man who oftenest succeeds in obtaining excellent results 
 from the proper use of his instrument. 
 
 LESSON XIV. 
 
 IT is frequently stated that the Indicator is of very little use, except for 
 the careful noting of results, or for the following out of doctrines or theories 
 which relate, more particularly, to expert tests. This assertion is as void of 
 truth, and is as far from the fact, as it is possible to put any given number of 
 words into a sentence attempting to mean something, and yet make a signal 
 failure of it. 
 
 Fig. 34 is a curious figure to be described by an instrument. This was 
 taken from a 250 horse-power engine, made by Charles S. Brown, of Fitch- 
 burg, but Mr. Brown, in his adjustment of the engine, did not make any such 
 card as this. One of those men who know everything but one, and who never 
 use the Indicator, a man who was able to set the valves of an engine by the 
 marks, or by gauges, or measures, or by guess, or something else, made his 
 arrangemenents upon this engine, and when he got the machine in such a 
 condition that it would not run with much more than half its usual load, he 
 concluded that the engine was not worth anything ; and the owners of the 
 
62 TWENTY YEARS WITH THE INDICATOR. 
 
 engine concluded that they must find somebody who could tell tnem whether 
 the engine was good, bad, or indifferent. The diagram in question was one 
 of the first ones taken after the adjustment of the instrument, and it fully illus- 
 trates the folly or foolishness, to use a plainer word of a man in attempting 
 to tinker with the valves of an engine. In this case the exhaust valve closes 
 at A, while the stroke ends at B. Compression takes place, which carries 
 the piston of the Indicator to C, when it follows the outer line back to D, as 
 the piston starts on its return stroke. At this point, rather late in the day, the 
 steam valve opens ; but, as a stern chase is always a long one, the engine gets 
 steam all the way, from D to E, as the motion of the 
 piston is shown by the leaning line from D to E, and 
 the pressure cannot be brought up fully, because 
 the piston is moving, and requires a very large 
 amount of steam, in order to fill the volume of the 
 cylinder from B to D, which could not be filled until 
 after the valve opened at D. From E to F, the steam 
 line is short, where the cut off takes place. The ex- 
 pansion line is eood. the exhaust line is first-rate, but 
 the line, E, G, B, D, C, simply represents lost work 
 or steam used after it could be useful, or of any effect. 
 The area of these figures is respectively 194 effective, 
 and 70 absolutely lost or thrown away. Undoubt- 
 edly, if the steam had been properly applied, 210 to 
 220 would have expressed the whole area ; but, in this 
 case, one-third of the steam used is absolutely thrown 
 away. This is an interesting study to show what can 
 be done by these men, and we believe there are less 
 of them than ten years ago, who can set an engine 
 by their ear, or by marks, and it will be a caution to 
 those among our readers who have the good sense to 
 let alone matters which they cannot be positively sure 
 of. After the engine was properly adjusted, there was 
 no more doubt as to whether Mr. Brown's work was 
 or was not up to his ordinary standard. 
 
 Fig. 35 represents, truthfully, only the proportion 
 that is being done by the different ends of the engine. 
 The little hooks at A, and the badly formed lines, B, 
 are due to the inferiority of the instrument, which 
 was in very bad order. In this case the instrument 
 leaked. When the compression was made, before 
 
 the valve opened, the steam came through the instrument to a certain extent 
 so that the piston, by the action of the spring, dropped, making this hook. 
 There is no point of cut off upon the one. Upon the other, the cut off if 
 
TWENTY YEARS WITH THE INDICATOR. 63 
 
 squarer, but, at the same time, it falls like a brick. Very little need be said of 
 these diagrams, except to show that an instrument, which is not properly 
 
 FIG. 35. 
 
 adjusted, or which is not as it should be, may mislead a man very seriously in 
 getting at the effective value of the work being produced. 
 
 LESSON XV. 
 
 THE diagrams in the present lesson are of more than passing interest, and 
 were taken from the engine of a man who places no value on the Indicator. 
 It is only necessary to say that the diagrams were only taken when he found 
 that something was the matter, which his engineer could not manage; and 
 this is only one of numerous practical applications of the value of the Indi- 
 cator, which the expert in its use is continually meeting. The engine in 
 question is a Harris-Corliss, 14 inches diameter of cylinder, 42 inches length 
 of stroke, 60 revolutions per minute, the pressure in the boiler varying from 
 65 to 75 pounds. The diagrams, Figs. 36 and 37, are from the different ends 
 of the engine, 37 being the crank end, and 36 the head end. Fig. 37 is one of 
 those peculiar looking ones which we frequently meet with in actual practice, 
 more especially from engineers who know exactly how to set their valves by a 
 scratch or prick punch mark; and they can tell exactly how "she takes 
 steam " by watching the cut-off slide. The engineer, in this case, simply had 
 to give it up, and if he had gone a few steps further, his engine would have 
 run the other way. Fig. 36 shows three lines, as they were taken from 
 
64 TWENTY YEARS WITH THE INDICATOR. 
 
 the instrument, and they are most wretchedly irregular lines too. The steam 
 line is as full of humps as a camel's back, and the notches and irregularities 
 are the exact counterpart of the movements or action of the steam, as it is 
 admitted to the cylinder. The admission line, in itself, is very late. The 
 steam valve commences to open only after the piston has commenced its 
 stroke. It does not open fully until after the piston has traveled several 
 
 inches. The exhaust will be seen to be very late, 
 upon both diagrams, Figs. 36 and 37. It is com- 
 paratively small in its showing upon Fig. 36, from 
 the fact that it shows a very much lighter load 
 than that of Fig. 37. The amount of power, 
 32.4 horse-power, given on Fig. 36, is the 
 mean of three lines, the largest amount being 
 plus 50 and the smallest only 22. Fig. 37 
 has the same general outline as Fig. 36, but 
 in this case Fig. 36 was set to cut off at less 
 distance than Fig. 37, so that Fig. 37 is only 
 a single line, and is doing three-quarters the 
 work of the engine. The line, in the case of 
 Fig. 37, is very bad indeed. The valve does not 
 commence to open until after the piston has 
 started on its return stroke. The cut off is very 
 badly defined, and might lead to the idea that the 
 valves were leaking badly, but no experienced 
 engineer would try to ascertain this question 
 until the valves were in proper position. The 
 toe at the end of the expansion, at the commence- 
 ment of the exhaust line, is an additional amount 
 of work thrown away. 
 
 This is only a fair specimen of the way that 
 many engineers get their valves, and they are 
 always found in the hands of those people who 
 do not use the Indicator, and who frequently 
 make the assertion that they do not believe in the 
 Indicator, for it is of no use. All such are per- 
 fectly welcome to their belief, and their employers 
 FIG - 36 ' sometimes change their minds when the engine 
 
 has been properly indicated and adjusted by those who do believe in the 
 Indicator, and who know how to apply it and read properly its results. 
 
 C and D (Fig. 38) are from the very same engine, after the Indicator had 
 been properly applied, and the needed corrections made in the motion of the 
 valves. The horse-power is almost identically the same in both, the fractions 
 being very small. The compression is, almost to a unit, the same. The 
 
TWENTY YEARS WITH THE INDICA TOR. 65 
 
 admission line is lost in the proper compression, and the steam line is carried 
 as straight as a line can be. The line of expansion shows very little loss, and 
 the diagram, taken altogether, is a very good production. It is needless to 
 say that a very considerable saving of fuel resulted as the difference between 
 the engineer's setting, Figs. 36 and 37, and the man who applied the Indi- 
 cator in Fig. 38. These diagrams are from actual practice, and were given us 
 
 FIG. 37. FIG. 38. 
 
 by the late Mr. Mosman, of the American Steam Gauge Company. They 
 were taken with 40 springs, and the engine at its regular work. Probably the 
 question never entered the head of the engineer in charge, as to the result of 
 the use of steam, as in the diagrams, Figs. 36 and 37. The steam in Fig. 36 is 
 admitted, in all sorts of quantity, in the endeavor of the regulator to reach 
 after and equalize the load, which is done in the other end of the cvlinder; but 
 
66 TWENTY YEARS WITH THE INDICATOR. 
 
 as the cut-off slides are set, in Fig. 38, to cut off longer than is necessary, and in 
 Fig. 36 are set shorter than they should be, it is simply impossible for the regu- 
 lator to adjust the difference between them ; for the difference is so great that 
 the regulator cannot measure it by the differential strokes of the cut-off slides, 
 or the motion which is given them through the change of position of the balls 
 on the governor. In this case the crank end of the engine is doing more than 
 double that of the head end, and these motions of the head end are shown in 
 the irregular steam lines by its race after the other end of the engine ; and 
 exactly in proportion as these lines differ from each other was the resistance 
 or the strain upon the different parts of the engine, differing at each end of the 
 stroke, making 120 times per minute. In other words, the engine jumps 120 
 times a minute after its load, and the regulator is simply unable to adjust the 
 difference; or, in other words, is attempting to accomplish an impossibility. 
 The engine in this case is using something like forty per cent, or more steam 
 than would be necessary, when properly adjusted, as is seen in Figs. 37 
 and 38. This is only another important lesson that people can learn if they 
 will, but usually only learn when they are obliged to. It is all the more to the 
 credit of the Indicator that it is able to show up, in the hands of an experienced 
 manipulator, these points where pocket value is the result attained ; and in a 
 case like this, the amount of coal burned, before and after adjustment, is a 
 factor that can always be measured in dollars and cents. This is the standard 
 of too many steam users in quite an opposite direction. 
 
 LESSON XVI. 
 
 IN this lesson we have a decided difference in engineering practice, and 
 upon one of the points which we have dwelt in previous lessons, and which 
 will be distinctly exemplified by the comparison between the cards. It refers 
 to the realization of the boiler pressure of the cylinder. The diagrams, A, B 
 (Fig. 39), were sent us by a correspondent, with the following data : Buckeye 
 engine, 14 X 28, 40 scale, 70 pounds steam, 112 revolutions. Diagrams taken 
 with one instrument standing in the middle of the cylinder, which, we suppose, 
 means taken with a three-way cock. A is the crank end of the engine ; B is 
 the head end. The figures 102 and 116 represent respectively the area of the 
 
TWENTY YEARS WITH THE INDICATOR. 67 
 
 diagram, as measured by the planimeter. C, C, represents, by the little white 
 line above the letter, the 70 pounds boiler pressure. D represents the atmos- 
 pheric line of the instrument. Our correspondent writes : " My vacuum gauge 
 reads 25 inches, while the vacuum on the instrument only shows four pounds, 
 or eight inches." He further writes : " Will you please give me some informa- 
 tion in regard to setting the valves ? " 
 
 We cannot give any information regarding the setting of the valves from 
 the diagrams given. The engine appears to be working free, and really it is 
 the best pair of Buckeye diagrams we ever saw taken from actual practice, we 
 mean the outline and apparent action of the valve. In taking diagrams with 
 the three-way cock, where there is any variation in the load, it is absolutely 
 impossible to balance, as we term it, each end of the cylinder, and have one do 
 the same amount of work as the other on its return stroke. If both of these 
 diagrams had been taken upon the same stroke of the engine, with two instru- 
 ments, one upon either end, we should say, by all odds, to set the valve so 
 
 FIG. 39. 
 
 that the crank would not be cut off quite so soon. The particular feature 
 about these cards is one which we generally find on this kind of an engine 
 it fails to utilize the full amount of the boiler pressure. In another set of cards, 
 sent by the same party, from the same engine, and doing much more load, the 
 head end measures 227, and the crank end 194 on the planimeter. In this 
 case, quite a considerable difference is therefore indicated in horse-power, the 
 head end, as is generally the case, doing the most work. Taking the pressure 
 of the steam and the point of cut off, this diagram approaches the theoretical 
 curve in a very practical degree. 
 
 The diagrams, C, D (Fig. 40), were taken from a Harris -Corliss engine, 
 36 X 14 inches, in the Massachusetts Charitable Mechanic Association build- 
 ing, at the exhibition of 1881 ; 75 revolutions, 40 spring, boiler pressure 85 
 pounds, the steam was carried some distance, gauge on the pipe 82 pounds. 
 The Thompson Indicator was applied by Mr. Mosman for the American Steam 
 
68 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 Gauge Company. The initial pressure, as the Indicator records it, is 78.5 
 pounds. These diagrams were taken by a three-way cock, but under radically 
 different circumstances from those which are shown by the diagram in Fig. 
 40. The engine had no connection with any machinery in the building, 
 except the dynamo machines for the electric lights. The engine regulated in 
 the very best possible manner, the variation in speed was almost nothing, being 
 run, therefore, with as constant a load as it was possible to attach to it, diagrams 
 being taken by turning the cock. Probably one was taken upon one stroke of 
 the engine, and the other not missing more than one or two strokes, while the 
 load, at the same time, is shown by twelve pairs of diagrams, which we have, 
 and which varied much less than one horse-power in twelve sets. One end 
 reads 420 on the planimeter, and the other 417. This is a result that is very 
 seldom obtained in practice, and in this case it was undoubtedly effected by 
 good judgment and careful adjustment by the parties in charge of the engine. 
 
 C D/ 
 
 \ MP 87. 1 96 / 
 
 FIG. 40. 
 
 In this case it will be seen that almost ninety-six per cent, of the steam pipe 
 pressure is actually shown by the piston of the Indicator and its pencil attach- 
 ment. Two cases could hardly show more completely the difference in the 
 practice of two engine builders. The Harris-Corliss engine was making 450 
 feet piston speed per minute. This result shows that the Indicator is reliable, 
 when in practical hands, to a nicety that was hardly credited to it a few years 
 since, even by men of experience and who should have had confidence in their 
 own opinions. And yet there are men who call themselves engineers, who 
 attempt to belittle the results of the Indicator's reading, or practical applica- 
 tion. But one thing is certain engine builders are coming to place more 
 and more reliance upon the application of the Indicator in practical hands ; 
 and a man who has any breadth of practice with the Indicator can demonstrate 
 to the absolute satisfaction of any party who knows enough to know the 
 difference between twelve tons of coal a day and fifteen tons of coal a day, that 
 the man who sets by marks or spots, prick punches, or the end of his 
 
TWENTY YEARS WITH THE INDICATOR 69 
 
 thumb, may work a week upon an engine in setting the valves, and the prac- 
 tical application of the Indicator will demonstrate that in this way the valves 
 of any good engine could not be set within a row of apple trees of right, and 
 apple trees are usually not nearer than twenty feet apart. 
 
 LESSON XVII. 
 
 THE cards in this lesson are from actual practice, by an engineer who 
 seems to know something about the Indicator, and that it is something more 
 than a curiosity or a plaything. They were sent us by a correspondent, who 
 asked several questions. Fig. 41 is a diagram from a modern built engine, with 
 so-called Greene cut-off. The party running this engine supposed he had 
 arrived at the limit of its power. After the valves had been adjusted, twenty 
 pounds less boiler pressure were used, with a very great saving in fuel. The 
 size of this engine is 12 inches diameter, 36 inches stroke, 50 revolutions per 
 minute, boiler pressure 55 pounds, scale 40. Our correspondent stated that 
 the valves were left, by the man who- put them in, so that they produced this 
 diagram. This is rather a curious looking figure, yet, by no means, an 
 uncommon one. B shows the boiler pressure, and what would have been the 
 admission line, if the valves had been in order. The valves do not fully open, 
 so as to admit any approximation to the boiler pressure, until after the piston 
 has traveled more than one-fifth of its stroke. We should judge from its 
 length, after it gets a steam line, that the engine was heavily loaded for its 
 capacity, although little can be told as to the load which the engine is really 
 doing from such an outrageous outline as this. The steam is carried for a 
 large proportion of the stroke, the expansion line is irregular, the exhaust 
 valve only partially opens at C, while, if it opened as it should, it would com- 
 mence at D, and make the line, D, E. In this case the exhaust, valve really 
 opens at C, and the piston returns some distance before the steam is freely 
 exhausted. For some reason we cannot see why there seems to be a small 
 amount of compressed steam at E. When the piston starts upon its return 
 stroke, the piston of the Indicator drops, and the under portion of the loop is 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 formed. After the piston has returned upon its stroke, and the lines cross 
 each other, the steam valve seems to open but slightly, and the admission line 
 commences at F. The engine works under a small amount of back pressure, 
 
 and makes a very poor use of the steam which 
 is fed to it from the boiler ; and if our correspon- 
 dent had sent us a card showing the engine cor- 
 rectly working with approximately the same load 
 and the same amount of steam, it would have 
 been an easy matter to have told him what the 
 loss was in this card, which cannot now be told. 
 It is only an illustration of how badly an engine 
 will work when it is not properly taken care of. 
 
 Fig. 42 is a diagram from the same correspon- 
 dent, from a full stroke engine, doing from 12 to 18 
 horse-power, and using coal enough to run forty 
 horse-power with any kind of decent usage. The 
 cylinder was 18 inches in diameter, stroke 12 
 inches, 100 revolutions per minute, boiler pressure 
 60 pounds, scale 40, vertical engine. While this 
 is an old-fashioned engine, and we may expect 
 old-fashioned practice, it has some peculiarities of 
 its own not at all in its favor. A represents the 
 line of boiler pressure ; B, the admission line ; C, 
 the steam line ; D, the line of curiosity ; E, getting 
 ready to exhaust ; F, the exhaust valve opens ; G, 
 the atmospheric line of the instrument. The line 
 of curiosity, as we have expressed it, is really 
 the pressure in the cylinder increased after the 
 expansion has taken place. This very seldom 
 occurs in well constructed engines. When, in all 
 probability, all the steam had been given which 
 was required, the engine was a double port 
 one, and after the valve had made its travel, the 
 ports were temporarily opened during the last of 
 the stroke of the piston ; therefore the piston of the 
 Indicator was raised by the admission of more 
 steam, or the governor opened the valve from a 
 changed speed. Not knowing the real construction of the engine, this is only a 
 guess, but it is one of the things sometimes found in actual practice. In any 
 event, the exhaust of this engine is about as poor as it can be. The valve 
 opens very slightly at E, commences to open thoroughly between E and F, 
 and gets open so as to reduce the pressure in the cylinder just before it closes 
 for the admission line, B. We do not wonder that our correspondent felt 
 
 FIG. 41. 
 
TWENTY YEARS WITH THE INDICATOR. 71 
 
 curious, for he has really struck the old curiosity shop in Indicator diagrams ; 
 but, stranger than his personal adventure, is the fact that men are still found 
 who do and will use engines making just these same botch- work diagrams. 
 There can hardly be two instances where steam is worse misused than in the 
 
 FIG. 42. 
 
 two diagrams shown. Fig. 41 is entirely the fault of the operator; Fig, 
 42 is really without any remedy, except to put the engine into the old scrap 
 pile, where it ought to have been put years ago, if fuel is of any account. 
 
 LESSON XVIII 
 
 IN this lesson we have some peculiar looking diagrams, and they are also 
 peculiar in another sense peculiarly wasteful. They seem to be lacking in 
 every respect where economy has any claim, and yet the engines from which 
 these diagrams were taken are in use, and undoubtedly the men who are using 
 them consider that they have a pretty good arrangement for a steam engine. 
 The diagram (Fig. 43) really required considerable study on our part to ascer- 
 tain which end up it was ; and we only found, after corresponding, that the 
 party who sent it to us was not joking; he only sent it as a curiosity, some- 
 thing which he picked up in actual practice, no longer ago than June, 1881. 
 The data, which comes with it, is as follows : Diameter of cylinder, 1 2 inches ; 
 length of stroke, 24 inches ; revolutions per minute, 85 ; boiler pressure, 75 
 pounds; scale, 20. As this has a throttle regulator, there is, of course, no 
 approximation to the boiler pressure ; the actual realized pressure on impact 
 is from 35 to 36 pounds. The engine would seem to take its steam early 
 enough, but its carrying line, or steam line proper, has a variety of contortions 
 
72 TWENTY YEARS WITH THE INDICATOR. 
 
 in it which have no significance, no economy, do not approximate to good 
 practice, and are all as nearly bad as need be. The commencement of the 
 exhaust, at C, is the commencement of a struggle. The engine, as we have 
 mentioned before, takes steam at about 35 pounds ; when the exhaust valve 
 commences to open at C, the engine commences to exhaust under precisely 
 30 pounds back pressure. After one-half of the cylinder has been exhausted, 
 we still find 14 pounds of back pressure on the line, D, and at the termination 
 of the back pressure, or when the valve closes,. we still find 8*4 pounds at E, 
 the area of the figure, by the Indicator, showing that the power exerted is 295, 
 while the area of the figure between the diagram proper and the line of rest 
 of the instrument, or the real atmospheric line, has an area of 229. In other 
 words, if this engine were doing 295 horse-power by the steam which is used, 
 it would be working under a back pressure of 229 horse-power ; and if the 
 back pressure were only a little larger, it might be a question whether the 
 
 FIG. 43. 
 
 engine would run at all, or if it would not start and run the other way. We 
 believe that there are not many such engines as this in use at least, we 
 should hope not. But it is only a question. No doubt the man who con- 
 structed this engine had in his mind a good working one, and that he made 
 the ports and the travel of the valves, and the lap and the lead, and all those 
 things, just as nearly right as he could. Probably the introduction of the 
 Indicator would somewhat, at first, surprise the man running the engine ; but 
 if he could not read the lines to see what was doing inside the cylinder, he 
 could evidently understand, if fuel was of any value at all, after having these 
 lines explained to him, that one-half the fuel which he burned was a little 
 worse than thrown away, in fact, he was burning two pounds and twenty- 
 nine hundredths to put a brake on to the two and ninety-five hundredths 
 which did the work, whereas, had this engine been making use of its steam 
 at the same pressure, so that the valves would have exhausted properly, instead 
 
TWJ^NTY YEARS WITH THE INDICATOR. 73 
 
 of having 295 horse-power of work, and 229 horse-power of back pressure, 
 the outline of a figure, constructed to properly take charge of the steam, would 
 yield 426 horse-power ; hence, here is a waste almost equal to one-half of the 
 fuel, and, at the same time, only a trifle more than one-half of the proper load 
 which the engine should do, is being yielded. Twice two being four, the 
 engine is using four times the amount of fuel it should do to develop the load 
 which the Indicator shows is being done. Aside from the fact that some men 
 still exist who do not think the Indicator has fulfilled its mission, or that a man 
 can set the valves of his engine by his eye or ear, jack-knife or rule, this dia- 
 gram would not be worth the space it occupies. 
 
 In Fig. 44, we have another style of engine, a different style of diagram, 
 a radically different result, but the same principles are embodied, and 
 although not to quite so great an extent in percentage, the result of loss is 
 much larger than in the small engine. This diagram was taken in a saw-mill, 
 
 FIG. 44. 
 
 in the northern part of Michigan. We have frequently read that a saw -mill 
 was a rough place, but we did not suppose they would work steam on exactly 
 this kind of a scale. The data, which comes with this diagram, is as follows : 
 Cylinder, 28 X 28 inches ; 100 revolutions per minute ; boiler pressure, 105 
 pounds; scale, 40; the ports, 2 inches by 18, for steam ; exhaust ports, 3^ by 
 [8 inches ; lap on each end of the valve, |f. This is rather a peculiar shaped 
 diagram. The dotted line, A, is the initial pressure, 80 pounds ; the regulator, 
 therefore, stifles the engine from 25 pounds of working pressure. The steam 
 ports of this engine seem to be, for their size and stroke, nearer the correct 
 area than the exhaust ports, the difference in pressure in the length of the 
 stroke, at the point B, is only 12 pounds, the engine, therefore, loses but 12 
 pounds in carrying steam seven-eighths of the stroke from the initial 
 pressure, the initial pressure being 80, and the pressure, at the moment the 
 steam valve closes, 68 pounds. This engine, in common with many others of 
 
74 TWENTY YEARS WITH THE INDICATOR. 
 
 the slide valve type, is late in the motions of its exhaust. The exhaust valve 
 opens, or commences to open, rather, just above the letter C, and here we have 
 35 pounds back pressure as the piston starts on its return stroke. The exhaust 
 is never allowed to touch the atmospheric line of the instrument, E. At D, 
 the back pressure will be seen to have increased, the smallest amount of back 
 pressure being three pounds, about what we might expect in a well regulated 
 engine of the family from which this one came. At D, the pressure increased 
 to nearly nine pounds, and the exhaust valve seems to have closed. At a 
 point above D, not very well denned, the steam valve seems to have opened, 
 but the pressure is not sufficient to carry the piston of the Indicator up so but 
 that the line leans away from the vertical line, showing that the steam line 
 opens a trifle late. This is a general analysis of this diagram. 
 
 The planimeter says that the area of Fig. 44, as described by the Indi- 
 cator, is 600 ; it also says that the area of the figure which bounds the back 
 pressure is 125. Here we have 600 units of work and 125 units of worthless- 
 ness in back pressure, or about six times that which should be allowed in an 
 engine of this type when in good condition. This engine probably never did 
 exhaust correctly, and without some change, which cannot be determined 
 without further data, it never will. If the exhaust port of this engine is 3^ 
 X 1 8 inches, the party who made the examination should have ascertained 
 whether the same area as the 2X18 was not in some way mixed up with thus 
 3fij X 1 8. He also asks the question, What would be the effect of attaching 
 a condenser to this engine ? 
 
 Briefly, if the exhaust valves of this engine will not open better than they do 
 now, the condenser will not have a chance to make much, if any, of a vacuum. 
 If, by changing your exhaust arrangements, you can make the exhaust valve 
 open at B, on the upper line, without making it close enough quicker at D to 
 lose by enormous compression what you would gain by early release, then your 
 condenser may possibly effect a great deal of help to the engine. If a saw-mill 
 can afford to run an engine under these circumstances, by burning sawdust, 
 slabs, or that sort of trash, they may be able to make lumber ; but an engine 
 of that kind, working at that rate of expense for fuel, anywhere in this country 
 where coal had to be used, would ruin any concern with a hundred thousand 
 dollars capital, in less than five years, if all the rest of the branches of their 
 business were well managed. 
 
 These diagrams are two of the worst instances of the use of steam that 
 have ever come to the eyes of the writer. They are neither uncommon in 
 their outline, nor in the fact that such diagrams can be produced, almost any 
 day, without going ten miles from Boston. Men are running engines which 
 should have been in the scrap pile years ago, but the fact of it is they have 
 some cut-off arrangement, some safety -stop arrangement, possibly their son 
 has invented something which has been attached to it, or they bought it sec- 
 ond-hand, and bought it cheap. It would pay the users of either one of these 
 
TWENTY YEARS WITH THE INDICATOR. 75 
 
 engines to buy a strictly first-class engine of double the capacity of either one 
 of these, run in debt for it, pay ten per cent, a year interest, and in five years 
 they would have the engine paid for, and more than have saved its cost in fuel 
 and in production. An engine that is overloaded in this condition can never 
 do its work right or regularly, and any little laying on of the last straw will 
 break the camel's back entirely, that is, reduce the speed so that it does not 
 work up as it should. It is a little curious that so many men pay no attention 
 to this very important element in our manufacturing establishments. A very 
 little difference in a mill of a thousand looms makes a good profit on a mill 
 of three or five hundred looms ; if the looms all lose a pick a minute, in a 
 thousand loom mill, on 64 X 64 goods, it makes nine pieces a day, or 2,700 
 pieces per year ; and the fact of the matter is, we have seen mills of this size 
 which varied from 5/^2 to 7 strokes on the engine in a minute, and so on all 
 through the day, making a difference of several thousand pieces of cloth in a 
 year. 
 
 LESSON XIX 
 
 WE received an invitation from an engineer friend to visit, with him, a 
 large manufacturing establishment, in which he would show us something good. 
 The time was set, and we gave him an hour's leeway to get ready this exhibi- 
 tion, before appearing on the scene. After waiting for some fifteen or twenty 
 minutes, while his Indicators were attached, he showed us something good ; it 
 was something wonderful, at least not very good, and we rather imagine 
 he was slightly non-plused himself when he came to show us the original of 
 which Fig. 45 is as near an exact reproduction as we can make it. The data, 
 which goes with this, is as follows: Corliss engine, 30^ inches diameter, 36 
 inches stroke, revolutions from 88 to 90, 32 spring ; boiler pressure, at the 
 time this particular diagram was taken, 70 pounds ; duty, rolling wire ; high 
 pressure. A condenser was attached, but was not working at the time this was 
 taken. 
 
 Here are two very peculiar outlines, and all the more peculiar because of 
 the complaints which our friend had received that the engine worked hard. 
 We should rather think it did work hard. H and C are respectively head and 
 crank ends. The engine is a trunk lighthouse, cylinder at the top, crank at the 
 
76 TWENTY YEARS WITH THE INDICATOR, 
 
 bottom, driving a large fly-wheel, from which a 3O-inch belt conveyed the 
 power. The lines, E, are at right angles with the atmospheric line of the 
 instrument, and were the basis of the adjustments which followed. These are 
 drawn, in order to show whether the engine is early or late in taking steam. 
 The same letter refers to the same lines upon all the diagrams. After the 
 diagrams in Fig. 45 had been taken, the question then became of consequence 
 what to do with the engine. It will be seen that the admission line upon the 
 head end is late, in fact, very late indeed ; so late that, out of 70 pounds 
 boiler pressure, only 28 pounds are admitted. While on the crank end, the 
 Indicator has attempted to draw a map, and after progressing for about three 
 or four inches of the stroke, 28 pounds boiler pressure are utilized. The 
 crank end is doing nearly, if not quite, double that which the head or upper 
 end is. There is an approximate cushion upon diagrams at B, but it amounts 
 to nothing practically. 
 
 FIG. 45. 
 
 In order to get through with the thing at the earliest moment, we sug- 
 gested some changes, which were promptly made by the gentleman in charge, 
 while our friend took the diagrams. After making two or three changes, the 
 figures shown at B were the result. In this case, however, it will be seen that, 
 while more steam enters the cylinder, the motion of the valves was still very 
 far behind. Having adjusted the cut-off so that the two ends were approxi- 
 mately correct, or balanced one with the other, and, having used all the leeway 
 upon the rod stems, or connections, which we dared to, the load remaining the 
 same all the way through, we then had recourse to the eccentric, sliding it over 
 on the shaft an inch or more. From this we obtained diagrhms C, Fig. 47, 
 which are vastly different looking from those of diagrams A, Fig. 45. All this 
 was done within an hour, starting and stopping not less than four or five times. 
 We do not know precisely the estimation in which the gentleman in charge of 
 this engine holds the Indicator, but these three plates, which form the subject 
 of our lesson, show the difference between an engine which does its work very 
 hard, and the same engine given a fair chance to do its work easy. In Fig. 45 
 we have 28 pounds of the boiler pressure admitted into the cylinder. In 
 
TWENTY YEARS WITH THE INDICATOR. 77 
 
 Fig". 46 we have 40 pounds admitted into the cylinder. In Fig. 47 we have 52 
 pounds ; therefore, by simply changing the position of the valves, double the 
 steam is admitted into Fig. 47 that was admitted in Fig. 45, and we doubt if 
 tnere are many cleaner cards found, than those in Fig. 47 ; whether the engines 
 are in cotton mills or rolling mills is not a matter of any consequence. 
 
 The cushion lines, B, in Fig. 47, conform very nearly to our own ideas of 
 the proper amount of cushion for an engine, simply enough to relieve the jar 
 or shock, and it makes little difference what the amount of load is, the cushion 
 does not increase with the load in the Corliss engine, or in any engine built 
 with the Corliss valve. This is a point which slide-valve makers do not 
 exactly appreciate. If there is any use of the Indicator at all, there is no 
 instance in which its value can be any clearer shown than in this particular 
 case. Here is an engine doing regular work, in which we presume the load is 
 varied from 15 to 25 horse-power, sometimes between the very stroke of the 
 piston up and down, and that a hundred horse-power variation can be made in 
 less than one-half of one minute when it is doing its regular work. 
 
 FIG. 46. 
 
 If there is anything in the use of steam, the diagrams A, Fig. 45, show an 
 extraordinarily bad working of steam ; diagrams B, Fig. 46, show a desirable 
 improvement, and diagrams C, Fig. 47, show a great deal better work than 
 either of the others ; and yet this is the very same engine, the same valves, 
 the same load, the same speed, the same steam boilers, and only an hour's 
 difference from the time of taking the diagrams, and no expense beyond 
 that of simply changing the nuts, and running the rods out or in, as was nec- 
 essary to bring about the adjustment; and yet, if this engine is doing 300 
 horse-power per day, and it does do more than that, using three pounds 
 of r uel per hour, actually costing $4 per ton, the difference between the actual 
 result in using the valves as we found them, in Fig. 45, or using them as we- 
 1'eft them in Fig. 47, would be a trifle over $12 per day. Yet there are some 
 'nor in the world who are so wise that they consider that the Indicator has 
 
;8 TWENTY YEARS WITH THE INDICATOR. 
 
 outlived its days of usefulness, and that, while it is a very pretty toy, " it don't 
 amount to much in practice/' 
 
 As it may interest some of our readers to ascertain how these changes 
 were made, we shall take Fig. 45 for our first analysis. If you refer to the 
 letters B, in the corners where the line of compression should be, you will find 
 that there is hardly an outline of compression in either one. The amount of 
 steam which is compressed is very slight. Rising above where the compres- 
 sion line strikes the admission line, following upward on the line E, you will 
 find that the admission line gradually leaves the line E, more and more, as it 
 approaches where the steam should be cut off. And the reason for this is very 
 plain. The steam valves are terribly late. The exhaust valve on the head 
 end opens earlier than it really needs to. It does not open as early in Fig. 47 
 as in Fig. 45, from the fact that it was set back by the connection. Now > 
 
 FIG. 47. 
 
 the question is simply, What is needed to be done? The straggling line 
 on the crank end, which is marked C', simply means that the valve opens 
 very slightly \ the piston moves along a little, and the valve opens more, which 
 makes the line D ; when the piston arrives at F, the valve commences to open 
 still more, and finally it gets wide open after the piston has proceeded so far 
 in its stroke as G, all these letters referring to diagrams A, Fig. 45. Now, 
 it will be seen that this carries steam clear over to H' before it is cut off; while 
 on the other end it is simply guess-work to tell where the cut off comes. Now 
 B, upon each of the diagrams A, Fig. 45, requires to close the exhaust valve 
 earlier ; D, F, G requires to open the crank valve very much sooner ; while H , 
 as compared with H", is much longer than H". Then we must open the crank 
 valve much sooner than before ; we must lengthen the cut-off dog so that the 
 crank end will cut off much shorter, and we must shorten the head cut-off dog 
 so that it will not cut off so soon. Now, the exact quantity of movement to 
 
TWENTY YEARS WITH THE INDICATOR. 79 
 
 be given any one of these several alterations is a matter of judgment, no 
 man can say a sixteenth of an inch, an eighth of an inch, two turns, or three 
 times round, but we must always proceed with caution. Diagrams B, Fig. 
 46, show what resulted from it. It will be seen in C, that the compression at 
 B has increased ; that instead of D, F, G, H, in diagrams A, Fig. 45, we have 
 a very fair admission line at D, and D', but that both these motions are still 
 late, as compared with the line E. The cut off is much nearer balanced, 
 although the head end does not get quite as much steam as the crank end, C. 
 We have now approached the limit of safety in running the connecting rods 
 out of the nuts and connections, and it does not do to go too far in this direc- 
 tion. If now we compare the diagrams B, Fig. 46, with those of diagrams A, 
 Fig. 45, we notice, in general, that the motions are much nearer uniform 
 that is, both ends than they were before. Now, there is only one question 
 remaining: Having "balanced up," as we term it, the various motions, take 
 the eccentric and roll it forward on the shaft, say an inch, for a guess. This is 
 a quantity which can only be measured by the lines drawn upon the Indicator. 
 Fig. 47 shows what the result of this movement was. In this case, it will be 
 seen that we have very nearly "balanced up," although the head end cuts off a 
 little sharper than the crank end. The expansion lines are approximately well 
 disposed to each other, while the compression at B is just about right for a 200 
 horse-power engine. Now, there seems to be a question as to the right amount 
 of compression, or cushion, as it is termed. We have therefore drawn in a 
 dotted line to show the square-cornered diagram, which so many people 
 admire. The only difference between the line, B, which is the actual line of 
 the instrument, and the dotted line, is, that in the line, B, the exhaust valve is 
 completely closed at D, and the piston of the Indicator gradually rises to 
 about the point E', thus making 24 pounds pressure. This pressure does not 
 cost anything, it simply confines so much steam, which would otherwise 
 be exhausted, but it does accomplish a very useful effect in allowing 
 the piston-head to cushion upon 24 pounds pressure, and gradually bring 
 itself to rest, while, if the dotted line was followed, the exhaust valve would 
 not close until D'. In this case, there is nothing left for the piston to cushion 
 against, and the whole arrangement would go a half inch further if the 
 connection would let it ; consequently there is that peculiar chuckling noise, 
 which is frequently called pounding, and, in reality, it is a species of 
 pounding, and sometimes it pounds the keys off in the cross-head, and the 
 cylinder head comes off. In other words, the line, B, by closing the valve at 
 D, produces a compression, and it eases the piston and all the connections 
 back to the crank in coming to the dead center, or line of rest. Then, if the 
 steam valve opens properly, these two lines, compression and admission, merge 
 into one another, so that only an experienced man can tell precisely where the 
 blending occurs ; and just so much steam as is used by this proper compres- 
 sion is anabsolute savingof money to whoever pays the bill. If fuel is of any 
 
8o TWENTY YEARS WITH THE INDICATOR. 
 
 value, the parties who are running this engine will have made a simple saving 
 of more than $2,000 a year, in difference between Fig. 45 and Fig. 47, if they 
 will only take as good care of their engine as the diagram C, Fig. 47, will 
 produce by the fuel. 
 
 These diagrams are not perfect, for the engine has been in use for a 
 number of years, and they are only given for the purpose of imparting infor- 
 mation from actual practice. 
 
 LESSON XX. 
 
 WE frequently receive requests to show the exact difference between a 
 perfect or theoretical use of steam and the actual or accomplished use in 
 diagrams. There are so many ways of constructing a hyperbolic curve, that 
 it is well not to confuse those readers who are so much interested in learning 
 it, and, at the same time, the process and the tools or instruments required, 
 must be confined to something that does not entail expense upon them. For 
 this purpose we have selected and engraved a method which is very nearly 
 accurate, sufficiently so for all practical purposes. This method was orig- 
 inated by Prof. John Pierce, of Providence, R. I., twenty years ago. 
 
 G, A, equals the clearance in the engine, and in this our readers must not 
 make any mistake ; the clearance of the engine is not in proportion by 
 measurement between the piston head and the cylinder head which is given 
 in this engraving in any well constructed engine; and, in figuring the 
 clearance of the engine, the steam and exhaust ports must be figured from the 
 bore of the cylinder back to the face of the valve, in cubic inches. The 
 amount of these two calculations must be reduced to so many inches of an 
 increase or extension of the bore of the cylinder ; for instance, if we have a 
 26-inch cylinder, and we find that an aggregate of the steam and exhaust 
 ports added to the clearance between the piston when at full stroke, and the 
 piston head, amounts to 265 inches, it is equivalent to one-half inch of an 
 extended bore of the cylinder ; so, if it amounts to 530 inches, it is equivalent 
 to one inch added to the bore of the cylinder. This is how we obtain the 
 line, G A. 
 
TWENTY YEARS WITH THE INDICATOR. 81 
 
 A B represents that portion of the stroke which steam was carried ; B 
 represents the point of cut off proper ; A C represents the whole length of 
 the travel of the piston. Now the line, G C, represents the length of travel . 
 and the clearance included; A F equals the steam pressure realized in the 
 cylinder ;AF GH BE = CD. To the line, A F, before we com- 
 mence to erect the perpendiculars, we add 14.7 'pounds for the pressure of the 
 atmosphere, so that we should have said A F represents the boiler pressure 
 and the atmospheric pressure added thereto ; so that CD, BE, A F, G H, 
 are all one and the same thing, the boiler pressure and the atmospheric 
 pressure, making the absolute pressure. Now, develop B C into any number 
 of points that is desired, preferably making them repetitions of the distance 
 A B, numbering them i, 2, 3, 4, join each of these and the point C with H, 
 the joining lines intersect B E in the points A, B, C, D, E ; then draw the lines, 
 i, 2, 3, 4 parallel to B E, and at right angles to B C, to intersect the former 
 series of lines, H i, H 2, H 3, H 4, H C. Now, from the line, B E, starting 
 at A, draw a line at right angles to B E, and strike the first upright i ; wherever 
 
 FIG. 48. 
 
 the line A strikes the line i at right angles to B E, that is, where the line of 
 the expansion curve, or hyperbolic curve, should pass through that point. 
 We have now the line, A F ; draw the line, B G, from B E to 2 ; then the line, 
 C H, from B E to 3, and the line, D I, from B E to 4, and the line, E K, from 
 B E to C D. The points then given, F, G, H, I, K, are a properly constructed 
 hyperbolic curve, which is approximately correct, for the line of expansion of 
 steam, according to Mariotte's law. Now, all this can be laid out with a pair 
 of steel triangles, taking one having a six-inch leg, and its fellow may be 
 perhaps a four-inch leg for the long legs. 
 
 This is one method of laying out the hyperbolic curve. We shall, in a 
 future lesson, show how some particular engine builders take, perhaps, a little 
 liberty with mathematics or geometry, or may be with facts, in describing the 
 line of cut off, to satisfy their ideas of working steam expansively. The method 
 we have eiven is not, by any means, the best for laying out the curve, but it is 
 
82 TWENTY YEARS WITH THE INDICATOR. 
 
 a simple one, it is approximately correct, and it is one that all our engineers 
 can understand. In our next lesson, we shall show another way, which is 
 . really simpler than this, but this embodies the principles so well that it will be 
 well for those following up these lessons to take a few cards, where the point 
 of cut off is well defined, and experiment with them. Now, it frequently occurs 
 that an engineer wishes to test this and not allow other people to know that 
 he has been doing it. In that case, let him take his Indicator diagram, and a 
 piece of tracing paper ; then fasten the tracing paper over the diagram and do 
 all his work with a lead pencil upon the tracing paper, having put a small tack, 
 or a drawing tack, through each end, or through two corners, so that he 
 can compare the lines without making the least mark upon his Indicator 
 diagram. He can then, after having completed the demonstration, draw, 
 with a steady hand, the expansion or actual line of the engine in a different 
 colored pencil, or by dotted line, and he will then have the whole thing, so 
 that he can hand over the card to some of his better educated friends, perhaps, 
 and let them try their hands on the same diagram. 
 
 LESSON XXL 
 
 IN this lesson we give another method of laying out the hyperbolic curve 
 and where the point of cut off is clearly defined. This method is simple and 
 accurate, and can be done upon any Indicator diagram in a few moments' 
 time, with a pair of dividers, a pencil, and a short, straight edge. In 
 Fig. 49, G H B E, and both lines equal the pressure upon the piston, with 
 14.7 added for the atmospheric pressure ; hence the line, B E, equals the boiler 
 pressure and atmospheric pressure combined. G B is the length which the 
 steam is carried, B being the point of cut off. On the lower line, H E G B, 
 and 8, i=HE, i,2 = Ei, etc. Divide the distance from E to 4, or from B 
 to the end of the diagram, into equal distances, which are the repetition of 
 the distances, G B, and H E, and from the point, B, draw a line to figure 2, 
 and the point at which this line intersects the ordinate i is the point through 
 which the hyperbolic curve will pass. From B, through the ordinate 2, draw 
 a line to the point 3, and so on, drawing the line B 2, B 3, B 4, B 5, or what- 
 ever the number of points may be. The line joins the base line, H 5, one 
 point further from B than the line through which it passes. Whatever the 
 
TWENTY YEARS WITH THE INDICATOR. 83 
 
 point of cut off may be upon any diagram, leave as many spaces and one 
 more as the length of the diagram covers. Then draw the lines from the 
 point of cut off, B, through each one of the ordinates, to the foot of the next 
 ordinate beyond, whether it be five lines or nine lines ; then, by means of a 
 curve, or the dividers, draw the hyperbolic curve through, and you have one 
 of the best arrangements for the delineation of the actual line of expansion 
 that we know of. This method, like the one in the previous lesson, was 
 originated by Prof. Pierce, of Providence, R. I. 
 
 Fig. 50 is one of the nearest approximations to a perfect Indicator card 
 that we have ever seen. The data, which comes with this, is as follows : 
 Rollins engine, built by G. A. Rollins & Co., of Nashua, N. H. ; Corliss type, 
 24 inches diameter, 42 inches stroke, speed 75 revolutions per minute, boiler 
 pressure 75 pounds, scale 40; new engine, in the Cleveland Rubber Com- 
 pany's factory, Cleveland, Ohio ; 74/^ pounds of the boiler pressure realized 
 in the cylinder. The engraving is an exact fac simile of the card which came 
 
 FIG. 49. 
 
 from the Indicator, and was not a tracing. The steam line is perfectly elegant, 
 and is as straight as we ever saw. The expansion line has a little variation, 
 which is no doubt caused by the instrument. The exhaust line is as nearly 
 perfect as the steam line; the slight amount of compression shows a very 
 finely working exhaust valve, while the admission line is just as nearly right 
 as it can be. This is simply an elegant Indicator card from actual practice^ 
 and leaves very little to be desired. Those of our engineers who are running 
 Corliss engines, and are practicing with the Indicator, may imitate this card as 
 near as they can, and may rest assured that when they reproduce it they are 
 doing as near the best of anything possible as they will ever do. Every 
 motion of the valve is smooth and clear, and some of our beginners will do 
 well to take this as a model to apply the curve to, by either of the methods 
 given in this or the previous lesson, and figure up the percentage. In this 
 engine, no excess of compression or cushioning is used, steam is given at the 
 right place and at the right time, the corners are perfectly sharp and clear,and 
 
8 4 TWENTY YEARS WITH THE INDICATOR. 
 
 very well defined; and, when we say it is one of the handsomest specimens of a 
 card or diagram from actual practice, we merely tell the whole story, and state 
 a fact. Messrs. Rollins & Co. are to be congratulated; and we know that 
 Mr. Rollins himself is a close student of the Indicator, and a man who profits 
 
 FIG 50. 
 
 by his experience with it. While we do not know the fact in this relation, 
 we have no doubt that he has profited by the practical application of the Indi- 
 cator in the perfection which he has attained in the handling of his steam and 
 exhaust valves. 
 
 LESSON XXII. 
 
 THIS lesson illustrates another instance of experimenting. The diagrams in 
 question areour own, taken from an engine having a Corliss cylinder 16 inches 
 diameter, 42 inches length of stroke, intended to be run at 55 revolutions, 
 with comparatively little regulation, steam pressure 6c; rounds, scale 30. 
 
 The diagram, H R, Fig. 51, is from the head end of the cylinder, as we 
 found it working, and presents some peculiar characteristics. The admission 
 line is a peculiarly lazy one, and the serration at A, it will be seen, is repeated 
 four times distinctly before the steam line, B,is really commenced. When the 
 steam line is finally started at B, it will be found to be one-sixth of the whole 
 stroke before the steam valve becomes completely open. The steam line is 
 
TWENTY YEARS WITH THE INDICATOR. 85 
 
 then maintained very well; but with steam 65 pounds in the boiler, there is 
 only 52 pounds on the piston This is entirely too much of a difference. If 
 it was two or three pounds, or five pounds even, upon this size of an engine, 
 and at this speed, it would not be so very considerable. If it were a five or 
 
 FIG. 51- FIG. 52. 
 
 six hundrerl horse-power engine, and the difference was seven or eight 
 pounds, we should not think so much about it on account of the volume 
 of steam, as in this case, where the volume is so small, and the engine is 
 situated so near the boilers. It will be noticed that the admission line 
 leans very much too far away from the upright we have erected. 
 
86 TWENTY YEARS WITH THE INDICATOR. 
 
 Leaving the connection of the steam line with the cut off at C, we ha\ e 
 the expansion line, C C D, with some peculiar looking steps in it. Exactly 
 what causes these steps is, to a certain extent, conjecture in any ordinary 
 engine. In this, there is no conjecture about it; the engine is badly regulated, 
 and is jumping about ; the load is variable, and we should not be surprised 
 even to find saw teeth all the way down the length of the expansion curve. 
 In fact, the serrations are visible far below the second C. This is caused by 
 the very unequal action of the regulator in giving different impulse to the 
 piston, and by the peculiar action of the ever-varying load. 
 
 At D we commence to exhaust. Curiously, the piston of the Indicator is 
 held up for one-twelfth of the stroke, and a pressure, at D E, of 12 pounds, is 
 exerted against the piston. Ordinarily we might ask, Why was this peculiar 
 point? In this case it is easily explained. This engine the dimensions 
 already given is expected to exhaust through a five-inch exhaust pipe, 
 while it is fed through a five-inch pipe and a six-inch valve, as though the 
 valve could increase the capacity of receiving steam from the boiler which was 
 throttled in a five-inch pipe. When the exhaust commences at D, there is 
 twelve pounds back pressure between D and E, E representing the termination 
 of the atmospheric line of instrument. After the steam is started to exhaust, 
 all men, who are conversant with it, know that a current of steam will soon aid 
 essentially in relieving the pressure; hence, it requires one-twelfth of the 
 stroke to establish this current in the exhaust pipe. It commences to decrease 
 the pressure at F, and from there to the end of the stroke, or at G, the back 
 pressure is gradually reduced, in no case being less than three pounds. There 
 is a certain way out of this in the proper adjusting of the valves. Its mate, 
 diagram H S, Fig. 56, was taken from the same end of the same engine, and 
 shows what improvement can be made by even a little adjustment ; and, for 
 the sake of relieving the exhaust pipe, the load was very materially reduced in 
 this diagram, to ascertain whether the engine would exhaust freely with a 
 lighter load or not. 
 
 This is a very practical illustration of what may be accomplished in an 
 hour's time by the proper application of the Indicator. It will be seen that 
 the Indicator will not increase the amount of steam drawn through a too small 
 pipe, nor will it make less steam than is actually present. The diagram, H S, 
 Fig. 52, shows how the steam can be admitted properly, so far as the capacity 
 of the valve motion and valves will admit. C C, in the diagram H S, 
 shows us conclusively that there is a little lost motion probably in the valve 
 in the stem. 
 
 Time was not allowed for a full bringing up to the standard of this engine, 
 as the question was between the builder and purchaser as to whether it was in 
 good condition ; and, until further changes are made in the work, it is impos- 
 sible to bring it up to standard. The lesson, however, is instructive to those 
 who are watching these points, and if any of our readers desire to apply the 
 
TWENTY YEARS WITH THE INDICATOR. 87 
 
 hyperbolic curve, erect the upright in the same scale precisely to the extent of 
 65 pounds ; take the same point of cut off, carry their expansion line out, and 
 see what the actual percentage of the work done by this engine is, with the 
 steam that should be in the cylinder if the pipes had been properly connected, 
 and the valves had done their work. If any of them try this, they will be 
 astonished, and it will be an interesting and instructive example. 
 
 LESSON XXIII. 
 
 WE have something in this lesson of more than ordinary interest, and 
 from which we can learn something in reference to real economy. The card, 
 W C, Fig. 53, came from a reliable party, and was taken from an engine built 
 some years since to do 350 horse-power. The dimensions and data are as 
 follows : Cylinder 28 inches diameter, 5 feet stroke, 50 revolutions, steam -pipe 
 
 FIG. 53. 
 
 6 inches diameter, exhaust-pipe 7 inches diameter, steam ports 24^6 inches 
 area, exhaust ports 24.5 inches area, balanced poppet valve and automatic cut- 
 off, scale 30; steam pressure 50 pounds, which is one of the most peculiar 
 features of the whole diagram. The line, E, in the diagram, W C, Fig. 53, is 
 
88 TWENTY YEARS WITH THE INDICATOR. 
 
 the line of rest of the instrument, or the atmospheric line of rest ; the dotted 
 line, A, is the line of steam pressure. We have assumed, in our calculation, 
 that the engine should have carried steam on the dotted line, A, instead of 
 which, when it cuts off at B, it has fallen 15 pounds from boiler pressure. The 
 dotted line shows the expansion curve had the engine cut off at boiler pressure. 
 It will be seen that the steam line is quick rather than late in its movement, 
 and that, when the valve is open, the steam pressure is maintained for so brief 
 a period of time that it makes simply a point. The steam, therefore, com- 
 mences instantly to fall away from the boiler pressure, and, as the piston 
 commences to travel away, its motion is slightly increased, and the boiler 
 pressure falls correspondingly. On being cut off, at B, the real line of the 
 engine is found at C, and without going into the niceties, its approximation to 
 the real theoretical curve below would lead us to infer, and with very good 
 reason, that the valves, after closing, were not tight, or that some re-evapora- 
 tion took place. When the exhaust valve does open, and the vacuum line, D, 
 is made, the condenser, when it gets hold, only gives us two pounds, or four 
 inches ; after traveling one foot we have four pounds, in the middle of the 
 stroke we have five pounds, and at the heel of the exhaust we have six pounds, 
 or twelve inches, as the largest amount of vacuum obtained. The line, F, is 
 the line of absolute vacuum, or 14.7 pounds ; it will be seen that we do not, in 
 the largest measure accomplished, quite reach one-half of the vacuum, which 
 we should have done. There are two points about this diagram which abso- 
 lutely corroborate what we shall find if we turn to the area of the steam ports 
 and exhaust ports, and that is, that they are both insufficient to do the amount 
 required with that size cylinder and that size engine. The steam ports are 
 shown, conclusively, to be very lame in their dimensions, by the instantaneous 
 falling off of the boiler pressure, the moment the valve is opened and the 
 cylinder begins to travel ; cutting off, at about one-quarter the stroke, we lose 
 15 pounds boiler pressure, and when the exhaust valve opens, for the con- 
 denser to operate, we get 2, 4, 6 pounds vacuum, instead of 8, 10, 12. These 
 two things show conclusively, therefore, that this engine never was fit to run 
 with economy at that speed ; it might have done very well at one-half the 
 speed, or perhaps 30 to 35 revolutions. The party who sent it wrote as 
 follows : " The engine was unable to perform the 350 horse -power with any 
 sort of economy, and came near ruining the parties by reason of their very 
 large coal bills and irregular speed." 
 
 In another engine of the same general type, we have the diagrams C C, 
 Fig. 54, from a Wright engine, thirteen years in use, with 22 inch cylinder, 42 
 inch stroke, 63^ revolutions, scale of 40 pounds, boiler pressure 78 pounds, 
 non-condensing. The diagram, which we reproduce, is one of a pair upon the 
 same card, and shows 52^ pounds of steam at the moment of impact, or at 
 A. The dotted line, B, represents the realized pressure. This engine carries 
 its pressure to the point of cut off with a loss of only three pounds. The 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 89 
 
 expansion line is very good ; the exhaust valve opens and closes well, and the 
 difference between the exhaust line and the atmospheric line, of 2^ pounds, is 
 partially caused by using steam for heating. If we were running this engine, 
 we should open the exhaust valve quicker, so as to avoid the initial back 
 pressure on the dotted line, C, and to try and open it more in the line of D. 
 This would probably give us a little more compression, which would be all the 
 more favorable, as shown at E, and would relieve the engine, so far as it can 
 be relieved from its peculiarities of make. Evidently, this engine has been in 
 the hands of parties who have taken good care of it, else it would never have 
 made thirteen years' time, showing such good lines as it does. The most 
 serious fault about it is, its lack of realizing the boiler pressure ; whether it is 
 
 FIG. 54. 
 
 caused by pipes we cannot say, not having that data given, and there is not in 
 this diagram anything to show that the steam passages and exhaust passages 
 are stifled, as in its fellow, Fig. 53. 
 
 The difference between these two engines is, simply and purely, that C C^ 
 Fig. 54, will do much more work with the same fuel than W C, Fig. 53. 
 Whether C C, Fig. 54, could be improved by increasing the size of the steam 
 pipe and exhaust pipe, we do not know. These diagrams are from actual 
 practice, and are all the more interesting because they are so ; both are from 
 the same type of engine generally, although some differences exist, and the 
 point is conclusively shown that, if one is faulty, there is no reason that the 
 other need be, or for any real cause on account of the system adopted. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 LESSON XXIV. 
 
 IN this lesson we have diagrams taken from condensing engines from two 
 different builders. The differences in practice, in the condensing engines, are 
 quite as radical as in the high pressure or non -condensing engines, both as to 
 valve gear movements, and control of the valves, regulation, and the vacuum ; 
 and, as the vacuum is the important part of the condensing engine, we have 
 chosen engines which are not fitted with any of the patent condensers, or the 
 portable or attachable condensers, whatever they may be called, both having 
 the air-pump condenser, or, as it is generally termed, the old-fashioned 
 condenser. 
 
 FIG. 55. 
 
 A M, Fig. 55, is a Corliss engine, which has been running nearly thirty 
 years, and was one of the first ones built where it was to be run for economy 
 over some other one. The diagram is from a 32 -inch cylinder, 7 feet stroke, 
 running 36 revolutions, 40 pounds of steam, vacuum gauge 27^, scale 20. 
 Thirty-four pounds of steam are put into the cylinder ; the steam line is almost 
 absolutely straight does not vary half a pound ; the expansion line is very 
 good; if anything, we would open the exhaust valve sooner, allowing the 
 condenser to get hold earlier in the stroke, and yet the vacuum, at one-third 
 stroke, measures 20 inches, and further along 22 inches, bearing in mind that 
 
TWENTY YEARS WITH THE INDICATOR. 91 
 
 this 22 inches is in the cylinder. Aside from the alteration of the exhaust 
 valve, hardly anything is desired in this diagram. If the exhaust valve should 
 open earlier, so as to allow the condenser access to the steam quicker, the 
 value of the vacuum would, without doubt, be BH ^ H ^ H ^^^BHIMHIHHHI 
 increased from three to five per cent., and 
 might be more than that. 
 
 This engine has been noted for its econ- 
 omy, and has produced very gratifying results 
 to its owners. The steam valves, which are 
 now working in this engine, have been in use 
 for many years, without change, but there is 
 just this difference: the engine has been well 
 taken care of, although it has been idle for 
 some time, and the diagram shows plainly 
 enough that one of the objections that many 
 people urge against the Corliss engine has no 
 real foundation in fact, when the engine has 
 received the same care, or really less care than 
 some others, where parties make such an out- 
 cry about semi-rotary valves. In this place we 
 'must judge the engine by what it absolutely 
 produces, not by any man's preferences or 
 prejudices, and although this is an old machine, 
 it certainly makes a card that speaks well for 
 its maker and for its users. 
 
 In contrast to this, we present a diagram 
 from an engine built by Hicks & Hargrave, in 
 England, some years since, now in operation 
 in a New England cotton mill. The data is as 
 follows: Horizontal, 2O-inch cylinder, 42-inch 
 stroke, 62 revolutions per minute, spring 40, 
 boiler pressure 70, vacuum 28, hot well no. 
 This engine (diagram H H, Fig. 56) has four 
 grades of cut-off, which can be varied by hand, 
 while the engine is running, double-balanced FlG> 56> 
 
 poppet steam valves, 5^ inches, and the same style of exhaust valves 6^2 
 inches in diameter, with a double-balanced throttle valve and ball regulator. 
 
 We have erected the line at right angles to F, which is the atmospheric 
 line of the instrument, to show that the motions of the valves are very late in 
 opening, as the steam valve only opens after the piston has traveled from 
 the upright line to A. The cut off takes place slightly before B ; the expan- 
 sion line is excellent from B to C ; at C the exhaust valve opens, and this is 
 one of the best forms of exhaust in any engine, either condensing or non-con- 
 
92 TWENTY YEARS WITH THE INDICATOR. 
 
 densing, and exhausts early enough to allow a sharp falling-off ol pressure 
 a little before the piston finished its stroke. The vacuum is 24 inches almost 
 at the start, and 26 inches at the center of the stroke. The valve commences 
 to close at B, and is quite closed at E, while the steam valve commences to 
 open. This diagram, it must be remembered, is by a regulator which throttles 
 the steam in the main pipe. And, in contrast to the dimensions of pipes given 
 in our last lesson, this engine, with a 2O-inch cylinder, has a six-inch steam 
 pipe, instead of, as in one of the diagrams in the same lesson, having a 28-inch 
 cylinder and a six-inch pipe. This, therefore, accounts for the loss between 
 boiler and realized pressure in the cylinder, the boiler pressure being 70, and 
 the realized pressure, between A and B, only 52 pounds. This engine has 
 been running economically for some twelve years, although, perhaps, the 
 position of the valves might be improved somewhat, so as to increase their 
 economy. These are very considerably different in design and practice, both 
 being intended, practically, to accomplish the same economical result. We 
 have not the figures, nor is that the purpose of the article, which is only to 
 show the actual difference in practice between the makers ; and this may be 
 still a very good card for an engine regulating at a fixed cut off by a double 
 pressure. The pressure is governed by the regulator. 
 
 LESSON XXV. 
 
 THE diagrams illustrated in this lesson are again the result of actual 
 practice and a search after information. The data is as follows : Engine 10 
 inches by 24 inches, 72 revolutions, 67 and 68 pounds boiler pressure, 40 
 spring. Diagrams F F A, Fig. 57, is the engine as it was found ; the line at 
 the left is the boiler pressure ; the distance from this line to the dotted line, F, 
 is the distance the piston traveled before the valve was fully opened. It will 
 be seen that the valve made a series or succession of efforts to open, repre- 
 sented by the letters A, B, C, D. These will need no explanation to the man 
 who thinks, that the first movement of the piston is slow as it moves away 
 from the center, and that, as the motion is accelerated, each one of these steps 
 moves farther away from the . perpendicular line representing the boiler 
 pressure; and at each one of these steps, or stages, it will be seen that the 
 pressure increases until, finally, the steam line, E, is reached. The cut off is 
 
TWENTY YEARS WITH THE INDICATOR. 93 
 
 reasonably sharp, but it is terribly late. The line, F, is dotted through the 
 steam line, E, to show, that of 68 pounds boiler pressure, 37 pounds only are 
 realized upon the piston head, with this very late opening ; while, if we refer 
 to the other end of the diagram, we shall find that 47 pounds are realized ; 
 and, if we look at H, we find the departure from the perpendicular line is 
 about one-fifth of what it is at the other end of the engine. In other words, 
 the valves upon the left card open after the piston has moved away three 
 inches, while upon the right the valve commences to open after the piston has 
 moved three-eighths of an inch, and is quite open at one inch. The opening, 
 after the piston has receded one inch, reduces the realized pressure from 68 to 
 47, whereas, in the other end of the engine, we have only 37 pounds of real- 
 ized pressure out of the 68 ; this shows, therefore, that the rule is well founded 
 that when the valves do not open promptly, the loss of pressure increases in 
 proportion as the valves are late in their movements. It will not be necessary 
 
 for us to give any rule for this, for our readers must endeavor always to avoid 
 rather than to approximate ; for that reason we omit it. It is a self-evident 
 fact that this engine is doing badly enr ugh, and yet it is not the worst, by any 
 means, of those which we have. 
 
 Turning to diagrams F F B, Fig. 58, we have the same engine, same 
 dimensions, same speed, and approximately the same boiler pressure, but the 
 valves have been readjusted in their opening, and already show a very radical 
 improvement. In this case, we have sixty-seven pounds boiler pressure, 
 instead of sixty-eight, as in the other set of diagrams ; d represents the boiler 
 pressure ; the left hand diagram opens the valve a little quicker than we should 
 advise ; the right hand diagram a trifle later, but very nearly right. At A the 
 admission should come nearer the perpendicular line. It will be seen that the 
 admission touches the perpendicular line at the top, or, as the boiler pressure 
 was nearer realized while on the other card, at B, the Indicator line leans 
 slightly away from the perpendicular line ; therefore, the motion at A is a little 
 too quick, and at B is a little too slow, and there is also rather too much 
 
94 TWENTY YEARS WITH THE INDICATOR. 
 
 cushion at A. The steam line, in this case, is peculiar to poppet valve engines 
 that run at high speed. The left hand card falls away from the steam line ten 
 pounds at the cut off, c, and it is very nearly or quite the same upon the other 
 card at the approximate cut off, or the same point. In this case, the boiler 
 pressure is not realized within five or six pounds ; at the same time the dia- 
 grams are immensely superior to those of F F A. 
 
 While we know nothing of the result of this change, as regards the fuel, 
 we are safe in saying that diagrams F F A will probably do one-half the power 
 of diagrams F F B ; and that it would cost from fifty to one hundred per cent. 
 
 FIG. 58. 
 
 more coal to do it, to say nothing of the better regulation of the engine, with 
 the diagrams F F B. This adjustment is something which can be done by any 
 good steam engineer who has the Indicators, and who will give a little time 
 and attention to them. If our mill owners and power users would resort to 
 the Indicator more, there would be less growling about incompetence, and 
 much more satisfactory results in the combustion of fuel, more power would be 
 realized from the same coal, better work and less repairs, and generally a very 
 much better tone in and about engine rooms and among power users. 
 
 LESSON XXVI. 
 
 IN this lesson, we shall illustrate the Planimeter, as applied to the practical 
 measurement and computation of the Indicator diagrams, giving plain direc- 
 tions how to use it, and what not to do. The Planimeter was invented in 1827, 
 by a Swiss engineer named Oppenkofer. In 1849, another Swiss engineer, 
 
TWENTY YEARS WITH THE INDICATOR. 95 
 
 named Welty, made considerable improvements over Oppenkofer, but these 
 instruments were heavy, bulky, and not adapted to general use. In 1854, 
 M. J. Amsler, a mathematical professor at Schaffhausen, succeeded in making 
 the Polar Planimeter, and again this has been simplified materially. Our 
 illustration, Fig. 59, shows the Amsler Planimeter, as manufactured by the 
 American Steam Gauge Company, of Boston. The Planimeter is a surface 
 measurer, or, we might say, a plane measurer, for measuring the area of any 
 irregular form that may exist upon paper, to reduce it to the exact area con- 
 tained in that form upon any scale which may be applied to it. In other 
 words, the Planimeter computes the area of any form which may be submitted 
 to it, when properly handled, doing it by a mechanical process rather than a 
 mental one. As shown, it is but little larger than a pair of dividers, and is 
 enclosed in a nicely lined and leather covered case, which can be readily 
 carried in the pocket, is always ready for use, and, with a little care, will last 
 for years. Substantially this has been explained and the Planimeter illustrated 
 on a previous page, but we have also added to this explanation the general 
 features of the computation of the Planimeter, as applied to "working out" 
 the Indicator diagram. 
 
 We have taken a high-pressure, or non-condensing card, G M, Fig. 59, 
 and, for the sake of computation, we shall put the following data with it: 
 Diameter of cylinder 24 inches, length of stroke 60 inches, 60 revolutions per 
 minute, 30 spring. When using the Planimeter, we take a piece of thick 
 pasteboard, and get the bookbinder to paste a sheet of good blotting paper 
 upon it, pressing it over night, or until thoroughly dried. We never use a 
 finished or sized paper, or one that has a polis-h on it like glass. The surface 
 of this paper should be kept free from bunches, projections, grit, paste, or 
 dirt. A piece of blotting paper can be pasted upon a pine board, well 
 seasoned, and the board hung up out of the way, when not in use, in the 
 engine room or office. A piece of drawing paper can be pasted upon a board, 
 or, for immediate use, any piece of brown paper which is even on its surface, 
 not having bunches or projections, can be drawn out on a smooth board, and 
 the Planimeter set up at once. 
 
 Referring to Fig. 59, the point, A, must be outside of the diagram, or 
 outside of the area to be measured. The index roller, C, must travel smoothly 
 over the paper, and anything which interferes with its travel interferes with the 
 correctness of the computation to be made. Grit, dust, oil, or any foreign 
 matter, makes your computation at once worthless. The tracing point, B, is 
 what you will take between the thumb and fore-finger, running it around the 
 figure in the same direction that the hands of a watch travel. The point, A, is 
 the stationary one, and, having placed your diagram, you can change the 
 point, A, into any position you like that will not allow the roller, C, to come in 
 contact with the edge of the Indicator diagram, but will reach the most remote 
 point of the line traced by the Indicator, without touching the paper on which 
 
96 TWENTY YEARS WITH THE INDICATOR. 
 
 the diagram is traced. Let it roll freely upon the paper which forms your 
 table. In starting with the point, B, we usually do so in the corner of the card, 
 or any convenient point, taking care that a little pencil dot is made so that you 
 may start from the same point, and stop at that point so as to read closely. The 
 roller, C, after having adjusted the diagram and the Planimeter to the point 
 from which you are to start, may be lifted by raising the joint of the instrument 
 slightly from the paper, so that the on the wheel, and the on the vernier, 
 
 or little scale attached to the 
 joint of the instrument, shall 
 coincide with each other pre- 
 cisely. Then take the tracing 
 point, B, run it around the 
 diagram, being careful to fol- 
 low the line exactly, stopping 
 at the same point from which 
 you started. Now, to get at 
 the result, you must make a 
 correct reading. In our case, 
 we started at 0. When we 
 stopped, the 3 on the wheel, 
 and nine of the divisions be- 
 tween 3 and 4, have passed 
 the on the vernier; hence, 
 we read 3~,9~, then from the 
 cipher on the vernier we count 
 back until the mark of the 
 vernier coincides with a mark 
 on the wheel, which is 3, 
 hence, we have 3.93, and that 
 is the result of this computa- 
 tion. We now take the point, 
 B, and travel around the d'a- 
 gram, G M, once more; this 
 time we get 7 as having passed 
 the ; the eighth line has also 
 passed the 0; then we count 
 FlG - 59- up the marks on the vernier, 
 
 and find that the eighth mark on the vernier coincides with the mark on the 
 wneei. Previously we had 3.93, so we subtract 3.93 from 7.88. This time 
 we have 3.95. Surely, we have done one or the other carelessly, so we 
 repeat it. The next time we are more careful, and we get 3.93. This 
 is also repeated, until we are satisfied that 3.93 is right. In reading, we 
 sometimes come across curious mistakes. If we start at A, the corner of 
 
TWENTY YEARS WITH THE INDICATOR. 97 
 
 the diagram, G M, taking hold of the point above B, at that end of 
 the lever, with the point, A, at our left hand, and the point, B, coming 
 directly toward us, the diagram being slanting, the right hand toward us and 
 the left hand from us, taking the lever A in the diagram as a straight surface 
 parallel to our face ; then we bring the point, B, in the direction of the arrow 
 in the diagram, backward from where the Indicator made the marks when 
 attached to the engine. We come down the admission line, work to the left 
 on the exhaust line, go up on the expansion line in the direction of the arrow, 
 and come back to A again. Now, the top of the index wheel must be read to 
 the left of the in the vernier ; that is to say, in our last reading we have the 
 figure 7 on the wheel, which has passed the on the vernier to the left ; the 
 seventh line has also passed the first line on the vernier, and then we must 
 count upon the vernier to the ninth line, or until we find a line upon the 
 vernier which exactly corresponds with a line upon the wheel. The line upon 
 the vernier is the last one that is read. Remember, the readings on the vernier 
 are last, and that the numbers on the wheel must be read to the left of the 0, 
 when the instrument is properly operated. In this way you will not become 
 confused, and your results will not negative each other, making confusion. It 
 is not necessary to set the roller to the cipher on the vernier ; you can 
 commence anywhere, having perfected yourself with reading the instrument, 
 just as you can a clock when you look at it. It is better to use a small pocket 
 lens in reading this. The marks on the vernier are tenths of the marks on the 
 wheel. The marks on the wheel are hundredths, so that the marks on the 
 vernier are thousandths. Anything can be figured or computed by the Plani- 
 meter as well as an Indicator diagram, and, if you wish to test it carefully, 
 take a piece of zinc, and, with a pair of dividers, make a circle exactly one 
 inch in diameter ; then, with the Planimeter, measure this carefully, and you 
 will have the area of a one-inch circle, if you have drawn the line right. 
 
 Having ascertained that the area of G M is 3.93, we have now to measure 
 its length, and here is where beginners frequently make an error. The length 
 of the Indicator diagram can only be properly measured by erecting the 
 vertical lines, B, C, and to do this we use the steel triangles, placing one at the 
 base, and with the other drawing the lines, B, C, just as closely as we can to 
 the pencil mark actually made by the Indicator; and we must measure the 
 extreme range of travel of the instrument, else our computation is incorrect 
 and unreliable. It does not matter what the shape or form of the lines drawn 
 by the Indicator, follow the lines made by the Indicator, and this gives the 
 power transmitted. Sometimes, in figuring for other purposes, we have to 
 take in an area not defined by the Indicator. In measuring the diagram of a 
 condensing engine, it can be measured in either one of two ways. That por- 
 tion which is above the atmospheric line, or the high pressure, can be measured 
 separately, to see what is being done ; and that which is below the atmospheric 
 line can be measured to see what the condenser is doing ; or, if you simply 
 
9 8 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 wish to ascertain the amount of power exerted by the engine, then include 
 the whole figure above and below for obtaining the area of this figure, and 
 we think the process has been carefully described. 
 
 The next point is to reduce it to something which shall represent power 
 or work. In this case we have 3.93 on the Planimeter, the length of the 
 diagram is 4ff inches, the decimal for ff is .7812. We will, therefore, 
 divide 3.93 by 4.7812 inches, and this will give us the height of an ordi- 
 
 nate which will make a rectan- 
 gular form that will represent 
 precisely the area of the dia- 
 gram, G M. Dividing 3.93 by 
 4.7812 gives us .821. This is 
 a decimal of an inch. As the 
 spring with which we are 
 working is number thirty, or 
 thirty pounds to the inch, we 
 multiply the height of the 
 ordinate by thirty, which gives 
 us the number of pounds mean 
 pressure exerted, which is 
 24.63. This process is the 
 same for any size engine, or 
 any number that may be had 
 on the Planimeter, and to sim- 
 plify matters in our own prac- 
 tice, whenever we are figuring 
 an engine, we do it as follows : 
 The diameter of the cylinder, 
 reduced to square inches (see 
 table on properties of steam), 
 multiplied by the number of 
 feet per minute, divided by 
 33,000, gives us what we term 
 the constant, which represents 
 the number of horse-power ex- 
 erted by each pound of mean 
 pressure upon that piston at 
 the speed which is given. In 
 this case, therefore, the following formula is applied: The diameter of the 
 piston being 24 inches, area 4 52-39 square inches; five feet stroke, 60 revo- 
 lutions, make 600 feet per minute ; 33,000 pounds one foot high in one 
 minute is one horse-power ; hence, 452.39 X 600 -^ 3 3>ooo =8.22, which 
 represents 8.22 horse-power for every pound of mean pressure which the 
 
 FIG. 60. 
 
TWENTY YEARS WITH THE INDICATOR. 99 
 
 Planimeter gives for any diagram upon this particular engine at the speed 
 we have given. Now, as we have 24.63 pounds mean pressure, multiply 24.63 
 by 8.22 and it gives 202.4586 horse-power. 
 
 The rule for reducing the figure of the Indicator is as follows : Get the 
 reading of your instrument accurately ; where but slight differences exist, take 
 three or four readings and average the result ; divide this by the length of the 
 card, taking care to include the extreme length of any variation. When this 
 result has been attained, multiply by the scale of the spring which you are 
 using ; this gives you the pounds of mean pressure. Multiply the pounds of 
 mean pressure by the co-efficient, which represents the number of horse-power 
 of each pound of mean pressure, from the rule given above, and you will very 
 materially simplify the process of working up these diagrams. If you are used 
 to logarithms you can do them with about one-fifth the figures. 
 
 The question is frequently asked as to "what shall I measure in other 
 respects." The following illustrations will answer, as examples, but the rules 
 which we have given above will apply to each and every one, changing the 
 figures according to the facts as they exist, observing always to take good care 
 of the decimals and whole numbers. In Fig. 60 we have drawn the outline of 
 two different Indicator diagrams, embodying radically different principles, in 
 order to show what may and must be done with the Planimeter whenever 
 using it. The diagram, A A, which is purely a fanciful one, based on the same 
 steam pressure as B, is drawn for the purpose of showing that any measure- 
 ment made is taken by starting the perpendicular line at the extreme point, 
 D, and measuring from G D. Should we drop the horizontal line from C to 
 C, we should not include the actual length of the figure over which the 
 Indicator traveled. In the diagram, B B, it will be seen that the end of the 
 expansion line falls below the atmospheric line, making the loop, F. In 
 running the Planimeter over the outline of this figure, follow the lines precisely 
 as the steam Indicator left them upon the paper, in the direction of the arrows. 
 Now the space, F, really acted upon the piston of the engine by holding it 
 back. The Planimeter deducts this space from that above the line in such a 
 way that actual pressure upon the piston only is given. In this case, we must 
 draw the vertical line from E to E, and the length of the card, B B, is from 
 H to E. In brief, the rule for the action of the Planimeter, in computing areas, 
 is to follow the outline f the card as the instrument leaves it, without any 
 reference to ideas. It is sometimes a question, in the case of an engine with a 
 large amount of back pressure, how to figure it. Take the area of the figure 
 bounded by the instrument which gives the transmitted power, and, if you are 
 figuring for fuel, or desire to know what the whole power exerted by the steam 
 is, take in all the back pressure, as in the diagram, G M. The line, D, in this 
 card, is an imaginary one, and represents what might be an enormous back 
 pressure. Now, if this engine is exhausting under this pressure, E being 
 the real atmospheric line of the instrument, and D the supposed line of back 
 
ioc TWENTY YEARS WITH THE INDICATOR, 
 
 pressure, then \ve must measure the area between E and D for fuel, for, as a 
 matter of fact, the boilers furnish the steam to do this work with, but the work 
 is not figured in because it is spent to no purpose. The power is consumed 
 in the engine itself, and is not, therefore, transmitted to the machinery 
 beyond. 
 
 The use of the Planimeter does not require a particle more skill than does 
 the use of any other good tool about the mill ; it works to ten-thousandths of 
 a square inch ; it is a delicate little instrument, and must not be thrown around 
 like a pair of gas-pipe tongs or a blacksmith's hammer. A very little puts it 
 out of order, and then it must go into the hands of some man who can put it 
 into order again. We have one of the large ones, which we have carried 
 probably 25,000 miles, within the last five years. It never has been out of 
 order for a moment ; it is as perfect as the day we bought it, eleven years ago, 
 and, if it is not abused, will be good twenty years hence. An Indicator may 
 be properly classed in exactly the same category ; it is expected to detect 
 little differences or discrepancies, and it requires to be handled very carefully. 
 Either instrument is as serviceable as a good watch, and requires just about the 
 same care in the handling, and, if they are well used, will give accurate results 
 every time. 
 
 LESSON XXVIL 
 
 THE diagrams, here shown, are very interesting comparisons. Diagram 
 B S N, Fig. 6 1, is from a Corliss engine, built by George H. Corliss, in 1865, 
 with his old style valve-tripping, tripped direct by the governor, closed by 
 springs, 20^ inches diameter, 42 inches stroke, 84 revolutions per minute, 100 
 pounds of steam in the boiler, throttle-valve wide open. The parties who own 
 this valve, write as follows : " Enclosed is diagram from our engine, as it was 
 running on the nth of March. We call it a good card." In response to an 
 inquiry, they wrote as follows: "Our engine has very variable work. At 
 times it will be doing more than 300 horse-power, and instantly drop to 150, 
 or below, and the governor regulates so promptly that it will not vary a turn 
 
TWENTY YEARS WITH TH 
 
 TOR. 
 
 101 
 
 when the changes are so sudden and extreme. We have bored out the valve 
 seats twice, and put in one set of new valves since it was started. It had poor 
 management in early life, and from 1865 to 1870 the expenses for repairs, cut- 
 off attachments, oil pumps, and eccentric arrangements, were large, but the 
 trouble arose from the incompetency of the mechanic in charge. Since the 
 new valves were put in four years ago we have not spent one hundred 
 dollars in all repairs on the engine, incident to her regular work. We run ten 
 hours a day, and from 305 to 306 days in each year." 
 
 Here is an engine that was, for 
 the first five years of its life, badly 
 abused, in charge of an incompetent 
 man, the bill of expenses for re- 
 pairs was large, but since the new 
 order of things all this has been 
 radically changed. We frequently 
 hear it said, mostly by parties 
 who are interested in some other 
 style of engine, that the Corliss 
 engine requires reboring, refitting, 
 and a new set of valves every few 
 months, or weeks, even, but we 
 seldom find people who are using 
 them, where they have anything 
 except a numskull in charge of 
 the engine, who corroborate any 
 such kind of a statement or story. 
 We have drawn vertical lines, and 
 find that this engine is taking its 
 steam very nearly right ; in fact, the 
 admission line and the vertical line 
 are so near together, that we would 
 not advise any alteration at all. 
 The steam line of the engine is 
 very good indeed, considering its 
 high speed, and the amount of 
 work it is doing. With one hun- 
 dred pounds in the boiler, we get 
 92 pounds at A B. The steam 
 line on the head end is hardly as good as on the crank end, and it falls, before 
 cutting off, ten pounds, from the initial pressure realized in the cylinder. 
 The expansion lines are very good ; the only change we would suggest, would 
 be the opening of the exhaust valve at C, D, making the dotted line down to 
 the atmospheric line of the instrument, so as to save the little back pressure 
 
 
102 TWENTY YEARS WITH THE INDICATOR. 
 
 upon the return of the piston. This would, undoubtedly, make a little more 
 compression, and would make the engine run fully as quietly as now. Practi- 
 cally, the diagrams are first-rate, better than the average, which only goes to 
 prove that the Richards Indicator, with which they were taken, with a 40 
 spring, is reliable, when kept in good order ; and we believe, with proper care, 
 it will take a steam engine up nicely to a speed of one hundred revolutions. 
 The diagrams in question were taken with a three-way cock, and are of no 
 value in the adjustment of one end with the other. 
 
 In contrast with diagram B S N, we publish diagram H E W, from an 
 engine which has been running 30 years, old fashioned slide valves, cutting off 
 at half stroke. The cylinder has never been rebored. It is 20 inches in 
 diameter, 4 feet stroke, 55 strokes per minute; boiler pressure 75 pounds; 
 mill heated by exhaust, as also^the wash room and dye room of the concern 
 from which this was taken. The scale of the diagram was 44 pounds per 
 
 HEW 
 
 FIG. 62. 
 
 inch. Fifty-five pounds of the boiler pressure is put upon the head of the 
 piston, cutting off at about one-third stroke. Six pounds is lost at the cut off 
 from the pressure realized at the commencement of the stroke. The expan- 
 sion line is somewhat wavy, and the back pressure is not excessive, when it is 
 considered what an amount of work the engine is doing. While this engine 
 is not among the most economical motors of the day, it is an example of old 
 style engineering, which is capable of doing lengthy service with reasonable 
 economy. We are not informed as to the amount of fuel used for the power. 
 It will not, however, compare with the economy of diagram B S N. At the 
 same time, diagram H E W is a vast improvement over engines built in its 
 day, some of which are now running. We have hardly the data at hand for 
 comparing the relative efficiency. We would not advise the purchase of an 
 engine of this class, from an economical stand-point, and yet, some of them are 
 doing fully as good work, for the pounds of coal consumed, as modern engines 
 not built upon the right principles. 
 
TWENTY YEARS WITH THE INDICATOR. 103 
 
 LESSON XXVIII. 
 
 THE object of the diagrams in this lesson is to illustrate, as the acquaint- 
 ance with the Indicator extends, some little occasionals that will persist in 
 cropping up, and not always to the pleasure or profit of the party who is 
 operating the instrument. These diagrams are, for the sake of convenience, 
 traced upon the same block. As they are both from actual occurrences, which 
 are liable to occur at any time, we have made them the subject of this lesson. 
 The Indicator is a delicate instrument, and requires care; it also requires, 
 what good printers have to mix with their ink to get nice work a little 
 brains and practice in the use of it. The card, A, Fig. 63, is taken from a 
 Richards instrument on a Corliss engine. The engineer discovered, all at 
 once, that the Richards Indicator was not reliable, and he made this discovery 
 by the help of a gentleman who was very strongly prejudiced in favor of 
 another Indicator ; and this gentleman, who was educating the engineer, forgot 
 entirely to tell him that possibly his Indicator might be out of adjustment, 
 even if he knew it himself; so the engineer was writing for advice regarding 
 whose instrument he should buy, and the diagrams came to us through the 
 mail. Now, if our readers will pay attention, some of them may know imme- 
 diately what is the trouble when they see this thing repeated. Starting at A, 
 or at the termination of the exhaust and commencement of compression, we 
 notice that the line is heavy ; it gradually comes to be dots, and the dots are 
 further apart, there is no steam line, and, after the expansion has begun, 
 it starts in again with dots, and finally, after some time, makes a heavy line 
 again, and at A, on the expansion curve, comes down to about the right sized 
 line again. Now this instrument was a Richards, made several years since. 
 We wrote the engineer to please send us his instrument, and thought we could 
 tell him where the trouble was. Upon our applying the instrument, it did not 
 take over twenty seconds to find the whole trouble. The piston barrel is 
 surrounded by a casing, and the paper cylinder is held in place by a short 
 bar. The stand which surrounds the piston casing of the instrument had 
 been thumped, and the bar had been sprung so that the top of the paper barrel 
 was further away from the top of the piston than the bottom of it. Conse- 
 quently, when we fastened the pencil to the bar, it made a heavy mark at the 
 bottom, and made no mark at all at the top. In other words, the paper 
 cylinder was out of parallel with the piston rod of the instrument. Sometimes 
 the cylinder gets sprung exactly the other way, so that there will be a heavy 
 mark at the top and none at the bottom. A little readjustment and correcting 
 
io 4 TWENTY YEARS WITH THE INDICA TOR. 
 
 of the springs, which had been used a number of years, and after 
 loosening the nuts in the heads of the springs, we put the instrument back 
 again upon the engine, and it made elegant diagrams, so much so, that on its 
 return the engineer decided that he did not know all there was about an 
 
 Indicator, although he had been using it 
 a number of years ; and, instead of buy- 
 ing a new instrument, concluded that a 
 reliable instrument would answer just as 
 well. This is a thing that not infre- 
 quently happens. We have seen parties 
 lay an instrument down upon a bench, or 
 hit it carelessly against a weight, shaft, 
 or something, and then, for the next 
 three months, grumble about their Indi- 
 cators having given out, or got out of 
 order, when, as a matter of fact, a little 
 carelessness put the instrument out of 
 shape, and lack of patience, or pains in 
 ascertaining just where the trouble was, 
 kept them from realizing their folly or 
 ignorance. 
 
 In card B, Fig. 63, we have quite 
 another case, yet not a particle less inter- 
 esting or less profitable. In this case, 
 the compression line will be found to be 
 dotted ; the steam line is very good, but 
 the expansion line the upper portion 
 of it is anything but good, and it 
 finally drops away into dots ; and down 
 on the expansion line, B, there is a 
 sudden falling off, and a very erratic 
 continuation of the expansion line. This 
 is a peculiar, but by no means impossible 
 diagram, and, if our readers will draw a 
 line parallel with the atmospheric line of 
 the instrument on the diagram, they will 
 find that the dots commence at about the 
 same height from the parallel line at both 
 FlG - 63- ends of the card ; in other words, that 
 
 the dots on the compression or admission line, and on the expansion lines, 
 commence at just about the same height from the atmospheric line in both 
 cases. This can hardly occur from any action of the steam in the cylinder. 
 The party who sent this diagram took it from the Thompson instrument^ and 
 
TWENTY YEARS WITH THE INDICATOR. 105 
 
 he declared his belief that the Thompson instrument was not over half made. 
 We requested him to send it to us, which was promptly done. Somebody, 
 who had been trying to handle it, had bent the piston head on the end of the 
 rod in one direction, and had sprung the piston exactly in the other direction. 
 When the bend in the piston rod, or shell which surrounds the connection 
 with the parallel motion above, came through the bearing in the top, it 
 necessarily bound, although but slightly, and .the pencil jumped. The steam 
 line is straight, or nearly so, for the best of reasons : the piston of the instru- 
 ment was at that moment standing still, the pressure being so nearly uniform. 
 When it starts to descend, it makes a very fine cut off, but after it descends an 
 eighth of an inch, then the trouble commences by the piston beginning to stick, 
 and sticking worse until it makes dots. Beyond the letter B, on the expansion 
 line, where the jog is marked, it drops off instantly, and, if the curve is 
 applied, the expansion line at this point will be found too high. Up to this 
 time, the pressure in the cylinder was nearly enough to help the bend in the 
 piston-rod, but, when the steam became thoroughly expanded, then the piston 
 went down with a jump, and the line beyond it shows exactly how it worked. 
 Upon a careful examination of this Indicator, the bend was found to be very 
 small, but was just as essential as though it had been bent double. The piston 
 was sent back and reorganized, a new piston put into the instrument, and 
 some of the most elegant cards taken at the first trial. Upon returning the 
 Indicator to our inquirer, he wrote briefly, saying, " I believe that the Thomp- 
 son Indicator is well made, and that I am a good deal nearer a blockhead than 
 anything else. Please don't give this away, and the next time I am stuck I 
 shall know where to send." 
 
 Now these cases are possible. It does not do to p'ut your Indicator in a 
 vise in order to get at any unscrewing of the parts ; it must not be run by 
 tallow or cylinder oil blown into the piston, for the piston was not made to 
 work in that kind of material any more than in a sand bank ; it requires, at 
 times, a little patience, and makes a good deal of annoyance, as we have often 
 found, at the expense of burnt fingers and abraded knuckles ; but impatience, 
 and getting out of sorts, don't make the Indicator work better, and it does 
 frequently get a man into a complete tangle. It makes no difference how 
 much pains the maker of the instrument takes in its adjustment, the machine 
 must be used as a machine, and as a very intelligent one. 
 
io6 TWENTY YEARS WITH THE INDICATOR 
 
 LESSON XXIX. 
 
 THE different classes of engines in use show, to the investigator, peculiar 
 vagaries and radical departures from either the theoretical or practical, so far 
 as economy is concerned. At the same time, men have peculiar ideas, and 
 frequently indulge themselves in experiments which, sooner or later, develop 
 into such peculiar looking objects as we have for the subject of this lesson. 
 We have had much to say and do with the rotary valve, and now we have a 
 fixed slide valve, or, as it is usually spoken of, a plain slide valve, in which 
 case there is no cut off beyond that limited by the carrying of the steam. The 
 four sets of cards shown represent four different engines; we might, with 
 perfect propriety, say four abortions in the use of steam. A little explanation 
 will show that each one of these was an attempt to work out somebody's ideas 
 in the use of steam. 
 
 FIG. 64. 
 
 Diagrams A, Fig. 64, is what is termed a rotary-plug valve, scale 40, and 
 it might, perhaps, puzzle some of our readers to ascertain which was the 
 steam end, and which the exhaust end of the diagram. Both diagrams are 
 given, but the subject is hardly worth more space than we have now given it. 
 The scale is 40, and the base line, or lower line in the card, is the line of rest, 
 or the atmospheric line of the instrument. The man who arranged this did 
 not believe in clap-trap valve-gears, and he succeeded in making his own vaive 
 gear work. To use a little quotation, " No need of such nonsense ; we can 
 make a simple, cheap engine that will work just as economically as any of 
 them." Strange as it may seem, this man really had the good sense to make 
 use of the Indicator, and he was very soon converted to a clap-trap valve 
 gear. We don't wonder that he was. 
 
 Diagrams B, Fig. 65, show what may occur to the plain slide-valve 
 engine when the eccentric slips from one-quarter to one-third of its way on 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 107 
 
 the main shaft. The steam and exhaust are very late, and this engine would 
 make first-rate junk, and would be cheaper in the junk pile than in the engine 
 room if it had to work in this way. 
 
 FIG. 65. 
 
 Diagrams C, Fig. 66, are a curiosity in the literature of engineering. The 
 engine was moderately well constructed, the steam line, as shown, is very fair, 
 the exhaust commences to open at about the right place, but it never gets 
 open enough to get rid of the back pressure. But the trouble in this case is 
 not in the engine, it was, rather, in the vague ideas of a man who did not 
 believe in heating his mill by direct steam. He was going to economize his 
 exhaust. His train of argument was something like this : "If my exhaust 
 steam can be carried through a long pipe, I can extract all the heat from it, 
 and save what would otherwise be thrown away." Not satisfied with this, he 
 had another exceedingly happy thought: having used a considerably long 
 
 FIG. 66. 
 
 circuit, he kept reducing the size of the pipes for fear that one or two 
 extra degrees of heat might escape his grasp, until, finally, what little heat 
 there was left in the steam, was made to escape through a three-quarter inch 
 pipe, and a tank of water. The diagram shows that he made a brilliant 
 success in one respect, and a brilliant failure in the other. He probably 
 succeeded in extracting all the heat, but at a slight expense in fuel. The 
 figures show the reading of the Planimeter. It will be seen that the effective 
 work yielded was 238 out of 773. In other words, it required 773 horse- 
 power, if you choose, to develop 238 horse-power, transmitted to the 
 
io8 TWENTY YEARS \VITH THE INDICATOR. 
 
 machinery, 238 horse-power being yielded by the belting, and 435 horse- 
 power being consumed in pushing the steam out of the cylinder, through 
 several miles or less of pipe, into a tank of water. While the amount of 
 power in this case is largely exaggerated, the actual proportions are precisely 
 as stated. He did heat the rooms, and he did squeeze the last item of heat 
 out of the steam ; which, in turn, revenged itself upon him in his fuel bill, as 
 any sensible man would long before have discovered. At the commencement 
 of this operation he congratulated himself. We can imagine him rubbing his 
 hands with glee, but when the fuel bills began to come in, his face grew as long 
 as a broomstick ; he wondered somewhat, after a little time wavered, then 
 doubted his own success, and, as a last resort, called in the doctor ; and we 
 will let him down easy, by saying tha<- he now uses direct steam for heating 
 his mill, runs his exhaust steam through a heater, and takes very great pains 
 that his heater has an extravagantly good amount of exhaust room, that the 
 steam is not choked anywhere, and looks out for sharp turns in every direc- 
 tion ; and he is not only a converted man, in the strictest sense of the word, 
 but is richer, both by experience and in his pocket. Heating by exhaust 
 steam is a great hobby with some people, and others who have tried it have 
 found that it is, unless properly managed, very expensive ; in fact, so much so, 
 that many concerns have abandoned it, preferring to heat their feed water, and 
 then, having economized in a sensible way, they can well afford to make more 
 steam, and send it around by direct circulation. It hardly pays to heat by 
 exhaust steam when it troubles the power of the engine, and this party referred 
 to above was, no doubt, an unbeliever in the utility of Ihe Indicator, until he 
 was converted by main force. In other words, it required him to bring his 
 skull in contact with a stone in order to set him thinking. 
 
 FIG. 67. 
 
 Diagrams D, Fig. 67, represent an experiment upon an elal orate scale, by 
 an engine builder, and a man of some considerable experience, who really 
 made a pretence of building a good engine. This man also had a hobby. It 
 was, that the impact of the steam upon the piston head was tremendous, and 
 that, instead of doing the work as it should, by attempting- it in that way. 
 continually tore the engine to pieces, or set it to thumpin? and pounding 
 
TWENTY YEARS WITH THE INDICATOR. 109 
 
 so he had a brilliant idea. As the impact of the entering steam was altogether 
 wrong, and could not do any work, for the crank was on the centre, he 
 concluded that the time for the action of full pressure was in the middle of 
 the stroke, as he believed in putting the steam where it would do the most 
 good. 'He constructed his ports and valves to work as these diagrams show. 
 He believed he had the philosopher's stone and the true theory of steam 
 distribution, and either his engine, or one of the high speed engines, must fall. 
 His conversion was, perhaps, as forcible as the engine. He admitted steam 
 gradually at first. (The diagrams are taken wjth a 40 spring.) It will be seen 
 that the steam raised in the middle, struck to the highest pressure, takes a back 
 lash before it gets ready to exhaust, and really bears a very fair analogy to the 
 shape of a sperm whale's head. The figure is a literal representation of the 
 obtuseness of this man, who afterward found that there was a good deal of 
 difference between tweedle-dee and tweedle-dum. 
 
 There is nothing good to be said of any of these diagrams, yet they are 
 not, by any means, the worst that could be produced. Taken as a class, A 
 and B are fair representations of what is being done regularly, while C and D 
 are monstrosities, and are of no more practical use, or real practical value, 
 than a wooden man would be as engineer. We have given them, not because 
 they conveyed valuable instruction to our engineers, but for the reason that 
 this lesson is intended more for steam users and for some of those parties who 
 belong either to the chronic or constitutional grumblers. We know, person- 
 ally, where there are engines running worse than either of the four cards, and 
 not five miles from where we are now writing. 
 
 LESSON XXX. 
 
 THE diagrams for this lesson are both from men who are running engines. 
 Diagrams A, Fig. 68, are from an engine manufactured by the Hartford 
 Engineering Company, of Hartford, now in operation in a New England 
 cotton mill. The data which comes to us is not complete. Steam 72, scale 
 30, revolutions 124 per minute. The steam line is very good indeed. The 
 cut off of this engine is closely defined ; the expansion line would seem to be 
 
no TWENTY YEARS WITH THE INDICATOR. 
 
 very good, but, as the clearance is not given, we cannot state definitely what 
 its approximation is to the so-called theoretical curve. The exhaust valve 
 upon either end opens early at A, and the back pressure is very small. We 
 have no means of knowing whether the steam is being exhausted into the 
 open air, or is being used for heating. At any rate, the back pressure is less 
 than two pounds. The compression lines made by the valves of this machine 
 require less length of stroke, and approximate to steam pressure nearer than 
 that of the generally constructed high-speed engines. In other words, there 
 is less compression in volume as regards the proportion of compression to the 
 whole length of the stroke, and the compression is made effective by what 
 appear to be close working valves. The engine falls about ten pounds short of 
 boiler pressure ; but, unlike most high-speed engines, the steam line does not 
 drop off ten pounds from the pressure first realized on the piston. The falling 
 off of the steam line from the first impact is not appreciable, in fact, cannot 
 
 FIG. 68. 
 
 be measured by the scale used. It is rather a" matter of regret that more data 
 did not accompany the card. The valves would seem not to be leaking ; their 
 action is proportionately the same ; the expansion line, we have little doubt, 
 will approximate very nearly the curve ; and yet, much of this depends on the 
 condition of the steam, and the distance of the engine from the boilers ; but, 
 taking it precisely as it reaches our hand, it is a very good diagram. This 
 engine must not be confused with what is known as the Buckeye engine, 
 built in the West. This is peculiarly an Eastern machine, and is very far 
 superior to any cards we have ever seen taken from the Ohio machine. 
 
 Diagrams C F, Fig. 69, come to us all the way from St. Louis, and is 
 from the Reynolds-Corliss engine, built by Allis & Co., of Milwaukee, Wis. 
 The data, which comes with this diagram, is : Diameter of cylinder 28 inches, 
 length of stroke 5 feet, revolutions 63, spring 40, boiler pressure 75. The 
 peculiar feature of this engine is its beautiful compression lines and the close 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 in 
 
 expansion line. The steam pressure is very nearly the same, falling nearly ten 
 pounds from boiler pressure. The dotted lines over the steam line would lead 
 us to suppose, not having the facts in our possession, that the steam was either 
 drawn some ways from the boiler, or else through a pipe that was hardly large 
 enough to supply the demand made by the opening of the steam valves. It 
 will be noticed that the head end falls off more radically than the crank from 
 the steam line or induction pressure, and this fact would give us the rounding 
 
 FIG. 69. 
 
 over of the corner from the fact of the steam valves closing on a deficient 
 supply of steam, so that the steam is, to a certain extent, wire drawn through 
 the valve after it commences to close, and this, in fact, is the only poor feature 
 of this diagram. Judging from the appearance of the cards, we should say 
 that the engineer in charge had some pride in his engine, and was endeavoring 
 to see how well he could do with it, rather than how much he could get out of 
 it. Both these cards were taken by the engineers themselves. 
 
 LESSON XXXI. 
 
 A PRACTICAL illustration of the value of the Indicator could not be more 
 forcibly made to the mind of any man, who is capable of reasoning, or one 
 who is not prejudiced, than the one which is here presented. We frequently 
 receive inquiries as to peculiar points of working, some of which cannot be 
 explained satisfactorily without a careful investigation, and others which can 
 
112 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 never be remedied until after the faults which are left by the builder in the 
 machine are all removed. 
 
 In order to save space, and, at the same time, to make the lesson all the 
 more forcible, we have drawn two sets of diagrams upon the same block. The 
 disproportion in the outlines which follow each other can be studied by any 
 one who is interested. Briefly stated, the case is as follows : Some time ago, 
 the writer of this was called to look at an engine just outside the City of 
 Boston. The engineer did not believe in Indicators, and considered that any 
 man who attempted to meddle with the engine, after he had placed it where 
 it should run, had taken in a " pretty fat job," to use exactly his own words. 
 However, the engines were adjusted, although but one of a pair was generally 
 used. After he saw how easy it was to control the movement of the engine, 
 and to bring everything into working order, he became very much interested 
 in the Indicator, and the agent of the concern ordered a set, with which the 
 engineer is now very greatly interested, and is keeping close track of his 
 engine. The engines were carefully adjusted, and, as some changes were 
 
 FIG. 70. 
 
 going on at the time of our visit, we advised the changing of the main steam 
 pipe leading to the engine. As some especial piece of casting had to be 
 procured, it was not done at the moment. So we were somewhat surprised, a 
 short time afterward, to receive a pair of diagrams, one taken at either end 
 of the cylinder, on the same stroke, of which A A are almost absolutely exact 
 reproductions, together with a note from the agent, saying that there was some 
 trouble with the engine, but, as nothing had been changed that they were 
 aware of, he could not explain, nor could the engineer, why they should make 
 such cards ; would we telegraph him, the instant we received his letter, what 
 to do? Here was a puzzle. The crank end is the same for each diagram, in 
 general, at least, but the disproportion between the head and crank dotted 
 line is rather too far out for general use. The other engine was disabled. He 
 
TWENTY YEARS WITH THE INDICATOR. 113 
 
 had worked all day Monday in trying to get at the matter, so that our letter 
 was received Tuesday morning. We telegraphed him at once to take off the 
 head end of the cylinder and see if there was anything jammed into the port, 
 or if the valve was free in its working. After two or three hours, back came 
 his answer : " Port all clear ; will be ready to run in half an hour. What shall 
 we do next if the card don't improve?" Away went our answer: " If the 
 same difficulty still exists, pull off the new valve and see if there is anything 
 in the steam -way so that the valve don't get steam ; if this don't cure it, I will 
 be there at five o'clock." This left our office about eleven o'clock. At four 
 four o'clock, P. M., came another: "No improvement on taking off the 
 cylinder head; we followed directions, and dug out a blacksmith's shop; just 
 connected up, and everything is lovely and on the top shelf." Next morning's 
 mail brought us along a laughable letter, enclosing diagrams B B, showing the 
 boiler pressure at C C, scale 40, engine 60 X 23, running 56 revolutions. The 
 end of this letter was about as follows : " If there is a man in this country, 
 today, that swears by the Indicator, it is your old friend, our engineer, but he 
 thinks that a little Indicator, some telegraph, and some common sense, work 
 in pretty well together." Herewith follows an explanation. The joke of the 
 matter was, that he threatened to send us the whole batch of stuff taken out 
 of the steam passage between the main valve and the steam valves. 
 
 " When the new steam pipe and valve arrived, our master mechanic, who 
 usually has charge of these things, joked the engineer about his not loving 
 that ' feller ' who came out with the Indicator. They had some good-natured 
 chaff, and when it came stopping-time at night, the master mechanic, thinking 
 to make some of his tools all safe, put a large lump of copper, a short stub 
 wrench, an S wrench, and a piece of lead, which he had been using, into the 
 steam chest of the engine. The next morning the master mechanic was called 
 to another part of the yard, and, before leaving, sent one of the men to the 
 engine room, expecting to join him in a few moments. Being bothered, 
 himself, by something which demanded his attention, the engineer and his 
 assistant, being in a hurry to get that mill started, helped machinist number 
 two to lift the big valve in its place, and then they had a hunt after the 
 wrenches, not, however, finding them. Others were procured, the valve was 
 put on, the gaskets placed, and everything screwed up for ' keeps.' Steam 
 was then put on, and the engine started slowly to see that everything was all 
 right. The result you have in the cards. The joke of the whole thing is 
 that, by changing the men, one had forgotten about his tools, and the other 
 knew nothing of it, so that we were all day digging out our machine shop. 
 The lesson has not been without good results, and if our master mechanic is 
 easily nettled now by reference to his new tool chest, you can imagine why he 
 appreciates the joke. The engineer in turn laughs at the mechanic, who had 
 previously chaffed him (the engineer) about the Indicator affair, by threatening 
 to take out a patent for his new tool chest." 
 
ii4 TWENTY YEARS WITH THE INDICATOR. 
 
 Our readers have here a stubborn fact, and an expensive one, but, at th^ 
 same time, a very instructive one. The diagram, A, head, shows conclusively 
 that the steam is shut away from the piston by some reason or other. Some- 
 times tools have been clogged in the port, but we do not know that the passage 
 was ever before, in our own experience, blocked up back of the port. A lump 
 of copper, five and one-half or six inches long and more than two inches in 
 diameter, and a piece of lead as big as two ordinary fists, cover a large 
 proportion of the length of the steam port. Come to mix these up with a 
 stub wrench, made from inch and a half iron, and some other little matters, 
 which, fortunately for the valve, were so placed by the blast of steam that they 
 did not pass over the valve and catch between the valve and the port, or they 
 would have made music, and an expensive bill of repairs, and effectually shut 
 the steam away from the head valve of the engine. One of the beauties of 
 the automatic adjustment is seen in A, crank. The steam pressure steadily 
 diminishes from the time of impact, and the steam line drops nearly ten 
 pounds ; but, compared with B, it carries steam very much longer, endeavoring 
 to make up for what the head end, A, lacks. The race, however, was a stern 
 chase, and it was impossible. But after the machine shop was removed from 
 the steam chest, B B shows that the engine was in excellent adjustment, one 
 valve, if anything, being a trifle off time, but the steam lines are so nearly 
 good that it is not necessary to criticise them. 
 
 There is also another lesson to be drawn from this, viz. : It don't pay to 
 joke too hard, or to play tricks, one workman with another, in a job like this, 
 where one man may forget what he has done, or another one forget exactly 
 where he left off. It was a very fortunate occurrence that a smash-up did not 
 occur, and had some of these tools passed the steam passage to the front of 
 the steam valve, there might have been a smash with serious consequences. 
 The Indicator only tells the truth, and, if the steam is shut away from the 
 piston, it may not write upon the Indicator card that practical joking is 
 expensive, or a machine shop out of place has choked the steam off, but it 
 does tell distinctly that the steam don't get to the piston, and sensible men, 
 like those who use the Indicator, usually commence an investigation without 
 waiting for a smash. There was never a better illustration of the real value 
 of the Incficator than this ; and, although it is absurd in one point of view, we 
 consider the instructive as predominant, hence, give it a place among our many 
 lessons. 
 
TWENTY YEARS WITH THE INDICATOR. 115 
 
 LESSON XXXII. 
 
 THE point in the following needs a little preface, in order to be thoroughly 
 digested by our readers ; we mean, of course, the practical ones. Yet it is 
 only one case where a consulting engineer has to trample down both ignorance 
 and prejudice, and can only let daylight shine, where prejudice and ignorance 
 has sway, by the use of a sledge hammer. The point in question is one which 
 reaches directly the pocket of the victim ; and for this, steam users are not so 
 much to blame as those men who sign themselves " experts." Briefly, the 
 case is as follows : A manufacturing company had a large engine and boilers, 
 and a first-class, sensible, clean, and intelligent engineer. The engineer had 
 satisfied himself that he was using more coal than he should ; precisely the 
 reason he did not know, for he had no Indicator. After a good deal of 
 persuasion, he induced the manager to make a call upon us for advice. We 
 suggested the application of the Indicator; but he did not understand the 
 thing, could " not see why his engineer could not set the valves," and repeated 
 the whole train of arguments which are so often rehearsed to the man who is 
 a consulting engineer, and has any practice. He finally inquired our terms. 
 "Fifty dollars a day," we answered him, "and not more than one day at a 
 time; we must consult our other work and appointments." He thought that 
 was pretty hard; in fact, he "would not pay any man fifty dollars a day, it 
 was more than he was worth." We mildly suggested to him that there were 
 other men who could apply the Indicator, and we were perfectly willing for 
 them to have every chance. But in his case it was not sufficient to have the 
 Indicator applied ; but, as the darkey said to the surgeon, he wanted also to 
 apply the " know how," which we have been trying to learn for the past twenty 
 years. We bade him good-bye, and good-naturedly advised him to call again 
 and give us his results. A few weeks after, he called, bringing some Indicator 
 cards, and frankly confessed that while the engine had been improved some- 
 what, he was thoroughly terrified at the amount of coal it was running through. 
 He presented us with the card X A i, Fig. 71, and any one who knows 
 anything about working steam would not dream that this was made by a 
 Harris-Corliss machine. If it had been made on one of the old-fashioned, 
 grid-iron cut-offs, sliding on the back of the main valve, built thirty years ago, 
 we would have called it a pretty fair production of that style of engine ; but, 
 as to its comparison with any modern idea, it is radically deficient, and one of 
 the worst abortions we ever saw from this kind of an engine. The old 
 question then arose. We told him frankly we had quite enough to do without 
 the job ; at the same time, we liked just such a job, for it furnished food for 
 
u6 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 reflection for other people who are using steam power. But the old gentleman 
 thought the price was abominable, and went to consult his treasurer. A few 
 days after, he and his treasurer walked in with the same diagrams. A half 
 hour was spent in chatting and chaffing, and no result was reached. 
 
 In about a week, the son of the 
 agent came in, bringing the cards 
 which our expert friend had taken, 
 showing the state in which the 
 engine was left. The son was one 
 of those intelligent fellows, who not 
 only wants to know what is going 
 on, but also some good reason 
 why. We asked him if he had any 
 objection to our running our Plani- 
 meter over the card. " Certainly 
 not; he wanted information." In 
 running the Planimeter over the 
 card, X A i, we told him that he 
 was losing about 25 per cent, of his 
 power by back pressure; in other 
 words, that the back pressure was 
 abominable; that the engine was 
 largely overloaded, and that the 
 draft of steam did not allow him to 
 realize his boiler pressure; but that, 
 if he could afford to burn five tons 
 of coal to do what four tons ought 
 to do much better, it was not our 
 business, but his. We finally made 
 him a proposition, that we would 
 indicate the engine, adjust the 
 valves to suit ourselves, and be 
 responsible for results, if he would 
 agree that the engine should be let 
 alone, and we would take one-half 
 FlG - 7I - of what we could save in fuel for 
 
 thirty days' running time ; to take his last four or six months' account, and 
 average the time, and take our thirty days' run, actual weight, and let himself, 
 his father, and his engineer, make their own figures. He went away. A day 
 or two after, he accepted our proposition. We named a day, and obtained a 
 half dozen reproductions of X A i , with little variations, according to the 
 load. The engine is 23 X 60 inches, 57^ revolutions, 90 pounds of steam, 
 scale 40. Measuring from the atmospheric line, or line of rest on the instru- 
 
TWENTY YEARS WITH THE JXDICATOR. 
 
 117 
 
 merit, we get 85 pounds into the cylinder. It is hard work to tell where the 
 
 cut off is, or where the expansion line commences. There is evidently no 
 
 difficulty in telling where it ends, pr that there is a slight amount of back 
 
 pressure in the cylinder. At the commencement of the exhaust, with a 
 
 nine-inch exhaust pipe wide open 
 
 into the air, and not more than 40 
 
 feet long at that, at A, we get 25^ 
 
 pounds back pressure ; at the centre 
 
 of the stroke, we get 7^2 pounds, 
 
 and at B, we have 5 pounds left. 
 
 The engine was burning twelve and 
 
 a half tons of coal a day, of eleven 
 
 hours, developing 750 horse-power, 
 
 of which 595 horse-power was trans- 
 
 mitted, less 156 horse-power back 
 
 pressure. If our feaders will figure 
 
 this a little, they will find that the 
 
 engine was running with three 
 
 pounds of Lehigh furnace coal, or 
 
 what may be better known, per- 
 
 haps, as " broken," in pieces about 
 
 the size of a man's fist. Slightly 
 
 over 25 per cent, of the load was 
 
 thrown away. After four hours' 
 
 work, a part of which was spent in 
 
 making explanations, and several 
 
 stoppages, we produced X A 2, 
 
 which represents 470 horse-power, 
 
 nearly, and yet was driving the 
 
 same machinery as X A i. 
 
 It will be seen that X A 2 has 
 exactly 90 pounds of steam in the 
 cylinder at the impact; that the 
 point of cut off is very sharply 
 defined ; that the steam pressure, to 
 the extent of five pounds, is lost . 
 
 . , 
 
 so that we start with 90 pounds, and 
 cut off very sharply with 85 pounds. The expansion line, without applying 
 the theoretical curve, to the practiced eye, is a beauty. It must be remem- 
 bered that every pound of the mean pressure on the piston of this engine 
 gives 7.239 horse-power ; hence, 37 >< per cent, of the load by X A i is exactly 
 thrown away. Yet no heating was being done ; the engine was exhausting in 
 both cases into the open air. X A 2 shows iV 2 pounds of back pressure on 
 
n8 TWENTY YEARS WITH THE INDICATOR. 
 
 an average, commencing slightly in excess of that, and terminating the exhaust 
 by a very handsome compression, and almost absolutely correct admission. 
 
 This is a most interesting case, because it is based on absolute facts. At 
 the end of three weeks from the adjustment of the valves, the old gentleman 
 called to see what our charge was to be. We referred him to the engagement 
 made in his son's letter. A day or two afterward, the treasurer called with 
 the same question. We simply referred to our agreement, which was in 
 writing. The day before the termination of the thirty working days, the son 
 called, asking us if we expected a saving which would amount to 30 tons of 
 coal. We told him we expected a saving of over 70 tons of coal, as the total 
 amount saved, and he told us they were going to exceed that amount, he 
 thought. Here the matter was left until the thirty days terminated. The 
 account rendered, is as follows: For four months' working days, 24,783 
 pounds of fuel were used, including banking fires at night, and on Sunday, 
 under boilers sufficient to run their big fire pump. For the thirty days after 
 the readjustment, 5,140 pounds of coal were saved each day, the fuel account 
 being charged with banking the fires, and maintaining a steam pressure not 
 less than 50 pounds on four boilers every Sunday for the big fire pump. The 
 coal in the coal-house cost $6.40 per ton, making a clean saving of $16 per 
 day, saying nothing of the few pounds of coal over 2^ tons. They figured, 
 therefore, the saving, by the simple readjustment of the valves, to be $480 for 
 five weeks' running time, 66 hours per week, making thirty working days. 
 The letter received from the old gentleman a few days after, enclosing his 
 check, stated simply as follows : " Six weeks ago I would not have believed 
 that you or any other man could have shown how ignorant a man can be in 
 the use of fuel. The only thing I regret is that I had not long ago employed 
 you. If this should ever be given in the columns of your paper, do not give 
 any clew to the mill or the manager, if you have any respect for yours truly." 
 
 And yet this is not as bad as some mills are actually doing today. The 
 way out is simple, and some of our corporations, that consider an engineer is 
 getting above his business when he attempts to learn something, may perhaps 
 get down 1 j their business through their legitimate representatives, if they 
 themselves were to learn more of the Indicator, of the absolute facts which it 
 records, and of the saving which the proper reading of the simple pencil lines 
 of the instrument upon a piece of paper will allow a man practiced in it to 
 effect. Dollars and cents are the measure of most men's success, and they are 
 quite as ignorant why a man should spend years in this practice, and then ask 
 them but a very nominal sum indeed for the use of his experience, as the old 
 darkey was why the surgeon should charge $25 for fifteen minutes' work, which 
 might save a man's life, not taking into account the years he had devoted to 
 study in acquiring an intimate knowledge of human anatomy. But there are 
 people who can only learn from experience, and the case which we give here is 
 peculiarly one of these applications. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 119 
 
 LESSON XXXIII. 
 
 THE diagrams, Fig. 73, which are the subject oi this lesson, came from a 
 Reynolds-Corliss, 24 inches in diameter, 48 inches stroke, rated at 330 horse- 
 power, making 76 revolutions per minute, 40 scale (boiler pressure not given), 
 driving a cotton mill in Mississippi. This inquiry comes with them : " What do 
 you think of them, and what 
 improvements would you sug- 
 gest which will work for our 
 advantage? " 
 
 Apparently there would 
 appear to be little difference, 
 and yet the crank end, while 
 seeming to cut off the shortest, 
 is doing more work than the 
 head end. The cut off is 
 cleanest on the head end ; but, 
 after the valve is closed on the 
 crank, the steam seems to come 
 through under the valve, and 
 the expansion line is higher 
 than it should be. Remedying 
 this would be an improvement 
 which would save money to the 
 concern. The head end, if at- 
 tention is given to the vertica 
 line, will be found late in taking 
 steam. We would quicken that 
 valve slightly, by opening it a 
 trifle sooner. This would have 
 a tendency to somewhat in- 
 crease the pressure, which 
 would probably go nearer to 
 the dotted line on that end. 
 On the diagram marked C, 
 the steam line proper is very 
 short, while the cut off is 
 apparently at B. This valve, seemingly, opens quicker than the other, and, if 
 the instrument is correct, the line leans the wrong way, as it leans to the 
 vertical line rather than from it If the valve was opened slieMv 
 
 FIG. 73. 
 
120 TWENTY YEARS WITH THE INDICATOR. 
 
 and the cut-off then adjusted to do the same amount of work upon each 
 end, there is little doubt but there would be less loss in pressure than is shown 
 by the diagram. Taken all in all, the diagrams are very good, yet the engine 
 could be made to do its work with a perceptibly less amount of fuel by the 
 changes we have indicated, and, if they are made, we should be glad to see 
 other diagrams after the alteration. 
 
 At A, on each of the diagrams, it will be seen that the commencement of 
 the exhaust is abrupt, and the toe of the diagrams is square on the wrong side. 
 If the movement of the exhaust valves was slightly quickened, the dotted line, 
 D, would be produced upon that end, while E would be produced on the 
 termination of the expansion line, and the commencement of the exhaust at F. 
 Both these outlines will be produced by shortening the jim -cranks slightly, if 
 it is the ordinary Reynolds-Corliss engine. The boiler pressure in this case is 
 not given; had it been, we might have told whether further improvements 
 could have been made. It is evidently plus one hundred pounds, as nearly 
 one hundred pounds is realized in the cylinder. On the whole, it is better 
 work than the average, and speaks well both for the builder of the engine and 
 those who have it in charge. 
 
 LESSON XXXIV. 
 
 IN this lesson we have a veritable study, not exactly in natural history, 
 but in the misuse of steam. These diagrams, Fig. 74, were taken from a 
 Greene engine, and a machine capable of doing much better work than this. 
 The 'man in charge of this engine had an Indicator, but whether he did not 
 know how to use it, or did not want to, we cannot tell. The diagrams are 
 about as bad as anything can well be. C D represents vertical lines, showing 
 the boiler pressure, 55 pounds, 40 scale. If we take A, and start on the 
 admission line, we find the admission line leaning away from the vertical, and 
 this tells us conclusively that the motion of the valves is late. The steam rises 
 to i, where a sharp off-set is made, as the piston begins to move at that point. 
 The pressure then rises to 2, where another off-set is made, and very much 
 more rapid than the other. This is owing to the accelerated motion of the 
 piston. The motion of the piston is increasing in speed all this time; the 
 motion of the valve is also late in its opening, and so does not keep up with 
 
TWENTY YEARS WITH THE INDICATOR. 121 
 
 that of the piston. The motion of the piston from i to 2 is much slower than 
 from 2 to 3, hence the admission line varies less from the perpendicular from I 
 to 2 than from 2 to 3. At 3, fifty pounds pressure is utilized, and from 3 to 4 
 we may call it a steam line. At 4 the valve is closed. The expansion line 
 continues to 5, where the exhaust valve partially opens. The expansion line 
 then commences, and returns on the exhaust line, until we meet a very queer 
 character near 6. What makes this peculiar notch at that end of the diagram, 
 and in that way, we confess we are unable to explain satisfactorily. If the 
 engines had grid-iron valves for exhaust, the valves might have closed and 
 traveled past the opening again, so as to compress the steam to a point and 
 then reduce it again by admitting it into the exhaust until the valve traveled to 
 another grid. 
 
 B is, in a general way, worse than A. The exhaust valve closes at 7, 
 making a very peculiar kink. Compression taking place, the pencil of the 
 Indicator travels past 8, drops down when the piston of the engine begins to 
 
 FIG. 74. 
 
 move, and begins to travel backward, passing at 8, running up to 9, at which 
 point the piston starts on its journey, the valve opening very late ; at 10 it is 
 still later, and at 1 1 very late. The round outline of A shows that the valve 
 does not supply steam in any quantity sufficient for the area exposed. From 
 ii to 12 we may call it a steam line. From 12 on, the expansion line takes 
 place, making one of the most outrageous cards found in practice. We do 
 not know of any explanation for this appearance unless, perhaps, the engineer 
 never knew the use of the Indicator, possibly did not care to know, or else 
 that, in attempting to change the valves by the Indicator, he had got lost, and 
 this is probably the nearest to a plausible explanation we can suggest. 
 
 If we were to study this card for economy, we find that A figures 240, B 
 190, or in that proportion. Little more than half the steam, will do the work of 
 A, and considerable less than one-half the steam used at B, if properly applied. 
 Here, then, we have an engine doing its work nearly thirty per cent, more at 
 one end than at the other, and using fully double the steam that it should to 
 accomplish the work. 
 
122 TWENTY YEARS WITH THE INDICATOR. 
 
 Some parties sometimes ask questions in reference to compression. They 
 do not understand how the lines 7, 8, 9, 10 are made. Remember that the pencil 
 of the Indicator travels up and down while the motion of the paper cylinder is 
 at right angles with the pencil, or, we might say, is backward and forward, just 
 like the piston of the engine. At figure 7 the exhaust valve closes over the 
 exhaust port ; the piston has not reached the end of its stroke proportionately, 
 as the distance from 7 to the vertical line is to the whole length, C D. What- 
 ever steam is in the cylinder at the time is closed in. Now, as the piston 
 approaches the line, D, the steam in the cylinder is compressed to a greater 
 density. This compression raises the pencil of the instrument slowly, making 
 the rounded outline in this case instead of an angular one. When the piston 
 gets as far back as 8, for some reason, perhaps leaky rings or valves, or 
 condensation of steam, the pressure gradually diminishes, and, instead of 
 holding the Indicator piston up as high as 8, the change which takes place in 
 the steam reduces the pressure, and the piston of the Indicator falls downward ; 
 it reaches the lowest point, as will be seen, at the very extreme end of the 
 travel of the piston. The steam valve now commences to open, and steam is 
 let slowly into the cylinder. The piston commences to go back on its outward 
 stroke, and the steam increases in pressure, making the line up to the figure 9. 
 During the time this line is being made the speed of the piston is very slow 
 indeed, and it is just passing off the dead center. As the piston starts away it 
 gradually grows faster and faster every inch that it travels, so that when the 
 Indicator piston reaches 9, the piston of the engine has started to travel much 
 faster, and the line falls back from the vertical line, D, much more between 9 
 and 10 than between 8 and 9, and the same applies to 10 and n as greater 
 than 9 and 10. If the motion of the steam valve is late at the commencement 
 it does not open any faster, for it has no connection with the piston, and the 
 volume of the cylinder increases very rapidly. Steam should be admitted to 
 the cylinder by opening the valves when the piston is on its dead center, or 
 actual point of rest, if possible. This can be done without giving any shock 
 to the engine, or without any danger. Evidently whoever had been working 
 with this engine was either ignorant or careless. It would require an hour, 
 perhaps, to put it in first-rate order, and, with an engine not having large areas 
 of port and valve and the Greene engine is noted for this the results would 
 have been far less economical, if, indeed, there is any economy in the diagrams 
 at all. 
 
 The first thing to do in a job of this kind, in adjusting, would be to throw 
 the eccentric ahead two or three inches on the shaft, quickening all the motions. 
 Then it is a question of give and take ; perhaps one motion would have to be 
 slowed, and another one quickened a little. In a future volume in this series, 
 we purpose to take up this subject of making the alterations in an engine, and 
 give the whole series of diagrams, in order to show just what is done by 
 making a little change. We would not advise our readers, however, to imitate 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 123 
 
 the diagrams given in this lesson, upon any account, for they are worse than 
 bad, if it is possible to have them so. A good engineer would not make such 
 i diagram if he had an Indicator, and knew what it was for. If this engine 
 was doing 200 horse-power, and coal was worth $4 a ton, the proper arrange- 
 ment of the valves by the Indicator would save just about half the coal, to say 
 nothing of more regular speed and less keying up of the engine. 
 
 LESSON XXXV. 
 
 THE diagrams in this lesson were taken from the report of Henry Hiller, 
 the Chief Engineer of the National Boiler Insurance Company, of Manchester, 
 England, for 1881. It is not an uncommon occurrence, and, at the same time, 
 it is very peculiar. The cylinder is 16 inches in diameter; stroke 36 inches; 
 revolutions per minute 65; scale No. i, 22 per inch; boiler pressure 57 
 pounds. No. 2, same diameter, stroke, and revolutions as the previous one; 
 scale 12. These diagrams were taken, No. i from one cylinder, and No. 2 
 from the other cylinder of a pair working together. 
 
 l.H.P. 
 
 3.36 
 
 ATMOSPHERIC LINE 
 
 FIG. 75. 
 
 Mr. Hiller remarks as follows : " One of them was actually doing no 
 work, but was -really being driven by the other. One of the engines they 
 stopped at our suggestion, and the water consumption, as shown by the 
 diagrams, reduced from 66 pounds to 35.4 pounds per indicated horse-power 
 per hour " 
 
I2 4 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 These diagrams are peculiar in more respects than one. No. i is very 
 late in taking steam at both ends, more so at one end than the other. What- 
 ever the pattern of the engine may be, no description being given, the steam 
 would seem to be badly wire-drawn. The expansion line is a wicked one, and 
 the effective pressure differs radically between the two ends. Sixty-six pounds 
 of water per hour is an outrageous quantity. Twenty-five or six is accom- 
 plished on old-fashioned slide valve engines, and as low as thirteen to sixteen 
 by the Corliss condensing. 
 
 Diagram No. 2 is more than peculiar. The steam is admitted, cut off 
 sharply, and expanded across the atmospheric line at about one-fifth stroke. 
 That part of the diagram which is below the atmospheric line, in which the 
 
 H.P. = 2.5 
 
 IjMOSpHERtC LING. 
 
 FIG. 76. 
 
 steam is long drawn out beyond its usefulness, has an area larger than that of 
 the pressure on the piston above the atmospheric line, and it is the same at 
 both ends, although a little more difference exists in one than in the other. 
 No doubt some of our readers will get bothered in measuring this with the 
 Planimeter. They are reproduced full size, so that they may be measured. 
 The boiler pressure, in this case, is 57 pounds, while the realized steam 
 pressure is only 24 or 24^ pounds. The indicated horse-power of this pair 
 of cards is less than nothing; in other words, the horse-power is minus 2}^, 
 or, to put it into still another shape, 2^ horse-power is being developed 
 against the other engine. This is caused by the expansion of the steam, which 
 is drawn out past its useful or efficient force, so that it really retards, or would 
 retard, the action of the engine, were it not that the other side is driving so 
 much more power, and this is doing very wastefully what it is doing at ail, 
 
TWENTY YEARS WITH THE INDICATOR. 125 
 
 from the fact of the steam being admitted at a much lower pressure than in 
 the boiler, and then being expanded at such a ratio that it practically ceases to 
 be of any use. We do not wonder that, when this engine, as Mr. Hiller 
 advised, was stopped, the other engine did all the work with less fuel. The 
 measurement of the spaces, below the atmospheric line, is always taken from 
 the measurement of that space above the atmospheric line, by the action of the 
 Planimeter ; but in this case the space below the line is of the most account, 
 consequently the Planimeter gives us a negative result at the end of its travel. 
 This will be an excellent exercise for learners to practice upon, and it will give 
 them useful information in regard to taking the areas of surfaces which are 
 somewhat mixed. 
 
 If we take No. i, in this illustration, we have the fact of 38 pounds of 
 steam, out of 57 boiler pressure, being shot through the ports on to the piston 
 head, after it has been on its way some time, so that it never catches up. We 
 then have a low ratio of expansion, from the fact of wire-drawing and 
 throttling, and the steam is reduced in pressure to that extent which makes it 
 a most exorbitant consumer of water. 
 
 In No. 2, the same thing is carried out. The steam is put into the 
 cylinder of the engine to do less than any work at all, and, aside from wasting 
 ihe amount of steam which is put into the cylinder, the parties were also 
 wasting power which had to be made up by the other cylinder of the 
 machine. This is a most unique example. It is different from anything which 
 we have before had, and does not show very good economy in the use of 
 steam. We have introduced it in this place more for the purpose of giving 
 our readers practice with their Planimeters and computations, than because of 
 anything which is radically instructive. In No. 2, the dotted line produces 
 eight pounds of vacuum, or pull-back, while the other end only produces five 
 pounds at the starting point. The space of the stroke traveled by drawing the 
 ste?m, below the atmospheric line, is double, or more than the space traveled 
 by the piston before the expansion line crosses the atmospheric line ; but where 
 the space is laid out different, the Planimeter gives us a reading that both sides 
 are negative, results. The valves of engine No. 2 must have been in elegant 
 order, for they make first-class air-pumps, or would, if they had water with 
 which to condense the steam, and from which to extract the air. Taken all in 
 all, these cards are a very interesting study, and only show what can be 
 done, if parties would only try ; but we should much rather that they would 
 try on some other man's coal pile than our own. Perhaps some of our readers 
 will gather ideas from this that will set them to thinking more closely, and if 
 they will attempt to erect the theoretical curve upon either one of the diagrams 
 they will find that all new rules will give them a great deal of variance. 
 
126 TWENTY YEARS WITH THE INDICATOR. 
 
 LESSON XXXVI. 
 
 THE diagrams shown in this lesson are from a Wheelock engine, 14^ X 
 4^mches, 76 revolutions, boiler pressure 72 pounds, scale 30. The diagrams 
 
 are simultaneous, or taken at the same 
 instant of time; A the crank, B the 
 head end. The boiler pressure, in this 
 case, is 72 pounds; the Indicator ac- 
 counts for only 60 pounds upon the 
 head of the piston, or one-sixth the 
 boiler pressure does not enter the cyl- 
 inder. We know nothing of the reason. 
 The crank card, in this case, has rather 
 a neat outline, but there are radical 
 faults in it. We find the line from A 
 to C, instead of becoming concave, or 
 expanding, as steam should do, be- 
 comes convex. The dotted line shows 
 about what should occur. The cut off 
 of this diagram is clearly marked at A ; 
 there need be no guessing at it. The 
 clearance of the engine is not given, 
 hence we have nothing in particular to 
 assume. If we take the steam as it 
 probably cut off at A, the pressure 
 should immediately drop to the dotted 
 line, and follow it, or very near it, 
 instead of which we find that steam 
 actually enters after the valve is closed 
 at A, or is maintained somewhere 
 between the cut-off valve and the pis- 
 ton head. This steam either leaks in, 
 or has been fed in, we cannot say 
 which, and the dotted line gives the 
 appearance of the first part of the 
 hyperbolic curve, which is concave, 
 
 while the actual line ol the instrument is convex. The line, as erected, should 
 be much better. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 727 
 
 Diagram B is one of those peculiar features that \ve sometimes come 
 across, and is correctly stated as being a minus quantity ; in other words, B 
 does less than nothing, but rather holds back on A somewhat, and A not only 
 has to do all the work the engine 
 is doing, but has to help do what 
 B holds back. These diagrams 
 are both of full size, and exact 
 reproductions from the , original 
 cards ; therefore, our readers can 
 measure them, or run their Plani- 
 meters over them. It would be 
 interesting for them, especially 
 upon B, to see exactly where the 
 difference lies. The diagram, B, 
 shows some of the same features 
 that A does, and, while it is a 
 negative quantity, shows plainly 
 the feeding of the steam into the 
 cylinder after the valve had closed. 
 The precise reason for this we 
 cannot say probably a leak. 
 The expansion lines on these 
 cards are not perfect, and. not 
 having the clearance, we cannot 
 lay out exactly what it should be. 
 It is a self-evident fact that an ad- 
 justment of the valves would be 
 very advantageous to parties run- 
 ning the engine. We cannot 
 guess at dimensions or conditions 
 under which an engine is working, 
 and no man who is honest with 
 himself can apply exact measure- 
 ments or give the precise data 
 that shall lead to a computation 
 of the efficient work of such an FlG - 78> 
 
 engine. The diagrams are peculiar; they are not uncommon, not especially 
 as regards this engine, but diagrams even worse than this are much nearer 
 general practice. If the cut off on the head end is lengthened and the crank 
 end shortened, to even up the load, the head end will be doing something, and 
 the crank end will not have to do all the load and a little more. These 
 diagrams will bear study, analysis, and computation. 
 
128 TWENTY YEARS WITH THE INDICATOR. 
 
 LESSON XXXVII. 
 
 THE diagram in this lesson will be lull of interest to many of our readers 
 who have been following the lessons closely, and have familiarized themselves 
 somewhat with the arguments usually advanced. It is from the so-called high- 
 speed engine, 18 X 36 inches, running 92 revolutions with 90 pounds of steam, 
 
 and was sent to us by the 
 owner of the engine, asking 
 if we would tell him what 
 were the defects, and what 
 the percentages of useful ef- 
 fect. The defects are of the 
 class usually found in en- 
 gines where people build 
 them without taking advan- 
 tage of knowledge gained 
 by experience and practice. 
 The line, A B, is the vacuum 
 line ; A C, the line of boiler 
 pressure, as well as the boun- 
 dary of the clearance ; C D 
 is the boiler pressure ; E F is 
 the realized pressure in the 
 cylinder; F G the line of 
 cylinder pressure; H I is 
 the theoretical curve erected 
 from the point of actual cut 
 off, or the time the valve 
 really closes in its stroke. 
 The distance between the 
 lines, A C and E F, desig- 
 nated by the letter M, is the 
 clearance of the engine from 
 actual computation, and is 
 F1G ' 79 ' enormous. We have here a 
 
 rather curious specimen of diagram. The compression is very large, as it 
 commences before the piston on its return stroke reaches K. After the 
 compression is finished, the motion of the steam valve is somewhat late, and 
 the jog, or notch, near the letter F, shows that steam is not promptly admitt 
 
TWENTY YEARS WITH THE INDICATOR. 129 
 
 * 
 in full volume. It almost immediately falls off again, and the difference 
 
 between the perceptible closing of the valve, and the real closing of the valve, 
 amounts to more than two inches, and the maximum amount of steam 
 admitted into the cylinder is 69 pounds. But this is not the worst feature. 
 After the cut-off valve closes there would seem to be, between the valve and 
 the piston, a large amount of steam, or else the valve is leaking badly. This 
 will be found by the expansion line which, at I, is 6 pounds above the line of 
 theoretical expansion. This engine does not approximate good practice 
 anywhere, and even in the exhaust, which is through only 40 feet of pipe into 
 the open air, it will be found that there are 3^ to 6 pounds of back pressure. 
 Among other inquiries was, "What is the percentage of useful effect?" In 
 erecting the theoretical curve, we have given the engine all the benefit of the 
 doubt, and have placed the point of cut off at H, on the line, F G, which is as 
 nearly as possible to the absolute point of cut off. We have here 69 pounds 
 of steam cut off at -f^- of the stroke. The Indicator lines give us, by the 
 Planimeter, 2.48, while the theoretical curve, with the direct point of cut off, 
 gives us 2.22, giving us ten per cent, leakage of the valve, and ten per cent, of 
 the total amount of steam used is sifted through the valve after it is closed. 
 Now we use 69 pounds of steam in the cylinder, by the Indicator. We had 
 90 pounds in the boiler and 89 pounds in the steam chest. Giving the engine 
 the benefit of good practice, and calling for only 95 per cent, of the boiler 
 pressure in the cylinder, we should have 85^ pounds by the Indicator, instead 
 of 69 ; therefore, the effective value of the engine is 80 per cent, of boiler 
 pressure. The engine cuts off at -f^- of the stroke. If the full boiler pressure, 
 was used, or, say 95 per cent, of it, as is the case with all good engines, instead 
 of cutting off at -fg? it would cut off at T 2 ^ 7 of the stroke. This is further 
 proved by the fact that the track of the Indicator, on the diagram gives, by 
 the Planimeter, 2.48, the theoretical curve 2.22, and cutting off at -j^-, 2.38, 
 with the Planimeter, allowing the same fault of compression and back pressure 
 which now exists. Hence, if we could get the full boiler pressure, 85^ 
 pounds, into the cylinders, we should save 27^ per cent, of the steam at 
 each end of each stroke, or over one-quarter of all the steam used, by this 
 simple saving alone. This grade of expansion would, no doubt, yield higher 
 than 27-j 1 Q- per cent., from the fact of there being more loss by wire-drawing 
 of the steam to 69 pounds than there would be by doing the same load by the 
 full boiler pressure, 85}^ pounds. Therefore, to answer the question which is 
 asked us, " What is the effective value of this engine ? " it is lessened 20 per 
 cent, in boiler pressure, 1 2 per cent, by leakage of the valve, and 27 per cent, 
 in the amount of steam used, if it could do the work at 95 per cent, of the 
 boiler pressure ; and the actual value of the engine, as an actual transmitter 
 of power or consumer of steam, is less than 50 per cent, that of a first-class, 
 modern-built engine, working upon principles which are every day practiced 
 in New England by the best builders. In all this computation we take the 
 
130 TWENTY YEARS WITH THE INDICATOR. 
 
 steam in the boiler at one hundred per cent. This is no doubt a general 
 arrangement, and those parties who have little or no faith in the Indicator can 
 submit this to any engine builder who has any reputation for first-class work, 
 and they will find it precisely as we state. The line, K, shows the volume of 
 the steam which would be used at boiler pressure, while F H is the amount 
 used at the reduced pressure. The line, L, is simply an extension in order to 
 carry out the curve a little further and see precisely where it would strike. 
 
 LESSON XXXVIII. 
 
 IT is really refreshing to turn from bad engineering, such as we have illus- 
 trated in some of our previous lessons, to an approximatively good practice, 
 where preferences and prejudices have been laid aside and ignorance is 
 ignored. We have just this kind of a case in this lesson. The diagram which 
 is shown is from an engine 24 inches by 48, running 58}^ revolutions, 55 
 pounds boiler pressure, taken in actual work, and not for the purpose of 
 exhibition. This engine was built by C. H. Brown & Co., of Fitchburg, 
 Mass., and it may properly be said that Mr. Brown is one of the few engine 
 builders in this country who has adopted the Indicator as his standard to work 
 from and to work toward. In other words, if his Indicator tells him his ports 
 are too small, and the throw of his valves is not right, he has had the good 
 sense to adopt that as his standard, and endeavor to attain all that the Indi- 
 cator suggests. This diagram (Fig. 80) shows the result of his approaches. 
 
 The compression in this engine is easy, and gives a graceful line; the 
 steam valve opens as the compression ends, and fills the cylinder without there 
 being any hitch in the line. When the piston starts on its stroke, steam is 
 carried for a little period of time at full boiler pressure, then it commences to 
 fall off a trifle, as at B ; from B to C it falls nearly two pounds. The reason 
 of this is found in the fact that when the piston starts from the dead center on 
 the crank, or from the very commencement of its stroke, its motion is very 
 slow; after it has proceeded a very short distance, the speed is decidedly 
 accelerated, and the pressure is slightly reduced, a little, indeed, but in 
 practical working it is of no possible consequence, either as to perfection or 
 economy. When the valve closes the line is distinctly formed, and we know 
 just where to figure in attempting to work for the quantity of steam consumed 
 
TWENTY YEARS WITH THE INDICATOR. 131 
 
 or to lay out the theoretical curve. The corner of this is not rounded off like 
 the circle made by a coach-and-four in making a turn. We can put our finger 
 definitely upon the very point where the valve commenced to close, and where 
 it did close, there is no guess-work or assumption, and we do not have to 
 begin backward or at the end of the expansion curve and guess that the valve 
 did not leak, or suppose that the steam did not do something else. 
 
 The line, A, is drawn slightly above 
 boiler pressure, in order that it may not 
 merge into the steam line proper; and 
 when we say that 98^ per cent, of the 
 boiler pressure is admitted into the cylin- 
 der, we only state a simple fact, and one 
 which our readers, who have been working 
 with 60, 70, or 80 per cent, of the boiler 
 pressure, will not be slow to put its proper 
 value on. The expansion line of this card 
 is very fine ; its exhaust is as near perfect 
 as we need to expect, and, taken all in all, 
 it is certainly a model card. We do not 
 know the clearance of the engine, or we 
 would have elaborated it somewhat. When 
 dealing with this subject, however, we pre- 
 fer to have the absolute fact of the clearance 
 either from measurement or the builder's 
 plan, and sometimes we take pains to 
 corroborate the builder's estimate from the 
 measurement. This card was taken from 
 one of a pair of engines while it was at 
 work in the middle of the day,. with no 
 preparation or readjustment of valves, for 
 the purpose of ascertaining, more than 
 anything else, how near it approached to 
 boiler pressure. The experiment was after- 
 ward conducted by making vertical lines 
 with the Indicator, and then taking a dia- 
 gram across these lines to ascertain whether 
 the Indicator, the steam gauge, and the 
 
 cylinder pressure agreed. The pressure in the cylinder with this experiment 
 covered the top of the vertical lines by the steam line at a slightly lower 
 pressure than the one shown, so perfectly as to make complete union by the 
 steam lines crossing the very end of the vertical line while the Indicator 
 cylinder was at rest. This engine has been running some two years and it is 
 under the care of an engineer who takes good care to adjust the valves of his 
 
i 3 2 TWENTY YEARS WITH THE INDICATOR. 
 
 engine with his own Indicator, and he believes that the nearer to perfection 
 he can bring it, the nearer he is doing his duty by his employer, and parties 
 visiting his engine room will find things as nice and clean as though he was in 
 a library rather than an engine room. Oil and gurry are not found burnt on 
 to his engine, the brass and nickel work are as bright as a new looking-glass, 
 and the owner of the engine finds that it costs less to employ a first-class man, 
 when all things are taken into account, than it does to employ what are 
 frequently spoken of as tramps. There is economy in this card, as well as 
 perfection, and if those of our readers who are interested will figure it care- 
 fully, they will find that the figures run up into the nineties all round. 
 
 LESSON XXXIX. 
 
 WE are frequently shown cards from the Indicator which develop most 
 astounding approximations to the theoretical value of steam, but the best way 
 to get at this practically is to take cards or diagrams from the every-day 
 working of the machine, and then ascertain whether the machine, in its every- 
 day work, can and will do what these expert or scientific builders frequently 
 assert they can do. Having this thing in mind, we have taken the card, 
 which is the subject of this sketch, out of a complete set, which were not 
 taken for adjustment of valves, or for any other especial purpose beyond that 
 of ascertaining the precise condition of the engine. It is from one of a pair 
 of large Corliss engines, now working in Fall River. The size is 28 X 60, 54 
 revolutions, 40 scale, boiler pressure 87 pounds by the gauge. The line, A, is 
 the atmospheric line of the instrument; B, actual vacuum ; C, boiler pressure, 
 including actual vacuum ; D, boiler pressure ; E, end of the stroke, or what 
 should be the admission line ; F, the long dotted line, the theoretical curve 
 from the actual point of cut off, as seen on the card ; G, fine dotted line, the 
 actual line of the instrument. The admission line plainly shows that the valve 
 does not open early enough, and, as a matter of fact, nearly two inches, after 
 the piston has begun on its stroke, is accomplished before the valve is wide 
 open. The steam line, therefore, falls away from the actual boiler pressure 3^ 
 pounds. We have no data to say how far the steam travels from the boilers. 
 The cut off is very sharp, and the expansion line is very good. It will be 
 noticed that our cut off point, as taken from the instrument, should have been 
 carried a little farther on the stroke. We have assumed it a trifle longer than 
 it really is, but taking this for data, in all the computations which follow, is a 
 
TWENTY YEARS WITH THE INDICATOR. 133 
 
 little against the engine rather than in its favor, taking absolute facts, from 
 which our computations are made. 
 
 The exhaust valve of this engine does not open as early as it should, by 
 fully two inches of the stroke of the engine ; it does not open early enough, 
 and the condenser, therefore, 
 does not obtain the amount of 
 vacuum it should and will do if 
 they will open it early enough. 
 At the other end of the stroke 
 there is very little compression 
 indeed, in fact, none of any 
 amount, and opening the ex- 
 haust valve earlier, allowing the 
 condenser to do its work more 
 efficiently, would make com- 
 pression at the end of the 
 stroke, which would be favoring 
 the engine, and compression 
 can be obtained on a condens- 
 ing engine, notwithstanding 
 statements to the contrary by 
 men who style themselves ex- 
 perts or engine builders. 
 
 The distance between the 
 lines, C and E, is the actual 
 measure of the clearance of that 
 end of the cylinder from which 
 this card was taken ; the volume 
 of space, including both valve 
 ports, amounts to 1.71 inches; 
 in our figures we have included 
 the clearance of the engine. 
 The clearance, and the distance 
 
 which steam is carried, amounts to T 2 T \ of the whole stroke. The Planimeter 
 gives us, including the boiler pressure, the full space of the theoretical curve, 
 an absolutely perfect vacuum, and a compression of one-tenth the stroke, not 
 including the clearance, 444. The actual line denned by the Indicator, gives 
 us 388, or 87.4 per cent, of the theoretical, including all the outs or bad features 
 of the diagram. If the engine took its steam properly, and exhausted prop- 
 erly, there is no difficulty whatever in making this engine do 92 to 94 per cent, 
 of the theoretical, and doing it -from the coal-pile, and not from any one's ideas. 
 If the engine took steam quicker, we should save the area between the lines, 
 E, and the admission line or fine dotted line, and this would shorten the space 
 
134 TWENTY YEARS WITH THE INDICATOR. 
 
 which steam is carried, so that, instead of being ^f^, it would probably run 
 down to 22 or 23, and the very fact of opening this valve earlier would allow 
 more steam to enter this cylinder, and would give us nearer actual boiler 
 pressure ; hence the displacement of the steam valve of the engine is working 
 decidedly against its economy. If the exhaust valve opened earlier, the con- 
 denser could do its work better, because it would take the bulk of the steam 
 quicker, and would make a more effective vacuum or a nearer approach to 
 complete vacuum. Therefore, when we say the engine is doing 87.4 per cent. 
 of the theoretical, we do not say that the engine is doing all that it will or all 
 that it can ; but, taking the card precisely as it came from the Indicator, and 
 just as the engineer was running the engine, in the face of very apparent dis- 
 advantages, which could and ought to be remedied by the proper application 
 of the Indicator, it is then doing almost 90 per cent, of the theoretical. In 
 doing this, the displacement of the steam valve loses 3^ pounds boiler 
 pressure, the condenser gives us 108 or no, while in the theoretical we figure 
 150 to 155, the condenser only doing 75 per cent, of the theoretical this in 
 the total figures against the engine. If we take the high pressure part of the 
 diagram, and suppose the engine would exhaust as these engines usually do, 
 we should have 88^ per cent, actually developed by Planimeter measurement. 
 The steam valve of the engine should be quickened considerably, and the 
 exhaust valve quickened also ; this means moving the eccentric ahead on the 
 shaft from an inch to an inch and a quarter ; then perhaps the jim-cranks may 
 have to be lengthened or shortened, as the case may be, in order to bring the 
 other valves up to time. There is a point where half a turn on the jim -crank, 
 or a quarter of an inch on the eccentric forward or back, makes a radical 
 difference. Eighty-two pounds in the cylinder, with 87 in the boiler, and the 
 steam valve opening two inches behind the piston, is a better showing than a 
 great many engines make. 
 
 The man running this engine should open his steam valve so that it would 
 touch the line, E, where the dotted portion is at the bottom, quite up until the 
 steam line is commenced. These changes are simple, and, with the Indicator 
 can be readily made. Where the point of cut off is so thoroughly defined, as 
 in this case, there is no difficulty whatever in following the lines from the point 
 of cut off, not from the termination of the expansion line. 
 
 This, as are all our diagrams, is exactly full size, and can be measured and 
 worked from by any of our readers who are so disposed. This will be 
 interesting for them ; it is good practice ; it deals only in facts, and it will show 
 them how to apply the rules, which any one can do, and how to ascertain 
 whether the engine does what the builder represents, especially where they are 
 loud in decrying well-established precedents by other builders. Facts are not 
 always agreeable, but they are the best things in the world from which to 
 obtain information, and they sometimes take the conceit out of people, even 
 if at considerable cost, and are to sensible men invaluable. 
 
TWENTY YEARS WITH THE INDICATOR. 135 
 
 LESSON XL. 
 
 As a fitting close to the practical lessons embodied in this volume, we 
 introduce one of the most radical departures in steam engineering, and one of 
 the most successful of the almost numberless candidates working in the direc- 
 tion of high speed. This engine is, to a certain extent, an anomaly, and 
 in Volume II., which will complete this work, we hope to embody the 
 valves and valve motion, and the regulator with its full line of action, so that 
 our readers, who do not become discouraged in this volume, can gather from 
 them what has been attained by a careful keeping in view of the theoretical 
 value of steam after it is made, and the practical working out of the largest 
 percentage of that theoretical value, which has, as yet, we believe, been attained 
 by any high speed engine. 
 
 Figs. 82, 83, and 84, were all taken from the Armington & Sims engine, 
 on the same day, under varying conditions. The size of the engine was 9^ 
 inches diameter of piston, 12 inches stroke, 300 revolutions per minute, 
 boiler pressure varying from 85 to 82 pounds, scale 60. 
 
 FIG. 82. 
 
 Diagram A represents the engine as working at 80 horse-power indicated, 
 with an average pressure of 56.51 pounds. The admission line is almost 
 absolutely perfect. There is a trifling variation, probably caused by the piston 
 of the Indicator. The steam line is simply perfect, cutting off at a. The 
 expansion line, under such a speed, is slightly waved ; and this, without doubt, 
 is somewhat owing to the intensity in the action of steam and the impulse of 
 the momentum of the Indicator. The variations are, however, very slight, 
 when the speed is considered, and the mechanical perfection required both in 
 the valves of the engine and in the piston of the Indicator. The release, at &,' 
 approximates closely to locomotive practice; the commencement of the 
 exhaust, at , shows a back pressure of between one and two pounds at the 
 commencement, and about one pound at the termination. The cushion, or 
 compression, on this engine, owing to its very high speed, is not precisely of 
 
136 TWENTY YEARS WITH THE INDICATOR. 
 
 the same character as in the slower moving engine, the line being somewhat 
 irregular. The peculiar points of this diagram will be noticeable by every 
 steam engineer when he considers that it was completed in one-tenth of one 
 second while running at regular speed. This diagram, taken all in all, is one 
 which embodies a very high economy with an almost perfect regulation. 
 
 Diagram B is the same engine precisely, developing 52.08 horse-power, 
 with an average pressure of 36.83 pounds. In this case we have not lost any 
 of the beauty of the steam or admission lines. As in diagram A, the expan- 
 sion line has a somewhat more wavy appearance, the release commences 
 almost at the same point, if anything, a trifle earlier, and the compression 
 being comparatively earlier, coinciding with the release. Diagram A has 85 
 pounds boiler pressure, and 81 pounds by the Indicator in the cylinder. 
 Diagram B has 85 pounds boiler pressure, and 82 pounds in the cylinder, 
 while diagram C has 80 pounds in the cylinder, with an indicated horse-power 
 of 11.78, and a mean pressure of 8.33 pounds. 
 
 Parties who will study these three diagrams will see that the release and 
 compression vary materially, and on these points it is well to say that this is 
 the first engine we have ever noticed which worked steam according to the 
 theory of expansion and compression, as approaching most nearly the produc- 
 tion of the largest amount of utilized units of heat from the steam ; in other 
 words, the regulator and valve motion of this engine are so arranged that the 
 valve has an absolutely constant motion, with reference to giving the engine 
 steam, but every other position of the valve is variable according to the load, 
 and in the case of release and compression, these two important and often 
 overlooked points are, by the inventors and builders of this engine, made to 
 vary inversely as to the load. 
 
 Diagram C gives us the nearest approximation to what our old friend, 
 Prof. Thurston, of the Stevens Institute of Technology, has long argued was 
 the correct way of working steam ; that is, that steam at a certain pressure 
 and temperature should be expanded that number of times which would make 
 it most efficient, and which, without any exhaust, could be compressed on the 
 return stroke, making another line lower in utilic effect than the first, and 
 needing only a small amount of steam to make it do the second and each 
 
TWENTY YEARS WITH THE INDICATOR. 137 
 
 successive stroke. Armington & Sims, in this case, have so arranged the 
 motions of their valves that the load upon the engine varies the amount of 
 steam admitted, and the amount of the load governs the release and exhaust 
 inversely ; that is, in opposition to the regular proportion, the greater the load 
 the later release and compression ; the lighter the load, the earlier release and 
 compression ; hence, we have, in diagram C, a release somewhere about plus 
 one-half the stroke, and a compression of slightly minus one-half the stroke. 
 By this mode of compression one of the greatest antagonisms to the success 
 of high speed, in practice, has been overcome ; that is, the loss of steam and 
 the expense of maintaining a large clearance. 
 
 Diagram C, it will be seen, compresses 56 pounds ; the steam valve then 
 opens and the admission and steam lines are almost at absolutely right angles 
 to each other. The larger the load the later the release and compression, but 
 the engine exhausts freely up to that load, which is the maximum ; and when 
 
 FIG. 84. 
 
 the engine is running almost without load, the release and compression are so 
 arranged that no thumping or jar occurs to the machine. This is the highest 
 attainment toward working steam expansively. It is done by a single piston 
 valve controlled by a variable regulator, the engine furnishing the power, the 
 regulator changing its movements according to the increase or decrease of the 
 load, varying from ten to eighty horse-power on perhaps three strokes of the 
 engine without making a change of more than three or four revolutions, or 
 affecting the speed for more than one-half to three-quarters of a second. 
 These diagrams will bear a great amount of study, and practical engineers 
 cannot fail to admire them. 
 
138 TWENTY YEARS WITH THE INDICATOR. 
 
 LESSON XLI. 
 
 DEMONSTRATING THE ACTUAL POINT OF CUT-OFF FROM THE STEAM 
 USED, WITHOUT REGARD TO TERMINAL PRESSURE OR LACK 
 OF DISTINCTNESS IN THE CUT-OFF LINE. 
 
 In our own experience, we have frequently been unable to determine the 
 point of cut-off with sufficient accuracy or reliability, wherever the line of the 
 diagram was not clearly denned, and this oftentimes becomes necessary in 
 making computations, or in comparing one engine with another for efficiency. 
 It was, therefore, after considerable investigation, that we adopted the 
 method first published by the writer, September 15th, 1883, as a method 
 of demonstrating the positive point at which steam is cut off, or a point 
 on the line of initial pressure equal to cutting off steam at a particular 
 point, even where a leak had occurred, or where steam had drifted past the 
 steam valve after it was supposed to be closed. At that time we used the 
 following expression : " We have, therefore, stolen a march on volume two of 
 Twenty Years with the Indicator, by showing the mathematically correct 
 way of demonstrating the positive point at which the steam is cut off, or a 
 point which is equal to the cutting off of the steam at some especial or 
 particular point whenever steam leaks or drifts in." 
 
 Since this statement was made, this method has been examined by some 
 of the best mathematicians, and has been pronounced correct. It will be 
 referred to in the following lessons in this volume as the demonstration or 
 our demonstration. We reproduce the original diagrams, now in our pos- 
 session, which were published with this first demonstration. 
 
 It has been customary in years past for builders of engines, engineers 
 and experts to erect then* comparison from the " axis of the hyperbola," or 
 from the terminal pressure. " The axis of the hyperbola " is an indefinite, 
 uncertain quantity, and the terminal pressure is as apt to be wrong as right, 
 and we wish to impress upon the reader of this, that in this case we divide 
 the problem into two different and distinct demonstrations ; first, we locate the 
 exact point of cut-off on the line of initial or realized pressure in the cylinder, 
 from a point a little past or "at the center of the expansion line of the diagram. 
 The reason why we do this is that at or a little past the center of the expan- 
 sion line, the steam has become more settled in its action, is less liable to 
 irregular pressure, the speed of the piston is nearer constant, and the load 
 affects least either the piston or the crank in overcoming the resistance, on 
 the same principle that a train of cars, after in motion, gives a better idea of 
 the actual load than when starting or stopping them. This point, wherever 
 located, is termed the base line of the demonstration. This method is 
 founded upon the principle that if the pressure at a given point is known, 
 
TWENTY YEARS WITH THE INDICATOR. 139 
 
 and if steam does expand somewhere near Mariotte's law, then it becomes a 
 mathematical problem, and, if we know the pressure at a certain point, we can 
 lay out, by the means to be explained, the precise point at which a known 
 initial pressure of steam should be cut off to realize the pressure denoted by 
 the base line wherever it is located. This is the whole theory and it has been 
 reduced to practice in so many different forms of diagrams, at so many dif- 
 ferent points of cut-off, under so many different pressures, and with such a 
 variety of types of engines, that the best authorities in several of our insti- 
 tutions of learning have adopted it, and have pronounced it mathematically 
 correct. We do not mean to go into mathematics to any extent, and shall, 
 therefore, refer our readers to the various diagrams illustrated in this volume, 
 which are founded upon this demonstration, and which embrace a large range 
 of different types of engines at all sorts of speed, under all differences of 
 pressure, and that the comparisons made are actual rather than visionary. 
 
 Very frequently, as in one of the first examples given in this lesson, we 
 have found the apparent or visible cut-off, on the diagram as made by the 
 instrument, to vary materially from the demonstrated line. To explain this 
 briefly, it frequently occurs that the valve does not seat itself, or that some 
 disturbance occurs in its action, so that after it is apparently closed and the 
 expansion line has been commenced, that a quantity of steam drifts into the 
 cylinder, so that the indicator does not make a true expansion line from the 
 quantity of steam shown by the visible point of cut-off, and this method 
 shows us precisely the amount of steam wasted as between visible and 
 demonstrated points of cut-off. We have never yet found an engine with this 
 demonstration where the actual line of the indicator overran in amount of 
 work yielded, the theoretical line drawn from the point of cut-off from the 
 demonstration. 
 
 Another point for the reader which may be asked, we will anticipate. It 
 is frequently necessary (in his mind only, however,) to know precisely the 
 amount of clearance to an engine, in order to know exactly the use of the 
 steam. With this method of demonstration the clearance becomes unnecessary 
 so far as the demonstration goes ; it is very important, however, if we are 
 figuring the diagram for economy in water, to know the clearance, but so far 
 as the action of steam goes, and the reliability of the demonstration based on 
 that action, the clearance is an unnecessary quantity. We are dealing with 
 the steam after the expansion takes place, it shows us what the valves do and 
 shows it correctly, but if we are to get at the actual amount of steam used, in 
 every instance, we must then learn the clearance of the engine and add a pro- 
 portionate length to the amount of steam used ; but these two elements are 
 not of necessity identified with each other so that the clearance need to be 
 taken into account in the demonstration. 
 
 Fig, 96 is taken from a Corliss engine, which has been running many 
 years. To explain our demonstration, we first of all draw the line of initial 
 pressure C, then the line of absolute vacuum D, the vertical line B, which in 
 this case represents the clearance of the engine. We have now actually 
 known factors. Now, at some point in the expansion line, in this case at the 
 
140 
 
 TWENTY YE ARK WITH THE INDICATOR. 
 
 crossing of the expansion line with the line of rest of the instrument, we 
 draw the vertical line A ; this is also a known quantity ; it is the actual press- 
 ure in the cylinder above the vacuum line, it is, therefore, a known quantity. 
 There is no especial reason why we locate it at this particular point in the 
 stroke, only at that point the line is entirely settled in its work. 
 
 Now, from the intersection of A, D, we draw the angular line E, which 
 connects the base of A with the intersection of B, C, at the point represent- 
 ing the clearance of the engine added to the diagram and the initial pressure. 
 This line is for the purpose of demonstration ; now we wish to obtain a 
 parallel line to the one just erected ; measure the distance from A to the line 
 just erected on the atmospheric line, as in this case the top of the. line A 
 intersects with the atmospheric line ; lay off this distance A, E, on C which 
 gives the distance F, I ; lay off the same distance on the line D, which gives 
 us D, K, or from the base line A to the new line K, F. F is, therefore, the 
 
 FIG. 96. 
 
 point at which the initial pressure of steam should have been cut off to have 
 given the pressure A at that point in the expansion line. It will be seen that 
 the fact and the demonstration do not agree apparently. This is the end of 
 the demonstration practically. Now, if we compare results, we find that the 
 lines of the indicator diagrams, as left by the instrument, show a very much 
 shorter cut-off than the line F. But, at the point J, the theoretical curve 
 dropped from the line F, joins with the actual line of the instrument, and 
 from the point J the theoretical and the actual run on together. After the 
 valve in the engine closes, an amount of steam passed through under it and 
 was carried into the cylinder, and the amount of steam increased after the 
 cut-off was shown by the indicator to equal the amount shown by the shaded 
 portion of the diagram, between the actual line of the instrument and the 
 theoretical line dropped from F, continuing H, J, or about twenty per cent. 
 The point F represents the point of cut-off equaling the actual amount of 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 141 
 
 steam put into the cylinder, taking the whole diagram into account as demon- 
 strated. The steam drifted into the cylinder from the time the cut-off valve 
 was apparently closed, as shown by the indicator, up to that point in the 
 stroke represented by J, where the leakage stopped, the valve then had be- 
 come positively closed and no more steam was admitted. 
 
 It may be remarked that, after this demonstration had been published, 
 the agent of the mill from whose engine this diagram was taken was written 
 to, asking him if he would examine his engine to see whether the valve on the 
 head end was leaking or not. His answer was : 
 
 Yours of- 
 
 -receivecl : contents noted. I removed the cylinder 
 
 head last night, and found a bad leak in the steam valve." 
 
 In contrast to this, we introduce Fig. 97, taken from the Pullman engine 
 at the Pullman Car Works, near Chicago; the same engine which was 
 exhibited at the Philadelphia Exhibition in 1876, by Geo. H. Corliss. 
 
 In this case we erect first the line of initial 
 
 pressure, then the vacuum line. In this case the 
 clearance is not known, and in contrast with 
 Fig. 96 we make our base line, A, below the at- 
 mospheric line. The demonstration is then made 
 precisely as in the former case, with the result 
 that the motion of the valve in this case is a trifle 
 slow as compared to the stroke, and the visible 
 and actual points of cut-off vary slightly, but 
 come together at the point J, which in this case 
 is much nearer the commencement of the stroke. 
 
 FIG. 97. 
 
 The actual and theoretical then run along almost identically. It will be noticed 
 that there is nothing assumed in this case, and if the demonstration is care- 
 fully made, which anyone can do with a pair of triangles, you will get 
 positive results. F, I, in this case represent the amount of steam introduced 
 into the cylinder. The expansion line runs considerably below the atmos- 
 pheric line, and the vacuum line is almost a perfect line, there being no 
 compression. The admission line is parallel to the vertical by its side, but 
 the opening valve is a very trifle late ; or, we might say properly, is a trifle 
 slow in its motion, so that a very slight diminution of pressure is observed. 
 The convexity at H in this diagram is caused by a slight leak in the valve 
 when it seats. It must be borne in mind at this time that the expansion is 
 
142 TWENTY YEARS WITH THE INDICATOR. 
 
 in a very rapid ratio, and when J, the expansion line, has been reached, the valve 
 is seated and not another particle of steam obtains access into the cylinder. 
 During the time of this leak, which is insignificant, the engine makes but 
 trifling progress in its stroke. From the point J to the termination of the 
 expansion line, there is a variation of less than one-fifth of one per cent, from 
 the theoretical, taking into account the realized boiler pressure there is a loss 
 of 1.7 per cent. This engine is, therefore, realizing 98.3 per cent, of the 
 theoretical, taking realized steam pressure as the unity. 
 
 In these two diagrams we have avoided any confusion of lines in laying 
 out the theoretical curve. That method will be explained in the following 
 diagrams, and if the readers of this will follow the different examples, show- 
 ing the adaptation of this demonstration, they cannot fail, we believe, to 
 become as proficient and as careful in the application of the demonstration 
 and the theoretical curve, as anyone need to be for all practical purposes. By 
 this method of demonstration we show, in the case of Fig. 97, 98 per cent, 
 plus, while in Fig. 96 we show a little less than 80 per cent, of the theoretical. 
 Either of these diagrams, without any demonstration upon them, make a fine- 
 looking curve; it shows, therefore, that the application of some system of 
 demonstration with a basis of fact, will give us what we are studying the 
 indicator for actual information with regard to some thorough and reliable 
 test, to ascertain whether the diagrams, after taken, if good-looking, shall 
 give us practical results, showing an economy in the use of steam as well as 
 a pleasing appearance by comparison. 
 
 To embody the whole matter for reference, we give the following 
 
 DIRECTIONS FOR MAKING THE DEMONSTRATION. 
 
 Take any indicator diagram, lay out upon it the absolute vacuum line 
 with the scale that the diagram was taken with. Then lay out the initial or 
 realized pressure in the cylinders ; these two lines will, of course, be parallel. 
 Then connect these two lines at the admission end of the diagram by a verti- 
 cal line at right angles to the two horizontals already laid down. If the 
 clearance is known, this line may include it, otherwise erect it simply the 
 width of a line away from any portion of the admission line ; but this may be 
 varied somewhat ; if the engine takes steam too early or too late, let the 
 vertical line barely be outside of the extreme point covered by the line of the 
 indicator. Now, from some point on the expansion line near the center, if 
 anything,. a little beyond, erect the base line from the actual line of the 
 indicator to the absolute vacuum line, and be careful to have it at right angles 
 to the vacuum line. From the intersection of this line with the vacuum line, 
 draw a diagonal to the intersection of the steam pressure and vertical line. 
 Now, by means of a triangle lay off a right-angled line from the top of the 
 base line, or its intersection with the expansion line of the diagram, until it 
 intersects with the diagonal line just drawn. The purpose of this line is to 
 measure carefully, with a pair of dividers or otherwise, the distance from the 
 top of the base line to the diagonal, so that this distance may be transferred 
 
TWENTY YEARS WITH THE INDICATOR. 143 
 
 both to the vacuum line and the steam pressure line, as the exact points 
 from which to draw the parallel diagonal, and this parallel diagonal line must in 
 every instance, and will if properly done, pass by the exact top of the base 
 line at the point of its intersection with the expansion line of the instrument. 
 "Wherever this line, the last diagonal, touches the line of steam pressure, from 
 that point drop a perpendicular to the vacuum line. You have now the 
 precise point of cut-off from the pressure at the base line, or first line 
 erected. 
 
 These instructions apply to the low pressure, condensing, compound 
 locomotive, marine or any other indicator diagram, whether taken from 
 steam, water, air, gas, so far as we have ever been able to prove it. This rule 
 has been given to familiarize the reader, and without any letters of reference, 
 so that the principles may be thoroughly understood. The mathematical 
 demonstration is not necessary, we think, from the explanation which has 
 preceded it. The clearance should always be used in demonstration to in- 
 sure correct results, whether for simple cut-off or any computation; it makes 
 a certainty, and is little trouble, compared to accuracy of result. 
 
 LESSON XLH. 
 
 DEMONSTRATION OF THE POINT OF CUT-OFF, AND HOW TO LAY OUT 
 THE THEORETICAL CURVE. 
 
 Fig. 98 is an interesting diagram in many respects, and only shows what 
 the general tendency is among steam users by overloading their engines. 
 The data with this diagram is 17 inches diameter, 36 inches stroke, 57 revolu- 
 tions per minute, boiler pressure 70, scale 30. A is the absolute vacuum ; B, 
 highest realized pressure in the cylinder ; C, vertical line being nominally to 
 represent the end of the stroke, clearance not included in this case. 
 
 Having surrounded the diagram by a parallelogram, we commence by 
 drawing the line D, which represents the pressure of steam above absolute 
 vacuum at that point of 63^ pounds From the intersection of A D, E is 
 drawn to the intersection of C B. Now, from the top of the line D, draw at 
 right angles the dotted line J, connecting D E ; the distance from one end to 
 the other of J is the distance to be laid off on the line B, as well as A for the 
 parallel line, F. From the intersection of F B we drop G, and the length 
 of the line, B, from C to G, is the volume of the cylinder filled with steam at 
 the initial pressure, which should be cut off at the point G on B to produce 
 the pressure, D, on the expansion line. This finishes the demonstration of the 
 point of cut-off. 
 
i 4 4 TWENTY YEARS WITH THE INDICATOR. 
 
 We wish now to erect from this data already obtained the theoretical 
 curve, in order to ascertain whether the expansion line of the engine approxi- 
 mates closely or otherwise to the theoretical line. We repeat here the 
 method given in Volume I, and shall endeavor to explain it so fully that no 
 reference to Volume I will be required. We commence at the intersection 
 of A C, drawing the radial lines, and to prevent confusion, we have used 
 numerals rather than letters in this figure. These lines are drawn from the 
 point K on the intersection of A C. In erecting the theoretical curve, the 
 base of our computation must always be absolute vacuum. While this differs 
 somewhat in barometrical range, it is exceedingly small, and for the moment 
 we assume it at 14.7. We draw the lines, 1 from K to G, and the line 2 from 
 K to the end of the line B, covering the very end of the diagram. Now, 
 between these two lines, 1, 2, on B, we drop the ordinates at right angles to 
 B, a little below the expansion line, at any distance apart we choose. In this 
 case we drop 3, 4, close together; then 5, 6, 7, at a distance double that 
 between 3 and 4. There is no special reason for making any difference in 
 this. We sometimes drop the ordinates closer together in the first part of 
 the expansion curve, where the greatest variation takes place in expansion, 
 but they can be put as near together or as far apart as the demonstrator may 
 choose. 
 
 Now, from the intersection of the ordinates, 3, 4, 5, 6, 7, and the line B, 
 draw the radial lines from the point K to each separate point of intersection. 
 Now, wherever the radial lines cross the line G, is the point of our next 
 computation. From the points of the radial lines crossing the ordinate G, we 
 next draw lines at right angles to G until they cross the ordinates 3, 4, 5, 6, 7. 
 We have here then following out this process with each one of the lines to 
 their crossing with G, the lines, 8, 9, 10, 11, 12, 13. Now wherever these 
 two lines 8-3, 9-4, 10-5, 11-6, 12-7 intersect, through the points described by 
 their intersection lies the hyperbolic curve from the demonstration. 
 
 In this case it will be noted, to return to the diagram for a moment, that 
 we start off with an initial pressure of 70 pounds. The steam pressure is 
 gradually reduced or, as engineers term it, wire-drawn, throttled so that it is 
 constantly reduced in pressure on the diagram. At the point where the 
 ordinate G is erected, we have 13 pounds less than we started with, or 57 
 pounds realized at that point ; dropping off still further, so that at the point 
 where D intersects the hyperbolic curve we have only 49 pounds. Now with 
 the ordinary demonstration which has been so frequently printed, and upon 
 which so many arguments have been based, in this diagram we should have 
 no possible data with any sort of certainty, for ascertaining precisely where 
 the steam was cut off. In this case, the result proved the correctness of the 
 assumption, and the assumption is based on the fact that the demonstration is 
 correct. The theoretical curve in this case starts from the point B, G, and strikes 
 the actual line of the instrument at the point I, or directly over the line D, and 
 the two lines, which are very clearly drawn (the actual line of the indicator in 
 long dots and the theoretical curve very fine dots), pass over each other for 
 such a proportion of the distance" that the two lines are inseparable until 
 
TWENTY YEARS WITH THE INDICATOR. 145 
 
 almost the commencement of exhaust. At the last ordinate the line of the 
 instrument is very slightly above the theoretical line. The line D may be 
 placed anywhere on the expansion line between the visible point of cut-off 
 and the visible point of release ; . and in the case of some diagrams, which will 
 be shown further on, it will be seen that where difficulty exists, in every one 
 of these points the demonstration proves what the action would have been if 
 there is any accuracy at all to the action of the valves, and a cut off was 
 intended. In this case the action of the engine was fettered somewhat by a 
 late release, we might say, but, as a matter of fact, while the exhaust valve 
 could have been opened a trifle earlier, the amount of steam in the cylinder 
 was enormous, and the exhaust is partially clogged for that reason. It will 
 be interesting when we state that the theoretical use of steam on this dia- 
 
 FIG. 98. 
 
 gram, Fig. 98, measuring the full boiler pressure up to the point of cut-off, 
 then following the theoretical line, making a perfect exhaust, is 792, while the 
 actual useful effect measured by the planimeter is 715, giving us a percentage 
 of a trifle over 90 per cent., and yet this is by no means good practice ; it 
 speaks well for the design of the engine, but not for the management of its 
 owner. 
 
 Kef erring to the demonstration of the point of cut-off, Fig, 98, as com- 
 pared with Figs. 96, 97, shows almost the other extreme of the efficiency of 
 the application of this demonstration to the every-day work of the working 
 engineer. Any engineer with a steady hand can do all that we have been 
 describing. A pair of steel triangles, we prefer, made by Brown & Sharpe, 
 although rubber or wood will do, if they are taken care of, a sharp pencil, 
 and for laying out the theoretical curve a series of curves of different radius, 
 
46 TWENTY YEARS WITH THE INDICATOR. 
 
 which can be bought at any draughtsmen's supply place, and only two or 
 three will be required for a very large range of work this is all the appa- 
 ratus and a board a foot square, covered with blotting paper or coarse rope 
 paper not sized or glazy finished, completes the whole apparatus. 
 
 LESSON XLHI. 
 
 THE DEMONSTRATION OF THE POINT OF CUT-OFF AND THE LAYING OUT 
 OF THE THEORETICAL CURVE WITHOUT REFERENCE LETTERS. 
 
 If the two previous lessons have been carefully studied, the reader will 
 have a pretty good idea of how to do, and what is being attempted. Fig. 99 
 is taken from the steamer City of Worcester, Norwich Line of New York and 
 New England Steamers, between Boston and New York. The diagram illus- 
 
 " ,' I 
 
 ** s r 
 
 M " I 
 
 I... 
 
 / 
 
 /"'' 
 
 .i---X-'--^... 
 
 FIG. 99. 
 
 trated was taken while her engines were being adjusted and before they were 
 fairly complete. We have chosen this diagram for the especial purpose of 
 making the demonstration upon it, not having taken the most perfect one for 
 that purpose. This diagram was taken while she was at full speed, her 
 cylinders being 90 inches in diameter, 12 feet stroke, 35 pounds pressure by 
 gauge, 22 inches of vacuum per gauge, throttle wide open, running 18 4- rev- 
 olutions per minute, 24 scale. 
 
TWENTY YEARS WITH THE IN DIG A TOR. 147 
 
 The bottom diagram in this case carries steam the greatest distance, as is 
 usual in marine engines. We have been compelled to draw our line repre- 
 senting the initial pressure a very trifle above the actual, in order to allow the 
 lines of the diagram to show, for the bottom end of the cylinder, although it 
 takes steam late on the opening of the valve. In this case it realizes full boiler 
 pressure after having traveled several inches, and at the point of cut-off by 
 demonstration loses only three pounds from the initial ; while the top end 
 realizes full boiler pressure to the very point of cut-off visibly. The release 
 as shown in these diagrams is rather late, later diagrams improved it very 
 much ; so the vacuum in this case was improved after. 
 
 The base line in this case is erected at about half-way on the expansion 
 line. The parallels are drawn and the point of cut-off located very closely to 
 what we would have termed the visible point. Radial lines and ordinates are 
 erected as before stated, and where the ordinate and the line from the point 
 of cut-off cross, it will be found to almost touch in each of the four cases, the 
 line of the indicator as it left the diagram, so nearly at least, that we have 
 not thought it worth while to attempt to draw in the theoretical line, from 
 the fact that the two lines are so very close together that it would lead to 
 a confusion in the mind of the reader. The top end of the cylinder is a little 
 late in taking steam but not as late as the bottom ; the result of this is shown 
 in the slightly increased pressure and in the fact that the steam line in itself 
 is much straighter than in the other end. 
 
 We desire it understood that this diagram was not selected to show the 
 performance of the steamer ; it was selected rather as a diagram, somewhat 
 distorted, for the sole purpose of showing that the demonstration of the 
 point of cut-off was equally as applicable to a diagram in which the lines were 
 not clearly established, and that the result could be depended upon for prac- 
 tical application aside from any or all theoretical questions. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 LESSON XLIY. 
 
 MODERN STEAMSHIP ENGINES EXAMINED BOTH WITH REFERENCE TO 
 
 ECONOMY AND THE APPLICATION OF THE DETERMINATION OF 
 
 THE POINT OF CUT-OFF, AS WELL AS A COMPARISON OF THE 
 
 ACCURACY OF TWO DIFFERENT INDICATORS ON THE SAME 
 
 SHIP. 
 
 Figs. 100 and 101 are from a modern steamship running between New 
 
 York and . The diagrams 100 and 101 were taken with an 
 
 English instrument furnished by the builders of the vessel. There are several 
 very noticeable features about this diagram 100. The bottom end of the 
 cylinder gives us more than boiler pressure ; this cannot possibly be, the 
 boiler pressure as given at the moment was 78 pounds, scale 32 ; we have 
 fully 80 pounds as per indicator card. The steam lines are very irregular and 
 the expansion line, it will be noticed, is very much higher than it should be 
 about the point of cut-off, showing first, that the steam is throttled in the 
 passage-ways, and next, that the valve closes slowly and continues to admit 
 steam. The stroke of the engine is 54 inches. We have located the point, of 
 cut-off from the usual demonstration and it will be noticed that the curve from 
 the release, following up the expansion line, denotes where the steam to have 
 been cut off, would have given the theoretical line following the expansion 
 the majority of the way. 
 
 The release of the engine appears to be very good, and it is at 38 pounds 
 above the atmospheric line, but there is something very curious about the 
 exhausting of the engine from either end, with reference to the positively 
 straight line A, B, while as a matter of fact such a line as this, where the re- 
 ceiver is used as between the high and low pressure cylinder, cannot be made, 
 if we are to have any faith in modern engineering. It shows, therefore, that 
 there must be something wrong with this indicator, and if we come to analyze 
 it a little further we shall probably find it. By the indicator, the steam valve 
 closes at 29f inches of the stroke on the bottom ; this gives us an indicated 
 horse-power of 1255J. The exhaust valve closes on a receiver pressure of 19 
 pounds at four inches before the end of the stroke, while on the top end the 
 exhaust valve closes at 5^fo inches, the top giving 1129 horse power. 
 
 If we compare this with the low pressure, Fig. 101, the line B represents 
 the pressure of steam in the receiver, while the line A represents the realized 
 pressure on the piston, which is 11 pounds, while the receiver pressure is 19 
 pounds. We have made the demonstration upon the top end showing the 
 cutting off at 26 J inches of the stroke, giving 1293.72 horse-power, while the 
 bottom end gives 1341.93 horse-power. Only about half the receiver pressure 
 
TWENTY YEARS WITH THE INDICATOR. 149 
 
 is realized, that is carried one-half stroke and shows a very fair performance. 
 The vacuum only 18 inches is realized as the extreme, giving 9 pounds. 
 
 For the sake of comparison, Figs. 102 and 103 are given, taken from the 
 Improved Thompson indicator, the American Steam Gauge Company's build, 
 from the same ship, arrangements previously being made ; these followed 100 
 and 101 as soon as the instruments could be changed, the ship running under 
 the same pressure of steam, same number of revolutions, smooth water. 
 Here we have a decided contrast. Fig. 102 shows the high pressure cylinder, 
 and we have here erected three different curves. A, Fig. 102 is the theoretical 
 curve from the arrow-head in the line D, which shows that that cylinder 
 actually used steam sufficient to cut off at 25- I 5 g - inches, giving an effective 
 horse-power of 988.2. B is from the initial pressure 78 pounds, scale 40, and 
 shows what was expected of the engine, while C is the theoretical curve from 
 the terminal pressure showing quite another result. The line B shows what 
 was expected, viz. : to cut off at one-third and to realize boiler pressure. We 
 find, however, the terminal pressure of the diagram is 27 pounds above the 
 atmosphere, while the terminal pressure of the curve from the supposed 
 point was 20 pounds above the atmosphere. The line C shows the engine to 
 have cut off at 21^^- inches of the stroke, if the terminal pressure was right. 
 It will be seen that the diagram upon which the two curves are erected, only 
 realizes 70 pounds of steam, and that at one-third stroke 12 pounds less than 
 that is realized on the piston head. The line A, as drawn from the data given, 
 shows about the actual performance of the engine cutting-off realized press- 
 ure at 25.7 inches, developing 1075.73 horse-power. The dotted line E, if 
 continued, would barely touch the end of each diagram, and shows the rise 
 in pressure in the receiver, between the commencement and middle of the ex- 
 haust, amounting in this case to about 7 or 8 pounds. The minimum 
 amount of pressure in the receiver in this case is 9 pounds, the greatest 
 amount 14 \ to 15^. 
 
 Another point engineers often require has been carefully figured on the 
 right-hand diagram where B and C are shown, the exhaust valve of the high 
 pressure engine closes at 5.2+ inches before the end of the stroke, while on 
 the left hand diagram the exhaust valve closes at 7.8 -I- inches. 
 
 Fig. 103, scale 10, realizes a trifle over ten pounds of the receiver press- 
 ure. In this case, we have applied the demonstration from the average of 
 the expansion line, as nearly as we can judge. The action of the valves, in 
 this case, shows plainly the change in pressure in the receiver from the com- 
 mencement to the middle of the exhaust. The steam line is a very peculiar 
 one, and the demonstration shows that the valve was closed at 21.7 inches of 
 the stroke, giving a horse-power of 1042.4, while the other end gives 1143.48 
 horse-power. There are one or two points with reference to this diagram 
 worthy of notice. On the left-hand diagram the exhaust valve closes at 11.85 -f 
 inches of the stroke, at a lower pressure than the right-hand end, which closes 
 at 10.53 inches of the stroke. The cushion or compression, in this case, 
 plainly shows that the higher pressure and shorter closure produced the 
 
150 TWENTY YEARS WITH THE INDICATOR. 
 
 highest compression. The vacuum shows a trifle over ten pounds at the 
 highest, the lowest being eight. 
 
 Diagrams 100 and 101 show the total amount of power required to drive 
 the ship as 2510.09 horse-power, while 102 and 103, taken within a very few 
 moments of the others and as near as possible under the same circumstances, 
 show the probably correct action of the valves, and the correct amount of 
 power as 2124.94 horse-power. 102 shows plainly the rise in the receiver or 
 exhaust line, and 103 plainly shows this action in the steam and expansion 
 line of the right-hand diagram. Experiments are now being conducted on 
 that ship with a view to adjustment and finding where the engines will do the 
 best work. We would not attribute any motive, but it is somewhat curious 
 that the indicator furnished should make a difference of a few hundred horse- 
 power in the power required to drive a ship, and, therefore, presumably make 
 the amount of fuel per horse-power less than if the actual amount of power 
 was known to be much less than it was supposed, and the amount of fuel 
 much more than it had been considered. These diagrams are well worthy of 
 a careful study for they will interest stationary engineers as much as marine. 
 We should have grave doubts as to the economy of these engines as compared 
 with some of the examples from other engines which will follow. 
 
 FIG. 100. 
 
TWENTY YEARS WITH THE INDICATOR. 151 
 
 B 
 
 FIG. 101. 
 
 r- 
 
 B 
 
 FIG. 102. 
 
152 TWENTY YEARS WITH THE INDICATOR. 
 
 FIG. 103. 
 
 LESSON XLY. 
 
 3ADLY THROTTLED ENGINE, LOSS IN INITIAL PRESSURE, ANI) LOSS IN 
 
 VALVES. 
 
 The diagram Fig. 104 is from an engine sixteen inches cylinder, thirty- 
 six inches stroke, running sixty revolutions, boiler pressure eighty pounds, 
 
 FIG. 104 
 
TWENTY YEARS WITH THE INDICATOR. 153 
 
 scale forty, with a three-inch feed pipe and a five-inch exhaust pipe. There 
 are points of interest about this diagram well worth examination. 
 
 A represents the line of absolute vacuum, B the line of realized pressure, 
 C boiler pressure. It will be noted there is a wide difference between the 
 lines B C ; for with eighty pounds boiler pressure, there is only 62 pounds 
 initial pressure, the steam valve opens slowly, and we doubt if it ever gets 
 wide open, judging from the steam line. From the diagram there is nothing 
 positive to tell where the point of cut-off is, so we must resort to the demon- 
 stration to gain information. In this case we erect the line, D, rather past the 
 center of the expansion line. We then draw the first parallel, F, from the in- 
 tersection of D A to the intersection of F B. The line E is then drawn 
 parallel with F from A to B. Wherever the line E touches B, from that point 
 drop an ordinate G, which represents virtually the volume of steam admitted 
 to the cylinder to do the work, and this line measures the amount of steam, 
 from the commencement of the stroke to its cutting off, that was used to pro- 
 duce the known pressure at D, supposing the steam had been properly 
 put into the cylinder and that valves and piston were tight so that it was 
 correctly handled after it was once put there ; but, unfortunately, the steam 
 did not get in on the piston as it should have done. Now, had the proper 
 amount of steam been correctly applied between the introduction and the line 
 G, it would have followed out the line B to the point B G, and then would 
 have followed the theoretical line or the dotted line. But in the first place 
 we see that it falls away short of the theoretical line until it reaches the fourth 
 ordinate ; at that point it seems to go above the theoretical line, we find at 
 the ninth ordinate it commences to exhaust at the very point where it should 
 have expanded to. 
 
 To refer again to the demonstration and its purpose, this application is 
 not at all to raise questions to confuse the engineers, but rather to show them 
 different points which arise in our own practice and that of others, where so 
 many of these things are constantly coming up which vex the operator and 
 the builder. In this case it is perfectly fair to presume that the stream drifted 
 in after the valves commenced to shut, gradually ran down on the line G, until 
 the expansion is five pounds at the first ordinate below the theoretical line. 
 This theoretical line is based on the actual pressure of steam at the line D, 
 or the base line, so that the pressure at the first ordinate should have been 
 five pounds more than it is ; at the second ordinate plus three pounds more 
 than it is ; at the third ordinate two pounds ; at the fourth ordinate the lines 
 virtually run together ; at the fifth ordinate the theoretical line runs below 
 the line of the instrument ; at the sixth ordinate still more below ; seventh, 
 eighth, and ninth increase until we stop at the ninth ordinate five pounds 
 above the line, as we were five pounds below at the first, while the distance 
 from the base line D to the ninth ordinate is about the same as that of the 
 ordinate G. 
 
 Now, what is the cause of this almost exact balancing of the figure *? Why 
 has it been below in one point and above in the other ? There are two reasons 
 that could make it so, and the indicator cannot tell us which of the two it was. 
 
154 TWENTY YEARS WITH THE INDICATOR. 
 
 In the first place the pressure actually was below what it should have been , 
 in the last, it was above. Now, this pressure may have been caused by a 
 leaking-by of the piston or valves, and in the one case it would account for 
 the terminal pressure at the ninth ordinate, probably to be more like a leak 
 in the valves ; or, if the steam was wet, there might be a certain amount of 
 re-evaporation which would tend to keep the pressure a little above its theo- 
 retical value or its real value. This shows how unfair it is to base any absolute 
 demonstration on the terminal pressure, as showing the real action of the 
 engine. If the piston had been leaking-by during expansion to any such ex- 
 tent, the leak would have shown on the exhaust of the other side, and as it 
 did not, we know that the opening of the valve was insufficient from the drop- 
 ping of pressure below B on G at point of cut-off, and also that the pressure 
 at B, cut-off at G, gives us the volume of steam to give the pressure, D, at 
 that particular point in the expansion line, and that the valve was slow in 
 closing, or, when closed allowed steam to pass through, or, leaked sufficient 
 steam to raise the terminal pressure as shown, wasting the 62 Ibs. of steam 
 realized in the cylinder by valves insufficient in area and probably insufficient 
 in their relative motion to give steam for the speed of the piston at the reg- 
 ular speed of the engine. 
 
 LESSON XLVI. 
 
 HIGH-SPEED ENGINE DIAGRAM. 
 
 The diagram Fig. 105, in this lesson was taken from an Armington & 
 Sims engine, 8 J inches diameter, ten inches stroke, running at 320 revolutions 
 per minute, boiler pressure seventy, Thompson improved indicator, forty 
 scale. The load in this case was given by a lever bearing upon the under 
 side of the balance wheel, and in several instances the load varied by intention 
 from the mere friction of the engine to 25 or 28 horse-power, within a quarter 
 of a minute. At the particular instant when this diagram was taken, the 
 load was constant for the sake of ascertaining the accuracy of the indicator, 
 and this was only one of several diagrams in the series, and this particular 
 diagram is chosen in order to show the largest range of variation recorded ; 
 in other words, the worst diagram of the set. 
 
 The admission line at A will be seen to vary a little from the vertical line, 
 whereas at B the impact given by the admission raises the pressure some- 
 what, and at the same time is a trifle late as compared with the movement of 
 the piston. The oscillations, it will be seen, are confined, and the steam line, 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 '55 
 
 when fully drawn, stands at sixty pounds, maintaining fifty-seven to the point 
 of cut-off at C. It is a curious fact that some makers of indicators are re- 
 cently claiming that the expansion line musj; be without oscillations, similar 
 to those shown in this diagram, in other words, their instruments draw in the 
 hyperbolic curve perfectly. In this case we wish to call the attention of our 
 readers to the fact that a number of elements are at work between the points 
 C and D, in order to prepare them to reason out in their own minds as to 
 whether our own ideas upon the subject will bear the application of reasoning 
 from the stand-point of fact. 
 
 This engine is traveling very fast ; at the point C the valve is closed or 
 very nearly so ; every thousandth of an inch that the piston moves forward 
 on its stroke increases the volume of the cylinder ; no more steam is being 
 admitted ; an increase of volume means a decrease of pressure ; a decrease of 
 pressure means a decrease of temperature, and a decrease of temperature 
 means, when applied to steam, an increase of water present in the cylinder. 
 Now the ratio of the volume of the cylinder is increasing all the while after 
 
 FIG. 105. 
 
 the valve closes ; the volume increases, the pressure decreases, the water in- 
 creases, etc. Now, is it possible for steam supposing it was a perfectly dry 
 steam at this point, which it is not is it possible to make any instrument 
 that will make any portion of a hyperbolic curve when these several elements 
 are each one working negatively upon the other ? Even after the release 
 commences, which is at D, it will be found then that the variation of volume, 
 temperature, etc., make a still further fluctuation in the line at E, by which 
 time the exhaust port is fully open. We shall show, in a subsequent lesson, 
 that it is not precisely the correct theory, if men are to make truthful in- 
 dicators. 
 
 Now, added to the elements that we have cited, there is another very im- 
 portant one, the expansion and contraction of the metal, the weight of the pis- 
 ton, change in the spring, the friction of the moving parts, which is but ex- 
 tremely little, yet it is something. Perhaps some one can tell us how it is pos- 
 sible to make an indicator tell an untruth, or in other words, make some portion 
 of the hyperbolic curve from C to D, instead of the undulating line, which is 
 
156 TWENTY YEARS WITH THE INDICATOR, 
 
 without doubt caused by the various elements to which we have referred, and 
 it is somewhat curious that when the exhaust valve closes near F, in the com- 
 pression of the steam, the increase of density or pressure by shutting the 
 steam up and compressing it brings back certain units of heat, and that the 
 compression line has certainly, in the same ratio, given us the undulations in 
 .an inverse way, (showing compression) to what the expansion line from C to 
 D is. Compare the lines F A and C D, and tell us why these changes should 
 take place, one proving the other. It will be noticed that the undulations in 
 the line are reversed in F A to what they are in C D, showing that the expan- 
 sion with the indicator piston upon the steam is very correctly noted, while 
 on the other side in compression the steam is driven up against the piston, 
 showing the same effect precisely, but that the directions of the lines are re- 
 versed. 
 
 The diagram shows a very good use of steam ; possibly the action of the 
 steam valve should be quickened a trifle in its relation to the piston of the 
 engine, that would make a somewhat sharper corner at the termination of re- 
 lease and commencement of exhaust, and would also carry the compression a 
 trifle higher and avoid the little hook at A, or in other words, would run the 
 compression line into the steam line and would bring the point B nearer the 
 vertical line shown. Taken all in all, it is a beautiful specimen of the high- 
 speed engine diagram as well as of the indicator's work. The three lines, as 
 shown in the original, are carefully reproduced in all their variation, and the 
 subject of the maintenance of pressure, quick expansion, almost locomotive 
 release, as well as locomotive compression are well executed and illustrated, 
 but with the full effect of boiler pressure to the point of cut-off, or a close ap- 
 proximation to it, and a fine exhaust, both showing that boiler pressure and 
 free exhaust can be realized in this type of engine, and are accomplished in 
 every-day work. 
 
 LESSON XLYII. 
 
 MEDIUM HIGH SPEED ENGINE. 
 
 Fig. 106 is from a different type of engine , one of medium high speed, 
 which has not been running many months. The diagram is from the Buck- 
 eye engine, twenty-four inches diameter, thirty-six inches stroke, 100 revolu- 
 tions per minute, condensing, one of a pair, front end of the left hand. 
 Boiler pressure seventy-two, scale thirty, Thompson improved indicator. 
 
 Some pains have been taken to make the demonstration as plain as pos- 
 
TWENTY YEARS WITH THE INDICA TOE. 
 
 T 57 
 
 sible in this case, for those not familiar with the new method of laying out the 
 point of cut-off, and then applying the theoretical curve for efficiency, or to 
 detect leakages or other troubles. 
 
 FIG. 106. 
 
 On this diagram, 1 represents the absolute vacuum, 2 the atmospheric 
 line of the instrument, 3 the line of realized pressure in the cylinder, which 
 is sixty-eight pounds plus, or a little less than four pounds below that of 
 boiler pressure at the instant of taking. B is our base line from which the 
 whole demonstration is made with reference to the point of cut-off; B is drawn 
 from a point a little to the left of the center of the line of expansion, from 
 that to the line of absolute vacuum. From the intersection of the lines B, 1, 
 the line D is drawn to the intersection of 3, F, representing respectively the 
 realized pressure in the cylinder, the line 3, and F, the admission line. In 
 this case we do not know what the clearance is, so we have assumed nothing, 
 but that the indicator made exactly the lines showing the work done, so that 
 no clearance is included. We show the steam used, and as we do not know 
 what the clearance is, we prefer to call it an unknown quantity. 
 
 C is drawn parallel to D exactly, starting from 1 and crossing the end of 
 B at its intersection of the expansion line. Wherever this line C strikes on 
 3, that is the mechanical point of cut-off, assuming only that geometry is cor- 
 rect in its application, wherever the intersection of C, 3, comes, there is the 
 point of cut-off, which in this case is perceptibly a trifle longer by the instru- 
 ment than by the demonstration ; we do not believe in the system of ordinates 
 or logarithms where pressure and temperature are combined, but we believe 
 if a mechanical demonstration is capable in any one direction, that a mechani- 
 cal demonstration is far better for us to locate our point of cut-off, and not 
 
158 TWENTY YEARS WITH THE INDICATOR. 
 
 be guessing, supposing, assuming, etc., etc.; hence we make the whole of our 
 demonstration mechanical rather than by assumption. 
 
 We have, therefore, the intersection G, our first ordinate with the line 3, 
 is the actual point of cut-off from that part of the expansion line where we 
 have located the line B, from the point A all these lines radiate. (See Lesson 
 XLII in both demonstrations.) 
 
 We locate the point of cut-off mechanically, and then demonstrate the 
 theoretical curve mechanically, so that we notice here a variation of far less 
 than the width of the line, it shows us clearly that the valves of this engine 
 must have been working very nearly tight. Practically they are tight, and 
 wherever any broad variation from the actual line of the theoretical curve 
 from the point of cut-off with this demonstration occurs, you may commence 
 at once to look for leaky valves, piston rings or something of that sort, in 
 this case it means nothing ; we are without the clearance line, and this dia- 
 gram, as it stands, is simply and purely an actual exponent of the work being 
 done at the time, but it does not show the whole bulk of the steam used, only 
 ae we know precisely what the clearance of that end of the engine was, but 
 for all practical purposes we would not give a farthing to know, and it may 
 be well to say here that the clearance, if known, would add its volume to 
 steam used, but would in no way affect the cut off, or expansion. We have a 
 diagram here which shows a very fine working of steam, so far as taking, car- 
 rying, cut-off, expansion and release go. The vacuum might, perhaps, be im- 
 proved in amount, but as it is an independent condenser and no part of the 
 engine, we do not criticise it. It starts with only four pounds, runs down to 
 nine, ten, eleven, then commences to go the other way, making a fine com- 
 pression, though possibly a trifling steam lead. 
 
 One point must be taken care of in locating this basis for the demonstra- 
 tion, and that is, that the ordinate B should never be drawn too early in the 
 expansion line, for steam, like any other body where work is being done, as 
 a steamship or a train of cars, takes a little time for the engine to get to pull- 
 ing, and so it takes a little time for the steam to settle down to its expansive 
 work, and that place which is fair for it, all things considered, is a trifle 
 beyond the center or when the speed of the piston is very slightly diminished 
 by getting up on the crank ; in other words, where the speed of the piston is 
 very slightly slower and the pressure of steam has very considerably dimin- 
 ished ; sometimes sudden fluctuations will be found in expansion line by 
 rings leaky, in such a case get two or three points and demonstrate from 
 each, and so find where the leakage occurs 
 
TWENTY YE ARK WITH THE INDICATOR. 
 
 T 59 
 
 LESSON XLVIII. 
 
 EXPENSIVE USE OF STEAM. COMPARISON BETWEEN EXHIBITED FACT 
 
 AND POSSIBILITY. 
 
 FIG. 107. 
 
 In Fig. 107 we have something not only to think of, but something 
 which we can compare as between the application of geometry to fact and 
 mathematical rendering of the geometrical delineation, by so simple a process 
 that every reader who has a planimeter can, in fifteen minutes, tell whether 
 our statements are correct or not. We have chosen about as awkward a dia- 
 gram as we could conveniently, for two reasons : almost anybody who has 
 been reading our indicator articles for the past few years, can make a demon- 
 stration on a finely-outlined indicator card ; and we have chosen this curiosity 
 more for the sake of the application of our own method of finding out, first, 
 where the steam was cut off, and then finding out what ought to have been 
 done. A represents the line of boiler pressure, which is far above the real- 
 ized pressure in the cylinder ; B represents the atmospheric line of the instru- 
 ment ; C represents absolute vacuum from which all computations are made 
 both for geometrical demonstration of the point of cut-off, and quite another 
 demonstration having nothing to do with the first, which gives us the theo- 
 retical curve, supposing steam does expand either according to Mariotte's 
 law or Kankine's formulas ; but the two demonstrations are not in any way 
 connected, beyond that the line D shows the amount of steam used in the cyl- 
 inder, the volume from C to D being filled, if cut off and properly expanded, 
 and the intersection of line D with the line F shows point of cut-off on the 
 
160 TWENTY YEARS WITH THE INDICATOR. 
 
 line F. The engine from which this was taken was running eighty-two revo- 
 lutions per minute, scale thirty, governed by one of the throttle governors 
 and was supposed to be doing good work. The card made by the indicator 
 starts off with forty-five pounds initial pressure, makes a nice little jog at 1, 
 runs along at forty-five pounds, and commences a peculiar gyration at 2, 
 dropping off suddenly from this point to 3, rising again to 4, and making a 
 peculiar short curve, commencing at 5 again to run in a straight line, and at 
 6 another peculiar vibration. The terminal pressure at 7 is forty-one pounds. 
 We have thus a very peculiar expansion line, and almost any one with any 
 knowledge of steam enginery would pronounce it not by any means a model 
 card, but we have less to do with this than with the next factor in this most 
 interesting case. A little beyond 7 the exhaust valve commences to open 
 and opens slowly, so that at 8 we have twenty-four pounds back pressure, at 
 9 we have seventeen pounds and at 10 ten pounds. The back pressure 
 gradually becomes less until the exhaust valve closes at 11, where it lias 
 been reduced to five pounds ; we have all the space bounded between the 
 exhaust line of the instrument and the atmospheric line of the instrument B, 
 making a large area, the exhaust being, perhaps, a little less ragged than the 
 upper line 1 to 7. The closing of the exhaust valve at 11 is very nearly cor- 
 rect, but the opening from and after 7 shows distinctly that the motion of 
 the valve is incorrect, for it is entirely too slow, if large enough, in its pro- 
 portion to the stroke, and all the area when open is not sufficient ; hence we 
 do not realize the theoretical line of exhaust, nor indeed the usual exhaust of 
 a half pound of back pressure. The planimeter reading of the indicator card 
 precisely as it comes from the instrument is 473 ; the planimeter reading of 
 the area covered in by the back pressure is 144 ; then we have an area of 
 473 + 144=617. Now there are parties in the world who claim (we will call 
 this horse-power) that in this case the 473 horse-power is transmitted to the 
 machinery, and that the 144 amounts to nothing. Perhaps this is so. All 
 engineers know that the boiler capacity is invariably measured from the 
 atmospheric line, and in this case the boiler would receive credit for and 
 would actually be doing 617 horse-power. It is claimed also that the back 
 pressure upon one end equalizes the back pressure on the other ; perhaps 
 this is so ; possibly not. Now, while the piston moves from 1 to 7, the steam 
 is escaping from the other side of the piston, and from 7 to 11 is going on, on 
 the other side of the piston. Now, if we have 473 on one side of the piston, 
 144 added to it, if it were working as it should, but, in this case, working 
 against it, does it require anything on the other side of the piston to push 
 that 144 out of one side of the piston and out of one end of the cylinder, 
 while the steam is making the card upon the side of the piston in the direction 
 of from 1 to 7 ? Now, if this statement is a fallacy will somebody show us 
 where ? In other words we have drawn the line E from the expansion line or 
 steam line, whatever it may be, to the line C ; from the base of E we have 
 drawn a line to the intersection of F G, namely, realized pressure, and the 
 boundary line of the card, giving the steam and vacuum lines, parallels to this 
 line, which is omitted in the engraving. We have drawn from a point on O to 
 
TWENTY YEARS WITH THE INDICATOR. i6z 
 
 the line F, which crosses the line F at the intersection of D F; from this point 
 we drop the line D. Now, the space bounded by the line C G F D represents 
 the volume of the cylinder at which steam should have been cut off in order 
 to produce its equivalent at E. Then by the same plan given in Lesson XLII, 
 we draw in a theoretical line F. Now, we assume here simply that had the 
 engine been handled as an engine should have been, it had a pound or so 
 above the actual initial pressure, that it would have been cut off at D on the 
 line F, and then if the valves were tight it would have expanded according to 
 the curve F, and if it had exhausted as it should have done, it would have re- 
 turned upon the line B. There is something curious about all this. The 
 dotted steam and expansion line with the correct exhaust gives us precisely 
 the same planimeter reading as in the diagram above 473 without the 144 
 back pressure. This may be the correct way of working engines, we mean 
 the actual diagram, but in our own demonstration we have only shown what 
 the engine should have done, providing the steam were worked correctly and 
 at the real boiler pressure instead of that which was realized. It is a little 
 curious that this result conies out precisely as it does, without any calcula- 
 tion other than that all the simple demonstration and the addition of about 
 one-third of an inch in length for clearance. The comparison shows a most 
 expensive mis-application of steam. 
 
 LESSON XLIX. 
 
 A HIGH SPEED ENGINE, RUN AT A LARGELY INCREASED SPEED TO TRY 
 AN EXPERIMENT WITH THE THOMPSON IMPROVED INDICATOR. 
 
 The author was among the very first of the engineers who had actual ex- 
 perience with the high-speed type of engines, beginning with Mr. Porter's 
 engine in 1869, and has had much to do with and has advocated the high 
 speed for certain purposes, and it would seem, perhaps, better if we were to 
 give some few illustrations which have not been previously given. In Fig. 108 
 we give something which we believe never before done, and in this case was 
 done for an experiment, but we presume will soon be adopted as practice. 
 It is a well known fact that in electric lighting long-stroke engines have in 
 some cases proved to be (even with the best regulation) very undesirable, 
 from the fact that on the incandescent light the strokes of the engine can be 
 counted with the utmost precision, if any one will give careful attention to it. 
 On the other hand, with some high-speed engines the short stroke has been a 
 
162 
 
 TWENTY YEARS WITH THE IWJLU'CATOIt. 
 
 disadvantage, by means of not thoroughly overcoming what was expected in 
 the matter of measurement of time as between the long and stort stroke, and 
 the high-speed engine requires a great increase of accuracy, if such a thing is 
 
 i 
 
 FIG. 108. 
 
 possible, over the slow speed, in proportion as the stroke is shorter, than the 
 slow-speed engine. The same factor of an increase of speed from the com- 
 mencement to the middle of the stroke, and the decrease of speed from the 
 middle to the end of the stroke, is present in the short-stroke engine, but it 
 becomes beautifully less in percentage as the stroke is shortened and made 
 more frequent. Tn other words, the visible effect on a high-speed engine, if 
 run at regular speed, is exceedingly little. Regular speed does not mean a 
 great variation, but a close approximation to a certain line, and any varia- 
 tion from this is very noticeable indeed, and is not only noticeable, but has a 
 very pernicious effect upon the film of the incandescent lamps. 
 
 The author was called upon to make a test with some indicators. He 
 had desired very much to obtain an indicator that would give a reliable card 
 from an engine running 500 revolutions. We had no engine ininning 500, nor 
 could we get access to one, but through the courtesy of the owner of an 
 engine we were allowed access to his engine during the noon hour, with the 
 privilege of miming it into the afternoon if we would agree to stay by and 
 take care of it. The regular speed of the engine was a little above 300 per 
 minute. 
 
 We set the regulator arm-springs down as much as we dared to, adjusted 
 our indicators as nearly as possible, and opened the throttle valve. We had 
 intended to run at about 400, but were simply guessing at the tension of the 
 springs. The speed was simply terrific ; counting was entirely out of order, 
 
TWENTY YEARS WITH THE INDICATOR. 163 
 
 and the engine ran as smoothly as at 320. Finally the gentleman who had 
 invented the 500-revolution-per-minute engine decided that he would experi- 
 ment somewhere in the neighborhood of the speed we were using. A counter 
 was then procured, and we found that our speed ran in fifteen seconds 109, 
 thirty seconds 217, one minute 435, and two minutes gave us 866.872 and 
 870. The steam was then let into one of our new Thompson improved in- 
 dicators. Fig. 108 is one of the diagrams taken from the head end of an 
 Armington & Sims engine, 8Jx 10, 435 revolutions, boiler pressure 90, scale 
 40. A represents the line of boiler pressure 88 or initial pressure, C the ver- 
 tical line at right angles to D, which is the atmospheric line of the instrument, 
 and E the line of absolute vacuum. In this case the line of the diagram above 
 C, where the compression closes and the steam valve opens, shows that the 
 steam valve is slightly in advance ; in other words, that there is a little actual 
 lead. The opening of this valve is instant, and the steam in this particular 
 case shows an impact rising of between thirteen and fourteen pounds, but it 
 as instantly descends to about four pounds below realized pressure. The 
 steam line is then carried off very handsomely, and the visible point of cut-off 
 is, we think, for such a speed, very plainly shown. 
 
 Here comes up the old question of what makes a wavy line of expansion, 
 and we do not think we have far to seek in this for the reason. In this dia- 
 gram there is no assumption, for we have all the facts, and the expansion line, 
 as is shown in the first dropping after the cut-off valve has closed, descends 
 something below the theoretical, then rises slightly above, again falls slightly 
 below, and just before the exhaust valve opens at J, the theoretic and the 
 practical line in its oscillations cross each other absolutely. The sudden out- 
 let from J to K shows us that the steam will expand in any thing but a section 
 of a hyperbolic curve, when allowed free egress. At K we have another little 
 oscillation, another sharp curve approximating much nearer to a right angle 
 with the theoretic curve, and at L we have still another oscillation. The cause 
 of this we have frequently been asked for, and lately in a case where the same 
 factor appeared. Our reasoning of this is : From J to K, when the exhaust 
 valve opens, there is a sudden exit of a considerable volume of steam under a 
 pressure of thirty-three pounds above the atmosphere. The exhaust pipe in 
 this case is of quite a length and when the steam from the cylinder, released 
 by the exhaust valve, impinges upon the steam already moving in the exhaust 
 pipe, a little reaction is caused by this very elastic medium, which makes a 
 crook in the line at K. The steam then moves along again, that which is 
 being released from the cylinder striking or pushing the other, all of which 
 is very elastic, and at L the pressure is reduced so materially that no further 
 vibration in the movement of the body of steam can be recorded by the in- 
 dicator ; and this may be further proved, perhaps, by the dropping off of the 
 line as it turns from the termination of the exhaust just below the letter L, 
 dropping down nearly two pounds before the exhaust line starts on its con- 
 tinuation. The line then, it will be noticed, drops a little as the exhaust is 
 completed and before the exhaust valve closes again, a little to the left of D. 
 Here we have precisely these same vibrations or oscillations or changes as the 
 
164 TWENTY YEARS WITH THE INDICATOR. 
 
 compression increases, showing plainly that the exhaust valve closes and the 
 compression ceases in amount of pounds, making a nearly straight line on the 
 upper step before the steam valve opens. 
 
 Proceeding with our usual demonstration, first to find the point of cut- 
 off and the actual amount of steam used, we have erected here the line F, and, 
 if the reader will notice, we have erected it not at the point of lowest pressure, 
 but at about the highest point after the expansion really gets settled. From 
 F we carry the parallels Gr H, and in this case we have included the actual 
 measure of clearance of the engine, embracing the inside of the valve, the 
 passage from the valve into the cylinder and the actual space between the 
 piston and cylinder head, from data obtained from the engine when still 
 and the clearance filled with water. We have therefore drawn G from the 
 intersection of F E to the intersection of A, line of boiler pressure, B repre- 
 senting between C and B the actual amount of clearance as compared with 
 the total cubic contents of the cylinder through which the piston moves. In 
 this case it will be noticed we charge the engine with the absolute boiler 
 pressure ; we also charge it with every particle of clearance at that end of the 
 cylinder. 
 
 Having thus defined the point of cut-off, we draw the first ordinate from A 
 to angle formed by E B, see lesson XLII, starting from the intersection of the 
 lines B E, and we have made the whole demonstration except the point from 
 which the lines radiate, and these are omitted purposely in order to show 
 clearly just what the effect of the action is ; from the joining of the second 
 ordinate with a line at right angles to the first ordinate at the crossing, and 
 the process being repeated by the third, fourth, fifth and sixth ordinates 
 through these points from the first ordinate the theoretical curve is dotted. 
 [t will be noticed that the second ordinate of the theoretical curve crosses a 
 trifle above the actual line of the instrument, and at about the center of the 
 /stroke or when the speed is at its very highest. The third ordinate crossing 
 is a trifle above the line of the instrument, the fourth is a trifle below, the fifth 
 is absolutely on the line. 
 
 At J the exhaust valve opens and the curve is carried forward, passing I, 
 in order to show where it would have come had the pressure been maintained 
 by keeping the exhaust valve closed. We have not figured this for absolute 
 effective percentage, though the percentage is very high, but present it as an 
 example from actual practice, showing that we may charge the engine with its 
 whole clearance, about nine per cent., remembering that the cylinder is 8J 
 inches in diameter, and that while the clearance may be large in proportion, 
 the handling of the steam, charging everything to the engine that we may 
 properly or justly do, is most excellent, even at this tremendous speed. It is 
 impossible at such a speed as this to take a card quite so neatly as we like to 
 do from one running 80 to 125 per minute, for if you touch the paper at all 
 you must necessarily make several records. In his case the lines did not 
 vary the width of one another apart at any point of the diagram, so that we 
 have engraved a single line. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 165 
 
 The question of the recording of the lines of expansion of steam under press- 
 are and the oscillations is, to our own mind, always an evidence of extreme 
 sensitiveness and reliability in the indicator, and we believe that, sooner or 
 later, the real doctrine of the expansion of steam will be settled upon a basis 
 that will not be filled with vagaries. 
 
 LESSON L. 
 
 CARRYING STEAM FULL STROKE AND EXHAUSTING UNDER EXCESSIVE 
 
 BACK PRESSURE. 
 
 In Fig. 109 we have a comparison of high pressure steam, throttled down 
 and then carried full stroke, and, to make the matter all the worse, the exhaust 
 is nearly equal in resistance to the whole amount of work transmitted. We 
 have made some comparisons on this diagram, both from the boiler pressure 
 and the realized pressure, and to show how the effective use of the steam is 
 entirely done away with and no economy attained. Boiler pressure, 100 Ibs. ; 
 revolutions, 114 per minute ; scale, 60. 
 
 FIG. 109. 
 
 The line A in this case is the base of the first combination, B the line of 
 boiler pressure, C the atmospheric line of the instrument, D the absolute 
 vacuum. From the intersection of A D, we draw a line (according to our 
 method of delineation) to the intersection of I B, then on D we lay off 
 
i66 TWENTY YEARS WITH THE INDICATOR. 
 
 towards J the sanie distance that exists between the intersection of A and the 
 steam line of the indicator card and the line D I. From this point on the 
 line D we find the point through the top of the line A which intersects B, 
 from which we drop F, showing the amount of steam used in the cylinder to 
 make the theoretical expansion curve G, showing the amount of steam at 100 
 pounds cut-off to make very nearly the same amount of work as that shown 
 by the indicator diagram and the back pressure ; the planimeter reading of 
 the indicator diagram outline is 219, the back pressure 194, the sum of the 
 two being 413, while if we take 100 pounds of steam, cutting it off so that A 
 shall equal the pressure at that portion of the stroke, we obtain 459. Now 
 there is a point here to be considered ; if we were to make the outline bounded 
 by cutting off the hundred pounds at B F, taking in the theoretical curve G, 
 we have 459 on the planimeter. Now, if we should make the same misuse of 
 steam by the valve in the larger feature, or by cutting steam off in admitting 
 steam, that the indicator card itself makes from K to L, the sum total of our 
 areas should be exact. In the case of cutting off the 100 pounds of steam, we 
 have simply assumed that the cylinder is to be filled at the commencement of 
 the stroke ; so that while with 100 pounds of steam, cut-off B F making G, re- 
 turning on C and admitting again on the line I, we have almost a perfectly 
 theoretical diagram ; but in the actual misuse and abuse of steam bounded 
 by the dotted line, which is the indicator card, we have 219, the back press- 
 ure which should have been useful effect, and the little triangle bounded by 
 the dotted line which is the induction pressure, or realized pressure after the 
 steam valve gets open, the vertical line I and the irregular hypothenuse K L, 
 we have an area of 26 on the planimeter, hence we have 219 4- 194 4- 26 439 
 as against 459 developed by the proper use of steam. 
 
 But there is another factor in the case : Using A in the third computa- 
 tion as our base line, triangulating with the dotted line E, which is the line 
 of realized pressure in the cylinder, we obtain the line H as the volume of 
 steam admitted at that pressure, and the expansion line should follow the 
 lower line M, which strikes the theoretical curve G at N, and then follows so 
 near that it is almost impossible to show the two lines on the card ; this is 
 supposed to exhaust freely, or what the engine should have done had the 
 steam been entered at the pressure E, at the very commencement of the 
 stroke, cut off at H, expanded on M G to the terminal pressure and exhausted 
 freely. In this case we have 352. 
 
 By this time our readers may wish to know what all these letters, figures 
 and lines mean, or where the working engineer is going to learn anything 
 from such a mass of references. Let us see ; in the first place we had a hun- 
 dred pounds of steam, for the scale is 60, the engine was running 114 revo- 
 lutions per minute, it made the dotted line diagram which figures 219 ; sup- 
 pose we call it 219 horse-power, working against the back pressure 194. In 
 other words, the boiler was yielding 413 horse-power to do 219. Steam was 
 carried the whole length of the stroke after it was first admitted. If the 
 steam had been admitted at the pressure represented by the line E, which is 
 about sixty three pounds, and been cut off at H E, expanded as shown by M 
 
TWENTY YEARS WITH THE INDICATOR. 167 
 
 G, it would have produced 352 horse-power with an expense of a little less 
 than half the steam, provided the valve had admitted the steain at the outset 
 and the exhaust had not been checked. On the other hand, had this engine 
 admitted the boiler pressure of one hundred pounds, cutting it off at F on B, 
 properly expanded and exhausted, the steam which was in the boiler and was 
 not used on account of defects in the construction of the engine, a still less 
 quantity of steam would have given 459 horse-power as against 219 horse- 
 power by this wretched misuse of the steam. 
 
 The valves in the engine from which this diagram was taken are very 
 wrong in their construction, and have a fault common to many of the new 
 engines of '83 and '84. They do not travel far or fast enough to give either 
 induction free from the throttling, or eduction free from back pressure ; 
 steam cannot be used profitably or economically without free passage into 
 and out of the engine. 
 
 LESSON LI. 
 
 HARRIS-CORLISS ENGINE -DISTORTION OF DIAGRAM BY THE INDICATOR 
 
 MOTION. 
 
 The approximate value of the correct reading of an indicator diagram is 
 something which can be gained by careful attention to facts, and we believe 
 only in that way. Fig. 110 is a rather peculiar case, from a Corliss engine 
 23 X 48, running sixty-six revolutions, seventy-nine pounds of steam at the 
 moment of taking, nearly eight pounds of back pressure, and was the cause of 
 considerable argument and investigation. 
 
 The line A is absolute vacuum, B atmospheric line of the instrument, C 
 exhaust line of the indicator, D expansion line of the instrument, E realized 
 boiler pressure in the cylinder, F boiler pressure. It will be seen that the 
 engine takes steam very squarely, carries it for a short distance, and immedi- 
 ately commences to drop off. We have located the base line, G, a little beyond 
 the center, in order to allow the steam time for settling down to its work. 
 From the intersection A G we have drawn I E, and parallel to it H ; the 
 intersection of H E by this demonstration gives us the point at which steam 
 was cut off, to give the pressure at G in the stroke. The demonstration is made 
 for ascertaining whether the steam expanded correctly or not from the point 
 E I j and the line J, which is dotted differently than the line D, is the hyper- 
 bolic curve from E I, or the amount of steam used. Curiously enough this line 
 
i68 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 J crosses the expansion line D at the point G, or very near it, and it falls 
 nearly as much below the expansion line of the instrument on finishing the 
 stroke, as it rises above it between H I and G H. 
 
 FIG. 110. 
 
 There is something rather curious about the peculiar formation of this line, 
 as also in the cutting off, and after the question was submitted we wrote the 
 engineer that his engine was either leaking or that his attachment was wrong, 
 which gave motion to the indicator -a, careful draft of all the connections 
 settled the point that the motion was not square with the engine, and that 
 the motion of the paper barrel of the indicator was so arranged that it ran 
 too fast and too slow from distortion of the motion, and showed a "leaky 
 valve " if the motion had been correct but the trouble was remedied by 
 throwing away a bad motion, and using the pantograph properly attached, 
 and the distortion ceased. 
 
 LESSON LH. 
 
 A CURIOSITYIN DIAGRAMS. 
 
 In Fig. Ill we have a rather knotty subject, more for the sake of the infor- 
 mation it contains, but also to show the difference in indicator's performance. 
 The diagram illustrated was taken from a Porter- Allen engine, one of a pair, 
 right-hand engine, back end, boiler pressure eighty-two, fifty scale, revolu- 
 tions 355 per minute, Tabor indicator. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 169 
 
 The admission line A gets on very well until the piston of the engine 
 commences to move, when an oscillation takes place, making a very attenua- 
 ted-looking figure 8. Curiously enough, the first loop seems to be against 
 the motion of the piston and the next one with it, as the steam is introduced, 
 and the movement of the piston so sudden, carries the second slant of the 
 pencil lever up above boiler pressure some twenty pounds ; coming down 
 again as the motion of the piston increases, crossing under B, making a most 
 peculiar curve, dropping into the saw-tooth, and then upward by a reversed 
 curve or a concave, instead of convex movement, turning over again, coming 
 down in the direction of D ; and, if you turn this wrong side up, you have a 
 handsome Roman nose, rather sharp at the point, or a good-looking saw- 
 tooth for a hand saw. The peculiarity of this, again, is a convex instead of a 
 
 FIG. ill. 
 
 concave movement, dropping away considerably from the theoretical expan- 
 sion line, which is dotted in. The vibrations, then, which take place in the 
 expansion line, become less and less, but continue until the very end of ex- 
 pansion and commencement of release. The engine is working with a con- 
 denser, and the line F is that of the vacuum. We have erected, as nearly as 
 possible, the theoretic point of cut-off from our own system of demonstration, 
 charging a moderate amount of clearance ; whether correct or not, we do not 
 know. It will be seen that the demonstration gives us a close approximation 
 to what would ordinarily be termed the visible point of cut-off, or where the 
 expansion line really commences. The second notch comes closely up to the 
 theoretical, the third the same, while the fourth, fifth and sixth are slightly 
 above. Whether this is caused by any possible leak (which must be very 
 trifling), or whether larger clearance would have made it still below, we can- 
 not say, for in this case we have assumed the clearance, and, to our mind, it 
 only shows that there is a certain analogy in the demonstration, and the actual 
 effect wherever an approximation is made, and it also shows that the indicator, 
 at high speed, may possibly become, in a measure, entirely unreliable in its 
 
i7o TWENTY YEARS WITH THE INDICATOR. 
 
 readings of the position of the valves for in a case of this kind there is not 
 the remotest approximation to any position from which we could work to ad- 
 just the valves. The impact of the steam entering the cylinder at the press- 
 ure and speed given, is something fearful and the indicator may not have 
 had a steady motion, and any irregularity, or instability, in the reducing mo- 
 tion would have given the distorted lines shown. The engine from which 
 this was taken does not make any such diagram, and this is introduced as 
 one of the curiosities of practice. 
 
 The question at issue really is : What made these funny-looking crooks 
 and curves in this diagram ? It certainly was not the engine. Was it the 
 motion, or was it some defect in the instrument, or something between the 
 instrument and the cylinder ? Who can tell ? This will be something for 
 the engineers to work over, and it will well repay them for any trouble they 
 may take. There are some curious features about it. This diagram was 
 taken nearly two years ago, but it is just as well worth studying now as ever 
 before, and, without further information, we cannot attribute all the fault to 
 the indicator, or to the engine but an insufficient spring in the indicator, or 
 a tampering with the barrel-spring or a pendulum too weak for the speed 
 and tension, either one will accomplish practically the same result to a 
 certain extent, but not to so radical a change. 
 
 LESSON LIII. 
 
 ADJUSTING CORLISS ENGINE VALVES. 
 
 This time we have an interesting illustration, and we hope our readers 
 will not get confused with the several lines upon it. The diagram (Fig. 112) 
 in this case represents an engine built by one of the best makers, and which 
 had been abused most effectually. A shows the diagram in fine, dotted lines, 
 after the adjustment was complete ,- B, a solid line, shows the second stage, 
 or during valve adjustment ; and C, a wavy line, shows where we found it. 
 This is one of a series of diagrams taken to find out what power parties were 
 using, with a view to ordering a larger engine. Commencing with the dia- 
 gram C, and ninety-five pounds of steam, we obtain sixty-five pounds real- 
 ized on the piston in the cylinder a very bad beginning for a Corliss engine, 
 but the engine was not to blame. Notice the two lines forming an angle at 
 D ; this is about where the line of admission would have come out if it had 
 gone on at the same ratio, with the pressure at that point ; but if the press- 
 
TWENTY YEARS WITH THE INDICATOR. 171 
 
 ure had reached that point, it would have gone forward of D decidedly, 
 owing to the quickening motion of the piston. Now, let us see. The steam 
 valve does not open ; the steam line looks like an 
 old-fashioned poppet valve engine, which began 
 to cut off the moment it was open. It is hard 
 work telling where expansion begins or ends. 
 
 Having looked this matter over, and finding 
 both ends were alike, we moved the eccentric a 
 little more than half an inch ahead on the shaft, 
 so as to quicken the time of movement. B was 
 the result ; the valve opens considerably quicker, 
 and it will be noticed with this change we have 
 eighty-eight pounds of steam. But by this time 
 our crank valve is working nicely, but the head 
 
 FIG. 112. 
 
 valve is pushed back by the jimcrank shaft, or, in other words, the 
 claw pushes the valve back on its seat, so as to get a good hold and start 
 again ; but this wont do, so we must move the eccentric forward again, 
 which is done, and we secure A, which is just about as well as we can do. 
 We have now ninety-five pounds out of ninety-seven ; take steam about at the 
 right spot. Our crank valve at this time is a little too fast, so we must 
 change that on the jimcrank by slowing. 
 
 We have not space here to make all the illustrations that would be 
 necessary, especially as regards the release and compression. It will be seen, 
 however, in the fine dotted line, that the compression and the opening valve 
 merge into one line beautifully. The expansion line looks very nicely, but 
 for the sake of avoiding any confusion we have omitted any demonstration, 
 the object of this being to impress upon our readers the fact that the proper 
 way to open the valve gives the best possible use of steam ; and the reader 
 who may be informing himself with the use of the indicator can see here a 
 most notable case, where the exact opening of the valve gave a prompt cut- 
 off, a beautiful expansion line to all appearances, exhausted slightly under the 
 atmospheric line and compressed so as to make as fine a line as we need to 
 work for. It is a simple lesson, but there is a good deal in it. 
 
 The whole thing was done in less than half an hour, and the engineer 
 and the parties who were looking on, when they came to load the machine, 
 never saw it do so well before. If an engine runs right with a light load, it 
 will run well all the way through, and we have no doubt that this engine 
 would have cleared itself creditably if it had been running and carrying 
 steam as far as it could have done; but under these circumstances there 
 would have been a good deal of loss, for the steam pipes were insufficient to 
 earry any great part of the length of the stroke. 
 
i; 2 TWENTY YEARS WITH THE INDICATOR. 
 
 LESSON LIY. 
 
 EXPENSIVE " CUT-OFF" BY CHEAP ATTACHMENTS. 
 
 The diagram, Fig. 113, was sent us by an engineer with the request that 
 we lay out for him the expansion curve from the apparent point of cut-off, 
 and as nearly as possible from the cut-off made by the quantity of steam really 
 in the cylinder, according to our method previously illustrated, the data of 
 the size of the engine was not given and is immaterial for the purpose for 
 which he asks information. The data which accompanies it is twenty-four 
 spring, fifty-five pounds of steam in the boiler, head end of engine, seventy 
 revolutions. 
 
 The diagram is a peculiar one, in fact a most wasteful one, and for that 
 reason alone it is given space. 
 
 FIG. 113. 
 
 The line A is the basis of our computation of quantity of steam accounted 
 for in the center of the expansion line. [The engine is supposed to be work- 
 ing with a cut-off], B C parallel lines, B extending from the intersection of 
 the vertical line and the line of initial pressure D E, E is the point of cut-off 
 established according to this method of ordinate A, parallels B C, all of which 
 are explained, in Lesson XLH, as the method of locating the exact point of 
 cut-off, taking the expansion of steam somewhere nearest the center or the 
 point of least variation. F is the atmospheric line of the instrument. G the 
 line of absolute vacuum. 
 
 In answer to our inquirers we have taken the visible point of cut-off, D, 
 slightly beyond the sharp corner, and, from the intersection of the line of 
 absolute vacuum and the vertical line or admission line proper, have laid out 
 
TWENTY YEARS WITH THE INDICATOR. 173 
 
 the theoretical curve according to the method referred to above. This line 
 terminates at H and shows a decided change between the visible point of 
 cut-off and the actual terminal lines, the point K in the actual diagram being 
 twenty-seven pounds above the vacuum line and the point H being four 
 pounds above vacuum line, and the point H is where the terminal pressure 
 should be if T> is the point of cut-off as it appears, and if the valves close 
 tightly. 
 
 Taking the line A as the basis of our calculations, we find the point E to 
 be designated as the cut-off by demonstration, a termination of the 
 expansion line proper at I, being 1^ pounds above the atmospheric line of 
 the instrument, 16^ pounds above absolute vacuum, while the real line of the 
 instrument is, as before, iwenty-seven pounds above absolute vacuum. There 
 are some other peculiar features to this diagram ; in the boiler we have fifty- 
 five pounds steam pressure, only thirty-two of which at the outset is realized 
 in the cylinder. If we follow the line of the instrument we find that after 
 the valve commences to close, somewhere near D, there is a gradual sifting in 
 of steam until it passes the intersection of the line A with the expansion line 
 of the instrument ; in other words, the engine takes steam a long way after 
 the cut-off valve appears to be closed, and if there is any economy in the 
 engine, it must be economy in running a cheap engine at an enormous expense 
 for fuel. If the reader will figure the water consumption of this engine, for 
 comparison with any size and speed engine he chooses, he will find it is 
 enormous. 
 
 The exhaust of the engine is anything but good ; starting with nine 
 pounds of back pressure, averaging five, but perhaps this is not all in the 
 engine, our informant does not give us this fact. Whatever may be in the 
 engine it is not a good exhaust. The compression line is fair but the steam 
 admission seems to be late, peculiarly so on the upper part of the line ; the 
 steam-carrying line, or the steam line proper, is very short, and while the 
 visible point of cut-off is sharp to a certain extent, the practiced eye soon 
 discerns that there is no expansion line to the diagram. It shows what is 
 termed sifting in of steam, until considerably past the half stroke. 
 
 In outline the diagram has every appearance to us of a peculiar arrange- 
 ment known as a regulating cut-off, where some sort of a cam is applied to the 
 throttle-valve regulator, which lifts the throttle valve at the commencement 
 of every stroke and drops it again. That probably accounts in the action of 
 the regulator for the peculiar line from between the commencement of the 
 admission line and the steam line. It is a sort of combination which is both 
 unsatisfactory and expensive. The visible point of cut-off, as our writer 
 terms it, at D, equals almost exactly one-ninth of the stroke; while the 
 point of cut-off, supposing the valves were tight, or according to the quantity 
 of steam used in the center of the expansion line, is shown at E, is 16-45 of 
 the stroke or plus one-third ; in other words the engine is actually using more 
 than three times as much steam as is shown by the indicator diagram at a 
 casual glance and without the application of some test to determine it. This 
 is readily shown by the very great height of the termination of the expansion 
 
174 TWENTY YEARS WITH THE INDICATOR. 
 
 line above absolute vacuum. The cutting off of thirty-two pounds of steam, 
 where we should have fifty-five pounds, with a terminal pressure of twelve 
 pounds above the atmospheric line, is eleven pounds too much at the termi- 
 nation of the expansion, and is just about in that ratio to the economical use 
 of steam, as is shown in this case. 
 
 LESSON LY. 
 
 THE CORLI8S OR MODERN COMPOUND HIGH DUTY PUMPING ENGINE. 
 
 Figs. 114 and 115 are from the Corliss Pumping Engine at Pawtucket, 
 R. I. It has been running several years in charge of one of the most intelli- 
 gent and painstaking of engineers, Mr. John H. Walker. 
 
 Fig. 114 is from the high-pressure cylinder, 15 inches in diameter, 30 
 inches stroke, making 47 revolutions per minute, scale 60, steam pressure 132 
 pounds, Corliss upright boilers being used, 130 pounds are realized on the 
 piston and the steam line is carried as straight as is possible to the point of 
 cut-off. The expansion line is a marvel of beauty and correctness ; the release 
 is early and the exhaust into the receiver shows a commencement of ten 
 pounds receiver pressure and a terminal of eight pounds, there is very little 
 rise in the pressure in this case. The admission could hardly be better. The 
 demonstration in this case precludes the possibility of drawing the theoretical 
 line a portion of the way, as the lines would pass one over the other. Very 
 little compression is used ; that, for some reason unknown to us, is one of Mr. 
 Corliss' ideas, to work with little or no compression. There is a very slight 
 difference between the apparent cut-off and the theoretical, but it is so ex- 
 ceedingly slight as to be almost unworthy of notice from a critical stand- 
 point. 
 
 115 is from the low-pressure cylinder of the same engine, the cylinder 
 being 30 inches in diameter, 30 inches stroke, running 47 revolutions per 
 minute, scale 12. 114 is from the front end of the high-pressure cylinder, 
 and 115 from the back end of the low-pressure cylinder. From the ten pounds 
 in the receiver, we have nine pounds initial pressure, gradually falling off to 
 seven pounds before the close of the valve, expanding to seven and one-half 
 pounds below the atmospheric line. The condenser takes hold at twelve and 
 one-half pounds, the maximum vacuum being about thirteen and one-half 
 pounds, or very nearly approximating to the theoretical. The demonstrat 
 
TWENTY YEARS WITH THE INDICATOR. 175 
 
 in this case shows a very close approximation of the actual to the theoretical, 
 taking into account the lowest pressure from the initial and the point of 
 cut-off. 
 
 This engine has been running some eight years, and these diagrams were 
 selected from the regular indication of each day. . Comparing the two dia- 
 grams one with the other, the high-pressure gives about the highest possible 
 effect of steam, and the low-pressure gives almost the maximum efficiency 
 of the receiver pressure for the distance which it is carried. We have, there- 
 fore, a very fine result economically, and through the courtesy of the engineer 
 we are furnished with the following facts from his regular log-book, which 
 has been carefully kept every day since the engine was delivered to the Water 
 Board. This engine was originally built to supply the town of Pawtucket ; 
 since that time they have added a very large mileage of pipe and a large 
 amount of water to the supply, so that the pumping engine is now furnishing 
 double what it was originally intended to do, and this over a very scattered 
 area of territory. The engine is now running, November, 1884, twenty-four 
 hours per day, the actual amount of coal consumed is 216 pounds per hour ; 
 Wilkesbarre egg coal is used, which costs $4.35 per ton of 2,000 pounds, 
 screened ; the amount of ashes is nearly twelve per cent, and when we say 
 216 pounds of coal per hour, this is the actual amount of coal fed into the 
 furnace, no allowance being made for anything. The pumps of this engine 
 are now working under a head of 272 feet. The high-pressure diagram 
 figures 72.658 horse-power, the condensing cylinder figures 65.398 horse- 
 power, making 138.056 ; the variation between the two ends is very trifling. 
 Taking the coal which is actually consumed we have 1.57 pounds per horse- 
 power per hour ; taking the combustible we have 1.39+ pounds per hour, per 
 horse-power. Taking the cost of the power in dollars and cents, calling all 
 coal, we have 3.4 mills per horse-power per hour, while if we figure the com- 
 bustible, we have the cost of one horse-power, per hour as 3.02 mills. 
 
 The duty under the Board of Experts' test, was 133,522,060 foot-pounds 
 for one hundred pounds of coal. Mr. Corliss took exception to this, and de- 
 nominated it the " humbug " test from the fact that allowances were made. 
 An absolute test made afterwards by the same Board on Mr. Corliss' basis 
 gave it a duty of 104,357,654 foot-pounds per hundred pounds of coal, and 
 this duty has been somewhat exceeded in its regular every-day work, while 
 in charge of its efficient chief. The duty' from the time of its start, January 
 31st, 1878, to the 6th of November, 1878, was on fuel consumed to pump, 
 106,234,300 foot-pounds. In June 1882, the engine was stopped for inspec- 
 tion and the piston rod in the low-pressure cylinder, where it passes through 
 the plunger in the pump, was found to be so corroded by the action of water, 
 that it was necessary to have a new piston-rod. This was the first repair 
 made upon the engine. The duty of the engine for the twelve months ending 
 January 1st, 1883, was 113,439,331 pounds of water raised one foot high with 
 a hundred pounds of coal, counting all coal used with no deduction for ash 
 or cinders. 
 
iy6 TWENTY YEARS WITH THE INDICATOR. 
 
 It has been a most gratifying success, both in economy, durability, lack 
 of repair bills ; and the diagrams show if not the highest, certainly a very high, 
 economy considered from any point, taking advantage of no technicalities, 
 allowances or possibilities. These diagrams may be studied critically, in 
 comparison with those in some of the preceding lessons, where compound 
 engines of foreign builders are compared, and with favor to Mr. Corliss, upon 
 grounds of absolute fact, with no assumed allowances of any kind. 
 
 FIG. 114. 
 
 "**-. 
 
 FIG. 115. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 177 
 
 LESSON LVI. 
 
 SHORT CONNECTIONS TO THE ENGINE, WITH NO CHANGE OF POSITION 
 FROM THE THREE-WAY COCK ATTACHMENT IN FIG. 117. 
 
 Diagram Fig. 116 is one which is somewhat peculiar in respect to an ex- 
 cessive cushion. It is taken from one of the new Buckeye engines, running 
 222 revolutions per minute, with a steam pressure at the moment of 92 
 pounds, scale 50, Thompson improved indicator. 
 
 In justice to the engine we will say, the party in charge was partial to the 
 three-way cock for indicating, and Fig. 116 was taken from the same engine, 
 with not the least change of valves from Fig. 117. Let the reader compare 
 the two outlines. 
 
 In this case, A equals the vacuum line, B the atmospheric line, C boiler 
 pressure at the moment of taking, D highest pressure by compression, E 
 point at which the exhaust valve closed on the return stroke. In this case, 
 the exhaust valve closed at about 3|- inches before the end of the travel, and 
 
 FIG. 116. 
 
 although the engine was exhausting very freely, in fact, without any per- 
 ceptible back pressure on the indicator, it will be seen that at the point F, a 
 little more than a quarter inch from the end of the stroke, the compression 
 amounted to 113 pounds. From F, the rest of the stroke, there appears to 
 have been a slight leak, a portion of which was undoubtedly in the indicator, 
 and some of it may have been in the piston or valves of the engine, so that 
 from the point F the pressure falls away to the angle indicated by the dotted 
 
178 TWENTY YEARS WITH THE INDICATOR. 
 
 line G. From this angle it will be noticed that the pressure continues to fall, 
 while the engine had passed the center and the indicator had commenced to 
 move again in the direction of the outward stroke ; G indicates the point at 
 which the crank passed the exact center of the return stroke, and commenced 
 its outward stroke ; meanwhile the steam pressure slightly drops until H is 
 reached, which give us between 87 and 88 pounds initial ; from H to I the steam 
 is carried, and at I the steam valve commences to close. 
 
 The peculiar angle formed by the line dropping from its highest point, F, 
 is caused by a fall of pressure while the engine completes the last portion of 
 the stroke, the angle in the line F, H, shows the precise point where the mo- 
 tion of the engine changes, and after the motion has changed the pressure 
 still continues to fall, showing that the valves of the engine were in a splen- 
 did condition and were tight. At H we have the first real evidence of the 
 steam valves opening, and the steam line crosses the compression line, making 
 the steam line H I. Here we have another most interesting example of the 
 efficiency of the indicator when correctly applied, and its lines correctly read 
 from the diagram. In many cases such a compression line would be at once 
 called an early admission line or " taking steam too quick " but such is not 
 the case. v. 
 
 Now, to analyze the diagram for efficiency, we will commence our demon- 
 strations by the line K, the actual pressure at K gives us an absolute cutting off 
 of the pressure of steam realized at C, J, so that while the valve commences to 
 close at I, apparently it becomes closed at J, or very nearly so ; from J to K 
 the theoretical curve runs slightly above or outside of the actual curve of the 
 instrument ; from K to L, the point of commencement of release, the theo- 
 retical line runs slightly under the actual line of the instrument. The release 
 is most excellent, and it commenced under about twelve pounds pressure, 
 making a very clear exhaust and commencing to compress or cushion too 
 early and making the loop. The particular feature of this loop is a very con- 
 siderable shock to the engine ; in fact, there is quite too much compression, 
 and if the engineer will reduce this compression by one-half, his engine will 
 sail over the center much easier, and without so much wear and tear on the 
 connections, brasses, etc, The boiler pressure in this case is very hand- 
 somely realized, showing that the makers of the engine have made considera- 
 ble improvement in proportion and motion of their valves. 
 
 Taken all in all, the admission and expansion, release and exhaust lines 
 of the diagram are excellent, the compression is no fault of the design or 
 mechanical part of the engine, if the compression is reduced to less than one- 
 half the amount shown here. The engine will do more work with the same 
 steam, and will regulate better without any doubt. It is not policy to com- 
 press twenty pounds above the initial pressure you are working with ; it does 
 not make the valves last any longer, or work any easier ; it causes entirely 
 too much strain on the brasses and connections, and is bad policy every way. 
 The dotted line M, from the line J to the vertical line at the end of the dia- 
 gram, gives the volume of the cylinder filled with steam, simply for the pur- 
 pose of computation. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 179 
 
 This lesson is a most complete demonstration of the lack of reliability of 
 the three-way cock attachment, when used to adjust the valves. Fig. 116 
 was taken, close connection, on each end of the cylinder, only one end shown. 
 
 LESSON LVII. 
 
 THREE-WAY CONNECTIONS FROM SAME ENGINE AS LESSON LVI. 
 
 The old way of side pipe and three-way cock still exists. It is entirely 
 useless for adjustment of valves or for any other than approximation to 
 power, position of valves, or realized pressure. 
 
 The reader will find food for thought in carefully comparing diagrams, 
 Figs. 116 and 117, with each other both were taken from the same engine, 
 with no sort of change except the side pipe and three-way cock were used in 
 Fig. 117 and taken off in 116, the spring of indicator being changed to suit 
 the increased boiler pressure in 116. 
 
 ">.. 
 
 X ,*' 
 
 \/ 
 
 /5S. 
 
 V 
 
 FIG. 117. 
 
 Figure 117 was taken from a Buckeye engine, made by the Buckeye 
 Engine Company of Salem, Ohio, nine inches diameter of cylinder, fourteen 
 inches stroke, 225 revolutions by the counter, eighty-five pounds of steam in 
 the boiler, throttle valve wide open, scale of spring, forty, Thompson im- 
 proved indicator. This engine was on exhibition at the American Institute 
 Fair, New York, and is one of the Buckeye Improved. The makers have for 
 
i8o TWENTY YEARS WITH THE INDICA TOR. 
 
 the past year been making changes, with a view of improving the economy, 
 the regulation and the action of their engine. 
 
 The engine was running electric lights, and this will plainly tell of any 
 trouble in regulation. The diagram 117 was taken upon one of our own in- 
 dicators, but it has just this defect, it was taken by a three-way cock in the 
 center of the cylinder, a thing which we disapprove of, from the fact that it 
 introduces inaccuracies. The steam had entirely too much water in it, but 
 that should not be taken into account against the engine. 
 
 The application of the theoretical curve to the diagram shows a very good 
 action indeed of the valve, and we have taken the highest pressure realized 
 at the moment of impact, and it will be noticed that the theoretical curve 
 follows down past the center of the stroke, almost on the actual line of the 
 instrument. Below the center or half-stroke, as the motion is changed from 
 fast to slow, the actual line of the instrument rises somewhat above the theo- 
 retical. This may be caused by the change in the pressure and the amount 
 of water present ; it probably is not any fault of the valves. The action of 
 the valves on this engine is certainly very good. It is one of the best 
 Buckeye engine diagrams we ever saw, and if the improvements are up to this 
 quality of work, the engine will do better work than ever before, and give the 
 best results. 
 
 We have only made the theoretical curve upon one of the cards. There 
 are several points in it to study, particularly the action of the steam valve in 
 taking steam, the difference in compression as between the two ends. This 
 short diagram was made use of because we refused to take a diagram from 
 another instrument of greater length, which does not show the oscillations in 
 the expansion line, and makes quite a difference as between the compression 
 shown by the Thompson. We would call especial attention to the serrations 
 or fluctuations in the expansion line, which show the most delicate action of 
 the indicator and the variations caused by rapid expansion and changes of 
 temperature, pressure, etc. 
 
 These diagrams bear close examination, and are a very close approxima- 
 tion to the theoretical expansion, bearing in mind that tha position of the 
 valves and their action as to motion are erroneously shown by that attachment, 
 which should be prohibited everywhere e, three-way cock am! long side pipe. 
 [See lesson LVI in connection with LVIL] 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 181 
 
 LESSON LYIII. 
 
 HIGH COST LOW ECONOMY STEAM YACHT COMPOUNDS. 
 
 Fig. 118, H. P., 119, L. P., are a pair of diagrams from one of the rich men's 
 fancy yachts, more expensive than fast. 118 is the high-pressure diagram which 
 
 FIG. 118. 
 
 FIG. 119. 
 
 came to us without any atmospheric line ; 119 is the low-pressure diagram ; 
 the scale of the high-pressure being fifty to the inch. We have assumed the 
 dotted line as atmospheric line in Fig. 118, at slightly an excess of the realized 
 pressure on the low-pressure diagram, which is sixteen per inch. We have 
 
t82 TWENTY YEARS WITH THE INDICATOR. 
 
 twenty-six pounds realized pressure on the low-pressure cylinders ; on the 
 high-pressure cylinders we have made no demonstration, from the very fact 
 that we are not certain of our data, and at the best they are as wretched 
 diagrams as were ever taken from anything in the shape of a steam engine. 
 Those who are interested will understand that a link motion is used, but it 
 must be a sorry link which makes such a use of steam as is shown in the steam 
 line of the solid-drawn diagram. In Fig. 118 the admission line commenced 
 very well, but when the steam line begins it is a curious line ; really there is 
 no cut-off to it, the expansion line is a fearful one, and not economical or cor- 
 rect, and is convex instead of concave, and when it comes down toward .he 
 release, the line instead of being an expansion is turned into saw-teeth. Like 
 most compound engines, the exhaust line is considerably higher in the center 
 than at the commencement. This is all natural enough, but when we turn to 
 the dotted line on Fig. 118, we have, if anything, a worse line than the solid 
 line in the diagram ; a peculiar jump about the commencement of release we 
 are unable to account for satisfactorily to ourselves, but which is probably 
 caused by low-pressure cylinder valves. 
 
 If the party who took the diagrams had been careful to draw in his at- 
 mospheric line, we should have been pleased to make a demonstration. We 
 have drawn in the atmospheric line at about what we supposed it should be 
 drawn, and this gives us full initial pressure 105 pounds, as the throttle valve 
 is wide open, and the link full, scale fifty. On the low-pressure card we have 
 something more to work by, for in this case the atmospheric line is properly 
 drawn in by the instrument, scale sixteen, link up full, speed in both cases 
 126, wide open. Here we have an impact initial pressure of twenty-six pounds, 
 a vacuum of about nine pounds. The cut-off is very well defined in the solid 
 line and less so in the dotted. We have made two demonstrations here, one 
 with the dotted line and the other with the solid line. The dotted line is to 
 ascertain whether the steam expands under the generally conceded theoretical 
 law after expansion apparently commences. The solid line shows what ought 
 to have been done at the actual pressure at the point of cut-off which is visible. 
 We start with a pressure of twenty-three pounds ; at a little past half stroke 
 it runs down to 13^, and the diagram line of the indicator shows that the 
 valve closes. The dotted line shows that the valves were practically tight, 
 for the pressure falls away triflingly, if we take the commencement of release, 
 or just prior to that point, as the basis of that computation. But if we take 
 the actual pressure before the valve becomes positively closed on the line, we 
 find that the general ratio of expansion is closely on the theoretical, under- 
 standing always that there will be more variation in the link motion than in 
 the positive eccentric and lever or rock or wiper motion. Now, if we use our 
 sixteen scale as a rule, we find the solid line from which our demonstration is 
 made to be twenty-five inches (call it) from the commencement of the stroke. 
 At this point 13 pounds of steam were cut off, having been reduced in press- 
 ure from twenty-three, and carried, we will say, twenty -five inches. Now if 
 the pressure had been realized it would have required only eighteen inches, 
 cut off at twenty-three pounds, or, in other words, it would have required 
 
TWENTY YEARS WITH THE 1MDICA TOR. 183 
 
 18-25, or two-thirds, practically, the amount of steam it did require. The 
 high-pressure diagram is abominable, and the use of steam is without any 
 sort of economy, the pressure drops rapidly both on high and low-pressure 
 cylinders after the valve gets open. In the low-pressure cylinder there may 
 be some excuse from lack of volume, or pressure varying in receiver, but in 
 the high-pressure cylinder it is choked or wiredrawn by insufficient ports or 
 pipes. 
 
 These engines were built in 1883. It is, perhaps, needless to say that 
 this is not the fastest yacht in the world by any means, and whoever the 
 builder may be, he need not consider himself particularly nattered with this 
 kind of result, if economy is to be considered at all. 
 
 LESSON LIX 
 
 ANOTHER OCEAN S. S. COMPOUND ENGINE. 
 
 We hear so much of the economy of some of the new ocean steam- 
 ships that it will do us much good, perhaps, to examine some of the 
 results of the work of the engines, and for that reason diagrams, Figs. 120 and 
 121, from the high and low-pressure cylinders of a compound engine are 
 introduced ; the high-pressure cylinders of which are seventy-two inches di- 
 ameter, sixty-six inches stroke, fifty-four revolutions, seventy pounds boiler 
 pressure, scale thirty-two. The same letters apply to the same lines on each 
 for comparison. On the high-pressure diagram steam is cut off at about 
 18-49 of the stroke. Starting with a boiler pressure of seventy pounds, E, 
 and do not get within seven pounds of it on the piston. There is very little 
 approach to an expansion line, and no one can tell where the valve closes 
 from the appearance of the line. In fact, there is no marked feature of it to 
 show where any expansion takes place. 
 
 The steamer in question has been built several years, and is not by any 
 means the fastest or the most economical now afloat ; she was built to ac- 
 complish a certain purpose and has done it, but she has never been economical 
 with fuel to the extent that some of the more modern compound engines have 
 been except by remote approach. 
 
 Making a the base of. our computation, give us B, E, point of cut-off and 
 volume, reference letters the same in both diagrams. From B, the pressure 
 given at a, the line F shows us what power should have been exerted and where 
 the steam should, under ordinary conditions, have been cut off and expanded 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 to. It will be seen that the boiler pressure is not realized, cut-off is entirely 
 lacking in denniteness, and the end of the expansion is considerably above that 
 point which the actual pressure at a gives from the cut-off B, E, showing 
 clearly that there is either a very radical error in the indicator motion, which 
 is hardly probable, or if we look at the low-pressure cylinder, or that the 
 
 valve is slow in closing, or 
 that the valve leaks, which is 
 the most probable reason of 
 all, for we are certain that the 
 valve closes slowly from the 
 course of the line. The high- 
 pressure cylinder exhausts 
 under a pressure of about 
 eleven pounds to start, at the 
 center it is fifteen, and at the 
 commencement of compres- 
 sion it is almost fourteen. 
 The admission line is a little 
 late in the opening of the 
 valve, and the rounding over 
 at the corner is not of neces- 
 sity due to the link motion 
 which was used, but rather 
 to some little give or play, 
 or what is usually termed 
 lost motion. We cannot con- 
 sider this as a very econom- 
 ical diagram, there "is too 
 much loss in realizing the 
 boiler pressure, and a wire- 
 drawing of the steam, (if 
 tight valves) and the exhaust 
 of high-pressure cylinder into 
 receiver is fully as high as it 
 should be, and much higher 
 than the low-pressure util- 
 izes. The expansion line is 
 not nearly as good on the 
 high as the low-pressure 
 cylinder. 
 
 Taking the low-pressure card made at the same time, E representing the 
 initial pressure from the high-pressure cylinder or receiver, a the base line, 
 gives us B as the volume of cylinder at which the valve should have closed to 
 have made the pressure at a, and in this case we have a tighter valve and a 
 very much better condition of circumstances, showing but exceedingly trifling 
 variation as between the theoretical and actual, taking the pressure at a from 
 
 120. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 185 
 
 which to make our demonstration. In this case the pressure is a variable 
 quantity, changing from one to the other cylinder in exhausting and the acceler- 
 ation of speed of the piston, as well as in condensation, which may take place 
 in the passage or in the receiver, so that we lose somewhat in the low-press- 
 ure cylinder from what should be the initial pressure if we had received the 
 whole eleven pounds from the exhaust of the high-pressure cylinder, passing 
 through the ports and into the low-pressure cylinder. We, therefore, get 
 only nine pounds realized, and lose again before cutting off about four pounds 
 more, expanding below the atmospheric line ; in this case we have ten 
 pounds vacuum in the condenser to start with, and this is held very well 
 until more than two-thirds of the stroke has been made. 
 
 Here is an answer to those people " who do not believe any cushion can 
 be obtained in the low-pressure cylinder ;" if not, then what makes the com- 
 pression in this diagram ? It commences to compress at about 7-45 of the 
 stroke, say one-sixth. The admission line is very square, and the admission 
 
 !\ 
 
 FIG. 121. 
 
 and carrying of steam in the lower-pressure cylinder is better than it is into 
 the high-pressure. The expansion line and the theoretical line very nearly 
 coincide through the major part of the distance from pressure at base line a, 
 showing conclusively that the valves in this case do not leak and that the dif- 
 ference in the high-pressure diagram (probably taken by the same motion) 
 cannot be in the motion but is in the valve. A decided falling off from 
 pressure that under the circumstances should hardly be allowable, and about 
 two-thirds the vacuum that should be realized is obtained. 
 
 We do not know the precise percentage of coal this steamer is now 
 burning, but it was very largely in excess of some of the later steamers at the 
 last time we knew of it. The lower-pressure cylinder is 120 inches in 
 diameter, sixty-six inches stroke, fifty-four revolutions per minute, scale 
 twelve, pressure variable. It may interest some of our readers to figure the 
 power in these diagrams from the data given. The low-pressure cylinder 
 
1 86 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 cuts off at about 17-45 of the stroke, starting with an initial pressure of nine 
 pounds, cutting off at a pressure of a trifle over 4J pounds ; the commence- 
 ment of release is four pounds under the atmospheric line, which shows a 
 very good grade of expansion. But we must not expect perfection in these 
 large engines, although we might probably attain higher results of duty than 
 these particular diagrams show. The principles of adoption are the same 
 economy, speed, etc., as with the stationary engines. There is plenty of data 
 here to figure from, and it would be interesting, for those who care to take 
 the trouble, to solve the points of ratio of expansion, the amount of water 
 power, etc. 
 
 LESSON LX. 
 
 AN EXPERIMENT BY AN ENGINE BUILDER. 
 
 FIG. 122. 
 
 Fig. 122 is from the first engine of a new builder for the especial purpose 
 of electric lighting. The data is: Boiler pressure 70, spring 40, diameter 
 10, stroke 12 inches, revolutions 115. 
 
 To attempt to demonstrate all the faults in this engine would be to do 
 work which should have been done by its designer and builder ; for this we 
 have neither the space nor the disposition. This is evidently a very bad imi- 
 tation of a well-known engine. Taking initial pressure, seventy pounds 
 boiler pressure ; to economize room we have traced the dotted line card, show- 
 ing the same engine under a little different load. We have fifty-six pounds 
 
TWENTY YEARS WITH THE INDICATOR. 187 
 
 initial pressure out of seventy. This in itself will condemn the engine, pro- 
 viding the connections are free. The engine starts off with a round instead 
 of a square corner between the admission line and the steam line. With an 
 initial pressure of fifty-one pounds, gradually rising to almost fifty-five, and at 
 about the point where the cut-off appears to take place, we find between forty- 
 five and forty-six pounds of pressure, having fallen off ten pounds in carry- 
 ing steam four-tenths of the stroke. The engine commences to release with 
 a pressure of seventeen pounds on the piston, releases very well, but does not 
 get down in the exhaust to the atmospheric line ; compression starts at rather 
 more than half the distance that the steam is carried. The compression line 
 here may have been shaken up by a poor foundation, but more probably by a 
 constant changing of pressure in the compression in the solid line card, but 
 in the dotted line the compression line is a very queer one, and the little 
 hook at the extreme end, with the peculiar formation of the steam line, in 
 starting on to take steam for the stroke, shows that the valve does not open 
 as wide with a light load as with a heavy one. Notice that the steam is cut 
 off at a very much lower pressure in the light load, proportionately, than the 
 full load, on the larger diagram of the two. Whatever makes the funny jog 
 in the dotted line on the expansion line after cut-off, or whether the steam is 
 carried to that point of the indentation and then the cut-off actually takes 
 place, we are a little at a loss to tell from the appearance, and the card has no 
 value in an economical way. 
 
 The diagram is very uneven, and contains so many faults that we have 
 not cared to give the time to a demonstration on the expansion curve. This 
 engine would be most decidedly lacking in economy ; whatever its regulation 
 may be we do not know, but it was evidently built by some man who has not 
 progressed into the new style of valve motion, for the valves do not travel 
 correctly nor far enough. Whatever their proportions of ports may be we do 
 not know ; one thing is sure, it is too small, either by insufficient opening of 
 the valve by the action of the regulator, or by insufficient ports and passages. 
 Such a diagram may do fairly at 115 revolutions per minute ; what would it 
 do at 250 or 275, the usual speed of the engine of which this motion is 
 evidently a copy I 
 
1 88 
 
 TWENTY YEAK8 WITH THE INDICATOR. 
 
 LESSON LXL 
 
 EFFECT OF SPEED ON REALIZED PRESSURE IN THE CYLINDER A 
 LESSON ON FEED PIPES. 
 
 In Figs. 123, 124, \ve have valuable information in reference to one of the 
 most important, least-attended to details of steam engineering. Both these 
 diagrams are taken from the same engine, under the same conditions, except 
 with reference to speed. Fig. 123 is from the engine in its regular work. 
 Cylinder diameter 34 inches, stroke 60 inches, revolutions 50 per minute, 
 boiler pressure 69, scale 40, condensing. We find 62 pounds of initial press- 
 ure realized. By the demonstration, with A as the base line, we find the cut- 
 off at D, C. The theoretical curve, it will be seen, follows the expansion line 
 exactly, covering it from a short distance beyond the line D, which is quite 
 sufficient for the purpose of demonstration, showing that the 62 pounds steam 
 
 FIG. 123. 
 
 pressure cut-off at D, would make precisely the expansion line, making a most 
 effective working of the steam; and for determination of the one point of 
 particular interest in this lesson, viz., that the feed pipe in this case was 
 amply sufficient to supply that engine at that speed, doing that amount of 
 work. In our own practice we would prefer to have had the exhaust valve 
 open sooner, as at F, in order to allow the condenser to sooner realize the 
 vacuum. In this case, on the opening of the valve, about four pounds is 
 realized, while, were the valve opened slightly earlier, ten pounds ought to 
 have been. If the exhaust valve opened sooner, it would necessarily close 
 sooner, and we should have an approximation of the compression line to that 
 of G. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 189 
 
 In Fig. 124 we have the same engine running 68 revolutions per minute 
 for some especial work required ; at the time of taking the diagram, we have 
 73 pounds of boiler pressure. In this diagram, 124, it will be noticed that 
 the admission line is a trifle late, the initial pressure realized is 72 on the 
 very commencement of the stroke, or before the piston gets into motion; 
 directly the motion of the piston commences to increase, the pressure falls 
 
 away very rapidly, so that at the 
 point of cut-off we have only 58 
 pounds. The demonstration in 
 this case shows that the pressure 
 falls very rapidly indeed, from the 
 commencement of the movement 
 of the piston until at the point 
 where the theoretical curve and 
 the actual line of the indicator 
 touch, just above the letter D; 
 there was 20 pounds less realized 
 pressure than at the commence- 
 ment of the stroke, leaving 52 
 pounds effective pressure on the 
 piston only. 
 
 The demonstration in this 
 case, made from the point A, gives 
 the cut-off on the line C, from 
 which the theoretical curve is 
 dropped, exactly following the 
 line of expansion from the inter- 
 section of tho two lines to the 
 point which is the base of the 
 demonstration. Upon continuing 
 this line, the terminal pressure 
 will be found slightly above, show 
 ing that a volume of steam, equiv- 
 alent to the full pressure, on the 
 line C up to the line between B, D, 
 was used to effect this. In the 
 case of this movement, we find 
 FIG. 134. that the supply pipe for this en- 
 
 gine, which was sufficient for 50 
 
 revolutions, is entirely insufficient for 68 revolutions; and we also find 
 another feature at the terminal of the expansion line, viz., that a very much 
 less vacuum is obtained, and none at all until after the piston has returned 
 several inches on its stroke. The maximum vacuum is ten pounds ; the first 
 quarter of the stroke eight pounds only is realized ; the second quarter nine, 
 the third quarter ten, and the cushion commences on ten pounds. Had 
 the exhaust valve been timed earlier, as recommended for 123, we should 
 
190 TWENTY YJSARS WITH THE INDICATOR. 
 
 have obtained the dotted line E or some approximation to it, and the dotted 
 line F, as a realized vacuum, which would have added materially to the power 
 of the engine and also in the saving of steam. Allowing the alteration to 
 have been made in the time of the exhaust valve, we should also have obtained 
 the compression line G and have compressed to 35 pounds, saving exactly 
 this amount of live steam in opening our steam valve upon 35 pounds instead 
 of nothing. This shows the necessity of a proper supply, and that the supply 
 pipe must be proportioned to the speed at which the engine will travel, and 
 that unless this is done some such change in matters will occur as that shown. 
 Should 123 call for a much larger load, the supply pipe in that case would be 
 insufficient, for it must be understood that after the piston goes a proportion 
 of the stroke in its travel, it calls for steam very much faster than when it first 
 starts. In this case, 123, the pressure is somewhat reduced, and if the engine 
 were required to carry three or four inches further we should probably find, in 
 a less degree, the same features attending the steam line as in 124. 
 
 LESSON LXII. 
 
 ANOTHER LESSON ON SUPPLY PIPES. 
 
 Changing the circumstances as much as possible to make the application 
 more forcible, we have taken Fig. 125 of the high-speed class of engines and 
 running under fully as much load as the builders recommend. This is taken 
 from an Armington & Sims, 14 J inches diameter of cylinder, 13 inches stroke, 
 running 245 revolutions per minute, boiler pressure 92 pounds, scale 60, in- 
 dicating about 125 horse-power, fed with a six-inch steam pipe. The realized 
 pressure is 83 pounds, the steam is carried 150 feet frpm the boilers through 
 several elbows. 
 
 The demonstration in this case by the line A, parallels B B, gives the 
 point of cut-off at B C (for clearness the ordinate is not drawn), C represents 
 the steam line, its cut-off is very sharp. The oscillations in this diagram are 
 referred to in previous lessons, and the point of cut-off and the following of 
 the theoretical curve is through the intersecting points of the lines d d which 
 are drawn at six different places in the expansion line. It will be seen in this 
 case, that the variations in the line of expansion of the instrument vary but 
 very slightly from the actual passage of the theoretical line, and this approxi- 
 mation is so close that the drawing of the theoretical curve would simply con- 
 
TWENTY YEARS WITH THE INDICATOR, 
 
 191 
 
 fuse. The commencement of release at the point E compares well with the 
 compression F, but if anything the compression is slightly larger in propor- 
 tion to the stroke than the release, and in a high speed engine this is some- 
 what a necessity. The exhaust line varies only in the least possible degree 
 from the atmospheric line of the instrument until the exhaust valve closes at 
 F. The compression line has the same wavy appearance that the expansion 
 line has, but exactly reversed in effect. We have a compression here amount- 
 ing to 60 pounds when the steam valve opens and the admission line is 
 formed. 
 
 The amount of power yielded by this engine is large, when we take the 
 volume of the cylinder into consideration, but is not its maximum power when 
 we take its speed into consideration. The admission and steam lines are very 
 square ; the cut-off is very clearly marked and all the lines of the diagram 
 give a high efficiency, which has since been proved by trial of the engine, and 
 in comparison with Figs. 123 and 124, it will be seen that a very large pipe 
 for the volume of the cylinder is required as the speed is increased. The 
 efficiency of Fig. 125 is above 90 per cent, and shows good sense in connec- 
 tions, as the outline, in itself, shows very satisfactory work with the steam so 
 far as valves and engine are concerned. It is probably in three cases out of 
 five that we find too small feed pipe, and in entirely too many cases too small 
 exhaust pipes as well. Both of these points work against the efficiency of the 
 engine and whenever efficiency is involved then economy is certainly less than 
 it should be. The comparison between the three diagrams 123, 124, 125 will 
 be interesting on this point of feed pipes, realized or lack of realized pressure. 
 
 FIG. 125. 
 
I 9 2 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 LESSON LXIH. 
 
 LARGE CYLINDER, LOW-PRESSURE ENGINE ON A SOUND STEAMER. 
 
 Fig. 126 was taken from the steamer Providence, one of the Old Colony 
 Steamboat Company's Sound steamers, running between New York, Newport 
 
 and Fall River. The cylinder is 
 110 inches in diameter, 12 feet 
 stroke, and, when running full, 
 makes 17 revolutions per minute, 
 scale 16, steam at the moment of 
 taking, 23 pounds. 
 
 The demonstration has been 
 made only upon one diagram. The 
 admission line is a little late upon 
 the right hand, the steam line is 
 perfectly satisfactory, carrying 21 
 pounds almost to the point of cut- 
 off and cutting off at barely 20 
 pounds pressure. In this case the 
 demonstration has been made inside 
 the center of expansion for the pur- 
 pose of putting the engine to a dis- 
 advantage, if it was not handling 
 steam correctly. The valve closes 
 at D, on C; the line C has been 
 broken to prevent a confusion with 
 the steam line of the diagram. A 
 few inches to the right of D the 
 valve commences to close. From 
 the time the valve commences to 
 close until it does close, the piston 
 only travels 5f inches. The expan- 
 sion line is very nearly a perfect 
 one; the difference is so exceed- 
 ingly small that there is nothing 
 in practice to find fault with. The 
 release might be improved by open- 
 ing a trifle earlier. The condenser 
 
 takes hold with seven pounds and runs down to eleven before reaching 
 half-stroke and to almost twelve on the last part of the stroke. If the 
 engine released a trifle earlier, a little more compression would be the re- 
 
 
 \ 
 
 41- 
 
 \ 
 
 /C3I 
 / 
 
 FIG. 12(5. 
 
TWENTY YEARS WITH THE INDICATOR. 193 
 
 suit, and if the compression were increased slightly we believe it would make 
 the engine run steadier, but this matter of release, vacuum and compression, 
 is so entirely a part of the engineer's fancy, that so long as the engine runs 
 quiet, they do not mind it, and so few of them are furnished with indicators 
 that they really have to run the engine by their eye and ear, which is not 
 exactly to the credit of the owners, nor in all cases to the owner's profit. For 
 some unexplained reason there is a difference between the right and left-hand 
 diagrams. It may have been caused by a little variation in the steam press- 
 ure between the times of taking from the different end of the cylinder, or 
 what is much more likely to be the case, the bottom or left-hand very likely 
 opens the valve wider, and it certainly opens it a trifle sooner than the top 
 end or right-hand diagram. The upper line represents boiler pressure ; the 
 approximation is very close indeed on the bottom, and the amount of pressure 
 realized on the top end is maintained very nicely, and for that reason we sup- 
 pose it must be that the valve opens a trifle late and does not open fully. 
 Practically the diagrams are very fine. 
 
 Few people have any real idea of the amount of power involved in such 
 diagrams. Every pound of mean pressure on this engine at the speed it was 
 running at the time these diagrams were taken, gives 117^ horse-power, the 
 piston traveling 408 feet per minute ; figuring these diagrams, we find the 
 top end yields 2771.143 horse-power, while the bottom end gives 2747.209 
 horse-power ; a little difference in the ends makes a very large difference in 
 horse-power, and also makes a very considerable difference in the economy of 
 the run. We have no data to give us the exact coal consumption of this ship. 
 The release on the bottom at E is hardly as good as upon the other end of 
 the cylinder, the realized vacuum at F being eight pounds only. The engines 
 of the Providence are fitted with the Sickles cut-off, and show a very decided 
 contrast in closing with those using the rounded wiper cam, and decidedly to 
 the advantage of the engine. 
 
 LESSON LXIY. 
 
 LARGE LOW-PRESSURE ENGINE. ANOTHER SOUND STEAMER. 
 
 Fig. 127 was taken from the new steamer Pilgrim of the Old Colony 
 Steamboat Company's New York and Fall Eiver Line, after she had been run- 
 ning a few months. The dimensions of her engine are, cylinder 110 inches 
 in diameter, length of stroke 14 feet, speed at regular duty 17 revolutions 
 per minute, or 476 feet of piston travel per minute ; the area of the piston is 
 
i 9 4 TWENTY YEARS WITH THE INDICA TOR, 
 
 9503.34 inches, giving as a result 137. 078 horse-power for each pound of mean 
 pressure. The diagram is taken with a 24 spring. 
 
 The line C represents boiler pressure at the moment of taking, which is 
 43 pounds. The demonstration in this case is made on the bottom end, from 
 the base line A, using the parallels B B, showing the point of cut-off on C, 
 at the intersection of C D. The expansion line, it will be noticed, runs down 
 very closely to the actual line of the instrument after the valve gets entirely 
 closed. That there may be no misunderstanding with reference to the line 
 D, it may be explained that the intersection of D with C shows where the 
 realized pressure should have been cut off to produce the amount of power 
 from the pressure at the point A. As a matter of fact the steam valve did not 
 close at the line D, for the pressure, it will be seen, drops away six pounds 
 between the line C w r hich is realized pressure, and the dotted line of the in- 
 dicator, showing the difference between the indicated pressure and the boiler 
 pressure at that point of six pounds. After the piston passes this point, the 
 diagram plainly shows that more steam entered the cylinder, so that the 
 volume which entered was sufficient, had the pressure been realized, to have 
 equaled the effect of the full pressure of 43 pounds, cut off at the intersection 
 of CD. 
 
 We think the valves of this engine might be improved with profit to its 
 owners. To get an idea of the distances represented by these indicator lines, 
 the release opens on the bottom end, expansion line, eight inches before the 
 piston gets to the end of the stroke, and if it opened still sooner it would be 
 better, for after the piston passes the center, we only realize about four pounds 
 of vacuum, and this is increased until ten pounds is realized. When a pound 
 of mean pressure means almost 150 horse-power, every pound of the vacuum 
 has a value in dollars and cents worth looking after. If the release of this 
 engine could be made slightly quicker, say ten or twelve inches, so as to be 
 wide open by the time the cylinder reaches the center or extreme limit of the 
 stroke, then the condenser would sooner get hold, and gave a greater effect 
 for vacuum. The exhaust valve commences to close so that compression 
 begins 25 inches before the piston reaches the bottom of the cylinder. In 
 taking steam, notice the rounded corner where the admission runs into the 
 steam line ; but this very slight difference on this engine means 3f inches that 
 the piston moves before the steam reaches the highest point in the cylinder. 
 We have now 42 pounds of initial realized, while at the point of cut-off from 
 the demonstration we have only 36, terminal pressure at the commencement of 
 release is ten pounds above atmospheric. This valve is slow in its opening 
 and most decidedly too slow in its closing, with regard, at least, for the engine 
 or the economical handling of the steam. 
 
 The top diagram we have made no demonstration from, leaving it with- 
 out any confusion of lines for a close study, and it has some points of superi- 
 ority over that of the bottom. Its admission and steam lines are decidedly 
 better ; the release is not quite as quick, and the compression is not quite as 
 much. Excepting the steam valve on the top end, all the valves of this engine 
 could be quickened with benefit to it and its work. To get a proper idea of 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 195 
 
 the advantage of handling these valves correctly, we have only to refer to the 
 amount of power shown by the diagram in Fig. 127. The bottom end shows 
 4935.679 indicated horse-power, while the top end taken with an intermission 
 of one minute or two, shows 4443.479 horse-power. When we come to handle 
 
 5,000 horse-power of steam in a 
 single cylinder and with a single 
 steam and exhaust valve, it be- 
 comes very necessary to be careful 
 in the adjustment, not only for 
 the economy of steam, but as well 
 for the wear and tear of the en- 
 gine. Compare Fig. 127 with 
 Fig. 126 ; the steamer Providence 
 makes the best use of steam, being 
 fitted with the Sickles cut-off and 
 the Pilgrim with the Stevens. 
 These cylinders are very large and 
 the more perfect the adjustment 
 of the valves, the finer work and 
 consequently higher grade of econ- 
 omy will be produced. All these 
 engines are fitted with the old- 
 fashioned side-pipe, indicator cock 
 in the middle, and we hope some 
 day steam engineers will progress 
 out of this absurd, incorrect and 
 misleading notion. The day has 
 gone by, when the width of a 
 man's thumb will do in adjusting 
 steam machinery, and the interval 
 of time on an engine making only 
 17 revolutions per minute, or 476 
 feet of piston speed in that min- 
 ute, which is required for the 
 steam to pass through into the 
 indicator, is quite misleading as to 
 the actual position of the valves. Compare Figs. 116 and 117, on a small, 
 quick-running engine, notice the difference in position between the three-way 
 cock and the direct attachment, and multiply that difference by the difference 
 between the 14-inch cylinder and the 14-feet cylinder, running 17 revolutions 
 instead of about 225. In all these steamship diagrams, it has been absolutely 
 impossible to get a short connection with the end of the cylinder, so as to show 
 the actual position of the valves. 
 
 FIG. 
 
TWENTY YEARS WITH THE INDICATOR 
 
 LESSON LXV. 
 
 AN OVERLOADED ENGINE. 
 
 Fig. 128 was taken from a Buckeye engine in the wire mills of a large 
 steel works. Diameter of cylinder is 16 inches, stroke 32 inches, 95 revolu- 
 tions per minute, 100 pounds boiler pressure, scale 60, indicating 2404- 
 horse-power. 
 
 There are only two objects to be attained by showing such a diagram as 
 Fig. 128 ; the first is to show the excellent handling of the steam by the 
 valves on an engine indicating 90 per cent, more than it was ever intended by 
 
 Fm. 128. 
 
 the builders, taking the rating of the engine at 125 horse-power and adding 90 
 per cent, to it ; the other reason is to show how extremely inconsistent the 
 owners of steam engines are in asking a load equivalent to almost double its 
 rated power. Out of a hundred pounds boiler pressure, the engine has an 
 initial realized pressure of 96 pounds, cutting off between 95 and 96 pounds 
 pressure at the actual point of cut-off from the demonstration. The theo- 
 retical curve in this case follows the expansion line almost exactly, and it is a 
 wonder how the engine relieves itself in exhausting from a terminal pressure 
 of 46 pounds above the atmosphere, and yet the engine exhausts with a back 
 pressure of about two pounds. The terminal pressure is almost exactly 
 identical on both ends ; there is an extremely small variation by the planim- 
 eter in the area of the two ends, and taken all in all, it may be considered as 
 a first-class accomplishment in doing such a large amount of power. It is a 
 credit k> the builders, but no credit whatever to the owners of the machine 
 who will abuse a good engine like this. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 197 
 
 The practice of overloading is becoming too common. A number of very 
 bad accidents have occurred within the past few months, and steam engine users 
 may by-and-by become accustomed to the rational use of an engine and the 
 proper care of it as well. 
 
 LESSON LXVL 
 
 HARRIS-CORLISS ENGINE, OVERLOADED FINE CARD. 
 
 Fig. 129 is taken from one of a pair of Harris-Corliss engines, running- in 
 the Exposition Cotton Mills, in Atlanta, Ga. Some repairs had to be made 
 
 FIG. 129. 
 
 upon one side, and the other side in producing this diagram, drove the fol- 
 lowing amount of machinery: 4 pickers, 99 cards, 288 slubber spindles, 
 1,320 fine speeder spindles, 11,400 spinning frame spindles, 306 looms, six 
 spoolers, four warpers, with brusher, folder and press. The size of the 
 engine is 24x48, speed 77 revolutions per minute, scale 40, boiler press- 
 ure 83. 
 
 The production of this diagram is a credit to the engineer in charge, as 
 well as to its builder. The engines had been in operation for nearly three 
 years at the time this card was taken. It will be seen that the steam press- 
 
198 TWENTY YEARS WITH THE INDICATOR, 
 
 ure realized is fully up to boiler pressure ; the credit of this is due to the 
 fact that new steam pipes have been put on by the present agent, and the 
 engines are not at all throttled. The engine in this case is doing about two- 
 thirds of the work of the mill with one side, and is starting with 83 pounds 
 of realized pressure, the cut-off closes on 77 pounds, showing that the extra- 
 ordinary demand for steam is much better met than in the average supply 
 pipe, or that the capacity of the feed pipe is fully up to a large increase of 
 load over the regular power of the engine, when both sides and its regular 
 load are running. The expansion line by the demonstration shows but an 
 exceedingly trifling variation at that point, and the terminal pressure is almost 
 absolutely correct. A little earlier release would, perhaps, avoid the small 
 amount of back pressure shown. The compression is sufficient to keep the 
 engine working smoothly and the steam line is practically correct. 
 
 This is as fine a diagram as we may expect from practice, and in this 
 particular case the engineer of the mills has given a great deal of attention 
 to the adjustment of valves by the indicator, w r hich has been backed up by a 
 good mechanical knowledge and ability, as well as good common sense. The 
 horse-power is 390.2509. This is another case of overloading by reason of 
 necessity, but it is not in excess of the ability of the engine to do it very 
 economically, and correctly as well. The ends of the engine vary less than 
 one horse-power in total amount of load. 
 
 LESSON LXVH. 
 
 THE LATEST TRIPLE COMPOUND STEAM ENGINE. 
 
 The diagrams in this lesson are from one of the latest specimens of 
 marine, triple compound engines, having a high-pressure cylinder in the center 
 with a compound fore and aft. The high-pressure cylinder is 71 inches 
 diameter, six feet stroke, running 70 revolutions per minute, boiler pressure 
 110, scale 40. Fig. 130 is from the high-pressure cylinder, in which J, I, 
 represent respectively the base line of our demonstration for the top and 
 bottom diagrams respectively. The line C is that of initial or realized press- 
 ure, D is the line of boiler pressure, A, B are respectively the points of cut- 
 off, A for the top cylinder, B for the bottom, their intersection with the line 
 C, marking the point at which realized pressure was cut off practically, to oc- 
 complish the pressure at J, I, respectively, at that point in the stroke. The 
 
TWENTY YEARS WITH THE INDICA TOE. 
 
 199 
 
 top diagram of this engine is somewhat peculiar, and the line A, which is, 
 properly speaking, tlie volume of steam from H to A, which was used in the 
 bottom of the cylinder, is in this case used to show where the valve was sup- 
 posed to cut off from the staff of the engine ; it is found by the demonstration 
 to be entirely misleading, as the terminal pressure is 12 pounds below the 
 real theoretical line, or below the actual point of cut-off from the steam con- 
 sumed. The line A then becomes the volume of the cylinder from H to A, 
 which was actually used at the initial pressure C to accomplish the result 
 which is given by the actual line of the instrument, the steam and expansion 
 lines of which are shown by dotted lines. The motion of the valve is a little 
 late in admission on both ends, the bottom carries steam farthest and ac- 
 
 FIG. 130. 
 
 complishes the most work, the top end cylinder's pressure falls off more than 
 in the case of the bottom, and the actual line of expansion from B, C shows a 
 near approximation to the line of the instrument on its expansion from the 
 time when the two lines run on nearly together ; on the bottom end the line 
 approximates reasonably close. But what shall we say to the loss of press- 
 ure, which is 13 pounds between the initial and the boiler pressure, and 10 
 pounds between initial and the line of the indicator at the point of cut-off, or 
 23 pounds below the boiler pressure at the point of cut-off on the top ; on the 
 bottom end 30 pounds is lost from boiler pressure and 17 from initial press- 
 ure at the point of cut-off. The average pressure in the receiver from the 
 high-pressure cylinder is from 22 to 24 pounds above the atmosphere. The 
 power developed by the bottom is 5449.5 horse-power, by the top 5054.61 
 
200 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 horse-power, taking the actual line of the indicator. If this cylinder had cut 
 off boiler pressure at the intersection of the two lines with D, it would have 
 added to the bottom, all other being the same, 1184.675 horse-power, with the 
 same expenditure of steam, and to the top would have added 1693.64 horse- 
 power. This gives then an idea of the efficiency of the engine. The release 
 
 is excellent, and we have some doubts 
 as to the exact accuracy of these 
 diagrams from several minor points, 
 and we believe the conditions under 
 which the engine is working would 
 be more reliably shown by an un- 
 proved indicator ; these are the same 
 features shown in a previous lesson, 
 where a contrast is shown as between 
 the old-fashioned instrument and the 
 new Thompson. 
 
 Fig. 131 is taken from the for- 
 ward low-pressure cylinder 105 inch- 
 es in diameter, six feet stroke, 70 
 revolutions, spring 16. In this case, 
 D represents the receiver pressure 
 from the atmospheric line 23 pounds ; 
 the top end of this cylinder real- 
 izes 17^ pounds, which falls off at the 
 point of cut-off to 15, while the bot- 
 tom end only realizes 16 pounds, 
 falling off at the point of cut-off to 
 15. Both ends of this cylinder real- 
 ize much better than the average 
 low-pressure on the compound ; ow- 
 ing to this the vacuum falls to ten 
 pounds at one-fifth stroke and to 1*3 
 pounds at the end of the stroke, or 
 before the exhaust valve is closed. 
 A, A' are the base lines. B is the 
 point of cut-off on line of realized 
 pressure for the top, B' for the bot- 
 tom end of the cylinder. The bot- 
 tom end shows 4102.98 horse-power, the top end shows 4401.92 horse- 
 power, with a very considerable loss between the realized pressure and 
 the pressure in the receiver as shown by the high-pressure diagram. 
 
 Fig. 132 is from the aft low-pressure of compound, cylinder same size as 
 the forward cylinder, same scale. This cylinder for some reason shows a very 
 considerable increase of power and a much better realization of receiver-press- 
 ure on the top end than on the bottom, as the top end, when the valve is fully 
 open, realizes 22 pounds, the bottom end only 19J. The steam valve for the 
 
 FIG. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 201 
 
 bottom end of this cylinder is considerably later than the steam valve for the 
 top end. The point at which steam was cut off is a little longer on the bottom 
 than on the top, but the top end of the cylinder makes the best use of the 
 steam. The release in this case is early, so that a good vacuum is obtained at 
 the very commencement of the stroke, which is held all the way through. A 
 
 very considerable loss is made as 
 between the realized and theoret- 
 ical from the pressure at A, A', 
 which would amount to some hun- 
 dreds of horse-power. The dia- 
 gram from the top of this cylinder 
 gives 4675.25 horse-power, from 
 the bottom 4528.68. 
 
 There is one point with refer- 
 ence to the compound cylinders 
 that must be noticed : the practice 
 is becoming very common of run- 
 ning the low-pressure with the 
 highest vacuum that can be ob- 
 tained. In this case the tempera- 
 ture runs from 236 to about 120, 
 and it is fair to suppose that a 
 certain amount of condensation is 
 effected every time the cylinder is 
 filled with steam after having ex- 
 hausted through the condenser. 
 There may be serious questions as 
 to the real efficiency of the com- 
 pound engine carried to an ex- 
 treme ; and undoubtedly there is 
 a serious lack of economy in work- 
 ing steam as these three diagrams 
 show, as compared with the ex- 
 pense of maintenance, and we 
 doubt somewhat whether this style 
 of engine will very long continue. 
 FIG. 132. The power given out by the boilers 
 
 in the high-pressure cylinder, in- 
 cluding the loss in handling the steam and the resistance in the receiver, is al- 
 most 9,000-horse on each end. That which is used in the compound cylinders 
 makes up a large volume, and the condenser increases the amount realized, but 
 whether this cannot be done by some other combination is a question which we 
 believe engineers shall soon study, and that the key for successfully running a 
 large ship which requires from 12,000 to 14,000 horse-power, as does this one, 
 lies in changing the proportion of the compound engine materially as between 
 the different cylinders, and realizing more heat units with less refrigeration. 
 
202 TWENTY YEARS WITH THE INDICATOR. 
 
 There must be a way of using steam much more economically than is shown 
 by these figures, which are from one of the very latest of marine engines that 
 have not yet made their full record for economy or speed, but which have 
 shown a very large power ; we have not been able to ascertain the relative 
 efficiency or the actual economy when measured by pounds of coal. 
 
 LESSON LXVHI. 
 
 GERMAN BUILT CORLISS COMPOUND ENGINE. 
 
 Figs. 133 and 134 were taken from a Corliss compound engine built by 
 the Augsburg Engine Company, Augsburg, Germany, at work in a spinning 
 mill in that neighborhood. The information is from a series of experiments 
 made by Prof. Schroter of Munich, but the diagrams which we illustrate we 
 obtained direct from the director of the company which built the engine ; no 
 tracings were made use of, but original diagrams. The engine has horizontal 
 cranks at right angles, fitted with a Sulzer valve gear, having a horizontal in- 
 termediate receiver placed below the cylinders and at right angles to them. 
 The high -pressure cylinder is jacketed with live steam from the boiler to the 
 admission valves. The low-pressure cylinder jacket is supplied by a branch 
 pipe from the main steam-pipe, the high-pressure cylinder cannot be shut off 
 but the low-pressure can. The expansion in the small or high-pressure 
 cylinder is regulated by the governor, while the point of cut-off in the low- 
 pressure cylinder is adjusted to any varying point by hand. The air-pump 
 is a horizontal, driven by bell-crank below the engine-room floor. The diameter 
 of the small cylinder reduced to inches, is 14.57 ; large cylinder 24.07 ; pro- 
 portion of cylinders l:2f ; clearance of the high-pressure cylinder 4.3 per cent.* 
 clearance of the low-pressure cylinder 3.1 per cent.; volume of receiver ex- 
 clusive of clearance 11.548 cubic feet ; volume of the receiver to the volume of 
 the low-pressure cylinder 1:1.19; revolutions per minute 71.29 ; mean piston 
 velocity 444.5 feet; stroke 37.4 inches. Reducing motions were used, made 
 of pulleys, fixed at either end of the guide opening in the frame, on the hub 
 of which a small drum was placed to give the indicator barrel proper motion. 
 
 The professor in charge of the test remarks that when the valve gear of 
 steam engines are so arranged as to prevent a loss of pressure, he finds an 
 increased economy of twelve per cent, in the result, and this was taken from 
 two pairs of engines indicating about 300 horse-power, and his basis is made 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 20' 
 
 V 
 
 \ 
 
 from an actual test instead of any theoretical comparison. The deduction is 
 also brought out that when the change of volume between the receiver and 
 the low-pressure cylinder ranges from 0.2 to 1.2 times the volume of the large 
 cylinder, that a mean volume of receiver equal to that of the low-pressure 
 cylinder is the most advantageous. In the original, the metric system is used 
 
 in all dimensions giving 
 us fractions of inches. 
 
 Diagram 133 on, as near- 
 ly as practicable, a 32 scale, 
 shows a rather handsome 
 compression, good admis- 
 sion, a peculiar little jog in 
 the commencement of the 
 steam line, but the realized 
 pressure starts off at eighty 
 pounds, closes on the line 
 B with 70 pounds. The 
 expansion line, based upon 
 the pressure at the line A, 
 follows very closely indeed 
 until past the middle of 
 the stroke, when the indica- 
 ted pressure expansion line 
 slightly exceeds the theo- 
 retical or broken line. The 
 terminal pressure is about 
 the limit of expansion, and 
 the receiver gives a press- 
 ure of 9 pounds to the 
 square inch in the exhaust 
 at the commencement of 
 the stroke, which increases 
 to about 11 pounds at the 
 middle of the stroke, and 
 this pressure is very near- 
 ly continued to the com- 
 mencement of compres- 
 sion. Taking the low 
 pressure cylinder on Fig. 134, its tarts off with a realized pressure of 10 pounds ; 
 basing our demonstration on the pressure at the line A, we find the cut-off 
 to be at the intersection of E B, at which point the pressure has fallen about 
 three pounds. The theoretical and the actual lines run on very nearly togeth- 
 er, showing remarkable efficiency of the expansion, but a considerable loss is 
 realized from the receiver of the pressure given out by the receiver. The 
 vacuum realized is 11 pounds at almost the commencement, and nearly 12 
 pounds at the commencement of compression. 
 
 FIG. 133. 
 
2O4 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 We may judge from these diagrams that the efficiency of the live steam 
 jacket is very considerable, and yet the same argument as in the case of the 
 large compounds comes up in this question, the outside of the cylinder is 
 heated with live steam and the inside is changed a hundred degrees or more 
 by the difference between the realized steam pressure and the vacuum ob- 
 tained at each stroke. There is a 
 somewhat curious theory advanced in 
 the lengthy report originally made 
 upon this engine, which is embodied 
 in the following, referring to the exact 
 proportion as indicated by two differ- 
 ent diagrams : "a phenomenon which 
 goes far to disprove the necessity for 
 employing complicated steam- distribu- 
 tion apparatus to attain nice lines in 
 diagrams ; and that the day is not far 
 distant when a good distribution, by 
 means of slide valves, will be preferred 
 to any of the modern forms of releas- 
 ing gears." 
 
 The illustrations Figs. 133, 134, 
 show us distinctly that there is not 
 that perfection attained in this so- 
 called Corliss engine with some other 
 kind of a valve gear, as will be found 
 by the simple Harris-Corliss in Fig. 
 129, or the Corliss modern compound 
 in Figs. 114, 115. The fact will not 
 have passed from the engineering fra- 
 ternity who are familiar with steam 
 engines, that slide-valve gears, which 
 have given the utmost perfection at- 
 tainable in the nice indicator diagram 
 lines, lately existed in the United 
 States, but that these engines never 
 showed an economy to compare with 
 the Corliss, when economy of fuel, the 
 minimum of repairs and the maximum 
 of durability were all three items con- 
 sidered, and in this combination the Corliss valve gear, up to a reasonably 
 high speed and even in marine service, when properly cared for, has out- 
 stripped every system of valves that has so far been applied, while the 
 slide-valve gear referred to has passed out of use commercially. The feed 
 water per hour as given in this report, with a steam jacket in use, is 14.704 
 pounds of feed water per hour, per indicated horse-power, but many facts 
 embodied in American tests are not reported. Some changes were made in 
 
 00 J 
 
 FIG. 134. 
 
T WENT? YEARS WITH THE INDIGA TOR. 205 
 
 the volume in the receiver which are unimportant here. Taken all in all the 
 diagrams show very good working of steam, but nothing which would induce 
 us to abandon the Corliss valves, or prefer the suggestion in the report upon 
 them, of the adoption of the slide-valve in preference to the liberating valve 
 gear. 
 
 LESSON LXIX. 
 
 MISTAKE IN THE MOTION RESULT. 
 
 Fig. 135 shows a result not to be desired. This was taken from an 
 Armington & Sims engine, where the parties had trouble, and the trouble was 
 in getting more pressure in the cylinder than they had in the boiler, a con- 
 sequent reaction which was not particularly desirable. A is the base line of 
 the demonstration, B the volume of cylinder filled, E boiler pressure, 80 
 pounds, scale 40, C atmospheric line, D absolute vacuum, theoretical line J. 
 The release in the diagram takes place a little before letter J, and directly 
 under J the expansion line crosses or falls under that of the return of the ex- 
 haust which is slightly above atmospheric pressure. The valve apparently 
 begins to close at about half stroke on the exhaust, carrying the compression 
 up very rapidly, and at the point F the compression crosses the line of boiler 
 pressure passing up to G which is 15 pounds above boiler pressure. Here 
 the amount of pressure does not increase any further, but the piston continues 
 its travel to H, at H at the end of the travel of the piston, the pressure falls 
 to I, where the steam valve evidently commences to open, and allows the 
 pressure to pass out, or to equalize itself in such a way that the steam line is 
 not shown as it ordinarily is made by this engine. 
 
 It will be seen at the very outset, the point of cut-off, B E, by the demon- 
 stration, is practically inside of the real line of the instrument, but only for a 
 very little way. The theoretical line K passes through the line of the instru- 
 ment at a trifling advance beyond the line B, falling below it, while before we 
 reach the demonstration line A, the theoretical line is above the actual line of 
 the indicator. It then passes below it before the release, after release it 
 barely touches the expansion line on its return. 
 
 This is a very curious diagram, for the readings are, to a certain extent, 
 negative in every direction. What was the reason ? At the left of the diagram 
 we have drawn the whole cause of the trouble. These makers use a pendulum 
 with an arc of a circle from which the cord is led direct to the indicator. In 
 
206 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 this case, we found the arc of the circle reversed, or the upper dotted line in- 
 stead of the lower shaded line, the point L being in either case the pulley which 
 received the cord from the motion. There is not a single correct line on the 
 diagram ; the motion is distorted precisely in proportion to the reversing the 
 arc of a circle, as shown, M being the center, the cord being led in the angle 
 of the dotted line instead of, as it should have been, from below M or the 
 shaded portion. 
 
 Upon adjusting the motion the diagram assumed its normal appearance, 
 and entirely different from that which is shown. The question may arise in 
 figuring such a diagram as this by the pianimeter, what to measure, from the 
 fact that there are negative quantities at each end of the diagram. We have 
 
 i5~H\ 
 
 FIG. 135. 
 
 therefore drawn two arrows, one on the expansion and one on the compression 
 line, to show the direction which should be taken. Locate the pianimeter 
 properly, start at the intersection of the line at F, follow the line in the same 
 direction that the pencil of the indicator followed it ; starting at F follow the 
 steam line down the expansion line in the direction of the arrow, at J cross 
 the expansion line, come up, again recross the expansion line under J, follow 
 the exhaust and compression line in the direction of the arrow, cross F up to 
 G, to the right to H, down to I, then down to F. This will give you the 
 area less the negative quantities or resistance. Now as the negative quantities 
 increase the length of the diagram, the total length from the extreme at I to 
 the other end at the left of J, must be taken into the account, so as to get the 
 correct ordinate which, reduced to the scale, is the mean pressure. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 207 
 
 LESSON LXX. 
 
 DEFECTS WHICH ARE SHOWN BY THE INDICATOR. COMPARISONS. 
 
 The various adaptations to which the indicator can be put, the certainty 
 of the readings, if properly interpreted, the different defects which may be 
 pointed out with absolute certainty, are very frequently lost sight of, more 
 especially when, as has been stated in this volume previously, this particular 
 part or adjustment, or indications for defects, has been kept in the hands of 
 men who have not understood it any too well themselves, and have not been 
 fully conversant with the details of the machinery which they have attempted 
 to criticise, 
 
 FIG. 136. 
 
 Take Fig, 136, and taking away the theoretical dotted line D, almost any 
 engineer or engine builder would pronounce it a very fine-looking card, but 
 the purpose of this volume is to give information. We must, therefore, 
 resort to our demonstration, and, if we take the base line A, the scale of the 
 diagram being 30, we find we have above absolute vacuum, a pressure of 19 
 pounds plus. Upon making the demonstration, we are rather surprised to 
 find that the point of cut-off is located at the intersection of B, C, the dis- 
 tance from the left-hand vertical line to B, representing the volume of the 
 cylinder in comparison to the whole length of the stroke, which was filled 
 with steam at the initial pressure of 40 pounds, or absolute pressure of 54 
 plus. 
 
 Taking B as our starting point, and our readers must not forget that 
 these are two different problems in geometry, the first problem closes with 
 the erection of the point B, C, we then adopt the second problem, which is to 
 lay out the hyperbolic curve, by the means already described ; this gives us 
 
208 TWENTY YEARS WITH THE INDICATOR. 
 
 the long-dotted line D, which it will be seen starts 10 pounds above 
 the actual line of the indicator as it crosses the line B, gradually near- 
 ing the actual line of the indicator at A, and shortly after crossing 
 below the actual line of the instrument. We find that the end of the 
 expansion line, which is under the atmospheric line is three pounds, actual, 
 above the theoretical, or 13 pounds above the absolute vacuum, instead of 10 
 as it should be. There are several theoretical questions which enter into 
 this, that it is not our purpose to discuss, for they have little bearing upon 
 the practicability of the application of the indicator or its readings. Our 
 demonstration is based upon the fact that the expansion line in the cylinder 
 is entirely settled at the point A, or about half-stroke on the expansion ; or, 
 in other words, that it is less liable to be disturbed here. Now, the point A 
 is a positive fact, and if steam expands, according to Marriotte's law, or 
 Regnault's demonstration, or Joule's experiments (and these are acknowledged 
 as approximate to the fact) then the actual pressure at A gives the point B C, 
 as where the initial pressure of 40 pounds should be cut off and expanded, 
 according to these different authorities, to produce the pressure at A. In 
 this case the point A is higher on the expansion line than it should be if the 
 steam had been properly cut off previous to B, showing that something must 
 have occurred while the piston traveled from B to A, which admitted steam 
 into the cylinder after the cut-off valve closed, as is shown by the indicator 
 line. Now, this may be admitted in so small an amount as to apparently be 
 imperceptible, and the demonstration is the only way of ascertaining what 
 does occur. In this case, the steam was admitted after the cut-off valve ap- 
 parently closes, but in such a small amount that at A it is sufficiently high 
 above what it should be, to throw the point B forward on the line C, and the 
 other end of the expansion line quite corroborates this, the sequel proves the 
 correctness of the application. When the engineer who submitted the dia- 
 grams to us, was allowed an opportunity to take down his engine, he found a 
 bad leak under the steam valve, so much so that he had to draw-file the end 
 bearing of the valve, or shoulders of the valve, to let down upon its seat, and 
 to stop the leak, which was visible when the cylinder head was removed. 
 
 The old-fashioned way of taking the terminal pressure and working back, 
 would be a very wrong practice in connection with this diagram, and there 
 need not be any confusion in the minds of any of the readers of this work, 
 who correctly apply the demonstration to any diagram, if the few simple 
 directions are followed which are so plainly given. It will at once settle the 
 fact, that something is wrong, without stopping to experiment. 
 
 If, now, we take up the case of another series of complications, defects 
 and conditions not desirable, we will refer to Fig. 137, the scale of which is 
 40, steam pressure at the time of taking, 82 pounds. This was a new engine 
 built to run 83 revolutions, and was sent to us from several hundred miles 
 away. The actual diagram is reproduced ; A representing the base line of our 
 computation, B the point of cut-oft at which the initial pressure C of 50 
 pounds was equal to cutting off in the amount of steam used to produce the 
 pressure at A. Had the theoretical line F been run to the boiler pressure 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 209 
 
 line D, it would have shown that the use of about one-third the amount of 
 steam, properly cut off, would have performed much more work, if it had 
 not been for other defects, of which we shall shortly speak. The diagram, 
 in this case, shows on its cut-off and expansion line, an exceedingly close 
 
 approximation to the side of an 
 old-fashioned iron wedge. It is 
 extremely difficult to locate the 
 point of cut-off, or to find out 
 where the expansion line begins, 
 and the approximation to any- 
 thing which is valuable or eco- 
 nomic is so entirely remote that 
 we will not waste further time 
 upon that portion of the diagram. 
 The theoretical line F shows a 
 close approximation of the termi- 
 nal pressure as between the theo- 
 retical and actual, demonstrating 
 that an amount of steam bounded 
 by the line B, cut off on C, was 
 about equivalent to the amount of 
 steam used, taking the assumed 
 line F with the actual line of the 
 instrument. 
 
 In this case, we find the ex- 
 treme terminal about in unison 
 with the theoretical, but back of 
 that where we suppose the ex- 
 haust valve commences to open 
 (for the lines are indistinct and 
 indefinite) it is several points 
 higher. But the main feature now 
 is, the trouble in getting rid of the 
 exhaust steam, one line is dotted 
 and the other is solid ; they have 
 both a peculiar hump, showing 
 either that the exhaust passage is 
 clogged by insufficient ports, or 
 FIG. 137. what is more apt to be the case, 
 
 and what we at once decided when 
 
 submitted to us, that the steam from one end of the valve passed into the ex- 
 haust about the center of the stroke, for a brief space of time, increasing the 
 back pressure. A variety of theories were advanced, one of which was that the 
 valves were not tight, but would in time wear down to a seat. Whenever an 
 engineer finds this kind of a diagram, the shortest way out is to abandon the 
 whole thing, or condemn the engine and get it into the scrap-pile as soon as 
 
2 10 
 
 TWENTY YJKAfiti WITH THE INDICATOR. 
 
 possible. It is so exceedingly extravagant in its use of steani for the small 
 amount of power, and considering the fact that it was intended as an auto- 
 matic cut-off engine, that it is unworthy further attention, its only purpose of 
 introduction being that it is an incident in practice which may be valuable to 
 some one in trouble. 
 
 As the best way to judge between bad and good practice is by com- 
 parison, we introduce into this lesson another diagram, which was not taken 
 by the Thompson indicator, partially to show the expansion line, about which 
 more or less argument has been made among indicator makers for the last few 
 years, and also to contrast it, with the circumstances all stated, with Figs. 136 
 and 137 in this lesson, and the four succeeding figures in the next lesson fol- 
 lowing. 
 
 Diagram Fig. 138 is an exact reproduction, taken from one of George H. 
 Corliss' steam- jacketed new pattern engines, boiler pressure 75, 30 inches 
 
 D 
 
 ,-! 
 
 FIG. 138. 
 
 diameter of piston, 72 inches stroke, 54 revolutions, 40 scale. This engine is 
 driving a flour mill in the City of New York, has been running fy years, about 
 140 hours per week, and from six o'clock Monday morning until six o'clock or 
 midnight Saturday night, the throttle valve is never closed. The engine is 
 grinding about 1400 barrels of flour every 24 hours and its weekly run 
 amounts to 143 hours each week. The indicated horse-power is about 575 
 H. P. We have 66 pounds initial pressure out of a boiler pressure of 75 ; 
 the line A is the base line of the demonstration which gives B D as the point 
 of cut-off on D, or the volume of the cylinder represented by the dotted line 
 C D in proportion to the whole length of stroke, as that portion of the cylin- 
 der which was filled with steam at initial pressure to accomplish the work. 
 Making the demonstration from A B, by means already described, we have the 
 points a, a, a, etc., showing the exact line of the theoretical in comparison 
 with the actual. The line D is drawn triflingly above the actual line of the 
 (nstrument, or nearly two pounds above, in order to show the actual record of 
 the indicator ; for that reason, a slight difference is made in the position of 
 
TWENTY YEARS WITH THE INDICATOR. 211 
 
 the lines, showing the points through which the theoretical curve runs, but 
 whatever that difference may be, it is so near to the width of a line as to be a 
 feature of no possible account in variation, and would be hardly recognizable 
 had the line D been drawn directly through the steam line of the diagram. 
 
 There is no mistake about the work which this engine is doing, provided 
 the indicator is correct, and it is hardly probable that any great, difference 
 exists with the action of the indicator ; but there is a point in connection with 
 this expansion line which is treated of in the next lesson, to which our readers 
 will do well to pay careful attention, and that is in relation to the change of 
 pressure, volume, temperature, etc., and whether the expansion line in this 
 diagram is an absolute reproduction of fact ; this will be illustrated in the im- 
 mediately succeeding lesson. 
 
 With regard to adjustment of this engine, little can be said other than if 
 we were ourselves adjusting the valves, we should give it a slightly earlier re- 
 lease, so as to let the exhaust line down where it belongs, and this in turn 
 would give us the fine dotted line for compression, which we should much 
 prefer to see. This diagram was not taken with any preparation, change or 
 otherwise, but was taken while the engine was at its regular work, and speaks 
 not only for its builder, but as well for the care which has been given it by 
 the chief engineer. This shows an exceedingly close approximation as be- 
 tween practical and theoretical, where everything is in working order, well 
 taken care of, doing severe work and running foi practically twenty-four 
 hours per day, six days each week. No new valves and no lost time are yet 
 charged to this engine. 
 
 LESSON LXXI. 
 
 AN EXPERIMENT WITH INDICATORS ON THE SAME END OF THE SAME 
 
 CYLINDER, AT THE SAME TIME, WITH THE SAME 
 
 SPRINGS IN EACH. 
 
 Fig. 139 was taken from a 9^x12 Armington & Sims engine, runningr 
 276 revolutions per minute, 80 pounds of steam, 40 spring. The pattern of 
 indicator with which this was taken, is what is now known as the old Thomp- 
 son, with what was practically the Richards parallel motion, or a very much 
 heavier motion than that which is used on the Improved Thompson of to-day. 
 Some of the indicator makers have put out some very curious literature in 
 the way of circulars, showing the defects of each other's indicator, according 
 
212 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 to the figures which accompany the circulars or pamphlets which have been 
 spread broadcast. The experiment which we are to record here, was made for 
 the purpose of ascertaining what the indicators will do, in actual practice ; 
 and we desire at this point to call the attention of our readers to what we 
 have very radically differed from many of the engineers, with reference to 
 the expansion line of the instrument, and the record which is made by the 
 action of the indicator on particular points, and we are glad, therefore, to 
 show Fig. 139. At A we have a realized pressure of 76 pounds, at B 35 
 pounds, at C 16 pounds, at D 9 pounds, and at E the expansion line crosses 
 the atmospheric line, and when the exhaust valve opens at the termination 
 of the stroke, the pressure rises gradually until about one pound above, when 
 it returns across the expansion line at E, passing along, gradually increas- 
 ing to F as the valve is closing, until at F it is closed, when the pressure 
 rises rapidly. This diagram is one of many, and is taken without any par- 
 ticular selection. 
 
 FIG. 139. 
 
 We will now refer to Fig. 140, which was taken by another indicator, 
 with the same spring as stated above. The two diagrams, 139 and 140, were 
 taken on the same stroke of the engine, with the same steam pressure, each 
 indicator run by a separate cord, and a slight difference in the length of the 
 cards is shown. The peculiarity of the two cards is perfectly perceptible to 
 any one. In Fig. 140, we start off at A with a pressure of 65 pounds initial. 
 At B we have 51 plus, at C 48, at E 27, at F 15, at G 8. A, however, is the 
 height of the compression line which falls off to D, rebounds to B, comes 
 down to C, during the time that the valve is opening, and then starts off to 
 the left, making the first curve in the steam line. The rebound of pressure, 
 by the sudden expansion, increase of volume, and the struggle between the 
 elements and the speed carry the expansion line below the compression line 
 on the card, and when the next fluctuation in pressure occurs, at E, in the 
 forward movement of the engine, and the rapid expansion and falling of 
 pressure, the expansion line crosses the compression line, making the second 
 wave at D ; dropping to F, it covers, but does not cross, and then advances 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 213 
 
 again, the oscillations becoming less and less perceptible, until they barely 
 cross the atmospheric line at the end of expansion, and come back upon the 
 atmospheric line alone until the compression line is made. There is such a 
 radical difference as between the two diagrams that one must be nearer right 
 than the other, and one must be exceedingly far from correct. We have 
 settled in our own mind that 139 shows the position of the valves, and the 
 action of the steam. 
 
 Bat there are other elements to be brought into this lesson. It has been 
 upon one part of the indicator-using fraternity, their earnest endeavor to rec- 
 oncile all differences of position, all fluctuations of working, to the idea of 
 making a smooth card, for which see 140, 142. We have frequently had cause 
 to say editorially, and before different audiences, that we had been unable to 
 reconcile all these differences which do take place in the steam cylinder of an 
 engine, to the theory that a steam engine indicator must of necessity produce 
 
 FIG. 140. 
 
 the true hyperbolic curve, or the nearest approximation to it, with a correctly 
 working indicator. Inferentially we have condemned this as all wrong, and 
 believe that the various elements entering into the expansion line of high 
 speed diagrams, if correctly delineated by the indicator, will very much more 
 approximate 139 and 141 than they will 140 and 142, both as to the position 
 of the valves, and actual record of the working of the steam in the cylinder. 
 If we take 139, we find from A to B a change of 41 pounds pressure, in 140 we 
 find from C to E a change of 21 pounds pressure. If we take the tempera- 
 ture of the steam at A on 139, we find it 308.4, at B it is 259.3, while at C 
 it is only 216.3. Let us now see what the volume in each case is. At A the 
 volume is 377, at B 764, at C 1572. If this were the only element it would 
 be quite enough to produce the radical changes shown in 139. If, now, we 
 refer to the dotted lines, showing the friction load, in Fig. 142, we find there 
 a diagram taken with a stiffer spring, which almost absolutely ignores any 
 fluctuations in temperature, pressure or volume. Referring to the solid line 
 in 141, which represents the friction card, with the Thompson indicator, with 
 
2i 4 TWENTY YEARS WITH THE INDICATOR. 
 
 the same spring as 142, we find these differences very elegantly shown in the 
 load, and plainly perceptible in the friction card, which is enclosed within the 
 other. Both these diagrams in 141 and 142 were taken by preparing for it 
 beforehand, so as to throw a break upon a pulley, properly connected, raising 
 the load from the friction to the amount shown, in the shortest space of time 
 consistent with safety to those employed. Now, if nothing except the volume 
 and the temperature were to be considered, we have then elements of immense 
 disturbance, as shown by the figures quoted. In Fig. 139 the volume in- 
 creases in the fraction of a second from 377 to 20,890 at E ; while in Fig. 140 
 the volume increases from 434 to 20,890, and the temperature diminishes in 
 the fraction of a second from 308.4 to 102. But if we refer to Mr. Charles 
 T. Porter's book, entitled the " Bichards Steam Engine Indicator," which has 
 been in oar possession for fifteen years at this writing, we find the most re- 
 liable and best tabulated data that we have ever yet had access to, with ref- 
 erence to the speed of the crank at different degrees in the steam engine, as 
 well as to the speed of the crank as compared with that of the piston. We 
 
 FIG. 141. 
 
 find the following statement with reference to the rotative force exerted 
 upon the crank, being the same for equal divisions of the diagram : 
 
 " If the reciprocating parts of engines were without weight, so that the 
 pressure of the steam was always exerted upon the crank precisely as it is on 
 the piston, then the rotative force on the crank of the steam pressure would 
 be equal for equal divisions of the diagram measured at any part of the 
 stroke. This is often denied, and still more often doubted. Being a fact, it 
 ought to be placed beyond either denial or doubt. The motion of the crank 
 is supposed to be uniform, passing through equal arcs in equal times, the 
 motion of the piston, on the contrary, is, first, scarcely two-thirds that of the 
 crank, being to the latter in proportion of 1:1.5708, and, second, it changes 
 at every point of the stroke. At the instant that the crank is on the dead 
 center the piston has no motion. Then its motion, at first infinitely slow, 
 becomes gradually accelerated, until the velocities of the piston and the crank 
 are equal, when it begins to be retarded, the ratio of retardation increasing 
 until on the opposite center its motion has ceased. But whether the revolu- 
 tion of the crank is uniform or not, as in fact it can never be absolutely, 
 since then the fly-wheel would cease to act as a regulator, and might be dis- 
 pensed with, the motion of the piston has a fixed relation to it, being equal 
 
TWENTY YEARS WITH THE INDICATOR. 215 
 
 (if we disregard for the present the effect of the angular vibration of the con- 
 necting rod) to the versed sine of the angle which the crank makes with the 
 center line. The study of the table of versed sines will explain all about it. 
 We will employ the two extremes for illustration. The versed sine of 1 is 
 .0001523; the difference between the versed sine 89 and that of 90 is 
 .0174524. Therefore, the length of the crank, or of the half stroke of the 
 piston, being 1, while the crank is traversing the first degree the piston 
 moves the distance .0001523, and while the crank is traversing the ninetieth 
 degree the piston moves the distance .0174524, which is nearly 115 times 
 greater than the former. The rotative effect of a force varies also as the 
 versed sine of the angle at which it is applied. Therefore, the effect of the 
 rotative pressure of the steam on the crank while it is traversing the ninetieth 
 degree is 115 times as great as while it is traversing the first degree, but 
 also the piston moves in the former case 115 times as far as in the latter. It 
 follows, therefore, that equal movements of the piston, or equal portions in 
 the length of the diagram, at any part of the stroke, represent equal rotative 
 effects upon the crank." 
 
 FIG. 142. 
 
 "We have made this lengthy quotation, first, because Mr. Porter has so 
 well said, and has substantiated his assertion by indisputable fact, and, sec- 
 ond, while we are not dealing in this lesson with the rotative force on the 
 crank we are dealing with the speed of the piston, and will now drop our 
 digression and return to the subject in hand. Added to the extreme range in 
 temperature, as well as the tremendous increase in volume, we have now 
 another factor which shows us that the difference between the travel of the 
 piston through the first degree of the stroke and the last degree of the stroke 
 is 115 times ; we have then precisely what we require to substantiate our 
 own assertion, that if the indicator is to be the exponent, or is to truly record 
 what is actually done in the cylinder, then it must also record these extreme 
 ranges of fluctuation in pressure, volume, temperature, all of which are gov- 
 erned by the varying speed of the piston. We have, therefore, just these ele- 
 ments ; referring to diagrams 139 and 141, from A to D, in 139, the speed of 
 the piston is constantly increasing, the pressure of the steam, as shown by 
 the indicator diagram, falls very rapidly, the temperature decreases very fast 
 indeed, while the volume increases at a tremendous rate ; the speed of the 
 engine, being 276 revolutions, reduces the time in which this diagram is made 
 to about one-tenth of one second, or that portion of it which lies between C 
 
2i6 TWENTY YEARS WITH THE INDICATOR. 
 
 and D is reduced to fa of a second 12 1 00 of a minute approximately, more cor- 
 rectly being y-jVr a^d when we add to this the fact that the speed of the pis- 
 ton is an ever- varying amount anything but constant we do not hesitate to 
 state that while our assertion may have been doubted or denied, it is sus- 
 ceptible of proof, and that proof we believe is offered in these elements be- 
 yond dispute, if the facts are considered. 
 
 Figs. 141 and 142 were taken with a 60 spring to ascertain what differ- 
 ence, if any, would be shown as between two instruments on the same engine, 
 at the same speed, with the same steam and spring, and at the same instant 
 of time ; 141 was taken with the Thompson instrument, with the new or Im- 
 proved Thompson, with the light parallel motion. In 141, we have dotted 
 the outside or total load and drawn the friction of the engine, so far as we 
 could do, in a solid line. In Fig. 142, we have been obliged to reverse this 
 operation, owing to the fact that the friction crosses the initial. The two 
 diagrams may be treated from any standpoint, and only require a careful 
 observation to convince any person, who is disinterested, where the actual 
 position of the valves and the working of the steam is shown. To our 
 own idea 141 shows every element of accuracy, while 142 shows quite a 
 different result for power and position of the valves ; and we may in this 
 connection, perhaps, with perfect propriety, quote again from Mr. Porter's 
 book, as follows : 
 
 ''VIBRATIONS OF THE SPRING. 
 
 " Sometimes at very high speeds, or with very sudden action of the steam, 
 the spring of the indicator is put into vibration. If the line produced by 
 these vibrations is a waving line, quite free from angles, this is an evidence 
 that the action of the instrument is frictionless, and the mean of the vibra- 
 tion gives a true line." Almost on the same page Mr. Porter makes this state- 
 ment : " There are no vibrations or pulsations of steam in the cylinder ; all 
 appearances of this kind, on the expansion curve, are caused by the spring of 
 the indicator being put into vibration by the sudden action of the steam." 
 
 If the vibrations do not occur while the engine is under motion, or if the 
 pulsations are not caused by the conflict in the molecules of steam, or steam 
 and water, as well as the different mechanical forces, then we confess that our 
 steam engine indicator had better be laid upon the shelf instantly, there to 
 remain until we can prove that different mechanical forces, acting as we have 
 cited above, are capable of producing a true hyperbola by means of a spiral 
 spring. Whatever may be the fact with regard to pulsations, we call par- 
 ticular attention to the difference in the outline which shows the position of 
 the valve, as between 141 and 142, while the differences between 139 and 140 
 are quite sufficient for anyone, however unsophisticated he may be in the 
 uses or abuses of the indicator. In our own experience in taking diagrams 
 with different indicators upon the same end of the engine, at the same speed, 
 and under the same conditions, we have found that diagrams showing wavy 
 lines, figure somewhat less power, and give generally a more accurate idea of 
 the working of steam in the cylinder, and that the same indicator also sooner 
 
TWENTY YEARS WITH THE INDICATOR. 217 
 
 responds to any actual alteration made in the valve motion, by showing it 
 upon the diagram, showing that its accuracy extends into this important 
 realm of the functions of the indicator, viz. : position of valves, while the stiff- 
 working indicators do not show it as soon nor as delicately. 
 
 LESSON LXXII. 
 
 EXTREME HIGH SPEED, DIFFERENCE IN INDICATORS. 
 
 The tendency to high speed has led to some very curious developments, 
 and one of the principal claims of engine builders, as well as indicator 
 makers, to-day, is, that their engine, or their indicator, is the most, if not 
 the only, reliable one at high speed. High speed, it has been proved to our 
 
 THOMPSON, No. 2. FIG. 143. 
 
 own satisfaction, has a limit where efficiency ends and extravagance begins, 
 and while we have no purpose in this article to criticise, we must express ou. 1 
 opinion so that we may not be placed on record as advocating the speed (at 
 which the diagrams illustrated in this lesson were taken) for practical 
 purposes. 
 
 These diagrams were taken in the shop of Armington & Sims, Provi- 
 dence, K. I., where they had prepared an engine by increasing the strength 
 of some of the parts of the regulator, and our intention was to have carried 
 the experiment to 700 or more revolutions per minute. Diagram 143 was 
 taken with a Thompson Improved Indicator, No. 2, on small paper barrel, an 
 illustration of which is given with this, which differs from the larger indi- 
 cator only in the size of paper barrel, and some minor changes with reference 
 to the stand, the spring and motion being the same as that in the larger 
 
218 
 
 TWENTY YJEAES WITH THE INDICATOR. 
 
 instrument. This instrument is made with or without the detent motion, 
 generally with the detent motion ; this is a matter which is invaluable to 
 those who are unused to high speeds, or are not familiar with the practice of 
 
 FIG. 144. 
 
 taking indicator diagrams, and it is especially valuable to those who are 
 taking diagrams from the locomotive. Fig. 143 was taken with this instru- 
 ment in April, 1884, at a speed of 536 revolutions per minute, actual count, 
 the regulator being graduated and adjusted for that point. The reader will 
 necessarily have to compare several diagrams, one with another ; for this 
 purpose, with the exception of Fig. 149, we have in this article, dotted the 
 steam line and drawn the expansion line solid in all the figures. 
 
 FIG. 148. 
 
 In Fig. 143, it will be seen that the expansion crosses the atmospheric 
 in the vibrations, and returns again, making a very handsome atmospheric 
 line, and that the compression line crosses the first or largest vibration, but 
 that the steam line is very handsomely shown. Fig. 144 was taken by an 
 instrument from another maker ; it will be seen in this case that there is a 
 very great difference between the atmospheric line and compression line. 
 
TWENTY YEARS WITH THE INDICATOR, 
 
 219 
 
 Fig. 143 was taken with a 50 spring, 144 with, a 40 spring. Fig. 145 was 
 taken with the same instrument as 144, at a speed of 536 revolutions ; there 
 being such a difference between 143 and 144 as to position, that 146 was 
 
 FIG. 146. 
 
 taken with the little Thompson, the spring being changed tc 40, the speed 
 being increased to 562. It will be noticed here that a change takes place in 
 the admission and steam line, which continues through the other diagrams, 
 the motion of the valve being shown as a trifle late, the expansion line hav- 
 ing its peculiarities, but the record being very clear. The steam pressure in 
 146 was 75 pounds. To ascertain what could be done, we again changed the 
 spring to 50, the steam meantime having been raised to 95 pounds, and ob- 
 tained from this change Fig. 147, with the Thompson No. 2, revolutions 562, 
 
 FIG. 147. 
 
 For the sake of experiment, arrangements were then made to add a load 
 to the engine, and Fig. 148 was taken with the Thompson Improved No. 2, 
 steam pressure 92 pounds. The peculiarities in 146, 147 continue with 
 reference to the valve motion, showing it a trifle late ; the compression and 
 expansion lines are very nearly identical, except that the load is increased. 
 Upon 148 we have erected the demonstration from exactly half stroke, the 
 line A being the base line, showing the cut-off to be at B, on C, and for the 
 
220 
 
 TWENTY YEARS WITH THE INDICATOR, 
 
 terrific speed at which it is running, there is a very good showing for the 
 valves as well as the indicator. Having so far determined that the action of 
 the indicator was at least capable of showing changes, an effort was made to 
 
 FIG. 145. 
 
 increase the speed of the engine from 562 to 700, the regulator was changed 
 as much as it was deemed safe and a start was made, producing Fig. 149 
 with the new Thompson No. 2, at a speed of 642 revolutions per minute. 
 Two other cards were produced, and while changing for the fourth one, a piece 
 of the regulator which had been made of steel, straightened out by the strain 
 upon it, and we were treated to an example of solid bodies going off at a 
 
 FIG. 149. 
 
 tangent, and the engine was stopped for repairs. The ordinary speed of 
 this engine is 320 or 330 revolutions ; the action of the regulator shows 
 plainly on 149, with 95 pounds boiler pressure, and an initial of 90:92, the 
 load was made constant, but it is absolutely impossible to engrave the 
 variations which took place, only at the curves in the expansion line. The 
 intention at the outset of this experiment was to try the three indicators 
 which are in the market ; one of them stopped inside of 400, one ceased its 
 
TWENTY YEARS WITH THE INDICATOR. 221 
 
 accuracy practically at 536, or probably below, while tlie third one made the 
 diagrams which we have shown, leaving the little Thompson master of the 
 situation in this experiment. 
 
 We have, since that time, been allowed to test an engine more for speed 
 than anything else, and have succeeded in getting very fair diagrams at above 
 720, but the action of the steam shows plainly that the engine will not 
 become a merchantable or commercial affair, and there is no use in devoting 
 space to that which is not practical ; we do not consider this lesson as one 
 of any particular importance for the student of the indicator, and it is intro- 
 duced more as a curiosity to show the results of a single experiment, upon 
 which we do not place any particular stress, and would not advise any person 
 to buy the Thompson indicator solely upon what is shown in this lesson, or 
 not to buy either one of the other two because of their ill success at this 
 experiment. One of the makers of the engine was present and saw all the 
 experiment. The intention was fully pursued of giving to each instrument 
 every benefit and every advantage, and the results shown are, as nearly as 
 possible, the actual result of the work of the instruments. We do not, how- 
 ever, advise our readers to adopt any such speed, nor do we consider the 
 actual indicator diagram at this speed as an unquestioned performance. The 
 claim has been made that diagrams have been taken at above 1000 ; while we 
 have no reason to doubt the assertions, we consider them simply experi- 
 mental, or in the light of a curiosity, and having no possibility of practical 
 value, unless it be to gratify a whim, which cannot result in any economy 
 to the general steam user, at least with present engines, indicators or 
 mechanism. 
 
 LESSON LXXIII. 
 
 AMERICAN BUILT COMPOUND STEAM ENGINE FOR A RIVER STEAMER, 
 
 The question of simple condensing engines, or of compound engines, for 
 our river steamers has been one upon which a great diversity of opinion has 
 been expressed, and in which the extremes of practice have been worked out 
 within the last few years. Wishing to get data regarding this, we asked and 
 obtained permission to indicate a river steamer's compound engine working a 
 screw, and this steamer is doing the work with about one-half the fuel that a 
 condensing beam engine did it, and is one of the fastest steamers for her 
 class running out of New York. 
 
222 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 Fig. 150 is the high-pressure diagram, taken with a 50 spring, the cylin- 
 der being 30 inches in diameter, 36 inches stroke, making 88 revolutions per 
 minute, with 85 pounds of steam. 
 
 Fig. 151 is from the low-pressure cylinder of the same engine; 56 inches 
 in diameter, 36 inches stroke, making 88 revolutions, scale of spring 10. The 
 diagrams were taken at the same instant of time, two indicators being used, 
 so that they represent what was done on the same stroke at the same instant 
 of time. 
 
 In Fig. 150, A is the base line of the demonstration, which touches 
 through the theoretical curve Gr, the realized steam pressure line F, at B. B 
 represents the volume of steam actually used to do the amount of work at 
 the realized pressure, which is 9 pounds less than the boiler pressure E. The 
 valve in opening, as will be seen, allows the pressure to drop slowly from the 
 line F after the piston has passed but a few laches of its stroke, so that at 
 the point B, on F, the realized pressure by the indicator is 10 pounds less 
 
 FIG. 150. 
 
 than the realized pressure at the commencement of the stroke. We then find, 
 after having passed pretty well toward the end of the expansion line, that the 
 expansion rises above the theoretical to a certain extent. The exhaust valve 
 is somewhat slow in its opening, and the pressure in the receiver at the very 
 highest amounts to between 11 and 12 pounds. The same general features 
 will apply to the valves, both high and low-pressure cylinders, viz., that the 
 opening of the valve seems to be either slow or insufficient, and the pressure 
 gradually drops from and after the time when the valve opens, and owing to 
 this feature it is also slow in closing, and the amount of steam accounted for 
 is considerably in excess of that which is generally considered shown by the 
 indicator. If we refer to 151, taken with a 10 scale, we charge against that 
 cylinder 12 pounds initial pressure, which is the extreme amount shown in 
 the high-pressure cylinder as back-pressure or between the high-pressure and 
 low-pressure cylinder. The lines I and I' represent respectively the steam 
 admission from the receiver to the low-pressure cylinder. If we refer to the 
 line I we see that after the steam is first introduced the pressure is kept at 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 223 
 
 11 pounds above the atmospheric line C for a very small portion of the 
 stroke ; that as quick as the speed of the piston begins to increase, then the 
 pressure of the steam commences to drop away, until at the line B there is 
 only 4 pounds above the atmosphere, and at the point of visible cut-off, or 
 where the valve finally closes, there is only two pounds above the atmos- 
 phere. I', while not making so good a start, has a pressure of almost three 
 pounds at the visible point of cut-off, which is considerably beyond the line 
 B'. Now, what happens ? When the valves of this engine commence to open, 
 the steam is not admitted in proper amount, owing to its low tension, to fill 
 the cylinder at the pressure which' exists in the receiver. The moment the 
 piston starts to move away from the end of the cylinder and the motion of a 
 piston with a short connecting rod, not more than two cranks, accelerates 
 
 B 
 
 D 
 
 B' 
 
 FIG. 151. 
 
 very rapidly then the amount of steam which is admitted grows less and less 
 or is more and more wire-drawn. The steam is cut off at the line B' of the 
 other diagram, as we express it, visibly ; or, that is, the point, almost two- 
 thirds of the stroke, where the steam valve closes and the expansion on the 
 low-pressure cylinder begins. If we go a step further to the line A', which 
 is the base of our computation, we find at that point, only a trifling distance 
 beyond the point 01 cut-off, the pressure above absolute vacuum is about 14.3 
 pounds. Now, had we here cut off the pressure of steam at B to make the 
 theoretical line G', we should have used the same amount of steam, practi- 
 cally, and have expanded down the line G' without the outlay of a single 
 pound of coal more than we are now using, while on the other side the 
 dotted theoretical line G would have cut off at B' and have gone down the 
 dotted line, utilizing the space bounded by H, I, G as efficient pressure on 
 the piston, instead of following the steam lines I and I'. This is serious, 
 
224 TWENTY YEARS WITH THE INDICATOR. 
 
 but we will shortly show by the figures what would be produced with a proper 
 arrangement of the valves. The line D is the vacuum line on one diagram, 
 and D' the vacuum line on the other. It will be noticed there is a peculiarity 
 with reference to the vacuum of this engine. We have only 6.2 pounds on 
 one end and 7 pounds on the other, or practically 12 J inches and 14 inches ; 
 the coarse dotted line, F, shows what we should have realized in obtaining a 
 vacuum of 12 pounds or 24 inches. These diagrams were taken on the night 
 of December 18, 1884, when the water was certainly cold enough to have pro- 
 duced a good vacuum, but the proportion of the machinery would not allow 
 it. Here, then, we have the difference between D' and F, which should have 
 given us 5 pounds more of mean pressure effectually, or of mean effectual 
 vacuum more- than we did receive. 
 
 These are the general features and facts with reference to the diagram. 
 The engine is well built, well proportioned, seemingly, and the boat is very 
 fast and economical. Now, suppose we could improve it in design or in 
 execution, what would be the effect ? In the high-pressure cylinder we have 
 in the respective ends 520.25 horse-power on the bottom, and 508.7 horse- 
 power on the top ; in the low-pressure cylinder, the actual diagram by the 
 indicator figures 389.24 horse-power on the bottom, and 332.55 horse-power 
 on the top. If the valves had worked, so that we could have obtained our 
 theoretical diagram by opening the valves sufficiently to feed the cylinder with 
 the pressure, cutting it off sharply so as to make the theoretical lines or close 
 approximation to them, and only have obtained the same vacuum which is 
 shown by the instrument, we would then have attained relatively 499.46 
 horse-power on the bottom and 402.72 horse-power on the top, making a very 
 radical gain. But if we could make this engine still more perfect in its work' 
 ing, so as to admit the steam, cut it off and then produce the vacuum of 12 
 pounds, we should have had a very different result indeed ; it would then 
 have been 683.15 horse-power' on the bottom and 616.29 horse-power on the 
 top, or to condense it, the actual diagrams combined show now 852 horse- 
 power on the top and 897 horse-power on the bottom. With proper increase, 
 it would give 1136 horse-power on the top and 1191 horse-power on the 
 bottom, or would make a still further difference of a very large amount in 
 proportion to the coal which the steamer burned, if these results were real- 
 ized. The receiver pressure is well taken care of by the low-pressure cylin- 
 der, but the whole amount of steam is not accounted for as between the high 
 and low-pressure above the atmospheric line, and the account below the 
 atmospheric line on the low-pressure cylinder should by some means be very 
 radically improved. It is quite possible that the ports and passages, and 
 probably the throw of the valves in this engine, are all based upon the olden- 
 time practice and would, upon careful investigation, be found to be too small 
 in area or too short in valve travel, and yet, as compared with previous prac- 
 tice, this steamer has a splendid record. The only question now is, how 
 much higher the record can be made by proper adjustments of the engine. 
 
TWENTY YEARS WITH THE INDICATOR. 225 
 
 LESSON LXXIV. 
 
 A COMPOUND NON-CONDENSING ENGINE. 
 
 Very frequently diagrams are put before an engineer to ask his general 
 opinion, and while there is no information of a positive sort to be gained 
 from this lesson, it is entirely within the province of the work to show some 
 things with which working engineers are frequently annoyed or expected to 
 do work with or against natural obstacles, in their way, which preclude 
 economy, regulation of speed, or any other practical result. Referring to 
 Fig. 152, we have the high-pressure side of a compound non-condensing 
 engine, scale 30. This is supposed to be governed by a throttle governor in 
 the pipe, which jumps up and down like a jack-in-the-box ; the different lines 
 here are precisely as the indicator left them. It will be seen that the initial 
 
 FIG. 152. 
 
 pressure of steam entering the cylinder in the highest instance is 38 + ; it 
 then varies to 27, and from that down to 18. Notice, that in two of the lines 
 an attempt is made to cut off, and in the other two lines, strange as it may 
 seem, initial pressure is below the maximum pressure by several pounds. 
 The back pressure amounts to between three and four pounds at the com- 
 mencement, and runs down to one and one-half pounds at the moment of 
 compression. 
 
 Fig. 153 represents the low-pressure side, running as high-pressure in 
 connection with 152. This arrangement was brought about by shifting a 
 valve between the cylinders, so as to allow direct steam to enter into both 
 ends and sides. The scale of 153 is ten. We have here 13 pounds initial, 
 but with an exceedingly great variation in the action of the steam, commenc- 
 ing with a back pressure of two pounds, running up to four, and dropping 
 back to three, showing that there is some peculiar action in the cylinder. 
 Fig. 153 was taken after 154. 
 
 Figs. A, B, 154 are from both ends of the compound cylinder, and were 
 taken at the same instant as 152, scale ten. We have an initial pressure in 
 
226 TWENTY YEARS WITH THE INDICATOR. 
 
 the A end of 7 pounds, which falls down to 1J pound by a most peculiar 
 line. It then runs along and gradually increases to 2 pounds, and a little 
 later to 3J. Whether this obstruction is caused by the peculiar passing of 
 the steam through the double-ported slide valve between the cylinders, or 
 whether it is caused by the motion of the exhaust valve, we have not deter- 
 mined, not being enabled to examine the inside or working parts of the en- 
 gine. The expansion in either case is most peculiar, and the terminal of this 
 double expansion line seems to be slightly below the atmospheric, but we 
 have the same general formation of the return or exhaust line which passes 
 above the line of direct pressure more than half a pound, falling back 
 again slightly and compressing above the induction pressure. The dia- 
 gram, taken altogether, is peculiar. It shows but an exceedingly 
 small amount of power exerted upon the piston as the back pressure 
 nearly neutralizes the forward pressure. Turning to the B end of the cyl- 
 inder, we have, if anything, a worse diagram than the A. The features, it will 
 be noticed, are very similar indeed in general, but there is a little difference 
 of outline. The extreme amount of initial pressure is only about five pounds ; 
 that barely continues for an inch of the stroke, when what we suppose to be 
 
 FIG. 153. 
 
 the expansion line, falls away similarly to that of the A end, resting on the at 
 mospheric line for an instant of time and dodging away again to a pressure of 
 nearly three pounds at the maximum on the second introduction of steam. In 
 the exhaust, for a very brief interval, the line returns on the atmospheric 
 pressure line, then rises very materially above the direct steam line continu- 
 ing two pounds above the atmospheric line with only five pounds of initial 
 pressure. It is usually supposed in compounding that some gain is to be 
 derived. In this case there is no economy, and what the gain can possibly be 
 by compounding a high-pressure engine with another high-pressure cylinder, 
 one side doing eight and one-half times as much power as the other, we can- 
 not imagine. The high-pressure side of this engine is doing from seven to 
 eight and one-half times the amount of power that the compound is doing. 
 We think the idea of high-pressure compounding is entirely a mistake, unless 
 some very different way of working it out shall be adopted from that shown 
 in this lesson. The movement of the governor was most erratic, and we have 
 no doubt, if the different parts of the engine were compared with a correctly 
 moving valve motion, that all the ports and steam passages would be found 
 
TWENTY YEARS WITH THE INDICATOR. 227 
 
 radically differing from good practice, and that the travel of the valves was 
 very ill-proportioned to the travel of the piston. They simply take their 
 place as curiosities, and for information to the working engineer, which, we 
 hope, very few of them will ever encounter, especially if they are compelled 
 
 FIG. 154. 
 
 to take charge of them. This engine is burning more than eight pounds of 
 fuel per horse-power per hour, if the data given of the amount of coal burned 
 is correct. The diagrams were taken to ascertain certain facts, by the writers 
 hands and indicator. 
 
 LESSON LXXV. 
 
 FISHKILL-LANDING CORLISS. 
 
 Fig. 155 was taken from a Corliss engine, built by the Fishkill Landing 
 Machine Company, 18 X 42 inches, running 63 revolutions, steam pressure 68 
 pounds, spring 30, heating a portion of the mill by exhaust steam. This dia- 
 gram was taken from an engine in its every-day work, without making any 
 changes, as the attachments were made at noon-time. The point was to get 
 at the average work of the engine, as well as the load upon it. Very little 
 need be said of it, other than that the valves of the engine seem to be in ad- 
 mirable condition for working, although, for best results, we would quicken 
 the action of the steam valve slightly so as to avoid the rounding corner be- 
 tween admission and steam lines, as well as to obtain nearer approximation to 
 boiler pressure, if possible. The demonstration on this diagram shows a very 
 close approximation to first-class practice. We would prefer a trifle earlier 
 release so as to obtain a little more compression, but, taken all in all, the dia- 
 gram gives a very excellent handling of the steam, and shows plainly that the 
 
228 
 
 TWENTY YEARS WITH THE INDICATOR, 
 
 valves are tight, and that the vibrations in pressure are taken account of by 
 the indicator. The approximation to boiler pressure is but in small measure 
 due to the late opening of the steam valve, (61 out of 68 pounds are 
 realized) but rather to the crooked steam pipe which has in it more 
 or less valves, and through which steam is drawn for dyeing as well. 
 
 If the reader should be at all skeptical as to the absolute necessity of 
 expressing the clearance on a diagram to obtain the result for which we make 
 the demonstration, let him add two per cent, to the length of the diagram 
 and then make the demonstration. Some engineers and others who have had 
 but little experience with the matter frequently attempt to show that no 
 
 FIG. 155. 
 
 demonstration is correct upon a diagram without adding the volume of 
 clearance, and whether it is guessed at or otherwise, it is necessary. The 
 volume of clearance added to this particular diagram will not vary the ex- 
 pansion line more than the width of it, and for the purposes for which we 
 make this demonstration will not allow the planimeter to discover any differ- 
 ence, but if we are figuring for the amount of water per horse-power, or 
 steam per horse-power, the clearance is necessary in order to insure the cor- 
 rectness, but if we are looking to show what a certain pressure at a certain 
 point will require cut-off at a certain point, to accomplish that base line the 
 clearance is no more necessary in a computation of this kind than is the read- 
 ing of a thermometer out-doors. 
 
TWENTY YEARS WITH THE INDICATOR. 229 
 
 LESSON LXXVI. 
 
 AN OCEAN STEAMSHIP COMPOUND ENGINE FITTED WITH CORLISS 
 
 VALVES. 
 
 Figs. 156 and 157 are from an ocean steamship, fitted with English en- 
 gines and English-built Corliss valves. If we refer first to 156, the solid line 
 diagram is precisely as the instrument left it. It is not a diagram that is 
 pleasing to the eye from its general appearance or proportion, nor indeed is 
 its mate when divested of the test of its efficiency. These were pronounced 
 by several chief engineers to be very rough-looking diagrams, and so the gen- 
 eral reader might term them ; but as we are dealing not in proportions, but 
 for information, we will apply the test and see. In the dotted diagram we 
 have taken the absolute pressure at A from the absolute vacuum line D, which 
 we find to be 54 pounds. Upon working the demonstration, as duly ex- 
 plained in previous lessons, we find that the realized pressure cut off at the 
 point C E, gives the actual pressure at A upon the proper expansion of the 
 steam. The theoretical line E, which is drawn dotted, shows plainly that the 
 same approximation exists in the correct working of steam, as is shown from 
 the time the steam valve gets open at the commencement of the diagram up 
 to the point where the amount of steam equals the cutting-off at the point C 
 E. The theoretical line in this case follows the actual expansion line for 
 quite a distance so closely as to avoid any cause for criticism. The departure 
 of the line of the instrument from the theoretical line shows plainly where the 
 valve commenced to open to allow the steam to exhaust. The release is 
 very good. We now come to a point in which there is a radical difference 
 between the valves and those of some engines which are shown in this 
 volume. 
 
 We find a receiver pressure at the commencement of exhaust of five 
 pounds, the maximum pressure is between seven and eight pounds, barely 
 reaching eight, while the terminal or commencement of compression is about 
 seven. There is a greater difference in the action of this engine witii refer- 
 ence to the receiver and the high-pressure cylinder in their relations to one 
 another, than in that of almost any other large marine engine diagram shown 
 in this volume. This steam line falls away but slightly, and we have an 
 initial pressure of plus 70 pounds, which falls to 68 at about one-fifth stroke, 
 and at the point of cut-off we have 62 pounds out of 70, showing that the 
 capacity of this valve to furnish steam at the maximum pressure or initial 
 pressure, is almost equal to fully one-half of the volume of the cylinder in 
 its steam supply, while in the slide-valve engines, as a rule, we find a 
 diminution of pressure varying all the way from 7 to 25 pounds from the 
 
230 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 initial, and in some cases exceeding even that. This might lead us to con- 
 sider whether the perfection of valve motions is increasing or decreasing, so 
 far as actual results go, upon the other marine engines of new construction. 
 
 It is a self-evident fact from 
 the diagrams, that while the 
 compounds may have ac- 
 complished certain results 
 with a less expenditure of 
 fuel than that which has 
 previously been accomplish- 
 ed, that there is still room 
 for a vast improvement in 
 the marine service, over that 
 of the old-fashioned beam, 
 or high and low-pressure 
 engines, and whether this 
 cannot be carried very much 
 further so as to compare 
 with the best stationary 
 practice, in spite of the dif- 
 ficulties which beset the 
 marine service, is not a 
 question upon which much 
 discussion can be had if the 
 economic factor is a pre- 
 dominant one. This dia- 
 gram, 156, so far shows the 
 highest economic efficiency 
 of any marine diagram we 
 have yet obtained. 
 
 If we now turn to Fig. 
 157, which is from the com- 
 pound cylinder, we have 
 charged against this cylin- 
 der the maximum pressure 
 in the receiver from the 
 high-pressure cylinder dia- 
 gram. It will be noticed 
 that there is quite a falling 
 off, and it is not the proper way, but in this case it has been deemed 
 preferable, so as to see what loss was incurred from a possible one, taking 
 the initial pressure as the maximum pressure of the high-pressure cylinder. 
 If we take the realized pressure in the compound cylinder, it, if anything, is 
 carried rather better as an approximation to a straight line than that in the 
 high-pressure cylinder, the reason for which is undoubtedly a larger valve 
 area. The demonstration in this diagram, taking A as the actual pressure 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 231 
 
 from the absolute vacuum, gives us 13J pounds, and, taking the initial press- 
 ure as stated, gives the cut-off at the point C and the theoretical line E. In 
 this case the approximation is exceedingly close, and the terminal theoretical 
 pressure varies slightly above the terminal of the expansion line, as it will do 
 whenever this basis is taken. If we are using a steam of lower tension than 
 
 we really charge in our com- 
 putation, its terminal press- 
 ure must be expected to be 
 somewhat above the terminal 
 of the theoretical line, for 
 volume and tension must both 
 be taken into account. The 
 release in this case is not 
 equal to that in the high- 
 pressure cylinder. The ex- 
 pansion according to the theo- 
 retical is 4J pounds below the 
 atmospheric line, while the ac- 
 tual line is precisely 4 pounds 
 below. The commencement 
 of the vacuum is between 
 eight and nine pounds, grad- 
 ually running down to be- 
 tween ten and eleven on one 
 end and eleven and twelve on 
 the other. The question may 
 readily occur as to this effect 
 in the economy of- the en- 
 gine ; in our own minds a 
 vacuum of twenty-four inches, 
 or twelve pounds, is prefer- 
 able to one of twenty-seven 
 or twenty-eight ; the question 
 has been often asked but 
 never answered, why should 
 we use fifteen or twenty men 
 at the mouth of the furnace 
 in throwing in coal, and a 
 donkey engine at the other 
 
 end of the engine doing its level best, to produce a temperature of from freez- 
 ing down towards zero on the alternate ends of the low-pressure cylinder, 
 calling for its equivalent in heat at every filling of the cylinder with steam ? 
 The probability is, the engineer who has charge of this ship has found that 
 he can run his feed-water a good many degrees hotter with a twenty-four 
 inch vacuum than with one which goes lower, and, we have no doubt, that in 
 that respect he is entirely correct. 
 
 FIG. 157. 
 
232 TWENTY YEARS WITH THE INDICATOR, 
 
 There is another thing which may be said of steam engine diagrams as 
 taken from marine engine cylinders. We have been allowed to examine a 
 great many steamships, and we have never yet seen proper or fully correct 
 appliances for taking of diagrams. Usually the side-pipes are connected at 
 the bottom of the cylinder, a round turn made and then connected on the 
 side near the top. A three-way cock is arranged above the grating and the 
 motion is taken from any convenient point. The clearance between the indi- 
 cator and the bottom of the cylinder we have measured where it has had 
 three times the distance to pass upon the bottom of the cylinder than on the 
 top, for the steam to pass from the engine into the piston of the indicator, 
 and for that reason we usually find the bottom of most marine engine dia- 
 grams latest, the corner most rounded, and it is not impossible that such is 
 the case with 156 and 157. While the diagrams show practically the amount 
 of power used, they show only an approximation to the actual in the valves, 
 and the further removed the indicator is from the piston, the less is the accurate 
 working condition of the valves shown or known. These two diagrams in 
 156 and 157 have a great many points of study for the practical engineer, 
 and they show at once an entire difference in the handling of the available 
 pressure, from that of most of the marine diagrams which are illustrated. 
 The full dimensions of the engine and the boiler pressure are not given ; 
 scale of the high-pressure diagram is 30, that of the low-pressure, 8. 
 
 LESSON LXXVII. 
 
 ANOTHER OCEAN STEAMSHIP COMPOUND ENGINE. 
 
 Quite a contrast in practice from the preceding lesson, and yet one of 
 the best engine results, will be found by a reference to Figs. 158 and 159, 
 which are from one of the recently built steamships with high and compound 
 cylinders, the high-pressure being 52 inches, compound cylinder 93 inches in 
 diameter, length of stroke five feet six inches, revolutions 62 per minute, 
 pressure in boiler 90 pounds, scale high-pressure forty, compound twelve, 
 vacuum gauge 25, hot well temperature 114. The high-pressure cylinder 
 has piston valves, the compound has slide valves. 
 
 Taking 158, our base line A shows that the cut-off occurred at the inter- 
 section of C D, D being the realized pressure, and C representing the volume 
 of the cylinder in its proportion to the length of stroke that the line D is to 
 the whole distance between the two extreme vertical lines. The theoretical 
 
TWENTY YEARS WITH THE INDICA TOR. 
 
 2 33 
 
 curve E shows that the loss from initial pressure to the point of cut-off is 13 
 pounds, total loss from boiler pressure at the point of cut-off 19 pounds plus. 
 The theoretical curve follows more closely than we would suppose after it 
 strikes the line, running but very slightly below it. This would probably be 
 accounted for by the fact that the steam is slightly superheated. The action 
 of the valves in this case was very nearly perfect, so far as being tight go ; 
 the release is early, and the counterpressure in the receiver commences at eleven 
 pounds, increases to plus thirteen, and at the point of commencement of 
 compression is between fourteen and fifteen pounds. The point at which 
 compression ceases and the steam valve commences to open, shows an almost 
 exactness of 43 pounds upon either end of the cylinder ; this is a point of 
 very material economy in a quick-acting engine like this, which is quick-acting 
 for so large an engine. The steam lines are carried very well, and the open- 
 
 f 
 
 FIG. 158. 
 
 ing of the valves is very nearly right in both cases. This is a desirable im- 
 provement over that of some of the steamships which still maintain 
 the old-fashioned slide valve, or even the old-fashioned piston valve 
 with slow speed in its whole length of travel. In this case, we have 
 no doubt the valves of the engine are not based upon the old-fashioned 
 idea of valve travel, and yet there could be a radical improvement if they 
 were speeded still higher in their proportion of travel to that of the piston 
 of the engine. Possibly a little increase of travel would aid it. 
 
 In diagram 159, we have again charged the engine with the full amount 
 of the maximum pressure in the receiver. One end has 13 pounds plus for its 
 initial, while the other end only gets 11 pounds, and it will be noticed that 
 the end upon which we have erected the demonstration, the main valve is con- 
 siderably later than on the other end. This, without any doubt, accounts for 
 
234 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 a portion of this change, and the contrast, as between the admission and 
 carrying of steain in the two diagrams, shows the most radical difference 
 between that of 158, the fact being 158 is piston and 159 slide valves. The 
 opening and closure of valves in 159 show plainly that they are very slow in 
 both motions, whether the passage ways are sufficient or not can only be told 
 by actual demonstration from measurement, but it is a self-evident fact from 
 the indicator, that the admission of steam on the left-hand diagram of 159 is 
 exceedingly slow. The valve is also slow in its motion, and the pressure 
 drops away much faster than on the other end of the same cylinder. This is 
 sometimes accomplished by having the valves so balanced for opening that 
 the real travel of the valve never reaches wide open on that end, while upon 
 the other end of the cylinder the valve, having been cast solid and finished, 
 had a travel which may be slightly earlier in its opening, and, owing to the 
 angularity of the rod, quicker in its movement. In this case the theoretical 
 
 FIG. 159. 
 
 curve follows closely, after the actual line of the instrument and the theoreti- 
 cal curve meet. In this case, our demonstration base A shows an actual 
 pressure at the very point of crossing the atmospheric line of 14.7 plus above 
 absolute vacuum. The line D represents the maximum receiver pressure, and 
 the working out of the two problems on the base line A gjves the point C on 
 D, from which the quantity of steam at the pressure of D should have been 
 cut off to furnish the pressure at A ; and in the computation for power or fuel 
 consumption, the amount of steam used between the valve's opening and 
 closing, was equivalent to the pressure cut off at C on D, so that while the 
 valve was not closed at C, its closing was equivalent to an increased pressure, 
 and a diminished volume of the cylinder filled at that pressure to accomplish 
 what was done at A. The release on both diagrams is very good, generally 
 considered, but the right-hand end diagram seems to have some kind of a 
 struggle going on which makes a curiously-shaped expansion line, or in the 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 235 
 
 closure of the valve evidently causes some vibration in the pressure which is 
 not fully accounted for. The solid-lined diagram commences with 9 pounds 
 of vacuum, runs down to plus 11 pounds, compresses on about 12 pounds, 
 and takes steam about the crossing of the atmospheric line. The other end 
 of the cylinder commences its vacuum at about 10 pounds, running down to 
 plus 12, as it could readily do from the less amount of steam used upon that 
 end of the cylinder. 
 
 The two diagrams, 158 and 159, were taken by a Thompson indicator in 
 order to ascertain the exact power, and as nearly as possible the position of 
 the valves. It would be very interesting if short connections, and a posi- 
 tively correct motion could be arranged for this pair of engines, to get at the 
 facts with reference to the actual position of the valves from a close connec- 
 tion to the cylinder, and the closest approximation to a positive and correct 
 motion for the instrument. 
 
 LESSON LXXVIII. 
 
 CONDENSING CARRIED BEYOND ITS ECONOMICAL APPLICATION. 
 
 In Fig. 160 we have an old Corliss engine, which has been running night 
 and day for a number of years, twenty- 
 two inches diameter, forty-eight inch 
 stroke, running 500 feet per minute 
 piston speed, independent condenser, 
 twenty-four spring. In this case the 
 amount of steam actually used by the 
 engine is represented by the line A, one 
 end of which touches the admission line, 
 and the other the dotted line, which is 
 the boundary of the proportion of the 
 cylinder filled with steam. The demon- 
 stration is made from the line of 
 
 FIG. ;60. 
 
236 TWENTY YEARS WITH THE INDICATOR. 
 
 pressure F. Apparently the engine cuts off very much shorter than where 
 the dotted line is drawn, but upon the demonstration we follow down the 
 dotted corners of where the ordinates cross the lines, forming the boundary 
 of the theoretical curve. At B we find that the line of the indicator or actual 
 is below the theoretical, at C the actual line is but very triflingly below. Now 
 what happens between A and B, or B and C I Nothing more or less than 
 that the valve does not close tight, or else that it leaks after having closed 
 and before it is firmly seated. From C to D the steam continues to come in ; 
 at E the expansion line is below the theoretical and it shows to the eye, com- 
 paratively, that the line drops. It is undoubtedly caused by the much more 
 rapid expansion of the steam. At F the lines are together, and so on, getting 
 a trifle above before the end of the stroke. There are several points about 
 this worthy of notice, the first, that the expansion line is somewhat irregular, 
 and the second is that the drifting which occurs from one point to the other 
 is fully proved by the location of the theoretical and the actual lines. The 
 vacuum, in this case, reaches nearly twelve pounds, or twenty-four inches ; 
 very many of our oldest engineers, who run condensing or compound, claim 
 that at this point it is by far the most economical, as the temperature of the 
 water at this particular point is much more advantageous for re-use or for 
 feeding than as though more vacuum was obtained. The high range of change 
 of temperature between even the terminal pressure of 3 or 5 pounds pressure 
 and 12 to 14 pounds of vacuum makes a tremendous waste of live steam by 
 condensation, and a moderate vacuum and hot feed water use less coal to 
 produce the same amount of indicated horse-power, other things being equal. 
 We believe this position is tenable ; however, it is a point for argument, and 
 engineers who wish to do so may find food for figures drawn from actual ex- 
 perience, in case they take it up, putting any experience they may have in 
 connection with the facts. 
 
 There is another point about this diagram which we have not elaborated 
 on, that is, the reference of the area between the high-pressure and condens- 
 ing, the relation of one to the other. The question is, does this engine do as 
 well as though it carried steam a little further at a less pressure or not ? 
 There is not the least doubt that in many cases engines are underloaded, and, 
 "to save coal," the condenser is added, and more coal used with a condenser 
 than without it ; the reason is not far to seek. A small quantity of steam 
 raises the heat but little, and it is easier to maintain 14 pounds vacuum on a 
 small amount of steam, and the cylinders are refrigerators to a greater extent 
 than the point of economy. 
 
TWENTY "YEARS WITH THE INDICATOR. 
 
 LESSON LXXIX. 
 
 AN OLD CORLISS ENGINE, ACTUAL COST OF A HORSE-POWER PER 
 
 HOUR. 
 
 In Fig. 161 we have a Corliss engine which has been running a number 
 
 of years, twenty inches diameter, 60-inch 
 
 stroke, sixty-three revolutions per minute, 
 fifty-five pounds boiler pressure, throttle 
 valve wide open, forty spring, Thompson 
 improved indicator, not quite the whole 
 amount of work on. Both ends are shown. 
 We have made a demonstration only upon 
 one end for the purpose of finding out how 
 the engine was running. These diagrams 
 were taken with a three-way cock, or by 
 changing from one end to the other. In 
 either case, we have demonstrated from the 
 diagram coming nearest the boiler pressure, 
 and it shows a beautiful working of steam, 
 A line of boiler pressure, B atmospheric 
 line, C vacuum, D volume of cylinder filled 
 with steam at boiler pressure to do the 
 work, cutting off at E, or at the intersection 
 of the lines A, D. The theoretical line is 
 dotted down to the point where it runs into 
 the actual line of the instrument, which is 
 considerable of a distance above the point 
 assumed for the base line. It then "follows 
 so closely that we have used our old method 
 again of dotting the intersection of the lines 
 in the demonstration. There may be a slight 
 difference in the terminal of this diagram, 
 for the original was very faintly drawn and 
 was traced over by hand. The steam line is 
 extremely good on the right-hand diagram ; 
 the one on the left falls off considerably, and 
 the pressure would seem to have changed 
 between the time of taking the two ends. 
 The vacuum in this case realizes about ten 
 
 FIG. 161. 
 
 pounds. The diagram was taken August 4, and we could hardly expect 
 much more than ten pounds, or twenty inches, at that time of year. 
 
238 TWENTY YEARS WITH THE INDICATOR. 
 
 Taken all in all, it is an excellent diagram. There is in this case no 
 leakage anywhere that we can find. The admission line, steam line, ex- 
 pansion, are all good. If we were to change anything it would be an 
 earlier release and a trifle more compression, and it is possible we might ob- 
 tain a little more vacuum by so doing. At the time of taking, a portion of 
 the machinery of this mill was stopped. There are some figures accompany- 
 ing this which will interest steam users. The power of the engine, f our times 
 per day, six days per week, averages 151-horse. The fuel used is three- 
 fourths anthracite coal dust from city coal yards, and one-fourth Clearfield 
 coal. The cost of this fuel is. as follows : Clearfield $3.30, and anthracite 
 dust $1.80 per ton of 2000 pounds, in the coal house ; sixty-six hours' use, 
 17,110 pounds of dust, 5,622 pounds of Clearfield, making 22,732 pounds, 
 costing $25.80 ; average power, 151-horse. The diagrams were taken twice 
 in the forenoon, twice in the afternoon, and the average of twenty-four cards 
 in the week taken for the amount of power. Pounds of coal per hour, 344 ; 
 pounds of coal per horse-power per hour, 2.28 ; cost of 151 horse-power per 
 hour, 00.39 ; cost of one horse-power one hour, .00259. Three horizontal, 
 tubular boilers are in use, 6 X 16 feet. 
 
 Two boilers are used in the summer, three in the winter. The fireman is 
 not allowed to use a slice bar any time during the day, but when the fires are 
 banked at night they are cleaned. The inside of the chimney is equal to the 
 full area of all the tubes in the three boilers, and 106 feet high, and the flue 
 from the boiler to the chimney is a little larger than the full area of the tubes 
 in the boiler. Ash-pit doors are never closed when the boilers are running. 
 The mills started nearly two years ago, and the grates are as straight as 
 when they were put into the- furnace. The agent is a close student of the 
 indicator, has profited by his experience, and bought a new Thompson Im- 
 proved for his engineer, and, on condition that we will not refer parties to 
 him, has given us permission to state the facts in connection, and also that his 
 engineers and firemen are well paid, and take just as much interest in the 
 economic handling of the engine and boilers as he does himself. We might, 
 perhaps, say that this engine was wanted in a hurry, and was second-hand 
 before it went into this mill, having been replaced by a very much larger one. 
 It was overhauled, and this is its record. 
 
 NOTE. The cost of an I. H. P., in anything but fractions of a cent per hour, should 
 not be allowed ; pounds of coal per I. H. P. per hour is a meaningless and indefinite 
 term. 
 
TWENTY YEARS, WITH THE INDICATOR. 
 
 LESSON LXXX. 
 
 WHAT AN OVERLOADED CORLISS ENGINE CAN DO SOME OF THE 
 GENERAL DEFECTS OF ARRANGEMENT, 
 
 The diagrams with this are from a Watts, Campbell & Co. Corliss engine, 
 and we have laid aside anything that is theoretical or supposed, taking only 
 visible facts. And this shows one of the instances which are constantly 
 coming to the notice of the engineer who has any indicating to do, of the ne- 
 cessity of simultaneous diagrams for adjustment of valves, or for reliable data 
 with reference to power exerted. 
 
 ^ -/:- 
 
 FIG. 162. 
 
 The diagrams in this case were taken on each end of the cylinder ; A is 
 the line of boiler pressure at the instant the diagram was taken, the scale 
 being forty. B, B' represent the visible point of cut-off, simply for com- 
 parison. C, C' are the respective lines of initial pressure above the atmos- 
 pheric line, or the instrument at rest. D, D' show the lowest pressure from 
 initial realized, and E shows what went on occasionally while one end was 
 trying to catch up with or do as much as the other. These lines, simple in 
 themselves, are full of meaning and will bear a little investigation. 
 
 The engine at this time was in the course of adjustment for the position 
 of the valves to obtain the best possible results. The diagrams H and C were 
 taken on the very same strokes of the engine, but we have not drawn in all 
 the fluctuations caused by the reaching of the governor, first to increase for 
 one end and then to diminish the cut-off cams' action for the other. We have 
 here a boiler pressure of eighty-two pounds, a realized pressure of sixty-four 
 pounds, a supply pipe of 2 J or 3 inches diameter for a cylinder of 14 X 32 
 
2io TWENTY YEARS WITH THE INDICATOR, 
 
 inches running 80 to 88 revolutions. The H end diagram in this case meas- 
 ures 391 on the planimeter, the C end measures 328. The line E occurred 
 on every single diagram that was taken until after the two ends were bal- 
 anced. In this case 391 equals 79.5 horse-power, 328 equals 67.6 horse- 
 power, so that on a load of 80 horse-power we have a variation of about 
 twelve horse-power between the H and C ends on the same stroke, or almost 
 sixteen per cent. It will be noticed that the terminal pressure of the head 
 end is seventeen pounds, the terminal pressure of the crank end is thirteen 
 pounds, while the terminal pressure of the crank end when it makes a jump, 
 as in the case of the diagram E, is 33^ pounds. The loss in the first place 
 eighteen pounds between boiler pressure and the highest realized pressure on 
 the head end. A loss is also made from the moment the valves open until 
 they cut-off of ten pounds more on the head end, between realized initial and 
 the pressure at cutting off, making twenty-eight pounds below boiler press- 
 ure, or a little over one-third of the steam pressure to start with on the ex- 
 pansion line. On the crank end a loss of twenty pounds between boiler and 
 highest initial and eight pounds between highest initial and at point of cut- 
 off. By a curious coincidence both ends cut off at about the same loss of 
 pressure although at different lengths. The crank end carries steam equiv- 
 alent to about 13 J, as compared with the head end carrying 18, call it inches 
 only for comparison. Most of these diagrams show the racing of the gover- 
 nor up and down with every stroke of the engine, endeavoring in every in- 
 stance after the valve had been set for the head to get around quick enough 
 to set the valve for the crank ; in this case very wide variations were the 
 consequence, and, in the particular diagram which we have engraved, only 
 three lines were made in order to catch carrying steam at three-quarters 
 stroke. Wherever more than four or five strokes of the engine were made 
 upon the indicator card we find this carrying nearly full stroke on every one, 
 so that about one line in four, or five, the regulator jumped to catch the crank 
 end with the head end. Good engineers will understand this at once. The 
 changing of the governor is continual and about once in so many strokes it 
 will set a little further than is necessary and skip tripping the valve. All en- 
 gineers will also see that this is an exceedingly dangerous practice ; there is a 
 great deal of force exerted as between 60 and 100 horse-power, when it is only 
 for a single stroke of the engine, and something has to withstand that power 
 or else the engine would smash. 
 
 There is another peculiarity in this case ; it will be noticed that the crank 
 valve is very nearly in position so far as the admission line is concerned, while 
 the head valve shows plainly where the cushion terminates and the admission 
 line commences ; also that the admission line leans away to the right from the 
 vertical line. This engine had only one screw in the jim-crank of the main 
 steam valves, and the thread which connected the crab-claw with the iron stem 
 was so coarse that a whole turn was too much, and nothing less than a whole 
 turn could be given in adjustment, which is not the case with larger size 
 engines. The eccentric having been put right for three valves, and the same 
 difficulty existing on the crank valve, we were compelled to leave it a little 
 
TWENTY YEARS WITH THE INDICATOR. 241 
 
 late oil the admission line ; for had we changed it again on the main rod, it 
 would have thrown the crank valve just as much forward or backward, leaving 
 us with only a whole turn to adjust with. This practice of having right and 
 left threads on both ends of the exhaust and steam valve connections, to give 
 nicety of adjustment should be insisted on by engineers in new engines. 
 
 If the readers will figure the pounds exerted between 79.5 horse-power 
 on one end and 67.6 on the other, they will find that there is a very great 
 change of force exerted between the different strokes and as many strokes as 
 are made in each minute, which is not at all to the benefit of the engine. 
 There are very many other points connected with these simultaneous dia- 
 grams, but leaving all but the practical, we find enough to encounter to draw 
 our attention to the fact that it is very necessary to use both indicators, if we 
 are getting either the power correctly, the variations in power or the position 
 of the valves. It is an interesting study and more interesting in the practice. 
 It will be noticed on the crank end that the exhaust is a little late on the 
 small diagram, and that the same feature is very evident in the larger one. 
 The small amount of power exhausts under a start of about five pounds, while 
 the jump to nearly whole stroke exhausts under twenty- two or twenty-three 
 pounds back pressure at the beginning of the return stroke. There are sev- 
 eral interesting features which will be borne out if a little examination is 
 given, and will prove all the more interesting. 
 
 This is one of the troublesome things to engineers, running from 50 to 
 100 H. P. regularly on a 60 H. P. machine. Some of the full load diagrams 
 on this engine show 102 H. P., the builders did not apply the small feed- 
 pipe, or arrange the engine to carry full stroke. 
 
 LESSON LXXXI. 
 
 AN OCEAN COMPOUND. 
 
 Figs. 163 and 164 were taken nearly three years since, from a then new 
 ocean steamer ; 163 is scale 32 per inch ; 164, 12 per inch. The difference 
 which is shown between the different ends of the cylinder show a trifle less 
 than 300 horse-power difference between the left and the right-hand card. 
 Taking A and A' as the base lines, we find the point of cut-off at B, B', from 
 each of which points the theoretical line is drawn, taking the cylinder as realiz- 
 ing boiler pressure. The expansion line upon one end is somewhat peculiar, 
 
242 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 but closely follows the theoretical with a little difference, which will be ac- 
 counted for, as between realized and boiler pressure. Upon the other end 
 we have a different account ; the steam enters the cylinder and immediately 
 falls away in pressure, so that at B' ten pounds of pressure is lost between 
 the initial and the point of cut-off, allowing six pounds for lost boiler pressure 
 
 equivalent to equal to the 
 other end. There is a 
 reason for this. The left- 
 hand card is from the top 
 of the cylinder where the 
 distance from the steam 
 way to the indicator cock 
 is less than one foot, while 
 the other end is taken 
 from the bottom of the 
 cylinder through a steam 
 pipe more than five feet 
 long. It is probable that 
 the left-hand diagram is 
 much nearer the fact than 
 the right-hand one, and 
 that quite a difference in 
 the horse-power would be 
 developed if both these 
 connections were made 
 short, and two indicators, 
 instead of one, were used. 
 The release of this engine 
 is very good. We find 
 the commencement of ex- 
 haust on one end with 7 
 pounds receiver pressure, 
 and only a trifle more 
 than 7 on the other; the 
 maximum pressure is 12 
 pounds. Quite a varia- 
 tion occurs in compres- 
 
 FIG. 163. 
 
 sion, and if the difference 
 exists in proportion to the 
 
 length of pipe connection that is shown in the compression on the two 
 diagrams, then the left-hand diagram has a square steam corner, and the 
 right-hand one comes honestly by the little hump at the commencement of 
 the steam line. All these diagrams for that matter are only approximately 
 correct, on account of this very crude way of establishing the indicator 
 connections between the top and bottom. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 243 
 
 line then falls off from re- 
 pressure almost 8 pounds. 
 
 Turning to Fig. 164, we have a most peculiar train of circumstances. 
 These diagrams were taken with a 12 scale. We have only drawn the theo- 
 retical curve upon one end, as that answers every purpose for comparison of 
 the diagram. We first charge the engine with the full amount of receiver 
 
 pressure, viz., 12 pounds; it will be 
 seen that the opening of the valve is 
 such that a little kick occurs in the 
 opening action of the indicator. The 
 steam 
 ceiver 
 
 We have drawn the line D where the 
 two steam lines of the diagram cross 
 each other, and we find there a loss 
 of plus 7 on one and about 8 pounds 
 on the other end. But, to give the 
 engine credit, we have drawn the 
 line B on one side and B' on the 
 other as about the average of the 
 realized pressure initial, and what 
 the engine should have done if 
 either end of the compound cylinder 
 had have worked as well as the left- 
 hand of the high-pressure. The line 
 F is the line of the instrument, B is 
 the line of initial pressure, C equals 
 the volume of the cylinder filled or 
 the point ol cut-off, E the theoretical 
 line drawn from the base line A. The 
 steam in the cylinder if it had fol- 
 lowed the line B up to the point C, 
 and then the theoretical line would 
 have yielded almost 200 horse-power 
 more than it does do ; the actual 
 amount of the card shown is 1474.8 
 horse-power, while had it have real- 
 ized the pressure B to the point 
 C and the expansion line, with the 
 same vacuum, it would have yielded 
 1662.9 horse-power. We find that 
 neither end of the compound cylinder accomplished as much work as 
 the high-pressure, and that there is a more radical difference in the actually 
 developed power in the high-pressure cylinder, than in the low. The results 
 in this case may be of interest to our readers. The steamship, from whose 
 engines these diagrams were taken, made three round trips, (he engines were 
 very largely altered and very much improved, as they would need to be from 
 the apparent action shown, from the very great differences which exist 
 
 FIG. 164. 
 
244 TWENTY YEARS WITH THE INDICATOR. 
 
 in both high and low-pressure cylinder, from first-class practices. These 
 things are not visionary, theoretical, or supposable ; it is only a matter 
 of fact that they do exist as they do, and that it is so expensive a matter when 
 such results as these are carefully figured out, to make a change in an engine, 
 or abolish them entirely. 
 
 LESSON LXXXH. 
 
 DEFECTIVE CONSTRUCTION, AND AN INCIDENT IN THE USE OF THE 
 
 PANTOGRAPH. 
 
 This lesson, with the exception of the Harris-Corliss diagram, shows 
 radical defects in construction, in usage and in the application of the indi- 
 cator, and it is quite as necessary that the readers of this volume should 
 know where to look for difficulties and how to avoid them, as it is to know 
 the theory of doing a thing right without having the practical results before 
 them. 
 
 Figs. 165 and 166 were both taken from the same engine. The engine 
 was of peculiar construction, and had been subject to several examinations 
 and alterations, the warranty being, as is frequently the case, that it should 
 equal the Corliss engine in economy, development and regulation. As the 
 readers of this volume will have plenty of Corliss material with which to com- 
 pare, they must form their own inferences or deductions, we have only to nar- 
 rate the facts. The engine in question was built for a speed of 80 revolutions 
 per minute ; it was well located, well connected, but for some reason it had 
 not given satisfaction to its owners. 
 
 Fig. 165 is an actual diagram with the simple addition of absolute 
 vacuum, the base line and the theoretical curve, with a portion of the 
 initial or realized pressure line added, in order to show that after the valve 
 commenced to open, the pressure in the cylinder considerably increased, and 
 instantly commenced to decrease perceptibly before the point of cut-off, which 
 we have termed visible, occurred. The expansion line would seem to show 
 a very fair action both of the indicator and steam, and without the theoreti- 
 cal curve, (with the exception of the joining of the admission and steam lines, 
 and the little irregularities in that line as well as in the compression) it 
 would seem to be a pretty good diagram. But when we apply the base line, 
 to learn from it the point of cut-off and that one point of the theoretical 
 curve quite corroborates the other with regard to the amount of steam used, 
 it becomes less pleasant than on its first impression. 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 245 
 
 Fig. 165 was taken at a speed of 80 revolutions ; the peculiarities of the 
 diagram will be explained later. Fig. 166 was taken from the same engine 
 during the same trial or observation, and at a moment when the speed of the 
 engine had reached 124 revolutions per minute. The peculiarities in this are 
 that the same general features which occurred in 165 are present, both in the 
 compression and steam lines, and that the serrations or irregularity of the 
 steam line is increased very much more by the high speed than it is by the 
 usual speed of the engine. It will be seen also that the point of cut-off is 
 quite different from that of the previous diagram, or 165, but that there still 
 remains this extreme leak, and that both points on the theoretical line, initial 
 and terminal pressure, corroborate the previous reading. Fig. 165 figures by 
 the planimeter 10.1 horse-power; Fig. 166 figures 10.2 horse-power., at the 
 different speeds at which they were running, at the moment of taking. It will 
 
 be noticed that the steam line in both 
 these diagrams shows almost a parallel 
 line with the vertical at that end. This 
 engine had been carefully examined by an 
 old engineer, who had indicated it and 
 reported upon it ; the report was very 
 favorable indeed. The facts in the case 
 are as follows : The two diagrams, 165 
 and 166, show a variation of revolutions, 
 44, per minute ; during the time of the 
 
 FIG. 165. 
 
 trial, the engine ran from 68 to 124, and there was connected with it 
 an attachment for showing the variation in speed, which during the time 
 ran completely off the paper band, without making the least mark; so 
 much for the facts with reference to the regulation. During the time 
 of trial, which extended over some thirteen hours, we applied the theo- 
 retical curve, and were somewhat surprised. When the finish of the test was 
 made, the manager was called upon to make some examinations (which had 
 been quietly made the night before, but without any proof). His attention 
 was called to the fact that the piston traveled over the indicator plug holes 
 at both ends of the cylinder, so that, as a matter of fact, the diagrams 
 were perfectly worthless in regard to their steam lines and admission lines ; 
 the expansion line is, however, fully corroborated by admitting steam to the 
 chest while the valves were unhooked from the eccentric, and such a jet of 
 steam as came through the indicator plug holes has only been seen by those 
 who have found valves which leak badly. In the case of 165, the steam line 
 
246 TWENTY YEARS WITH THE INDICATOR. 
 
 approximates closely to a parallel line, but when the piston moves back so 
 that the indicator hole is uncovered, the steam is admitted more and more 
 into the indicator, giving a triflingly higher pressure just as the movement for 
 the cut-off begins to take effect. The compression plainly shows that some- 
 thing goes on beyond it, and whatever amount of space may lie beyond that 
 covered by the indicator hole we know nothing of, for no changes could be 
 made, or we would promptly have made a clearance with a cold chisel or 
 drill. 
 
 Fig. 166 shows the admission while the engine was racing, and simply 
 magnifies what is plainly seen in 165 in a smaller degree. The expansion 
 line in both cases, without the theoretical, would give an idea of a good line. 
 
 FIG. 166. 
 
 But, taking the actual pressure at the base line of the demonstration, we find 
 there is entirely too much pressure for the steam and volume cut-off as by 
 the visible point of cut-off on the diagram. We also find a corroboration of 
 this in the fact that the theoretical line runs below the actual line, and 
 the terminal pressure is as much too high in proportion as the absolute 
 pressure is at the point of the base line. We were told some months after 
 that the price of this engine had more than been paid by the damage it had 
 done to the place it was working in, which would seem to corroborate the 
 indicator's work to the extent of wasting the steam, and also the fact that 
 the regulation was exceedingly far from that of the average-built Corliss 
 steam engine. These two diagrams, 165 and 166, are well worthy the careful 
 study of every engineer who desires to know something further as to the 
 reliability of the indicator. Both diagrams were taken with a 30 scale. 
 
TWENTY YEARS WITH THE INDICATOR. 247 
 
 AN INCIDENT. 
 
 Fig. 167 is from a Harris-Corliss engine slightly thrcitled, scale 40, and 
 the only remarkable feature about this is the peculiar twist in the expansion 
 line, something which very rarely occurs. This occurred a number of 
 times while the author was busy in changing the valves, eccentrics, cranks, 
 etc., and was really quite a puzzle until particular attention was given to 
 what made it. The result of an examination proved that the cord which led 
 from the indicator to the pantograph motion, which was being used, struck 
 apon the top of the slotted screw next to the post to which our strings were 
 attached, in such a way that a snap was given to the cord both ways, sud- 
 denly changing the speed of the paper barrel first above and then below, 
 until this slot-headed screw, in the forward and backward movements of 
 the cross-head, passed out of reach or control of the line of string. The 
 pantograph was dropped a quarter of an 
 inch on the post, and as much in the cross- 
 head, and a long attempt was then made to 
 
 repeat it, but it was no use. Both indi- / I 
 
 cators were taken off and carefully ex- / 
 
 amined. Nothing was found out. The / 
 
 pantograph was again raised to its original , ^ ^S 
 
 position, and the matter was repeated. 
 
 FIG. 167. 
 
 with variations, to satisfy us that this kind of an expansion line can 
 be produced by snapping the indicator string by the movement of a 
 nail, peg, or any other obstruction, across the line of the string. This same 
 matter comes up wherever the pendulum is applied to any engine for the 
 purpose of taking an indicator diagram. In this particular case the speed 
 of the paper barrel was generally changed, first fast and then slow. The 
 same thing occurs, although it is seen in a different way, and will be treated 
 of hereafter, whenever the pendulum motion is being used, unless the 
 sliding bar is used to communicate the motion to the indicator barrel. When- 
 ever the pendulum is so attached that the motion is coincident with that of 
 the piston, and is also exactly equal both sides of the center, very little varia- 
 tion will appear ; but whenever the swing of the peg, or even an arc of a 
 circle is used to communicate motion, the distance traveled is unequal dis- 
 tances on a straight line, while the speed of the motion may be uniform ; the 
 travel being upon an arc of a circle, it will give an unequal distance when 
 applied to the travel upon the slides by the cross-head, and this varies the 
 speed of the indicator barrel ; and while it may be small in amount, it is suf- 
 
248 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 ficient to make the expansion line entirely unreliable. This same point can 
 be accomplished by boring a hole and putting a little peg, which has been 
 slightly slotted on the top, with partly rounded sides, into the peg arm of 
 the pantograph ; but if the experiment is tried, be careful that this peg no 
 more than strikes about one-third or one-half the diameter of the indicator 
 cord, or a paper barrel spring completely smashed may be the result. This 
 is an extremely insignificant point in some respects, it is the key to any mo- 
 tion that varies, or attempts to make straight travel by passing through an 
 arc of a circle. 
 
 A CURIOSITY. 
 
 Fig. 168 is another experiment in steam engine building, scale 30. This 
 was an engine used in grinding rubber. The cylinder was built with Corliss 
 
 valves, while a different style regulator 
 had been attached to an old bed, or 
 the girder part of the bed. The several 
 diagrams are only a small portion of 
 the erratic movements caused by the 
 changes in the regulator. The changes 
 in the load were considerable, and the 
 regulator would sometimes change from 
 its highest to its lowest point on the 
 very same stroke. Very little more can 
 be said about this figure than that it 
 shows a regulator utterly unfit to be 
 used where any change of load should 
 occur, and shows also that there is an 
 exceedingly good opportunity for the 
 engine to smash itself, in case of a 
 sudden change from one load to the 
 other, that was from the heaviest load 
 to the lightest. On the other hand, if 
 it was suddenly from light to heavy 
 the engine would be exceedingly apt 
 to stop. A, A, indicate the extreme 
 ends of the atmospheric line of the 
 instrument, and, in order to show the 
 differences between the exhaust lines 
 of the different diagrams, the atmos- 
 
 ^ ' .{ pheric line is omitted. B, C and D 
 
 show variations, the card intending to 
 '' ''// cover ten strokes of the engine, speed 
 s 1 , 80 per minute. It shows also that the 
 
 ^ / / Ft 
 
 ^^~^' ''^''/ \ engine is entirely insufficient in its port 
 
 ^--j- ^ '_ > \ ways to exhaust under carrying steam 
 
 FIG. 168. two-thirds of the stroke. It shows in 
 
 / 
 / 
 i 
 
 i 
 i 
 
 *>/ 
 
 <! 
 
 T 
 
 \ 
 
 / 
 
 % 
 
 1 
 
 \ 1 
 
 
 \ 
 
 
 \ 
 
 i 
 
 \ 
 
 / 
 
 \ 
 
 / 
 
 I 11 
 
 / 
 
 11 
 
 
 1 1 
 
 
 | || 
 
 
 l] 
 
 
 I/I 
 
 
 I 
 
 
 /i 
 
 1 
 
 / 
 
 1 
 
 / ! 
 
 ! 
 
 / 1 
 
 i 
 
 / 1 
 
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 I 
 
 i 
 
 \ 
 
 , 
 
 . 
 
 i 
 
 \ 
 
 ; 
 
 I, 
 
 
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 1 
 
 
 u 
 
TWENTY YEAES WITH THE INDICATOR. 249 
 
 every case that the valves are a trifle late in their action, and the steam 
 lines do not approximate very closely to a Corliss engine built by any of the 
 builders who understand their business. In this case we have a pretty 
 good cylinder with a very poor regulator, and an exceedingly poor show- 
 ing of a Corliss engine for regulation, but it is a Corliss engine only 
 in name, like many others, the improvements upon it. make it practically 
 worthless, or a departure from the real Corliss engine principles makes 
 a departure from good practice and also from good results. These four 
 diagrams cover an amount of information which will only be measured 
 by the patience that the persevering reader shall give to them, and the 
 benefits which he will derive will only be measured by his acuteness and 
 careful attention, and if these are given many engineers will be saved trouble 
 or being humbugged by any attempt by parties who are interested in the 
 sale or attempted misrepresentation of the actual working of machines. 
 Excepting 167, these should all find their way to the scrap-pile, and cease to 
 be an annoyance to the engineer in charge, as well as to the men who supply 
 steam and fuel for their running. 
 
 LESSON LXXXIII. 
 
 FOR THE BEGINNERS. 
 
 During the four years which have elapsed since the first systematic 
 course of articles upon the indicator first appeared, the author has found 
 very frequent inquiries for the elements, as men were continually taking up 
 the indicator to learn something of it, who had not seen the first series of 
 articles, and consequently had omitted many little points which are essential 
 to men who have never held or handled the indicator ; to such ones this les- 
 son is especially adapted, while it will not do the older ones any harm to oc- 
 casionally run over it in order to obtain other or more information and fre- 
 quent reference to something about which they may have doubts. The indi- 
 cator is intended not only to measure correctly the proper power exerted, but 
 it also gives us, if correctly applied, the manner in which the valves handle 
 the steam ; it tells us of the position of the valves with regard to the stroke, 
 whether the motion of the valves is sufficient or not. It also tells us whether 
 the ports, passages, throttle valves, steam pipes, exhaust pipes and ways are 
 all sufficient, or, if insufficient. It is not able to tell the particular point at 
 which the trouble is, but it will give the trouble, and then we must find 
 
250 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 its exact location. It frequently shows us that feed-water heaters are an 
 element of trouble by the insufficiency of the area of the steain passage 
 allowed for the exhaust steam. Sometimes it will tell us of a leak in 
 valves, or of many little points which are not necessarily to be particular- 
 ized here, so that to cut the enumeration of all these things short, the 
 indicator will tell us at any time, if honestly applied, when the engine is 
 working correctly or incorrectly ; if incorrectly, it will show T whether there is 
 back pressure, too late release, too tardy admission, throttling between 
 admission and expansion, whether the engine is overloaded, or any of these 
 numerous happenings which can be found in item and detail by the previous 
 lessons in this book. Directions have already been given for computing ; any 
 one can do this, who chooses to give a little time to it. 
 
 Now the standard in all cases is the ideal or perfect diagram. The 
 perfect steam engine (which has not yet been built) is expected to economize 
 
 G \ 
 
 ^ 
 
 FIG. 169. 
 
 by the use of full boiler pressure, to cut it off sharply, expand it theoreti- 
 cally, release it early, exhaust, if non-condensing, at the atmospheric line, and 
 if a condensing engine, we are expected to accomplish about 14 pounds of 
 vacuum (theoretically 14.7 at the level of the sea) to compress slightly 
 according to the fancy of the builder or the engineer, and in this way to 
 realize all the heat units and the effective pressure upon the piston, and in 
 that way make the coal consumption reduced to the minimum. The steam 
 engine cannot, however, go back to the steam boiler and rearrange inefficient 
 furnaces, too large or too small steam space, or any of the thousand things 
 which may go towards making an incomplete, insufficient, or badly arranged 
 boiler plant. The engine is expected to take the steam pressure in the pipe 
 and use it in the most economical way ; for that reason, we have constructed 
 in Fig. 169 the generally-accepted theoretical diagram. It is made upon a 
 
TWENTY YEARS WITH THE INDICATOR. 251 
 
 /scale of 30 to the inch, having 60 pounds steam pressure and 14.7 pounds or 
 absolute vacuum. The various lines to which frequent references have been 
 made in this book, are as follows : A is the absolute vacuum, which differs 
 with the barometric reading, and we have laid out the vacuum for the level of 
 the sea ; B is the atmospheric line of the instrument or the line at which the 
 pencil point of the indicator rests after having been thoroughly heated, after 
 allowing the steam to come in contact with the piston and working parts of 
 the instrument, and then shut off all steam connections. And here it is well 
 to take notice of a little point which may have been omitted ; when the indi- 
 cator has been attached, the motion arranged and the cord or wire connected, 
 turn the steam gently upon the spring, heat the instrument thoroughly, and 
 not until this has been done, should the atmospheric line be taken ; having 
 done this, now be extremely careful never to allow -a particle of steam to 
 escape from the three-way cock while taking the atmospheric line, for if you do, 
 you will distort the line, making it too high or too low ; D represents the 
 boiler pressure, and is dotted from the point of cut-off E, I, the rest of the 
 length of the diagram ; E represents what is usually spoken of as the steam 
 line, or that portion of the diagram made between the time the valve is 
 opened and that portion of the piston travel that the valve is held open ; the 
 dotted ordinate, I, dropped from E shows the point at which the cut-off valve 
 is supposed to have positively closed, and C represents the expansion line from 
 the point of cut-off E I to the point of release G'. We will digress for a mo- 
 ment. Such a steam line as we have drawn in Fig. 169, E, will not be found 
 one time in thousands, the reason for it is assignable to a great variety of 
 causes, which may be changed materially by either of the following ; by inat- 
 tention to the correctness of the reducing motion, and insufficient steam ports, 
 steam passages or steam pipes, or too small a throttle valve, to an ill-propor- 
 tioned travel of the valve with reference to the piston ; wherever any of these 
 reasons operate, this line will be modified in any of a. great many ways which 
 are shown in the preceding lessons, as well as in Figs. 170, 171. The expan- 
 sion line C partakes of a great many variations. It is exceedingly rare that 
 we find one that approximates very closely, and for this there are a great many 
 different reasons ; the distortion of the motion, any error in the travel or 
 capacity of the valves, any leak in the valves, which may be very trifling, will 
 make a difference in this line. Leaking by the piston, the presence of water, 
 to which is added the variable speed of the piston, or expansion, diminution 
 of pressure, increase in volume, a change in the physical properties of the 
 steam, and if the indicator itself be not in perfect working order, the expan- 
 sion line is likely to be an erratic one. The theory upon which the expansion 
 line is based is that of Mariotte's law, that increasing the volume diminishes 
 the pressure in a certain known ratio. This from the very nature of the 
 thing, has never been definitely proved, but the general foundation of the 
 law is that as the volume doubles the pressure decreases one-half, and so in 
 proportion. At G' the continuation of the dotted, like the expansion line C, 
 has been drawn at an angle rather sharper, perhaps, than the general con- 
 struction of engines will admit of in release, by the actual lines of the indi- 
 
252 TWENTY YEARS WITH THE INDICATOR. 
 
 cator, but we have drawn it thus distinct, for the working engineer has fre- 
 quently an idea that he should not release until he had obtained everything 
 that was possible out of the steam. Here is a point of practice about 
 which some engineers now differ, but those with the largest machinery and 
 the broadest practice, have no doubt and no difference, viz., if we commence 
 our release at G', following the line which shows a rounding into the con- 
 denser at the extreme end of the stroke by a full open valve, we shall then 
 continue the line G below the atmospheric line, so that it reaches the full 
 extent of the vacuum at about one-tenth of the stroke ; and if the exhaust 
 valve of an engine taking the Corliss as standard, or any other well-con- 
 structed engine opens a little before the end of the stroke in order to 
 release the expanded steam as soon as possible, and allow the condenser to 
 have full swing at it, we shall close that valve as much before the end of the 
 stroke on its exhaust as we open it before the end of the stroke, provided the 
 builder of the engine has properly proportioned the travel of the valve. As 
 we are working on an ideal card, we shall suppose we are dealing with a first- 
 
 B~ 
 
 FIG. 170. 
 
 class builder so that the distance from G' to the end of the stroke, will give 
 the condenser a wide open valve at the very commencement of the return 
 stroke, and will immediately reduce the steam to full vacuum at the intersec- 
 tion of the lines G A from the terminal pressure end of the diagram, and will 
 make the dotted compression line G, touching the vertical line J at about 17 
 pounds above atmospheric pressure. There is a great difference of opinion 
 among engineers, some claiming that it is impossible to compress upon a con- 
 densing engine. This is a mistaken idea, and, while many prefer to run 
 their engines without any compression, they will find, if the engine is prop- 
 erly constructed, that compression within a reasonable limit is invariably an 
 advantage, because, if we take the line G as an instance, we have 17 pounds 
 above the atmospheric line of pressure at the very end of the stroke ; if, 
 now, the steam valve is properly set, so that it commences to open and 
 continues the dotted line G, from its intersection with J, following up the 
 line J, by what is known as the admission line, we shall then have 17 
 pounds pressure in that end of the cylinder upon which we put enough 
 
TWENTY YEARS WITH THE INDICATOR. 253 
 
 to bring it up to 60 pounds, while, if we do not have any compression, 
 we have to put 60 pounds instead of 43. We have now completed 
 the circuit of the diagram ; upon the same diagram, 169, notice the 
 irregularly dotted line H (which is the most usual line of compression) in 
 which the steam is carried beyond the point G', by means of the dotted 
 line H, which is differently dotted from G', and where the steam pressure 
 is confined until almost the extreme range of travel of the piston, 
 barely commencing to open at the very end of the stroke, in which case the 
 irregular line H is continued and shows the effect of a later opening, so 
 that the absolute vacuum is not obtained until the piston has traveled 
 twice as far on its return stroke, or about one-fifth of the whole stroke, as it 
 did with the earlier release at G'. As the motion of the valve here is later, 
 so it will be later in closing. The line H is supposed then, from the point 
 of its intersection with A, to travel from the line A until it reaches H, where 
 it will be found to extend but little above the atmospheric line, making only 
 a pressure of eight pounds. The general practice on condensing engines is 
 that wherever the late opening and late closure are practiced, that it is much 
 more frequently followed with 7, 8, 9, or 10 pounds of vacuum instead of 
 14.7. The earlier the release consistent with proper compression, the larger 
 amount of vacuum is obtained from the same amount of steam. The later 
 the release, the later the compression, and the less amount of vacuum is gen- 
 erally obtained, but as all classes have their ideas, and we take diagrams from 
 all descriptions of adjustments, we have thought best to introduce here for 
 the beginner's benefit, the long dash and dotted line F, which shows a very 
 general idea of excessive steam lead, joined to a considerable compression. 
 This line may be made either by excessive compression or by a steam lead ; 
 and by steam lead we mean just this, that the compression took place from the 
 absolute vacuum line A, and the steam valve opened considerably before the 
 piston arrived at the end of its stroke or the dead center. This line will be 
 frequently found upon modern constructed engines where an attempt at high 
 speed has been made, but it is not desirable. The difference between exces- 
 sive compression or steam lead, and correct compression is simply this, if the 
 valve is shut before the exhaust is complete, or slightly before the piston 
 arrives at the end of the stroke, a small amount of low tension steam is com- 
 pressed gradually to a higher pressure, and consequently to a higher temper- 
 ature, audit offers mechanically a "cushion*' upon which the piston gradually 
 strikes, and it comes to a more gentle stop than as if nothing were there, 
 when there would be a certain amount of strain upon the gibs, keys and con- 
 nections, if the cushion were not present ; and with the cushion an amount of 
 steam is saved, and the wear and tear on the connections of the piston rod, 
 cross-head, connecting-rod, crank-pin is reduced. 
 
 For any variation from the ideal diagram there is always some reason, 
 and the beginner or the man who has had practice, should aim to obtain the 
 most perfect results that are possible, and, in every instance, to investigate 
 every departure from the theoretical, unless, as in some of the instances 
 given, the simple outline of a card shows an exceedingly faulty construction ; 
 
254 TWENTY YEARS WITH THE INDICATOR. 
 
 and it is sometimes well for a person who has not had much experience to 
 study these very faulty cards for his own benefit and future reference. 
 
 With a view to some contrast we have introduced Fig. 170, which is from 
 a Corliss engine, overloaded and throttled, or choked in the steam supply. 
 Referring to this figure (170), A represents the atmospheric line of the instru- 
 ment, B absolute vacuum, C steam-boiler pressure, D highest initial pressure 
 realized, which is only 33 pounds out of 38. The steam line from D to E, 
 supposing E to be the point of cut-off, shows 8 pounds less steam pressure 
 at the point of cut-off than at initial. This is caused by the feed pipe being 
 too small, and contrasts strangely with the ideal line E in Fig, 169. The 
 point of cut-off at E, 170, will be seen to have been rounded over, which is 
 caused by the slow closing of the valve, and the expansion line in this case 
 may proceed closely on the theoretical line, if he can find the exact point of 
 cut-off. F is the point of release or evident opening of the exhaust valve, and 
 
 o) 
 
 / 1 
 
 / f 
 
 I/ ! 
 
 FIG. 171. 
 
 G is the commencement of the vacuum, and it will contrast very strongly 
 with the ideal line in Fig. 169, as shown, and in this case (170) the engine 
 runs back to nearly one-third stroke before the maximum amount of vacuum 
 is obtained. At H the compression commences and closes at I above the 
 atmospheric line ; while the steam line from I to D, Fig. 170, shows that the 
 valve commences to open very slightly before the piston arrives at the ex- 
 treme end of its stroke. 
 
 In Fig. 171 we have another type of very frequently-found trouble w T hich 
 is more marked in this case from the fact that it is from a Corliss engine. 
 Many engineers have an idea that they must invariably get an engine under 
 motion with a partly closed throttle valve. A Corliss engine that will not 
 start with a throttle valve half open or more, is decidedly out of adjustment. 
 In this case we will not, however, discuss anything except those points which 
 the learner most frequently desires to have thoroughly fixed in his mind. The 
 
TWENTY YEARS WITH THE INDICATOR. 255 
 
 coarsely dotted diagram, if we start at the point D, shows that the 
 steam valve opens too late ; at the top of the line, directly under the letter H, 
 it will be seen that the steam line leans to the left, or away from the vertical 
 line F. The peculiar shape of the steam line, from H down to E, is caused 
 by the throttle valve being so nearly closed that steam enough is not 
 furnished to keep the pressure up to the line of realized pressure C ; conse- 
 quently the cut-off valve is held open for a greater proportion of the stroke 
 than would be were the throttle valve wide open, in which case the pressure 
 C would only be realized. At E we find the visible point of cut-off, or near 
 enough for practical purposes, is 21 pounds below the pressure at H, while 
 the expansion line runs below the atmospheric, making a loop. This loop is, 
 in all cases, resistance, and should be so figured in computing the diagram 
 for power. If we follow the exhaust line on the return stroke of the piston, 
 we find a square corner at the terminal of the exhaust, and the steam line 
 commences, leaving the vertical line F more and more, which shows that the 
 opening of the valve is entirely too late. The fine dotted line shows the 
 eccentric rolled forward on the shaft to bring the steam line from the point D 
 up to the vertical line F, or so that the valve commences to open and admit 
 the steam as soon as the engine gets upon the dead center. It is a fact, that 
 whenever the valve is late in its opening, the pressure of steam is invariably 
 reduced, and the later the valve is in its opening, the greater the reduction of 
 realized pressure. In this case, after the eccentric has been thrown forward 
 to bring the steam line proper up to the vertical line F, which is at right 
 angles to the vacuum A, and atmospheric B, as well as the realized pressure 
 in the first case, C, it will be seen that the realized pressure on the piston in- 
 creased nearly five pounds, or to the line G. In this case the throttle valve is 
 wide open ; notice the beauty of the expansion line J, which we have only 
 drawn until it reaches the exhaust line at about the point B. This would 
 make decidedly more of a loop than the coarser dotted diagram, but in mov- 
 ing the eccentric forward we have also accomplished another very important 
 and economical point, which is the compression. Notice the fine dotted line 
 I, which compresses the steam 23 pounds to the point D, at which point the 
 steam valve commences to open and fills the cylinder with steam the balance 
 of the 56 pounds. Both these objects, viz., opening the steam valve at the 
 proper time and closing the exhaust valve quicker, are accomplished in this 
 case by moving the eccentric about three-quarters of an inch of the circumfer- 
 ence of the shaft forward. Sometimes when this is done we may throw one 
 valve exactly up to the right point and the other one may be too quick, or 
 to give too early a steam line, and it may affect the exhaust valve or com- 
 pression and release in the same way. Get the steam valves right by means 
 of the jim-crank connection, and on the Buckeye engine, get them right by 
 the compensation arrangement on the valve rod, by which you can divide 
 the travel of the valve, or any difference in the travel to the hundredth of an 
 inch. In the Armington & Sims engine this is usually done at the shop, but 
 in case of tinkering or changes, take off the valve chest cover, and move the 
 check-nuts on either end of the valve until you have it exactly where you 
 
256 TWENTY YEARS WITH THE INDICATOR, 
 
 want it, and whenever any changes on the engine are made in this way, pay 
 no attention to prick-punch marks, cold-chisel slashes, or anything of that 
 sort, work by the lines of the indicator, taking care that they are perfectly 
 correct in their motion, corresponding to an absolute reduction from the 
 travel of the piston. In this way no difficulty will be found in adjusting 
 the valves of a Corliss engine to an exactness that will give a small fraction 
 of a horse-power difference on a large engine between the ends. 
 
 On some of the slide-valve engines, it is exceedingly difficult to balance, 
 for we frequently find the travel of the valve not correctly calculated, in 
 which case we must work for the best good of most of the factors in the 
 combination. Sometimes we have to sacrifice a little on the steam line for 
 the sake of being sure of a good release, and at other times we get a release 
 without compression for the sake of admitting the greatest amount of 
 pressure. 
 
 But there are other methods of attaching the indicator which are very 
 valuable. Fig. 172 shows two different diagrams taken at different times, 
 
 *_. A-= ----- -4 
 
 
 C 
 
 FIG. 172. 
 
 but both for the same purpose. These are what are termed steam-chest or 
 steam-pipe diagrams ; they are taken by attaching the steam engine indi- 
 cator to the steam chest where possible, or to the steam pipe below the 
 throttle Valve, and connecting the indicator with the same motion by a 
 separate cord (taking pains that no angles except right-angles are made) 
 with which the indicators at the end of the cylinder are driven. Care should 
 be taken to make the steam pipe diagram of the same length, as nearly as 
 possible, with the diagram from each end of the cylinder. In that case the 
 proportions between them are precise, while in the case of a longer or shorter 
 one it requires figuring to learn their proportions. 
 
 Fig. A, 172, was taken in 1868 from a Harris-Corliss engine, scale 30, to 
 ascertain what proportion of boiler pressure was realized, and a little study 
 of the diagram will satisfy any engineer that these steam-pipe or steam-chest 
 diagrams are quite as valuable as those taken from the end of the steam cyl- 
 inder, and frequently they give us a clue to what occurs before the steam 
 
TWENTY YEARS WITH THE INDICATOR. 257 
 
 reaches the steam chest, so that we may not pull the engine down but rather 
 pull down the pipe and go back to find the trouble. If we start at figure 1 
 and follow the line in the direction of the arrow to 2, we find that the press- 
 ure in the steam chest is slowly diminished, while the valve at that end of 
 the cylinder is held open, and this distance from 1 to 2 shows the exact 
 distance that the valve was held open, or until it completely closes, in feeding 
 the cylinder with the amount of steam allowed by the position of the regu- 
 lator cams at that instant of time. The valve commenced to close at 2 and 
 the pressure gradually increased up to 3 ; the valve was at that time fully 
 closed and the pressure ran along to just beyond A, where the pressure 
 dropped slightly by the draft of steam in the pipe. At 4 the other end of 
 the valve opened and steam was carried from 4 to 5, at which point the valve 
 commenced to close and made a more abrupt closing from 5 to 6 than from 2 
 to 3. 
 
 This diagram in itself is one of the finest we have ever taken, and if 
 carefully taken, they tell the action of the steam in the pipe, precisely how 
 far steam is carried on the cylinder, when the valve opens and when it closes, 
 and every fluctuation of pressure which occurs in the pipe from beginning to 
 end. Fig. B, 172, is from a Buckeye engine, at the American Institute Fair 
 in New York, taken in November, 1884, scale 50. This engine was running 
 from 222 to 225 revolutions, and it presents a contrast to the other diagram, 
 from the fact that a large amount of compression was shown upon the right- 
 hand end and a moderate amount upon the other. At figure 1 the pressure 
 falls with the opening of the valve in the steam pipe, is immediately raised 
 by too much compression, and this occurs while there is but a very slight 
 movement on the part of the piston toward the completion of its stroke. 
 The steam pressure is then led off by the opening of the valve, toward B, 
 falling off very little indeed. It will be noticed that the curve on the Buck- 
 eye engine, formed by the closure of the valve, is somewhat longer than 
 that on the Harris-Corliss engine from 2 to 3. The Buckeye uses the slide 
 valve, the motion is slightly slower, although it is very fast. We then 
 reach the highest limit of pressure. On the other end of the engine, at 
 the commencement of the stroke, or opening, the pressure slightly dimin- 
 ishes, holds steady for the first half of admission and then the pressure 
 slightly falls away, until the time of the closing of the valve. Both dia- 
 grams are very fine and show the difference in practice between the valves ; 
 C in both cases represents the atmospheric line. When these steam-pipe or 
 steam-chest diagrams are of exactly the same length as the cylinder dia- 
 gram, they are exceedingly useful, and they should be taken from every 
 engine that has indicator connections or attachments. 
 
 Another good place for the indicator to be attached is to vlie exhaust 
 pipe between the engine and the heater, or between the engine and con- 
 denser. Care must be taken, however, in the case of a condensing engine 
 whenever the indicator is to be applied, never to turn the three-way cock 
 so as to break the connection between the condenser and steam engine cyl- 
 inder. In the case of a condensing engine, we can frequently find where a 
 
*58 TWENTY YEARS WITH THE INDICATOR. 
 
 part of the difference between the vacuum gauge and realized vacuum is 
 accounted for ; in the case of a high-pressure engine we frequently obtain 
 from this a back pressure of from one-half to two or three pounds, and in 
 cases where the steam is returned or changed in its direction through the 
 feed-water heater, we sometimes find that the heaters have not the same area 
 in their tubes as the exhaust pipe has. All of these things the indicator is 
 perfectly applicable to, and with proper connections will be found of great 
 value, or quite as much so as in the case of the cylinder itself. 
 
 It is also interesting to indicate steam pumps or water pumps, as we 
 sometimes get a very curious record of the operations which go on inside 
 a cylinder, to show us that the pump throws w r ell one way and not well the 
 other ; and it is often to our advantage to examine these things, for we may 
 find the valves on one end of the pump seriously out of order, and in that 
 way avoid trouble in case of fire, or when the pump is called upon suddenly 
 to do its utmost work. In some cases of steam-pipe throttling, it is well 
 to have diagrams taken from different parts of the pipe (the motion can be 
 readily transferred to almost any distance by using carrier pulleys) and in 
 this way we frequently locate troubles, where nothing but taking down a 
 large steam drum or main steam pipe would allow the object to be accom- 
 plished otherwise. 
 
 It is well for the beginner to also practice somewhat with different 
 motions, to ascertain which are correct and which are incorrect. Get the 
 length of your travel on the diagram on the paper cylinder, then divide this 
 into four equal parts, or into as few or as many parts as you choose, turn the 
 engine over carefully, and, if you are using the pendulum, you will soon 
 find that you cannot make a peg, traveling the arc of a circle, conform 
 to the exact divisions of the travel of the cross-head on the paper cylinder. 
 
 Another point, which frequently makes trouble for beginners, is the 
 deducting the piston-rod area from the effective area of the cylinder. The 
 crank end of the engine has the size of the piston rod to be deducted from 
 the area of the piston ; beginners sometimes are troubled by not knowing 
 whether this should be taken from both ends, or from one end. It can only 
 be taken from the end that it exists on. If we have a piston 30 inches in 
 diameter, and a piston rod 3 inches in diameter, we take the area of the 
 3-inch piston rod from the area of the 20-inch piston ; the difference is insig- 
 nificant, but the beginner may as well figure it for a few times and ascertain 
 that it is an almost unimportant factor, unless in the case of steamship 
 engines, where we sometimes have a piston 120 inches in diameter, with a 
 trunk varying from 36 to 50 inches ; it then becomes an element of very 
 great importance. A great many hints as they occurred in practice, will be 
 found in the various lessons preceding this, and they can only be properly 
 studied by carefully studying each lesson by itself, for they are best remem- 
 bered when the circumstances under which they occurred, are recorded. 
 
TWENTY TEAMS WITH THE INDICATOR. 
 
 LESSON LXXXIV. 
 
 WATER PER HORSE-POWER FROM THE DIAGRAM, OR STEAM CONSUMED. 
 
 It is very frequently necessary to make a computation either upon the 
 amount of steam per horse-power, or the amount of water per horse-power 
 accounted for by the diagram. These matters are to a certain extent com- 
 plex ; not, however, from necessity or reality, but because they have fre- 
 quently been made to appear complex by the amount of figures incorporated 
 into them. All computations, as we have stated, must be from the absolute 
 vacuum, for on that line is founded the temperature, volume, weight and 
 other properties of steam. The reader of this volume will by this time have 
 become familiar with the reasons why this base line is assumed in every case 
 as the only basis of actual comparison. If we wish to ascertain the amount 
 of steam consumed from the diagram, or, as it is frequently termed, steam 
 accounted for by the indicator, we take the absolute vacuum at 14. 7 "below the 
 atmospheric line of the diagram. For real correctness the clearance of the 
 engine must be known, and this amount, the clearance, should be added to 
 the diagram on a scale equal to the scale of the diagram. If the diagram is 
 four inches long and represents a stroke of four feet, five feet, ten feet, or twelve 
 feet, it is easy to ascertain precisely what any fraction of the four inches 
 represents proportionately. Add to the diagram of the indicator the clear- 
 ance, if you can, and this clearance must include the cubic inches between 
 the piston and the cylinder head at full stroke ; also, the exhaust port to 
 the face of the valve, and the steam port to the face of the valve as well. 
 It is usual to figure the amount of steam consumed, or accounted for, from 
 the point of release. This is not necessary, and sometimes it is absolutely 
 impossible, to tell precisely where release commences. Take any point on 
 the line, either at the point of cut-off, or on any point of the expansion line 
 before the exhaust valve opened. Now take the length of the stroke, in- 
 cluding the clearance, up to the point where the pressure is measured, and 
 from which point the computation is to be made. Multiply the length of 
 the stroke to that point by the area in square inches of the cylinder ; this 
 will give you the volume of the cylinder to that point, and to this amount 
 must be added the number of square inches of clearance up to the point of 
 the computation, this gives the volume of the cylinder ; multiply by the 
 pressure to the point of computation ; divide this product by 14.7 ; this 
 quotient gives; the number of cubic inches of steam at the pressure of the 
 atmosphere discharged from the cylinder at a single stroke, or to that point 
 of the stroke where the pressure is taken. If there is no leak in the valves, 
 and the steam is not saturated with water, the cubical contents of the cylin- 
 
260 TWENTY YEARS WITH THE INDICATOR. 
 
 der multiplied by the pressure at the point of cut-off should exactly coincide 
 with the cubic contents multiplied by the pressure at the actual point of 
 release. If both cut-off and release are well defined, it is a good plan 
 always to make both these computations, and it will frequently be found 
 that the point of release gives the greatest amount. This at once shows a 
 leak. In a compound engine the cubic contents of both cylinders should 
 agree with each other, if the computation is made in this way from the points 
 of release in both cases. Having reached the cubic inches of steam at 
 the pressure of the atmosphere, multiply this by the number of strokes in an 
 hour, and don't get confused, you are working upon one side of the piston 
 only ; take care that revolutions are not considered, for in the one case you 
 will get double, and in the other half the actual result. Having multiplied 
 by the number of strokes in an hour, or the number of times that end of the 
 cylinder is filled with steam in an hour and exhausted, divide this product by 
 1728, the number of cubic inches in a foot, in order to reduce cubic inches to 
 cubic feet. We have now the number of cubic feet of steam used per hour, 
 divide this by the indicated horse-power of the diagram and you have the 
 cubic feet of steam per horse-power per hour. If the amount of water used 
 or accounted for is required, divide the number of cubic feet of steam per 
 hour by 1700, this gives the cubic feet of water used per hour. If pounds of 
 water are wanted, multiply the last result by 62^ ; or, if gallons are wanted, 
 divide the product by 8.33 pounds for wine gallon. Care must be taken in 
 making these computations to get at the average or actual power required. It 
 is hardly possible for the indicator to account for all the steam consumed or 
 all the water used, for as a matter of fact any excess of leakage, or any 
 change of circumstances, such as blowing- off, will require a larger amount of 
 water in the boiler than the indicator can account for ; the indicator simply 
 accounts for what is used at and in the engine, and the indicator cannot ac- 
 count for leakage from any cause. 
 
 Or, to repeat the formula in a different way, without the explanations, 
 obtain the volume of the cylinder to any point which is perfectly plain, be- 
 tween the point of cut-off and the point of release ; this is in cubic inches, 
 and must be multiplied by the pressure at the above point from the vacuum ; 
 then divide by 14.7, the pressure of steam at the atmospheric pressure, this 
 gives in cubic inches the amount of steam discharged at each stroke. This 
 quotient is multiplied by the number of strokes or times that the cylinder is 
 filled at one end per hour ; .this gives the total number of cubic inches of 
 steam accounted for by the number of strokes which are made in one hour ; 
 this is reduced to cubic feet by dividing by 1728, which gives cubic feet of 
 steam. Divided the cubic feet of steam by 1700, the volume of steam at 
 atmospheric pressure, and the result gives us cubic feet of water ; multiply 
 this last result by 62^ and we have pounds of water ; this divided by the 
 horse-power gives us pounds of water per horse-power for one hour. 
 
TWENTY YEARS WITH THE INDICATOR. 261 
 
 ANOTHER METHOD OF COMPUTING THE WATER PER HORSE-POWER 
 
 PER HOUR. 
 
 The volume of the cylinder multiplied by the number of strokes per 
 minute, multiplied by 60, or the minutes per hour, divided by 1728, gives 
 cubic feet. Multiply the last result by the weight of a cubic foot of steam at 
 the pressure at the point of cut-off or the point from which the computation 
 is made, using the pressure above absolute vacuum and divide this last by 
 the horse-power, and the final result will be pounds of water per horse-power 
 per hour. (See table of "Properties of Saturated Steam" for weight of one 
 cubic foot in decimals of a pound.) 
 
 VACUUM. 
 
 TEMPERATURE AT DIFFERENT ''POUNDS PER SQUARE INCH" AND 
 
 " INCHES OF MERCURY." 
 
 The very peculiar position in which we are placed in using one or the 
 other of the thermometer scales, now generally in use or cited by scientific 
 men in experiments, or in contrast or comparison of results, makes an 
 enormous amount of trouble and bungling by comparing all others with 
 the Fahrenheit scale which commences on an assumption over 300 from 
 correct and ends in a guess, or, as Mr. Porter has so aptly said, " begins in a 
 blunder and ends nowhere." 
 
 Fahrenheit assumes 32 as freezing, and 212 as boiling. Centigrade 
 gives as corresponding to freezing on the F. scale, and 100 on his ther- 
 mometer to boiling, or 212 on the F. The general adoption of the Centi- 
 grade scale for scientific purposes, ai home and abroad, should be much more 
 general, as the F. does not commence with fact or continue with accuracy. 
 
 TOTAL HEAT. 
 
 There is no term used which is more of a misnomer. Absolute cold has 
 been determined with all reasonable certainty as 459 to 461 below the arbi- 
 trary point as assumed by Fahrenheit, so that in the tables of all scientific 
 works ' total heat " is a false application of a term, notably in some of the 
 literature which has emanated from the United States Bureau of Steam 
 Engineering, and total heat expresses only from Fahrenheit's assumed zero. 
 
262 TWENTY YEARS WITH THE INDICATOR. 
 
 INCHES OF MERCURY. 
 
 Usage has confirmed the use of a scale as rude as the tally stick of 
 ball players in our younger days, when notches were cut in a stick with no 
 graduation or calculation, simply guessed at. The English government have 
 adopted at the Koyal Arsenal at Woolwich, mercurial gauges based on 
 equal divisions from the " standard of usage," that 15 pounds to the square 
 inch equals 30 inches of mercury, and the curious feature of these "standard" 
 gauges to us, on examination, was the fact that each pound pressure coincided 
 with even inches. 
 
 The expansion of mercury for each increase in its temperature of one 
 degree F. equals .000100854 inch. 
 
 The starting point is, mercury at 32 F. equals a volume of 1, and as the 
 changes in temperature occur if mercury is to measure the changes then we 
 must correct the column of mercury for the degrees. Hence it follows that 
 inches of mercury do not follow any assumed or empirical scale of equal 
 inches, and when so combined neither element shows a correct reading. 
 
 One pound pressure in inches of mercury equals 2.03601 inches. 
 
 The specific gravity of mercury is 13.595 + . 
 
 Water is at its greatest density at 39^2 F. or 4 C., and M. Regnault has 
 brought out some curious facts in his elaborate experiments on air, water 
 and steam ; and these are so extensive and so valuable that all persons who 
 study steam should have them at hand. 
 
 He has determined that saturated steam cannot be investigated separately 
 on account of " the expansion and contraction of its volume consequent on 
 changes of pressure, and those consequent on temperature, because at the 
 same time its volume is being contracted under increasing pressure, its 
 expansion takes place with increasing temperature," so that the density of 
 saturated steam is an unsolved problem, and Mariotte gives us data approach- 
 ing exactness from formulae of air, which, under a constant pressure doubles 
 its volume on an increase of temperature of 272.8 C., or 491 F., and in tem- 
 perature of steam a confusion exists at the same pressure by different au- 
 thorities, and frequently some unexplained feature exists which may be the 
 point from which they start out, and we have to ascertain this point and add 
 or subtract 32, or some other number, frequently, in order to reconcile the 
 data given. 
 
 THE DENSITY OF STEAM is 1, divided by the volume at any given pressure, 
 and at the atmospheric pressure the volume is 1702, so that the density be- 
 comes the fraction 17 * 02 that of water at same pressure. 
 
 TEMPERATURE OF VACUUM. 
 
 The following table is from M. Regnault by transposition, and shows 
 the pounds per square inch. The temperature and the inches of mercury 
 corrected for temperature. The temperature is given by each 4 F., and the 
 
TWENTY YEARS WITH THE INDICATOR. 
 
 263 
 
 fractions are closely as possible expressed in three places in the first column, 
 and four places in the third column. 
 
 The unit of heat being the heat required to raise the temperature of one 
 pound of water 1 F., if we require to compute from any point ; the heat con- 
 tained in the water from the starting point, 32 F., must be subtracted from 
 the heat given, and we can then convert into steam from and to any pressure, 
 from any of the tables in this work : 
 
 Pounds per 
 square inch. 
 
 Temperature. 
 
 Inches of 
 Mercury. 
 
 1.127 
 
 208 
 
 2.3028 
 
 2.186 
 
 204 
 
 4.4538 
 
 3.172 
 
 200 
 
 6.4638 
 
 4.095 
 
 196 
 
 8.3428 
 
 4.954 
 
 192 
 
 10.0948 
 
 5.755 
 
 188 
 
 11.7258 
 
 6.497 
 
 184 
 
 13.2418 
 
 7.190 
 
 180 
 
 14.6508 
 
 7.833 
 
 176 
 
 15.9588 
 
 8.427 
 
 172 
 
 17.1718 
 
 8.978 
 
 168 
 
 18.2948 
 
 9.489 
 
 164 
 
 19.3338 
 
 9.959 
 
 160 
 
 20.2928 
 
 10.393 
 
 156 
 
 21.1768 
 
 10.792 
 
 152 
 
 21.9928 
 
 11.162 
 
 148 
 
 22.7428 
 
 11.499 
 
 144 
 
 23.4318 
 
 11.811 
 
 140 
 
 24.0638 
 
 12.093 
 
 136 
 
 24.6418 
 
 12.352 
 
 132 
 
 25.1718 
 
 12.591 
 
 128 
 
 25.6548 
 
 12.807 
 
 124 
 
 26.0958 
 
 13.004 
 
 120 
 
 26.4968 
 
 Pounds per 
 square inch. 
 
 13.182 
 13.345 
 13.493 
 13.624 
 13.743 
 13.852 
 13.948 
 14.035 
 14.114 
 14.183 
 14.245 
 14.300 
 14.350 
 14.393 
 14.431 
 14.465 
 14.495 
 14.521 
 14.543 
 14.563 
 14.581 
 14.596 
 
 Temperature. 
 
 116 
 
 112 
 
 108 
 
 104 
 
 100 
 
 96 
 
 92 
 
 88 
 
 84 
 
 80 
 
 76 
 
 72 
 
 68 
 
 64 
 
 60 
 
 56 
 
 52 
 
 48 
 
 44 
 
 40 
 
 36 
 
 32 
 
 Inches of 
 Mercury. 
 
 26.8608 
 27.1908 
 27.4908 
 27.7588 
 28.0038 
 28.2238 
 28.4218 
 28.5988 
 28.7588 
 28.8988 
 29.0249 
 29.1374 
 29.2372 
 29.3256 
 29.4038 
 29.4726 
 29.5335 
 29.5867 
 29.6334 
 29.6742 
 29.7097 
 29.7407 
 
 As 32 F. is the freezing point we stop at that point, as there would be 
 no economy in going to that point, even if it were a possibility. The point 
 of greatest economy by marine engineers is now considered to be about 124 
 F., at which point the changes of temperature are not so radical as with more 
 vacuum, and a greater degree of cold in its action on the surfaces of piston 
 and cylinder. 
 
 We believe in a less vacuum as a means of greater economy ; and that 
 some of the examples of compounding, as shown in this work, are but an 
 approach to the highest economy in the application of steam to motive 
 power. 
 
264 TWENTY YEAH.S WITH THE INDICATOR. 
 
 HEIGHT OF WATER COLUMN DUE TO UNBALANCED PRESSURE IN 
 CHIMNEY ONE HUNDRED FEET HIGH. 
 
 Temperatni 
 in the 
 Chimney. 
 
 e 
 
 Temperature of the External Air Barometer, 14.7. 
 
 
 
 10 
 
 20 
 
 30 
 
 40 
 
 50 
 
 60 
 
 70 
 
 80 
 
 90 
 
 1OO 
 
 200 
 
 .453" 
 
 .419 
 
 .384 
 
 .353 
 
 .321 
 
 .292 
 
 .263 
 
 .234 
 
 .209 
 
 .182 
 
 .157 
 
 210 
 
 .470 
 
 .436 
 
 .401 
 
 .371 
 
 .338 
 
 .339 
 
 .280 
 
 .251 
 
 .227 
 
 .200 
 
 .175 
 
 220 
 
 .488 
 
 .453 
 
 .419 
 
 .388 
 
 .355 
 
 .326 
 
 .28 
 
 .269 
 
 .244 
 
 .217 
 
 .192 
 
 230 
 
 .505 
 
 .470 
 
 .436 
 
 .405 
 
 .372 
 
 .344 
 
 .315 
 
 .286 
 
 .261 
 
 .234 
 
 .209 
 
 240 
 
 .520 
 
 .488 
 
 .451 
 
 .421 
 
 .388 
 
 .359 
 
 .330 
 
 .301 
 
 .276 
 
 .250 
 
 .225 
 
 250 
 
 .537 
 
 .503 
 
 .468 
 
 .438 
 
 .405 
 
 .376 
 
 .347 
 
 .319 
 
 .294 
 
 .267 
 
 .242 
 
 260 
 
 .555 
 
 .528 
 
 .484 
 
 .453 
 
 .420 
 
 .392 
 
 .363 
 
 .334 
 
 .309 
 
 .282 
 
 .257 
 
 270 
 
 .568 
 
 .534 
 
 .499 
 
 .468 
 
 .436 
 
 .407 
 
 .378 
 
 .349 
 
 .324 
 
 .298 
 
 .273 
 
 280 
 
 .584 
 
 .549 
 
 .515 
 
 .482 
 
 .451 
 
 .422 
 
 .394 
 
 .365 
 
 .340 
 
 .313 
 
 .288 
 
 290 
 
 .597 
 
 .563 
 
 .528 
 
 .497 
 
 .465 
 
 .436 
 
 .407 
 
 .379 
 
 .353 
 
 .326 
 
 .301 
 
 300 
 
 .611 
 
 .576 
 
 .541 
 
 .511 
 
 .478 
 
 .449 
 
 .420 
 
 .392 
 
 .367 
 
 .340 
 
 .315 
 
 310 
 
 .624 
 
 .589 
 
 .555 
 
 .524 
 
 .492 
 
 .463 
 
 .434 
 
 .405 
 
 .380 
 
 .353 
 
 .328 
 
 320 
 
 .637 
 
 .603 
 
 .568 
 
 .538 
 
 .505 
 
 .476 
 
 .447 
 
 .419 
 
 .394 
 
 .367 
 
 .342 
 
 830 
 
 .651 
 
 .616 
 
 .582 
 
 .551 
 
 .518 
 
 .489 
 
 .461 
 
 .432 
 
 .407 
 
 .380 
 
 .355 
 
 340 
 
 .662 
 
 .638 
 
 .593 
 
 .563 
 
 .530 
 
 .501 
 
 .472 
 
 .443 
 
 .410 
 
 .392 
 
 .367 
 
 350 
 
 .676 
 
 .641 
 
 .607 
 
 .576 
 
 .543 
 
 .514 
 
 .486 
 
 .457 
 
 .432 
 
 .405 
 
 .380 
 
 360 
 
 .687 
 
 .653 
 
 .618 
 
 .588 
 
 .555 
 
 .526 
 
 .497 
 
 .468 
 
 .444 
 
 .417 
 
 .392 
 
 370 
 
 .699 
 
 .664 
 
 .630 
 
 .599 
 
 .565 
 
 .538 
 
 .509 
 
 .480 
 
 .455 
 
 .428 
 
 .403 
 
 380 
 
 .710 
 
 .676 
 
 .641 
 
 .611 
 
 .578 
 
 .549 
 
 .520 
 
 .492 
 
 .467 
 
 .440 
 
 .415 
 
 390 
 
 .722 
 
 .687 
 
 .652 
 
 .622 
 
 .589 
 
 .561 
 
 .532 
 
 .503 
 
 .478 
 
 .451 
 
 .426 
 
 400 
 
 .732 
 
 .697 
 
 .662 
 
 .632 
 
 .598 
 
 .570 
 
 .541 
 
 .513 
 
 .488 
 
 .461 
 
 .436 
 
 410 
 
 .743 
 
 .708 
 
 .674 
 
 .643 
 
 .610 
 
 .583 
 
 .553 
 
 .524 
 
 .499 
 
 .472 
 
 .447 
 
 420 
 
 .753 
 
 .718 
 
 .684 
 
 .653 
 
 .620 
 
 .591 
 
 .563 
 
 .534 
 
 .509 
 
 .482 
 
 .457 
 
 430 
 
 .764 
 
 .730 
 
 .695 
 
 .664 
 
 .632 
 
 .602 
 
 .574 
 
 .545 
 
 .520 
 
 .493 
 
 .468 
 
 440 
 
 .774 
 
 .739 
 
 .705 
 
 .674 
 
 .641 
 
 .612 
 
 .584 
 
 .555 
 
 .530 
 
 .503 
 
 .478 
 
 450 
 
 .783 
 
 .749 
 
 .714 
 
 .684 
 
 .651 
 
 .622 
 
 .593 
 
 .564 
 
 .540 
 
 .513 
 
 .488 
 
 460 
 
 .793 
 
 .758 
 
 .724 
 
 .694 
 
 .660 
 
 .632 
 
 .603 
 
 .574 
 
 .549 
 
 .522 
 
 .497 
 
 470 
 
 .802 
 
 .768 
 
 .733 
 
 .703 
 
 .670 
 
 .641 
 
 .612 
 
 -584 
 
 .559 
 
 .532 
 
 .507 
 
 480 
 
 .810 
 
 .776 
 
 .741 
 
 .710 
 
 .678 
 
 .649 
 
 .620 
 
 .591 
 
 .566 
 
 .540 
 
 .515 
 
 490 
 
 .820 
 
 .785 
 
 .751 
 
 .720 
 
 .687 
 
 .659 
 
 .630 
 
 .601 
 
 .576 
 
 .549 
 
 .524 
 
 600 
 
 .829 
 
 .791 
 
 .760 
 
 .730 
 
 .697 
 
 .669 
 
 .639 
 
 .610 
 
 .586 
 
 .559 
 
 .534 
 
TWENTY YEAKS WITH THE INDICATOR 
 
 HOW TO TEST FEED WATEE FOK BOILERS. 
 
 Feed-water heaters are a matter of great importance ; they are not 
 always put in as they should be, nor are they given credit for all that they 
 cto, or even all that they are capable of, and in a great many cases they are 
 nor used, as they might be, for the profit or benefit of the owner. Testing 
 the temperature of feed water for a boiler, is not an agreeable or desirable 
 undertaking at all times, but it is a matter which can be done every hour in 
 the day, if the engineer in charge will only think so. It is a matter not gen- 
 erally understood, that the feed water varies a great deal whether it is tested 
 under pressure or in the open air. Water cannot and will not show any 
 temperature greater than 212, if, indeed, it does that, unless it is under 
 pressure. It is remarkable that engineers will insist in drawing water out of 
 a boiler under 60 or 80 pounds pressure, and dip a thermometer in the cur- 
 rent of water which is running away from the boiler into the open air, and 
 then wonder why the feed water does not show the same result ! If the 
 reader will refer to Fig. 1, in which A represents a side of the feed-water 
 heater, B the feed pipe to the boiler from the upper portion of the heater, C, 
 D, E, F, are all for the testing of feed water, and will be explained further 
 on. Fig. 3 is a crude, but simple and reliable, method of testing any ther- 
 mometer, and it is a very desirable proceeding to test thermometers, for we 
 have found them varying 15 to 20 from the standard which we have, and 
 always refer to in any test of pressure, or steam, or for temperature of feed 
 water, whenever we are working around boilers or in any steam work. Take 
 a tin can or pail, anything which will hold water three inches deep or over 
 that, and put it upon a fire, or anywhere else, to boil ; when it is boiling, 
 then enter the thermometer bulb into the water an inch or more in depth, and 
 notice whether it records 212 or 220, or any other point, and also notice 
 that the water is kept boiling until the observation is complete ; whatever the 
 variation is between 212 and the record of the test, remember that and make 
 the allowance in all future observations taken with that thermometer. 
 It is very seldom that we find a thermometer which shows less than 212 at 
 boiling. 
 
 If we refer to Fig. 1 again, there is a cross put in the feed pipe from the 
 heater to the boiler, from which the feed pipe proper leads off at B, the pipe 
 which is continued down to C, branches off again at D, having an outlet, say 
 one quarter of an inch in diameter upon one side and one and one-half inches 
 upon the other. We have found these arrangements sometimes put upon the 
 heater of one maker by another who was desirous of making a test of his 
 opponent's feed-water heater, and it is somewhat curious that the most of 
 these tests are made by means of thermometers exposed to the open air. 
 
2 66 
 
 TWENTY YEARS WITH THE INDICATOR, 
 
 while, as a matter of fact, the heater is used in its e very-day work " under 
 pressure ;" the temperature of the water drawn from the boiler itself, will not 
 be over 212, if tested at the point D or E, no matter if the boiler was ten feet 
 distant, and the pressure 80 pounds. 
 
 We will now refer to Fig. 2, in which A represents the glass tube of the 
 thermometer correctly graduated, and used only after it has been thoroughly 
 tested, D is a cast-iron plug which fits into the top of the cross, immediately 
 over the boiler feed pipe B, Fig. 1 ; into the top of D is drilled the hole for a 
 half -inch gas-pipe plug B, which has been cupped out, and under it a piece of 
 rubber packing, C, fitted. The holes in B and D are slightly larger than the 
 thermometer tube, and the rubber is punched so as to fit close ; when 
 
 Fi.2 
 
 the tube has been put into place, the rubber slipped down upon it, and the 
 plug, B, screwed up, so that the bulb will be held below the crossing of the 
 other pipe, we are ready to put the plug into the top of the cross and com- 
 mence operations. As a safeguard the cord E is led from a small peg in each 
 side of the plug through the ring in the top of the thermometer, so as to pre- 
 vent its moving up by the pressure. In this disposition of the thermometer 
 the boiling point should always be left above the top of the plug. 
 
 With this arrangement, which any engineer can readily fix up for himself, 
 it is perfectly easy to test correctly and completely what the temperature of 
 feed water is, which is passing into the boiler, and it can be done for fifty 
 cents beyond the price of the thermometer, and these, from a reliable maker, 
 will cost from $1.30 to $1.50 each. If there is an angle valve in the feed 
 near the boilers, it is a first-rate place in which to put the thermometer so as 
 
TWENTY YEARS WITH THE INDICATOR. 267 
 
 to know at what temperature the water enters the boilers, but whenever the 
 apparatus is put in, let the bulb of the thermometer always remain in the 
 current of water which is under pressure. Water boils at the level of the 
 sea at 212, and for each 500 feet above the level of the sea, it boils at one 
 degree less than 212 ; never test steam or water under pressure unless you 
 put the thermometer into the current of moving water or steam. 
 
 LUSTEKLESS FINISH ON TEMPEEING STEEL. 
 
 A fine lusterless surface on tempered steel can be procured by either of 
 the following operations : After the steel article has been tempered, it should 
 be rubbed on a smooth iron surface with some pulverized oil-stone until it is 
 perfectly smooth and even, then laid upon a sheet of white paper and rubbed 
 back and forth until it acquires a fine dead finish. Any screw holes or de- 
 pressions in the steel must be cleaned beforehand with a piece of wood and 
 oil-stone. This delicate, lusterless surface is quite sensitive, and should be 
 rinsed with pure, soft water only, when the article will be found to have a 
 fine, lusterless finish. 
 
 PATTEEN YAENISH. 
 
 A varnish has been patented in Germany for foundry purposes and 
 machinery, which it is claimed dries as soon as put on, gives the patterns a 
 smooth surface, and is a good filler. This varnish is prepared in the follow- 
 ing manner : Thirty pounds of shellac, ten pounds of Manilla copal and ten 
 pounds of Zanzibar copal are placed in a vessel, which is heated externally 
 by steam, and stirred from four to six hours, after which 150 parts of the 
 finest potato spirit are added, and the whole heated during four hours to 87 
 C. This liquid is dyed by the addition of orange color, and can then be used 
 for painting the patterns. When used for painting and glazing machinery, it 
 consists of thirty-five pounds of shellac, five pounds of Manilla copal, ten 
 pounds of Zanzibar copal and 150 pounds of spirit. 
 
2 68 
 
 TWENTY YEARS WITH THE INDICATOR. 
 
 THE CALORIMETEB TEST. 
 
 RULE FOR MAKING IT. 
 
 "We give the following old but simple rule for a Calorimeter test : Take 
 steam from main pipe near boiler with ^-inch pipe the pipe must be 
 thoroughly protected by covering with hair felt ; the lower end of pipe should 
 be closed, and -inch holes drilled so as to form a rose ; the holes should be 
 close to bottom of cap, so as not to trap water; the valve should be within 
 easy reach ; a can (bright tin is preferable) holding twelve to fifteen pounds of 
 water should be provided, with sufficient opening in top to insert steam pipe 
 and take temperature ; this also should be well protected with hair felt ; a 
 small scale, steelyard, 01 spring balance, can be used for weighing ; put exactly 
 ten pounds water in the can, note its temperature, move the scale weight out 
 one pound, so as to have just eleven pounds water when test is complete ; 
 blow steam through pipe to free it of any water of condensation, insert pipe 
 in can, and when just one pound of steam has been condensed (eleven pounds 
 water in can) shut off steam and note temperature of water. The difference 
 is the caloric. 
 
 This formula is based, as all are, on the total heat of steam latent and 
 sensible, less the temperature of water above zero, and can be calculated thus : 
 Latent heat 966, sonsible 212=1178, less the temperature of 10 pounds water, 
 which leaves 1178 80=1098. Now we turn one pound steam into 10 
 pounds water, and find the temperature has risen from 80 to 176, a gain of 
 96. This we multiply by 11 pounds water, 11x96 = 1056, nearly equal to 
 our 1098 total available heat ; 100 rise of temperature, if no heat had been 
 absorbed by the can containing the water, would be dry steam. It has been 
 found by experiment that 96 under the above rule is dry steam. Had the 
 rise of temperature been but 80, the amount of water in the steam would 
 have been 20 per cent. The tables approximate closely to the actual amount 
 of water carried over in the steam : 
 
 OP TEMPERATURE OBSERVED ABOVE THE 
 SUPERHEATED STEAM. 
 
 96 degrees dry steam. 
 
 80 
 
 71 
 
 63 
 
 54 
 
 46 
 
 87 
 
 28.5 
 
 20 
 
 15 
 
 11.5 
 
 PERCENTAGE OP WATER IN STEAM. 
 
 5 per cent, water. 
 10 
 
 100 all water. 
 
TWENTY YEARS WITH THE INDICATOR. 2 6 9 
 
 IKON PAINT. 
 
 Iron paint, as it is termed a paint composed of pulverized iron and lin- 
 seed oil varnish is a recent German invention, and is intended for covering 
 damp walls, outer walls, and, in short, any place or vessel exposed to the action 
 of the open air and to the weather. Should the article to be painted be ex- 
 posed to frequent changes of temperature, linseed oil varnish and amber 
 varnish are mixed with the paint intended for the first two coats, without the 
 addition of any artificial drying medium. The first coat is applied rather 
 thin, the second a little thicker and the last in a rather fluid state. The 
 paint is equally adapted as weather-proof coating for wood, stone and iron ; 
 nor is it necessary to previously free the latter from rust, grease, etc., a super- 
 ficial cleaning being sufficient. 
 
 JOULE'S EQUIVALENT. 
 
 The conversion of heat into work is the main purpose of the steam en- 
 gine. In other words, we could not use coal in the steam cylinder, and water 
 is therefore made the medium to convey the products of combustion, trans- 
 ferred from coal to water, through the steam boiler, and the steam in the 
 fluid state, under various pressures, passes through all the pipes, valves, 
 ports, is controlled by the valves so that it is more or less economically used 
 according to their action, and the only way we have of establishing this action 
 for economical comparisons for the purpose of ascertaining the power, is by 
 means of the indicator. We must, therefore, have some standard, and for that 
 purpose frequent reference is made to the unit or equivalent. Mr. Joule, at 
 Cambridge, England, in 1845 or '46 first exhibited the apparatus, and at that 
 time he considered that it required 781.5 pounds to equal the raising of one 
 pound of water 1 Fahrenheit, while in another case it was slightly increased, 
 but was subsequently settled that the precise equivalent of the unit of heat 
 was 772 pounds raised one foot high, and this is what is termed Joule's 
 equivalent. 
 
270 TWENTY YEARS WITH THE INDICATOR, 
 
 Joule's equivalent has been generally substantiated by scientific research 
 and is accepted as true. It may be defined as the work done raising one 
 pound through one foot, and is called either the foot-pound, or the unit of 
 heat ; or the heat required to raise the temperature of a pound of water 1 
 Fahrenheit, and is the equivalent of 772 units of work. When a pound of 
 water at the temperature of boiling, 212 Fahrenheit, or 100 Centigrade, 
 when at the atmospheric pressure, passes into a state of steam of the same 
 temperature, 966.6 units of heat, equivalent to 746,215 units of work, dis- 
 appear, being converted into internal and external work. 
 
 Mr. Joule also has announced what absolute cold was, and this is con- 
 sidered proven by scientific research at 461.2 below zero of the Fahrenheit 
 scale or 274 on the Centigrade scale. The theory upon which Joule's 
 equivalent is rested is that heat is motion, and that absolute rest would be 
 absolute cold, and that the atoms of which bodies consist, are always in 
 motion, and if they were brought to absolute rest, this would give the result 
 which he first announced, and which has generally been accepted by the best 
 authorities, as 461.2 below zero, Fahrenheit. 
 
 COLOEING SOFT SOLDER YELLOW. 
 
 When brass is soldered with soft solder, the difference in color is so 
 marked as to direct attention to the spot mended. The following method of 
 coloring soft solder is given by the Metallarbeiter : First prepare a saturated 
 solution of sulphate of copper (bluestone) in water, and apply some of this on 
 the end of a stick to the solder. On touching it with a steel or iron wire it 
 becomes coppered, and by repeating the experiment the deposit of copper 
 may be made thicker and darker. To give the solder a yellower color, mix 
 one part of a saturated solution of sulphate of zinc with two of sulphate of 
 copper, apply this to the coppered spot, and rub it with a zinc rod. The 
 color can be still further improved by applying gilt powder and polishing. 
 
 On gold jewelry or colored gold, the solder is first coppered as above, 
 then a thin coat of gum or isinglass solution is applied and bronze powder 
 dusted over it, which can be polished after the gum is dry and made very 
 smooth and brilliant ; or the article may be electro-plated with gold, and then 
 it will all have the same color. 
 
 On silverware the coppered spots of solder are rubbed with silvering 
 powder, or polished with the brush and then carefully scratched with the 
 scratch brush, then finally polished. 
 
TWENTY YEARS WITH THE INDICATOR. 271 
 
 RECIPES FOE SOLDEEING FLUID. 
 
 One dram each of powdered copperas, borax and prussiate of potash ; 
 one-half ounce powdered sal ammoniac ; 3^- ounces fluid muriatic acid ; let the 
 mixture cut all the zinc it will and then dilute with one pint of water. This 
 is something extra for soldering raw edges of tin or galvanized iron. The 
 above quantity of fluid costs fifteen cents. 
 
 Add granulated zinc or zinc scraps to two fluid ounces of muriatic acid 
 until hydrogen ceases to be given off; add one teaspoonful of ammonium 
 chloride ; shake well and add two fluid ounces of water. 
 
 Also a good fluid for soldering bright tin can be made of well-pounded 
 resin and sweet oil. It was used years ago by the tinners of Great Britain 
 for soldering planished ware made in those days, and is excellent for solder- 
 ing fine work, silver and plated ware ; it can be wiped off with a clean rag and 
 leave no stain or scratches. 
 
 SAFETY-VALVE PEOBLEMS. 
 
 1. Do you wish to know the pressure of the ball as it hangs ? Ball weighs 
 90 pounds. Multiply the weight of the ball by the distance in inches the 
 weight hangs from the center of the fulcrum, say 30 ; divide that by the dis- 
 tance in inches from the center of the valve to the center of the fulcrum, say 
 5 ; add the weight of the valve and lever in pounds, say 20 ; divide this by the 
 square inches in the valve, say 20 ; and the result will be the pressure in 
 pounds on a square inch of the ball, equal to 28. 
 
 90x30^-5 + 20-^-20^28 
 
 2. If you wish a certain pressure with a ball you have never used, then 
 say the valve is 4 inches in diameter, the area is 12.566. Multiply this by the 
 pressure you want in pounds, say 40 ; subtract from it the weight of valve 
 and lever, say 16 ; multiply this by the distance from the center of the valve 
 to the center of the fulcrum, say 4 ; divide this by the weight of the ball in 
 pounds, say 80 ; and the distance in inches the ball must be from the center 
 of the fulcrum will be the result, as 24J. 
 
 12.566x40 16x4-f-80=24J. 
 
272 TWENTY YEARS WITH THE INDICATOR. 
 
 3. If you wish a ball upon the lever for a certain pressure in pounds, 
 multiply the area of the valve 7.068 by the pressure required 50 pounds, take 
 out the weight of the valve and lever ; multiply that result by the distance 
 from the center of the valve to the center of the fulcrum, say 3 inches ; divide 
 this result by the distance from where you put the ball, 21 inches, to the 
 center of the fulcrum, and this will give you the weight of the ball. 
 7.068X50X3^21 = 50^ pounds, weight of ball. 
 
 RULE FOR ASCERTAINING SIZE OF SAFETY-VALVE FOR ANY GIVEN 
 
 GRATE SURFACE. 
 
 The required aggregate area of safety-valve to be placed upon boilers, 
 may be expressed by the formula, 
 
 225XG 
 A=- 
 
 P + 8.62 
 
 in whicft A is area of safety-valve in inches ; G is area of grate in square feet ; 
 P is pressure of steam in pounds per square inch, to be carried on the boiler 
 above the atmosphere. The following table gives the results of the formula 
 for one square foot of grate as applied to boilers used at different pressures : 
 
 PBESSUEES PER SQUARE INCH. 
 
 10. 20. 30. 40. 50. 60. 70. 80. 90. 100. 110. 120. 
 
 I I I I I I I I I I I I 
 
 1.21 0.79 0.58 0.46 0.38 0.33 0.29 0.25 0.23 0.21 0.19 0.17 
 
 (area corresponding to one square foot of grate.) 
 
 Example. Bequired, area of safety-valve in square inches for boiler 
 running at 80 Ibs. pressure and 30 feet grate surface. 
 
 For 1 square foot from table at 80 Ibs. 0.25 
 Square feet grate surface .30 
 
 Area of valve in square-inches =7.50 
 
 If a forced or artificial draft is used, the estimate is based on a consump- 
 tion of 16 Ibs. of fuel for each square foot of grate surface. 
 
 This rule was furnished by the scientific commission which framed the 
 inspection law for the city of Philadelphia. 
 
 Tarnished colored gold articles, it is said, may be restored by the follow- 
 ing method : Dissolve one ounce of bicarbonate of soda, half an ounce of 
 chloride of lime, and half an ounce of common salt, in about four ounces of 
 boiling water. Take a clean brush, and wash the article with the hot solution 
 for a few seconds, and rinse immediately in two clean waters. Dry in warm 
 sawdust, and finally rub over with tissue paper. 
 
TWENTY YEARS WITH THE INDICATOR. 273 
 
 WATEE IN THE CYLINDER. 
 
 It has now become generally accepted among the best authorities that 
 the indicator diagram will show the water or presence of water in the cylinder 
 when working. It must first be positively settled that there are no leaks 
 about the valves or piston or that there is nothing which shall disturb the 
 true diagram, for unless the engine is in mechanical perfection as nearly as 
 possible, the real reading of a diagram does not give us the facts, and am- 
 biguous quantities enter in. We must, therefore, be sure that the engine is 
 mechanically in first-class condition and proper order ; then having arrived at 
 the point of the stroke where steam is cut off, with precision, we can figure 
 for water in the steam. This varies considerably with the conditions under 
 which the valves are working. If a great deal of water is present, it makes a 
 radical difference in the expansion curve. We can readily plot upon an in- 
 dicator diagram the pressure of steam with regard to its density and volume, 
 by reference to the table of Properties of Saturated Steam, if we wish to o 
 so ; but in doing this, we have certain other factors which must be taken into 
 account, which involve many figures, and also points about which the best 
 authorities differ so widely that we have not carried it out in this volume ; 
 that rather belongs to the science of the indicator than to its practice, and is 
 a point upon which the best authorities do not by any means agree. 
 
 To cut GAUGE GLASSES to length take a drill rod, sharpen 
 the end and turn it at right angles to rod, like cut, and harden 
 the end without drawing the temper. Be careful in hardening 
 not to get the point too hot, as its being so small it is liable to 
 be burned. 
 
 Every engineer will find this a handy tool. 
 
 When a glass is to be cut find the length, and with this tool 
 cut a ring around the inside of the glass and it will usually break 
 off square at that point at once. If it does not, a little heat 
 applied at that point will hasten, or if laid down a few minutes 
 it will crack off. 
 
 A glass cut on the outside, unless cut very deep with a file or 
 stone, is liable to crack anywhere. 
 
274 TWENTY YEARS WITH THE INDICATOR. 
 
 BABBITT METAL. 
 
 Nearly half a century ago Isaac Babbitt of Taunton, Mass.. originated 
 the alloy which has since been known as Babbitt Metal. It is highly valued 
 for its anti-friction qualities as compared with other metals. Isaac Babbitt 
 was a goldsmith by trade and made the first Britannia ware produced in this 
 country. He was honored with a gold medal for his discovery of his anti- 
 friction alloy, and was also presented with $20,000 by the Congress of the 
 United States. Below are several formulas for preparing Babbitt metal for 
 different uses : 
 
 WHITE ALLOY, OR BABBITT METAL. 
 
 A Copper 10 
 
 Tin 72 
 
 Antimony 18 
 
 100 
 This alloy is recommended for high-speed machinery journal boxes. 
 
 B Copper 1 
 
 Tin 48 
 
 Antimony 5 
 
 Lead.. 2 
 
 56 
 
 This alloy is more economical than the above and has a more greasy 
 touch than the first-named above, but is not so desirable for high speed. 
 
 C Lead 32 
 
 Zinc 20 
 
 Antimony 48 
 
 100 
 
 This alloy will resist a rapid friction. The zinc should be melted first, 
 then add the other metals. 
 
 D Lead 90 
 
 Antimony 100 
 
 This alloy is suitable for pillow blocks, agricultural or other slow work- 
 ing machinery. 
 
TWENTY YEAES WITH THE INDICATOR. 
 
 2 7S 
 
 [From Hamilton's Useful Information for Railroad Men.] 
 USEFUL NUMBERS FOR RAPID APPROXIMATION, 
 
 Feet 
 
 . . X .00019 
 
 = miles. 
 
 Yards 
 
 ..X -0006 
 
 = miles. 
 
 Links 
 
 ..X .22 
 
 = yards. 
 
 Links 
 
 ..X .66 
 
 =feei 
 
 Feet 
 
 , . X 1.5 
 
 links. 
 
 Square inches 
 
 . . X -007 
 
 = square feet. 
 
 Circular " . , 
 
 , . X .00546 
 
 it tt 
 
 Square feet 
 
 ..X .111 
 
 = " yards. 
 
 Acres 
 
 . . X4840. 
 
 a a 
 
 Square yards 
 
 ..X .0002066 acres. 
 
 Width in chains 
 
 ..X 8. 
 
 = " per mile. 
 
 Cubic feet 
 
 . . X .04 
 
 = cubic yards. 
 
 Cubic inches 
 
 . . X .00058 
 
 = " feet. 
 
 U. S. bushels 
 
 . . X .046 
 
 " yards. 
 
 a a 
 
 . . X 1.244 
 
 = " feet. 
 
 tt a 
 
 . . X2150.42 
 
 = " inches. 
 
 Cubic feet 
 
 . . X .8036 
 
 = U. S. bushels. 
 
 " inches 
 
 . . X .000466 
 
 a a 
 
 U. S. gallons 
 
 . . X .13368 
 
 = cubic feet. 
 
 a a 
 
 ..X 231. 
 
 = " inches. 
 
 Cubic feet 
 
 . . X 7.48 
 
 = U. S. gallons. 
 
 Cylindrical feet 
 
 . . X 5.878 
 
 tt tt 
 
 Cubic inches 
 
 . . X .004329 
 
 a a 
 
 Cylindrical inches 
 
 . . X .0034 
 
 tt it 
 
 Pounds 
 
 . . X .009 
 
 =cwt. (112 Ibs.) 
 
 Pounds 
 
 . . X .00045 
 
 =tons (2240 Ibs.) 
 
 Cubic feet water 
 
 . . X 62.5 
 
 =lbs. avoirdupoia 
 
 " inches " 
 
 . . X .03617 
 
 tt tt 
 
 Cylindrical foot of water. . . . 
 
 . . X 49.1 
 
 .. tt 
 
 Cylindrical inches of water. . . 
 
 . . X .02842 
 
 .. tt 
 
 U. S. gallons of water 
 
 . . : 13.44 
 
 =cwt. (112 Ibs.) 
 
 U. S. gallons of water 
 
 ..+ 268.8 
 
 tons. 
 
 Cubic feet water 
 
 . . : 1.8 
 
 =cwt. (112 Ibs.) 
 
 tt it tt 
 
 . . 35.88 
 
 =tons. 
 
 Cylindrical foot of water 
 
 . . X 5.875 
 
 =U. S. gallons. 
 
 Column of water, 12" high ; 1 
 
 inch diameter 
 
 =34 pounds. 
 
 183,346 circular inches 
 
 
 = 1 square foot. 
 
 2,200 cylindrical inches 
 
 
 = 1 cubic " k 
 
 French metres 
 
 . . X 3.281 
 
 =feet. 
 
 Kilogrammes 
 
 . . X 2.205 
 
 = avoirdupois Ibs, 
 
 Grammes 
 
 . . X .0022 
 
 tt tt 
 
276 TWENTY YEARS WITH THE INDICATOR. 
 
 To write upon terra-cotta tablets, dip the clay tablet in milk, with a few 
 drops of acid added, and then dry. When this is done you can write upon it 
 as easily as upon paper. 
 
 THE PROPERTIES OF SATURATED STEAM. 
 
 In the tables which follow, steam is considered from M. Regnault' B 
 results, and " total heat " is from the Fahrenheit zero. 
 
 The bases of all his results are, that the saturated steam maintains rela- 
 tively density, temperature, and pressure unchangeably to each other, and it 
 naturally follows that if one of these properties are for any cause changed, 
 that the others also change in some fixed ratio, or that each of the others 
 pass through relative changes in proportion, so that all the factors change 
 proportionately, and the basis remains the same or unchanged. 
 
 In specific heat, water exceeds any other substance known, and the 
 specific heat of any body is the amount of heat required to raise its 
 temperature 1, taking the amount of heat required to raise the tem- 
 perature of water 1 (an equal weight) as the unit. The specific heat 
 of superheated steam, as stated by M. Regnault, is .48, while satu- 
 rated steam is .305 ; and the same authority states, that as saturated 
 steam is always at its dew point, and, if its density is maintained, all 
 the loss of heat encountered must be supplied by its partial condensation, 
 and, while it does not contain water necessarily, its temperature cannot be 
 any higher than that of the water from which it was generated. It has, 
 until recently, been supposed that the specific heat of saturated steam was 
 nothing, as it did not require an additional amount of heat to raise its 
 temperature, and it was also supposed that the latent heat gave the increase 
 of temperature ; but M. Regnault has determined differently, and that 
 an addition is required of .304 to its total heat to raise the temperature one 
 degree. See Tables I, II, HI, IV and V. 
 
8 
 
 
 1.0* 
 
 
 S 
 
 . 
 
 
 
 5 
 
 10 ^ COOt 1-4 1-4 
 
 05 Tl< SO (N C T 
 
 <N"*OCO-<f T-tt- 0510 i- TH 
 
 S 05 
 

 
 
 o o <oi>E^i^^-t^-t.--t- ^-00000000 300006 5o 
 
 co eo o o t t- z> t- oo oo oo oo os o o o o o o o 
 
TWENTY YEARS WITH THE INDICATOR 
 
 279 
 
 III. 
 
 HYPERBOLIC LOGARITHMS. 
 
 No. 
 
 Log. 
 
 No. 
 
 Log. 
 
 No. 
 
 Log. 
 
 No. 
 
 Log. 
 
 No. 
 
 Log. 
 
 No. 
 
 """ 
 
 Log. 
 
 1.05. 
 
 .049 
 
 2.4 
 
 .875 
 
 3.75 
 
 1.322 
 
 5.15 
 
 1.639 
 
 6.5 
 
 1.872 
 
 7.85 
 
 2.061 
 
 1.1 
 
 .095 
 
 2.45 
 
 .896 
 
 3.8 
 
 1.335 
 
 5.2 
 
 1.649 
 
 6.55 
 
 1.879 
 
 7.9 
 
 2 067 
 
 1.15 
 
 .14 
 
 2.5 
 
 .916 
 
 3.85 
 
 1.348 
 
 1 5.25 
 
 1.658 
 
 6.6 
 
 1.887 
 
 7.95 
 
 2.073 
 
 1.2 
 
 .182 
 
 2.55 
 
 .936 
 
 3.9 
 
 1.361 
 
 I 5.3 
 
 1.668 
 
 6.65 
 
 1.895 
 
 8. 
 
 2.079 
 
 1.25 
 
 .223 
 
 2.6 
 
 .956 
 
 3.95 
 
 1.374 
 
 5.33 
 
 1.673 
 
 6.66 
 
 1.896 
 
 8.05 
 
 2.086 
 
 1.3 
 
 .262 
 
 2.65 
 
 .975 
 
 4. 
 
 1.386 
 
 5.35 
 
 1.677 
 
 6.7 
 
 1.902 
 
 8.1 
 
 2.092 
 
 1.33 
 
 .285 
 
 2.66 
 
 .978 
 
 4.05 
 
 1.399 
 
 5 4 
 
 1.686 
 
 6.75 
 
 1.91 
 
 8.15 
 
 2.098 
 
 1.35 
 
 .3 
 
 2.7 
 
 .993 
 
 4.1 
 
 1.411 
 
 5.45 
 
 1.696 
 
 6.8 
 
 1.917 
 
 8.2 
 
 2.104 
 
 1.4 
 
 .336 
 
 2.75 
 
 .012 
 
 4.15 
 
 1.423 
 
 5.5 
 
 1.705 
 
 6.85 
 
 1.924 
 
 8.25 
 
 2.11 
 
 1.45 
 
 .372 
 
 2.8 
 
 .03 
 
 4.2 
 
 .435 
 
 5.55 
 
 1.714 
 
 6.9 
 
 1.931 
 
 8.3 
 
 2.116 
 
 1.5 
 
 .405 
 
 2.85 
 
 .047 
 
 4.25 
 
 .447 
 
 5.6 
 
 1.723 
 
 6.95 
 
 1.939 
 
 8.33 
 
 2.119 
 
 1.55 
 
 .438 
 
 2.9 
 
 .065 
 
 4.3 
 
 .459 
 
 5.65 
 
 1.732 
 
 7. 
 
 1.946 
 
 8.35 
 
 2.122 
 
 1.6 
 
 .47 
 
 2.95 
 
 .082 
 
 4.33 
 
 .465 
 
 5.66 
 
 1.733 
 
 7.05 
 
 1.953 
 
 8.4 
 
 2.128 
 
 1.65 
 
 .5 
 
 3. 
 
 .099 
 
 4.35 
 
 .47 
 
 5.7 
 
 1.74 
 
 7.1 
 
 1.96 
 
 8.45 
 
 2.134 
 
 1.66 
 
 .506 
 
 3.05 
 
 .115 
 
 4.4 
 
 .482 
 
 5.75 
 
 1.749 
 
 7.15 
 
 1.967 
 
 8.5 
 
 2.14 
 
 1.7 
 
 .531 
 
 3.1 
 
 .131 
 
 4.45 
 
 .493 
 
 5.8 
 
 1.758 
 
 7.2 
 
 1.974 
 
 8.55 
 
 2.146 
 
 1.75 
 
 .56 
 
 3.15 
 
 .147 
 
 4.5 
 
 .504 
 
 5.85 
 
 1.766 
 
 7.25 
 
 1.981 
 
 8.6 
 
 2.152 
 
 1.8 
 
 .588 
 
 3.2 
 
 .163 
 
 4.55 
 
 .515 
 
 5.9 
 
 1.775 
 
 7.3 
 
 1.988 
 
 8.65 
 
 2.158 
 
 1.85 
 
 .612 
 
 3.25 
 
 .179 
 
 4.6 
 
 .526 
 
 5.95 
 
 1.783 
 
 7.38 
 
 1.991 
 
 8.66 
 
 2.159 
 
 1.9 
 
 .642 
 
 3.3 
 
 .194 
 
 4.65 
 
 .537 
 
 6. 
 
 1.792 
 
 7.35 
 
 1.995 
 
 8.7 
 
 2.163 
 
 1.95 
 
 .668 
 
 3.33 
 
 .202 
 
 4.66 
 
 .54 
 
 6.05 
 
 1.8 
 
 7.4 
 
 2.001 
 
 8.75 
 
 2.169 
 
 2. 
 
 .693 
 
 3.35 
 
 .209 
 
 4.7 
 
 .548 
 
 6.1 
 
 1.808 
 
 7.45 
 
 2.008 
 
 8 8 
 
 2.175 
 
 2.5 
 
 .718 
 
 3.4 
 
 .224 
 
 4.75 
 
 .558 
 
 6.15 
 
 1.816 
 
 7.5 
 
 2.015 
 
 8.85 
 
 2.18 
 
 2.1 
 
 .742 
 
 3.45 
 
 .238 
 
 4.8 
 
 .569 
 
 6.2 
 
 1.824 
 
 7.55 
 
 2.022 
 
 8.9 
 
 2.186 
 
 2.15 
 
 .765 
 
 3.5 
 
 .253 
 
 4.85 
 
 .579 
 
 6.25 
 
 1.833 
 
 7.6 
 
 2.028 
 
 8.95 
 
 2.192 
 
 2.2 
 
 .788 
 
 3.55 
 
 .267 
 
 4.9 
 
 .589 
 
 6.3 
 
 1.841 
 
 7.65 
 
 2.035 
 
 
 
 2.25 
 
 .811 
 
 3.6 
 
 .281 
 
 4.95 
 
 .599 
 
 6.33 
 
 1.845 
 
 7.66 
 
 2.036 
 
 
 
 2.3 
 
 .833 
 
 3.65 
 
 .295 
 
 5. 
 
 .609 
 
 6.35 
 
 1.848 
 
 7.7 
 
 2.041 
 
 
 
 2.33 
 
 .845 
 
 8.66 
 
 .297 
 
 5.05 
 
 .619 
 
 6.4 
 
 1.856 
 
 7.75 
 
 2.048 
 
 
 
 2.35 
 
 .854 
 
 3.7 
 
 .308 
 
 5.1 
 
 .629 
 
 6.45 
 
 1.864 
 
 7.8 
 
 2.054 
 
 
 
 EFFECT OF EXPANSION WITH EQUAL VOLUMES OF STEAM. 
 
 The theoretical economy of using steam expansion is as follows. A like volume of steam being 
 expended in each case, and expanded to fill the increased spaces. 
 
 Point of 
 Cutting Off. 
 
 Expansion 
 Number. 
 
 Mean 
 Pressure 
 of Steam. 
 
 Gain 
 Per Cent, 
 in Power. 
 
 Point of 
 Cutting Off. 
 
 Expansion 
 Number. 
 
 Mean 
 Pressure 
 of Steam. 
 
 Gain 
 Per Cent, 
 in Power. 
 
 .1 
 
 10. 
 
 3.302 
 
 230. 
 
 .5 
 
 2. 
 
 .693 
 
 69.3 
 
 .125 
 
 8. 
 
 3.079 
 
 208. 
 
 .6 
 
 1.66 
 
 .507 
 
 50.7 
 
 .166 
 
 6. 
 
 2.791 
 
 179. 
 
 vis 
 
 1.6 
 
 .47 
 
 47. 
 
 .2 
 
 5. 
 
 2.609 
 
 161. 
 
 .666 
 
 .5 
 
 .405 
 
 40.5 
 
 .25 
 
 4. 
 
 2.386 
 
 139. 
 
 .7 
 
 .42 
 
 .351 
 
 35.1 
 
 .3 
 
 3.33 
 
 2.203 
 
 120. 
 
 .75 
 
 .33 
 
 .285 
 
 22.3 
 
 .333 
 
 3. 
 
 2.099 
 
 110. 
 
 .8 
 
 .25 
 
 1.223 
 
 20.5 
 
 .375 
 
 2.66 
 
 1.978 
 
 97.8 
 
 .875 
 
 .143 
 
 1.131 
 
 13.1 
 
 .4 
 
 2.5 
 
 1.916 
 
 91.6 
 
 .9 
 
 .11 
 
 1.104 
 
 10.4 
 
 In this illustration no deductions are made for a reduction of the temperature of the steam while 
 expanding or for loss by back pressure. 
 
 The same relative advantage follows in expansion as above given, whatever may be the initial 
 pressure of the steam. 
 
28o 
 
 TWENTY YJEAES WITH THE INDICATOR. 
 
 FRACTIONS OF INCH EXPRESSED IN DECIMALS. 
 
 
 Decimals. 
 
 1-64 
 
 = .015625 
 
 2-64= 1-32 
 
 = .03125 
 
 3-64 
 
 = .046875 
 
 4-64= 2-32= 1-16 
 
 = .0625 
 
 6-64= 3-32 
 
 = .09375 
 
 8-64= 4-32= 2-16=1-8 
 
 = .125 
 
 10-64= 5-32 
 
 = .15625 
 
 12-64= 6-32= 3-16 
 
 = .1875 
 
 14-64= 7-32 
 
 = .21875 
 
 16-64= 8-32= 4-16 = 2-8=1-4 
 
 = .25 
 
 18-64= 9-32 
 
 = .28125 
 
 20-64=10-32= 5-16 
 
 = .3125 
 
 22-64=11-32 
 
 - .34375 
 
 24-64=12-32= 6-16=3-8 
 
 = .375 
 
 26-64=13-32 
 
 = .40625 
 
 28-64=14-32= 7-16 
 
 = .4375 
 
 30-64=15-32 
 
 = .46875 
 
 32-64=16-32= 8-16=4-8=2-4=1-2= .5 
 
 34-64=17-32 
 
 = .53125 
 
 36-64=18-32= 9-16 
 
 = .5625 
 
 38-64=19-32 
 
 = .59375 
 
 40-64=20-32=10-16 = 5-8 
 
 = .625 
 
 42-64=21-32 
 
 = .65625 
 
 44-64=22-32=11-16 
 
 = .6875 
 
 46-64=23-32 
 
 = .71875 
 
 48-64 = 24-32 = 1 2-16 = 6-8=3-4 
 
 = .75 
 
 50-64=25-32 
 
 = .78125 
 
 52-64=26-32=13-16 
 
 = .8125 
 
 54-64=27-32 
 
 = .84375 
 
 56-64 = 28-32 = 14-16 = 7-8 
 
 = .875 
 
 58-64=29-32 
 
 = .90625 
 
 60-64=30-32=15-16 
 
 = .9375 
 
 62-64=31-32 
 
 = .96875 
 
 64-64=32-32=16-16=8-8=4-4=2-2=1.00000 
 
THE AMERICAN 
 Thompson Improved Indicator 
 
 Complete with Fittings 
 
 281 
 
THE AMERICAN 
 Combined Pressure and Recording Gauge 
 
 282 
 
THE AMERICAN 
 Dead Weight Gauge Tester 
 
 Complete with Fittings 
 
BONNER PORTLAND 
 
 THE AMERICAN 
 
 Gauge Board or Frame 
 
 284 
 
THE AMERICAN 
 
 Special Pop Safety Valve 
 
 285 
 
THE AMERICAN 
 SPECIALTIES 
 
 GAUGES 
 
 BOURDON Pressure, Vacuum, Compound, Combination, Am- 
 monia, Hydraulic, Illuminated Dial, Pyrometer, Automobile, Test, Farm 
 Engine. Altitude, Recording. LANE DOUBLE SPRING Locomo- 
 tive and Farm Engine. DUPLEX Air Brake, Automobile, Recording 
 and Combined Pressure and Recording. 
 
 DEAD WEIGHT GAUGE TESTER. 
 
 VALVES 
 
 POP SAFETY Stationary, Marine, Portable, House Heater, 
 Automobile. 
 
 RELIEF Cylinder, Underwriter, Water, Hydraulic. 
 
 INDICATORS 
 
 American Thompson Improved. 
 
 American Thompson Improved with Detent Motion. 
 
 American Exposed Spring Indicator. 
 
 American Ideal Reducing Wheel. 
 
 American Amsler's Polar Planimeter. 
 
 WHISTLES 
 
 Plain Steam and Long Bell, Single Bell Chime. 
 Single Bell Quartet Chime. 
 
 Ellison's Throttling Calorimeter, Test Pumps, Counters Round 
 and Square Case, Clocks Marine and Locomotive, Water Gauges, 
 Gauge Cocks, Ellison's Draft Gauges and other specialties. 
 
 * 
 Manufactured Solely by 
 
 AMERICAN STEAM GAUGE AND VALVE 
 MANUFACTURING CO. 
 
 220CAMDEN STREET, BOSTON, MASS. 
 New York Atlanta Chicago 
 
 286 
 

 UNIVERSITY OF CALIFORNIA LIBRARY 
 BERKELEY 
 
 Return to desk from which borrowed. 
 This book is DUE on the last date stamped below. 
 
 ~ 
 
 DEC 
 
 pCt 24 194< 
 
 OCT2? 1950 
 i ~ 1951 
 
 L-ZC28 1950 
 
 LD 21-100m-9,'47(A5702sl6)476 
 
 

 274759 
 
 
 ' Engineering 
 Library 
 
 UNIVERSITY OF CALIFORNIA LIBRARY