Class. 
 Book- 
 
 COPYRIGHT DEPOSIT 
 
^ \ 
 
 AIDS 
 
 Engineers' Examinations 
 
 QUESTIONS AND ANSWERS. 
 
 y 
 
A 
 
 Copyright by 
 
 THEO. AUDEL & CO., New York City. 
 
 Sept., 1894 and Sept., 1901 
 
 T 
 
K 
 
 This work is Dedicated ro 
 VICTOR HAWKINS 
 
 AT WHOSE REQUEST IT HAS BEEN COMPILED, 
 
 ^ 7^ 
 
/ 
 
 WASHINGTON MULLIN. 
 See page 203. 
 
 ^ 
 
 •7 
 

 TO 
 
 Engineers' Examinations. 
 
 PREPARED FOR 
 
 APPLICANTS OF ALL GRADES, 
 
 WITH 
 
 QUESTIONS AND ANSWERS. 
 
 A Summav'tf of tlie Principles and Practice 
 of Steam Engineering, 
 
 By N. HAWKINS, M. E., 
 
 Author: New Catechism of the Steam Engine: Hand Booh 
 
 of Calculations for Engineers; Instructions for the 
 
 Boiler Room ; New Catechism of Electricity, etc. 
 
 New York: 
 Theo. Audel & Co., 63 Fifth Ave. 
 
 X 
 
 1902. i ^ ' 
 
-^'/^/Ji 
 
z 
 
 \ 
 
 INTRODUCTION. 
 
 Chere are three parties to an engineer's licenfir 
 
 First. The Applicant. 
 
 Second The Public. 
 
 Third The Examiners, or examining board of engineers. 
 
 To the applicant the period cf an examination is a season 
 of nervous dread and the utmost fitness does not always 
 remove the feeling of anxiety. 
 
 Men often operate steam plants satisfactorily who can- 
 not tell how they do it, and a thoroughly practical engineer 
 may make a very poor showing when questioned by an 
 examiner. 
 
 it is sometimes still worse when modest applicants 
 are required to write their experience, for in the hands of 
 many men the pen is an awkward tool ; hence a very large 
 margin is allowed to men who can demonstrate that they 
 have had the necessary practical experience, even though 
 they may not be able to answer questions oif -hand ; and those 
 who have become " rattled " under the unusual catechising. 
 are frequently kindly advised by the examiner to " come and 
 try a^ain." 
 
 V 
 
 K 
 
 V 
 
z 
 
 £NTRODUCnOJS. 
 
 WTiile the tendency in all lines of engineering is toward 
 thorough familiarity with principles, there are stiU good 
 chances for safe men, who are comparatively unlearned, to 
 acquire experience by actual work in engine rooms. 
 
 The relation of the public, to the issue of an engineer's 
 license, is the same as that in which it stands to the issue of 
 druggists and drug-clerk Ucenses ; that is, the fundamental 
 right to protect itself from the criminal ignorance of un- 
 worthy pretenders in handling or dispensing dangerous ma- 
 terials. 
 
 The community possesses the privilege of passing upon 
 the qualifications of its citizens who propose to manage 
 and control machinery or chemicals which, used without 
 experience or good natural judgment, are liable to cause 
 suffering and loss to innocent persona. 
 
 No one now disputes this fundamental principle of common 
 law ; and it is a notable fact that the more competent a man 
 is for the performance of an engineer's duties, the more he 
 desires an honest administration of the laws regarding the 
 subject, and a safe standard of qualification- 
 Relating to the office of an Examining Engineer it may be 
 said that the position is no sinecure, for he should be 
 thoroughly qualified to examine and pass on candidates, so 
 that none but sober, competent and careful men are passed. 
 As examinations must, perforce, be conducted by practical 
 engineers, it follows that upon engineers, as a class and pro 
 fession, depend their own standing in the community. If 
 the Examiner is a high-toned, sober, intelligent man, in the 
 course of time the men he passes upon, and to whom he 
 awards licenses, will be very nearly up to his own standard as 
 
 K 7 
 
/- 
 
 X 
 
 INTBODUCTION 
 
 a man. It would be worthy of interest to know the history, 
 education and experience of, say, one hundred of the exam- 
 ining engineers of the country ; for these men, as models, the 
 thousands of men who come under their contact, will cer- 
 tainly emulate and approach while never passing their 
 standard of excellence; hence the future welfare of steam 
 engineering as a profession and the money income of its 
 members depend almost wholly upon the Examiners. 
 
 The test to which Examiners themselves are put before 
 receiving their appointments is very se'^<^re. and to have held 
 this appointment is a life-long honor. 
 
 In a recent single year's report of the New York City 
 Steam Boiler Inspection and Engineer Bureau, there were 
 one thousand one hundred and sixteen examinations of new 
 applicants for engineer's licenses, of which no less than five 
 hundred and thirty were found incompetent and certificates 
 refused. 
 
 Of the five hundred and eighty-six successful applicants, 
 there passed; 
 
 On the first examination 434 
 
 On the second examination 126 
 
 On tlie third examination. . . 23 
 
 On the fourth examination 8 
 
 586 
 
 la the same year there were: 
 
 Certificates, renewed 4. 597 
 
 " transferred I,3d3 
 
 New certificates granted 586 
 
 Making the total number in force. . 6,566 
 
 \: 
 
 7 
 
/ 
 
 mTRODVVTlOIs. 
 
 These six thousand five hundred and sixty -six certificatee 
 were divided thus 
 
 Certificates of the 1st class 1, 83^ 
 
 2d class 1,49b 
 
 3d class, a. 409 
 
 Vhe department engineers. 196 
 
 Permits for boilers only ............ 135 
 
 6.566 
 
 and in ihe same year there were eight thousand four 
 Hundred and thirty eight inspections made of steam boilers. 
 
 The sum of two dollars for each certificate, amounting to 
 $13,724.00 was collected and paid to the Treasurer of the 
 Police Pension Fund in accordance with the provisions of 
 Chap. 437, Laws of 1885. 
 
 In New York City each boiler is numbered in tlie Records 
 at Headquarters ; each Engineer's certificate is likewise num- 
 bered, and a heavy fine is imposed for misusing the papers 
 for another's benefit ; and in case of the loss even of the 
 papers the fact must be immediately reported at the office of 
 the Examiner, and a fine may be imposed for the carelessness 
 which resulted in the loss of the certificate. 
 
 It will tlius appear that each license applies to a special 
 steam-plant, of which a full description is kept in the files. 
 When an engineer changes his position he must have his 
 certificate "transferred." By this it will be seen that an 
 applicant must first secure his position ; and then his license 
 — if he is found worthy — is usually granted upon the written 
 request of the owner of the steam-plant, who has previously 
 engaged him, ajid fijted the details of service and compensa 
 
 tiOTl 
 
 ^^ / 
 
/ \ 
 
 INTRODUCTION, 
 
 The certificates are for one year, and on each are printed 
 the following rules : 
 
 " Holders of certificates must apply to the officer in com 
 mand of the Sanitary Company for re-examination and re 
 aewal of certificates on the dates of the expiration of the 
 certificate. This date of expiration will be found printed on 
 the face of the certificate. 
 
 The certificate allows the person named to take charge of 
 and operate the steam-boiler mentioned, bid no other, and 
 will be revoked on proo^ of uegliseuce or insobriety." 
 
 V 
 
 -7 
 
 / 
 
MIDS 
 
 TO 
 
 ENGINEERS' EXAMINATIONS. 
 
 The necessary qualifications to secure a license are nearly 
 in the following order : 
 
 1st. — Character or general fitness for the trust. 
 
 2d. — Knowledge and experience relating to the steam 
 generator. 
 
 3d. — Skill in the running of the steam-engine and other 
 machines. 
 
 Before the issue or the refusal of a license to an applicant 
 he is examined personally, and alone, by one of the Board, 
 all of whom are practical engineers ; and there is no stated 
 list of questions either oral or written. 
 
 If a candidate show^s by his answers that he is familiar, 
 through actual experience with his duties, and not coached 
 by some one for the mere purpose of obtaining a license, be 
 is entitled to his papers. 
 
 Relating to character qualification, it may be said that 
 as the engineer is to be in charge with an almost independ 
 
li /SNOINWEBS' lijJi^MlJ\A.TIOJSli. 
 
 ent trust of property and life, the Examiner will, before any- 
 thing else, seek to ascertain something of the habits and 
 moral principles of the applicant. No man, if it is known, 
 who ever yields to intoxication, and no one who is a con- 
 victed embezzler, will be granted a license ; without question 
 the indefinable marks of an honest man go very far towards 
 securing to him his papers. 
 
 The reliable engineer is nearly always a man of thoughtf ui 
 dignity of manners, as naturally becomes habitual to one under 
 an vmceasing weight of responsibility, involving so much; 
 this outward evidence of inward qualities is rightly most 
 tavorable to an applicant. 
 
 Character is what a man really is, and a good character 
 implies many virtues, such as truthfulness, courage and cool- 
 ness under sudden danger, a habit of tidiness in person and 
 dress, strict honesty and large-mindedness ; all these are to 
 be expected from an applicant for an engineer's papers. 
 
 So important is this qualification — of good character — con 
 fiidered, that there are printed on each of the seven thonsand 
 licenses issued by New York City the following. 
 
 Chapter 643, Laws of 1886. •' When, on examination of 
 an applicant, it appears to the satisfaction of the Engineers 
 that he lacks natural capacity, or mechanicel skUl, knowl- 
 edge or experience; or is unfitted by habits of insobriety to 
 perform the required duties in a manner consistent with 
 safety of life, a certificate of qualification will be denied. 
 Renewals of certificates will be refused, and certificates wiD 
 be revoked on proof of like deficiencies." 
 
 For many reasons a good character is the first requisite far 
 the STuarlDs; of a license, nomine even before sJdU souj 
 
ENOTXEERS' EXAMINATIONS, 15 
 
 knowledge of the business. It is on account of its relative 
 importance that applicants are first required to give an ac- 
 count of their experience in the practical duties of engineer, 
 macliinist or firemen. 
 
 As to the general fitness of the applicant it may be said 
 chat age implying a certain length of experience is necessary ; 
 svhile on the other, extreme age, even with great skillful 
 aeps if accompanied by bodily weakness, is a bar to passing, 
 Defective eyesight, an evidence of extreme nervousness, and 
 certain bo<lily defects, are very potent reasons for withhold 
 ing consent 
 
 Secondly, the examiner will proceed to ascertain the 
 applicant's kno vledge of the steam generator. No applicant 
 wanting in praccical experience in the care and management 
 of the steam boiler will be permitted to pass. If there were no 
 liabU ity of steam explosions there would be no need of issuing 
 licenses in stationary engineering service any more than 
 for a license to run wood or iron working machinery, pile 
 drivers, or the thousand and one machines used in modern 
 industry for example, no license is required to run a water- 
 mill liowever large, unless it has a steam boiler on tht= 
 prewises 
 
 Accidents m steam plants, like the bursting of fly-wheels 
 and breaking of cylinder -heads, even if accompanied by in 
 jury and loss of life, cause no uneasiness in the public mind, 
 and carry no personal discredit to the Examiner; but. if a 
 license is granted to an unworthy person, and an explosion 
 of a steam boiler occurs, causing personal injury or loss of 
 life, then the public, through its Coroner's or other juries will 
 
le ENGINEERS' EXAMINATIONS. 
 
 blame the Examiner for being remiss in guarding its safety, 
 as well as the person in direct charge. Hence, the sharpest 
 questionings come in reference to the steam boiler. 
 
 While the first element of stress is laid upon character, 
 the second is properly put upon the knowledge of the steam 
 generator, and the greater portion of this book of ' ' aids " 
 will be devoted to the problems relating to its construction, 
 safety and management. 
 
 Third will come all these questions relating to the steam-sn- 
 gine, pumps, piping and general knowledge, which go to prove 
 that the applicant is really an engineer (that is, an ingenious 
 person), capable of the position of trust to which he aspires. 
 
 So very different in responsibility are the positions required 
 to be filled by the engineer that it is almost always a matter 
 of individual judgment with the examiner as to the fitness 
 of the man for the place ; and in forming this judgment 
 and deciding aright both the discernment and skUl of the 
 examining engineer are exhibited. 
 
 In the latter part of this work will be found several ex- 
 tracts from city and United States laws, relating to engineer's 
 licenses and examinations. These will, doubtless, form 
 models for other parts of the country, as yet without laws 
 bearing on the subject, as they, one by one, adopt the systeui 
 of protection found so useful, where it has been tested 
 
CLASSIFICATION OF KNOWLEDGE. 17 
 
 CLASSIFICATION OF KNOWLEDGE THE KEY 
 TO SUCCESS. 
 
 " When a 'mizn''s knowledge is not in order the more he has of it the 
 ■77orse he is o^."— OiD Proverb. 
 
 This old saying conveys the strange truth that sometimes 
 the mors a man knows the more useless is what he knows. 
 It is. true notwithstanding its strangeness, and it is true 
 especially in practical steam engineering. 
 
 On a certain corner in the Bowery of New York City may 
 be seen a store window packed full of all kinds of cutlery — 
 razors, corkscrews, butcher knives, files, screw drivers, 
 pistols, hammers, boxes of drawing tools and a hundred 
 other things in the hardware line. These are all in one jum- 
 bled mass in indescribable confusion and are an emblem of 
 the disorder in the mind of an unapt, blundering, unskillful 
 man in the engine or boiler room. He has the knowledge, 
 perhaps, but it is never available when needed. 
 
 Now, on Park Row, a little south, there is a regular hard- 
 w^are store with a stock of goods a hundred times the variety 
 and a thousand times as large as that in the Bowery and yet 
 scores of men and many teams serve hundreds of customers 
 every day ancf block the sidewalks with the incoming and 
 outgoing loads of their ware, handled in the big many 
 
18 CLASSIFICATION OF KNOWLEDGE. 
 
 storied building and all without confusion, loss or hurry. 
 This is also a symbol of another kind of man who has his 
 wide and extensive knowledge well in hand for ready use, 
 who easily may assume with credit the position of cliief 
 engineer. 
 
 What is the key to success in the management of a steam 
 plant and of personal advancement ? It consists in the 
 scientific or orderly arrangement of the various knowledge 
 required to make the experienced engineer. 
 
 Not only the chief but the assistant engineer, the oiler and 
 the fireman should strive towards this due classification — as 
 soon as a fact is acquired let it be stored away in its proper 
 place in the mind. Facts about steam with the steam 
 (mental) department — facts about the engine in the engine 
 (mental) department ; facts about piping and valves with the 
 pipe and valve (mental) department, etc. , etc. 
 
 In this way the mind and memory are filled with available 
 knov.dedge like a well written book with a reference index. 
 
 For instance all the various items of information relating 
 to the physical properties of steam should be grouped together 
 in the engineer's mind, or he should know where and when 
 to lay his hands upon needed information relating to this 
 subject. Example: There is a table of steam properties 
 called Regnault's Tables, which show the temperature of 
 steam at the different pressures, the volume per pound in 
 cubic feet at the different temperatures, etc. Now it is not 
 necessary to carry all the figures in one's ihtnd, it is only 
 necessary to know of the existence of the Tables, where they 
 
CLASSIFICATION OF KNOWLEDGE. 19 
 
 are to be found — in what book and in what library, and finally 
 to accurately apply the figures to the problem to be decided. 
 
 To know these and other fundamental laws is a long step 
 in the science of steam engineering and the remuneration is 
 large to the man who knows and can use his knowledge. 
 
 The rudiments of steam engineering can be acquired by 
 about two years of constant application, and close observation, 
 by a person who has a liking for the work. A person w^ho 
 does not like to perform the duties required will never acquire 
 "full competency" for the duties required of a chief engi 
 neer, for the reason that he will not have the opportunity. 
 
 A system of education that tends to broaden the mind and 
 thus render it capable of dealing confidently with large 
 questions is not only most likely to make the engineer edu- 
 cated uiider it more respected by those with whom he comes 
 into contact in professional life, but it gives him a wider 
 range of opportunities. 
 
 The immense magnitude of modern steam plants and their 
 combination of Steam, Electricity, Refrigeration, Transpor- 
 tation, etc. , calls for first class men to manage the complex 
 machinery. 
 
 This theme is a difficult although necessary one, and 
 etdvice relating to it may be summed up thus — 
 
 First. Do not "lumber " the mind with useless matters. 
 
 Second. Be sure of the truth of each single fact. 
 
 Third. Store the fact or item of information away in the 
 mind with other kindred items relating to the same depart 
 naent of engineering. 
 
20 CLASSIFICATION OF KNOWLEDGE, 
 
 To make the most of oneself is a problem, which has been 
 answered by the word concentration. Keep close to one line 
 of advancement and be content to be ignorant of some things 
 in order to know thoroughly some others, The path being 
 chosen, then let the advance be persistent and unceasing. It 
 was thus that Stephenson produced such results in locomo 
 tion, and Watt such wonders with the steam engine. 
 
 This persistent industry is not irksome. It carries its own 
 reward, and the resvilts are definite and sure. 
 
 " One step and then another. 
 
 And the longest walk is ended ; 
 One stitch and then another. 
 
 And the largest rent is mended. 
 One brick upon another. 
 
 And the highest wall is made : 
 One flake upon another. 
 
 And the deepest snow is laid. 
 
THE STEAM BOILER. 21 
 
 THE STEAM BOILER. 
 
 WMle the shapes and forms in which steam generators 
 have been constructed are many, they all agree in one point 
 — they are closed vessels strongly made so as to withstand an 
 internal pressure of considerable force. 
 
 In engineering terms this force is called the steam press- 
 ure and it varies from 5 to 300 lbs. per square inch. It is the 
 first rule in the design of steam boilers to provide against 
 this varying internal force. 
 
 While the sphere is the stromjest form of vessel to resist 
 internal pressure, there are many practical reasons which 
 prevent its being used for the purpose. Next to the sphere 
 the cylindrical form is the simplest and strongest, and is now 
 universally adopted. 
 
 The steam boiler has two essential parts, the furnace 
 which contains the fuel to be burnt and the boiler containing 
 the water to be evaporated. Within the boiler there nmst be 
 steam-room as well as water space — outside there must be 
 heating surface and a chimney or other apparatus to convej' 
 away the waste products of combustion. 
 
22 ENOINEEBS' EXAMJ]VATLL\NB 
 
 Questions and Answers Relating to Materials 
 for Boilers. 
 
 Ques. What is the meaning of Tensile strength when ap 
 plied to rivets, braces and boiler plates ? 
 
 Ans. It is that amount of force— usually ex- 
 pressed in pounds — which, steadily and slowly ap- 
 plied in a, straight line, just overcomes the cohesion 
 of the particles and pulls it into separate parts 
 
 Ques. What is the meaning of shearing strength ? 
 
 Ans. It is that amount of force — usually ex- 
 pressed in pounds — which, if steadily and slowly 
 applied to the rivet, at right angles to its axis, causes 
 it to separate in parts, which slide over each other. 
 This separation is nearly always at right angles, and 
 in common language is called "shearing off the 
 the rivets." 
 
 (Jues. What is the meaning of elastic limit ? 
 
 Ans. This is the point to which steel or iron can 
 be stretched out, and from which the metal will 
 return to its original position. When steel is pulled 
 beyond its limit of elasticity, it does not return to 
 its old place ; the "bagging" of a burnt sheet over 
 the fire is an example of the plate having been 
 Stretched beyond iis limit of return. 
 
QUESTIONS AND ANSWERS. *23 
 
 Ques. What is the meaning of ductile ? 
 
 Ans. The material is " ductile/' when it can be 
 extended by a pulling or tensile force and remain 
 extended after the force is removed ; the greater 
 the permanent extension the more ductile the ma- 
 terial. 
 
 (Jues What is the meaning of " tough " when applied to 
 iron or steel ? 
 
 Ans. The material is said to be tough when it 
 can be bent first in one direction and then the op- 
 posite direction without breaking or cracking. The 
 greater the angles it bends through (coupled with the 
 number of times it bends) the tougher it is. 
 
 Ques. What is the meaning of malleable ? 
 
 Ans. This is the term applied to iron or steel 
 when it can be extended by hammering or rolling 
 without cracking and remain extended ; the more it 
 can be extended without fracturing, the more malle- 
 able it is. 
 
 Ques. What is weldable iron or steel ? 
 
 Ans. This is the term which is applied to the 
 material if it can be united when hot by hammering 
 or pressing together the heated parts. The nearer 
 the properties of the metal after being welded are 
 to what they were before being heated and welded, 
 the more weldable it is. 
 
 Ques. What does homogeneous mean when applied to 
 boiler plates ? 
 
84 ENOmEEBS' EXAMINATIONS. 
 
 Ans. This word describes material of the same 
 structure and nature ; where the grain or fibre of 
 the plate is the same in every direction. 
 
 Ques. What is the meaning of cold-short iron or steel ? 
 
 Ans. This is a name given to the material when 
 it cannot be rolled or hammered, or be bent when 
 cold without cracking; such a material can be worked 
 or bent when at a great heat, but not at any tem- 
 perature greater than that assigned to dull-red. 
 
 Ques. What is the meaning of " hot -short ?" 
 
 Ans. This is when the material cannot be easily 
 worked under the hammer, or by rolling at a red- 
 heat, at any temperature which is assigned to a red 
 heat, without fracturing or cracking, such a material 
 may be worked or bent at a less heat. 
 
 Ques. What is the meaning of elongation of metals ? 
 
 Ans. The amount of stretching usually expressed 
 in lbs. which a test piece will bear, due to a steady 
 and slowly applied force before it is pulled into 
 parts. 
 
 Ques. Describe the qualities which should be possessed by 
 
 a good boiler-plate ? 
 
 Ans. The plate should not be too large, and 
 should have been satisfactorily tested at the mill 
 by suitable bending tests, and by the testing ma- 
 chine, each sheet being marked with the maker's 
 name, with the figures showing what tensile 
 Strength it had stood in the test. 
 
QUESTIONS AND ANSfVEUS. 23 
 
 Ques. Repeat the answer, using the definitions for boiler 
 materials in their proper places ? 
 
 Ans. The material should be homogeneous^ and of 
 suitable tensile strength and elongation, best suited for 
 the purpose, having an elastic limit that will ensure 
 ihe boilei" being reliable ; it should be tough and 
 ductile ; the material should be inalleable, and in some 
 cases weldable ; that which is of a decidedly cold- 
 short or hot-short nature should be avoided. 
 
 Ques. What is steel ? 
 
 Ans. Steel is iron with a mixture of carbon or 
 an alloy of iron — the alloy being principally carbon 
 steel ; can be melted like cast iron and welded like 
 wrought iron. There are hard and soft steels, 
 according to the process of production and propor- 
 tion of alloy. 
 
 Ques. What is iron ? 
 
 Ans. It is one of the original substances of which 
 the globe is composed. There is very little pure 
 iron, it being nearly always found combined with 
 other things. Wrought iron is iron with the impur- 
 ities worked (or wrought out) and thus rendered 
 soft and malleable, ready to be beaten by the ham- 
 mer into any desired form or rolled into thin plate.* 
 
 Qnes. What is the tensile strength of steel and iron ? 
 
 Ans Of iron according to the table, 50,000 to 
 the square inch average — of steel about 70,000 lbs 
 
 * NoTB. A bar of Iron worth $5.00, It Is stated, is worth $10.50 when inadeln*j0 
 horseshoes, $55.00 in the form of needles, $3,285 in peiiknlle bljules, $i9,480 iD 
 shirt buttons, and $250,000 In balance springs of watches. 
 
26 ENaiNEEBS' EXAMINATIONS. 
 
 Ques. What is the difference between steel and iron ? 
 
 Ans. The steel in ordinary use is an alloy of iron 
 which is cast while in a fluid state into a malleable 
 ingot. To be steel it must be malleable and the 
 product of melting or fusion. This definition 
 excludes pig-iron which is fused or melted, but not 
 malleable; and wrought iron which is malleable but 
 not fused or melted. 
 
 Ques. What is an alloy, define it ? 
 
 Ans. An alloy is a mixture or compound of two 
 or more metals. Ex.: two parts of tin and six parts 
 of lead is " an alloy " suitable for fusible plugs and 
 which melts at 380° fahrenheit. To alloy is usually 
 to reduce the quality of one of the parts, and the 
 least valuable is sometimes called "an alloy." 
 
 Questions and Answers Relating to the Ex- 
 pansion and Contraction of Steam Boilers. 
 
 (^ues. When a boiler is in use what is the effect of heatii."< 
 and cooling it ? 
 
 Ans. The heat expands and enlarges the whole 
 structure, and it should be so constructed and set in 
 the brick work, that this change in form may be as 
 uniform as possible — one part equally with another. 
 
 (Jiies. Does the cold contract the boiler ? 
 
 Ans. Yes, and the process of enlarging and con- 
 tracting is a continual process, as long as the boiler 
 is making steam. 
 
QUESTIONS AND ANSWERS. 27 
 
 Ques. What is the effect of unequal expansion and con- 
 traction ? 
 
 Ans. It is a severe test of the strength of the 
 boiler, the tubes or flues expanding lengthwise with 
 a force sufficient to tear the heads out of the boiler. 
 
 The smaller the proportion of the surface of a 
 boiler that is exposed to the heat, the more active 
 will be the effect of the expanding and contracting 
 forces, and in the case of boilers, set more than 
 half exposed to the influence of the atmosphere, the 
 power exercised by the expansive heat of the fire 
 below and the contraction due to the low tempera- 
 ture above, are almost enough to tear the boiler to 
 pieces. 
 
 Ques. Is any more to be said upon this ? 
 
 Ans. It is the unequal expansion of the shell and 
 tubes that really does more injury to a steam boiler 
 than the expansion and contraction due to changes 
 in the pressure of steam ; the leakage and cases of 
 rupture that so often occur in the lower seams and 
 along the bottom of horizontally fired boilers are 
 unquestionably due to these causes; in very many 
 instances forced firing in getting up steam on first 
 starting the boiler is to blame. 
 
 Ques. Is the force of expansion and contraction known sc 
 that it can be "nearly " calculated ? 
 
 Ans. Yes, iron will exert a strain of 150 pounds 
 per square inch for every degree of temperature. 
 Suppose iron has been heated to 350 degrees and 
 
28 ENGINEERS' EXAMINATIONS. 
 
 cooled down to 60 degrees ; if it is securely riveted 
 or otherwise fastened it will be cooled 350° — 60°= 
 290° X 150 =^44,500=221^ tons, on every square 
 inch of section. 
 
 Ques. Name an instance where this force is likely to be 
 
 langerously exerted ? 
 
 Ans. Where the tubes are placed very near the 
 bottom of a boiler, in which case the pressure is all 
 on the lower side of the heads and the plates that 
 keep them together ; it is not unusual for these 
 plates to be ruptured or the seams sprung under- 
 neath, causing troublesome and often dangerous 
 leaks. 
 
 Ques. How are these difficulties to be avoided ? 
 
 Ans. To avoid the injuries so often caused to 
 boilers in this manner, it is necessary, therefore, to 
 exercise great care in raising steam in new boilers 
 or those that have been blown out and allowed to 
 cool down. The fire should be raised moderately 
 and gradually, and the boiler moderately filled with 
 water, so that the increase in the temperature may 
 be gradual. In cooling off a boiler the same care 
 must be exercised ; nor should the furnace doors be 
 suddenly thrown open or any other proceeding 
 taken that will result in suddenly lowering the boiler 
 temperature, a rapid decrease in the heat being quite 
 as bad for the safety and durability of the boiler as 
 the immoderate and unequal increase above referred 
 to. 
 
ENGINEER'S EXAMINATIONS. 28 
 
 BOILER BRACES AND STAYS. 
 
 Portions of boiler shells which are flat, or which otherwise 
 deviate from the round or egg shape, are necessarily strength 
 ened by means of stays or braces, against the enormous 
 outward pressure caused by the steam. 
 
 The only forms for the shell of boilers which are safe 
 against bursting by internal pressure, without the aid of 
 stays, are the cylinder and the sphere or egg shape. 
 
 The tubes which extend from end to end of the tubular 
 boiler, it has been proved, furnish sufficient holding power to 
 amply stay the jiart of the head to which they are attached 
 and also two inches above the upper row of tubes. 
 
 The flanges of the head being securely united to the shell, 
 and being also curved or dished, it may likewise be safely 
 assumed that no braces need be provided for that part of the 
 head which lies within three (3) inches of the shell. 
 
 The part of a horizontal tubular boiler which needs to be 
 braced therefore consists of a segment of a circle whose 
 circumference lies three inches within the circle of the shell 
 and whose base is two inches above the upper row of tubes. 
 
 Thus in a 6-foot boiler, whose upjier row of tubes is 26 
 belo"w the top of the shell, the part of the head which requires 
 bracing consists in a segment of a circle, the diameter of 
 
30 QUESTIONS AND ANSWERS. 
 
 which is 60 inches and the heighth of which is 21 inches ; 21 
 inches being the measured heighth, 26 inches less the 3 
 inches supported by the flange and the 2 inches supported by 
 the flues. 
 
 Each square inch of this flat surface must be practically 
 supported by the braces, owing to the thinness of the plates, 
 of which the boiler heads are constructed ; and large allow- 
 ance must be made for weakening caused by the age and use 
 of the boiler. 
 
 Questions and Answers Relating to Boiler 
 Braces and Stays. 
 
 Ques. What are some of the names of boiler braces and 
 
 stays ? 
 
 Ans. Crowfoot-brace, jaw-brace, head-to-head- 
 brace or through braces, gusset-stay. 
 
 Ques. What are through braces ? 
 
 Ans. The same as head-to-head braces, /. <?,, they 
 pass from one end of the boiler to another. 
 
 (|ues. What is the crowfoot brace ? 
 
 Ans. This is sometimes called the "solid brace" 
 because it is made of one piece of iron with both 
 ends " flanged out " for the purpose of riveting to 
 both the shell and head. 
 
 Ques. What are radial braces ? 
 
ENOINEEBS' EXAMINATIONS. 
 
 SI 
 
 Ans. These include the crowfoot and braces 
 attached to T iron, and so placed as to run back to 
 the shell in a direct line from the head fastening, at 
 a proper angle. 
 
 Ques. What is the difficult problem in arranging the 
 braces inside a steam boiler ? 
 
 Ans. It is of allowing access to the boiler for 
 examination and still to properly arrange the braces 
 so that each shall bear its due proportion of load. 
 
 (Jues. Of what material should braces be made ? 
 
 Ans. Of the best iron, without weld, and should 
 be, where threaded, upset for six or eight inches 
 from the ends, so that when these ends are threaded 
 the diameter at the bottom of the thread shall 
 slightly exceed the diameter of the brace.* 
 
 * With radial bracing greater strength is obtained by increasing 
 the number of the braces. With through braces, on tlie other hand, 
 increased pressure is provided for by an increase in the size of the 
 braces. This is an iicportant consideration ; for braces that at 100 
 ^)ounds pressure sustain a stress of 7,500 pounds per square inch, would 
 not be proper if the boiler were to carry 125 or 1.50 pounds. The braces 
 should always be proportioned to the surface they have to sustain, 
 and to the pressure of the steam. It may seem needless to refer to so 
 obvious a fact as this, but our experience has shown that too little 
 attention is sometimes paid to it, and hence we feel called upon to 
 urge its importance.— T7i6 Locomotive, Feby., 1S9U. 
 
82 
 
 QUESTIONS AND ANSWERS. 
 
 Ques. What stress is allowed on boiler stays ? 
 
 Ans. The greatest stress to which a boiler sta)^ 
 should be exposed is 6,000 lbs. per square inch of 
 section* at smallest part of stay if made of iron and 
 but little more if made of unwelded steel. 
 
 Qiies. How do you find the absolute stress or strain on the 
 flat surface of a steam boiler, which is carried by the stays 1 
 
 Ans. Choose 
 three stays at three ^ 
 corners of a 
 square — multiply 
 the sides in inches 
 and the result is 
 the number of 
 square inches of 
 surface depend- 
 ing upon one bolt 
 or stay for sup- 
 porting strength. 
 
 Qnes. Give an example. 
 
 Ans. Suppose the stays measure 5 inches from 
 center to center each way with steam at 60 lbs., 
 then : 
 
 5X5 = 25X60= 1,500 lbs. borne by i stay.f 
 
 * This is the U. S. Government rule— iV to A the tensile strength 
 of the iron or steel used for hraces is a safe rule to follow. Many 
 State and City Ordinances allow 7,500 lbs. net stress. 
 
 + The cut exhibits more clearly the process. Measure the distance 
 from A to B in inches and from A to C. Multiply by steam pressure. 
 
ENGINEERS EXAMINATIONS. »3 
 
 Ques. How do you ascertain the number and size of the 
 stay bolts to be used on a flat surface in a boiler ? 
 
 Ans. By finding the total pressure on the unsup- 
 ported portion and dividing it by the lumber of 
 stays, each of which should be strong enough to 
 bear its proportion* 
 
 Ques. In examining the interior of the boiler, which should 
 be done periodically, what are some of the defects for which 
 you would be on the lookout ? 
 
 Ans. For slack braces, for pins missing from the 
 braces, and also to see that none of the^races have 
 more than their due share of strain, and for leaky 
 socket-bolts. 
 
 Qiies. What else would you particularly look for ? 
 
 Ans. For defective riveting, defective heads to 
 the rivets, and for broken and loose stays and braces. 
 
 CJues. When defects are found who is the best party to 
 make the repairs ? 
 
 Ans. An experienced boiler maker. 
 
 (Jues. If no good boUer maker was available what would 
 
 you do then ? 
 
 Ans. I would run no risk but wait until one 
 could be had — unless I myself was capable of mak- 
 ing a temporary repair, and then I would try and 
 prove myself an engineer worthy of my position. 
 
 * The stays should be well fitted and each one carefully tightened 
 and as far as possible each sta y in a group should have the same reg-- 
 nlar strain upon it. 
 
84 ENGINTSERS' EXjLMJN^TIOXS. 
 
 Ques. When a new boiler is put into service and it begins 
 to exhibit signs of distress and leakage after being fired up 
 for ii few days or weeks, what is usually the cause ? 
 
 Ans. It is probably the effect of overstraining, 
 
 Ques. What is the cause of tliis ? 
 
 Ans. Frequently the end plates are too thick or 
 too rigidly stayed, thus preventing the plate from 
 slightly yielding or "breathing" in sympathy with 
 the lengthening and shortening of the flue tubes, 
 constantly taking place with each variation of tem- 
 perature. 
 
 Ques. VTiat remedy is there for this ? 
 
 Ans. That is a boiler-maker's job, and it is some- 
 times done by re-riveting the gussett stays which 
 hold the ends and sides of the boiler together. 
 
 Ques. Name other things causing overstraining ? 
 
 Ans. Overheating the plates, resulting from the 
 use of impure water — this is a very frequent cause 
 of the failure of comparatively new boilers, the 
 deposits cause uneven expansion and contraction. 
 Again, the presence of oils in the boiler, admitted 
 with the feed water when taken from the hot well of 
 a jet condensing engine, or admitted with the steam 
 from the cylinders. This, especially where the water 
 contains carbonate of lime, is responsible for a great 
 deal of the trouble arising from straining. 
 
QUESTIONS AND ANSWERS. 35 
 
 Questions and Answers Relating to Incrusta- 
 tion and Scale. 
 
 When steam is used through the cylinder or heat- 
 ing pipes, all of the impurities, existing in nearly 
 all water, remain to vex the engineer, to impede the 
 action of the generator, and to ultimately even des- 
 troy it. For instance, a 150 h, p. boiler will evapor- 
 ate at least 30,000 lbs. of water in each day of ten 
 hours, and in a month, say, 400 tons. In a compara- 
 tively pure water there would be 100 lbs. of solid 
 matter in that quantity, and in many kinds of spring 
 water as much as 2,000 lbs., and all this remains 
 after the steam is removed. In some " river waters" 
 such has been the condition of the interior of the 
 steamboat boilers that it has resembled " mush " in 
 consistency. 
 
 The impurities are simply foreign bodies, which 
 have no legitimate place in the boiler, and are to 
 be expelled as dangerous foes. 
 
 The sediment remaining after the extraction of 
 the steam forms scale ; and the presence of scale or 
 sediment in a boiler results in loss of fuel, burning 
 and cracking of the boiler, predisposes to explosion, 
 and leads to extensive repairs. It is estimated that 
 the presence of 1-16 inch of scale causes a loss of 13 
 per cent, of fuel, }£ inch 38 per cent., and ^ inch 60 
 per cent. 
 
ENGIXEERS' EXAMINATIONS. 
 
 Ques. what effect does the accumulation of scale on the 
 interior, and of soot on the exterior of a boiler, have upon 
 the economy of the boiler ? 
 
 Ans. The result is to largely increase the amount 
 of fuel consumed, frequently as much as one-fourth 
 in cases of bad scaling. 
 
 The most common defects produced are serious 
 leakage around tube ends, incrustation and scale, 
 deposit of sediment, external corrosion, internal 
 corrosion, and defective pressure gauges. 
 
 (Jues. Is scale all of one kind ? 
 
 Ans. No. The nature and hardness of the scale 
 depend upon the kind of substance held in solution 
 and suspension by the water in the boiler. 
 
 Ques. What general course is the best in dealing with the 
 sediment ? 
 
 Ans. It is more profitable to soften and filter the 
 water than to trust to blowing out or dissolving the 
 sediment and scale after it is there. 
 
 Ques. What is the action of a scum-cock ? 
 
 Ans. Nearly all foreign matter held in solution in 
 water, on becoming separated by boiling, rises to 
 the top in the form commonly called scum, and every 
 boiler should be provided with means for blowing 
 out water from the surface in order to remove the 
 fine particles of foreign matter floating there ; as, if 
 
QUESTIONS AND ANSWERS. 37 
 
 not removed the heavier particles will be attracted 
 to each other until they become sufficiently dense to 
 fall to the bottom, where they will be deposited in 
 the form of scale. 
 
 Ques. Can a mixture be made to use in a great majority 
 of cases of scale. 
 
 Ans. One that has been strongly recommended is 
 made up of 40 lbs. of sal soda, to which is to be 
 added 5 lbs. of catichu and 5 lbs. of salamoniac — 
 one lb. of the mixture to be added to each barrel of 
 water used, until the scale disappears, when the use 
 of sal soda alone is all that is necessary. 
 
 Qiies. Can one preparation be made that will be beneficial 
 in all cases of deposited sediment ? 
 
 Ans. No. This is owing to the variety of chemi- 
 cal matter contained in water, and the varying 
 quantities existing in the steam generators, to say 
 nothing of the different temperatures in which the 
 " compound " may be expected to operate. 
 
 Ques. What is essential in the design of a boiler in ref- 
 erence to the sediment ? 
 
 Ans. It is absolutely essential to the successful 
 use of any boiler, except in pure water, that it be 
 accessible for the removal of scale, for, though a 
 rapid circulation of water will delay the deposit, 
 and certain chemicals introduced into the water may 
 lessen it, yet the only certain cure is periodical in- 
 spection and mechanical cleaning. 
 
38 ENGINEERS' EXAMINATIONS. 
 
 Questions and Answers relating to the Steam 
 Boiler. 
 
 Ques. AVliat are the principal forms of steam generators ? 
 
 Ans. There are three, stationary, locomotive and 
 marine, which terms explain for what uses they are 
 built. 
 
 Ques. Name some of the boilers which come under the 
 
 heading of stationary. 
 
 Ans. The Horizontal Plain Cylinder ; the Two 
 Flue ; the Horizontal Tubular ; the Water-tube ; 
 the Cornish ; the Sectional, etc. 
 
 Ques. Which form is the one most largely in use ? 
 Ans. The Horizontal Tubular. 
 
 Ques. What are its special advantages 1 
 
 Ans. This type is the result of many years of 
 experiments, and aside from a liability to an occa- 
 sional explosion, has proved itself best adapted to 
 
 the wants of steam users. 
 
 Ques. Name some of its special " points " of advantage, 
 
 Ans. It is the cheapest in construction ; it is 
 cylindrical; it encloses the greatest volume of water 
 and steam with the least material ; it is very access- 
 ible for cleaning out and it resists internal and 
 external strains with equal excellence. 
 
QUESTIONS AND ANSWERS. 39 
 
 Ques. What is the pecixliar difference between water tube 
 boilers and others ? 
 
 Ans. The fact of the small tubes being used for 
 holding the water — the distinction is expressed by 
 denominating the older type 'fire tube " boilers. 
 
 (^ues. Name the advantages claimed for water tube boil- 
 ers. 
 
 Ans. The principal claim for superiority is that 
 they are supposed to be safe from disastrous explo- 
 sions. This is owing to the small size or diameter 
 of the tubes of which they are built. 2d. — They are 
 quick "steamers." 3d. — Are accessible for repairs 
 and cleaning and are easily transported — being con- 
 structed in small sections — and easily set up. 
 
 Ques. What are the known disadvantages of the water 
 tube system ? 
 
 Ans. While they make steam quickly, the press- 
 ure as quickly subsides, owing to the small reserve 
 in the water space; the use of cast-iron used in their 
 construction has frequently worked badly in prac- 
 tice and they are said to be more liable to " prime " 
 Ihan other forms. 
 
 Ques. Has any particular form of steam boiler proved 
 
 itself absolutely the best ? 
 
 Ans. No. Tests prove that a square foot of 
 heating surface in both systems, if properly set and 
 with an equally good draft, evaporates nearly the 
 
40 EWGIN'EERS'' EXAMINATIONS. 
 
 same number of pounds of water to a pound of 
 coal. 
 
 Ques. What is the essential peculiarity of the marine 
 boiler ? 
 
 Ans. By U. S. Law all marine boilers must be 
 constructed so that they are fired internally. They 
 are not allowed to be " set " in brick work. 
 
 Qnes. What is Irhe essential peculiarity of the locomotive 
 boiler ? 
 
 Ans. In that it has the steam engine attached to 
 it, thus making it, as it were, a combined engine 
 and boiler, which, with the steam-blast invented by 
 Geo. Stevenson, forms as near a live thing as is 
 known in the world, of man's creation. 
 
 Qiies. About how many pounds of water can be evapora- 
 ted per pound of coal by an ordinary boiler ? 
 
 Ans. From seven to eleven pounds, depending 
 upon the quality of the coal, the draught, and the 
 thickness of incrustation on the interior of the boiler 
 and amount of soot and ashes on the shell and in 
 the tubes. 
 
 Ques. What part of the steam boiler is the strongest '? 
 
 Ans. The strength of a boiler is only that of its 
 weakest part; hence boiler makers are always study- 
 ing methods of perfecting the structure so that every 
 portion has the same resistance. 
 
 (J lies. What is the great cause of steam boiler explosions ; 
 
QVESTTONS AND ANSWERS. 41 
 
 Ans. Weakness in the boiler to withstand the 
 pressure. When a boiler is strong enough to hold 
 the steam it will not explode. 
 
 (^ues. What produces this weakness ? 
 
 Ans. Generally by overheating the plates, caused 
 by shortness of water. When the sheets are heated 
 to a certain point they lose their power of cohesion 
 and become very weak. This causes them to bulge 
 or come down ; and where the pressure is suddenly 
 increased by pumping in water, an explosion takes 
 place. 
 
 (Jues. What other causes can you name which are liable 
 to produce an explosion ? 
 
 Ans. Excessive pressure, beyond the limit for 
 which the boiler was designed ; by bad workman- 
 ship in punching and riveting the sheets ; by bad 
 material used in the construction of the boiler ; by 
 the collection of mud and scale ; and by bad design 
 in which the boiler may not be properly strengthened 
 by stays and braces. 
 
 Qiies. Have you any particular "theory -' as to boiler ex- 
 plosions t* 
 
 *A press despatch from Haverhill, Mass., tells of a hundred horse power 
 boiler which recently sailed into the air like a sky rocket, paused for an 
 instant, then exploded with a deafening report and a concussion which 
 shook the city like an earthquake, and great pieces of iron fleiv in all 
 directions. The cause of this phenomenon is said to have been that the 
 fireman of a hoisting engine boiler fired up at a time when the boiler con- 
 tained an insuflScient amount of water. 
 
42 ENGINEERS' EXAMINATIONS. 
 
 Ans. No. I simply consider an explosion the 
 natural consequence of " letting go " of the forces 
 locked up in the steam and hot water, when sud- 
 denly released from the power of resistance in the 
 generator — being like the "popping" of corn, where 
 the moisture of the kernel is turned into confined 
 steam by heat, until the pressure becomes too great, 
 when an explosion takes place which shatters the 
 grain. 
 
QUESTIONS AND ANSWERS. 43 
 
 Questions and Answers Relating to Firing. 
 
 Ques. How thick should be the body of coal in the fur- 
 nace ? 
 
 Ans. The thickness of fire to be carried depends 
 altogether on the draught. If the draught is strong 
 it should be heavier than when it is weak, and a 
 bituminous (soft) coal fire should be thicker than 
 one of anthracite (hard) coal. For hard coal three 
 to six inches should be the depth, and for soft coal 
 five to eight inches. 
 
 Ques. How should the coal be spread ? 
 
 Ans. It should be kept spread evenly all over the 
 grate, and not allowed to burn in holes, leaving the 
 bars bare, as the cold air will rush in and chill the 
 heating surface. 
 
 Qiies. What is the proper way to clean a fire ? 
 
 Ans. Take a hoe and push the upper part of the 
 fire back, leaving the clinkers, ashes, etc., on the 
 grate ; then pull the ashes, etc., out with the hoe. 
 To clean the back end of the grate, you pull the 
 good fire forward again, and draw the clinkers and 
 ashes of the back end over the fire, and into the ash- 
 pan. Having cleaned it, you must spread the fire 
 evenly all over the grate, and then cover it over with 
 fresh coal, but not too heavily. Care must be taken 
 with anthracite coal, not to let the fire burn too low 
 
44 ENGINEERS' EXAMINATIONS. 
 
 before cleaning it, or else you will not have fire 
 enough left to cover the grate, and it will die out. 
 
 Ques. Can you add anything else about firing ? 
 
 Ans. Whatever is done to a fire should be done 
 quickly, and the furnace door be kept open no longer 
 than necessary. No two fires should be cleaned at 
 the same time. A soft coal fire needs breaking up 
 at short intervals, as it has a tendency to amalga- 
 mate, or crust over on top ; but a hard coal should 
 not be broken up with the bar. All that is necessary 
 to clean it of ashes is to run the slice bar over the 
 grate, and withdraw it without breaking up the fire. 
 
 Qiies. In case of a fire threatening the destruction of the 
 whole establishment, what is the first thing to be done ? 
 
 Ans. The fire under the boilers should be drawn, 
 and the safety valves propped open, so that no explo- 
 sion may take place after the place has been left, this 
 being done for the safety of the engineers, firemen 
 and others. 
 
 Ques. How would you fire a locomotive ? 
 
 Ans. I would distribute the coal — after the fire 
 is well started — evenly in a strip about a foot wide, 
 along the side-sheets and in the corners, being care- 
 ful that there are no holes along the side-sheets and 
 in the corners. This leaves a strip across the fire- 
 box, from the fire-door to the flue-sheet, that J do 
 not put any coal on. 
 
 Ques. How does the coal get into the center ? 
 
QUESTIONS AND ANSWERS. 45 
 
 Ans. I claim that the engine does it. When the 
 coal is put into the fire-box the heat soon drives the 
 gas and other matter out, converting it into coke, 
 and coke being very light the draft will carry it to 
 center of filre-box. The corners and along the sides 
 being a little higher after coal has been put in also 
 aids the draft. The fuel furnished to this strip 
 being coke, it takes very little air to burn it, and the 
 draft drawing the gas from the sides to center of 
 box gives more chance for air and gas to come in 
 contact and burn. 
 
 Ques. Has this method been tried or is it a theory ? 
 
 Ans. It has been tried and it is claimed that a 
 saving of lo per cent, can be made. 
 
 (^iies. Wliat should be the first aim in firing ? 
 
 Ans. To keep an even pressure on the boiler ; 
 to adjust the firing to the work demanded of the 
 engine. 
 
 Ques. What other general rule would you recommend ? 
 
 Ans. To handle the fires, the water supply and 
 the management of the steam without sudden 
 changes — allowing always a sufficient time for the 
 different forces to adjust themselves to their changed 
 conditions. 
 
ENGINEERS' EXAMINATIONS. 
 
 Questions and Answers Relating to the Cir- 
 culation of Water in a Boiler. 
 
 >X-V/ 
 
 Ques. What is circulation of water in a 
 boiler ? 
 
 Ans. When a body of water is 
 heated through the shell of a boiler a 
 movement takes place, and the heated 
 particles rise to the top, and the 
 cooler particles from above take their 
 place. These particles of water do 
 not move the same in all parts of 
 the boiler, in some portions the 
 movement will be upward and in 
 other portions downward, and in this 
 way the circulation in a boiler is pro- 
 duced. 
 
 (^ues. What particular force, or energy, 
 produces this movement ? 
 
 Ans. Heat. The movement of 
 the water is due to the difference in 
 weight of the particles. The water at 
 the bottom becomes heated and 
 expands in consequence, and thus 
 becoming somewhat lighter than the 
 colder particles, is forced upward by 
 the greater density of the cold water 
 above. In this way, too, heat is 
 diffused throughout the whole body 
 of water in the boiler. 
 
 Note.— The cut shows the ebullition as it goes 
 on in a restricted space. 
 
QUESTIONS J-ND ANSWERS. 47 
 
 Qnes. Is there any other force which comes into action 
 to produce tlie circulation ? 
 
 Ans. Yes. The columns of rising steam obtain 
 great physical power, violently and mechanically 
 forcing upwards the water which comes in their 
 
 way. 
 
 (}aes. Is it important to provide for these rising globules 
 or columns of steam ? 
 
 Ans. The flues and water spaces in boilers should 
 be so arranged as to provide a regular and unre- 
 stricted circulation of both the downward and the 
 upward flow of hot water and the upward rush of 
 the steam. 
 
 Qiies. Where does the movement of the particles begin ? 
 Ans. At the bottom. 
 
 (^ues. In what department is the knowledge of the circu- 
 lation of heated water most needed ? 
 
 Ans. In the steam and hot water heating of 
 buildings and work shops, etc. 
 
48 ENGINEERS' EXAMINATIONS. 
 
 Questions and Answers Relating to Combus- 
 tion of Coal. 
 
 Ques. What does the word combustion mean ? 
 Ans. To burn, to kindle, to light. 
 
 (^ues. Before any bm-ning of coal can take place what 
 must occur ? 
 
 Ans. The coal must suffer the preparatory pro- 
 cess of decomposition. It must be dissolved in 
 minute particles of gas or coke. In the combustion 
 of bituminous, or soft coal, there are two distinct 
 operations, viz.: the distilling of the gas and its 
 combustion, and the combustion of the remaining 
 solid carbon or coke. 
 
 Ques. What part is first consumed ': 
 
 Ans. The gas. This unites with the oxygen of 
 the air and burns first. 
 
 Ques. What burns next ? 
 
 Ans. The coke, in the same way as the gas, /. e., 
 the particles of the coke unite with the oxygen of 
 the air and it in turn is consumed. 
 
 (^ues. How is the gas ignited ? 
 
 Ans. The heat under which the gas itself distills 
 will always ignite it if the due admixture of air is 
 immediately obtained. 
 
QUESTIONS AND ANSWERS. 49 
 
 Quos. Is it necessary to have air admitted, and if so, 
 xvbich is the best manner of supplying it to the fuel in order 
 that it may be most effectively consumed ? 
 
 Ans. Air is absolutely essential and is best 
 admitted through the grate-bars to the furnace in 
 innumerable fine jets, since gas and air mix only 
 gradually. Air in bulk mixes only superficially with 
 gas, and, by abstracting heat, cools the furnace. 
 Gases to be thoroughly burned in the furnace must 
 be intercepted at the start, else the combination, 
 which is at best gradual, will not be completed in 
 season. 
 
 (^ues. As to air entering the furnace above the burning 
 fuel, is it desirable ? 
 
 Ans. A proper amount of air (oxygen) entering 
 the furnace above the fuel in small quantities assists 
 somewhat in the combustion of the gases, but a 
 great quantity is detrimental and injurious. 
 
 <{ues. Is there any other theory about this ? 
 
 Ans. Ves. It is claimed that if the fuel is not 
 put on the grate in too thick a layer no necessity for 
 such introduction of air is necessary. 
 
 Ques. In supplying air to the furnace is it an ad .'antage 
 to have it heated ? 
 
 Ans. Probably not. There are certain practical 
 objections to heating the air supply for boiler fur- 
 naces. First, for every 480 degrees Fahr. of added 
 heat its bulk is enlarged by the amount of its 
 
50 
 
 ENOINEEBS' EXAMINATIONS. 
 
 original volume, so that at 3000 degrees, the heat of 
 the interior of the furnace, it has six times its 
 original volume. It is, consequently, more unman- 
 ageable ; and as its contained oxygen retains the 
 same weight, its mixture with the gas becomes moie 
 difficult, while when mixed it can only do the same 
 work as before. It would be much better to con- 
 dense the air than to expand it. Next, if heated by 
 passing through flame or over burning coal, the air 
 will be robbed of a greater or less part of its vital 
 oxygen. This is a positive loss. 
 
 Table of Heat of Combustion. 
 
 Combastible. 
 
 Total units of 
 heat of com- 
 bustion per lb. 
 
 Lbs. of water 
 
 evaporated 
 
 from and at 
 
 212°. 
 
 Hydrogen 
 
 Carbon burned to carbonic 
 
 oxide 
 
 Carbon burned to carbonic 
 
 acid 
 
 Anthracite 
 
 Bituminous coal .... 
 
 Coke 
 
 Cannel coal . 
 
 Petroleum 
 
 Coal gas 
 
 Oak wood (dried) ... 
 
 62,033 
 
 4,400 
 
 14,500 
 14,700 
 14,000 
 13,640 
 14,000 
 20,360 
 20,800 
 7,700 
 
 64-2 
 
 4-55 
 
 15-0 
 15-2 
 14-5 
 141 
 14-5 
 31 
 21-5 
 
QUESTIONS AND ANSWERS. 53 
 
 Ones. What is the combustion chamber ? 
 
 Ans. It is that space under the boiler wnere the 
 burning or combustion of the fuel takes place. 
 
 (Jues. What is the first essential in the construction of the 
 combustion chamber ? 
 
 Ans. It must be large enough, as the fuel before 
 burning must be enormously expanded. It is said 
 that a lump of coal the size of a man's fist or less, 
 must be expanded so that it occupies a cube meas- 
 uring nine feet each way— hence the combustion 
 chamber must be very large indeed compared with 
 the space occupied by the solid fuel as it is placed 
 upon the grate bars. 
 
 Ones. Give the successive processes of combustion as 
 developed in making a coal fire. 
 
 Ans. It is a pi-ogressive process, i, The match, 
 by friction, ignites the phosphorus on its tip, at 150° 
 Fahrenheit ; 2, this sets fire to the sulphur at 500" ; 
 3, this causes the soft wood of the match to burn at 
 800° ; 4, which in turn fires the coal at 1,000°; 
 5, at this point the coal unites with the free oxygen 
 of the air and carries the furnace heat up to 4,000°, 
 more or less, and completes the process. 
 
 Ques. What is a combustible ? 
 
 Ans. Something which burns— coal, oil, wood, 
 are combustibles. 
 
5a ENGINEERS' EXAMINATIONS. 
 
 Questions and Answers Relating to the Cofi 
 struction and Strength of Steam Boilers, 
 
 Ques. Of what material are boilers built ? 
 
 Ans. Of sheet steel, as owing to furnace im 
 provements this superior metal can now be madt 
 cheaper than wrought iron, and, moreover, mild steel 
 has proved to be the best. 
 
 Ques. What is the process of joining the sheets together 
 called ? 
 
 Ans. Riveting, although in certain cases the 
 sheets have been welded, avd in time this may 
 become the general rule. 
 
 Ques. What are the two principal kinds of riveting ? 
 
 Ans. Two — single and double. Single riveting 
 for the girth seams of the boiler and double for the 
 lengthwise seams. In the latter the rivets form a 
 zig-zag line at each joint or seam. 
 
 NOTE.-THE AMERICAN BOILER MAKERS standard of 
 strength, for steel boiler plate is as follows : " Tensile 55,000 to 65,000 
 lbs. per SQuare inch of section ; elongation in 8 inches 20 per cent, for 
 plates % inch thick and under ; 22 per cent, for plates % inch, to ^ 
 inch ; 25 per cent, for plates % inch and under. Specimen piece must 
 bend back on itself (cold) without fracture ; for plates over J4 inch 
 thick specimen must withstand bending 180° (J^ way) round a mandril 
 13^ times the thickness of the plate. Chemical requirements ; phos- 
 phorus not over .04C per cent.; sulpbar ■aot over .030 per cent." 
 
QUESTIONS AND ANSWERS. 
 
 Ques. What size rivets are used in joining the sheets ? 
 
 Ans. They are long enough to bend over and 
 form a head, and of a diameter suited to the different 
 thickness of the plates, ^, ^, ^, according to the 
 specifications for making a boiler when it is first 
 constructed. 
 
 Ques. What is the thinnest sheet which should be used in 
 a boiler ? 
 
 Ans. One-quarter of an inch ; this is the thinnest 
 which can be caulked to advantage. 
 
 Qnes. What is caulking ? 
 
 Ans. This is the closing of the seams after the 
 riveting has been done, and is executed by a blunt 
 chisel ; when the work is done by a round nosed 
 chisel it is called "fullering." 
 
 C^ues. Is a thin plate better than a thick one ? 
 
 Ans. It is said by practical boiler makers that 
 the thinner the sheet — so long as it affords sufficient 
 strength — the longer it will last under the varying 
 strains to which a steam boiler is subjected, and that 
 the caulking will also last longer and better. 
 
 Ques. What are the flanges of a boiler ? 
 
 Ans. They are those parts which are bent over ; 
 this is called flanging ; for example, the heads of the 
 tubular boiler are turned over to be joined to the 
 shell, or body sheets. 
 
54 ENGlNBEttS' EXAMWATIONS. 
 
 Ques. What are the "lugs " of a boiler ? 
 
 Ans. The lugs are the castings riveted on each 
 side of the boiler which support or "lug" it. There 
 are commonly three or four lugs on each side. 
 
 (|ues. Suppose the water should fall below the lowest 
 gauge-cock, what is to be done ? 
 
 Ans. If the fires are light, they should at once be 
 hauled; but should they be heavy, the better plan is 
 to smother the fire with fresh coal, dust, or ashes 
 out of the ash-pans. 
 
 Ques. What are the two principal methods of testing 
 steam boilers ? 
 
 Ans. There are two methods in general use, 
 
 known as the " hydrostatic test " and "hammer test." 
 The former test consists in filling the boiler with 
 water, and then with a hand force-pump raising the 
 pressure up to that which it is supposed the boiler 
 will stand. The "hammer test" is applied in ah 
 accessible parts of the boiler, such as the shell 
 fiues, and braces, by tapping with a light hammer. 
 
 Qiies. What is meant by the pitch line of riveted work ? 
 
 Ans. The distance from center to center of the 
 rivet. 
 
 Ques. How far from the edge of a sheet may a rivet hole 
 be properly made ? 
 
 Ans. A distance equal to the diameter of the 
 rivet hole, /. e., the space between the edge of thf 
 
QUESTIONS AND ANSWERS. 55 
 
 rivet hole and the edge of the sheet must equal the 
 diameter of the rivet. 
 
 (Jues. Does the removal, or punching out, of the metal 
 for the rivet hole weaken the plates and consequently the 
 boiler ? 
 
 Ans. Yes. 
 
 (^ues. What is the rule as to pitch of the rivets in view of 
 this weakening ? 
 
 Ans. There shall be the same strength of iron 
 between the rivets as there is in the rivets themselves. 
 
 (Jiies. What is the most advantageous thickness of boiler 
 plates ? 
 
 Ans. It has been found by experience that a 
 thickness of about ^ of an inch is the most favor- 
 able to sound riveting and caulking of boiler plates; 
 and they are seldom made much thicker or thinner 
 than that thickness; if more strength is needed in a 
 boiler it is better to reduce the diameter of the shell 
 than to increase the thickness of the plates. 
 
 Ques. Is h usual to inake the heads thicker than the shell i 
 
 Ans. Yes. Where the shell is ^ the ends aiv 
 made ^ inch, and in that proportion. 
 
 (Jues. What is the name of the round plate vrhich forms 
 the ends of a tubular boiler ? 
 
 Ans. The tube plate, because in it the ends of 
 the tubes are riveted and bearied. 
 
56 ENGINEERS' EXAMINATIONS. 
 
 (^ues. How many principal kinds of seams are there in 
 boilers ? 
 
 Ans. The " lap " and the " butt " joint, the names 
 of which signify the way in which the sheets are 
 riveted. 
 
 (^ues. How do you ascertain the strength of a riveted 
 seam? 
 
 Ans. It is customary to multiply the tensile 
 strength of the metal by .70 or rs for double 
 riveted longitudinal seams and .56 for single riveted- 
 
 Ques. Give an example. 
 
 Ans. If the steel plates have 60,000 lbs. tensile 
 strength per square inch, then ^ of the square 
 inch would be 22,500 lbs. — multiplying this by. 70 
 gives 15,750 pounds as the strength of the double 
 riveted seam. 
 
 Or multiplying by .56 it gives 12,600 as the 
 strength of the single riveted seam. 
 
 Ques. How does the strength of a seam compare to that 
 of a solid sheet ? 
 
 Ans. The custom is roughly to consider the 
 strength of the single riveted seam to be one-half 
 that of the solid sheet and the double riveted three- 
 fourths. 
 
 ^ues. When inspectors figure the allowable pressure upon 
 a boiler how do they proceed ? 
 
QXmSTlONS jilVD ANSWERS. 0^ 
 
 Ans. They take the strength of the seam and the 
 strength of the weakest plate. They also figure the 
 size and pitch of the rivet. 
 
 Ques. Can jou give a short rule for determining the 
 strength of a boiler — taking the weakest sheet ? 
 
 Ans. Multiply the thickness of the weakest plate 
 in the boiler by its tensile strength per square inch 
 in pounds, and divide the product by one-half of the 
 diameter of the boiler in inches, and multiply the 
 product by .56 for single riveted longitudinal seam^ 
 and by .70 for double riveted longitudinal seams. 
 
 Ques. What will be the strength of a boiler with }^ inch 
 plates of 50,000 lbs. tensile strength, double riveted, and 
 boiler 40 inches in diameter ? 
 
 Ans. One quarter plate gives }( of the strength 
 of the square inch of section = 12,500; divide this 
 by j/2 (of 40 in, diam.) 20 = 625 lbs. This would be 
 for a solid sheet; for double riveted multiply by 
 is = 437tSs lbs. total strength. 
 
 Ques. Would inspectors allow this as the pressure to be 
 carried? 
 
 Ans. No, for they have, by law and custom, " a 
 factor of safety," which only allows one-fourth to 
 one-sixth. 
 
 Ques. With a factor of six, how much willl be allowed m 
 this case? 
 
 Ans. About 75 Jbs 
 
68 t]]S/aiNEt:WS EXAMINATION^. 
 
 Ques. With a factor of five, how much ? 
 
 Ans. About 85 lbs. — the figure being approxi- 
 mated by the inspector — if needed. 
 
 (^ues. "What have you to say as to grate bars ? 
 
 Ans. When the furnace is more than four (4) feel 
 long the bars should be put in in two lengths, but if 
 it is four feet or less in length, one bar will suffice, 
 in which case only two bearing bars will be required. 
 When a center bearing bar is used for two lengths, 
 it should be made like a double grate-bar — that is, 
 with an opening or air-space in the middle. Grate- 
 bars when hot expand considerably, and therefore 
 they should not be put in tight, or too close together, 
 but should have end and side play, otherwise they 
 will bend and twist out of shape and soon be 
 destroyed. 
 
 Ques. Does heating a boiler in the regular "firing" 
 weaken or strengthen it ? 
 
 Ans. It strengthens it, because wrought iron 
 heated to a point less than 600° Fahr. increases in 
 strength, and as at 200 lbs. pressure on the boiler per 
 square inch the temperature is less than 400°, it fol- 
 lows that it grows stronger.* 
 
 *NoTE. — Under a test it has been shown that the strength of irou 
 increases up to 570°, when it begins to decrease with the added heat. 
 At 32° it was 56,000 lbs. per square inch. 
 
 570° " 
 
 " 06,500 " 
 
 r3o° " 
 
 " 55,000 " 
 
 i050° " 
 
 " 33,000 " 
 
 ?.240° " 
 
 " 23,000 " 
 
 1317° " 
 
 " 9.000 " 
 
QUESTIONS JiND ANSWERS. 
 
 Questions and Answers Relating to the 
 Physical Properties of Steam. 
 
 Ques. What is steam ? 
 
 Ans. Steam is an invisible elastic fluid, or water, 
 brought to the state of gas by the application of 
 heat. 
 
 (^ues. What is live steam ? 
 
 Ans. Live steam is steam under pressure and ready 
 to do work through the agency of the steam cylinder 
 or for heating, boiling, etc. 
 
 Ques. What is dead steam ? 
 
 Ans. Dead steam is the opposite of live steam 
 — such as exhaust steam or the vapor which fills the 
 steam generator before there is any pressure. 
 
 Qiies. What is dry steam ? 
 
 Ans. Dry steam is that which holds no water in 
 suspension. High pressure steam has been proved 
 by experiment to be dry like dust. 
 
 i^ues. Wliy is steam invisible except as it is oeing con- 
 densed ? 
 
 Ans. Like many other gases it possesses the 
 quality of invisibility. 
 
 (^iies. What is saturated steam ? 
 
 Ans. This is steam under pressure in contact 
 with water in the boiler; its condensing point agrees 
 with the boilins" point of the water on which it rests 
 
60 ENGINEERS' EXAMINATIONS. 
 
 (^ues. What are the constituents of which steam i» 
 formed ? 
 
 Ans. It contains the same elements as the water* 
 of which it is formed, /. e., two gases, oxygen and 
 hydrogen. 
 
 (^ues. In what proportions do these exist in water and 
 
 steam ? 
 
 Ans. Two volumes of oxygen and one volume 
 of hydrogen, but in weight the hydrogen is the 
 lightest. 
 
 (Jues. Are the oxygen and hydrogen (gases) found in coal 
 the same substances as those described in above answer ? 
 
 Ans. Yes, because these two are simple bodies in 
 themselves, while found in thousands of combina- 
 tions with other original elements. 
 
 Ques. If water is confined in a boiler, and the vessel en- 
 tirely full, and then heated to a high temperature, will there 
 be any steam formed. - 
 
 Ans. No, because steam requires space in which 
 to expand. 
 
 Qnps. How many times is water expanded in being 
 ciiauged into steam at tlie pressure of the atmosphere ? 
 
 Ans. Into sixteen hundred and sixty-nine time,, 
 the volume ; or roughly, 1,700 times. 
 
 Ques. What occurs in the expansion when a pressure is 
 placed upon the boiler ? 
 
QUESTIONS AND ANSWJERS. 61 
 
 Ans, It expands according to the pressure. The 
 greater ihe pressure the less the volume. This is 
 given in tables carefully computed; at a pressure of 
 150 lbs. TO the square-inch the volume is reduced 
 to 284 times, and at 300 lbs. pressure to 96 times. 
 
 (^ues. What is superheated steam ? 
 
 Ans. When steam is separated from the water 
 over which it was formed, and afterwards re-heated 
 to a higher temperature than the water and steam 
 it becomes superheated steam. 
 
 (J lies. Which is the heaviest, a pound of steam or a pound 
 of water ? 
 
 Ans. A pound of steam is the same in weight as a 
 pound of water. It is good form to say that the 
 engine uses " so many pounds of steam " instead of 
 so many pounds of water. 
 
 Qiios. Which is the heavierit at atmospheric pressure, 
 steam or air ? 
 
 Ans. Steam is the lightest, because it always 
 rises. It is about two-thirds the weight of air. In 
 the tables it is put down at .625. 
 
 Qucs. When air is confined with steam inside the boiler, 
 which is then the heaviest ? 
 
 Ans, Both being under more than atmospheric 
 pressure (14 lbs. to the inch), air will be the lightest 
 because its rate or ratio of compression is greater. 
 /. e., steam compresses more readily than air. 
 
63 ENGINEERS' EXAMINATIONS. 
 
 Ques. Is air confined in the boiler with steam considered 
 hurtful or dangerous ? 
 
 Ans. No, as with the immense vohime of steam 
 being formed and used through the engine it soon 
 passes off. Some engines are altogether operated 
 by compressed air. 
 
 Ques. What is wet steam ? 
 
 Ans. Steam full of spray — or with water mechan- 
 ically suspended in the steam. 
 
 Ques. What is the difference l)etween high and low pres- 
 sure steam '? 
 
 Ans. High pressure steam is commonly under- 
 stood to mean steam used in high pressure engines, 
 and low pressure steam is that used at low pressure 
 in condensing engines, heating apparatus, etc., at 15 
 lbs, pressure or under. 
 
 Ques. At what temperature does water evaporate ? 
 Ans. Water evaporates at all temperatures above 
 freezing point, and boils at 212°. 
 
 Qucs. What is absolute pressure of steam ? 
 
 Ans. Absolute pressure is its pressure estimated 
 or reckoned above vacuum ; or the steam pressure 
 shown by the ordinary steam gauge with the pres- 
 sure ot the atmosphere added ? 
 
 Ques . V/hat is initial pressure ? 
 
 Ans. Initial pressure is that in the cylinder of 
 an engine at the beginning of the forward stroke of 
 the piston. 
 
QUESTIONS AND ANSWERS. 63 
 
 Ques. What is terminal pressure ? 
 
 Ans. Terminal pressure is that which would be 
 in the cylinder at the end of the stroke of the piston 
 if the exhaust valve did not open until the stroke 
 was finished ? 
 
 (Jues. What is wire drawing ? 
 
 Ans. Wire drawing is the operation of reducing 
 the pressure of steam between the boiler and 
 the cylinder ? 
 
 Ques. Does the change from water to steam, by the ap- 
 plication of heat, affect the relation of the particles of the 
 different fluids ? 
 
 Ans. As water, the particles are strongly co- 
 hesive, but as steam the particles are repellent. It 
 is this repellant force existing among the infinitely 
 small atoms of steam which appears to give the 
 energy to the mass of steam and renders it service- 
 able. 
 
 Qiies. Does this change mean anything looked at as 
 power ? 
 
 Ans. The fluid, as water, is inexpansive, but the 
 change to steam gives it energy or the ability to do 
 work by the reason of its great expansive or elastic 
 tendency. 
 
 Ques. Has the process we call boiling anything to 
 
 do with steam ? 
 
 Ans. Yes. Boiling is caused by the formation of 
 s^team particles. 
 
64 THE STEAM ENGINE. 
 
 THE STEAM ENGINE. 
 
 While machines may vary greatly in different particulars, 
 the laws of matter are the same, and will remain unchanged 
 for all time ; hence it must be borne in mind that success in 
 the design, care and management of an engine, no matter 
 what may be its size, kind or use, can only be achieved by 
 a close observance of the fundamental laws which govern 
 the formation and use of steam. 
 
 All steam engines may be divided into two great classes, 
 according as they are or are not provided with apparatus for 
 condensing the steam. These classes are: 1, condensing, or 
 low pressure engines; 3, non-condensing, or high pressure 
 engines. 
 
 Engines of the second class are on the whole less econom- 
 ical of fviel than those of the first class, but, having fewer 
 parts and occupying less space, they are much used where 
 simplicity and compactness are considered of more impor- 
 tance than economy of fuel. 
 
 A second mode of classing steam engines is founded on the 
 way in which steam acts on the piston, and is as follows : 
 
 1. Single acting engines, in which the steam performs it& 
 work by its action on one side of the piston only. 
 
THE STEAM ENGINE. 65 
 
 2. Double acting engines, in which the steam exerts 
 energy on eitlier side of the piston alternately. 
 
 3. Rotatory engines, in which the steam drives a revolving 
 piston round. 
 
 A third mode of classification distinguishes engines into — ■ 
 
 1. Non-rotative, in which no continuous rotation is pro- 
 duced, as in single acting pumping engines, steam hainmers, 
 etc. 
 
 2. Rotative engines, in which the motion is finally com-- 
 municated to a continuously rotating shaft. 
 
 Rotative engines are now the most common. Non-rotative 
 engines are exceptional. 
 
 A fourth mode of classing engines is founded on their 
 purposes, as follows : 
 
 1. Stationary engines, such as those used for pumping 
 water, for driving manufactory machinery, etc. 
 
 2. Portable engines, which can be moved from place to 
 place but are stationary when at work. 
 
 3. Marine engines, for propelling vessels. 
 
 4. Locomotive engines, for propelling vehicles on land. 
 
 Stationary engines exist of all the classes belonging to the 
 three previous modes of classification. Portable engines are 
 usually non-condensing, to save space, and to adapt them to 
 situations where injection ^vater cannot be obtained in suffi- 
 cient quantity. Most of them are also double acting and 
 rotative. Marine engines are in general condensing, double 
 acting and rotative. Locomotive engines are aknost all non- 
 condensing, and are all double acting and rotative. 
 
THE STEAM ENGINE. 
 
 In the selection of an engine there are six points to ob- 
 serve relating to it before its purchase : 
 
 L Its simplicity. 
 
 II. Its strength. 
 
 ni. Durability and least wear. 
 
 IV. Economy in the use of steam, 
 V. Regularity of speed. 
 
 VI. Fitness for its work. 
 
 Any intelligent engineer has observed that his engine has 
 an individuality not possessed by any other, and a personal 
 acquaintance with its peculiarity is quite necessary to obtain 
 the best results from it. This remark applies with equal or 
 greater force to the steam boiler and steam pump, and the 
 successful engineer or fireman is the one quickest to under 
 stand "the points " of his machine. 
 
 Great progress has been made in the art of engine building 
 since the introduction of electric hght and power plants and 
 every indication is that still greater perfection will be gained.* 
 
 *NoTE.— In marine engineering the progress in coal economy has 
 been wonderful as may be seen from the following table :— 
 
 Pressure of steam Consumption of 
 
 S'ear, by boiler gauge coal per I. H. P 
 
 persq. In. per hour. 
 
 1330 2 to 3 lbs. 9.0 lbs. 
 
 1840 8 " 5.5 " 
 
 1850 14 " 4.0 ♦* 
 
 I860 80 " 3.0 " 
 
 1870 40 to 40 " 2.6 " 
 
 1880 70 to 80 " 2.2 " 
 
 1886 150 to 160 " 1.5 «* 
 
 1889 175 " 1.4 « 
 
 1890 300 *♦ 1.4 " 
 
QUESTIONS AND ANSWERS. 67 
 
 Questions and Answers Relating to the 
 Steam Engine. 
 
 Ques. Along what lines has the latest development of 
 steam engines been carried? 
 
 Ans. There is a steady progress in the produc- 
 tion of stronger, more rigid engines, using higher 
 steam pressure and to run at higher speeds than 
 now. The automatic cut-off is rapidly displacing 
 the old throttling engine, and much attention is 
 paid to condensers and the compounding of steam. 
 
 Ques. What cause has operated to produce the necessity 
 for stronger and more rigid engines and larger bearing sur- 
 face? 
 
 Ans. The higher speeds — loo revolutions per 
 minute being now not uncommon. A speed of i6o 
 revolutions per minute or 1120 ft. piston speed has 
 been recorded in a 20x42 in. Corliss engine. 
 
 Qnes. Which engine holds first rank as the most econom- 
 ical and generally satisfactory type? 
 
 Ans. The Corliss. 
 
 Ques. In what cases has the compounding in the Corliss 
 engine been found advantageous? 
 
 Ans. Where large power is demanded. In 
 smaller powers the ordinary simple expansion engine 
 has been found sufficiently advantageous. 
 
68 ENGINEERS^ EXAMINATIONS. 
 
 (^ues. What are the two great classes into which engines 
 are divided? 
 
 Ans. Throttling and automatic. 
 
 Ques. Where is the difference? 
 
 Ans. In the principle of regulation in supplying 
 the steam from the boiler to the engine by auto- 
 matic or throttling valves. 
 
 Ques. Which is the oldest system? 
 
 Ans. The throttling principle was almost uni- 
 versal until Corliss introduced his automatic cut-off 
 engine, which he made an immediate success by 
 guaranteeing certain results from the use of a speci- 
 fied amount of fuel. 
 
 Ques. What is the advantage of the automatic cut-oflf as 
 claimed by engine builders? 
 
 Ans. It comes from the fact that most steam en- 
 gines are subjected to variable loads, and quite 
 generally some difference in steam pressure. The 
 economical point of cut-off varies with the load, 
 and the automatic cut-off governor so varies the 
 amount of steam as to secure the best results, pres- 
 sure being constant 
 
 (Jues. In what j)laces are the throttling valve engines 
 without objection ? 
 
 Ans. Where there are but little variations, either 
 in the pressure of steam or in the duty to be per- 
 formed. 
 
QUESTIONS AND ANSWERS. 69 
 
 Ques. What can be said about simplicity in an engine? 
 
 Ans. It is always a point of great importance to 
 build an engine containing the least number of parts 
 and the simplest elements attainable in construction 
 and design, such as the form of frame orbed, piston 
 head, packing rings, cross-head, guides, connecting 
 rod ends, valve gear, valves and regulating appli- 
 ances. 
 
 Ques. What about the strength of an engine? 
 
 Ans. All parts should be so proportioned as to 
 insure the greatest durability and to prevent tremors 
 and strains. 
 
 Ques. What about the point of durability? 
 
 Ans. The least variation in the line of the en- 
 gine, a slight settlement of the foundation, unequal 
 wear of a bearing or failure of oil to flow but for a 
 moment, will cause parts to heat, wear and ulti- 
 mately fracture ; hence the new engine should be 
 speeded only as fast as will enable the mechanism 
 to continue its work with the least wear and stress, 
 thus avoiding the error (now exposed) that the rate 
 of speed of a perfectly constructed engine is unlim- 
 ited. 
 
 Ques. What can you say about economy in the use of 
 steam? 
 
 Ans. This is an element of vital importance and 
 relates to the distribution of the steam in the 
 cylinder. It embraces the least amount of clearance 
 or dead space consistent with the smooth running 
 
70 ENGINEERS' EXA3IINATI0NS. 
 
 of the engine, prevention of the loss of heat from the 
 steam in the cylinder, an initial steam pressure in the 
 cylinder equal to the boiler pressure ; a minimum 
 back pressure ; rapid action of the admitting and 
 cutting off edges of the valve ; a proper amount of 
 cushioning ; and last but not least, a fitness of the 
 engine for its work, in size and the character of the 
 valve gear. 
 
 Ques. Is I'egularity of speed m an engine of importance? 
 
 Ans. One of the most essential features of a 
 good engine is regularity of speed under varying 
 loads. A high attainment in this respect is a vari- 
 ation of only 3 per cent, in two revolutions. 
 
 Ques. What have you to say about the fitness of an en- 
 gine for its proper work ? 
 
 Ans. It is of the utmost importance to choose 
 an engine of the proper size and character to suit the 
 work it is intended for. It is folly to purchase a 
 fixed cut-off engine for greatly varying loads ; it is 
 also poor economy to apply to a small steady load an 
 expensive automatic cut-off engine, or one so large 
 that the ratio of expansion becomes excessive and 
 exceeds the limit of economy. Each steam plant 
 requires its special engine lo be of the proper pro- 
 portion. 
 
 Ques. What is "clearance"? 
 
 Ans. Clearance in a cylinder is the space allowed 
 for the piston to clear the cylinder heads at the end 
 or beginning of a stroke. 
 
QUESTIONS AND ANSWERS. 71 
 
 Clearance is also a term used to include also the 
 volume of the ports. It is evident that this space, 
 as well as the space through which the piston sweeps, 
 has to be filled with steam, 
 
 Ques. What is "lead"? 
 
 Ans. Lead is the amount of the opening of the 
 steam port at the beginning of the stroke of the 
 piston, sometimes called pre-admission. 
 
 (Jnes. How would you give a valve its lead? 
 
 Ans. Place the eccentric sheave ahead of its true 
 position. 
 
 (^ues. To cut the steam off at a given part of tlie stroke 
 liow would ycm alter the valve? 
 
 Ans. By making the width of the face of the 
 valve larger or smaller, as the case demanded, 
 
 (^iies. What would you call this then? 
 Ans. Lap or cover. 
 
 Ques. What is the "lap " of a valve? 
 
 Ans. The "lap " is that part of a valve which is 
 more than necessary to cover the steam ports when 
 the valve is in mid-position. 
 
 Qiies. Is there any lap on the exhaust valve? What is it? 
 
 Ans, Theie is exhaust lap and it is how much 
 the edge of the exhaust valve is over on the cylinder 
 bar beyond the exhaust edge of the port when the 
 valve is in mid-position, 
 
72 ENGINEERS'' EXAMINATIONS. 
 
 i^ues. Why do we have lap on the exhaust edge? 
 
 Ans. To get larger cushion. 
 
 (^ues. What kinds of engines call for this? 
 
 Ans. Those of great size and weight having 
 short and very quick travel. 
 
 Ques. Why is " lap " given a valve at all? 
 
 Ans. To close the port before the piston reaches 
 the end of the stroke, and thus make the steam work 
 bv its expansion. 
 
 Ques. What is the difference betvs^een fixed and movable 
 expansion? 
 
 Ans. The first is expansion by the lap of the 
 valve, and the second is expansion by separate gear- 
 ing or valves. 
 
 i^iics. What other name is given the expansion valve for 
 
 cut-off? ^ 
 
 Ans. The " link." 
 
 (^ues. Does the piston stop at any point of the stroke? 
 
 Ans. Yes ; when passing the centre. 
 
 Ques. What is the operation of the slide valve? 
 
 Ans. To allow the steam to flow alternately first 
 at one end and then to the other of the cylinder and 
 open the opposite port alternately to the exhaust 
 
 (Jues. What is the object of a crank? 
 
 Ans. To convert a straight line motion into a 
 circular one. 
 
QUESTIONS AND ANSWERS. 73 
 
 Qucs. Describe the duties of a slide valve with reference 
 to the positions of the piston? 
 
 Ans, Steam is flowing into the cylinder and 
 pushing the piston, then when the piston has trav- 
 elled one-fourth or one-half or any part of the stroke 
 before determined on, the valve must close the 
 steam port to cause expansion ; it must again open 
 this port to the exhaust just before the piston arrives 
 at the end of the stroke so as to have a vacuum to 
 commence the return stroke with ; it must close the 
 exhaust a little before the piston arrives at the other 
 end to cause cushioning and just before the end of 
 the stroke, it must open this port to steam to com- 
 mence the new stroke. 
 
 Ques. What do we mean by a " vacuum " ? 
 Ans. Any space void of all pressure. 
 
 (^ues. Is an absolute "vacuum " obtainable"? 
 
 Ans. No. 
 
 Ques. Does the condenser have anything near a perfect 
 vacuum? 
 
 Ans. Yes, quite near ; but there is always a 
 small pressure there. 
 
 Ques. To show 11 lbs. what mvist the vacuum gauge read? 
 Ans. 2 2 inches. 
 
 Ques. What does 11 lbs. vacuum mean to a steam en- 
 gineer? 
 
'J'4 ENGINEERS' EXAMINATIONS. 
 
 Ans. It means that he can work his steam down 
 to 4 lbs. before it exhausts, as the condenser has 
 destroyed ii of the i5lbs. atmospheric pressure at 
 which the steam would usually exhaust. 
 
 (^ues. What is implied by the term "back pressure" ? 
 
 Ans. As perfect vacuum is impossible, a certain 
 vapor retards the piston equal to the distance be- 
 tween a perfect vacuum and what the gauge reads. 
 
 Ques. What is the difference between a high and low 
 pressure engine? 
 
 Ans. The first exhausts into the air, having no 
 condenser, while the second exhausts into a con- 
 denser, thus saving the pressure against the atmos- 
 phere. 
 
 (^ues. What is a compound engine? 
 
 Ans. An engine built to get the same expansion 
 not of the steam as does a simple engine, but by 
 means of later cut-off. 
 
 (Jiies. How do they contrive to do this? 
 
 Ans. By using, in addition to the usiial high 
 pressure cylinder, a large second cylinder, where the 
 steam has additional room for expansion before es- 
 caping into the condenser. 
 
 Ques. Does water ever get into the cylinder, and what 
 happens when it does? 
 
 Ans. Sometimes water gets in through priming 
 and is apt to split the piston or blow off the cover of 
 the cylinder. 
 
QUESTIONS AND ANSWERS. 76 
 
 (Jues. Can you get rid of this water? 
 Ans. Yes, by the escape valves. 
 
 (|ues. How can you reverse the motion of a slide valve 
 engine? 
 
 Ans. ist, place the engine on the dead centre, 
 noting the amount of lead on the valve. 2d, slack 
 up the set screw of the eccentric and turn it ahead 
 (same way it has been running) on the shaft until 
 the valve has moved to the extreme of its travel. 3d, 
 move it back until it has the same lead as before, 
 and tighten the set screw. 
 
 Ques. In pvitting in a new shaft, how would you adjust 
 the eccentric ? 
 
 Ans. Put the crank on its top center with the 
 valve at its proper lead at the top. Next fasten the 
 sheave with set bolts to keep the valve lead secure ; 
 when all is connected, then, after a turn of the 
 engine, see if the valve has the proper lead at the 
 bottom when the crank is on the bottom centre. If 
 such is the case, mark the key ways, and key on the 
 sheave. 
 
 Ques. What is the cylinder? 
 
 Ans. The cylinder consists of a cast iron true 
 bored chamber and a steam chest or valve box. 
 
 Ques. What are the openings from the steam cheat to the 
 cylinder called? 
 
 Ans. Steam ports. 
 
•re ENGINEERS' EXAMINATIONS. 
 
 (Jues. Whicli are the exhaust ports? 
 
 Ans. Those which open from the cylinder to the 
 
 air. 
 
 Ques. What is the "stuffing-box " ? 
 
 Ans. The "stuffing box" is that part of the 
 cover through which the piston passes. It is ren- 
 dered steam-tight by a filling or packing of tallowed 
 hemp, etc. 
 
 (Jues. What is the ' ' gland " ? 
 
 Ans. This is the cover which presses down the 
 packing against the rod, and is secured by two 
 screwed bolts. 
 
 Ques. What is cylinder condensation? 
 
 Ans. It is that portion of the steam which con- 
 denses and is deposited on the metallic surface of 
 the cylinder when the cylinder is colder than the 
 steam entering it. 
 
 (^ues. Does this moisture remain in the cylmder? 
 
 Ans. No. It evaporates on the opening of the 
 exhaust, thereby cooling the walls of the cvlinder 
 again. 
 
 (|ues. What is the result of all this? 
 
 Ans. The steam is lost and a back pressure gen- 
 erated thereby. 
 
 (Jues. Is this loss verj^ great? 
 
QUESTIONS AND ANSWERS. 77 
 
 Ans. Yes, sometimes being as much as 50^ of 
 the whole steam consumed. 
 
 Ques. How can this loss be partly remedied? 
 
 Ans. I. By "jacketing " the cylinder with hot 
 steam. 2. By " cushioning " or detaining and com- 
 pressing (thus raising the temperature) a part of 
 the exhaust steam, using the heat thus generated to 
 keep the cylinder hot. 3. Compounding the 
 cylinders. 
 
 Ques. How would you test for a leaky slide valve ? 
 
 Ans. Block the fly-wheel when the slide valve is 
 in the middle of its stroke and open the indicator 
 taps, or the relief cocks, or look at the exhaust pipe. 
 A steady escape of steam indicates a leaky valve, 
 
 Ques. How would you test for a leaky piston ? 
 
 Ans. Block the fly-wheel when the piston is 
 situated at a short distance beyond the beginning 
 of the stroke. Admit steam to the piston and open 
 the indicator tap^ or relief cock, on the exhaust side 
 of the piston. An escape of steam will indicate a 
 leaky piston. The leak may be caused by a leaky 
 slide valve, so this should be tested fii^t. 
 
 Ques. Should engines stand idle for any length of time, 
 what should be done ? 
 
 Ans. They should be turned partly round each 
 day. 
 
78 ENGINEERS' EXAMINATIONS. 
 
 ^ues. What should be done before starting an engme ? 
 
 Ans. The stop valve should be opened a little, 
 before the fire is lighted, so that, while the steam is 
 being generated in the boiler, it may pass through 
 the cylinders and jackets and warm them gradually, 
 the temperature rising as the pressure rises. Mean- 
 while all drain cocks from the slide jackets and 
 cylinders should be opened to allow the steam to 
 flow through, and the condensed steam to pass 
 away. This will prevent the possibility of the 
 cylinder cracking owing to sudden admission of hot 
 steam against the cold metallic walls of the cylinder. 
 This is especially important in cold weather. 
 
 Ques. How would you manage the drain cocks ? 
 
 Ans. The drain cocks should remain open for a 
 few revolutions till all water has been blown out of 
 the cylinder, and then closed. 
 
 (^ues. How about the oil ? 
 
 Ans. I would see that all the lubricators were in 
 pood condition, the holes clear, and the worsteds 
 clean, and that the lubricators were well supplied 
 with oil. 
 
 Ques. If a low pressure or condensing engine, how would 
 y©u proceed ? 
 
 Ans. If a condensing engine, the vacuum gauge 
 should be watched ; and, if the vacuum is not main- 
 tained, the injection, or circulating water, should be 
 
QUESTIONS AND ANSWERS. 79 
 
 regulated. If this does not produce the desired 
 effect, there is probably an air leak through the 
 piston-rod gland, or the air-pump-rod gland, which 
 should be screwed up ; and, if the vacuum is still 
 defective, the cause must be looked for in the foot 
 and head valves or the air-pump bucket valve (if any), 
 or in leaky condenser tubes. 
 
 Ques. How is the horse power of steam engines deter- 
 mined ? 
 
 Ans. By the following rule : Multiply the area 
 of the piston in square inches by the average forct 
 of the steam in pounds and by the velocity of the 
 piston in feet per minute ; divide the product by 
 33,000, and TiT of the quotient equal the effective 
 power. 
 
 Ques. How is the "average force" of the steam in the 
 cylinder, or, as it otherwise is expressed, the "mean effect- 
 ive pressure ", fovmd ? 
 
 Ans. The mean effective pressure can be accu- 
 rately determined only by the aid of an indicator. 
 
 Ques. Without the aid of an indicator how do you pro- 
 ceed 'i 
 
 Ans. When the indicator is not used in the cal- 
 culation the boiler pressure is substituted for the 
 mean effective pressure. Deduct from the result 
 obtained from 40 to 60 per cent, for loss by conden- 
 sation and friction of steam pipes and passages 
 
80 ENGINEERS' EXAMINATIONS. 
 
 decrease of pxessure in cylinder due to expansion, 
 back pressure of exhaust and friction of the working 
 parts.* 
 
 (Jues. How do you proceed with a compound engine ? 
 
 Ans. By the same rule applied to each cylinder — 
 adding the totals together gives the power of the 
 whole. 
 
 Ques. What are compound engines ? 
 
 Ans. Compound engines are those which have 
 two or more cylinders of successively increasing 
 diameters so arranged that the exhaust steam from 
 the first and smallest cylinder is passed forward to 
 Jo work in a second cylinder before escaping to the 
 condenser. 
 
 Ques. What are the particular advantages claimed by 
 compounding ? 
 
 Ans. I, The compound engine enables the full- 
 est advantage to be taken of the expansive power of 
 very high-pressure steam ; 2, The ease with which it 
 may be adapted to work on one or more cranks, 
 thereby reducing the excessive variation of strain 
 which occurs in a single cylindered engine using 
 high pressure steam. 
 
 *NoTE. — The mean pressure in the cylinder when cutting off at 
 
 J4 stroke equals boiler pressure multiplied by .597 
 Jl - - " " " " .670 
 
 .743 
 .847 
 .919 
 .937 
 
QUESTIONS AND ANSWERS. 81 
 
 Ones. How may compoimd engines be classified ? 
 
 Ans. Into those, i, where the piston of each 
 cylinder commences the stroke at the same time ; 2, 
 and those which exhaust from one cylinder before 
 the next cylinder is ready 'to receive it ; in which 
 case the steam is retained, for a portion of the 
 stroke, in a chamber or receiver between the two 
 cylinders. These are termed " receiver " engines. 
 
 Ques. What is to be said about triple and quadruple 
 
 expansion engines ? 
 
 Ans. The principles which govern the construc- 
 tion and management of the compound are the 
 same in the triple and quadruple expansion engines, 
 namely, those in which the steam is expanded in 
 three or four cylinders respectivelv. These are the 
 necessary outcome of increased pressures of steam ; 
 for, since the terminal pressure is about constant, 
 increased pressures involve an increased number oi 
 expansions. And in order to prevent undue range 
 of stress and temperature, three and even four cylin- 
 ders are now employed.* 
 
 * Thus the same reasons which led to the rejection of the single- 
 cylinder engine in favor of the two-cylinder compound, have now led 
 to the rejection of the two-cylinder engine (at least, in marine work), 
 and the adoption of the triple-compound, and in some cases the 
 quadruple compound in its stead. The steamer " Northwest "— 
 Buffalo to Duluth— has engines of the quadruple cylinder type and 
 are worked at 200 lbs. steam pressure, the cylinders being 25", 36", SiM", 
 74" by 43" piston stroke, 120 revolutions, developing with ease 7,000 H. 
 P. The screws (twin) are 13 feet diameter, 18 feet pitch, assuring 
 speed of over 20 miles per hour: 
 
82 ENGINE AND BOILER F1THAQ& 
 
 ENGINE AND BOILER FITTINGS. 
 
 In the efficient operation of a steam plant, next to a well 
 set boiler or boilers with a good draught, there conies an 
 economical, strong and suitably proportioned engine — one or 
 more. 
 
 But, not less an importance and real necessity there must 
 be the connections, fittings and appliances, in the selection of 
 which equal care and good judgment must be brought into 
 play. 
 
 In the choice and arrangement of these fixtures the first 
 thing to be observed is that they shall be of the very best of 
 their kind as far as may be possible. 2d, each appliance 
 should be in fair proportion to the other parts of the plant — 
 neither too large nor too small, and 3d, they should be well 
 and thoroughly ' ' fitted " — the skill of a good engineer Is 
 shown in this as much as in setting a main valve or putting 
 a ■ ' spectacle piece " on a boiler. 4th, every appliance should 
 be kept in the best of working order and in the neatest con- 
 dition with foresight also as to their giving away at an 
 unexpected moment. 
 
 The latter consideration implies the keeping on hand, as 
 far as practical, of duplicates of all fittings and appliances, 
 both in the engine and boiler rooms. Especially is this well 
 where "the plant " is not in the vicinity of shops and supply 
 housea 
 
QUESTIONS AND ANSWERS, 83 
 
 Questions .and Answers relating to Engine 
 and Boiler Fixtures. 
 
 Ones. What are the principal belongings that are usually 
 considered fixtures of a steam boiler ? 
 
 Ans. The safety valve ; globe and check valves ; 
 steam gauge ; the front, containing tube, fire and 
 ash pit doors ; grate bars, with bearing bars ; dead 
 plates ; man and hand hole plates and thimbles ; 
 water gauge cocks and glass gauges ; blow-out 
 apparatus ; fusible plug ; surface blow cocks with 
 scum apparatus ; steam whistle ; and for the brick 
 work, binder bars, anchor bolts, back stays, cleaning 
 out doors, and lugs to support the boiler. 
 
 Ques. What other appliances can you name necessary to 
 complete the operation of a steam boiler ? 
 
 Ans. The pump or injector ; the feed water 
 apparatus with piping of various kinds ; the steam 
 pipe (with globe valve) leading to the engine ; feed 
 water heater; steam-trap; thechimney and damper; 
 the fire-tools, flue brushes and scaling tools, with the 
 hose to wash out the boilers ; water meters ; strain- 
 ers and foot-valves for clearing the water before 
 entering the boiler. 
 
 Ques. What are thimbles in use on boilers ? 
 
 Ans. These are the heavy castings riveted on 
 the upper shell of the boiler with flanges planed to 
 which to bolt the safety valves or pipe connections 
 —a thimble in gas pipe definitions is " a connection." 
 
!1 ENGINEERS' Eli. AMI NATIONS, 
 
 <^ueSo What is a globe valve ? 
 
 Ans. A globe valve takes its name from its shape. 
 It is a valve in a round chamber. 
 
 (^ues. How should globe valves be attached ? 
 
 Ans. So that the pressure comes under the valve, 
 or at the side, for if the valve should become loose 
 from the steam (which they often do) if the pressure 
 is on top, there would be a total stoppage of the 
 steam. 
 
 Ques. What is a valve ? 
 
 Ans. A valve has a seat and is generally turned 
 by a circular handle fitted to the spindle — the best 
 example of a valve is that of an ordinary house 
 pump, where the valve opens upward to admit the 
 water and closes downward to prevent its return. 
 
 (^ues. What is a cock ? 
 
 Ans. A cock is a valve but a valve is not a cock 
 — the cock is a cone-shaped valve slotted and fitted 
 with a handle — example : the try-cocks of a boiler 
 are cocks with their openings in line with the blow- 
 off pipes. 
 
 (Jues. What is a relief valve ? 
 
 Ans. It is a valve so arranged that it opens out- 
 ward when a dangerous pressure or shock occurs. 
 
 QueSo What is a back pressure valve ? 
 
 I 
 
 J 
 
QUESTIONS AND ANSWERS. 85 
 
 Ans. These are ball (or clack) valves in a pipe 
 which instantly assume the seat when a back press- 
 ure occurs. Their name signifies their use — to 
 maintain a constant back pressure in heating 
 systems. 
 
 (|ues. What is a three-way cock ? 
 
 Ans. It is one having three positions in which to 
 direct the fluid in three ways. There is also a three- 
 way valve. ^ 
 
 Ques. What is a check valve ? 
 
 Ans. A valve placed between the feed pipe and 
 the boiler to prevent the return of the water, and 
 similar uses. 
 
 Ques. What is a ball valve ? 
 
 Ans. It is a valve occupying a hollow seat. 
 These valves are raised by the passage of a fluid and 
 closed by their own weight. 
 
 (^ues. What is the throttle valve ? 
 
 Ans. This is the valve used to admit steam to 
 the engine and so used (in stationary service) to 
 distinguish it from the main stop, valve located near 
 the boiler — to throttle means to choke — hence the 
 throttling of the steam. 
 
 Ques. What is a reducing valve ? 
 
 Ans. This is a pressure-regulating valve and 
 designed to reduce the pressure from a high point 
 
ENGINEERS' EXAMINATIONS. 
 
 in the boiler to a low one in a system of steam heat- 
 ing. 
 
 (Jues. How should steam valves be connected ? 
 
 Ans. So that the valve closes, against the con- 
 stant steam pressure. 
 
 Ques. What will prevent cracking and pounding noises in 
 
 steam pipes in steam heating '? 
 
 Ans. A thorough drainage of the pipes. 
 
 (Jues. In steam and cast iron pipe how is the diameter 
 given in the tables ? 
 
 Ans. By the internal diameter. 
 
 Ques. And the diameter of boiler tubes ? 
 Ans. By the external diameter 
 
 Ques. How is the strength of steam pipes, elbows, tees, 
 threads, etc. , calculated for the safe working pressure ? 
 
 Ans. By the same rules that are used in figuring 
 the strength, strains, etc., of the steam boiler. 
 
 Ques. What factor of safety would be best in view of the 
 small diameter of the pipes ? 
 
 Ans. A tensile strength of 50,000 lbs. to the 
 square inch may be assumed with safety with a 
 factor of 4. 
 
 (Jues, What would you do with rusted spots ? 
 
 Ans. Regarding rusted spots or places where 
 corrosion has taken place, the thickness of good 
 
QUESTIONS AND ANSWERS. 87 
 
 iron remaining should be taken as the thickness of 
 the pipe or fitting, although small places having an 
 area of i square inch or less may be ignored so long 
 as the original thickness of the material remains ; 
 but where the corroded area exceeds this, full allow- 
 ancs must be made, A number of small places 
 corroded, pitted or grooved and closely connected, 
 require that only the thickness of good iron remain- 
 ing shall be considered as the thickness of the 
 material. 
 
 v^ues. What is the tensile strength of cast and malleable 
 iron — of which connections are mostly made ? 
 
 Ans. The mean tensile strength of cast iron is 
 from 16,000 to 20,000 lbs. and a factor of safety of 4 
 should be employed. The mean tensile strength of 
 malleable iron ranges from 30,000 to 40,000 lbs., and 
 unless tests are made to determine the strength it is 
 better to assume the smaller number, allowing as 
 before a factor of safety of 4. 
 
 Ques. What is to be stated about the pipe threads ? 
 
 Ans. The threaded portions of pipes and fittings, 
 when the greater portion of the thread is entered 
 and the joint made in a workman like manner, will 
 have sufficient strength to withstand the strain on 
 the same principle that the single riveted girth 
 seams have sufficient strength to withstand the 
 strain, even though the longitudinal seams of the 
 boiler be double riveted. 
 
ENQlNEt^BS' EXAMWATtONS. 
 
 Ques* In taking charge of a new steam plant what is the 
 first thing an engineer should do ? 
 
 Ans. Make himself familiar with tne water and 
 steam pipes and office of the valves connected with 
 such pipes. 
 
 Ques. "What are the dead centres or dead points of an 
 engine ? 
 
 Ans. At two instants in each revolution, the 
 direction of the crank coincides with the line of 
 connection (or straight line joining the centre of the 
 joints of the connecting rods.) The positions of the 
 crank pins at those instants are called dead points, 
 and they correspond to the ends of the stroke of the 
 pistons when its velocity vanishes. 
 
 (^iies. What means are provided to overcome the effects of 
 these dead jjoints without jar or irregularity ? 
 
 Ans. It is to diminish the irregular action caused 
 by the existence of these dead points and also to 
 facilitate the starting of engines when the crank 
 happens to rest upon one of them that engines are 
 combined by pairs or threes. 
 
 Ques. V/hat other device is used to prevent in stationary 
 engmes the fluctuations in speed caused by the dead centres 1 
 
 Ans. The fly wheel. 
 
 Ques. Why are they not used in marine and locomotive 
 engines ? 
 
 Ans. In marine service the propeller, whether 
 paddle or screw, answers the purpose of a fly wheel; 
 in locomotives the entire engine suffices to prevent 
 excessive fluctuations. 
 
nrmsTioNs AND Asswmts. 89 
 
 C|uestiojis and Answers Relating to the 
 Safety Talve. 
 
 Oues. What is a safety valve ? 
 
 Ans. it is a bonnet or conical valve loaded with 
 a weight equal to the greatest extra pressure likely 
 to be exerted by the steam on the boiler. 
 
 Ques. What is the particular office of the safety valve ? 
 
 Ans. To relieve the boiler from a pressure which 
 may become dangerous and cause an explosion. 
 
 Ques. Is the sound of steam from a safety valve a sign of 
 danger ? 
 
 Ans. No, it is a token of safety ; it shows the 
 valve to be in operation, and if properly set, a sure 
 protection. 
 
 Ques. What danger exists when a safety valve " sticks " 1 
 
 Ans. The valve holds the pressure until it gets 
 higher and higher, until so very high that the safety 
 valve finally gives way and allows so much steam to 
 escape at once that it changes the condition or 
 balance of the steam and water inside the boiler, 
 causing danger of an explosion. 
 
 Ques. How should this be guarded against ? 
 
 Ans. By raising the valve, when under pressure, 
 once or twice a day — doing so very gently and 
 gradually — to make sure that it is in working order. 
 
90 EHrOINEEES' EXAMINATIONS. 
 
 Ques. When a safety valve is described as a 2 inch val\«e 
 or a 23^ inch valve, what is indicated by the aescription i 
 
 Ans. It means that 2 inches, or 2).^' inches is the 
 diameter of the pipe. 
 
 (^ues. What part of the boiler is preferable for the position 
 of the safety valve ? 
 
 Ans. It is best placed upon the boiler at the 
 part furthest away from the water line, so as to be 
 unaffected by the k aming of the water — if any exists. 
 
 (jues. Is there more than one variety of the safety Valve? 
 
 Ans. Yes. The Lever, or the common form, and 
 the Spring loaded safety valve ; also the dead-weight 
 safety valve. 
 
 Ques. What is the "pop " safety valve ? 
 
 Ans. It is a well-known form of spring valve 
 and takes its name from the fact that it takes a little 
 more pressure to raise it off its seat than what it is 
 set at, consequently it releases itself with a "pop *' 
 
 (^ues. What are the points of contact of a valve called ? 
 
 Ans. The fixed part is called the seat of the 
 valve and the part resting upon it is called the face 
 of the valve. The seat is preferably adjusted at an 
 angle of 45 degrees and the face made to fit. 
 
 (^ues. What is the val ve spindle ? 
 
 Ans. It is the small guiding rod which moves 
 upwards and downwards with the face of the valve. 
 Its office is to keep the two faces opposite and cause 
 the rise and fall to be perfectly even and true. 
 
QUESTIONS AND ANSWERS. 91 
 
 Ques. What are the most essential ]iroblems to be per- 
 formed in reference to the steam plant, and why V 
 
 Ans. Those relating to the safety valve ; because 
 the safety valve is the most important fixture 
 belonging to the steam boiler. 
 
 Qiies. Why should the size of the safety valve bear a cer- 
 tain proportion to the size of the boiler '? 
 
 Ans. Because if the valve is too large it is liable 
 to be blown off when raised by excessive pressure, 
 and if too small then it will not relieve the boiler in 
 time to prevent an explosion 
 
 Ques. Can you give the rules for size best proportioned ? 
 
 Ans. Rankine's rule for the dimensions of safety 
 valves is : Multiply the number of pounds evaporated 
 per hour by .006 and the product will be the area in 
 square inches of the valve. The United States 
 steamboat inspection law requires for the common 
 lever valve one square inch of area of valve for every 
 two square feet of area of grate surface. A rule 
 adopted by the Philadelphia Department of Steam 
 Engine and Boiler Inspection is : i. Multiply the 
 area of grate in square feet by the number 22.5, 
 2. Add the number 8.62 to the pressure allowed per 
 square inch. Divide (1) by (2) and the quotient 
 will be the area of the valve in square inches. 
 
 Qnes. How would you figure for 36 feet of grate surface 
 with 80 lbs. pressure ? 
 
 Ans. 36 sq. feet of grate X 22.5 — 810.0, Press- 
 ure allowed 80 lbs. + 8.62 = 8S.62; 810 -r- 88.62 = 
 9.14 or a valve having a diameter of 3.4". 
 
92 ENQINEERS' EXAMINATIONS. 
 
 I 
 
 (Jnes. What three elements enter into each calculation 
 relating to the safety valve ? 
 
 Ans. I, The number of square inches on the face 
 of the valve and the pressure of the steam ; 2, the J 
 weight of the lever and valve in lbs ; 3, the amount ^ 
 of the weight and its position on the arm of the 
 lever.* 
 
 Ques. How do you find the square inches of a valve, the |l 
 diameter being known ? ^ 
 
 Ans. By multiplying the square of the diameter 
 of the circle by the decimal .7854. 
 
 Ques. How would you figure the pressure on a 3 inch 
 valve with 100 lbs. boiler pressure ? 
 
 Ans. Thus — 3 X 3 = 9 in. 
 
 9 X .7854 = 7.068 area, 
 7.068 X 100 = 706.8 lbs. 
 
 (Jues. What is the Lever and what are its essential points? 
 
 Ans. Of the six mechanical powers (pully, v/heel, 
 screw, etc.) the lever is the first in the list. 
 
 There are three essentials in the lever — i, the 
 fulcrum, or prop ; 2, the power; and 3, the weight; 
 or, differently stated, i, the point on which the bar, 
 or lever, turns (the prop, or fulcrum); 2, the place 
 
 4 
 
 * The weiglit of the lever and valve is of so little importance in the 
 matter of pressure that examining engineers usually omit it from their 
 questions. 
 
QUESTIONS AND ANSWERS. 93 
 
 where the power is applied ; and 3, the point where 
 the weight is applied.* 
 
 Ques. How many classes or kinds of levers are there ? 
 
 Ans. There are three classes of the lever, num- 
 bered according to the relative position ot the 
 fulcrum ; the safety valve lever is a lever of the third 
 kind. 
 
 Ques. What is the method of calculating the power of the 
 lever ? 
 
 Ans. The same calculation applies to each of 
 the three classes of levers. 
 
 w , '- 
 
 -t 
 
 ^w' 
 
 \ 
 
 ^ 
 
 Rule for Calculating L^evers. 
 
 The force (P) multiplied by its distance from the 
 fulcrum (F) is equal to the weight (W) multiplied 
 by its distance from the fulcrum. 
 
 Note.— When two forces act upon each other hy means of any 
 machine, that which gives it motion is called THE POWER, and that 
 which receives, the weight (WEIGHT). See illustration. 
 
 The calculations are to be made in inches for distances and in 
 pounds for the forces and weights, and the calculations are made for 
 the action of mechanical powers upon the supposition that their action 
 is not affected by their own weight, or by friction and resistance. 
 
 * In the safety valve lever the prop or fulcrum is the hinge-joint 
 upon which the arm moves, the point where the power is applied is the 
 conical valve being pressed upward by the steam, and the point where 
 the weight is applied is oa the arm of the l^iver. 
 
94 
 
 ENGINEERS' EXAMINATIONS. 
 
 Ques. What rule of arithmetic can be used to advantage 
 in working safety valve problems ? 
 
 Ans. The rule of three or rule of proportion." 
 
 \{ a J- ^t li^ 
 
 Note.— In the illustration F is the fulcrum ; "V is the point where 
 the pressure is exerted ; W is the weight ; FV is 6 inches ; and VW is 
 10 inches ; therefore FW is 16 inches. 
 
 Ques. When the length of the lever, the weight and 
 length of the short arm are known, give the rule for finding 
 the steam pressure the weight will hold, give both rule and 
 example. 
 
 Ans. Rule (One). 
 
 Multiply the length of the lever by the weight and 
 divide the product by the length of the short arm. 
 
 * This " rule of three " is one of the most useful in the whole range 
 of mathematics ; a rule by which, when three numbers are given, a 
 fourth number is found. 
 
QUESTIONS AND ANSWERS. 95 
 
 Example. 
 The length of lever being 20 inches, the weight 20 
 lbs. on the end of it, and the short arm being 4 
 inches, then 
 
 The length of the lever, 20 
 
 Multiplied by the weight, 20 
 
 Divided by the short arm, 4)400 
 
 Answer, 100 lbs. resistance.* 
 
 Ones. When tlie diameter of the valve, the steam press- 
 ure, the length of the short arm and the weight are known, 
 what is the rule to find the place to hang the weight '? Give 
 rule and example. 
 
 Ans. Rule (Two). 
 
 Multiply the steam pressure in lbs. by the length 
 of the short arm of the lever in inches, and divide 
 the product by the weight of the ball. 
 
 Example. 
 The diameter of the valve being 2j4 with steam 
 at 60 lbs. gives the resistance to be overcome (i. e., 
 2.5 X 2.5 X. 7854 = 4/Tr area of valve multiplied by 60 
 ibs ) 294 lbs.; the short arm of the lever, 3 inches; 
 '.veight of ball, 40 lbs. Now then : 
 The resistance (steam pressure) = 294 
 The short arm, 3 
 
 Divide by weight, 40)882 
 
 22 05 inches of lever. 
 
 ■^ This 100 wonld represent a valve area of SJ.^ sq. in. at 40 lbs. press- 
 are, etc. 
 
m ENGINEERS' EXAMINATIONS. 
 
 Ques. When the steam pressure, the short arm, and the 
 length of the lever are known, to lind weight of ball needed. 
 Give rule and example. 
 
 Ans. Rule (Three). 
 
 Multiply the steam pressure by the short arm, and 
 divide the product by the length of the lever, the 
 answer is the weight of the ball. 
 
 Example. 
 The steam pressure (as in the last example) being 
 294, the short arm 2 inches, and the length of the 
 lever 30 inches. Now then : 
 
 The steam pressure, 294 
 
 Multiplied by the short arm, 2 
 
 Divided by the lever, 30)588 
 
 Weight of ball needed, 19.O lbs. 
 
 Ques. When the weight, length of lever and the steam 
 pressure (resistance) are knoM-n, to find the length of the 
 short arm. Give rule and example. 
 
 Ans. Rule (Four). 
 
 Multiply the length of the lever by the weight and 
 divide the product by the steam pressure. 
 
 Example. 
 The lever being 20 in., weight 20 lbs., steam pres*;- 
 ure 100 lbs. Now then : 
 
 Length of lever, 20 
 
 Weight, 20 
 
 Divide by steam pressure, 100)400 
 
 Length of short arm, 4 inches * 
 
 * This 100 represents the total steam pressure on the valve— tlie 
 s'yaraple given being the reverse of the one for rule one. 
 
QUESTIONS AND ANSWERS. 97 
 
 Ques. If the ball is removed from the lever can there Iw 
 any steam pressure on the boiler ? 
 
 Ans. Yes ; that due to the weight of the valve 
 and stem. If they weigh, say 2 lbs., and the area of 
 the valve is 7 sq. inches, then that would cause a 
 pressure of f of one lb. before the steam blows off. 
 
 Ques. What about the lever itseK ? 
 
 Ans, The weight of the lever also operates the 
 same way, except it is not a dead weight. 
 
 Ques. Explain why it is not a dead weight. 
 
 Ans. If you have a lever 30 inches long and it 
 has the same size from end to end, its balancing 
 center will be in the middle, or 15 inches. If the 
 lever (bar) weighs 8 lbs. it will have the effect of 
 hanging a ball of 8 lbs., 15 inches from the fulcrum. 
 
 Ques, Is there anything else which should be thought of 
 in figuring the safety valve problems ? 
 
 Ans. Yes, a possible difference in the true 
 diameter of the valve or connection pipes — the 
 opening of the valve may be 2 inches diameter, but 
 the circle of contact of face and seat may be 2)4 — ■ 
 this would make a difference of nearly j4 sq inch of 
 
 area. 
 
 * This diflEerenoe need not be considered important in view of tho 
 factor of safety (6) usually allowed, i. c, the boiler is made to with- 
 stand six times the ordinary pressure : But, it bears upon the questio'a 
 of omitting the weight of valve spindle and lever from comirtoa calcu- 
 lations. 
 
98 
 
 ENGINEERS' EXAMINATIONS. 
 
 Table of Properties of Saturated Steam. 
 
 Absolute 
 
 pressure 
 
 in lbs. per 
 
 sq. in. 
 
 Tempera- 
 ture Fah. 
 
 Total beat of 
 
 evaporation 
 
 from water at 
 
 33° F. 
 
 Volume 
 per lb. in 
 cubic feet. 
 
 1 
 
 103.0 
 
 1113.0 
 
 330.36 
 
 2 
 
 136.4 
 
 1130.5 
 
 173.08 
 
 3 
 
 141.6 
 
 1135.1 
 
 117.52 
 
 4 
 
 153.1 
 
 1128.6 
 
 89.62 
 
 5 
 
 163.3 
 
 1131.4 
 
 72.66 
 
 6 
 
 170.1 
 
 1133.8 
 
 61 21 
 
 •? 
 
 176.9 
 
 1135.9 
 
 52 94 
 
 8 
 
 183.0 
 
 1137.7 
 
 46.70 
 
 9 
 
 188.4 
 
 1139.4 
 
 41.80 
 
 10 
 
 193.3 
 
 1140.9 
 
 37.84 
 
 11 
 
 197.8 
 
 1143.3 
 
 34.63 
 
 12 
 
 203.0 
 
 1143.5 
 
 31.90 
 
 13 
 
 305.9 
 
 1144.7 
 
 29.57 
 
 14.7 
 
 312.0 
 
 1146.6 
 
 26.36 
 
 15 
 
 213.1 
 
 1146.9 
 
 35.85 
 
 16 
 
 216 3 
 
 1147.9 
 
 34.32 
 
 17 
 
 219.5 
 
 1148.9 
 
 22.96 
 
 18 
 
 333.5 
 
 1149.8 
 
 21.78 
 
 19 
 
 235.3 
 
 1150.6 
 
 20.70 
 
 30 
 
 238.0 
 
 1151.5 
 
 19.72 
 
 31 
 
 230.7 
 
 1152.3 
 
 18.84 
 
 22 
 
 233.3 
 
 1153.1 
 
 18.03 
 
 23 
 
 235.8 
 
 1153.9 
 
 17.26 
 
 24 
 
 238.2 
 
 1154.6 
 
 16.64 
 
 25 
 
 240.5 
 
 1155.3 
 
 16.00 
 
 36 
 
 242.7 
 
 1156.0 
 
 15.38 
 
 27 
 
 244 8 
 
 1156.6 
 
 14.86 
 
 38 
 
 246.8 
 
 1157.2 
 
 14.37 
 
 29 
 
 248.7 
 
 1157.8 
 
 13.90 
 
 80 
 
 250.5 
 
 1158.3 
 
 13.46 
 
QVESTIONS AND ANSWERS, 
 
 99 
 
 Table of Properties of Saturated Steam. — Continued."^ 
 
 Absolute 
 
 pressure 
 
 in lbs. per 
 
 sq.. in. 
 
 Tempera- 
 ture Fah. 
 
 Total heat of 
 
 evaporation 
 
 from water at 
 
 32° F. 
 
 Volume 
 per lb. in 
 cubic feet. 
 
 35 
 
 259.3 
 
 1161.0 
 
 11.65 
 
 40 
 
 267.0 
 
 1163.4 
 
 10.28 
 
 45 
 
 274.4 
 
 1165.6 
 
 9,18 
 
 50 
 
 281.0 
 
 1167.6 
 
 8 81 
 
 55 
 
 287.1 
 
 1170.0 
 
 7.61 
 
 60 
 
 292.6 
 
 1171.2 
 
 7.01 
 
 65 
 
 298.0 
 
 1172.7 
 
 6.49 
 
 70 
 
 302.8 
 
 1174.3 
 
 6.07 
 
 75 
 
 307.5 
 
 1175.7 
 
 5.68 
 
 80 
 
 312.1 
 
 1177.1 
 
 5.35 
 
 85 
 
 316.1 
 
 1178.4 
 
 5.05 
 
 90 
 
 320 3 
 
 1179.6 
 
 4.79 
 
 95 
 
 324.1 
 
 1180.8 
 
 4.55 
 
 100 
 
 827.7 
 
 1181.9 
 
 4.33 
 
 105 
 
 331.3 
 
 1182.4 
 
 4.14 
 
 110 
 
 334.6 
 
 1184.0 
 
 3.97 
 
 115 
 
 338.0 
 
 1184.5 
 
 3.80 
 
 120 
 
 341.1 
 
 1186.9 
 
 3.65 
 
 130 
 
 347.2 
 
 1187.9 
 
 3.38 
 
 140 
 
 352.9 
 
 1189.6 
 
 3.16 
 
 150 
 
 358.3 
 
 1191.2 
 
 2.96 
 
 160 
 
 363.4 
 
 1192.8 
 
 2.79 
 
 170 
 
 368.3 
 
 1194.3 
 
 2,63 
 
 180 
 
 383.0 
 
 1195.7 
 
 2.49 
 
 190 
 
 377.5 
 
 1197.1 
 
 2.37 
 
 200 
 
 381.8 
 
 1198.4 
 
 2.26 
 
 250 
 
 400.8 
 
 1204.2 
 
 1.83 
 
 300 
 
 417.1 
 
 1209.2 
 
 1.54 
 
 350 
 
 430.1 
 
 1212.2 
 
 1.33 
 
 400 
 
 445.0 
 
 1217.7 
 
 1.18 
 
 Lcf 
 
 ♦ Regnault. 
 
iOO SATURATED STEAM. 
 
 SATURATED STEAM. 
 
 This has been defined on page 59 as tlie steam wliicli rests 
 upon the water witliin a boiler under pressure. Attention is 
 no'w invited to tlae Tables (Regnault's) on the two preceding 
 Images. 
 
 Let water at 32° be heated in a closed vessel, such as an 
 ordinary steam boiler, containing space for the accumulation 
 of steam, and let heat be gradually applied. Then the tem- 
 perature of the Avater will gradually rise, and steam will be 
 formed. 
 
 As the heat is increased, the temperature, pressure, and 
 density, or weight per cubic foot, of the steam increase 
 indefinitely, so long as the strength of the boiler is not 
 exceeded ; and the relation bet^veen the tempei'ature, press- 
 ure, and density always bears a certain fixed relation. 
 
 If heat is applied so as to maintain the temperature con- 
 stant, the pressure and density remain constant also, and 
 evaporation ceases. If a communication be opened between 
 the boiler and engine, on escape of steam from the boiler the 
 pressure is momentarily reduced and re evaporation com- 
 mences rapidly. So long as the temperature is maintained, 
 no sensible variation of pressure is noticeable in a boiler sup- 
 plying steam to an engine. 
 
SATURATED STEAM. ]01 
 
 It will be observed from the tables that saturated steam 
 under a given pressure has a fixed temperature, also that the 
 temperature and density increase with the pressure. 
 
 But it will be further noticed that the total heat increases 
 in a very £.low ratio compared with the pressure and temper- 
 ature, there being only a very small increase of total heat 
 per lb. of steam as the pressure increases. This is an 
 important point in practice when considered in reference to 
 coal consumption, for it shows that it is not much more 
 costly in fuel to generate high-pressure steam than low- 
 pressure steam, weight for weight ; and that far more work 
 can be obtained from it when used expansively than from 
 the same weight of low-pressure steam — hence the economy 
 of high-pressure steam. 
 
 In this connection it is interesting and important to com- 
 pare the difference in the weight of water requu-ed to cool a 
 given weight of water, with that required to cool the same 
 weight of steam at the same temperature. 
 
 This is owing to the mysterious element which exists in 
 steam under pressure — very like the unknow-n essential prop- 
 erty of electricity — called latent heat. In generating water 
 into steam there is absorbed about five and one-half times as 
 much heat as is required under atmospheric pressure, to 
 raise the temperature of the water from freezing point, 32° 
 F., to boiling point, 212° F., an amount of heat which 
 if the v^ater were a fixed solid %vould, it is said, render it red 
 hot by daylight. Tested by a thermometer the steam will 
 show only 212°, but by experiment 1000°, nearly, have been 
 
102 
 
 SATURATED STEAM. 
 
 added, which is stored up in some hidden unaccountable 
 way ; this is called the latent heat of steam. 
 
 There are two sorts or conditions of heat in the process of 
 steam production operating upon "water : 1, Sensible heat; 2, 
 Latent or insensible heat ; hence the constituent or total 
 heat of steam consists of its latent heat in addition to its 
 sensible heat. 
 
 The appropriation of the heat expended in the generation 
 of one pound of saturated steam at 212° F. , from water sup- 
 plied at 32° F., may be exhibited thus : — 
 
 To Generate one Pound of Steam at 212° F. 
 
 
 Units of heat. 
 
 Mechanical equiva- 
 lent in foot-pounds. 
 
 The sensible heat : — 
 
 
 
 1. To raise the tempera- 
 
 
 
 ture of the water 
 
 
 
 from 3-3° to 212° F., 
 
 180.9 
 
 139,655 
 
 The latent heat:— 
 
 
 
 2. In the formation of 
 
 
 
 steam 
 
 892.935 
 
 689,346 
 
 3. In resisting the incum- 
 
 
 
 bent atmo spheric 
 
 
 
 pressure of 14.7 lbs. 
 
 
 
 per square inch, or 
 
 
 
 2116.4 lbs. per square 
 
 
 
 foot 
 
 72.265 
 
 55,788 
 
 
 965.2 
 
 7'l'i 1^^ 
 
 
 '^^^^^^ Jrrcl, Xt>*± 
 
 Total or constituent heat. . . 
 
 1146.1 
 
 884,789 
 
 Ques. What is the rule for finding the total heat in steam V 
 
 Ans. Multiply temperature or sensible heat of 
 the steam by .3 (1%) and add it to 1115°. 
 
SATURATED STEAM. 103 
 
 C^ues. Give an example. What is the total and latent 
 heat in steam that is 100 lbs. by the gauge ? 
 
 Ans. loo lbs. by the gauge is 115 gross, the 15 
 being, approximately, the weight of the atmosphere, 
 and 115 gross has (by Table page 99) 338° of heat, 
 hence, 
 
 338 X .3 = 101.4 + 1115° = 1216.4 = total heat. 
 
 338.0 = sensible heat 
 
 8781% latent heat* 
 
 Ques. What are the total units of heat in steam of 213° ? 
 Ans. 2i2°x. 3 = 63. 6+1115° = 1178.6° total heat 
 
 (^ues. What is the latent heat in this case ? 
 Ans. 1 1 78.6 = total heat. 
 
 212 == sensible heat. 
 
 966.6 = latent heat. 
 
 Ques. If the temperature of the feed water is known, what 
 will be the number of units of h>eat to each lb. of water 
 turned into steam ? Give illustration. 
 
 Ques. If the steam in the boiler be 270° and the feed water 
 be at 110° how^ many units of heat will it be necessary to add 
 to tliis water to turn a lb. of it into steam ? 
 
 Ans. 270 X. 3 = 81 4-1115 = 1 196, less feed water 
 110^1086. 
 
 * The small variation between the results in the examples and the 
 figures in the Table is caused by greater detail of calculation in one 
 more than the other. In the examples the air pressure is extended at 
 15 lbs. per square inch and in the Tables at l-t.T. 
 
 Let it be remembered that a Thermal unit (expressed by T. U.) is 
 the raising of 1 lb. of water 1 degree, and that the mechanical force 
 existing in each unit is 772 lbs. 
 
104 EiSrOiNEiEB''S EXAiUmATIONS. 
 
 Ques. "Which conducts heat best, dry steam or cloudy 
 steam ? 
 
 Ans. Dry steam is a poor conductor of heat as 
 compared with either liquid water or cloudy steam, 
 for after cloudy steam has received heat enough to 
 make it dry or nearly dry it receives additional heat 
 very slowly. 
 
 Ques. If a steam jacket is used, is the steam in the cylin- 
 der affected by the heat of the steam in the jacket ? 
 
 Ans. It is assumed that the steam in the cylinder 
 while expanding, receives just enough of heat from 
 the steam in the jacket to prevent any appreciable 
 part of it from condensing without superheating the 
 steam in the cylinder. 
 
 Ques. Is there any gain in using steam at 100 lbs. and by 
 expansion making the mean effective pressure 70 lbs. over, 
 using steam of 70 lbs. throughout the entire stroke ? 
 
 Ans. Using a cylinder with a volume of i cubic 
 foot, and an initial pressure of 70 lbs. continued 
 throughout the stroke, would be using, at each stroke, 
 a cubic foot of 70 lb. steam, or a weight of ,201 of a 
 pound. Now, should the initial pressure be 100 lbs., 
 a cut-off at ys stroke would give the desired mean 
 effective pressure of 70 lbs. and only use ^ cubic 
 feet of steam. Now, 100 lbs. steam weighs .264 lb. 
 per cubic foot ; ^ cu. ft. therefore = .099, so that 
 only .099 lb. would be used against .201 lb. of the 
 lever pressure steam, as in the first case. Thus by 
 working steam expansively you have a gain of 
 .20I — .099 ==.102 lb. at each ^ stroke. 
 
PUMPS. 105 
 
 PUMPS. 
 
 Upon the uniform operation of the pump depends the 
 safety and comfort of the engineer, owner and employees, 
 and indirectly of the success of the business with which ' ' the 
 plant " is connected. 
 
 Pumps now raise, convey and deliver water, beer, molasses, 
 acids, oils, and melted lead. They also handle such gases as 
 air, ammonia, lighting gas and even oxygen. 
 
 Pumps are made in various forms and sizes ; they vary in 
 design to suit their several uses, and are defined as rope, 
 chain, diaphram, jet, centrifugal, rotary, oscillating, cylin- 
 der. 
 
 It is with the last named class "with which the engineer 
 has principally to become expert. Cylinder pumps are of 
 two kinds, single acting and double acting. 
 
 The feed pump is used to supply the boiler, and it is 
 required to supply a quantity of water at least equal to that 
 evaporated and passed forward to the engine, together with 
 leakage at safety valve, &c. ; and to provide also for emer- 
 gencies it is usually made capable of supplying from 2 to 2^ 
 times this quantity. 
 
106 
 
 PUMPS. 
 
 The action of the pump may be explained as follows : Sup- 
 pose the plunger P at the bottom of its stroke, and the whole 
 interior of the pump to be full of air. When the plunger 
 rises the pressure of the suction valve S will be reduced, and 
 the air in the supply pipe will lift the valve and flow into the 
 barrel. The pressure of the air in the supply pipe is now less 
 than before, and accordingly the pressure on the external 
 surface of the wa- 
 ter forces water up 
 the pipe to such a 
 height as to make 
 the pressure inside 
 the pipe balance the 
 pressure outside. 
 When the plunger 
 returns the suction 
 valve is closed by 
 the pressure, and 
 the air is forced out 
 through the deliv- 
 ery valve D. Each 
 time the stroke of 
 the plunger is re- 
 peated, the water 
 will rise in the sup- 
 ply pipe until at last it reaches and fills the barrel. Now, 
 when the plunger returns, it forces water instead of air 
 through the delivery valve. 
 
 The height of the column of water which will balance the 
 pressure of the atmosphere is o4 ft. ; that is, a column wliose 
 
 -te 
 
 THE PUMP. 
 
PtJMPS. 107 
 
 weight is about 15 pounds per sq. in. In practice, however, 
 the supply can never be drawn from a depth greater than 
 about 25 ft. 
 
 The valves are prevented from rising above a certain height 
 by stops shown in the figure. The lift of a valve should not 
 exceed one-fourth of its diameter, for with this lift the whole 
 of the water which passes through the valve seating can 
 escape freely round the edge of the valve. Any further lift 
 is therefore unnecessary. 
 
 Air vessels A, V, are chambers fitted to pumps close to and 
 beyond the delivery valve. The air in the water collects in 
 this vessel and forms a cushion or spring which enables the 
 water to be delivered in a steady stream. 
 
 Ques. What is a single acting pump ? 
 
 Ans. A single acting pump does its work through 
 one end of the cylinder. 
 
 Ques. What is a double acting pump ? 
 
 Ans. It is an engine and pump combined ; in 
 double acting pumps the motion of the piston in one 
 direction causes an inflow of water, and a discharge 
 at the same time, in the other ; and on the return 
 stroke the action is renewed as the discharge end 
 becomes the suction end. The pump is thus double 
 acting. 
 
 Qnes. In a steair pump what are the two ends called ? 
 
 Ans. The steam-end, which is a complete steam 
 engine, and the water-end, into which the water is 
 drawn, and from which it is discharged. 
 
108 ENGINEERS' EXAMINATIONS. 
 
 Ques. What is the connection between these ends — if any ? 
 
 Ans. The water and steam ends are operated by 
 a single rod, called the piston rod, which extends 
 through from one end to the other — a pump so 
 operated is a direct acting steam pump. 
 
 Ques. What is the force against which a pump works 
 aside from the boiler pressure ? 
 
 Ans. Gravity, or the attraction of the earth, 
 which prevents the water from being lifted. This is 
 shown in the fact that water can be led, or trailed 
 an immense distance, limited only by the friction, 
 by a pump. 
 
 Ques. What is the difference between a suction and a 
 discharge valve ? 
 
 Ans. The suction valve prevents the return of 
 the water after it has entered the cylinder, and the 
 discharge valve permits the outward passage of the 
 water but does not allow its return. 
 
 Ques. Is it true that water is raised by suction ? 
 
 Ans. No. Water is raised by pressure of air on 
 the water outside the pump. The piston of the 
 pump exhausts the air and the unbalanced weight of 
 water causes it to rise within the pump or pipes 
 supplying the pump. 
 
 Ques. What is the limit of this lift 7 
 
 Ans. About ^2 feet, because water of one inch 
 area weighs 14^5 lbs., which is the weight of one 
 
QUESTIONS AND ANSWERS. 109 
 
 'nch of air, at the sea level. Pumps must be in 
 good order to lift 33 feet, and all pipes and valves 
 must be perfectly air tight ; pumps will give better 
 satisfaction lifting from 22 to 25 feet. 
 
 Qiies. In designing or purchasing pumps what is the safe 
 rule as to capacity ? 
 
 Ans. One should be selected capable of deliver- 
 ing one cubic foot of water per horse power per 
 hour ; or say, three pounds of water for each square 
 foot of heating surface. 
 
 Ques. Why will not a pump lift hot water ? 
 
 . Ans. Because the vapor from the hot water fills 
 the vacuum as fast as it is made by the piston and 
 destroys its force, hence, no pump, however good, 
 will lift hot water. 
 
 Qiies. What is the best method of getting around this 
 difficulty ? 
 
 Ans. The pump should be placed below the 
 supply, so that the water may flow into the valve 
 chamber. 
 
 Ques. What is the most necessary condition for the satis- 
 factory operation of a pump ? 
 
 Ans. A full and steady supply of water. The 
 pipe connections should in no case be smaller than 
 the openings in the pump, and the suction lift and 
 delivery pipes should be as straight and smooth on 
 the inside as possible. 
 
110 ENGINEERS' EXAMINATIONS. 
 
 Ques. What is the advantage of the suction chamber ? 
 
 Ans. It prevents pounding — makes the action of 
 the pump easy and uniform and enables the pump 
 barrel to fill when the speed is high. 
 
 (^ties. How should pumps be left in cold weather ? 
 
 Ans. Pumps should always be drained in cold 
 weather, as freezing of water in pipes or cylinders is 
 sure to burst them. Engineers should therefore be 
 careful, and open the drip plugs or cocks, which are 
 provided on all pumps for draining them. 
 
 Ques. What directions would you give as to setting up a 
 pump ? 
 
 Ans. Use as few bends and valves as possible, 
 and run every pipe in as direct line as practicable, 
 and where convenient use full round bends rather 
 than elbows, for valves, returns and elbows increase 
 friction more rapidly than length of pipe ; never use 
 pipes too small in diameter ; in long pipes this 
 should be increased to allow for increased friction, 
 especially in suction pipes. 
 
 Ques. In ordering a pump what is it for the interest of the 
 purchaser for the builder to know ? 
 
 Ans. ist. For what purpose is the pump to be 
 used, and the average pressure of steam ? 
 
 2d. What is the liquid to be pumped, and is it hot 
 or cold, clear or gritty, fresh, salt or acidulous? 
 
 3d. What is the maximum quantity to be pumped 
 per hour ? 
 
QUESTIONS AND ANSWERS. Ill 
 
 4th. To what height is the liquid to be lifted by- 
 suction, also the height of discharge ? What are the 
 length and diameter of the suction and discharge 
 pipes, and the number of elbows or turns ? 
 
 Qucs. Granted motion to the piston or plunger of a pump 
 what is the only cause that makes it fail with an abundance 
 of water ? 
 
 Ans. A pump fails because it leaks — there can 
 be no other reason, and the leak should be found 
 and repaired. Leaky valves are common and should 
 be ground ; leaky plungers are frequent and should 
 be re-turned in a lathe ; leaky pistons sometimes 
 exist and they should be repaired. The rod must be 
 straight as far in as the packing and that must be 
 kept free from dirt and sediment. 
 
 Ques. What should long suction pipes be provided with ? 
 
 Ans. A foot valve, just above the strainer, in the 
 well or pit. 
 
 Ques. What are direct acting steam pumps ? 
 
 Ans. These have a single cylinder non-expanding 
 and in larger sizes with double cylinders on the 
 compound principle. These pumps may be divided 
 into two classes ; those having the valve gear on the 
 outside where it can be seen, and those having the 
 valve gear inside, no moving parts being visible 
 when the pump is in operation except the piston 
 rod. 
 
 Ques. What are direct acting duplex pumps ? 
 
113 ENGINEERS' EXAMINATIONS. 
 
 Ans. These are two steam pumps placed side by 
 side, so combined that the slide valve of each 
 cylinder gets its motion from the opposite piston 
 rod through a lever and rockshaft. The single 
 direct acting and the duplex direct acting pumps 
 are almost always double acting pumps, having the 
 steam piston and the water piston at the two ends 
 of the same rod. Therefore the steam pressure 
 exerted upon the steam piston will be exerted upon 
 the water piston direct. 
 
 (Jues. What are pumping engines ? 
 
 Ans. It has become customary to apply the term 
 pumping engines to large reciprocating pumps used 
 for supplying cities and towns with water,- draining 
 lakes and marshes, and other purposes, although 
 strictly speaking any steam pump with its motor 
 arranged in one machine is a pumping engine. 
 
 Ques. "Which should have the larger area, the steam pis- 
 ton or water piston of the steam pump ? 
 
 Ans. The steam piston should have about 2^ 
 times the area of the water piston. There being no 
 mechanical purchase in favor of the steam piston, it 
 must have the greater area of the two, otherwise 
 the pressure on the water piston would equal the 
 pressure on the steampiston and the pump would 
 refuse to work. For this reason all boiler pumps 
 have larger steam pistons than water pistons. 
 
 Ques. What rule would you give for area of steam piston ? 
 Ans. Multiply area of water piston by 2.75. 
 
QUESTIONS AND ANSyVERS. 113 
 
 Qlies. How woiild you find the capacity of a water 
 cylinder of a steam pump in gallons ? 
 
 Ans. Multiply the area in inches by the length 
 of stroke (this gives the capacity in cubic inches). 
 Next divide by 231 (which is the cubical contents 
 of a U. S. gallon) and the product is the capacity in 
 U. S. gallons. 
 
 Ques. What is the rule for finding quantity of water 
 pumped in one minute running at 100 feet of piston speed 
 per minute ? 
 
 Ans. Square the diameter of the water cylinder 
 in inches and multiply by 4. The answer will be in 
 gallons. 
 
 (^ues. How do you find the horse-power necessary to 
 pump w^ater to a given height ? 
 
 Ans. Multiply the total weight of the water in 
 pounds by the height in feet and divide the product 
 by 33,000. 
 
 Ques. How do you find the pressure in lbs., per square 
 inch, of a column of water ? 
 
 Ans. Multiply the height of the column of water 
 in feet by .434. 
 
 Ques. What is the rule for finding the water capacity of 
 a steam pump per hour ? 
 
 Ans. ist. Find the capacity of the pump in cubic 
 inches, by multiplying the area by the inches in 
 Strokes, and by the fraction it is full. 
 
114 ENGINEERS' EXAMINATIONS. 
 
 2d. Find the cubic inches of water pumped per 
 hour, by multiplying the contents of the pump by 
 the strokes per minute and by 60, representing the 
 minutes in an hour. 
 
 3d. Find the number of the cubic feet of water by 
 dividing the cubic inches by 1,728, 
 
 Ques. In these rules have you made any allowance for 
 
 " slippage " and friction ? 
 
 Ans. No. 
 
 Ques. What must every feed pump be designed to do ? 
 
 Ans. It must provide not only the water really 
 needed for the work, but a large percentage addi- 
 tional to cover waste due to priming, condensation 
 in the pipes, etc. 
 
 Ques. Give an idea of amount of slippage ? 
 
 Ans. In well designed and well constructed 
 steam pumps the "slippage" will be one-tenth and 
 an allowance of one-quarter will be safe for the 
 friction ; but if the pump is old or badly designed 
 or if the pump is working against a very high or a 
 very low lift the net loss should be increased to 
 twice the percentages given. 
 
 Ques. Can you give approximate rule for size of pipes for 
 steam ? 
 
 Ans. For the steam pipe divide the area of steam 
 piston by 64, 
 
QUESTIONS AND ANSWERS. 115 
 
 For the exhaust pipe divide the area of steam 
 piston by 32. 
 
 For the discharge pipe divide the area of plunger 
 by 3- 
 
 For the suction pipe divide the area of plunger 
 by 2. 
 
 But as the sizes of piping are of standard sizes, 
 sizes can only be approximated, preference being 
 given to the next size larger than the figures call for. 
 
 Ques. When pressure per square inch is shown by the 
 guage, which is the greater pressure, that of water or steam? 
 
 Ans. There is no difference between the intensity 
 of steam pressure and water pressure, a pound of 
 pressure is a pound whether of steam or water. 
 
 Oues. What are pump valves made of ? 
 
 Ans. They are made of brass, hard rubber, soft 
 rubber, vulcanized fibre and wood. 
 
 Ones. What is to be said as to their size and " lift " ? 
 Ans. The valves should be larger than the pipe, 
 enough so as to give a clear waterway, the same area 
 as the suction pipes. The lift of the valves should 
 be as little as possible without causing too much 
 frictional resistance to the water. 
 
 Ques. For leakage of water and steam priming, blowing 
 off, loss by safety valve, etc., how much water for a station- 
 ary engine should be provided ? 
 
116 ENGINEER'S EXAMINATIONS. 
 
 Ans. From double to two and one-half times the 
 net feed water required by the engines. 
 
 (^iies. How much should be allowed in marine engines ? 
 
 Ans. To provide for the discharge of the brine, 
 from three to four times of the net feed water should 
 be provided. 
 
 Ques. Of what is water composed and in what proper 
 tions? 
 
 Ans. Water is composed of one volume of 
 hydrogen to two of oxygen. 
 
 Ques. What are the cubic contents and weight of a cubic 
 foot of water ? 
 
 Ans. I cubic foot equals 7^ gallons (1,728 cubic 
 inches) and weighs 62^ lbs. A gallon thus has 231 
 cubic inches and weighs 8^ lbs. 
 
 Ques. What is the rule for finding the water capacity of 
 the horizontal steam boiler 1 
 
 Ans. I. Multiply two-thirds of the area of the 
 head, in inches, by the length of the boiler in inches. 
 
 2. Deduct the area of a single tube multiplied by 
 the number in the boiler, multiplied by the length 
 in inches. 
 
 3. Divide by 231 to reduce the answer to gallons. 
 
QUESTIONS AND ANSWERS. 11? 
 
 THE INJECTOR OR INSPIRATOR. 
 
 This boiler fixture was an invention of Gifford, and is one 
 of the most peculiar and interesting appliances connected 
 with the steam plant. 
 
 It is simply an instrument for allowing steam to rush from 
 a boiler, and to suck up and mix with itself a stream of cold 
 water, by which it is condensed, and to which it imparts so 
 much of its own velocity, that the combined mass of water 
 and condensed steam enters into and feeds the boiler. 
 
 Injectors are used also to pump out cisterns and drain 
 basins and have even been used to pump out mines. 
 
 Questions and Answers Relating to the 
 Steam Injector. 
 
 Ques. What is the main difference between the steam 
 pump and the injector ? 
 
 Ans. The pump has moving parts and is a regu- 
 lar machine, while the injector has no moving 
 mechanism whatever. 
 
 Ques. Whence comes the power, used in forcing water 
 into the boiler by an injector ? 
 
118 ENGIJSrEERS' EXAMltfA'nOJSIii. 
 
 Ans. To the difference in the velocity of the 
 escaping steam from a boiler under pressure and the 
 velocity acquired by water from the same boiler and 
 under the same pressure and at the same time. 
 
 Ques. About what is the difference in the speed of tL:6 
 two? 
 
 Ans. The steam has a velocity of sixteen or 
 eighteen times that of the water — this varies with 
 the pressure. 
 
 Ques. How should the instrument be connected ? 
 
 Ans. It should be so placed that it will take 
 steam from the highest point in the boiler. A valve 
 should be put in the steam pipe just above the 
 injector and a check and globe valve between it and 
 the boiler, also a globe valve in the supply pipe ; if 
 the feed is delivered through a heater, place a check 
 between it and the injector. It is better to have the 
 suction pipe one size larger than the connection 
 with the boiler, especially in case of a high lift. 
 
 Ques. What are essential to the snccessful operation of 
 the instrument V 
 
 Ans. The suction pipe should oe absolutely air. 
 tight ; the lift should not exceed 25 feet with a 
 temperature of about no degrees and not more 
 than 140 degrees for a low lift, 
 
 Ques. Will the injector work if the water supplied to it is 
 too hot '? 
 
QUESTIONS jLNJD a.kswi:rs. 119 
 
 Ans. No. Because the colder the water the 
 quicker and more thoroughly is the steam turned 
 into water of condensation ready to join in the flow 
 towards the boiler. 
 
 (Jues. Dvjes the injector "suck up" or lift the water that 
 it forces into the boiler ? 
 
 Ans. No more than a pump does ; for both appa- 
 ratuses simply remove the air from the supply pipes 
 and the weight of the atmosphere pushes the water 
 forward. 
 
 Ques. What are injector-nozzles ? 
 
 Ans. They are tubes with ends rounded to 
 receive and deliver the fluids with the least possible 
 loss by friction and eddies. 
 
 Ques. What are double injectors ? 
 
 Ans. They are those in which the delivery from 
 one injector is made the supply of the second. The 
 double injector makes use of two sets of nozzles, the 
 "lifter" and "forcer." The lifter draws the water 
 from the reservoir and delivers it to the forcer, 
 which sends it into the boiler. 
 
 Ques. What is the exliaust steam injector ? 
 Ans. It is different from others in that it uses 
 the exhaust steam from a non-condensing engine. 
 
 Ques. What has been tlie objection to tlie greater adoption 
 of this form of injector ? 
 
 Ans. It carries over into the boiler the waste 
 steam from the cylinder. 
 
120 ENGINEERS' EXAMINATIONS. 
 
 THE INDICATOR. 
 
 This device, inv^ented by James Watt more than a century 
 ago, is an ingenious tell-tale of what goes on in the steam- 
 cylinder. A knowledge of its operation is necessary to 
 obtain a high-grade license. 
 
 All indicators are practically of the same construction and 
 act upon the same principle. Each consists of a small 
 cylinder accurately bored out and fitted with a piston capable 
 of working in the cylinder with Uttle or no friction ; the pis- 
 ton rod is attached to a pair of light levers, at the end of one 
 of which is carried a pencil designed to move perpendicu- 
 larly. The motion of the piston in the cyUnder is |f of an 
 inch and the area of the piston is exactly 3^ square inch. 
 
 The pressure of the steam is recorded by the pencil at all 
 points of the stroke as the piston moves to and fro, on a 
 piece of paper secured to a revolving drum. The motion of 
 the piston is controlled by springs of known tension, several 
 of which are furnished with each instrument ; each spring is 
 marked to show at what boiler pressure of steam it is to be 
 used. 
 
 The only absolute information any indicator can convey, 
 whatever its form, is the pressure in the cylinder of the 
 engine ; all the other information to be had from it comes 
 
QUESTIONS AND ANSWERS. I2l 
 
 through a process of reasoning based upon experience and 
 observation. 
 
 In order that the diagram should be correct it is essential, 
 first, that the motion of the drum and paper shall coincide 
 exactly with that of the engine-piston, and that the motion 
 of the pencil shall also correspond with the other motions 
 described. 
 
 Questions and Answers Relating to the 
 Indicator. 
 
 Ques. What is an indicator card ? 
 
 Ans. It is a paper wound round the cylinder of 
 the indicator upon which the pencil has drawn the 
 lines indicating the work done by the steam in the 
 cylinder. The extreme length of the diagram may 
 be 5^ inches. 
 
 Ques. What is the steam-line ? 
 
 Ans. It is the line on the card which shows the 
 place of admission to beginning of cut-off. 
 
 Ques. What is the exhaust line ? 
 
 Ans. It is that part of the diagram which shows 
 the point of exhaust. 
 
 Ques. What is the expansion line ? 
 
 Ans. It is that part showing the curve of 
 expansion; /. e., the movement between the cut off 
 and the exhaust. 
 
122 ENOmWEnS' EXAMINATIONS. 
 
 (|ues. What base line is always assumed in figuring the 
 indicator card ? 
 
 Ans. All figures are made from absolute vacuum, 
 or 141V lbs. per sq. inch below atmospheric pressure. 
 
 Ques. Why? 
 
 Ans. For, from the line of absolute vacuum are 
 made up all tables of weight, volume, expansion 
 and all other properties of steam. 
 
 Ques. What four points does an indicator show ? 
 Ans. Highest and lowest pressure, cut-off and 
 lead. 
 
 Ques. How can you determine whether the steam is 
 
 "wire-drawn " ? 
 
 Ans. If the steam is " wire-drawn " the steam 
 line will fall as the piston advances. 
 
 (Jues. What is done when steam is cut-off at 6 inches ? 
 
 Ans. When the piston has travelled 6 inches the 
 valve closes, cutting off the live steam, and the 
 remainder of the work in the cylinder is done by 
 the expansion of the steam previously admitted. 
 
 Ques. What do you understand by the number of an 
 indicator spring ? 
 
 Ans. The number marked on a spring (several 
 of which are furnished with each indicator) is 
 designed to show the number of lbs. steam pressure 
 on the boiler at which it is to be used : thus a 30 lb. 
 
QUESTiOH^S AKn ANSVTWRS. l^B 
 
 spring is one in which a pressure of 30 lbs. will 
 cause the piston inside the indicator to rise one 
 inch above the atmospheric line of the diagram.* 
 
 Ques. What is an indicator diagram ? 
 
 Ans. It is the figure drawn by the pencil attached 
 to the indicator from which the mean effective 
 pressure in the cylinder is calculated. 
 
 Ques. How is this done ? 
 
 Ans. By first dividing the diagram into ten equal 
 spaces by drawing perpendicular lines to the atmos- 
 pheric line called ordinates. Any number of ordi- 
 nates may be used but it is customary to use 10. 
 
 2. The two end ordinates should be only half the 
 distance from the ends of the diagram that they are 
 from the next ordinate, because the ordinate is the 
 middle of the space it occupies. 
 
 3. The ordinates being drawn their lengths are 
 added together and the sum so obtained is divided 
 by the number (10) which gives the average heighth. 
 
 4. If a 30 lb. spring has been used and the average 
 heighth of the ordinates is i^ inches, then the 
 
 * The strength of the spring is so adjusted as to cause the diagram 
 tobeahout2}4 inches high, let the steam pressure be what it may. 
 The following are the scales of springs to he used in the Thompson 
 Indicator : 
 
 Scale of Used for pressure above atmosphere 
 
 Spring- if not more than 
 
 15 lbs. ... 31 lbs. per sq. in. 
 80 " ... 38 " " " " 
 
 80 " ... 94 » '' " " 
 60 ** . . . 143 " " " " 
 
124 ENOTNEERS' EXAMINATIONS. 
 
 average pressure of steam in the cylinder shown by 
 the diagram is 45 lbs. 
 
 Ques. Having found the average pressure in the cylinder, 
 how do you proceed to get the indicated horse power (I. H. P.) ? 
 
 Ans. By multiplying the travel of the piston in 
 feet and the area of the piston in inches; 2, multi- 
 plying the product by the mean average pressure in 
 lbs. — in the case given ; 45 lbs. — and dividing by 
 33,000. 
 
 Ques. What have you to say as to calculating, by the 
 indicator, the amount of water and steam used from the 
 boiler ? 
 
 Ans. Experience shows that the full amount of 
 water used cannot be accounted for, owing to its 
 being unduly saturated, the cooling of the cylinder, 
 etc., hence the calculations made are unsatisfactory. 
 
 Ques. Is there an easy way of getting the lengths of the 
 ordinates ? 
 
 Ans. Yes. Take a long strip of paper, say half 
 an inch wide and 10 or 20 inches long, according to 
 the nature of the card, mark a starting place on the 
 edge near one end; then lay the strip of paper along 
 the first dotted line, and mark off the length of that 
 line ; then lay it on the second space so as to add 
 the length of the second line to the first line; and so 
 on until the tenth (dotted line) ordinate is added, 
 the whole being in one length, end to end. 
 
 Now take a rule and read off how many inches 
 there are in the whole length, and divide them by ten. 
 
QUESTIONS AND ANSWERS. 135 
 
 Qiies. What instrument has been invented and introduced 
 to get the mean effective pressure as shown by a diagram ? 
 
 Ans. A planimeter. No skill or mathematical 
 knowledge are necessary to use this instrument. 
 The readings taken from a counter on the instru- 
 ment give the area of the enclosed figure. 
 
 Qiies. What is the difference between the Indicated Horse 
 Power (I. H. P.) and the Effective Horse Power (E. H. P.)? 
 
 Ans. The effective horse power is the indicated 
 horse power less the engine friction ; it is always 
 less from the fact that the engine itself absorbs 
 power. 
 
 (^ues. What proportion of the indicated power does the 
 engine consume ? 
 
 Ans. With well constructed engines and every- 
 thing in good working order it is probably under 
 ten per cent. — but with the ordinary unbalanced 
 slide valves and bad construction one-third of the 
 power is wasted. 
 
 Ques. Does a correct curve always show an economical 
 
 engine ? 
 
 Ans. No, because a defective leakage may be 
 the same on both sides — the leakage out may balance 
 the leakage in — hence it must be carefully assured 
 that the piston and valves are tight. 
 
 Ques. Does a defective diagram always indicate trouble ? 
 
 Ans. Yes, a diagram with an incorrect curve 
 necessarily and infallibly shows a wasteful engine. 
 
126 ENGINEERS' EXAMINATIONS. 
 
 ELECTRICITY FOR ENGINEERS. 
 
 The latest developments of engineering are without a 
 doubt along electric lines, and, in issuing a license for a 
 steam plant where there is an electrical apparatus, the Ex- 
 aminer will insist upon some knowledge and practical ex- 
 perience in industrial electricity — and the devices employed 
 to utilize it before granting a license. 
 
 The Electric current (so-called) is produced by a machine 
 known as a Dynamo or Electric Generator ; this might be 
 called the Steam Engine of Electricity as it simply transmits 
 or carries along the power, produced elsewhere, to its spect- 
 fied work. 
 
 It is with the Dynamo that the Licensed engineer and \us 
 assistants has primarily to do, and it is necessary that he have 
 a mastery of it — in the same degree that he has of his engine. 
 It is true that in the Power Stations of Electric Railways 
 and other large plants that Electricians, so ranked are con- 
 stantly on watch, but it is generally true tha^^ the Engineer 
 has charge of the Electric apparatus. 
 
 Next to the Dynamo the Engineer must be informed as to 
 the Laws of the Transmission of the Electric Current — in 
 practical language he must understand " Wiring. " 
 
 The recent great advance in the practical developnaent of 
 Electricity has come from the discovery of the Electric Motor 
 
QUESTIONS AND ANSWERS. 137 
 
 — which is simply a Dynarao reversed — while the Dynamo is 
 run by a belt or other mechanical means, the Motor is run 
 by the electric current. A practical acquaintance with one 
 answers for both the Dynamo and the Motor, although there 
 are some points of difference necessary to be known. 
 
 What is electricity is a question often asked, but w^hich 
 has never yet been satisfactorily answered. It is one of the 
 unexplained existences which, like latent heat, are known to 
 be, but aside from their mighty and beneficial accomplish- 
 nients might as w^ell remain unknown. 
 
 How electricity is "gathered" and how it is utilized in 
 some of the many machines now in use is the limit of neces- 
 sary knowledge concerning it. 
 
 It is well to remember at the beginning that magnetism is 
 almost indentical with electricity, and that the way in which 
 a small magnet will attract and hold a bit of iron or steel (a 
 tack or nail) is the A B C of the science. Next, that iron or 
 steel are the principal metals (with copper wire) with which 
 ine greatest as well as the least of the electrical problems 
 are worked out to a commercial and industrial success. 
 
 Questions and Answers Relating to Electric- 
 ity and Electric Machines. 
 
 (^ues. What is an electric current ? 
 
 Ans. It is something which seems to flow along 
 Ox'- through the conducting wires ; although not 
 known as to its nature it is freely called the electric 
 current. 
 
ENGINEERS' EXA31INATI0NS. 
 
 Ques. How many kinds of electricity are there ? 
 
 Ans. One — although it is spoken of and treated 
 
 as two, positive and negative. 
 
 Ques. How are tliese designated ? 
 
 Ans. By the plus sign + for positive and the 
 negative sign — for the negative electricity. These 
 signs are very useful in designating the two, 
 
 Ques. How do these stand in relation to each other ? 
 
 Ans. It is said that + electricity attracts — 
 electricity, and that — electricity attracts + and tne 
 contrary, -|- repels +, — repels — . 
 
 Ques. How do these currents flow ? 
 
 Ans. Positive (+) electricity and ( — ) electricity 
 mean but a difference in pressure, always flowing 
 from + to — as steam always flows through the 
 steam pipe, engine and exhaust and never backward. 
 It is impossible to generate a current of negative ( — ) 
 electricity of a higher pressure than the (-J-) positive 
 current, 
 
 Ques. What is a conductor ? 
 
 Ans. Anything that will allow the electric cur- 
 rent to flow freely through it. All the lines (wires) 
 carrying electricity are conductors, hence any- 
 thing which allows the free passage of electricity is 
 a conductor, and anything which prevents the 
 passage of electricity is a non-conductor. 
 
QUESTIONS AND ANSWERS. 129 
 
 Ques. Which is the most important ? 
 
 Ans. It is just as necessary in practical work to 
 have good non-conductors as it is to have good 
 conductors.* 
 
 (^iies. Name some of the conductors. 
 
 Ans. The ground is a good conductor, vi^hich 
 fact often causes great "trouble." Water is a 
 conductor, and if the wires and their supports are 
 wet, and if there are any conducting substances that 
 will allow the passage of current to the ground, 
 there is trouble again. Other conductors are silver, 
 copper, iron, etc.f 
 
 Ques. Name some non-conductors ? 
 
 Ans. Dry air, glass, silk, asbestos, woolen and 
 cotton cloth, dry paper, dry wood, oils. 
 
 Ques. What substances are generally used for non-con 
 ductors ? 
 
 Ans. Cotton or silk, coated with paint, varnish 
 or asphaltum ; the cotton and silk are the non- 
 conductors, and the varnish, etc., are put over all to 
 keep away the moisture. 
 
 * All substances will allow of the passage of some electricity, but 
 as there are substances that offer a very strong resistance to its pass- 
 age they are generally called insulators, or simply non-conductors. 
 
 t Silver is six times as good a conductor as iron, that is, if you take 
 a silver wire and an iron wire the current will pass through the silver 
 wire six times as easy as through iron. Lead will only conduct one- 
 eleventh as well as silver. 
 
130 ENGINEERS' EXAMINATIONS. 
 
 Ques. What is one of the most important points in keeping 
 up electric machines and circuits ? 
 
 Ans. To keep the circuits well insulated, and to 
 allow no accumulation of oil and dirt around the 
 machines to form a conducting substance. Lamps 
 and dynamos must also be kept clean so that they 
 work freely. Gas, moisture, and steam are to be 
 watched for, as they all destroy the necessary insu- 
 lation. 
 
 Qiies. What is a dynamo-electric machine ? 
 
 Ans. It is a machine driven by power, usually by 
 steam or water, used to convert mechanical power 
 into electrical energy. 
 
 Ques. Describe, generally, the construction of a dyTiamo. 
 
 Ans. There are various styles of dynamos, but 
 they are all built upon similar principles. First, 
 there is the magnet core, usually made of wrought 
 iron ; second, around the core are wound field coils 
 — the field coil is copper wire generally insulated 
 with soft cotton thread and double-wound ; third, 
 pole pieces, usually made of cast iron, into which 
 the magnetic core is cast ; the round space between 
 the pole pieces is the magnetic field — so called 
 because it is there that the lines of magnetic force 
 cross from one pole to the other, and where the arm- 
 ature is placed ; the pole pieces are united by, fifth, 
 a "yoke," which completes the magnetic current; 
 this is practically an electro magnet of the horse- 
 ghoe form, with the wire wound on near the poles. 
 
QUESTIONS AND ANSWERS. 131 
 
 (^ues. What is the meaning of the term insulated ? 
 
 Ans. This means removed from the sensation of 
 touch, handling or feeling — rendered insensible to 
 touch, 
 
 Ques. What is the object of insulating the wire of electro 
 magnets ? 
 
 Ans. So as to form lines of travel for the mag- 
 netic force. 
 
 Ques. What would be the effect, if, through imperfect 
 insulation, the wires of the magnetic coil came into contact 
 at some point or other ? 
 
 Ans. It means so much loss, and if the insula- 
 tion is too imperfect the whole circuit will have to 
 be abandoned or newly insulated. 
 
 Ques. Is there any difference in the names of the poles in 
 pei-manent and electro magnets ? 
 
 Ans. In a magnet the pole into which the lines 
 of force are assumed to enter is called the south 
 pole ; the pole from which they are assumed to 
 emerge is called the north pole — in other words the 
 aorth pole is positive and the south pole negative. 
 
 (^ues. What is a permanent magnet '? 
 
 Ans. It is a bar of U-shaped steel which con- 
 iinues magnetized for an indefinitely long time. 
 
 Ques. What is an electro magnet ? 
 
 Ans. It is a body of iron which becomes magne- 
 tized by the electric current passing around it 
 
132 ENGINEERS' EXAMINATIONS. 
 
 conducted by insulated wires — it is the opposite of a 
 permanent magnet because upon stopping the 
 machine the magnetic condition ceases. 
 
 Ques. What is a switch ? 
 
 Ans. A switch is a device used to make or break 
 a circuit — the switch is so arranged that the hand 
 will start it, while a powerful spring throws the 
 switch open or closes it immediately. 
 
 Ques. What is a brush ? 
 
 Ans. This consists of a quantity of straight 
 copper wires laid side by side, soldered together at 
 one end and held in a suitable clamp ; two layers of 
 wires are often thus united in a single brush. 
 
 Brushes are also made of broad strips of springy 
 copper, slit for a short distance, so as to touch at. 
 several points. 
 
 Ques. What is the object of slitting the brush ? 
 
 Ans. The subdividing of the spark at the 
 contact. 
 
 Ques. What rule do you consider important relating to 
 the brushes ? 
 
 Ans. A brush should never be lifted off the 
 commutator while tho dynamo is running. 
 
 (^ues. When do the brushes cause "flashing " ? 
 
 Ans. When they are out of position, too far 
 ahead or too far back or not set directly opposite 
 each other ; if the brushes do not have sufficient 
 contact, a machine will frequently flash. 
 
QUESTIONS AND ANSWEM 133 
 
 Ques. What is the use of the commutator ? 
 
 Ans. The commutator or collector of a dynamo 
 is used for changing the alternating currents, as 
 produced in the armature, to continuous currents as 
 delivered to the lines. The commutator transfers 
 these currents, as they are formed, to the brushes, 
 which convey them to the lines continuously in one 
 direction. 
 
 (J lies. What is the commutator ? 
 
 Ans. In general, a cylinder made up of alternate 
 sections of conducting and non-conducting substan- 
 ces, running parallel with the shaft of the machine 
 upon which it turns. 
 
 Ques. What may be said about the trouble caused by the 
 dynamo ? 
 
 Ans. In the commutator and brushes will be 
 found the greater part of the difficulties that the 
 engineer in charge of the dynamo has to contend 
 with in his electric plant. 
 
 Ques. What is the difference between an incandescent 
 hght and an arc light ? 
 
 Ans. The incandescent* light is produced by 
 passing electricity through a carbon ribbon or fila- 
 ment confined in a vacuum ; an arc light is produced 
 by passing electricity through two carbon pencils 
 slightly separated, in open air. 
 
 * Incandescent means white. The electricity passing between the 
 points forms an " arc " or curved line. Hence the name, arc light. 
 
134 tlNOlN^lEnS' tlXAMmATlONS. 
 
 Questions and Answers Relating to Gravity 
 and Strength of Materials. 
 
 Ques. What is gravity ? 
 
 Ans. It is an unexplained force which draws 
 every particle of matter toward every other particle. 
 It extends to all known bodies in the universe, from 
 the smallest to the greatest. 
 
 Qiies. What is specific gravity ? 
 
 Ans. Every substance in nature has a weight 
 specific — or peculiar- — to itself. For example, pine 
 wood has a certain weight and cast-iron has another 
 certain weight, hence, the specific gravity of a body 
 is its weigTit compared with the weight of another 
 body taken as a standard. 
 
 Ques. What is the accepted standard for all solids and 
 liquids ? 
 
 Ans. Water. 
 
 Ques. What is the standard of comparison for all gases ? 
 Ans. Air. 
 
 Ques. When we say that the specfic gravity of iron 
 (wrought) is 7. 688, what do we mean ? 
 
 Ans. That it is seven times as heavy as water 
 
 and Ttnnr over.* 
 
 * The heaviest of all known substances is platinum, whose specific 
 gravity is 22, water 1 ; and the lightest of all weighable bodies is 
 hydrogen gas, whose specific gravity is iVlfffi common air being 1, but 
 air is 818 lighter than water. Hence, by calculation, it will be found 
 thut platinum is 247,000 times heavier than hydrogen, and a wide ranga 
 is allowed to the various bodies which lie between these extremes. 
 
QUESTIONS AND ANSWERS. 135 
 
 Ones. How may weight be defined ? What is it ? 
 
 Ans. The weight of a body is the force it exerts 
 in consequence of its gravity. We weigh a body by 
 measuring the force required to hold it back, or to 
 keep it from descending, hence weights are nothing 
 more than measures of the force of gravity in differ- 
 ent bodies. 
 
 Ques. What is that principle which holds bodies together 
 called ? 
 
 Ans. It is the strength of cohesion ; this is the 
 power residing in the minute particles of matter, 
 called molecules, to cling together. 
 
 Ques. Name four ways in which this cohesion may be 
 overcome in a bar of iron or piece of timber, and the common 
 names of the forces used ? 
 
 Ans. I. The bar may be pulled asunder; resist- 
 ance to this force is called tensile strength. 
 
 2. The iron may be crushed in the direction of its 
 length. This is direct thrust or compression, and 
 the resistance to it is called the crushing strength. 
 
 3. The bar may be bent or broken from the direc- 
 tion of the middle or side. This is transverse strain 
 or flexion, and resistance to it is called transverse 
 strength. 
 
 4. The bar may be twisted off ; this is torsion; 
 resistance to it is tortional stretigth. 
 
 Ques. Define stress and strain. 
 
 Ans. Any bending or breaking pressure is a 
 stress ; its effect on the piece is a strain ; hence the 
 
136 ENGINEERS' EXAMINATIONS. 
 
 Strength of a solid piece or body is the total resist- 
 ance it can oppose to strain in that direction. 
 
 Ques. What is the Hydrometer ? 
 
 Ans. It is an instrument constructed for the 
 especial purpose of ascertaining the specific gravities 
 of liquids. 
 
 (Jues. How may the specific gravity of solids be found ? 
 
 Ans. Advantage may be taken of the important 
 fact that when a body is wholly immersed in water, 
 it displaces a bulk of that liquid exactly equal to its 
 own, hence the difference of its weight in water 
 from that of its weight in air must be the weight ol 
 an equal bulk of water. 
 
 (Jues. What is a Salinometer ? 
 
 Ans. It is a glass or metal instrument, by means 
 of which the density of water is ascertained. In 
 plain language it is a salt measure or hydrometer. 
 
 Ques. What is the amount of salt held in solution in sea 
 water? 
 
 Ans. One thirty-third (sV). This quantity is 
 called one degree, and if the watci" of a marine 
 boiler tested by the instrument shows ^, it is 
 expressed by saying " two degrees ", if ^, then 
 three degrees, etc. 
 
 (^ues. How are the Salinometers graduated ? 
 
 Ans. Some into 33ds, and some into 32ds, each, 
 representing about five ounces of salt to a gallon of 
 water.* 
 
 ♦ Note, L e., each. 33d has 502 salt. •;,% has 1,002, -fg has 1.B02, etc 
 
QUESTIONS AND ANSWERS. 
 
 137 
 
 Qiies. 
 
 used? 
 
 In the use of the SaUnonieter where should care be 
 
 Ans. They should be used on water taken from 
 the boiler almost as soon as it ceases to boil, as 200° 
 is the usual temperature at which these instruments 
 are tested, and as the density of fluids vary accord- 
 ing to their temperature. 
 
 Ta^le of Specific Gravities. 
 
 Iron (cast) 7.^ 
 
 " (wrought) 7. 
 
 Steel (soft) 7. 
 
 " (tempered) 7. 
 
 Lead (cast) 11. 
 
 " (sheet) 11.^ 
 
 Brass (cast) 8. 
 
 " (wire drawn). . . 8. 
 
 Copper (sheet) 8. 
 
 " (cast) 8.( 
 
 Gold (cast) 19. 
 
 " (hammered). ... .19. 
 
 " (22 carats) 1^ 
 
 " (20 " ) 15. 
 
 Silver (pure, cast). . . 10.^ 
 
 ' * (hammered) .... 10. 
 Mercury (60°). ...... .13. 
 
 Tin 7. 
 
 Zinc (cast) 7. 
 
 Bronze (gun metal) . 
 Coal (Bitummous) . . . . 1. 
 1. 
 1. 
 
 (Anthracite) 
 
 207 
 
 Charcoal. 
 
 . . . .441 
 
 G88 
 
 Brick 
 
 ... 1.900 
 
 780 
 
 Clay 
 
 ... 1.930 
 
 840 
 
 Common Soil. . . . 
 
 ... 1.984 
 
 400 
 
 Emery 
 
 ... 4.000 
 
 407 
 
 Glass 
 
 ... 3.248 
 
 384 
 
 Grindstone 
 
 ... 2.143 
 
 544 
 
 Gypsum . 
 
 .... 2.168 
 
 767 
 
 Lime 
 
 ... 2.720 
 
 007 
 
 Granite 
 
 . ... 2.625 
 
 238 
 
 Marble 
 
 ... 2.708 
 
 361 
 
 Mica 
 
 .... 2.800 
 
 481 
 
 Millstone 
 
 . ... 2.484 
 
 709 
 
 Nitre 
 
 . ... 1.900 
 
 474 
 
 Porcelain ........ 
 
 . ... 2.385 
 
 511 
 
 Phosphorus ...... 
 
 1.770 
 
 580 
 
 Pumice Stone .... 
 
 915 
 
 .293 
 
 Salt 
 
 ... 2.130 
 
 .215 
 
 Sand 
 
 .... 1.800 
 
 .700 
 
 Slate , 
 
 . .. 2.672 
 
 .2,:g 
 
 Sulphur. ......... 
 
 .... 2.083 
 
 .436 
 
 
 
 .640 
 
 
 
1S8 £ifOWE£]liS' EXAMINATIONS. 
 
 HORSE POWER (H. P.) 
 
 The capacity of work of a steam engine, a steam boiler, 
 or of a whole steam plant is reckoned in horse power. The 
 abbreviation of the term is H. P. 
 
 A horse power is 33,000 foot-pounds, or in other words, 
 33,000 pounds lifted 1 foot high in 1 minute, or 550 pounds 
 lifted 1 foot in 1 second of time, hence 
 
 A foot-pound is one pound moved upward one foot. 
 Example, work done by hfting 30 pounds through a height 
 of 50 feet = 1,500 foot-pounds. 
 
 While, by means of the Indicator, the horse power of the 
 steam engine can be determined to a nicety, the horse power 
 of the steam boiler is almost an unknown quantity ; it has 
 been agreed upon, however, to consider the evaporation of 
 30 lbs. of water in 1 hour to be the standard of efficiency.* 
 
 (^ues. What are the three kinds of horse power spoken 
 and written about, which engineers should learn to dis- 
 tinguish ? 
 
 Ans. Nominal, Indicated and Effective. 
 
 * The several tests made on the boilers used in the recent Chicago 
 Exposition tend to prove that there has been no improvement in the 
 maximum efficiency of boilers since 1876. But boilers are now made 
 which carry high pressure as safely as were the pressures of 1876 by 
 the boilers then made. 
 
QtJiESTtONS AND AJ^STTERS. V6Q 
 
 Ques. What is the difference between these ? 
 
 Ans. The nominal (N. H. P.) is only used as a 
 general statement describing the dimensions of a 
 steam engine for convenience of makers and pur- 
 chasers of steam engine. 2d, the indicated (I. H. P.) 
 is the "calculated" work done within the cylinder. 
 3d, the effective (E. H. P.) is the vi^ork an engine 
 can do after deducting the amount required to drive 
 the engine when it is running unloaded. The letters 
 in brackets show the abbreviations of the terms. 
 
 Ques. How is the horse power of the boiler best deter- 
 mined V * 
 
 Ans. The only sure method is by the actual 
 measurement of the water evaporated. 
 
 Ques. In getting this measurement what precautions 
 should be taken '? 
 
 Ans. Even when the amount of water intro- 
 duced and the quantities passed off from the boiler 
 are accurately known, there yet remains a doubt as 
 to how much has been actually evaporated, and how 
 much may have passed off in priming, unless the 
 trial has been conducted with the boiler open to the 
 atmosphere. To have the boiler thus open appears 
 to be the only condition under which accuracy can 
 be insured, unless a suitable apparatus can be pro- 
 vided for accurately measuring the weight and tem- 
 perature of all thi steam and water given off, when 
 the boiler is working above atmospheric pressure. 
 
 * For the rule for calculating tbe horse power of the Steam 
 Engine, see pages 79 and 80. 
 
140 ENGINEERS' EXAMINATIONS. 
 
 Ques. Can any boiler be said to be free from priming ? 
 
 Ans. There are very few boilers which do not 
 prime more or less, and the quantity of water passed 
 off in this way is quite considerable. 
 
 Qnes. In view of these facts, can there be any accurate 
 results obtained in boiler tests ? 
 
 Ans. Unless the amount of water passed over 
 with the steam by priming or foaming, when work- 
 ing under pressure, can be accurately ascertained, 
 the evaporative results are not to be relied upon, 
 however careful in other respects the trial may have 
 been conducted. 
 
 Ques. Is the intensity of boiling itself constant ? 
 
 Ans. It is not, as the heat is ever varying during 
 the intervals between firing, and the difference in 
 height is thus dependant and changeable. 
 
 (^ues. What is the ordinary shop rule for estimating the 
 horse power of the horizontal tubular boiler V 
 
 Ans. It is customary to consider fifteen square 
 feet when exposed to the heat as being a horse 
 power, and it is figured by the following : 
 
 Rule for Estimating the Horse Power of Horizon- 
 tal Tubular Steam Boilers. 
 
 Find the square feet of heating surface of the shell, heads 
 and tubes, and divide by 15 : the answer is the nominal horse 
 power. 
 
ICE MAKING AND REFRIGERATION. 141 
 
 ICE MAKING AND REFRIGERATION. 
 
 The connection between steam engineering and refrigera- 
 tion is equally intimate as that which exists betw^een engi- 
 neering and electricity. 
 
 Both refrigeration and electricity in their practical appli- 
 cation to the service of mankind demand the highest 
 engineering skill, and it goes without saying that the engineer 
 who is an expert in either of these widening lines of progress 
 will receive comparatively the highest pecuniary return for 
 his service. 
 
 That buildings will be soon cooled and ventilated in an 
 artificial manner is assured by the high efficiency now 
 attained by mechanical refrigerating machines ; some modi- 
 fication of the methods now employed in cold storage houses 
 will be adopted for buildings, and as steam will be the 
 actuating force, engineers must necessarily be employed in 
 the care and operation of the machinery. This makes it 
 desirable that the engineer should become as thoroughly 
 posted as possible, regarding the principles and operation of 
 the various mechanical refrigerating systems now in use, as 
 well as those which will hereafter be developed, and he will 
 find it greatly to his advantage to do so. 
 
 The principles governing artificial refrigeration are simple 
 and are becoming familiar to many engineers, yet many 
 
142 ICE MAKING AND REFRIGERATION. 
 
 engineers understand the practical workings of the machines 
 better than they do the principles upon which they operate — ■ 
 in view of the large future opening to this comparatively 
 new industry it were well to unite the two. 
 
 A few easy definitions at the introduction of the subject 
 may make the path of instruction plainer. 
 
 A refrigerant is anything which abates the sensation of 
 heat, or cools. 
 
 To refrigerate is to cool ; to make cold ; to allay the heat 
 of — 
 
 A refrigerating -machine is a machine for the artificial 
 production of cold. 
 
 Refrigeration is specifically the operation of cooling various 
 substances by artificial processes, and 
 
 Chemical refrigeration is effected by the use of freezing 
 mixtures, which have the property of producing a sufficient 
 degree of cold to freeze liquids. 
 
 Mechanical Refrigeration, in its strictest sense, is the con- 
 version of heat into work by the expansion of a volume of 
 gas or vapor, which performs work during the act of expan- 
 sion ; in a broader sense, it is a process of refrigeration in 
 which the cycle of heat changes is only partly ..produced by 
 mechanical action, the mechanical part of the process being 
 wholly confined to compressing tlie gas or vapor while 
 liquifying it under the action of cold and pressure. 
 
 Every refrigerating apparatus consists of three parts, viz. : 
 1. The power (an engine), and gas (ammonia) pumps which 
 compress the gas to a liquifying pressure. 
 
QUESTIONS AND ANSWERS. 143 
 
 2. A condenser in which the gas is cooled and changed to 
 a liquid. 
 
 3. A system of evaporating coils, in which the liquid 
 ammonia is expanded into a gaseous state and thus cools the 
 surrounding si^ace by the absorption of heat. 
 
 The refrigerating agent better than any known substance 
 which has proved most advantageous is ammonia. This 
 chemical boils at 40° below zero — as water boils at 212° above 
 zero — thus assuring a low temperature without resorting to 
 very low pressures. 
 
 Questions and Answers Relating to Refrig- 
 eration. 
 
 Ques. What is anhydrous ammonia ? 
 
 Ans. The word anhydrous means "free from 
 water ": ammonia unmixed with water is sometimes 
 called dry ammonia. 
 
 Qiies. What are the advantages of ammonia over other 
 fluids for refrigeration ? 
 
 Ans. Its great stability, its non-inflamibility and 
 non-explosiveness ; it does not have the slightest 
 effect on iron and steel, even when mixed with water, 
 so that the machinery and piping which convey and 
 circulate it are never in the least degree corroded, 
 
 Qiies. What is the standard of cold production ? 
 
 Ans. It is the weight of the gas circulated through 
 the system and not the volume of gas. 
 
144 ENGINEERS' EXAMINATIONS. 
 
 Qiies. How much cold can be produced from a pound of 
 coal? 
 
 Ans. Numerous tests have shown that with a 
 fairly constructed refrigerating machine a melting 
 capacity equal to that of 16 to 48 lbs. of ice can be 
 obtained from a lb. of coal.* 
 
 Ques. What is the Brhie system of refrigeration ? 
 
 Ans. In the Brine system one or more tanks of 
 salt water are used, in which the evaporating coils 
 are submerged, and the liquid ammonia, allowed to 
 expand within the coils, assumes its original gaseous 
 condition and in doing so absorbs the heat from the 
 surrounding brine, reducing it to any reouired tem- 
 perature. 
 
 (^ues. In ice making how is the brine tank arranged ? 
 
 Ans. It is arranged to receive galvanized sheet 
 iron cans containing fresh water, which remain in 
 the brine until their contents are frozen into solid 
 blocks of ice. 
 
 Ques. What is the direct expansion system ? 
 
 Ans. In the direct expansion system the ammonia 
 expands directly in coils placed in the rooms to be 
 cooled. 
 
 (Jues. Which system (brine or direct expansion) is mostly 
 used, and why ? 
 
 Ans. The brine system, because the brine tanks 
 afford a considerable reservoir of cold which may be 
 
 * The wide difference given is shown hy the tests and it will b^ 
 found that the capacity varies with the conditions. 
 
QdESTIONS AND ANSWERS. 145 
 
 drawn upon in an emergency; another strong reason 
 is that there is less risk of loss in the cooling rooms 
 from escaped ammonia from leaking pipes ; still 
 another reason for preferring the brine system is 
 because the whole system of the ammonia gas 
 circulation is confined to one room or department 
 and directly under the control of the engineer. 
 
 Ques. In the brine system how is the brine circulated ? 
 Describe the process. 
 
 Ans. It is accomplished by a special pump 
 described as the brine circulating pump, which 
 forces it through the pipes arranged in the rooms to 
 be cooled, from which it returns to the tank to be 
 re-cooled and continually used over again, through 
 an endless round of cooling and warming. 
 
 Ques. Is the brine circulation quite independent of the gas 
 circulation ? 
 
 Ans. Yes, the only spot they come in contact is in 
 the brine tank ; here the cold ammonia gas extracts 
 the heat from the brine as it flows through the tank; 
 the two circulation systems do not come in nearer 
 contact than that. 
 
 Ques. How is the cooling effected in the direct expansion 
 
 system ? 
 
 Ans. In the direct expansion system the ammonia 
 expands directly in coils placed in the rooms to be 
 cooled, the pipes being stronger but in other respects 
 similar to those used in the brine circulation ; in 
 this system the brine pump is omitted. 
 
146 ENGINEERS' EXAMINATIONS. 
 
 Ques. What is the difference between a submerged con- 
 denser and an open air condenser ? 
 
 Ans. In one plan the system of pipes is sunk in 
 a tank containing water and in the other the pipes 
 are exposed to the air and water sprinkled over 
 them. 
 
 Ques. In either plan or method what is the common 
 result ? 
 
 Ans. The water extracts the heat from the pipes, 
 being under the requisite pressure the ammonia is 
 cooled to the temperature of the condensing water, 
 and becoming liquified, is ready for use. 
 
 Ques. What other principal system of refrigeration is in 
 use ? Describe it. 
 
 Ans. The absorption system. This consists in 
 a different arrangement of i, the power, 2, the con- 
 denser, and 3, the evaporating coils, as mentioned 
 on page 142.* 
 
 Ques. What are the parts of the absorption system spec- 
 ially called ? 
 
 Ans. I. The Generator. 2. The Ammonia Pump. 
 3. The Absorber. 4. The Condensing Tank. 5. 
 Weak Liquor Tank. 6, The Equalizer, 7. The 
 Freezing Tank. 8. The Cooling Tank. 9. Receiver 
 for Ammonia. 
 
 * These are mentioned on page 142 as essential to all systeroa pt 
 refrigeration. 
 
QUESTIONS AND ANSWERS. 147 
 
 Ones. What refrigerant is mostly usetl in the absorption 
 system ? 
 
 Ans. Ammonia largely reduced and mixed with 
 water so that it is 26 per cent, strong — called prop- 
 erly, aqua-ammonia. 
 
 (jues. Upon what chemical law is the absorption system 
 based ? 
 
 Ans. Upon that which allows ammonia to boil 
 into gas at 40 degrees below zero, while water is 
 unaffected until 2 1 2 degrees is reached ; the ammonia 
 and water are thereby capable of being separated 
 and thus made to perform continuous work. 
 
 Qiies. What is the expansion valv«e ? 
 
 Ans. It is that which controls the supply of 
 ammonia to the evaporating coils. 
 
 Qiies. What advantage is to be gained by the use of the 
 device called "the agitator " ? 
 
 Ans. Its use is to secure uniform freezing, which 
 is accomplished by continually circulating and agi- 
 tating the bath — this is sometimes done by the use 
 of a centrifugal pump, which draws the brine from 
 one end at the bottom and discharging in the other 
 end at the top. 
 
 (|ues. What is the cycle or circle of the ammonia in its 
 two forms through its round of use and re-use ? 
 
 Ans. I. Compression. 2. Condensation. 3 Ex- 
 pansion. In qrder to render the operation continu- 
 
148 ENGINEERS' EXAMINATIONS. 
 
 ous these three are connected together, the gas 
 passing through the system in the order named. 
 
 Ques. To what extent is the ammonia compressed ? 
 
 Ans. From 125 to 175 lbs. per square inch, 
 depending upon the temperature of the condensing 
 water used, either mechanically or otherwise, in 
 order to prepare it for the second operation-express- 
 ed more plainly, "heat is squeezed out of the gas. 
 
 Qiies. How about the condensation ? 
 
 Ans. The heat developed or "squeezed out "in 
 the compression is withdrawn from the compressed 
 gas by forcing it through coils of pipe while they are 
 in contact with cold water — the heat being trans- 
 ferred to the water surrounding the coils.* 
 
 Ques. Of what does the expansion side consist and what 
 is its operation ? 
 
 Ans. The expansion side generally consists of 
 coils of pipe, in which the gas re-expands and per- 
 forms the refrigerating work ; through these pipes 
 the ammonia gas is drawn by the pumps at a press- 
 ure varying from 10 to 30 lbs. above that of the 
 atmosphere. 
 
 Ques. Where do the " parts " meet ? 
 
 Ans. The liquified gas is allowed to flow to a 
 stop-cock having a minute opening which separates 
 the compression from the expansion sides. 
 
 * When this point is reached the gas is ready to assume the liquid 
 condition, and in so doing, is ready to give off additiooal heat totUfi 
 ewrouading water. 
 
QUESl'TONS AND AN$Wi]RS. 149 
 
 Ques. What are air machines ? 
 
 Ans. Machines that use air instead of ammonia; 
 cold can be generated by the expansion of air ; air 
 becomes heated under compression and will cool 
 down again during compression. Air machines are 
 generally used on ship-board where machines of 
 comparatively small capacities are needed. 
 
 Ques. What are the objections to air machines ? 
 
 Ans. Their large coal consumption, which is 
 eight to ten times that of good ammonia-compress- 
 ion machines— besides this the compressing-pumps 
 are very large, the friction to operate them is great 
 and the loss by leakage around the piston becomes 
 considerable in course of time. 
 
 Ques. What is a double-acting compressor ? 
 Ans. One which handles the gas on Doth the 
 upward and downward stroke. 
 
 Ques. What are its advantages ? 
 
 Ans. The friction will be the same for all the 
 working parts, while double the work is being 
 effected. 
 
 Ques. What is the greatest trouble to be overcome in 
 
 refrigerating machinery 'i 
 
 Ans. Leakage. 
 
 Ques. What should be one of the first rules as to the 
 machinery and appliances ? 
 
 Ans. They should be kept clean and in good 
 order ; means should be provided for cleaning the 
 entire distilling system by steam. 
 
160 iiiSAt A^D WoM^ 
 
 HEAT AND WORK. 
 
 Without heat there would be no steam engine nor steair 
 boiler, neither engineer or fireman. 
 
 The services of the engineer are chiefly devoted to chang- 
 ing heat into work ; the heat which is carried to the engine 
 in the steam is either transformed into useful work, or it 
 passes away to waste in various ways, and the sum of the 
 heat usefully employed plus the heat which is wasted always 
 equals exactly the heat which was applied. ' 
 
 This is owing to a fundamental principle in nature that, 
 just as matter can neither be created nor destroyed, though 
 it may be made to assume different forms, visible or invisible, 
 so energy, whether heat energy or any other, cannot be 
 destroyed. It may take a variety of different forms, but the 
 sum total of the energy remains the same. This principle is 
 called the principle of the ' ' conservation of energy. " 
 
 The temperature of a body indicates how hot or how cold 
 the body is. 
 
 We must not fail, however, to distinguish the temperature 
 of a body from the quantity of lieat in a body. Thus, if a 
 cup of water be dipped out of a pailful of water, the temper- 
 ature of the water is the same throughout, but the quantity of 
 heat varies as the weight of water in each vesseL 
 
BEAT AND WORK. 151 
 
 Before quantities of heat can be measured we must have a 
 unit of heat, just as we require a unit of length. Namely ; 
 the inch or foot in order to measure distance, or the pound 
 or ton in order to measure weight. 
 
 The unit of heat is the amount of heat necessary to raise 
 the temperature of one pound of water one degree Fahren- 
 heit when at a normal temperature. 
 
 Heat is transferable from one body to another, that is, one 
 body can heat another by becoming less hot itself ; thus, the 
 furnace heat is transferred to the boiler plates, thence to the 
 water and steam, and finally to the piston, in the driving of 
 which heat is changed into work. 
 
 The natural condition of heat is a condition of energy, that 
 is of a condition to effect changes — of coal into gas, of water 
 into steam — and steam into work. 
 
 Ques. What is the mechanical equivalent of heat ? 
 
 Ans. The amount of heat necessary to raise i 
 lb, water from or near its freezing point (32°) one 
 degree, is equivalent to the mechanical power which 
 will raise 772 lbs. through a height of one foot. 
 
 Ques. How can we express units of heat as units of work? 
 Ans. Multiply the units of heat by 772. 
 
 Ques. How does this question of heat and work affect the 
 engineer ? 
 
 Ans. The whole business of the engineer is the 
 superintendence of machines by means of which the 
 conversion of heat may be carried out. 
 
152 HEAT AND WORK. 
 
 Ques. What is a thermometer fcH* and how does it act ? 
 
 Ans. Thermometers are used to indicate tern* 
 perature, and they do so by the rise and fall of a 
 little column of mercury enclosed in a tube of very 
 fine bore, and having a small bulb at the bottom 
 containing a store of mercury. 
 
 Qlies. How does this show change of heat or temperature? 
 
 Ans. If the thermometer be warmed by any 
 means, the mercury expands and tends to occupy a 
 larger volume, and the column therefore rises in the 
 stem of the tube ; or, if the thermometer be cooled, 
 the mercury will contract or diminish in volume, 
 and the column will shorten or fall. A graduated 
 numbered scale is affixed and the smallest change in 
 temperature shown by the movement of the surface 
 of the column is thus very easily detected. 
 
 Ques. How is the thermometer scale divided or grad- 
 uated 1 
 
 Ans. The instrument is placed in melting ice, 
 and the point to which the mercury falls is marked 
 the freezing point. It is then put in boiling water 
 exposed to the air and the point to which the mer- 
 cury column rises is marked the boiling point. The 
 distance between these two points on the most com- 
 monly used thermometer, the Fahrenheit, is divided 
 into 1 80 equal parts or degrees. 
 
 On the Centigrade thermometer the distance be- 
 tween these two marks is divided into 100 equal 
 spaces or degrees — the word Centigrade is derived 
 
HEAT AifD WORK.. 
 
 15B 
 
 from the two words meaning a grading by the hun- 
 dred. 
 
 In the Reaumur scale, the same distance is divided 
 into So degrees. 
 
 Qiies. What is the position of zero on these scales ? 
 
 Ans. The last two make the freezing point zero, 
 while the Fahrenheit makes the freezing point 32° 
 and thus the zero is i8o°-|-32°, or 212° below boiling 
 point, and temperatures are measured from zero up 
 and down the scale. 
 
 (^iies. Wliat is meant by the term "energy " ? 
 
 Ans. It may be defined as the power of doing 
 work. When heat is applied to water it confers 
 upon the steam which is produced the power of 
 doing work, such as driving the piston from one end 
 of the cylinder to the other, against a resistance. 
 
 Ques. What is specific heat ? 
 
 Ans. It is the heat required to raise the temper- 
 ature of a substance one degree, as compared with 
 the heat necessary to raise the temperature of an 
 equal weight of water one degree. 
 
 The specific heat of bodies varies very considerably, as will be seen 
 from the following table : 
 
 Table of Specific Heat. 
 Water 
 
 Cast Iron . 
 
 
 
 = i.UUU 
 
 =0.130 
 
 Steel 
 
 
 
 . =0.118 
 
 Wrought Iron 
 
 
 
 =0.113 
 
 Copper 
 
 
 
 =0.100 
 
 Bismuth . 
 
 , 
 
 
 =0.031 
 
 Lead 
 
 , 
 
 
 =0.031 
 
 Mercury . 
 
 » • 
 
 
 =0.033 
 
 Coal 
 
 » 
 
 
 =0.241 
 
154 Mt}AStJttt:S ANi) WMOffM. 
 
 MEASURES AND WEIGHTS. 
 
 A large proportion of time is taken up in counting, in 
 measuring and in weighing, and an engineer's success in the 
 path of advancement is largely influenced by his readiness in 
 these. 
 
 To avoid disputes there needs to be a certain well agreed 
 upon standard, both of weights and measures, by which 
 all will agree to be governed. 
 
 This agreed standard for each operation is called the unit. 
 
 (Jues. What is the unit or measure of time ? 
 
 Ans. A minute. 
 
 (Jues. What is the unit of arithmetical calculations ? 
 
 Ans. The figure (i) one. 
 Ques. What is the unit of pressure ? 
 
 Ans. The pressure of the atmosphere at the level 
 of the sea. 147% lbs. to the square inch. 
 
 Ques. What is the unit of work ? 
 
 Ans. The foot-pound, which is the force required 
 to lift one pound one foot high. 33,000 of these 
 make one horse-power when executed in the unit of 
 time (one minute). 
 
 Ques. What is the unit of heat ? 
 
 Ans. It is the heat required to raise one pound 
 of water one degree — or say, one pound of water 
 from 32° to 33°. 
 
STEAM HEATING AND VENTILATION. 155 
 
 STEAM HEATING AND VENTILATION. 
 
 No small proportion of engineers' positions are retained, 
 after being secured, by a practical familiarity with the care 
 and management of the heating and ventilating apparatus , 
 it is true that nearly always this apparatus is furnished, as 
 to plan and detail, by the architect, yet the engineer must 
 operate it to the satisfaction of the owner of the steam plant, 
 or lose his situation 
 
 Hence it follow? thnt no engineer v/ill be granted a license 
 to run a steam plant, wnere there is an extensive system o£ 
 heating, unless he shows by his answers that he is capable of 
 its management and ujiderstands, somewhat, the principles 
 upon which it acts, 
 
 A system of heating and ventilation should, in the first 
 place be simple, so that the average engineer shall be compe- 
 tent to operate it. It should be of sufficient capacity to do 
 the heating required for all the space, and it should be safe, 
 durable and economical. 
 
 In planning and in the management of the apparatus, both 
 t'ae heating and. ventilation should be considered as one — they 
 are inseparable and together form a complete whole; the 
 apparatus shonlcl warm the air in an enclosed space to a 
 temperature conducive to comfort and health, and supply a 
 fidlunie of oAr sufficient to maintain a sanitary standard of 
 pvrifif; both coaditions — heatina: and ventilation — must b*; 
 
156 ENGINEERS'' EXAMINATIONS. 
 
 controllable and constant, with the air deliveries so made tliat 
 no complaint can be found with the engineer-in-cliarge. 
 
 In heating and ventilating the natural laws which govern 
 must be regarded, otherwise all applications will be experi- 
 mental, thus: 
 
 1. Air occupies space the same as solids and liquids, but 
 because it is invisible it is not so regarded. 
 
 2. Cold air falls because of its density and heated air 
 rises because of its rarity. 
 
 3. A given volume of air occupies a given space ; a like 
 volume cannot occupy the same space at the same time. 
 
 4. A volume of air can be delivered into a room only 
 equal to the quantity displaced therefrom ; when a space is 
 full it can hold no more. 
 
 Ventilation is a substitution of fresh air for foul ; it should 
 be a gradual, constant and complete changing of the air in a 
 room or structure. 
 
 The piping of a mill or factory or workshop was, compara- 
 tively, a few years ago, an easy task. To-day high buildings, 
 v/ith hundreds of business offices, government buildings with 
 elaborate equipment and furniture, art institutes and 
 museums with treasures and relics, mansions and cottages, 
 are being warmed by special systems studied out by the 
 mechanical engineer and master steam-fitter. 
 
 The systems are becoming intricate ; they require drawings, 
 planning, accurate measurements and calculations on areas 
 and capacities, mechanical knowledge of steam and water, of 
 pipes, furnaces, boilers, valves, fittings and those other 
 adjuncts which have become necessary in the extensive iise 
 
QUESTIONS AND ANSWERS. 15"? 
 
 of steam and hot water. In short, there is a great deal to be 
 learned concerning present methods, and a great deal more 
 to be learned la the future, as experience, invention and 
 improvement will show. 
 
 It is, therefore, time for this branch of business — steam 
 and hot water heating — to be recognized as one worthy of 
 attention, investigation and study. 
 
 Questions and Answers Relating to Heating 
 and Ventilation, 
 
 (Jues. What is a very important princii)le to be observed 
 in arranging a system of piping ? 
 
 Ans. They should be so designed that there is a 
 gradual slant from feed to return, with no air or 
 water " pockets " and nothing to be in the way of a 
 thorough circulation. 
 
 (Jues. How should the fire surface of a boiler be propor- 
 tioned to the quantity of pipe to be heated ? 
 
 Ans. The extent of surface which a boiler should 
 expose to the fire should be proportional to the 
 quantity of pipe to be heated, and a small apparatus 
 should have more surface of boiler in proportion to 
 length of pipe than a larger one, as the fire is less 
 intense and burns to less advantage in a small fur- 
 nace than in a large one. It is more economical to 
 
158 ENGINEERS' EXAMINATIONS. 
 
 work with larger surface of boiler at moderate heat 
 than to keep the boiler at its maximum temperature. 
 
 i 
 
 Ques. In taking charge of a new plant, what is the first 
 thing to be done by the engineer ? S 
 
 Ans. To ascertain the exact course, size and 
 operation of the steam, water, drain and other pipes. 
 
 Ques. Why is it necessary to do this so soon ? 
 
 Ans, Because the boilers cannot be supplied 
 with water even, nor blown off without the pipes 
 being in order, nor steam taken to the engine nor 
 distributed in a heating system without proper con- 
 nections. Besides, it is well to do the most difficult 
 thing first — the piping, being largely out of sight, is 
 most difficult to inspect — more so than the engine, 
 boilers or pumps. 
 
 Ques. Name some of the essentials to an efficient system 
 of piping ? 
 
 Ans. Pipes and valves should be of sufficient size 
 to carry the full pressure of the boiler to the engine; 
 elbows with a long turn are best, and T's are to be 
 avoided, if possible. Pipes of proper size and easy 
 bends are essential to economy. 
 
 (^ues. What other matter relating to the piping is essential 
 to economy ? 
 
 Ans. The covering of all pipes by some good 
 non-conducting substance, as condensation in the 
 pipes when uncovered or partly covered increases 
 greatly the cylinder condensation. This covering i,s 
 
QUESTIONS AND ANSWERS. 159 
 
 as important in warm as in cold weather, as steam 
 So to loo lbs. pressure has a temperature of 325 to 
 342 degrees of heat. 
 
 Ques. What is well to be known by an engineer relating 
 to steam fitting and piping ? 
 
 Ans. It is almost a necessity to know the names 
 and uses of pipe fitter's tools, to be familiar with the 
 different fittings and styles of valves, sizes, ete. 
 
 (Jues. What are some of the fittings ? Name a few of 
 them. 
 
 Ans. Gaskets, nipples, steam and water unions, 
 couplings, ells, lock nuts, off-setts, coils, radiators, 
 steam traps, headers. 
 
 Ques. What is the very best non-conductor of heat ? 
 
 Ans. Confined air — hence the best composition 
 for steam pipes is that which has the largest quan- 
 tity of confined air mixed with the material of which 
 it is composed. 
 
 Ques. In pipe covering what two dangers must be guarded 
 against ? 
 
 AilS. The danger of fire, and second, that there 
 are no currents of air formed between the pipe and 
 the covering. 
 
 (^ues. What is the latest idea in regard to ventilation ? 
 
 Ans. That the best results are only to be had by 
 a mechanical system, extracting the air and replac- 
 ing it by fresh supplies — hence the increasing use of 
 exhaust fans and blowers driven by various motors. 
 
160 THE SMOKE PROBLEM. 
 
 THE SMOKE PROBLEM. 
 
 Much vexatiovis litigation has been caused by the " smoke 
 nuisance ", so denominated in the ordinances passed by rafoiy 
 cities ; there has been a hvely controversy between the offi- 
 cials and steam-visers as to, first, the possibility and, second, 
 the practicability of preventing smoke from issuing from the 
 tops of the chimneys of steam plants. Many proprietors 
 have been called to the bar of justice and fined for the 
 offence, and not a few engineers have been threatened with 
 arrest ; at times both engineers and owners have been sum- 
 moned to plead guilty or not guilty to the crime of smoke 
 production. 
 
 That smoke can be absolutely prevented is proved by the 
 operations of gas works, which yearly converts mto gas, 
 coke, tar, etc., millions of tons of bituminous coal without 
 smoke. 
 
 The smokeless combustion of powdered coal, which has 
 recently become an important fact in Europe, is greatly 
 facilitated by the adoption of a new automatic mechanism 
 and other arrangements. The fuel, instead of being intro- 
 duced in the ordinary manner, is first ground to a powder, 
 and, in place of the ordinary boiler fire-box, there is a com- 
 bustion chamber in the form of a closed furnace lined with 
 firebrick, and having an injector similar in construction to 
 those used in oil burning furnaces. This chamber has two 
 openings, one on the centre line and in the place of the usual 
 
THE SMOKE PROBLEM. 161 
 
 furnace fire dooi* and the other on the opposite side The 
 orifice of the nozzle is placed in the latter aperture and 
 throws a constant stream of fuel into the chamber, the 
 nozzle being so located that it scatters the powder throughout 
 the whole space of the firebox ; when the powder is once 
 ignited, which is very readily done by first raising the lining 
 to a high temperature by an open fire, the combustion con- 
 tinues in an intense and regular manner under the action of 
 the current of air which carries it in. This current is regu- 
 lated by the amount of powder required for the production of 
 the heat led off to the boiler and the evaporation of the 
 weight of steam demanded. 
 
 It may thus be seen that the question is not one of possi- 
 bility but of practicability or economy ; it being allowed that 
 smoke prevention cannot be economically effected, then the 
 
 English, towns are more troubled by the smoke nuisance than any 
 of those of our own country. The absolute abatement of the smoke 
 being economically impossible, the cities have adopted ordinances to 
 control and minainiize the nuisance. Thus Manchester, for example, 
 has a city law which permits of the continuous emission of black 
 smoke from any factory for one minute each half hour. Oldham 
 allows nine minutes per hour. St. Helens, Newcastle-on-Tyne and 
 Leeds, five minutes. At Birmingham the inspectors watch the chim- 
 ney for an hour ; they report the way in which the smoke is emitted, 
 whether continuous or at intervals. For a first offense, or where a 
 long time has elapsed between offenses, letters of caution are sent out. 
 Shetfleld allows six minutes in the hour, but where there are not more 
 than three steam boilers and no furnaces, four minutes in the hour 
 only. At Stoke-on-Trent if black smoke is emitted for a longer period 
 than fifteen minutes, proceedings are taken. Bolton allows two and a 
 half minutes in the half hour. In this connection it may be of inter- 
 est to state that the Manchester Association has caused 1827 half- 
 hourly observations to be made of various chimneys of the members, 
 and the result of these observations showed that black smoke issued 
 for 3224 minutes, an average cf one minute forty-six seconds per half 
 hour. 
 
163 THE SMOKE PROBLEM. 
 
 problem is as to a medium effect. Attention is called to the 
 foot note regarding the practice obtained in England in 
 dealing with the question. 
 
 "Human nature has not," said recently a distinguishe** 
 lecturer, "is not, nor will it ever, be able to dole out the 
 exact equivalent of air necessary for the complete consump- 
 tion of each fresh charge of coals on the furnace grate." 
 One of the reasons given was, ' ' that coals differed so much 
 in the quantity of their constituents as to make the above 
 impossible. " 
 
 In an investigation made by the lecturer, data was collec- 
 ted of the number of tons of coal consumed in a given time 
 by thirteen puddling furnaces, and also of the color of the 
 smoke em'".ted from the same. About 30,000 cubic feet of 
 smoke gases were emitted every seventy seconds, of which 
 the speaker declared that, "he was willing to forfeit any 
 reasonable sum of money, if any one could prove that there 
 was more than one part by weight of unburnt fuel in 2,680 
 parts, owing to rarefaction and the smoke on the average 
 being only of a ligMt brown color. " 
 
 One point niade is not without its pertinence in the present 
 crusade against the smoke nuisance, and it is given as stated 
 regarding some unreasonable prosecutions made of offenders : 
 " If people more generally knew what the composition of 
 smoke was, manufacturers would not in many cases be per- 
 secuted and prosecuted as at present, and authorities would 
 exercise their discretionary powers in a more sensible and 
 lenient manner. " It need hardly be said that in very many 
 instances of offense this criticism is not without its weight. 
 
QUESTIONS AND ANSWERS. 163 
 
 Questions and Answers Relating to the 
 Prevention of Smoke. 
 
 Qnes. 'V\1iat is the first requisite in the solution of the 
 smoke problem ? 
 
 Ans. Its formation should be prevented at the 
 start, as the after-combustion or burning of smoke is 
 almost impossible and quite the reverse of econom- 
 ical. 
 
 Ques. Give the generally accepted practice in prevention 
 of smoke. 
 
 Ans. A high furnace temperature is most essen- 
 tial and this is best secured by a good draft; second, 
 ample space in the furnace or combustion chamber 
 for the mixture of the products of combustion 
 (gases), mixed with, third, a due proportion of air ; 
 this must be supplied in some common sense manner, 
 either through perforations in the furnace door or 
 through minute openings in the bridge or side walls. 
 
 ^ues. Where must the air be otherwise supplied ? 
 Ans. Through the grate bars. 
 
 Ques. What proportion of air space should there be 
 between the bars ? 
 
 Ans. Generally speaking, 50 per cent., although 
 this amount may be increased for large size, hard 
 and lump, bituminous coal ; for pea or nut coal the 
 distance between the bars must be less. 
 
164 ENGIlsrEERS' EXAMINATIONS. 
 
 Ques. What are some of the principal difficulties in the 
 way of smoke prevention ? 
 
 Ans. The worst trouble comes from uneven 
 chimney draft, and again the varying qualities of 
 coal which require different quantities of air-admix- 
 ture. 
 
 Qnes. Is there any difference made in the quantity of 
 smoke by having too much or too little air ? 
 
 Ans. Yes, either too much or too little air causes 
 imperfect combustion — hence the smoke. 
 
 Ques. If the exact quantity of air needed was supplied to 
 the furnace, would there be any smoke ? 
 
 Ans. Not any to be observed. It may be said 
 thus — with no air absolutely no combustion ; with 
 right quantity — then perfect combustion ; with too 
 much or too little then — smoke. 
 
 Computations usually made of stack capacity assume the chim- 
 ney gases to be of the same specific gravity as air. This is not true, 
 as when combustion is complete the gases are really a mixture of 
 carbonic acid gas, nitrogen and steam ; the proportions varying with 
 different coals. As these require different amounts of air, the vary- 
 ing weights of the gases of combusiion cause a difference in the draft 
 power of the same chimney. It is rare that just the proper amount of 
 air is admitted, and there is a loss when the amount is too little or too 
 great. YevY often there is a surplus of air. reaching sometimes as 
 high as 100 per cent. 
 
ARITHMETICAL SIGNS. 165 
 
 ARITHMETICAL SIGNS. 
 
 There are various characters or marks used in arithmetical 
 computations, to denote several of the operations and propo- 
 sitions, the chief of which are as follows : 
 
 = Equal to. The sign of equality ; as 100 cents=$l, signi- 
 fies that 100 cents are equal to one dollar. 
 
 — Minus, or Less. The sign of subtraction ; as 8— 2=6 ; 
 that is, 8, less 2, is equal to 6. 
 
 -{- Plus, or More. The sign of addition ; as 44-5=9 ; that is, 
 4, added to 5, is equal to 9. 
 
 X Multiplied by. The sign of multiplication ; as 6x6=36 ; 
 that is, 6, multiphed by 6, is equal to 36. 
 
 ~ Divided by. The sign of division ; as 12 -=-3=4 ; that is, 
 
 12, divided by 3, is equal to 4. 
 
 : is to ) 
 
 . ( The signs of proportion ;as2:4::8:16; that is, 
 : : so IS > ° jr- r- ' > 
 
 , i as 2 is to 4, so is 8 to 16. 
 
 7 — 2-j-5=10. Shows that the difference between 7 and 2, 
 added to 5, is equal to 10. 
 
 ^ added to a number, signifies that the number is to be 
 squared ; thus : 6-, means that 6 is to be multiplied by 6. 
 
 ^ added to a number, signifies that the number is to be 
 cubed; thus : 53 = 5x5x5=125. The index, or poiver, 
 is the number of times a number is to be multiplied by 
 itself, and is shown by a small figure placed at the right 
 of the number to be raised, and a little elevated. 
 The bar signifies that all the numbers under it are to be 
 taken together ; as 7+4-3=8 ; or, 5x6+4=50. The 
 parenthesis ( ) is sometimes used in place of the bai*. 
 
166 SVMMAnr OF ABtTHMETtC. 
 
 SUMMARY OF ARITHMETIC. 
 
 The following abridgment of several of the rules of arith- 
 metic, often referred to in elementary books on mechanical 
 science, are here inserted for the convenience of reference. 
 These rules and examples are given merely to refresh the 
 memory, it being taken for granted that the reader has 
 already acquainted himself w^ith the principles of common 
 arithmetic. They vs^ill, ho we er, be found serviceable, both 
 as a convenience of reference, and to give some insight to the 
 subjects on which they treat. 
 
 DECIMAL FRACTIONS. 
 A decimal fraction derives its name from the Latin decern, 
 "ten," which denotes the nature of its numbers, representing 
 the parts of an integral quantity, divided into a tenfold pro- 
 portion. It has for its denominator a unit, or whole thing, 
 as a gallon, a pound, a yard, &c., and is supposed to be 
 divided into ten equal parts, called tenths ; those tenths into 
 ten equal parts, called hundredths, and so on, without end. 
 
 The denominator of a decimal being always known to con- 
 sist of a unit, with as many ciphers annexed as the numera- 
 tor has places, is never expressed, being understood to be 10, 
 100, 1000, &c., according as the numerator consists of 1, 2, 3, 
 or more figures. Thus : -f^ -f^^ iWo <^c., the numerators 
 only are written with a dot or comma before them, thus -2 
 24 -125. 
 
SUMMARY OF ARITHMETIC. 167 
 
 The use of the dot (*) is to separate the decimal from the 
 whole numbers. 
 
 The first figure on the right of the decimal point is in the 
 
 place of tenths, the second in the place of hundredths, the 
 
 third in the place of thousandths, &c., always decreasing 
 
 from the left towards the right in a tenfold ratio, as in the 
 
 following 
 
 Table. 
 
 § "^ S "S .•'So 
 
 ■■■ "^ ^ M S g ^ 
 
 o 
 
 
 
 
 
 ^ 
 
 0) 
 
 
 
 
 H 
 
 
 
 
 
 p 
 
 
 
 
 o 
 
 ^ 
 
 
 
 
 ^ 
 
 H 
 
 n3 
 
 a 
 
 ^. 
 
 
 
 O 
 
 a> 
 
 
 
 
 
 
 
 w 
 
 
 O 
 
 
 -s s s ^ ^. -^ 
 
 r, I'mwj <»'^l3 a^i5i' I'li'^ o^w^IJ 1* S 
 
 Ascending. Descending 
 
 A cipher placed on the left hand of a decimal decreases its 
 value in a tenfold ratio by removing it farther from the 
 decimal point. But annexing a cipher to any decimal does 
 not alter its value at all. Thus 0-4 is ten times the value of 
 0-04, and a hundred times 0-004. But 0-7=0-70=0-700= 
 0*7000, &c., as above remarked. 
 
 0*2 is read two-tenths. 
 
 0-25 " " twenty-five hundredths. 
 
 0"375 " " three hundred and seventy-five thousandths. 
 
 0'1876 " " one thousand eight hundred and seventy -six 
 ten thousandths, and so on. 
 
 Mixed numbers consist of a whole number and a decimal ; 
 as 4-25 and 3-875. 
 
168 
 
 8t7MMABr OF ARITHMETIC. 
 
 Addition of Decimals. 
 
 Rule. — Arrange the numbers so that the decimal points 
 shall be directly OA'er each other, and then add as in whole 
 numbers, and place the decimal point directly below all the 
 
 other points. 
 
 FRACTIONS. 
 
 ^^ is the same as 
 
 ,30.. 
 
 
 7 
 84 
 
 5 
 480 
 685 
 
 5 
 
 07 
 030 
 
 1248 
 
 read 
 read 
 read 
 read 
 
 6 read 
 
 000008 read 
 25 read 
 
 0000006 read 
 read 
 5748086 read 
 
 5 Tenths. 
 
 7 Hundredths. 
 30 Thousandths. 
 
 1248 Ten Thousandths. 
 
 8 and 6 Tenths. 
 
 7 and 8 MiUionths. 
 84 and 25 Hundredths, 
 5 and 6 Ten MiUionths. 
 480. 
 
 585 and 5748086 Ten 
 MiUionths. 
 
 Subtraction of Decimals. 
 
 Rule. — Place the numbers directly under each other, 
 according to their several values, as in addition ; then sub- 
 tract as in whole numbers, and point off the decimals, as in 
 the last rule 
 
 Example. — Subtract 7-75 from 15-135. 
 
 15-125 
 
 7-75 
 
 7 "375 remainder. 
 
summary of arithmetic, 169 
 
 Multiplication of Decimals. 
 
 Rule. — Place the factors under each other, and multiply 
 them together as in whole numbers ; then point off as many 
 figures from the right hand of the product as there are 
 decimal places in both factors, observing, if there be not 
 enough, to annex as many ciphers to the left hand of the 
 product as will supply the deficiency. 
 
 Example.— M.ultii>lj 3-625 by 2-75. 
 
 3 -625x2 -75 =9 -96875. Ans. 
 
 Division of Decimals. 
 
 Rule. — Prepare the decimal as directed for multiplication; 
 divide as in whole numbers ; cut off as many figures for deci- 
 mals in the quotient as the number of decimals in the dividend 
 exceeds the number in the divisor ; and if tlie places in the 
 quotient be not so many as the rule requires, supply the 
 deficiency by annexing ciphers to the left hand of the 
 quotient. 
 
 Eocample 1 —Divide 173-5425 by 3-75. 
 
 3 -75)173 -5425(46 -37 
 1500 
 
 2354 
 
 2250 
 
 1042 
 750 
 
 2925 
 2625 
 
 300 
 
170 SUMMARY OF ARITHMETIC. 
 
 Example 2.— Divide 63-50 by 4-25, 
 
 4-25)63-50(14-94 
 425 
 
 2100 
 1700 
 
 4000 
 3825 
 
 1750 
 1700 
 
 RULE OF THREE, OR PROPORTION. 
 
 The Rule of Three teaches how to find a fourth propor- 
 tional term to three given numbers. 
 
 The rule of three is either direct or inverse. 
 
 When more requires more, or less requires less, it is direct. 
 Thus, if 5 barrels of beef cost $30, what will 12 barrels cost? 
 Or, if 30 cubic inches of cast iron weigh 8 lbs., what will 878 
 cubic inches w^eigh ? 
 
 The proportion in both of the above cases is direct, and the 
 statement must be 
 
 As 5 : 30 : : 12 : 4th term=72 Ans. 
 30 : 8 : : 378 : " =100| lbs. Ans. 
 
 When more requires less, or less requires more, the rule is 
 inverse. Thus, if 3 men do a certain piece of work in 5 days, 
 in how many days will 4 men do the like quantity ? Or, if 
 12 men build a certain quantity of wall in 28 days, in how 
 many :1a ys wUl 8 men perform the same work ? 
 
SUMMARY OF ARITHMETIC. 171 
 
 Here the proportion is inverse, and the statement must be 
 4 : 5 : : 3 : 4th term=3f. Ans. 
 ^' 8 : 28 : : 12 : " =42. Ans. 
 
 The product of the second and tliird terms, divided by the 
 first, always gives the fourth term. 
 
 Three numbers are necessary for a statement ; and two of 
 these must contain the supposition, and the third the demand. 
 
 Eule. — Of the three given numbers, place that for the third 
 term which is of the same kind with the answer sought. 
 
 Then consider, from the nature of the question, whether 
 the answer will be greater or less than this term. If tiie 
 answer is to be greater, place the greater of the two numbers 
 for the second term, and the less number for the first term ; 
 but if it is to be less, place the less of the two remaining num- 
 bers for the second term, and the greater for the first ; and 
 in either case multiply the second and third terms together, 
 and divide the product by the first for the answer, which will 
 always be of the same denomination as the third term. 
 
 Note. — If the first and second terms contain different denomina- 
 tions, tliey must both be reduced to the same denomination ; and 
 compound numbers to integers of the lowest denomination contained 
 la it. 
 
 what will 130 tons 
 
 Example. 
 
 — If 40 tons of iron cost 
 
 cost? 
 
 
 
 TONS. DOLLS. TONS. 
 
 
 40 : 450 : : 180 
 
 
 130 
 
 
 13500 
 
 
 450 
 
 
 4|0)5850|0 
 
 1462-5 dollars. Ans. 
 
172 SUMMARY OF ARITHMETIC. 
 
 ARITHMETICAL PROGRESSION. 
 
 Arithmetical Progression is a series of numbers which 
 succeed each other regulai-ly, increasing or diminishiug by a 
 constant number or common difference : 
 
 As 1, 3, 5, 7, 9, &c. ) increasing series. 
 15, 12, 9, 6, 3, &c. ) decreasing series. 
 
 The numbers which form the series are called terms. The 
 first and the last term are called the extremes, and the others 
 are called the means. 
 
 In arithmetical progi'ession, there are five things to be con- 
 sidered, viz. : 
 
 1, The first term. 
 
 2, The last term. 
 
 3, The common difference. 
 
 4, The number of terms. 
 
 5, The sum of all the ternu* 
 
 These quantities are so related to each other, that ■when 
 any three of them are given, the remaining two can be found 
 
 Given the first tervi, the common difference, and the num 
 her of terms, to find the last term. 
 
 Ride. — Multiply the number of terms, less one, by the 
 common difference, and to the product add the first term. 
 
SUMMABT OF ARITHMETIC. 173 
 
 Example. — What is the 20th term of the arithmetical pro- 
 gression, whose first term is 1, the common difference ^ ? 
 20— 1 = 19 and 19 xi= 9^; and 9i+l=10i. Ans. 
 
 Given the numher of terms and the extremes, to find the 
 common difference. 
 
 Rule. — Divide the difference of the extremes by one less 
 than the number of terms. 
 
 Example. — The extremes are 3 and 29, and the number of 
 terms 14, required the common difference. 
 
 29— 3=26; and 26 -M 3 =2. Ans. 
 
 Given the common difference and the extremes, to find the 
 number of terms. 
 
 Ride. — Divide the difference of the extremes by the com- 
 mon difference, and to the quotient add one. 
 
 Example. — The first term of an arithmetical progression is 
 11, the last term 88, and the common difference 7. What is 
 the number of terms ? 
 
 88—11 = 77; and 77-^7=11 ; 11+1 = 12. Ans. 
 
 Given the extremes and the number of terms, to find the 
 sum of all the terms. . 
 
 Bide. — Multiply half the sum of the extremes by the num- 
 ber of terms. 
 
 Example. — How many times does the hammer of a cljck 
 strike in 12 hours ? 
 
 l-(-12=13 the sum of the extremes. 
 Then 12 X (13 -^2) =78. Ans. 
 
174 RULE FOR SETTING 
 
 TO SET THE VALVES OF A CORLISS 
 ENGINE.* 
 
 And make proper adjustment of valve gear and regulator, 
 please read carefully and follow the instructions here given : 
 
 The Steam and Exhaust Valves. — Take off the back 
 valve chest cover or bonnets and upon the bore of the seats 
 you will find a mark which is in line with, or coincides with 
 the closing edge of the port for that particular valve seat. 
 Look upon the end of the valve and find a mark running 
 towards the centre of the valve ; this line coincides with the 
 closing edge of valve. Note that in case of the exhaust 
 valve, the valve controls the part leading into the exhausi 
 passage and not the opening from the cylinder downward 
 The upper edge of the exhaust port is the closing edge an(? 
 the outer edges of the steam ports are the closing edges. 
 
 The Wrist Plate — should now be looked over and you 
 will find a mark upon the hub of the same, and correspond- 
 ing marks upon the hub of the wrist plate bracket. Also 
 marks which show the full extent of motion of the wi-ist 
 plate when it is moved back and forth by the eccentric. The 
 wrist plate should be located exactly central between the 
 four valves and is so placed in the shop in building the 
 
 * These directions are given by E. P. Hampson to accompany the 
 Eclipse Corliss Engine, and are sufficiently general to answer for any 
 Corliss Engine. 
 
CORLISS ElMGINE VALVES. 175 
 
 machine, and all adjustments are made and valves properly 
 set, but in taking apart for adjustment it may be possible 
 that the adjustments may be distributed and need careful 
 going over before attempting to start the engine for the first 
 time. 
 
 To Test the Marks on Wrist Plate Hub — connect the 
 eccentric rods and engage or drop the carrier rod back upon 
 the wrist plate stud ; then turn the eccentric upon the shaft, 
 the full extent of its throw or vibration each way, and 
 observe if the marks upon the hub of wrist plate at full 
 throw agree with the marks upon the bracket ; if not, dis- 
 connect the strap from eccentric rod, and adjust the screw 
 on stub end by lengthening or shortening, as required, until 
 the marks do agree on both extremes of movement. Now 
 you are ready 
 
 To Set the Valves. — Place the wrist plate in a vertical 
 position (at the central mark) ; turn the valves around in 
 their seats until the steam valves show by the closing edge 
 marks upon their ends by comparison with the port line 
 marks in the seats, that the steam-valve edges lap over or 
 cover the ports I of an inch for 18 inch bore of engine 
 cylinder, f for 24-inch cylinder, and -^^ for 30-inch cylinder. 
 The exhaust valves should show from ^V ^o I '^P' ^^- 
 cording to size of cylinder. 
 
 In Connecting the Wrist Plate — see first that the cut-off 
 latch is hooked on the stud or is engaged. Leave the plate 
 and valves in this position and adjust the length of the wrist 
 plate rods to suit the distances between the studs, or, in other 
 words, connect the wrist plate and steam and exhaust valve 
 
176 RULE FOR SETTING 
 
 arms so the wrist plate stands at the central mark or vertical, 
 and the steam and exhaust valve have the proper lap and 
 opening as instructed, the proper amount of steam lap and 
 exhaust opening being determined by the size of the engine. 
 
 To Make Final Adjustments. — Now you can drop the 
 wrist plate carrier rod hook on the stud, place the engine 
 upon the centre, knowing ■which way the engine shaft is to 
 run, turn the eccentric upon the sliaft, it being loose, in the 
 same direction in which the shaft is to run, a little more 
 than at right angles ahead of the crank or until the steam 
 valve on the same end as the jaiston is just beginning to open, 
 say -^^ of an inch — in this position secure the eccentric on the 
 shaft by means of the set screws in the hub. (See in aU 
 cases that the steam valves are hooked up or engaged by the 
 cut-off mechanism.) Then turn the engine on the opposite 
 centre and see if the steam valve on that end has the same 
 amount of opening ; if not, you can make the adjustment by 
 lengthening or shortening the wrist plate rod attached to 
 this valve. 
 
 To Adjust the Cut-Off, see that the governor and 
 connections are put together properly, and block the gover- 
 nor about half way in the slot ; then fasten the reach or cam 
 rod lever so it stands about at right angles to a line drawn 
 midway between the reach rods ; then lengthen or shorten 
 the reach rods until the cam or trip levers stand vertical or 
 plumb. The governor and connections now occupy the 
 proper relative positions, and it remains to make the 
 
 Exact Adjustment and to equalize the cut-off, so the 
 game amount of steam is admitted at each end of the stroke-. 
 
CORLISS ENGINE VALVES. -(77 
 
 Also, lower the governor and observe when the governor is 
 down that the cut-off mechanism does not unliook but allows 
 steam to be taken full stroke,* after wliich place the engine 
 at, say I of the stroke, which can be done by measuring upon 
 the shde ways from each end and turning the engine (icith 
 all parts connected up) until crosshead is fair with the mark, 
 then slowly raise the governor until the cut-off on the end 
 taking steam trips or unhooks, and to insure this point 
 being accurately determined, it is well to stand by with the 
 hand pressing down upon the dash-j)ot rod ; now block the 
 governor in this position and try the cut-off on the other 
 stroke same distance from the end. After a few trials back 
 and forth and adjusting the length of the cam rods, the 
 cut-off can be made to drop at precisely the same point of 
 stroke. Take care to secure everything permanently v^hen 
 done. 
 
 The Dash-Pot Rod should be adjusted in length so the 
 steam valve arm resting thereon, when the dash-pot plunger 
 is home, or at the bottom of the pot, is in such a position 
 that the latch is sure to hook over the latch stud, and the 
 stud lays midway between the latch die and the closing 
 shoulder. This will insure, on the other hand, the positive 
 engagement of the latch, and on the other hand prevent the 
 she alder from jamming down upon the latch stud in steam 
 arm. If the dash-pot rod is too short the latch will not hook 
 on. Look out for this. 
 
 * Here we would say that it does not appear to be generally known 
 that the Corliss valve motion, when properly made, is provided with 
 a positive closing device which, in case the valve does not trip, posi- 
 'Vely closes the valve before piston reaches the end of the stroJie, 
 
178 CORLISS ENGINE VALVES. 
 
 The Dash-Pot is provided with a leather packing in the 
 vacuum plunger underneath the dash-pot proper. This should 
 be kept in good condition. To spread the packing introduce 
 some liners of paper inside the flange or cup leather. When 
 leather is adjusted just right the pot works promptly and 
 softly. The air valve in the air opening is to regulate the 
 amount of air cushion by turning the screw in the escape 
 hole. 
 
 The Regulator Gag-Pot is used on Corliss engines to 
 prevent over-sensitiveness of the governor, and to its re- 
 sponse to trivial changes. Use only coal or kerosene oil in 
 this pot, and remove one or more of the screws in the piston 
 to give freedom of motion. See that all parts of the gover- 
 nor move freely. 
 
 Using a Steam Engine Indicator to test the correctness 
 of valve setting is the most approved method known, and 
 should be applied in cases where an indicator can be obtained. 
 Recollect that to adjust the point of cut-off to take same 
 amount of steam to each end, adjust the cam or reach rods. 
 To give more or less lead adjust the wrist plate rods. 
 Lengthening them increases the lap, and shortening them 
 gives more lead. The same with the exhaust valves, the 
 cushion or release being affected thereby. If the eccentric 
 is properly set it is not necessary to disturb it in ordinary 
 cases. In closing these directions, let us impress upon you 
 the necessity of marking everything, so at a glance you cau 
 teU if it has been disturbed. 
 
 i 
 
RULES USEFUL TO THE ENGINEER. J 79 
 
 Emergency Rule for Setting Slide Valves. 
 
 If the eccentric slips around the shaft, or any other acci- 
 dent throws the valve-gear out of position, then, 
 
 1. Have some one roll the engine forward in the direction 
 it runs until the crank is on the dead centre. 
 
 2. Open the cylinder cocks at each end. 
 
 3. Admit a small amount of steam into the steam chest by 
 opening the throttle slightly. 
 
 4. Roll the eccentric forward, in the direction the engine 
 runs, until steam escapes from the cylinder cock at the end 
 where the valve should begin to open. 
 
 5. Scre^v your eccentric fast to the shaft. 
 
 6. Roll your crank around to the next centre, and ascertain 
 if steam escapes at the same point, at the opposite end of the 
 cylinder. If so, the valve is in position for service, until an 
 opportunity occurs to open the steam-chest and examine the 
 valve-gear. 
 
 Emergency Rule for Setting Duplex Pump Valves, 
 
 Take off the valve chest cover, push the piston to water 
 end, mark the piston rod by tying a string at the gland, then 
 push same piston to stem end and tie another string around 
 it. Find the center between the two marks and move the 
 piston until the centre mark reaches the gland where the 
 first mark was made. After this is done see how the valve is 
 for lead ; if equal at both ends your valve is set, if not, adjust 
 your jam nuts to suit. Work the same way with the other 
 piston. 
 
180 A PRELIMINARY EXAMINATION. 
 
 A PRELIMINARY EXAMINATION CONDUCTED 
 BY ONE'S SELF- 
 
 1. Can I build and maintain a fire with an in*^ensity of 
 heat sufficient to liold a working pressure of steam ? 3. Can 
 I fire with soft coal and prevent smoke issuing from my 
 chimney in too large volumes ? 3. Can I pack the valve 
 stems, chest covers and piston rods of the engine and feed 
 pump ? 4. Can I line up shafting ? 5. Can I lace up a belt 
 in a suitable manner and run it on the pulley safely ? 6. Do 
 I understand, and can I replace the working points of the 
 feed pump when they become worn ? 7. Can I determine, 
 by its action, whether i)ump is delivering water to the boiler 
 or not ? 8 If not, can I tell where the difficulty exists ? 
 
 A chief engineer's position is no sinecure. It reqtiires 
 constant study, thought and action. It takes men of hard 
 brains to fill soft situations, it also requires years of applica- 
 tion for brains to harden, hence one too young or inexperi- 
 enced should hesitate in accepting a position which they 
 know they cannot possibly fill with mutual profit to them- 
 selves or the owners. 
 
 l^lementary and Preliminary Questions hy the 
 Examining Engineer. 
 
 These questions are given as those frequently asked of the 
 applicant upon his first appearance for examination. 
 
 i. Where and how long did you serve in the works at the 
 making or at the repairing of engines and in what capacities? 
 
A PBELIMINABY EXAMINATION. 181 
 
 2. How long have you served as fireman ? How long have 
 you been employed as an engineer, and where? '6. Give 
 some further idea of the extent of your experience as an 
 engineer. 4. What kind of engines are you familiar with ? 
 Marine or land, condensing or non-condensing, horizontal, 
 compounds, etc? 5. What defects in engines have come 
 under your notice ? 6. What caused these defects and how 
 were they remedied ? 7. With what description of boilers 
 have you served ? 8. Describe a horizontal tubular boiler. 
 9. Describe a vertical boiler. 10. What boiler defects have 
 come under your notice and how have they been remedied ? 
 ] 1. Have you ever witnessed a steam boiler explosion, and if 
 so, give the cause ? 13. Give the names of the firms for 
 whom you have served or vessels upon which you have been 
 engaged ? 13. What parts of the engine are usually of cast 
 iron ? 14. For what parts of an engine is steel sometimes 
 used? 15. What are hand holes put in boilers for ? 16. How 
 often do you open them ? 17. What is the shape of a man 
 hole cover, and about what is its size ? 18. What is priming 
 in a boiler and what means are taken to prevent it ? 
 
 Note. — A boilermaker says that never before have boiler materials 
 been of better quality than they are to-day. A contrary belief is often 
 expressed ; but modern mastery of steel making has lessened the mar- 
 gin between good steel and inferior steel. The danger with boiler 
 making is not poor steel, but poor workmanship. Badly spaced tubes, 
 rivets and braces, plates too thin for the work, deficient safety attach- 
 ments, and ill-proportioned settings are points where the ignorant or 
 dishonest make a cheap and dangerous boiler. 
 
182 XT. S. RULES FOB SAFETY VAl^VMS, 
 
 U. S. GOVERNMENT RULES FOR THE SAFETY 
 VALVE. 
 
 The following rules issued by the United States Board of 
 of Supervising Inspectors, on account of changes in the rules 
 for granting licenses to engineers of steam vessels, are 
 entirely accurate for use in figuring the different problems 
 relating to the safety valve. 
 
 To find the weight required to load a given safety-valve to 
 blow at any specified pressure. 
 
 1. Measure the diameter of the valve, if is it not known, 
 and from this compute its area exposed to pressure. 
 
 2. Weigh the valve and its spindle. * If it is not possible 
 to do this, compute their weight from their aimensions as 
 accurately as possible. 
 
 3. Weigh the lever, or compute its weight from its dimen- 
 sions. 
 
 4. Ascertain the position of the centre of gravity of the 
 lever by balancing it over a knife-edge, or some sharp-cor- 
 nered article, and measuring the distance from the balancing 
 point to the fulcrum. 
 
 * To find the weight of the valve, spindle, lever, etc., proceed as fol- 
 lows : Take out the valve and spindle and weigh them and make a 
 note of it, then put them back in place, connect the lever and drop it 
 in place resting on the valve spindle, tie a string to the lever directly 
 over the spindle, hook on the scales to the string and weigh the lever, 
 to the weight of the lever add the weight of valve and spindle, or the 
 weight may be found approximately by computatiou. 
 
U. S. RULES FOB SAFETY VALVES. 183 
 
 5. Measure the distance from the center of the valve to 
 the fulcrum. 
 
 6. Measure the distance from the fulcrum to the center of 
 the weight. 
 
 Then compute the required weight as follows : 
 
 1. Multiply the pressure in pounds per square inch at which 
 the valve is to be set by the area of the valve in square 
 inches; set the product aside and designate it "quantity 
 No. 1." 
 
 2. Multiply the weight of the lever in pounds by the dis- 
 tance in inches of its center of gravity from the fulcrum ; 
 divide the product by the distance in inches from the center 
 of the valve to the fulcrum, and add to the quotient the 
 weight of the valve and spindle in pounds ; set the sum aside 
 and designate it " quantity No. 2." 
 
 3. Divide the distance in inches from the center of the 
 valve to the fulcrum by the distance, also expressed in inches, 
 from the center of the weight to the fulcrum ; designate the 
 quotient "quantity No. 3." 
 
 4. Subtract quantity No. 2 from No. 1, and multiply the 
 difference by No. 3. The product will be the required weight 
 in pounds. 
 
 To find the length of the lever, or distance from the fulcrum 
 at tvMch a given weight vnust be set to cause the valve to blow 
 at any specified pressure. 
 
 The area of the valve in square inches, the weight of the 
 valve, spindle and lever in pounds, the position of the center 
 of gravity of the lever, and the distance from the center of 
 
184 U. S. RULES FOB SAFETY VALVE& 
 
 the valve of the fulcrum, must be known, as in the first 
 example. 
 
 Then compute the required length as follows 
 
 1. Multiply the area of the valve in square inches by the 
 pressure in pounds per square inch at which it is required to 
 blow ; set the product aside, and designate it " No. 1." 
 
 2. Multiply the weight of the lever in pounds by the dis- 
 tance in inches of its center of gravity from the fulcrum ; 
 divide the product by the distance in inches from the center 
 of the valve to the fulcrum ; add to the quotient the weight 
 of the valve and spindle ; set the sum aside, and designate it 
 "No. 2." 
 
 3. Divide the distance in inches from the center of valve 
 to fulcrum by the weight of the ball in pounds, and call the 
 quotient " No. 3." 
 
 4. Subtract 'No. 2" from "No. 1," and multiply the 
 difference by "No. 3 "; the product will express the distance 
 in inches that the ball must be placed from the fulcrum to 
 produce the required pressure. 
 
 To find at what pressure the safety valve tmll comncence to 
 hlow when the weight and its position on the lever are known. 
 
 The weight of valve, lever, position of centre of gravity of 
 lever, etc. , must be known as in both the preceding examples. 
 
 Then compute the pressure at which the valve will blow, 
 as follows : 
 
 Multiply the weight of the lever by the distance of Its 
 center of gravity from the fulcrum ; add to this product that 
 obtained by multiplying the weight of the ball by its distance 
 
U. S. RULES FOR SAFETY VALVES. 1S5 
 
 from the fulcrum ; divide the sum of these t-wo products by 
 the distance from the center of the valve to the fulcrum, and 
 add to the quotient so obtained the weight of the valve and 
 spindle. Divide the sum by the area of the valve ; the 
 quotient will be the i-equired blowing-off pressure in pounds 
 pet square inch. 
 
 Example. 
 
 Suppose v^e have a safety valve, with a weight of 50 lbs . 
 suspended 24 inches from the fulcrum ; say the lever weighs 
 6 lbs., gravity center (balancing point) 15 inches from the 
 fulcrum, weight of valve and spindle 2 lbs. , and its center 4 
 inches from the fulcrum, and the diameter of the valve 2 
 inches, at what pressure will the valve open ? Now, then: 
 
 Diameter of valve is 2 inches ; its square is 2x2=4 ; its 
 area is 0.7854x4=3.1416; the weight of the ball is 50 lbs., its 
 distance from fulcrum is 24 inches, and 50x24=1,200 ; the 
 weight of lever is 6 lbs., the center of gravity is 15 inches 
 from the fulcrum, and 15x6=90 ; the weight of the valve is 
 2 lbs., and its distance is 4 inches from fulcrum, and 4x2=8; 
 the area of the valve is 3. 1416, and its center is 4 inches from 
 fulcrum, then 4x3.1416=12.5664, and 1200-1-90+8=1298, and 
 1298 divided by 12.5664=103.3 lbs., or the pressure at which 
 the \alve will open*. 
 
 * The " moment " or leverage of tlie steam, is the total pressure 
 acting upwards, multiplied hy the distance iu inches from the pivot 
 to the valve-stem. The moinent or leverage of the ball acting down- 
 wards ia the total weight of the ball multipled by the distance in 
 toches from the pivot to the center support of the ball. When, there- 
 tore, the moment of the steam, which acts upwards, exceeds both the 
 dead weight of the lever and valve, and also the moment of the ball 
 I>Oldini^ the valve down, then the valve rises and steam escapes. 
 
186 U. S. GOVERNMENT RULES. 
 
 U, S. GOVERNMENT RULES FOR EXAMINA- 
 TIONS OF APPLICANTS FOR ENGINEERS' 
 LICENSES. 
 
 It will be observed that in land service the engineer is ex- 
 amined with reference to his capacity to manage a particular 
 steam plant, especially the steam generating apparatus. He 
 is licensed to have charge of a particular "plant" and for a 
 single year ; but in the marine service, where the examina- 
 tions are conducted by sworn officers of the U. S. Navy, the 
 license is granted without reference to a particular craft, 
 nor is it limited to time, except the candidate is subject to 
 re-examination; the marine licenses, however, vary as to 
 ocean and inland steamers, tug boats, etc. 
 
 Regulations Relating to Marine Engineers. 
 
 1 . Before an original license is issued to any person to aol 
 as engineer, he must personally appear before some local 
 board or a supervising inspector for examination ; but upon 
 the renewal of such license, w^hen the distance f roui any local 
 board or supervising inspector is such as to put the person 
 liolding the same to groat inconvenience and expense to 
 appear in person, he may, upon taking the oath of office be- 
 
ENGINEERS' EXAMINATlONls. 187 
 
 fore any person authorized to administer oaths, and forward- 
 ing the same, togetlier with the license to be renewed, to the 
 local board or supervising inspector of the district in which 
 he resides or is employed, have the same renewed by the 
 said inspectors, if no valid reason to the contrary be known to 
 them; and they shall attach such oath to the stub end of the 
 license, which is to be retained on file in their office. And 
 inspectors are directed, when licenses are completed, to draw 
 a broad pen and red ink mark through all unused spaces in 
 the body thereof, so as to prevent, so far as possible, illegal 
 interpolation after issue. 
 
 3. The classification of engineers on the lakes and sea- 
 board shall be as follows : 
 
 CHIEF. 
 
 Chief engineer of ocean steamers. 
 
 Chief engineer of condensing lake, bay and sound steamers. 
 Chief engineer of non-condensing lake, bay and sound 
 steamers. 
 Chief engineer of condensing river steamers. 
 Chief engineer of non-condensing river steamers. 
 
 Chief engineer of condensing freight, towing, and fishing 
 steamers. 
 
 Chief engineer of non-condensing freight, towing, and 
 fishing steamers. 
 
 Chief engineer of condensing steamers under one hundred 
 tons. 
 
 Chief engineer of non-condensing steamers under one hun- 
 dred tons. 
 Chief engineer of canal steamers. 
 
188 U- S. GOVERNMENT RULES. 
 
 FIRST ASSISTANT. 
 
 First assistant engineer of ocean steamers. 
 
 First assistant engineer of condensing lake, bay, and sound 
 steamers. 
 
 First assistant engineer of non-condensing lake, bay, and 
 sound steamers. 
 
 First assistant engineer of condensing river steamers. 
 
 First assistant engineer of non-condensing river steamers. 
 
 First assistant engineer of condensing freight, towing, and 
 fishing steamers. 
 
 First assistant engineer of non-condensing freight, towing, 
 and fishing steamers. 
 
 First assistant engineer of condensing steamers under one 
 hundred tons. 
 
 First assistant engineer of non-condensing steamers under 
 one hundred tons. 
 
 First assistant engineer of canal steamers. 
 
 SECOND ASSISTANT. 
 
 Second assistant engineer of ocean steamers. 
 
 Second assistant engineer of condensing lake, bay, and 
 sound steamers. 
 
 Second assistant engineer of non-condensing lake, bay, and 
 sound steamers. 
 
 Second assistant engineer of condensing river steamers. 
 
 Second assistant engineer of non-condensing river steam 
 ers. 
 
 Second assistant engineer of condensing freight, towing 
 and. fishing steamers. 
 
 Second assistant engineer of non-condensing freight, tow 
 itig and fislung steamers. 
 
ENGINEERS' EXAMINATIONS. J 89 
 
 Second assistant engineer of condensing steamers under 
 one hundred tons. 
 
 Second assistant engineer of non-condensing steamers 
 imder one hundred tons. 
 
 THIRD ASSISTANT. - 
 
 Third assistant engineer of ocean steamers. 
 
 Third assistant engineer of condensing lake, bay, and 
 sound steamers. 
 
 Third assistant engineer of non-condensing lake, bay, and 
 sound steamers. 
 
 Third assistant engineer of condensing river steamers. 
 
 Third assistant engineer of non-condensing river steamers. 
 
 Third assistant engineer of condensing freight, towing, and 
 fishing steamers. 
 
 Third assistant engineer of non-condensing freight, towing 
 and fishing steamers. 
 
 First, second, and third assistant engineers may act as 
 such on any steamer of the grade of which they hold license, 
 or as such assistant engineer on any steamer of a lower grade 
 than those to which they hold a license. 
 
 Inspectors may designate upon the certificate of any chief 
 or assistant engineer the tonnage of the vessel on which he 
 may act. 
 
 3. Assistant engineers may act as chief engineers on high- 
 pressure steamers of one hundred tons burden and under, of 
 the class and tonnage, or particular steamer for which the 
 inspectors, after a thorough examination, may find them 
 qualified. In all cases where an assistant engineer is per- 
 mitted to act as first (chief) engineer, the inspector shall state 
 
190 V- S. GOVERNMENT RULES. 
 
 on the face of his certificate of license the class and tonnage 
 of steamers, or the particular steamer on which he may so 
 act. 
 
 4. It shall be the duty of an engineer when he assumes 
 charge of the boilers and machinery of a steamer, to forth- 
 with thoroughly examine the same, and if he finds any part 
 thereof in bad condition, caused by neglect or inattention on 
 the part of his predecessor, he shall immediately report the 
 facts to the local inspectors of the district, who shall there- 
 upon investigate the matter, and if the former engineer has 
 been culpably derelict of duty, they shall suspend or revoke 
 his license. 
 
 5. No person shall receive an original license as engineer, 
 or assistant engineer, except for special license on small 
 pleasure steamers of ten tons and under, and ferry boats 
 navigated outside of ports of entry and delivery, who has 
 not served at least three years in the engineer's department 
 of a steam vessel. 
 
 Section 5. (Second paragraph amended.) Provided, That 
 any person who has served as a regular machinist in a marine 
 engine works for a period of not less than three years (not 
 including any time he may have served as an apprentice, 
 may be licensed as an engineer of steam vessels of one hun- 
 dred tons and under, and for inferior grade of license above 
 one hundred tons); and any person who has served for a 
 period of not less than three years as a locomotive engineer 
 stationary engineer, regular machinist in a locomotive or 
 stationary engine works (apprentice machinist in an engine 
 works), and any person who has graduated as a mechanical 
 
ENGINEERS'' EXAMINATIONS. 191 
 
 engineer from a duly recognized school of technology, may 
 be licensed to serve as engineer on steam vessels after having 
 had not less than one year's experience in the engine depart- 
 ment of a steam vessel, which experience must have been 
 obtained within tw^o years preceding the application (which 
 fact must be verified by the certificate in writing of the 
 licensed engineer or master under whom the applicant has 
 served, said certificate to be filed with the application of the 
 candidate), and no person shall receive license as above, 
 except for special license, who is not able to determine the 
 weight necessary to be placed on the lever of a safety valve 
 (the diameter of valve, length of lever, and fulcrum being 
 known) to withstand any given pressure of steam in a boiler, 
 oi' who is not able to figure and determine the strain brought 
 on the braces of a boiler with given pressure of steam, the 
 position and distance apart of braces being known ; such 
 knowledge to be determined by an examination in w^riting 
 and the report of the examination filed with the application 
 in the office of the local inspectors, and no engineer, or 
 assistant engineer now holding a license shall have the grade 
 of the same raised without possessing the above qualifi- 
 cations. 
 
 And no original license shall be granted any engineer, oi 
 assistant engineer, who cannot read and write, and does not 
 understand the plain rules of arithmetic. 
 
 The Secretary of the Treasury has issued the following 
 rules concerning the examination of applicants for the posi- 
 tion of second assistant engineer in the United States revenue 
 marine. 
 
192 U. S. GOVERNMENT RULES. 
 
 A candidate for an appointment as second assistant 
 engineer must not be less than twenty-one nor more than 
 thirty years of age ; he must be of good moral character and 
 correct habits ; he must have worked not less than eighteen 
 months in a machine shop and have had responsible charge 
 of a steam engine, or else have served not less than that 
 period in charge or assisting in the care and management 
 of the machinery of a steam vessel in active service. Upon 
 examination, he must be able to describe and sketch all 
 the different parts of the marine steam engine and 
 boilers, and explain tlieir uses and mechanical operation, 
 the manner of putting thena in action, regulating their 
 movements, and guarding against danger. He must write 
 a fair legible hand, be well acquainted with arithmetic, 
 simple mensuration, English orthography and composition, 
 also with rudimentary mechanics and its practical appli- 
 cations; he must possess some skill in the use of ordinary 
 hand tools, and have a fair practical knowledge of the 
 nature of heat and steam, of the general laws in relation 
 to the expansion of steam, of the uses of the indicator and 
 interpretation of diagrams, of the chemistry of combustion 
 and corrosion, of the composition of sea water and uses of 
 the salinometer, and of the usual calculations to determine 
 loss by blowing, gain by heat, and water necessary for con- 
 densation. 
 
 No person otherwise qiialified will be commissioned as an 
 engineer before he has shown his ability to perform duty at 
 sea in a satisfactory manner for a period of at least six 
 months. This service may either antedate or be g,cc[uired 
 subsequent to an examination. 
 
ENGIl^EERS' EXAMINATIONS. 193 
 
 No person will be originally appointed to a higher grade 
 than second assistant engineer, not until he shall have passed 
 a i^hysical and professional examination. The j)hysical ex- 
 amination shall preceed the professional, and if a candidate 
 be rejected physically, he will not be examined further. All 
 professional examinations will be competitive in character, 
 and applicants, who pass the minimum standard required in 
 several subjects, will be placed upon the list of persons elig- 
 ible for appointment, in the order of the excellence of their 
 examinations, respectively. From this list appointments 
 will be made in regular order, as vacancies may occur, until 
 another examination. 
 
 No person will be designated for examination until he has 
 filed in the department the necessary certificates showing his 
 proper qualifications as to character, habits, and time or 
 times of service, and the ability that has been displayed dur- 
 ing such service. 
 
 Any person producing a false certificate of age, time of 
 service, or character, of making false statement to a board 
 of examination, will be dropped immediately. 
 
 Any person who, subsequent to his examination, may be- 
 come disqualified from moral considerations, will not be 
 appointed. 
 
194 CITY ORDINANCE. 
 
 (MODEL OF) 
 
 CITY ORDINANCE RELATING TO ENGINEERS' 
 LICENSES. 
 
 The following is given as a model of city regulations re- 
 quiring examinations, and as nearly all State and city laws 
 are substantially alike, this may suffice to indicate the legal 
 requirements to be conformed to by the applicant. The full 
 text of the law here given shows very clearly the responsi- 
 bility of the system of licensing an engineer and the gravity 
 with which it is regarded by the public : 
 
 Sec. 388. Any person desirous of being employed to take 
 charge and control of any stationary engine, steam boiler, or 
 other steam generating apparatus within the city of Cleve- 
 land, shall apply to the Examiner of Engineers for a blank 
 application, which shall have been prepared by said Exami- 
 ner of Engineers. 
 
 After said applicant shall have filled out said blank appli- 
 cation, and shall have caused the same to be signed by three 
 (3) reputable stationary engineers, who shall have obtained 
 previously a license for said employment, he shall then apply 
 to the said Examiner of Engineer^, to be examined by the 
 said Examiner of Engineers touching his qualifications for 
 
ENGINEERS' EXAMINATIONS. 195 
 
 such employment, and if the said Examiner of Engineers, 
 after having made an examination, shall have found said 
 applicant possessed of the necessary qualifications for said 
 employment, he shall give said applicant a certificate to that 
 efliect. 
 
 On presentation of such certificate to the City Clerk, and 
 the payment to said clerk of the sum of fifty (50) cents for 
 the first issue of a license and twenty-five (25) cents for each 
 subsequent issue thereof by such applicant, the said clerk 
 shall issue to such applicant a license imder the seal of said 
 city, authorizing such applicant to take charge and control 
 of a stationary engine, steam boiler, or other apparatus for 
 generating steam, for the period of one year from the date of 
 its issue, and the said clerk shall pay all moneys so received 
 by him into the treasury of said city, to the credit of the 
 general fund, provided, however, that said Examiner of 
 Engineers shall issue no such license to any applicant who 
 shall not have had one (1) year's practical experience in said 
 employment, except in private dwelling houses. 
 
 Sec. 389. It shall be unlawful for any person or persons 
 to take charge and control of any stationary engine, steam 
 boiler, or other apparatus for generating steam, except in 
 private dwelling houses, without having a license to do so, 
 as provided in the foregoing section, which license shall be 
 exposed to view in a conspicuous place in the room or place 
 containing the boiler, generator, or engine of which such 
 person is in charge ; provided, however, that all licenses 
 heretofore issued in pursuanc*^ of said original ordinance shall 
 continue in force for the period for which they were issued. 
 
196 CITY ORDINANCE. 
 
 It shall be unlawful for any person or persons, partnership 
 or association, company or corporation, knowingly to employ 
 or keep in their employ for the purpose of taking charge and 
 control of any stationary engine, steam boiler, or other 
 apparatus for generating steam, except in private dwelling 
 houses as aforesaid, any stationary engineer or other person 
 who has not been licensed as above provided and required. 
 
 Sec. 390. It is hereby made the special duty of every 
 police officer or patrolman, and the superintendent of police 
 is hereby instructed to give the said Examiner of Engineers 
 all possible assistance to enforce the provisions of this chapter, 
 and for this purpose the police shall have authority to enter 
 any shop, factory, mill, store, warehouse, hotel or other 
 building or structure in which a steam boiler or engine is 
 located, and to demand to be shown the license of the engi- 
 neer having charge of said steam boiler or engine. 
 
 Sec. 391. Whoever violates any of the provisions of this 
 chapter shall be subject to prosecution before the Police 
 Court of said City, and on conviction thereof be fined in any 
 sum not less than ten dollars nor more than twenty dollars 
 for the first offense, and not less than twenty dollars nor 
 more than fifty dollars for the second and each subsequent 
 offense. 
 
INSPECTION OF STEAM BOILEBS- 197 
 
 LAWS RELATING TO THE INSPECTION OF 
 STEAM BOILERS. 
 
 According to the laws of the State, every owner, agent or 
 lessee, of a steam boiler or boilers, in the City of New York, 
 shall annually report to the board of police, the location of 
 said boiler or boilers, and, thereupon, the officers in command 
 of the sanitary company shall detail a practical engineer, who 
 shall proceed to inspect such steam boiler or boilers, and all 
 apparatus and appliances connected therewith. 
 
 When a notice is received from any owner or agent that 
 he has one or more boilers for inspection, a printed blank 
 is returned to him stating that on the day named therein 
 the boilers will be tested, and he is asked to make full pre- 
 paration for the inspection by complying Avith the following 
 rules : 
 
 Be ready to test at the above named time. 
 
 Have boiler filled with water to safety valve. 
 
 Have 13^ inch connection. 
 
 Have steam gauge. 
 
 Steam allowed two-thirds amount of hydrostatic pressure. 
 
198 INSPECTION OF STEAM BOILERS. 
 
 The following have also been adopted by one or more 
 Inspection Companies: 
 
 How to Prepare for Steam Boiler Inspection. 
 
 1. Haul fires and all ashes from furnaces and ash pits. 
 
 2. If time will permit, allow boiler and settings to cool 
 gradually until there is no steam pressure, then allow water 
 to run out of boilers. It is best that steam pressure should 
 not exceed ten pounds if used to blow water out. 
 
 3. Inside of boiler should be washed and dried through 
 manholes and handholes by hose service and wiping. 
 
 4. Keep safety valves and gauge cocks open. 
 
 5. Take off manhole and handhole plates as soon as possible 
 after steam is out of boiler, that boiler may cool inside suili- 
 ciently for examination ; also Tceep all doors shut about 
 boilers and settings, except the furnace and ash pit doors. 
 Keep dampers open in pipes and chimneys. 
 
 6. Have all ashes removed from under boilers, and fire 
 surfaces of shell and heads swept clean. 
 
 7. Have spare packing ready for use on manhole and hand- 
 hole plates, if the old packing is made useless in taking off or 
 is burned. The boiler attendant is to take off and replace 
 these plates. 
 
 8. Keep all windows and doors to boiler room open, after 
 fires are hauled, so that boilers and settings may cool as 
 quickly as possible. 
 
 9. Particular attention is called to Eule 5, respecting doors 
 — ^which should be open and which closed — also arrangement 
 
INSPECTION OF STEAM BOILEHH. !»« 
 
 of damper. The importance of cooling the inside of the 
 boiler by removal of manhole and handhole plates at the 
 same time the outside is cooling, is in equalizing the process 
 of contraction. 
 
 Issuing CertiGcates. 
 
 These conditions having been complied with, the boiler is 
 thoroughly tested, and if it is deemed capable of doing the 
 work required of it, a number by which it shall hereafter be 
 known and designated is placed upon it in accordance with 
 the city ordinance : Failure to comply with this provision is 
 punishable by a fine of $25. A certificate of inspection is 
 then given to the owner, for w^liich a fee of §2 is paid. 
 
 Tills certificate sets forth that on the day named the boiler 
 therein described was subject to a hydrostatic pressure of a 
 certain number of pounds to the square inch. The certificate 
 tells where the boiler was built, its style or character and 
 ' ' now appears to be in good condition and safe to sustain a 
 
 working pressure of to the square inch. The safety 
 
 valve has been set to said pressure." A duplicate of this 
 certificate is posted in full view in the boiler room. In case 
 the boiler does not stand the test to which it is subject, it 
 must be immediately repaired and put in good Avorking order 
 before a certificate will be issued. 
 
 AppHcants for licenses are very liable to be asked — to test 
 their experience in and around steam boilers — some questions 
 relating to their inspection ; hence the value of these extracts 
 upon the subject. 
 
aOO CBIEF INSPECTOR'S BEPOBTS. 
 
 IMPORTANT. 
 
 The following tea pages are undoubtedly the raost 
 valuable and instructive of any same number of pages 
 in this volume. They indicate the path of advance in 
 granting licenses for the future, and, with admirable 
 modesty, the great benefits which have accrued from a 
 wise and faithful administration of j)ublic law, con- 
 trolHng engineers' examinations and the granting of 
 licenses. It will be happier times when the whole 
 country is equally guarded and protected. 
 
 STEAM BOILER INSPECTION AND CERTIFI- 
 CATION OF ENGINEERS. 
 
 BY THE SUPERINTENDENT, DEPARTMENT BOILER INSPECTION 
 BROOKLYN, N. Y. 
 
 {Extract.) 
 In the city of Brooklyn the insiDection of boilers is made 
 by a corps of six inspectors. The hydrostatic test is apphed, 
 and wherever deemed necessary, a hammer test is added. 
 Whenever defects are ascertained, they are caused to be 
 remedied or the boiler condemned. 
 
 The inspection of steam boilers and the certification of 
 engineers to manage and care for the same are subjects to 
 which much thought has been given by the best engineers of 
 the country. From the inception of the general idea of 
 official boUer inspection to the present date, gr'at strides 
 
CERTIFICATION OF ENOmEEIiS. 201 
 
 have been made by both national, state and municipal gov- 
 ernments in bringing tlie system to perfection, and to throw 
 around boilers under their supervision every safeguard that 
 human ingenuity could devise. 
 
 The United States government, through its able corps of 
 naval engineers, has done much to advance the interests of 
 those engaged in this work, having systematized the \vork so 
 that the best possible results are attained with the material 
 at hand. The individual states are also gradually falling 
 into line and are enacting laws provic^ing for the needed 
 inspection. 
 
 In the cities of New York and Brooklyn the laws govern- 
 ing boiler inspection are similar in general principle, while 
 differing in some of the particulars. In both cities the 
 bureaus of inspection are a branch of the j)olice dapartment, 
 responsible to the commissioner or commissioners of police. 
 In the former city, officers are detailed for this work from 
 the police force, after having given satisfactory evidence of 
 their qualification for this duty, and are under a command- 
 ing officer of experience and discretion. 
 
 In the city of Brooklyn, while the inspectors are not 
 members of the force, they are entitled to all the privileges 
 and subject to the same discipline. The superintendent of 
 steam boilers is a position provided for by statute, the quali- 
 fications for which are set forth explicitly, and the duties and 
 authority expressed in such laws. The examination and 
 grading of engineers is discretionary with him, and the 
 steam plants in the city are classified and recorded in liis 
 office. The aim and desire of the department is to assist anJ 
 
202 CERTIFICATION OF ENGINEERS. 
 
 encourage the best skill among our engineers, thereby aiding 
 the worthy and deserving men, as well as to provide for 
 Bteam users the best material for the management of their 
 several steam plants. 
 
 The Association of Boiler Inspectors of the United States 
 and Canada, following the example set by the United States 
 inspectors, hold annual meetings for the interchange of views 
 and opinions as to the best method of boiler inspection. They 
 have adopted rules which, while not legally binding upon its 
 members as are the rules of the latter body, yet place a moral 
 obligation for the carrying out of the same. 
 
 It is our proud privilege to he able to say that since tlie 
 institution of the inspection of steam boilers in this city, 
 there has been no explosion of a steam boiler that had prev- 
 iously been inspected by the department. 
 
 The inspectors are always on the alert, and arrests are fre 
 quently made for violation of our laws, and the courts by 
 their actions sustain and strengthen the hands of the depart 
 ment in enforcing the law. • 
 
 The engineers of this city are of great assistance to the 
 department in the care of their several plants, and are ever 
 ready to assist the department in its work. The steaur users 
 as well recognize the importance of the work, and it is the 
 desire of the department while enforcing the law to conserve 
 their interests wherever practicable. There are some imper- 
 fections in our laws that might be corrected, and some action 
 will be taken in that direction to the betterment of the 
 department and the perfection of the work. 
 
 J^'Y, 1895. W A. POWERS, 
 
CHTEJf TNSPECTOWS REPORTS, 
 
 SPECIAL REPORT 
 
 OF THE 
 
 NE^i.' York City Steam Boiler Inspection and Engineers' 
 Bureau, Jan. 1, 1895, 
 
 ON 
 
 Boiler Inspection and the Ljcenslno of Engineers. 
 
 In the last annual report from this bureau the inadequacy 
 of the present method of boiler inspection was commented 
 
 There are but few engineers in New York City who have not met 
 Sergeant Washington MuUin, Chief of the Boiler Inspection and 
 Engineer's Bureau, of New York City. Thousands of engineers know 
 him at sight. For the henefit of those who have not had the pleasure 
 of meeting him we herewith present a brief sketch of his active life : 
 
 Officer MuUin was born in the City of Philadelphia, Sept. 29th, 
 1837. His parents removed to New York City when he was but eight 
 years of age, and he attended the public schools until he had reached 
 his sixteenth year, when he was apprenticed In the engine and 
 machine works of Abraham Van Ness, where he was working at the 
 breaking out of the war. Young Mulliu was among the first to 
 respond to his country's call, and assisted in organizing Company "E," 
 73d N. Y. Volunteers. He participated in all of the engagements in 
 which his brigade took part ; was promoted to first lieutenant, and 
 honorably discharged September, 1864; was appointed to the Police 
 Department, New York City, September, 1864, promoted to roundsman 
 Oct., 1865, to sergeant 1808, and subsequently assigned as Chief of thti 
 Boiler Inspection and Engineer's Bureau, February, 1883. 
 
 Schooled as a soldier, he is a strict disciplinarian ; uses mscretion 
 in the examination of the many thousand engineers who come before 
 him annually to pass the examination preparatory to taking out the 
 engineer's license required by law ; never discriminates, treats all 
 applicants alike, shows no favoritism, and the engineer who obtains a 
 license must pass the necessary examination in a satisfactory manner, 
 proving his ability to take charge of and operate a steam plant. The 
 competent have nothing to fear in Sergeant Mullin — the ignorant, 
 incompetent and intemperate are always rejected. 
 
 The EnQineer^e List, Jan. '86, 
 
'^04 SPECIAL REPOBT—IMfOKTANT, 
 
 upon, and recommendations made for a change in the laws 
 to improve the system, to the end that the protection to life 
 and property be made more secure, and the dangers from 
 such casualties as boiler explosions reduced to a minimum. 
 
 While there were several bills presented to the last Legisla 
 ture, touching upon the matter of boiler inspections and 
 licensing of engineers, none seemed to meet with approval, 
 and all failed of passage. 
 
 Therefore, it is again respectfully submitted that, in con- 
 sequence of the danger to life and property, attendant upon 
 the operation of steam boilers, it would seem that no difficulty 
 should be encountered in the endeavors made to have them 
 legally regulated as to their proper and careful construction 
 and inspection, as well as to the licensing of those who are 
 to have charge and operate them, more especially in locali- 
 ties which are thickly populated, and where an explosion of 
 a steam boiler means dire disaster. 
 
 As a flatter of comparison hetiveen the different places in 
 the United States, where there are inspection laivs and where 
 no legal supervision exists, it will he noted that the casual- 
 ties resulting from boiler explosions are as one to a hundred. 
 If the importance of tliis matter was properly and intelli- 
 gently impressed upon the consideration of those selected 
 to make the laws, and more stringent safeguards were drawn 
 around the la^t^s and ordinances now in force, a much greater 
 percentage would be shown in favor of legal supervision. 
 
 The boiler- inspection laws now in operation in the cities 
 of New York and Brooklyn, as far as the particular method 
 of inspection is concerned, are the same as those existing in 
 
SPECIAL REPORT-IMPORT Ay T. 205 
 
 1862, when not more than 2,000 steam boilers were operated 
 in the then metropolitan district, comprising the counties of 
 New York, Kings, Richmond and parts of Queens and West- 
 chester, while now there are uj)ward of 8,000 boilers in use 
 in the City of ITew York alone. 
 
 At the time mentioned, and for some years after, the aver- 
 age pressure used to operate steam boilers was about fifty 
 pounds to the square inch, whereas, at jjresent, owing to the 
 advancement and improvements made in machinery and 
 other devices necessary for steam to operate have been so 
 great that the average pressure carried will equal 100 pounds 
 to the square inch, and yet, withal, no legal advancement 
 has been made in the matters regulating the testing and in- 
 spection of boilers. To be sure, reputable manufacturers 
 and builders of steam boilers take the necessary precaution 
 in building boilers required to withstand this extra demand 
 for increased pressure, but it is to guard against that class of 
 firms who construct cheap work, taking chances on the 
 safety and security of the boilers they make, that more rigid 
 laws should be enacted. 
 
 Such laws should provide that every maker of a boiler 
 should issue or give a certificate, setting forth the quality 
 and thickness of the material used, its guaranteed tensile 
 strength and ductility, the pressure per square inch the boiler 
 is designed to carry, and every particular concerning its con- 
 struction, and that in the absence of such certificate the ten- 
 sile strength of the material should be calculated at 40, 000 
 lbs. for iron and 50,000 lbs. for steel plates, when determin- 
 ing the safe working pressure. 
 
806 SPECIAL. REPORT— IMPORTANT. 
 
 The strength and security of a boiler should be determined 
 by a series of calculations, based upon established rules, upon 
 its various parts, and, when the workmanship and material 
 is found to be of good quality, a factor of five should be the 
 standard used to determine the safe working pressure to be 
 allowed. 
 
 But, in the matter of inferior workmanship or inferior 
 material, authority should be given the inspector to either 
 condemn the boiler or increase the factor to a degree that 
 would insure the utmost safety in the operation of the boiler. 
 Then, again, every boiler should be subjected to a hydrostatic 
 test before put in actual operation, such a test to be made at 
 least once every year thereafter, and in the following 
 manner : 
 
 The boiler to be filled entirely with water, a fire lighted in 
 the furnace, and the temperature of water brought to at 
 least 150 degrees of Fahrenheit, when the boiler should be 
 subjected to a hydrostatic j)ressure of one and one-half times 
 the steam or working pressure to be allowed per square inch. 
 The inspector, after applying the hydrostatic test, should go 
 inside the boiler and make a thorough examination of every 
 part of the same, and, if the test is not satisfactory, the de- 
 fects should be made good, and the boiler re -tested. 
 
 In water-tube boilers, constructed to carry 150 lbs. or more, 
 where the factor of safety is generally above seven, the 
 pressure should be one and one-quarter times the working 
 pressure to be allowed, for the reason that pressure above 
 225 lbs. will rupture calking in longitudinal seams of steam 
 ixunus. 
 
SPECIAL BEPOBT-TIUPORTANT. 307 
 
 In determining the working pressure for boilers that have 
 been several years in use, the inspector should take into con- 
 sideration the age and condition under which it has been 
 operated, as well as the thickness, original strength, efficiency 
 of riveted joints, etc., and make calculation between what 
 was its safe working pressure when new, and the pressure 
 now desired, and he should make due allowance for deterio- 
 ration, and, if necessary, drill holes to properly determine its 
 thickness. 
 
 All boilers should have a composition valve or cock placed 
 in the feed line, between the check valve and the boilei% so 
 as to permit of overhauling the check when steam is up, if 
 necessary. All pipe connections of over one inch internal 
 diameter should be attached to the boiler by a flanged joint, 
 riveted or bolted. Each boiler should have three gauge cocks 
 and a water glass, and the gauge cocks and water column 
 should be connected directly to tlae boiler with at least one- 
 inch pipe, the lower water pipe to be tapped near the bottom 
 of the boiler, and the upper steam pipe connected at the top 
 of the boiler, and as far away from where the main steam 
 pipe is connected as is practical. 
 
 No other connection should be allowed to be taken from it. 
 A blow cock should be placed at the bottom of the lower 
 water pipe. The bottom gauge cock should be placed at least 
 t^vo inches above the highest heating surface, and the other 
 cock placed in proper proportions, so as not to unduly reduce 
 the intended steam tipace. 
 
 Each boiler should have a steana gauge that avouM cor 
 rectly indicate one-and-a-half times the working pressure 
 
30B SPECIAL REPORT— IMPORTANl. 
 
 allowed, and one safety valve of sufficient capacity, when 
 open, to carry off all the steam the boiler could generate with 
 all the other valves closed. 
 
 The blow-off pipe on horizontal tubular boilers, when at- 
 tached to the back connection or combustion chamber, should 
 be of ample size, but not to exceed two inches internal diam- 
 eter, and should be of extra heavy pipe, with malleable fit- 
 tings, and protected from the intense heat by a metal sleeve 
 or other covering, and, in the absence of such covering, there 
 should be a circulating pipe connected with the upper part 
 of the boiler to give good circulation and eliminate the 
 danger attending the dead end between the blow cock and 
 boiler. There should also be a surface blow-off. 
 
 All high pressure boilers of the vertical or locomotive style 
 should have a fusible plug placed in the crown sheet. 
 
 Boilers should have two ways of feeding — by a steain pump 
 and by an injector ; pumps to be used only when hot water 
 is available or the injector out of order. When two or more 
 boilers are connected, the inspectors should give particulai 
 attention to the connection in the main steana pipe, and see 
 that due allowance is made for expansion. 
 
 That a proper record of each boiler may be kept, and that 
 it could be at all times easily identified, a plate, bearing the 
 official record number of the boiler, should be securely and 
 permanently fastened to the boiler in a conspicuous place. 
 
 It should be made the duty of engineers in charge of steain 
 boilers, to blow, or cause to blow, at least once each day, the 
 safety valve to insure its readiness for iise, and should a 
 
SPECIAL REPORT— IMPORTANT. 209 
 
 safety valve be found, at the annual inspection, to have been 
 tampered with or out of order, the certificate of the person 
 in charge should be suspended or revoked. 
 
 Provision should also be niade_that would require an engi- 
 neer to go inside his boiler, at least once in three months, to 
 cleanse the same, and see that no accumulation of scale or 
 corrosion had taken place. By this means the property of 
 his employer will be protected, the life of the boiler pro- 
 longed, and the loss to life and property averted. 
 
 These are mentioned as some of the provisions that should 
 be embodied in a law which, when drafted, would cover the 
 necessary requirements more in detail, and which would 
 surely meet the approval, and ultimately result to the bene- 
 fit, of owner, steam user, engineer, and everybody in any 
 way concerned or interested in the use of steam, or the safety 
 JO life and property. Respectfully submitted, 
 
 WASHINGTON MTT TTTTM 
 
210 HA WKINS' AIDS. 
 
 insriDEix: 
 
 Hawkins' Aids to Engineers' Examinations. 
 
 Absolute pressure of steam a.. « 62 
 
 Absorber, tlie .. 140 
 
 Absorption (the) Bystem defined 146 
 
 Action of injector 119 
 
 Action of pump described 106 
 
 Addition of decimals 168 
 
 Advantages of compounding 80 
 
 Agitator (the) use of , 147 
 
 Air for combustion ; how supplied 49 
 
 Hot ; not good to supply furnace • 49 
 
 Machines described 149 
 
 Objections to 149 
 
 Standard for speciflo gravity , 134 
 
 Weight of ; under pressure in a boiler. 61 
 
 Alloy, definition of 26 
 
 Ammonia, advantages of. 143 
 
 Anhydrous 143 
 
 Aqua. 147 
 
 Cycle of compression, condensation, expansion 147-148 
 
 Pump defined 146 
 
 Receiver 146 
 
 Appliances for the operation of a steam boiler. 88 
 
 Aqua ammonia defined 147 
 
 Area of pump pistons 112 
 
 Arithmetic, summary of 166 
 
 Arithmetical signs 165 
 
 Calculations, unit of.. 154 
 
 Prosrression 178 
 
 Automatic cutoff of engines 68 
 
 A well arranged Index doubles the value of a scientific and 
 mechanical work ; it is like a guide post to a traveller journeying 
 through an unknown country. A good index tells very quickly the 
 entire contents of a book— it not only gives the page where particular 
 information is to be found, but it forcibly indicates to the student 
 those items of necessary knowledge of which he is ignorant and 
 which It is best for him to "study up." 
 
INDEX. 211 
 
 Back press\ire 74 
 
 Valve 85 
 
 Ball valve 85 
 
 Baseline 123 
 
 Bearing bars 58 
 
 Bismuth, speciflc heat of 153 
 
 Bituminous coal, how toflre 43 
 
 Combustion of 48 
 
 Lbs. of water evaporated from and at 213° 50 
 
 Units of heat of combustion 50 
 
 Boiler braces and stays 29 
 
 Fittings 83 
 
 Materials 23 
 
 Plates, qualifications for 24 
 
 plate, thinnest it is desirable to use 53 
 
 Rule to find capacity of 116 
 
 Steam, description .... 21 
 
 Tests 140 
 
 Tubes, how to estimate the diameter of 86 
 
 Boiling, irregularity of 140 
 
 Process of 63 
 
 Braces, arrangement of, in a boiler 31 
 
 How best to make repairs 33 
 
 Materials of which made 81 
 
 Questions and answers relating to 29 
 
 Stays 29 
 
 Stress allowed on 33 
 
 Brass, specific gravity of 137 
 
 Brick, speciflc gravity of 137 
 
 Brine system of refrigeration 144 
 
 System, how the brine is circulated 145 
 
 Tank, how arranged 144 
 
 Brush (in electricity) defined 133 
 
 Brushes ; important rule regarding 133 
 
 Butt-joint, description 56 
 
 Calculations for safety valve 93-97 
 
 Of expansion and contraction of steam boilers 28 
 
 Of strength of seam of steam boiler 56 
 
 Power of steam engine 79 
 
 The mean effective pressure 79 
 
 rapacity of boiler ; rulefor 116 
 
 Capacity, safe rule for pump, 109 
 
 Of steam pump 113 
 
 Of water cylinder 113 
 
 Carbon, units of heat of combustion 60 
 
 Lbs. of water evaporation at 213° 50 
 
 Card, indicator 121 
 
 Caulking, definition of 53 
 
 Centigrade thermometer, description. 153 
 
 Certificates, issuing 199 
 
 (new)granted inN.Y ix 
 
 (refused) in N. Y. City is 
 
 Renewed in N. Y. City La 
 
 OhiiTCoal, specifio gravity of 137 
 
 Check valve 85 
 
 Chemical law on which the absorption system is based 147 
 
 Chemical refrigeration 142 
 
 Chief engineer, rank of. 187 
 
 Otrculation of water in boiler, cause of 46 
 
 Crty Ordinance relating to englnaers' licenses, /model of) 144 
 
212 tLAWKLN^ 4J3aS. 
 
 Classes of engines ; f8 
 
 Of compound engines ....^...^,. . jou 
 
 Of levers •••• ^i 
 
 Classification of knowledge the key to success .17 
 
 Of steam engines ^^o 
 
 Cleaning a Are, way of - • • 43 
 
 Clearance defined j^ 
 
 Coal, bituminous, how to fire •••;•- J" * Vi;oo tX 
 
 Bituminous, lbs. of water evaporated from and at 213° 50 
 
 Bituminous, units of heat of combustion 50 
 
 Combustion of 5° 
 
 Hard, units of heat of combustion 5o 
 
 Hard, lbs. of water evaporated from and a 1 213° ^ 
 
 Hard, how to fire .*^ 
 
 How much " cold " in a lb. of J-** 
 
 In furnace ; thickness of bed of 4d 
 
 Progress in economical use °° 
 
 Specific heat of ... 15d 
 
 Specific gravityof -i^ 
 
 Cock; definition of a °5 
 
 Gauge. 
 
 42 
 
 Cohesion defined ^^ 
 
 Of water 5^ 
 
 Coke, burns after gas in combustion. |^ 
 
 Lbs. of water evaporated from and at 213° 50 
 
 Total units of heat of combustion 50 
 
 Cold, effect on iron -^ 
 
 How much in a lb. of coal ■'^** 
 
 Cold-short iron or steel fv 
 
 Combustible, definition °i 
 
 Combustion of bituminous coal *? 
 
 Chamber, essentials of ^\ 
 
 Process of ***• ^;^ 
 
 Table of heat of 50 
 
 Commutator defined |?^ 
 
 Composition of water '-^ 
 
 Compound engines, description of ^ 
 
 Eule to calculate horse power .... ou 
 
 Compounding, advantages of °^ 
 
 Compressor, double-acting l** 
 
 Condenser defined.... ^j2 
 
 Submerged and open air -L^J 
 
 Condensing engines. •• rS 
 
 Howtomanage '° 
 
 Conductor ; definition of j~5 
 
 Varietiesof. \^ 
 
 Conservation of energy ^^ 
 
 Constituents of steam -Sji 
 
 Construction of a dynamo ••• ^^ 
 
 Of steam boilers °5 
 
 Contraction and expansion of steel boilers «^ 
 
 Cooling tank ( the > j^ 
 
 Copper, specific heat of ■ |o2 
 
 Specific gravity of « ^2i 
 
 Corliss (The) Engine .°' 
 
 Corliss engine valves ; how to set •■•' * 
 
 Corliss valve, illustration .-^ 
 
 Covering steam pipe ; importance of -i^l 
 
 Crank ; object of the id 
 
 Crowfoot brace. -or 
 
 Cnmhing strength defined • • "*• 
 
INDEX. 213 
 
 Cycle or circle of ammonia 147 
 
 Cylinder ; definition of 75 
 
 Condensation, how to remedy 77 
 
 Clearance in 70 
 
 Water in, efEect of 74 
 
 Dead centers of engines 88 
 
 How to pass, witiiout jarring 88 
 
 Dead steam 59 
 
 Decimals 166 
 
 Bed cation of the work iii 
 
 Defective diagram . 135 
 
 Diagram, defective 125 
 
 Diagram of an indicator 123 
 
 Results ohtained hy an indicator diagram 123 
 
 Diameter of different tubes ; how to ascertain 86 
 
 Difference between pump and injector 117 
 
 Between steel and iron ■ 26 
 
 Direct acting duplex pump 113 
 
 Direct acting steam pump Ill 
 
 Direct expansion system 144-145 
 
 Di\'ision of decimals 169 
 
 Double acting compressor, defined 149 
 
 Double acting engines 65 
 
 Double acting pump 107 
 
 Double injectors 119 
 
 Double riveting 53 
 
 Drain cocks ; liow to manage 78 
 
 Drainage of pipes 86 
 
 Dry steam 59 
 
 Dry steam as a conductor = 104 
 
 Ductility, definition of 23 
 
 Duplex pumps ; direct acting 113 
 
 Duplex pump ; rule for setting 179 
 
 Duplicate parts, advantage of keeping on hand 83 
 
 Durability oi engines , 69 
 
 Duties of a slide-valve 73 
 
 Dynamos, construction of 130 
 
 bynamo-electrio machine 130 
 
 Dynamo ; general construction 130 
 
 Dynamo "■ trouble," 133 
 
 Eccentric ; how to adjust on a new shaft ^ 75 
 
 Economy in production of steam 66 
 
 Ofsteam 69 
 
 Effect of water in cylinder 74 
 
 Effect on particles of water changing it to steam 63 
 
 Effective Horse Power (E. H. P.) 138 
 
 Elastic limit, definition of 23 
 
 Electric current 127 
 
 Electricity, and electric m.achines ; questions and answers relat- 
 ing to 126 
 
 For engineers 126 
 
 Kindsof 128 
 
 Electric machines and circuits ; how to keep in order 130 
 
 Electro magnet 131 
 
 Elementary questions by the examining engineer 180 
 
 Elongation of iron and steel , 52 
 
 Of metals 80 
 
 Energy, definition of 153 
 
 Engine (Steam). 64 
 
 Engine and boiler fittings , 83 
 
 Condensing, how to manage 78 
 
M14 OA.WKINS' AIDS. 
 
 Engine, Componnd 74 
 
 Difference in high and low pressure 74 
 
 Fixtures ; questions and . answers relating to 83 
 
 How to pass dead center 88 
 
 Slide valve, how to reverse motion 75 
 
 Taking charge of new 88 
 
 What to do before starting an 78 
 
 Engines, automatic 68 
 
 Clearance 70 
 
 High speeds 67 
 
 Pumping 112 
 
 Simplicity desirable 68 
 
 The Corliss 67 
 
 Throttling 68 
 
 Engineers' examinations, N. Y. City ix 
 
 Engineers' certificates renewed in N, Y. City ix 
 
 Engineers' licenses; City Ordinance relating to 194 
 
 Brooklyn, N. Y., official report 200 
 
 Offlcialreport 2<)3 
 
 Engineers' licenses * tfecessary quallhcations to secure 13 
 
 Equalizer (the) 146 
 
 Evaporation per lb. coal in ordinary boiler 40 
 
 Examination, conducted by oneself 180 
 
 Examinations of applicants for U. S. Government engineers' 
 
 licenses ; Kules ^'or 186 
 
 Example for rule V. fc>. marine examination 185 
 
 Exhaust-lap 71 
 
 Exhaust line *. . 121 
 
 Ports, definition 76 
 
 Steam injector 119 
 
 Expansion eugines, principles on which they work 81 
 
 Expansion and contraction of boilers 27 
 
 How to avoid dangers of 28 
 
 ^ixedand movable 73 
 
 Of steam 5 gain in the use of. 104 
 
 Of water an changing to Bteam 60 
 
 Of steam, according to pressure 60 
 
 Expansion line 121 
 
 Expansion valve 147 
 
 Explosions, great cause of boiler 41 
 
 Extract from N. Y. Laws relating to qualifications 14 
 
 Factor of safety for fittings 86 
 
 In figuring strength of steam boiler 57 
 
 Fahrenheit's thermometer, description 152 
 
 Feed pump ; design of a . 114 
 
 Fire surface of a boiler ; how proportioned 157 
 
 Firing ; Rules for 45 
 
 First assistant engineers 188 
 
 Fittings for engines and boilers 83 
 
 Flange ; definition of boiler 53 
 
 "Flashing" ; because of 133 
 
 Flow of electric currents 128 
 
 Flywheel 88 
 
 Fly wheel, not needed in locomotive and marine engines 88 
 
 Foot-pounds in a H. P 138 
 
 Force of expansion ; how to calculate 28 
 
 Freezing point 153 
 
 Freezing tank (the) 146 
 
 Fullering defined 53 
 
 Fulton, Robt ctitiv 
 
 Furnace, supply of air to 49 
 
INDEX. 215 
 
 Gas (coal) lbs. of water evaporated from and at 212* 50 
 
 Gas (coal) units of heat of combustion 60 
 
 Gas, first burns in combustion 48 
 
 Gas, ho w ignited 48 
 
 Generator, in ice making 146 
 
 Gland ; definition 76 
 
 Glass, specific gravity of 137 
 
 Globe valves ; to attach 84 
 
 Gold, specific gravity of 137 
 
 Government (U. 8.) rules tor examination of applicants for engi- 
 neers' licenses 186 
 
 Gauges, water 42 
 
 Grate bars 58 
 
 Gravity ; questions and answers relating to 134 
 
 Specific table.... 137 
 
 Gusset-stay 30 
 
 Gusset-stays, riveting of 34 
 
 Hammer-test of Kteam boilers 48 
 
 Hard coal, how to fire 43 
 
 Hard, or anthracite coal — total units of heat of combustion 50 
 
 Heads of boilers, dimensions 55 
 
 H ead-to-head brace 30 
 
 Beat and work 150 
 
 Cause of water circulation 46 
 
 Effect of, on strength of boilers 58 
 
 Effect on iron '. ,<. 21 
 
 Mechanical equivalent of 151 
 
 Of combustion, table of 50 
 
 Of saturated steam 101 
 
 Speci tic 153 
 
 The best non-conductor of 159 
 
 Transferable 15l 
 
 Unitof 154 
 
 Heating and ventilation 155 
 
 Heating surface of steam boilers, efficiency of 38 
 
 High and low pressure engines, difference 74 
 
 High and low pressure steam 62: 
 
 High pressure engines 64- 
 
 h omogeneous, definition 24- 
 
 Eorizontal tubular, advantages of 38 
 
 Horsepower; how to determine 79' 
 
 (H. P.) 138 
 
 Indicated and effective 125' 
 
 Necessary for given pressure 113- 
 
 Of steam boiler, rule 138 
 
 Shown by diagram 124 
 
 Hot-short iron or steel 24 
 
 Hotwater? Will pump lift 109' 
 
 Hydraulic test of steam boilers. 54 
 
 Hydrogen in steam 601 
 
 Total units of combustion ■ .. 60 
 
 Hydrometer; definition of — 138 
 
 Ice making, description 141 
 
 Imperfect insulation; effect of 131 
 
 indicated horse power (I. H. P.) • 138 
 
 Indicator card 121 
 
 How to measure easily 12S 
 
 Indicator diagram 123 
 
 General principles of 120 
 
 Questions and answers relating to 120 
 
 Initial pressure of steam , 63 
 
aiff HA-WKUfS" .4JD& 
 
 Injector or inspirator, defined < 117 
 
 Exhaust steam 119 
 
 Howtoconnect o 118 
 
 Injector; Modeof working J 119 
 
 And pump; difference between 117 
 
 Inspection of steam boilers ; laws relating to the 197 
 
 Sup't Parker's report 5J00 
 
 Insulation; definition of 131 
 
 Necessityof careful 130 
 
 Iron, defl.nition 35 
 
 Elongation of 24 
 
 Difference between, and steel 25 
 
 Hot-short and cold-short 24 
 
 Specific heatof ■, 153 
 
 Specific gravity of 137 
 
 Tensile strength of. 25 
 
 Jaw-brace . 80 
 
 Kinds of electricity 128 
 
 Knowledge (classification of) the key to success 17 
 
 Lap-joint, description , 56 
 
 Lap — why given a valve 72 
 
 Latent heat of steam 103 
 
 Lawof expansion of steam under pressure 61 
 
 Laws relating to the inspection of steam boilers 197 
 
 Laws relating to ventilation, air, etc 156 
 
 "Lead", how to set valve for — 71 
 
 Lead, specifio heat of 153 
 
 Specific gravity of 137 
 
 Leakage around boiler tubes, cause of..o 96 
 
 Leakypiston; totestfor 77 
 
 Pumps Ill 
 
 Slide valve; totestfor 77 
 
 Length of lever for valve to blow at given pressure 183 
 
 Lever; how to calculate power of 93-97 
 
 Kinds and classes of 93 
 
 Licensing of engineers; N. Y. City report 203 
 
 Brooklyn, N. Y., practice 
 
 License, necessary qualifications to secure — 13 
 
 Licenses granted, renewed and i-ejected (official report) ix 
 
 Lift of valves 115 
 
 Limit of lift to a pump 108 
 
 Live steam 59 
 
 Location of safety valve 90 
 
 Locomotive boilers, peculiarity of 40 
 
 Engines 65 
 
 Howtofire a 44 
 
 Loss in water for engine ; provision for 115 
 
 Low pressure steam 62 
 
 Low water: what is to be done in case of 42 
 
 Lugs; definition of 54 
 
 Magnet; electro 13 
 
 Permanent. • 13 
 
 Malleable metal 23 
 
 Marine boilers; peculiarity of 40 
 
 Engines 65 
 
 Marine engineers ; regulations relating to 186 
 
 Mean effective pressure; how to find 79 
 
 Table 80 
 
 Measures and weights 154 
 
 Mochaiucal equivalent of heat -^ 151 
 
 Rftfrigeratinn ,.f.... •••••. 1^ 
 
INDEX. ai7 
 
 Mercury ; specific gravity of 1S7 
 
 Specific heat of 153 
 
 aiullins, Washington ; sketcli of life 203 
 
 Multiplication of decimals 169 
 
 New steam plant ; first thing to be done in taking charge 158 
 
 Nominal horse power (N. H. P.) 138 
 
 Non-condensing engines 64 
 
 Non-conductors. 139 
 
 Non-conductor of heat ; the best 159 
 
 North pole of electro magnet 131 
 
 " North West " steamer, description of engines 81 
 
 Number of indicator spring 132 
 
 N. Y. City Laws, extract relating to qualifications 14 
 
 Report for 1893 ix 
 
 Bureau of boiler inspection 203 
 
 Oil, for lubrication of engine 78 
 
 Open air condenser defined ] 46 
 
 Ordinates ; how to measure easily 124 
 
 Overstraining of steam boilers 84 
 
 Oxygen in steam 60 
 
 Petroleum, lbs. of water evaporated from and at 312° 50 
 
 Units of heat of combustion 50 
 
 Physical properties of steam 59 
 
 Pipes, how to cure cracking and pounding 86 
 
 Fioe rule for approximate size 114 
 
 Covering ; importance of 158 
 
 Threads 87 
 
 Pfping of a mill or factory 156 
 
 Piping, first thing to be examined 158 
 
 Pitch line of rivet work 54 
 
 Planimeter ; description of 125 
 
 Plates of boilers ; thickness of 55 
 
 Points (4) shown by an Indicator 123 
 
 Poles of permanent or electro magnets 131 
 
 " Pop " safety valve ; definition of 90 
 
 Ports ; steam ; definition 76 
 
 Portable engines 65 
 
 Pressure allowed by inspectors 56 
 
 Initial, of steam 62 
 
 Mean effective, how to find 79 
 
 Terminal, of steam 63 
 
 Prevention of pmoke 160 
 
 Priming of steam boiler 140 
 
 Proportion ; rule of 170 
 
 Pumps ; description of different 105 
 
 Action of, described.. 106-107 
 
 Double and single acting 107 
 
 llow to set up and order 110 
 
 Pistona; area of 113 
 
 Steam and water ends of a 107 
 
 That leak Ill 
 
 Treatment of, in cold weather 110 
 
 Valves; size and lift 108,115 
 
 Questions and, answers relating to 107 
 
 Pump and injector ; difference between. 117 
 
 Pumping engines 112 
 
 Quadruple expansion engines 81 
 
 ualifications for boiler plates 24 
 
 Qualifications (3> necessary to secure engineer's license 13 
 
 Questions (elementary) by the examining engineer , 180 
 
 QueationfJ and answers relating to boiler braces and stays 8P 
 
218 HAWKINS' AIDS. 
 
 Questions and answers relating to Circulation of water in boilers 46 
 
 Combustion of coal 48 
 
 Construction and strength of 
 
 steam boilers 53 
 
 Electricity and electrie ma- 
 chines 127 
 
 Engine and boiler fittings 83 
 
 Expansion and contraction of 
 
 steam boilers 33 
 
 Firing 43 
 
 Gravity and strength of ma- 
 terials 134 
 
 Heat and work 151 
 
 Heating and ventilation 157 
 
 Incrustation and scale 35 
 
 Indicator 121 
 
 Materials for boilers 23 
 
 Physical properties of steam. 59 
 
 Pumps 107 
 
 Refrigeration 143 
 
 Safety valve 89 
 
 Smoke prevention 160 
 
 Steam Boiler 38 
 
 Steam engine 67 
 
 Steam injector 117 
 
 Reaumur thermometer, scale 153 
 
 Reducing valve 85 
 
 Refrigerant, defined 143 
 
 Refrigerate, defined 143 
 
 Refrigerating machine 143 
 
 Refrigeration ; questions and answers relating to 143 
 
 Direct and expansion systems 144 
 
 Regularity of speed 69 
 
 Regulations relating to marine engineers 186 
 
 Relief valve 84 
 
 Repairs to braces, how best made 33 
 
 Repellant property in steam . 63 
 
 Report of Chief Inspectors, New York and Brooklyn 200 
 
 Results obtained from diagram 123 
 
 Rivet holes ; pitch of 55 
 
 Location of 54 
 
 Riveting ; kinds of 53 
 
 Rivets, size used in joining sheets 53 
 
 Rotary engines 65 
 
 Rule for ascertaining number and size of stays needed 33 
 
 Calculating power of steam engine 79 
 
 Calculating strain on boiler stays 33 
 
 Capacity of boiler 116 
 
 Capacity of water cylinder 113 
 
 Estimating H. P. of steam boiler.. 140 
 
 Figuring safety valves 93-97 
 
 Finding water capacity of horizontal steam boiler 116 
 
 Finding capacity of pump per hour 113 
 
 Finding horse power necessary to pump water to a giv- 
 en height tl3 
 
 Finding the specific gravities of solids 136 
 
 Finding the total heat of steam 102 
 
 Finding water pumped in one minute 113 
 
 Reverse motion of a slide valve engine 75 
 
 Size of pipe for steam U.4 
 
 Rule of Proportion, and examples l7l 
 
 Three 170 
 
INDEX. 219 
 
 Rules for Firing 45 
 
 Setting up a steam pump 116 
 
 Size of safety valve 91 
 
 (U. S.) ; setting safety valves 183 
 
 Rusted spots in pipe ; how to treat — 86 
 
 Safety ; factor of, for fittings 86 
 
 Safety valve ; Government rules for the 183 
 
 Danger of sticking 89 
 
 Definition of a 89 
 
 Location and size 90 
 
 Safety valve Problems ; how to solve arithmetically 94 
 
 Rules for size of 91 
 
 Salinometer, defined 136 
 
 Salt, amount in sea-water 136 
 
 Sand ; specific gravity of 137 
 
 Saturated steam 59 
 
 Heatof 103 
 
 Table of properti iS of 98 99 
 
 Scale; different kinds of boiler 35 
 
 Scum-cock ; action of 36 
 
 Seam ; strength of riveted 56 
 
 Second assistant engineers 188 
 
 Setting a pump valve ; rules for 1-0 
 
 Shearing strength, definition of 23 
 
 Signs, arithmetical 165 
 
 Silver, specific gravity of 137 
 
 Single-acting engines 64 
 
 Single-acting pump 107 
 
 Single riveting 53 
 
 Slide valve, defined 1 ' 3 
 
 Duties of 73 
 
 Engine ; to reverse motion of 79 
 
 To test for leaks 77 
 
 Slippage 114 
 
 Smoke fThe), problem 160 
 
 Solid-brace 30 
 
 Soot, effect on the Interior of boilers 36 
 
 South pole of electro-magnet 131 
 
 Special report of N. Y. Bureau 203 
 
 Specific heat, definition and table 153 
 
 Specific gravity, table 137 
 
 Speed of escaping steam and water 118 
 
 Speed ; regularity of , 70 
 
 Spring ; number of an indicator 133 
 
 Standard of cold production 143 
 
 Starting an engine 78 
 
 Stationary boilers ; kinds of 38 
 
 Engines 65 
 
 Stays ; boiler 190 
 
 Riveting of gusset stays 34 
 
 Steam. ; Boilers, description 21 
 
 Boiler ; horizontal tubular 38 
 
 " Breathing " of 34 
 
 Cause of explosion 41 
 
 F.ffect of heat on strength of 58 
 
 Fixtures ; list of 83 
 
 Fulcring 53 
 
 Horse power of ; rule 140 
 
 How to calculate strength of, with, example 57 
 
 flow to calculate the force of expansion and con- 
 traction -•• 38 
 
220 HAWKINS' AIDS. 
 
 Steam Boiler; How to prepare for inspection 198 
 
 Inspection ; N. Y. City report 203 
 
 Inspection ; Brooklyn, N. Y., report 200 
 
 Laws relating to the inspection of 197 
 
 Locomotive 40 
 
 Marine 40 
 
 Method of testing 54 
 
 Overstraining of 34 
 
 Principal kinds 38 
 
 Questions and answers relating to 53 
 
 Stationary 88 
 
 To calculate strength of seam 56 
 
 Tube plate of 55 
 
 Water tube 39 
 
 Steam ; absolute pi essure of 63 
 
 Dead 59 
 
 Dry 59 
 
 Dry ; as a conductor 104 
 
 Expansion under pressure 60 
 
 Gain in expansion 104 
 
 Heating ; Questions and answers relating to 157 
 
 Heating and ventilation 155 
 
 How to generate, at 212° F 102 
 
 Invisibility of 50 
 
 Live 59 
 
 Of what formed 121 
 
 Physical properties of 59 
 
 Repellant quality of particles of 63 
 
 Saturated 59 
 
 Saturated ; Tables 98-99 
 
 Superheated 61 
 
 Total heat of 103 
 
 "Weight of .0 61 
 
 Wet 63 
 
 Wire drawing of 63 
 
 Steam-end of a pump 107 
 
 Engine 64 
 
 Engines ; questions and answers 67 
 
 Generators, principal kinds 38 
 
 Injectors ; questions and answers relating to 117 
 
 Jacket 104 
 
 Line 131 
 
 Pipe covering ; importance of 158 
 
 Pipe ; how to estimate the safe working pressure 86 
 
 Pipe ; tensile strength of 87 
 
 Pipe ; how to estimate the diameter of 86 
 
 Pipe ; how to estimate the size of 114 
 
 Pipe ; Threads of 87 
 
 Pumps ; direct acting Ill 
 
 Valves ; how to connect 86 
 
 Steamer " Northwest," description of engines 81 
 
 Steel, definition 25 
 
 Difference between, and iron 25 
 
 Specific heat of - , 153 
 
 Specific gravity of 137 
 
 Tensile strength of 25 
 
 Strain and stress defined 135 
 
 Strength of riveted seam 56 
 
 Steam boilers 53 
 
 Stress and strain defined 135 
 
 Stress carried by boiler stays, example 33 
 
INDEX. 221 
 
 Stuffing-box, definition 76 
 
 Submerged condenser, defined 146 
 
 Subtraction of decimals 168 
 
 Suction chamber 110 
 
 Suction lift of a pump 108 
 
 Suction pipes, what they should be provided with , ill 
 
 Sulphur ; specific gravity of 137 
 
 Summary of arithmetic ... 166 
 
 Switch ; definition of a , 132 
 
 Table of heat of combustion 50 
 
 Mean pressures when cutting off 80 
 
 Number of indicator spring 123 
 
 Properties of saturated steam 98-99 
 
 Specific heat 153 
 
 Specific gravities 137 
 
 Taking charge of anew engine 88 
 
 Tensile strength defi ned 135 
 
 Testing boilers ; method of 54 
 
 Thermometer ; Centigrade, description 152 
 
 Description 152 
 
 Fahrenheit's 152 
 
 Thimbles for boilers 83 
 
 Third assistant engineers 189 
 
 Three ; Rule of 170 
 
 Three-way cock 85 
 
 Throttle valve 85 
 
 Throttling engines 68 
 
 Through braces .30 
 
 Time ; unit of. 154 
 
 Tin, specific gravity 137 
 
 Tortional strength 135 
 
 Total heat of steam 102 
 
 " Tough " metal 23 
 
 Transverse strength defined 135 
 
 Triple expansion engines 81 
 
 Tube plate, defined 55 
 
 T. U. (thermal unit) 108 
 
 Unit of arithmetical calculations 154 
 
 Heat 151,154 
 
 Pressure 154 
 
 Time 154 
 
 Work 154 
 
 U. S. Government rules for the safety valve 182 
 
 Vacuum 73 
 
 Valve ; definition of a . , 84, 108 
 
 Valves of Corliss engines ; how to set 174 
 
 Valve ; relief, back pressure, ball, three-way, cock, check, throt- 
 tle, reducing, etc 85 
 
 Valve spindle 90 
 
 Ventilation ; heating and 155 
 
 Latest idea relating to 159 
 
 Questions and answers relating to 157 
 
 Water and steam, as shown by diagram 124 
 
 Cohesion of 63 
 
 Composition of 116 
 
 Circulation in boilers 47 
 
 Cvlinder ; capacity of 113 
 
 End of a pump 107 
 
 Gauges 42 
 
 la the cylinder ; effect of 74 
 
 Specific heat of 153 
 
323 USTDEX. 
 
 Water Standard for specific gravity 134 
 
 Tube boilers, good and bad points 39 
 
 Weakness in boilers ; cause of 41 
 
 Weight for given safety valve to blow at given pressure 183 
 
 Weight ; relative, of steam, water and air 61 
 
 Weights ; measures and 154 
 
 Weldable metal 23 
 
 Wet steam =. 63 
 
 Wiredrawing • 63 
 
 Wood, lbs. of water evaporated from and at 212° 50 
 
 Units of heat of combustion 50 
 
 Work ; beat and 150 
 
 Unit of 154 
 
 Units of, as units of heat. ..... 1^^ 
 
LIST. 
 
 !. 
 Hawkins' New Catechism of Electricity, price post-paid, $2.00 
 
 II. 
 Hawkins' Aids to Engineers' Examinations, price post- 
 paid, . 2.00 
 
 (with Questions and Answers.) 
 111. 
 
 Hawkins' Maxims and Instructions for the Boiler Room, 
 
 price post-paid, - - - - - - 2.00 
 
 IV. 
 Hawkins' Hand Book of Calculations for Engineers, price 
 
 post-paid, - - - - - - - 2.00 
 
 V. 
 Hawkins' New Catechism of the Steam Engine, price 
 
 post-paid, - 2.C0 
 
 VI. 
 
 Hawkins' Indicator Catechism (a practical treatise), price 
 
 post-paid, ....... \QQ 
 
 Each volume is provided with a carefully arranged refer- 
 ence index, which places at ready commaud the information 
 contained in the book upon any special subject upon which 
 immediate help is needed. 
 
New 
 Catechism 
 
 of 
 Electricity. 
 
 A 
 
 Practical 
 
 Treatise 
 
 Price, $2. 
 
 This volume contains 550 pages of valuable informa- 
 tion, 300 diagrams and illustrations, handsomely 
 bound in heavy red leather, with gold edges, making 
 a handy pocket companion, replete with invaluable 
 knowledge; size 41^ x 6]/^ inches. 
 
 This book has been issued in response to a real 
 demand for a plain and practical treatise on the care 
 and management of electrical plants and apparatus — 
 a book to aid the average man, rather than the invent- 
 or or experimenter in this all-alive matter. 
 
 Hence the work will be found to be most complete 
 ia this particular direction, containing all the. (book) 
 information necessary for an experienced man to take 
 charge of a dynamo or plant of any size. 
 
 So important is the subject matter of this admirable 
 work that there is only one time to order it and that is 
 N0\\ . 
 
CONTENTS. 
 
 The Dynamo; Conductors and Non-Conductors ; 
 Symbols, abbreviations and definitions relating to 
 electricity; Parts of the Dynamo; The Motor; The 
 Care and Management of the Dynamo and Motor. 
 
 Electric Lighting; Wiring; The rules and require- 
 ments of the National Board of Underwriters in full; 
 Electrical Measurements. 
 
 The Electric Railway; Line Work; Instruction and 
 Cautions for Linemen and the Dynamo Room ; Storage 
 Batteries; Care and Management of tlie Street Car 
 Motor; Electro Plating. 
 
 The Telephone and Telegraph; The Electric Eleva- 
 tor; Accidents and Emergencies, etc., etc. 
 
 The full one-third part of the whole work has been 
 devoted to the explanation and illustrations of the 
 dynamo, and particular directions relating to its care 
 and management; — all the directions are given in the 
 simplest and most kindly way to assist rather than 
 confuse the learner. The names of the various parts 
 of the machine are also given with pictorial illustra- 
 tions of the same. 
 
 In the Catechism no less than 25 full page illustra- 
 tions have been given of the various dynamo machines 
 made in different parts of the country, and an equal 
 number of part page illustrations. 
 
Questions 
 
 s 
 
 Engineers. 
 
 This volume has over 2do pages of practical "pointers" 
 showing the path of advancement, so much desired by aspiring 
 engineers and firemen. It is printed on excellent paper and 
 handsomely bound in heavy red leather, with gold title and 
 edges. It is strongly bound for continuous study ; the size is 
 5 X ■]%.. 
 
 The work is a most important aid to all engineers, and 
 is undoubtedly the most helpful ever issued relating to a safe 
 and sure preparation for examination. 
 
 It presents in a condensed form the most approved prac- 
 tice in the care and management of Steam Boilers, Engines, 
 Pumps, Electrical and Refrigerating Machines. 
 
 On the following page is a list of its "helpful" contents. 
 
CONTENTvS 
 
 This book embraces information not elsewhere obtainable. 
 
 It tells exactly what an engineer will have to go through 
 in getting a license, with much kindly and helpful advice to 
 the applicant for a license. 
 
 It contains the annual report of the superintendents of 
 "Steam Boiler Inspection and Certification of Engineers" for 
 the cities of New York and Brooklyn. 
 
 It contains various rules, regulations and laws of cities 
 for the examination of boilers and the licensing of engineers. 
 
 It contains the laws and regulations of the United States 
 for the examination and grading of all marine engineers. 
 
 It gives a short chapter on the "Key to Success" in 
 obtaining knowledge necessary for advancement in engineering. 
 This is very important. 
 
 The book gives the underlying principles of steam engineer- 
 ing in plain language, with sample questions and answers 
 likely to be asked by the examiner. 
 
 It gives a few plain rules of arithmetic with examples of 
 how to work the problems relating to the safety valve, strength 
 of boilers and horse power of the Steam Engine and Steam 
 Boiler. 
 
 The main subjects treated, upon which are given detailed 
 information with questions and answers, are as follows: — 
 The Steam Boiler, Boiler Braces, Incrustation and Scale, 
 Firing of Steam Boilers, "Water Circulation in Boilers, Con- 
 struction and Strength of Boilers, The Steam Engine, Engine 
 and Boiler Fittings, Pumps, The Injector, Electricity and 
 Electric Machines, Steam Heating, Refrigeration, Valve 
 Setting, etc. , etc. 
 
Maxims 
 
 and 
 
 Instructions 
 
 for the 
 
 Boiler Room 
 
 Price, $2. 
 
 This is, of all the Hawkins books, perhaps the 
 most useful to the Engineer-in-charge, to the Fireman, 
 to the Steam user or owner, and to the student of 
 Steam Engineering. 
 
 It is uniform in binding and size with ** Calcula- 
 tions for Engineers " and the "New Catechism of the 
 Steam Engine"; the size is 6xS}( inches, i}( inches 
 thick; weight 2 lbs. ; it is bound in green silk cloth, 
 gilt top and titles in gold; it has 331 pages with 185 
 diagrams and illustrations. 
 
 See next page for further particulars relating to 
 the practical subjects embraced in this valuable 
 
 volume. 
 
conte:nt^ 
 
 Materials; Evaporation; Fire Irons and Tools; 
 Firing of Steam Boilers; Points relating to Fuels; 
 Foaming; Chapter of Don'ts ; Full descriptions of the 
 Locomotive, Upright, Water Tube, Horizontal, and 
 Marine Steam Boilers, Parts of a Boiler; Various 
 Specifications for Construction of a Boiler; Riveting; 
 Bracing; Various Repairs; Grate Bars; Boiler 
 Cleaners; Boiler Scales; Boiler Tests; Scumming; 
 Chemical Terms; Inspection of Boilers; Mechanical 
 Stokers; Pumping Machinery ; Feed Water Heaters; 
 Steam Heating; Plumbing; Safety Valve Rules. 
 
 And many hundreds of other valuable pointers 
 for Steam Users, Superintendents, Engineers, etc. 
 
 No Engineer, Fireman or Steam User can afford 
 to be without this valuable book, as it contains tht, 
 pith and vital " points " of economical and safe steam 
 production. 
 
 The plan followed in this work is the same as 
 that so generally approved in "Calculations"; it 
 proceeds from the most simple rules and maxims to 
 the highest problems; it is both a book of instruction 
 and reference. The carefully prepared Index con- 
 tains nearly one thousand references, thus making it 
 almost a dictionary of terms. 
 

 Engineers. 
 Price $2. 
 
 The work comprises the elements of Arithmetic, Mensura- 
 tion, Geometr}', Mechanical Philosophy, with copious notes, 
 explanations and help rules useful to an Engineer. 
 
 And for reference, tables of squares and cubes, square and 
 cube roots, circumference and areas of circles, tables of weights 
 of metals and pipes, tables of pressures of steam, etc., etc. 
 
 This is a work of instruction and reference relating to the 
 steam engine, the steam boiler, etc , and has been said to con- 
 tain every calculation, rule and table necessary to be known by 
 the Engineer, Fireman and steam user. 
 
 It is thus a complete course in Mathematics for the Engineer 
 and steam user ; all calculations are in plain arithmetical 
 figures, so the average man need not be confused by the inser- 
 tion of the terms, symbols and characters to be found in works 
 of " higher mathematics," so-called, yet the book is a complete 
 treatise. 
 
 It is bound uniform with the " New Catechism of the Steam 
 Engine" and the "Instructions for the Boiler Room" (size 
 6 X S3/( inches, weight 2 lbs. ) ; in green silk cloth ; printed on 
 heavy, fine surface paper ; gold titles, gilt top ; with 330 pages 
 and 150 illustrations. 
 
CONTENTS. 
 
 Mechanical Powers; Natural or Mechanical Philos- 
 ophy; Strength of Materials; Mensuration; Arith- 
 metic ; Description of Algebra and Geometry ; Tables 
 of Weights, Measures, Strength of Rope and Chains, 
 Pressures of Water, Diameter of Pipes, etc. ; The 
 Indicator, How to Compute; The Safety Valve, How 
 to Figure; The Steam Boiler; The Steam Pump; 
 Horse Powers, How to Figure for Engines and 
 Boilers; Steam. What It Is, etc.; Index and Useful 
 Definitions. 
 
 " I am pleased with the work ; it is of 
 value to nie. I have charge of a Harris- 
 Corliss engine doing 680 H. P. at Slater's 
 Cotton Mills."— Cyrus Bucki<in, Paw- 
 tucket, R. I. 
 
 "I think it the best T ever saw, and I 
 thank the day I saw it advertised." — 
 Jno. C. Robinson, Adams, Mass. 
 
 "The Hand Book is worth its weight in 
 dollars to any engineer with common 
 sense."— J AS. C. Temple, Eng., Spring- 
 field, 111. 
 
NEW 
 CATECHISM 
 
 OF THE : 
 STEAMENGIi 
 
 New 
 Catechism 
 
 of the 
 
 Steam 
 Engine. 
 
 Price, $2. 
 
 This is a rarely fine book, handsomely bound, in 
 green silk cloth, gilt top, titles in gold; 440 pages; 
 325 illustrations; size 6x8^ inches, i}( inches thick; 
 weight 2 lbs. It is bound uniform in style and size.; 
 with the "Hand Book of Calculations" and "Maxims 
 and Instructions for the Boiler Room. " 
 
 This will prove a valuable book both for study and 
 reference, being finely illustrated and indexed. 
 
 This work is gotten up to fill a long-felt need for a 
 practical book. It gives directions for running the 
 various types of steam engines that are to-day in the 
 market. A list of subjects which are fully yet con- 
 cisely discussed are found on the next page. 
 
CONTENTvS. 
 
 The subject matter of the New Catechism of the 
 Steam Engine is not arranged in chapters, but accord 
 ing to the more natural order best designed to explain 
 at greater or less length the different themes discussed. 
 The following are the leading divisions of the 480 
 pages of the book: 
 
 Introduction; The Steam Engine; Historical Facts 
 Relating to the Steam Engine; Engine Foundations; 
 The Steam Piston; Connecting Rods; Eccentric; 
 Governor ; Materials ; Workmanship ; Care and 
 Management; Lining up a Horizontal or Vertical 
 Engine; Lining Shafting; Valve Setting; Condensers ; 
 Steam Separators ; Air, Gas and Compressing Engines ; 
 Compounding; Arithmetic of the Steam Engine; 
 Theory of the Steam Engine; Construction. 
 
 There is also a description of numerous types of 
 the engines now in operation, such as the Corliss, 
 Westinghouse, etc. 
 
 The book also treats generously upon the Marine, 
 Locomotive and Gas Engines. 
 
Indicator 
 Catechism 
 
 Price, $1. 
 
 This is a new book on an important subject. It is designed 
 to thoroughly instruct the buyer upon the practical use of the 
 Indicator, the Planimeter, the Pantagraph, Reducing Motions, 
 etc. It contains nearly 200 pages with 1 15 valuable illustrations 
 and diagrams, with questions and answers. 
 
 CONTENTS.— Preparing Indicator for Use; Reducing 
 Motions ; Piping up Indicator ; Taking Indicator Cards ; The 
 Diagram ; Figuring Steam Consumption by the Diagram ; 
 Revolution Counters ; Examples of Diagrams ; Description 
 of Indicators ; Measuring Diagram by Ordinates ; Planimeters ; 
 Pantagraphs, Tables, etc. 
 
 The book is handsomely bound in silk (red) cloth, gilt edges, 
 gold titles ; it is 5)4 x S){ inches and weighs 1}^ lbs. 
 
EASY PAYMENT OFFER. 
 
 The Hawkins' Works are sold on easy payments; 
 the set, six volames, price $i i.oo, will be sent express 
 prepaid to any address upon receipt of $i.oo, and 
 agreement to pay balance in monthly installments of 
 |!i.oo Each volume is complete in itself; one, two 
 three, four or five books of the series will be sent on 
 the easy terms, that is one dollar with order and the 
 remainder of the purchase money $i.oo monthly. 
 
 HCW TO OF.DER. 
 
 With this pamphlet is sent a blank form ready for 
 signing, and a return envelope; these are for con- 
 venience, and not necessary to be used, as a simple 
 order enclosing $i.oo and an agreement to send 
 balance, $i.oo per month, will be sufficient. 
 
 PUBI^ISHEI^S' GUARANTEE. 
 
 The Publishers agree that if the books are not all 
 that they are claimed to be, they can be returned and 
 the money paid will be returned to the purchaser. 
 
 PERSONAL STATEMENT. 
 
 In ordering it is kindly requested that our patrons 
 send one or two names of whom inquiry can be made, 
 if desired — the question being — "Is the party good 
 for what he agrees?" But! a simple statement as to 
 position held will be sufficient. 
 
<o^ 
 
 
 ^ Directions.'^ 
 
 All books are shipped to subscribers, post or express 
 charges paid, upon receipt of order. 
 
 Remittances can be sent by Post Office or Express 
 Money Orders, payable to our order. 
 
 ^