r 
 
 REESE LIBRARY 
 
 UNIVERSITY OF CALIFORNIA. 
 
 > 
 
 ~R^nl^ .i&>&. 
 
 / 
 
 No. yb 6 3(o Class No. 
 
 CATALOGUES FKEE. 
 
 LANCASTER & TONCE, 
 
 ENGINEERS AND BRASSFOUNDERS, 
 PENDLETON, MANCHESTER. 
 
A D VEK T I SEME NT* 
 
 Of all the modern appliances for reducing the cost of steam raising, 
 none exceeds in importance the " MELDRUM " FORCED 
 DRAUGHT FURNACE, as by its use the cheaper fuels are 
 made to do the duty formerly requiring best coal to perform. 
 
 Over \J working. Effecting, in some cases, an 
 
 economy of i^\J PER CENT* 
 
 Adopted by most of the largest steam users in the country. 
 No tall chimney required. 
 Defective draught readily overcome. 
 Efficiency of existing boilers largely increased. 
 
 Write for Illustrated Catalogue. 
 
 MELDRUM BROTHERS, 
 
 ATLANTIC WORKS, 
 CITY ROAD, 
 
 MANCHESTER. 
 
 Also at LONDON and LEEDS. 
 
 Telegrams "MELDRUM," Manchester, London, or Leeds. 
 
Demy 8vo, doth, 330 pp. 108 Illustrations. 5s. 
 
 STEAM LOCOMOTION 
 
 ON COMMON BOADS. 
 
 BY 
 W. FLETCHER 
 
 OPINIONS OF THE PRESS. 
 
 *< The Engineer." " A book written by a practical engineer, and 
 an expert in the subject he deals with." 
 
 "Industries." "Notes on the design and construction of road 
 locomotives will be found most useful. Mr. Fletcher's book forms a 
 valuable addition to the engineer's library." 
 
 " The Mechanical World." " Mr. Fletcher has had considerable 
 experience of a kind that eminently fits him for the task he has 
 undertaken." 
 
 " The Practical Engineer." " It forms a chapter in the history 
 of the steam engine which no student should omit to read." 
 
 "The English Mechanic." "Mr. Fletcher's book will be wel- 
 come. All who are interested in the subject should procure this, 
 work." 
 
 'British Trade Journal." " Profusely illustrated with many 
 original drawings." 
 
 "Engineering News and American Railway Journal." 
 
 " It is a valuable addition to engineering literature on a subject hereto- 
 fore scattered through all manner of obscure and practically inacces- 
 sible books and publications." 
 
 "The Scientific American." "This work contains an amount 
 
 of interesting matter of peculiar value at this day." 
 
 "The Indian Engineer." "Mr. Fletcher's very interesting and 
 extremely well-written bock is illustrated in the best style." 
 
 " The Machinery Market."" The only book on this attractive 
 and popular subject." 
 
 " Colliery Guardian." "Our readers will find this a fascinating 
 work, and the only one extant on this important subject." 
 
 " The Implement Review."" A valuable and exhaustive treatise 
 which ought to be in the hands of everybody associated with the im- 
 portant industry it so faithfully details." 
 
 "The Ipswich Journal." "It must represent many years of 
 study and research, and is an example of what may be accomplished 
 by industry, ability, and patience." 
 
 LONDON : E. & F. N. SPON, 125 STRAND. 
 NEW YOKK : SPON & CHAMBERLAIN, 12 CONTLANDT ST. 
 
Tie ABUSE of the STEAM JACKET 
 
 PRACTICALLY CONSIDERED. 
 
 BY 
 
 W. FLETCHER 
 OPINIONS OF THE PRESS. 
 
 41 The Mechanical World" says : " As a treatise on steam 
 jacketing Mr. Fletcher's little book is most excellent, and may, with 
 confidence, be recommended as a safe guide on an important subject." 
 
 " The English Mechanic " says: " In this useful and practical 
 manual many defects in construction are clearly pointed out by Mr. 
 Fletcher, who gives diagrams showing how the steam jacket should be 
 arranged ; and those who are interested in the subject would do well 
 to read what he has to say in the work. " 
 
 "British Trade Journal" says: "The conflicting opinions 
 which prevail respecting the utility of the steam jacket have led Mr. 
 Fletcher to make an attempt to put users of steam right upon the 
 subject. He has evidently given the subject a thorough consideration, 
 and practical engineers will peruse his treatise with profit." 
 
 " Iron " says : " In the above work many useful suggestions, the 
 result of careful observation, are set forth ; the publication has much 
 to recommend it." 
 
 " Colliery Guardian " says : " The author gives some valuable 
 introductory remarks, after which he points out the defects in many 
 steam jackets now in use, and lays down some principles relating to 
 their proper design and application. The book is worth reading, as 
 developing the practical views of an engineer who has evidently well 
 considered the subject." 
 
 " The Implement Review" says : " Mr. Fletcher has written 
 a book which should prove, and we trust it may, of some service to 
 the designers and makers of steam engines. It is the fullest treatise 
 upon the steam jacket that has yet appeared ; it should be in the 
 possession of every mechanical engineer." 
 
 *' Machinery Market" says : " The subject has been well con- 
 sidered by Mr. Fletcher, and his method of dealing with it affords 
 material which should prove useful to engineers generally." 
 
 ' Hants and Berks Gazette " says:" Mr. Fletcher has chosen a 
 subject on which a great amount of ignorance prevails in the engineer- 
 ing community, and this contribution to their technical literature will 
 be hailed with pleasure." 
 
Crown 8vo, 21s. 
 
 Steam Power and Mill Work : Modem Practice in. With 
 
 numerous Tables, Illustrations, &c. By G. W. SUTCLIFFE, M.Inst. C.E. 
 (Whitworth Scholar). 
 
 CONTENTS : Heat and Work Fuel and Combustion Calorimeters Storage 
 and Manipulation of Coal Coal Washing for the Removal of Solid Waste- 
 Connection, Circulation, Evaporation, and Priming in Boilers Forced Draft 
 Gas Firing Use of Liquid Fuel Analysis of Gases produced in Combustion 
 Water for Use in Boilers Boilers Boiler Houses and Boiler Setting Chimneys 
 Economisers Crossheads and Connecting Rods Crank Shafts Gearing, <tec., 
 &c. 
 
 By the late Sir GEORGE FINDLAY, Assoc. Inst. C.E., General Manager 
 of the London and North- Western Railway. 
 
 An English Railway, The Working- and Management 
 
 of. Fifth Edition, thoroughly revised and enlarged, with a short Biography 
 of Sir George Findlay, and Portrait, Appendix and numerous Illustrations. 
 Crown 8vo, cloth, 7s. 6d. 
 
 "This is a delightful book." Engineer. "Mr Findlay's book displays so 
 much knowledge and ability that it well deserves to rank as a standard work 
 on the subject." Nature. "A very interesting work throughout." Railway 
 Engineer. " Mr Findlay's book will take a high position in the library of 
 practical science." Athcnceum. 
 
 By C. J. BOWEN COOKE, Assistant, London and North- Western 
 Locomotive Department. 
 
 British Locomotives. Their History, Construction, 
 
 and Modern Development. With 150 Illustrations. Second Edition, 
 
 revised. Crown Svo. 7s. 6d. 
 
 "An excellent work . . . Every driver and fireman should possess a 
 copy." Engineer. '-We congratulate the author on having produced a book 
 which will be deservedly successful." Railway Engineer. "This new work 
 constitutes undoubtedly a most valuable addition to railway literature. "-- 
 Railway Herald. "A very attractive and instructive little work." Times, 
 October 5th, 1893. " A most interesting book." Nature. 
 
 Works by a FOREMAN PATTERN MAKER. 
 
 Practical Iron Founding. Illustrated with over 100 En- 
 gravings. Second Edition. 4s. 
 
 "Every pupil and apprentice would find it, we think, an assistance to 
 obtaining a thorough knowledge of his work. The book, however, is not 
 intended merely for the student, but contains much useful information for 
 practical men." Industries. 
 
 The Principles Of Fitting. For Engineer Students. Illustrated 
 with 250 Engravings, and containing an Appendix of Useful Shop Notes 
 and Memoranda. Crown Svo. 5s. 
 
 ' ' A practical manual for practical people. "English Mechanic. '^ Calculated 
 to aid and encourage the most useful set of handicraftsmen we have amongst 
 us." Daily Chronicle. 
 
 The Principles of Pattern Making. Written specially for 
 
 Apprentices and for Students in Technical Schools. Illustrated with 101 
 Engravings, and containing a Glossary of the Common Terms employed in 
 Pattern Making and Moulding. 3s. 6d. 
 " We have no hesitation in recommending the book to technical students 
 
 and apprentices." Mechanical World. " This is one of those works which 
 
 have more than ordinary value." Steamship. 
 
 LONDON: WHITTAKER & CO., PATERNOSTER SQUARE. 
 
THE STEAM JACKET 
 
 PRACTICALLY CONSIDERED 
 
GREEN'S 
 ECONOMISED 
 
 THE 
 
 STANDARD FEED WATER HEATER 
 
 FOR 
 
 STEAM BOILERS. 
 
 OF 
 
 157. 
 
 EFFECTS 
 
 A 
 SAVING 25 
 
 By utilising the 'Waste Flue Cases. 
 
 TO 
 
 IN 
 COAL 
 
 ORIGINAL INVENTORS AND SOLE MAKERS: 
 
 E, GREEN & SON, LIMITED, 
 
 EXOHA1NOE STREET, 
 
 MANCHESTER. 
 
THE STEAM JACKET 
 
 PRACTICALLY CONSIDERED AS AN EFFICIENT FUEL ECONOMISER, 
 
 A TREATISE ON THE 
 
 ECONOMICAL USE OF STEAM FOR ENGINE-BUILDERS, 
 
 ENGINE-DRIVERS, MILL-MANAGERS, AND 
 
 S TEA M- USERS GENERALL Y. 
 
 BY 
 
 WILLIAM FLETCHER, 
 
 AUTHOR OF 
 THK HISTORY AND DEVELOPMENT OK STEAM LOCOMOTION ON COMMON ROADS. 
 
 WITH SIXTY-THREE ILLUSTRATIONS. 
 
 (Bbltioit, HUbiscJr mtb ^nlargtb. /^P- E 
 
 f UNIVERSITY 
 
 LONDON : WHITTAKER AND CO., 
 
 2 WHITE HART STREET, PATERNOSTER SQUARE-, LONDON 
 AND 66 FIFTH AVENUE, NEW YORK. 
 
 1 895- 
 
 [All rights reser-veci.\ 
 
PRINTED BY NEILL AND COMPANY, EDINBURGH. 
 
PREFACE TO THE FIRST EDITION. 
 
 THE origin of this little book may soon be told. Some 
 years ago, the author purposed writing a letter to one 
 of the engineering journals on the Steam- Jacket, in 
 reply to a correspondent who sought information on 
 the subject. A large amount of matter was collected, 
 but, owing to the time devoe4 ..to the search, he was 
 led to relinquish the idea of the letter. But he 
 continued the study, with a view, at some distant 
 date, of writing a book on the steam-jacket. When 
 busily engaged with this work, it was found that little 
 or nothing had been said about the misapplication of 
 the steam-jacket ; while experience showed that a 
 large number of the so-called steam-jackets were 
 steam-jackets in name only. The utility of four out 
 of every six jackets that were examined must have 
 been impaired by imperfections. In the present 
 treatise the author has shown the defects in many 
 steam-jacketed cylinders, and also given some of the 
 principles relating to their proper design and applica^ 
 tion. As this book furnishes the only information on 
 this neglected subject, he trusts that the contents may 
 prove of some service to designers and makers of 
 steam-engines. Mention may be made here that the 
 scarcity of engineering books written by practical 
 
 b 
 
vi PREFACE TO THE FIRST EDITION 
 
 men,* has* served as an incentive to energy, hoping 
 that this first literary venture, emanating from the 
 drawing-office and works, may meet with some measure 
 of support and approval. 
 
 Our cleverest engineers, and those- most competent 
 to write good practical books which would be of 
 permanent value to the rising generation of engineers, 
 are so busily engaged in the manufacture of engines, 
 that they have not the time to write about them, for 
 the very reason that the manufacture of engines is a 
 far more profitable undertaking than the production 
 of books relating to engines. 
 
 In many engineering books, the efforts of the 
 authors are spread over such a large surface that the 
 information given is too superficial to be of any real 
 value : where a few lines are devoted to the explana- 
 tion of each detail of the steam-engine for instance, in 
 all probability those few lines fail to supply the 
 information needed, and serve no good purpose to the 
 inquiring mind. Who does not remember reading 
 numerous books of this class in the hope of finding 
 some valuable notes, and, after wading through the 
 contents, have had to close them in disappoint- 
 ment ? 
 
 Take, for illustration, the valuable detail we are 
 studying the steam-jacket. In many works on the 
 steam-engine it is not even mentioned ; in some, two 
 or three paragraphs only are devoted to its considera- 
 tion ; and those few who have written more lengthily 
 have treated it, like many more engineering subjects, 
 in a theoretical style, so that the literature is adapted 
 for students only, and is perfectly useless in the 
 
 * "Well written, practical books, from the pens of competent practical 
 men, are as scarce and nearly as valuable as gold." The Engineer, 17th 
 May 1872. 
 
PREFACE TO THE FIRST EDITION vii 
 
 workshop, and, in the majority of cases, of very little 
 real service in the drawing-office. 
 
 If authors would confine themselves to the study of 
 one detail, and thoroughly ventilate it, their remarks 
 could not fail to be of practical service ; indeed, this 
 is just the style of book relating to the steam-engine of 
 which there is the greatest need. 
 
 It may be owing to this dearth of literature, in 
 a great measure, that accounts for such widespread 
 ignorance respecting the use of the steam-jacket 
 prevailing among engineers. It is to many a perplex- 
 ing paradox. When engine-makers, who do not apply 
 it, evidence some hazy notions respecting its utility, 
 there is no occasion for surprise. But, when we find 
 engineers at the head of one of the largest portable 
 engine firms (who profess to have jacketed their 
 earliest engines, and still continue the practice) saying 
 that the cylinder is protected from " cold and radia- 
 tion " by 'means of a jacket of steam, clearly showing 
 that the function of the steam-jacket is not understood 
 by the writers, it does cause some astonishment. 
 They can be excused on the ground above named, viz., 
 the fragmentary nature of the information relating to 
 this subject. One writer says : " Almost every 
 engineer knows now-a-days that a cylinder should be 
 kept as hot as possible ; but very few makers of 
 steam-engines understand the precise reasons why a 
 cylinder should be kept hot. Most people imagine 
 that the condensation takes place by conduction 
 through the metal of the cylinder to the outside." 
 
 We have related at page 71 an instance wherein an 
 engine-maker thought a steam-jacket was not required, 
 because the cylinders were well lagged and felt com- 
 paratively cool on the surface. 
 
 As a consequence of the prevalence of these 
 
viii PREFACE TO THE FIRST EDITION 
 
 mistaken notions, it follows that very little, if any, 
 good has resulted from the voluminous discussions on 
 steam-jacketing. The practical conclusion of the 
 whole matter appears to be : The fact of the utility 
 of the steam-jacket, when properly applied, cannot be 
 gainsaid, but, owing to numerous cases of internal 
 mal-arrangement, its efficiency is impaired or destroyed, 
 occasioning in some quarters a doubt respecting its 
 advantage. 
 
 W. FLETCHER 
 
 BASINGSTOKE. 
 
PREFACE TO THE SECOND EDITION. 
 
 THE first edition of The Abuse of the Steam-Jacket 
 Practically Considered, is exhausted. It is believed that 
 a second edition of the work is required. The first 
 edition was not only favourably reviewed by many of 
 the technical journals, but the author received some 
 friendly letters from (previously unknown) correspon- 
 dents, thanking him for the work, and acknowledging 
 the service rendered by it to designers of steam- 
 engines particularly. The Electrical Review, in com- 
 menting on one of the author's articles on this subject, 
 said : " Mr. Fletcher has been discussing jackets for 
 many years, and there is still very good cause to 
 continue the discussion. It is much to be feared that 
 numerous learned disquisitions have appeared on the 
 behaviour of steam in the cylinder, which have been 
 argued out with a great array of mathematics from 
 results whose true meaning has been entirely obscured 
 by faulty construction. Papers like this of Mr. 
 Fletcher's might well be kept in type, and used at 
 periodical intervals, as corrective of that depravity of 
 design which lends so much force to the arguments in 
 favour of the totality of the specially human failing 
 to go wrong where it is as easy to go right." * It is 
 gratifying also to know that a perusal of the little 
 book led to a set of standard engine cylinder patterns 
 * The Electrical Review, 2nd June 1893. 
 
x PREFACE TO THE SECOND EDITION 
 
 being modified in design, so as to accord with the 
 requirements of efficient steam-jacketing. In issuing 
 the second edition, the scope of the work has been 
 extended, and it now forms a complete treatise on 
 steam-jacketing. All the matter of value contained 
 in the first edition has been retained, and the informa- 
 tion brought down to date. 
 
 The abuse of the steam-jacket occupies a prominent 
 position in the work. The author confesses that 
 hopes were entertained years ago that the production 
 of faulty steam-jacketed cylinders would have ceased 
 before now. 
 
 But some of the abortions illustrated in the book 
 represent the' latest practice, and, as several of the 
 cylinder sections have figured very prominently in 
 our illustrated journals, they were evidently looked 
 upon by their producers as being worthy of notice. 
 
 Until these inefficient steam-jackets cease to be 
 built and tested, the contentions respecting cylinder 
 condensation and steam-jacketing will never be 
 settled.^ 
 
 It is astonishing to find how much has been 
 recently written on steam-jacketing, and how little 
 information of a practical kind has been imparted. 
 During recent years much valuable space has been 
 devoted by our technical journals to useless conten- 
 tions and theoretical investigations, but no one, it is 
 believed, has given any practical suggestions respecting 
 the requirements of thorough steam-jacketing.t An 
 
 * We have referred to a test carried out at Paisley, the small 
 economy of which is probably due to the small size of the pipe supply- 
 ing the jackets with steam : a very common fault among engine- 
 makers. 
 
 t Since the issue of the first edition, many writers have given the 
 results of their investigations ; there is not now the dearth of literature 
 on this subject that existed a few years ago. 
 
PREFACE TO THE SECOND EDITION xi 
 
 attempt has been made to set forth some rules which 
 may help the designer to produce steam-jackets, that 
 cannot fail to be beneficial. 
 
 If all the engines which have recently been tested 
 had been built in accordance with these requirements, 
 the results of such tests would have been so convinc- 
 ing an evidence in favour of steam-jacketing, that no 
 further discussion would be needed. 
 
 Trials carried out on thoroughly steam-jacketed 
 engines are still wanted, but no tests of engines pre- 
 tending to give results of jacketed and unjacketed runs 
 are of any real service, unless the conditions laid down 
 in this book for obtaining beneficial results are 
 complied with. Before any comparative figures are 
 accepted of jacketed and unjacketed engine trials, 
 sections of the cylinders, jackets, steam-supply and 
 drain-pipe arrangements should be clearly illustrated, 
 which is the only safeguard against fraud ; for, too 
 often in the past, faulty jackets have been tried 
 consequently showing a low economy and these 
 adverse results have been turned to account by a few 
 engineers who profess to believe that steam-jackets 
 are of little service. But, in every case where properly 
 jacketed engines have been thoroughly tested, the 
 results have proved, beyond a shadow of a doubt, the 
 advantage and economy of steam-jacketing. 
 
 This book closes with the results of such trials in 
 a tabular form, carried out on many different types of 
 engines during the last fifty years ; and the economy 
 gained by jacketing is shown to have ranged from 10 
 to 42 per cent. 
 
 The work has been written at odd moments out of 
 work hours, and no one more than the author is 
 sensible of its faults, but it is hoped that this book 
 may meet with a favourable reception, and be of 
 
xii PREFACE TO THE SECOND EDITION 
 
 service to everyone in any way connected with the 
 steam-engine. 
 
 The author is indebted to the proprietors of 
 Engineering and The Mechanical World for many of 
 the illustrations. He wishes to tender his thanks also 
 to Messrs. Crosby, Lockwood & Son for allowing an 
 illustration to appear from Haeder and Powles' Hand- 
 book of the Steam- Engine ; to Messrs. Hopkinson for a 
 similar privilege ; and to the Council of the Inst. of 
 Mechanical Engineers for permission to quote some 
 tables from the Second Eeport on the Value of the 
 Steam Jacket. He wishes to acknowledge, with 
 thanks, the blocks lent by Messrs. Kobey & Co. and 
 Messrs. Hornsby & Sons, and for the permission to use 
 some blocks from Mr. Chas. Day's work on " The Indi- 
 cator, &c.," which appeared in The Practical Engineer. 
 
 W. FLETCHER. 
 
 207 WOODBEIDGE ROAD, IPSWICH, 
 
 February, 1895. 
 
CONTENTS. 
 
 CHAPTER I. 
 
 HISTORY OF THE STEAM-JACKET. 
 
 PAGE 
 
 Watt the inventor of the Steam-Jacket Model of Newcomen 
 engine Wood cylinder Copper cylinders New boring 
 bar Watt's first patent Engine sent to Cornwall Watt's 
 first steam-jacket Watt's later steam-jackets Modern 
 Cornish engine cylinder Murdock's cylinder Steam 
 carriage Trevithick's cylinder First locomotive Woolf's 
 invention Maudsley's engine Headley's "Puffing Billy" 
 Tyndall's steam-carriage Beattie's sham steam-jackets 
 Grose's Cornish engine Flaycraft uses superheated steam 
 Parsons' exhaust-jacket Cambridge's portable engines 
 Hornsby's portable engines Clayton and Shuttleworth's 
 portable engines Martini's higher steam in jacket Magg's 
 portable engine Tuxford's engine Carlisle Show, 1855 
 Steam-heated pistons Robey's engines Cowper's "hotpot" 
 Newton's invention Royal Show, 1867 Royal Show, 
 1870 Steam-jackets first century Tredgold's mistaken 
 notion Value of the steam-jacket, . . . 1-18 
 
 CHAPTER II. 
 
 CYLINDER CONDENSATION. 
 Losses from External Radiation and Conduction. 
 
 Four sources of cylinder condensation Radiation Unlagged 
 cylinders Engines at the Crystal Palace, 1851 Oxford 
 Show, 1870 Clark's experiments Low-priced engines 
 Wasteful engines Non-conductors Box's experiments 
 Non-radiators Silicate cotton Air-spaces Steel plates 
 Leroy's composition Haake's remarks Starch and saw- 
 dust Cornish engine cylinder Sulzer engine, . . 19-28 
 
xiv CONTENTS 
 
 CHAPTER III. 
 
 CYLINDER CONDENSATION continued. 
 Losses from Internal Condensation. 
 
 PAGE 
 
 Conducting powers of cast-iron Initial condensation cooling 
 action of the clearance space Condensation and evapora- 
 tionSlow moving engines most wasteful Influence of the 
 condenser D. K. Clark on cylinder condensation A. E. 
 Cowper's experiments Professor Rankin's experiments 
 Example from practice Heat lost during admission Ex- 
 pansive working a source of loss Charles Day's remarks 
 Professor Unwin's tests of small steam-engines Plymouth 
 engine trials Newcastle engine trials Wet steam 
 Wasteful engines Vertical boiler tests Tubular boilers 
 M'Laren's remarks on priming Rich's experiments 
 Importance of steam-jackets on compound engines Triple- 
 expansion engine Sir F. Bram well's experiments Losses 
 in the high -pressure cylinders Priming boilers Croll's 
 suggestions Remedies, ..... 29-4 
 
 Work Condensation. 
 
 Steam condensed owing to the performance of work Professor 
 Rankine and Professor Clausius Liquefaction of steam 
 during expansion Glass cylinders Salter's remarks 
 Holmes on work condensation Glasgow engine trials 
 Exhaust-jacket acts as a condenser Remedy for work con- 
 densation Condensation removed from the cylinder to 
 the jacket, ....... 49-54 
 
 CHAPTER IV. 
 
 MEANS PROPOSED FOR PREVENTING INTERNAL CYLINDER 
 CONDENSATION. 
 
 Superheated steam. Superheating conduces to economy Diffi- 
 culties of superheating Holmes on superheated steam 
 Dry steam. Hot Air-Jackets Cylinders in smoke-box 
 Cylinders heated in flues Cylinder in chimney base 
 Northcott on hot air-jackets. Hot Water-Jackets Water 
 heated in boiler flue Perkins' apparatus Spiral ribs round 
 cylinder Cheap device. Non-Conducting Cylinders Non- 
 conductor and non-absorber of heat Many proposals 
 Wood cylinder Watt's wood cylinder Lignum-vitee in 
 
CONTENTS 
 
 xv 
 
 staves "Wood-lined piston and cylinder covers Smeaton's P AGK 
 wood-lined pistons Steel liner Lead proposed Pistons 
 covered with lead Porcelain Slate let into cylinder-lids 
 Slag glass liners Thurston's proposals Emery's trials 
 Bismuth proposed Experiments with glass and iron 
 cylinders Glass cylinder saved half the steam Smooth 
 surfaces are bad conductors of heat Rough surfaces cause 
 condensation. Polished Piston and Cylinder Covers Croll's 
 paper Initial condensation in triple -expansion engines 
 Rough pistons and covers Polished surfaces reduce con- 
 densation Trials carried out by Croll Rough surfaces 
 and excessive losses Torpedo boat engines Sulzer engines, 
 economy of Heated oils round cylinder Air and steam 
 combined Sturgeon's piston Compression Useful effect of 
 compression Northcott on compression, . . . 55-70 
 
 The Steam-Jacket. 
 
 Function misunderstood Watt's practice Tredgold's theory 
 Function Northcott's remarks on the steam-jacket Action 
 of the jacket Few cylinders properly jacketed Some of 
 the requirements for obtaining economical results Dry 
 steam Wet steam Higher pressure steam in jackets 
 Professor Unwin on the steam-jacket Cowper's experi- 
 ments Effect of the steam-jacket on indicator diagrams 
 Corliss engine Woolf beam engine Compound side-by- 
 side engine M'Laren's triple-expansion engine trials 
 Sulzer's triple expansion engine trials Remarkable results, 70-87 
 
 CHAPTER V. 
 
 THE ABUSE OF THE STEAM-JACKET. 
 Faulty Designing. 
 
 Ineffectual jackets Injurious jackets Mistaken notions 
 Faulty jackets made by English and foreign engineers 
 Economising influence of the jacket destroyed by faulty 
 designing Defective construction Inattention of the 
 engine-driver Abortive jackets Water-jackets Stapfer 
 on obstructed jackets Necessary requirements Jacket to 
 encircle cylinder Small exhaust-chambers Exhaust- 
 jackets Headley's "Puffing Billy" Seattle's jackets 
 American locomotive cylinder Corliss engine cylinder 
 American portable engine cylinder Full boiler pressure in 
 
CONTENTS 
 
 the jacket Murdock's jacket Trevithick's and Cam- ** AGE 
 bridge's jackets Hornsby's efficient jackets Steam taken 
 from valve-chest Small supply pipes Working steam 
 taken from the jacket Northcott's remarks Higher 
 pressure steam in jackets Dry steam in jackets Water 
 collector Water knocked out Jacket open to the boiler 
 Circulation required Air on top of jackets Air-jackets 
 Counterfeit jackets Mair on faulty jackets Bollinckx's 
 cylinder Engines at the World's Fair Drainage 
 neglected Maw's proposal Steam-traps Water-pockets 
 Jackets full of water Thin liners Thick liners- 
 Bush system of construction Hard brass liners Phosphor- 
 bronze liners Steel liners Allen on steel liners 
 Sir Joseph Whitworth's compressed steel liners Halpin's 
 heat-ribs Halpin's economical results Steam-heated 
 pistons Steam-heated covers Drainage Clearance 
 Short ports Separate steam and exhaust-ports Robey's 
 cylinder Corliss cylinder Large steam chests Un- 
 lagged cylinders D. K. Clark on exposed cylinders 
 Careful examples of lagging Cornish engine system of 
 lagging Clean engines Manner of testing, . . 88-138 
 
 CHAPTER VI. 
 
 THE ABUSE OF THE STEAM-JACKET continued. 
 Defective Construction. 
 
 Curious steam-jackets Bad workmanship Thick cylinder 
 walls Spongy castings Dummy jacketAir space 
 Water in jackets Cracked cylinder Cement jacket 
 Steam-tight liners, . . . . . . 139-144 
 
 CHAPTER VII. 
 
 THE ABUSE OF THE STEAM-JACKET continued. 
 Inattention on the part of the Engine- Driver. 
 
 Careless engine-drivers Drain-cocks Supply cocks Sir F. J. 
 Bramwell's remarks on engine-drivers Chief engineer 
 A converted fireman Jackets of marine engines badly 
 attended to Coath's observations respecting twenty-three 
 steamers Drain open to the condenser The jackets 
 abused Jackets shut off Jackets tampered with Auto- 
 matic drainage Efficient jacketing rarely understood 
 Draughtsman's responsibility Drawing-office care, . 145-152 
 
CONTENTS xvii 
 
 CHAPTER VIII. 
 
 PRACTICAL PROOF OF THE EFFICIENCY OF THE STEAM-JACKET. 
 
 Watt's engine trials Fifty years' experiments The steam- PAGE 
 jacket in Cornwall Trevithick's remarks Farey and Penn's 
 trials Humphries' trials Fairbairn Engineering Company 
 Pinchbeck's experiment Sir Titus Salt's engines- 
 Combe's trials Hirn's tests M 'Kay's experiments Bryan 
 Donkin's accurate experiments Portable engine trial 
 Farey and Donkin's tests Portable engine trials at Cardiff 
 Napier's marine engine tests Hallawer's experiments 
 Results of trials on marine engines Emery's remarks 
 Holmes on the steam-engine Donkin's experiments 
 Saltaire Corliss engines Low-pressure jacket Mair's 
 trials Chatham Waterworks' engines Cowper's remarks 
 on Rennie's trials Research committee's reports on the 
 value of the steam-jacket Small cylinder greater gain 
 Drain-pipe choked Delafond's trials Professor 
 Kennedy's and Donkin's experiments University 
 College engine Compound engine trials Low-pressure 
 cylinder jacketed Stapfer's remarks Professor 
 Kennedy's further trials Triple - expansion engine 
 trials Professor Osborne Reynold's experiments Davey 
 and Bryan's results of trials Donkin's experiments 
 Temperature of cylinder walls Hot water in jackets Half 
 speed trials Steam condensed in jackets Saving due to 
 jackets Superheating Dry exhaust steam Combe's 
 observations Guzzie's trials with higher pressure steam in 
 jackets Perkins' type of boiler Results of trials showing 
 saving due to jacketing during the last fifty years on 
 single cylinder non-condensing engines Single cylinder 
 condensing engines Compound condensing engines 
 Triple-expansion condensing engines, . . . 153-202 
 
 APPENDIX. 
 
 Steam-saving appliances MThail and Simpson's steam gener- 
 ator Royle's steam dryer Lancaster and Tonge's steam- 
 traps Royle's syphonia steam-trap Llewellin and James's 
 steam-trap Dawson's return steam-trap United States 
 metallic packing Green's economiser Shore's heater 
 Exhaust steam injector Whyte and Cooper's evaporative 
 
xviii CONTENTS 
 
 condenser Pi-cell's automatic expansion gear Phosphor 1>A(;! ' 
 bronze cylinder liners Granger's forced draught Mel- 
 dram's forced draught Copley and Turner's filter 
 Bollinckx's steam engines Hopkinson's indicator Lan- 
 caster and Tonge's pistons and rings for piston valves- 
 Conclusion, ...... 203-210 
 
 DIRECTORY OF MAKERS OF FUEL-SAVING APPLIANCES, . 219 
 
LIST OF ILLUSTRATIONS. 
 
 FIG. 
 
 1. Watt's first steam-jacketed cylinder, 
 
 2. Watt's second steam-jacketed cylinder, 
 
 3. Murdock's cylinder inserted in the boiler, . 
 
 4. Trevithick's cylinder inserted in the boiler, 
 
 5. Cambridge's portable engine cylinder, 
 
 6. Hornsby's compound portable engine cylinder, 
 
 7. Diagram showing loss by cooling, . 
 
 8. Diagram showing initial condensation and evaporation, 
 
 9.' Diagrams showing water consumption in relation to cut-off, 
 10. Diagrams showing water consumption in relation to cut-off, 37 
 ll! Diagrams from small engine at the Plymouth Trials, 
 
 12. Diagram from compound engine at the Plymouth Trials, . 40 
 
 13. Diagram from unjacketed compound engine, 
 14.' Diagram from unjacketed compound engine, 
 
 15. Diagram from unjacketed compound engine, 
 
 16. Diagram showing gain due to steam-jac'keting, 
 
 17. Diagram showing gain due to steam-jacketing, 
 
 18. Diagram showing loss in unjacketed cylinder, 
 
 19. Robey's stationary engine cylinder, 
 
 20. Diagram from Corliss steam -jacketed engine, . 78 
 
 21. Diagram from steam -jacketed Woolf engine, 
 
 22. Diagram from same engine with jackets shut off, . 
 23! Combined diagram from jacketed compound engine, 
 
 24*. Combined diagram from M'Laren's triple-expansion engine, 
 
 25. Portable engine cylinder of faulty design, . 
 
 26. Portable engine cylinder of faulty design, . 
 27.' Traction engine cylinder of faulty design, . 
 
 28. Outside locomotive cylinder, 
 
 29. Stationary engine cylinder badly drained, . 
 
 30. Portable engine cylinder of faulty design, . 
 
 31. Traction engine cylinder, . 
 
 32. Stationary engine cylinder, . 
 
 33. Corliss engine cylinder showing small clearance, 
 
 34. The " Porter" engine steam -jacketed cylinder, 
 
 35! Corliss engine cylinder, faulty exhaust outlet, . . 100 
 
xx LIST OF ILLUSTRATIONS 
 
 FIG. PAGE 
 
 36. Corliss engine cylinder, approved design, . .101 
 
 37. Steam ports of stationary engine cylinder, . . . 102 
 
 38. Steam ports of stationary engine cylinder, . . . 102 
 
 39. Stationary engine cylinder, faulty jacket supply, . . 103 
 
 40. Stationary engine cylinder, faulty jacket supply, . .103 
 
 41. Stationary engine cylinder, faulty design, . . . 104 
 
 42. Cornish engine cylinder, efficiently jacketed, . . 105 
 
 43. Corliss engine cylinder, approved design, . .108 
 
 44. Corliss engine cylinder, approved design, . . . 109 
 
 45. Portable engine cylinder, draining pipe, . . .110 
 
 46. Portable engine cylinder, . . . . .111 
 
 47. Traction engine cylinder, deficient circulation, . .112 
 
 48. Stationary engine cylinder, efficient design, . .115 
 
 49. Compound engine cylinder, efficient design, . .117 
 
 50. Compound engine cylinder, efficient design, . . 119 
 
 51. Frikart compound engine cylinder, . . . .121 
 
 52. Corliss engine cylinder, showing small clearance, . .122 
 
 53. Compound portable engine cylinders, efficient design, . 124 
 
 54. Jacket drain, . . . . . .129 
 
 55. Portable engine cylinder, jacket drain, . . . 130 
 
 56. Steam -jacketed cylinder cover, . . . .131 
 
 57. Steam-jacketed cylinder cover, . . . .131 
 
 58. Compound tramway locomotive cylinder, efficient design, . 132 
 
 59. Compound tramway locomotive cylinder, efficient design, . 133 
 
 60. Steam-jacket inlet-pipe and stop-valve, . , . 135 
 
 61. Compound traction engine cylinder, . . . 136 
 
 62. Diagram from compound engine, with jacketed cylinders, 173 
 
 63. Diagram from compound engine, without jacketed 
 
 cylinders, .... .174 
 
THE STEAM-JACKET 
 PRACTICALLY CONSIDERED. 
 
 CHAPTEE I. 
 
 HISTORY OF THE STEAM-JACKET. 
 
 THE Steam-Jacket is one of the numerous details 
 of the modern steam-engine which owes its origin to 
 the illustrious Watt, and, like many other of his valu- 
 able inventions, it was the outcome of several years 
 of earnest thought and experiment, commencing from 
 the time that the steam-engine first became the sub- 
 ject of his study, until the jacket was included in the 
 well-known patent specification of 1769. 
 
 While Mr. Watt was repairing the model of a New- 
 comen steam-engine in 1763, it occurred to him that 
 a large portion of steam must be condensed without 
 doing any work by being turned into a cold cylinder, 
 this condensation representing a considerable loss. He 
 aimed at reducing this waste, and said to himself : 
 " Let me make an engine, working by a piston, in 
 which the cylinder shall be continually hot and per- 
 fectly dry." 
 
 A 
 
2 HISTORY OF THE STEAM-JACKET 
 
 He therefore set to work with this object in view, 
 by making his cylinders of substances that would 
 receive and give out heat slowly. A small engine was 
 soon constructed with a 6-inch cylinder " made of 
 wood, soaked in linseed oil, and baked to dryness." 
 By numerous experiments made with this engine he 
 found that this reduced the internal condensation ; 
 but, owing to other reasons not named, but easily 
 conceived, he was obliged to abandon wood as a 
 material for the construction of his cylinders. He 
 next surrounded his metal cylinders with an outer 
 wooden case, and filled the intervening space with 
 ashes. Another engine was made in 1765, the inner 
 " cylinder of which was formed of copper not bored, 
 but hammered, and not very true : " it was enclosed 
 in a wooden jacket or steam-case. Mr. Watt preferred 
 sheet-copper to cast-iron for his cylinders, for the 
 convenience of adjusting them : the castings in those 
 days could not be depended upon, and to procure 
 a round and parallel hole in a cylinder was an im- 
 possibility. Mr. Watt, when speaking to Dr. Eoebuck 
 about one of his model engines (with a steam-jacket 
 round the cylinder), complains " that the cylinder had 
 been so badly bored that it was -Jth of an inch larger at 
 one end than the other," and only a trifle better were 
 those that were considered a good job; for, on one 
 occasion, Mr Boulton, in writing to his partner, said 
 in effect, " that the completion of the bore of a cylinder 
 by a new boring- bar * was most satisfactory ; the 
 piston fitted so nicely that there was scarcely room 
 for the insertion of a half-crown at the worst part." 
 Mr. Watt applied his first steam-jacket, most probably, 
 to the engine erected at a coal-mine on the estate 
 of the Duke of Hamilton, at Kinniel. The cylinder 
 
 * Invented by W Murdock. 
 
WATTS INVENTION 3 
 
 of this engine was made of cast-iron, 18 inches 
 diameter, inclosed in a wooden steam-case. This 
 being a sort of experimental engine, it was continually 
 altered and improved, until it was brought to consider- 
 able perfection. During the erection of this engine 
 Mr. Watt applied for a patent to secure the profits of 
 his ingenuity, which was enrolled in April 1769.^ 
 
 The steam-jacket was introduced into Cornwall 
 about 1776 : it was applied to an engine having a 30- 
 inch cylinder, erected at a mine near Chacewater. In 
 1783 Mr. Watt writes: "We have altered all the 
 engines in Cornwall but one, and many in other parts 
 of England : " and, from that time to this, the steam- 
 jacket has held its own in that county, notwithstand- 
 ing the attempts which have been made to discontinue 
 it, these attempts being attended with a palpable loss 
 of power. 
 
 It has recently been asserted that Watt imperfectly 
 understood the theory of the steam-jacket. We can- 
 not stay here to dispute this point. We may say, 
 however, with all our glittering theory and much 
 vaunted knowledge, we do not jacket our cylinders so 
 wisely or so well as Watt did more than a hundred 
 years ago. Whatever theoretical knowledge Watt 
 possessed on this subject is of little moment, but it is 
 
 * The following are Mr. Watt's own words concerning his invention : 
 "My methods of lessening the consumption of steam, and, conse- 
 quently, fuel in fire-engines, consists in the following principles : First, 
 that the vessel in which the powers of steam are to be employed to 
 work the engine, which is called the cylinder in common fire-engines, 
 and which I call the steam vessel, must, during the whole time 
 the engine is at work, be kept as hot as the steam which enters 
 it; first, by enclosing it in a case of wood or any other materials 
 that transmit heat slowly ; secondly, by surrounding it with steam 
 or other heated bodies ; and, thirdly, by allowing neither water, or 
 other substances colder than the steam, to enter or touch it during 
 that time." 
 
4 HISTORY OF THE STEAM-JACKET 
 
 well known that he displayed remarkable ability in 
 all his steam-jacketing arrangement. He was quite 
 clear respecting the beneficial results obtained from 
 the steam-jacket, for he says : " We have also 
 
 Fig. 1. Watt's first steam-jacketed cylinder. 
 
 executed some engines without the outside cylinders 
 (jackets) altogether ; but we have no reason to applaud 
 our economy, as the consumption of coal was consider- 
 ably greater." It is well known that Watt could only 
 introduce his steam-engines by giving them away, and 
 
.* 
 
 UNIVERSITY 
 
 VATT8 VOW 
 
 contenting himself with one-third of the saving in fuel 
 compared with the Newcomen engines of the period. 
 A careful study of Watt's methods for lessening the 
 consumption of steam cannot but prove of interest. 
 
 In Watt's first steam-jacketed cylinder, the steam 
 would constantly press upon the top of the piston in 
 the same way as the atmosphere had previously done 
 in Newcomen's engines. 
 
 Fig. 1 shows this interesting steam-jacketed cylinder, 
 from which it will be seen that, during the up-stroke 
 of the piston, by closing the valve communicating 
 with the condenser, and admitting steam into the 
 bottom of the cylinder, the piston would be placed 
 in equilibrium, and so be carried to the top of the 
 cylinder by the weight of the pump-rods. To produce 
 the down-stroke, the passage between the steam-jacket 
 and the bottom of the cylinder being closed, and that 
 between the bottom of the cylinder and the condenser 
 being opened, a vacuum was created under the piston, 
 and the steam acting upon the top of it, would drive 
 it to the bottom of the cylinder; the piston-rod 
 passed through a stuffing-box in the top of the steam- 
 jacket. 
 
 Fig. 2 shows Watt's later steam-jacketed cylinder ; 
 the steam-case was put together round the cylinder in 
 segments united by bolts. In the earlier instances 
 the steam for the internal cylinder was taken from 
 the jacket, but in the illustration the steam was drawn 
 from the main steam-pipe : * the jacket was drained by 
 means of a long syphon pipe, which conveyed the con- 
 densed steam from the bottom of the jacket into the 
 hot well of the condenser. A socket-joint, packed 
 with hemp and tallow, was provided in the steam- 
 case, to allow a little end-wise movement in case of 
 
 * The steam inlet to. the jacket is not shown in the drawing. 
 
HISTORY OF THE STEAM-JACKET 
 
 Fig. 2. Watt's second steam -jacketed cylinder. 
 
MURDOCHS CYLINDER 7 
 
 any difference in the expansion of the jacket or 
 the cylinder. 
 
 In Watt's later engines the steam-jacket was 
 supplied with steam direct from the boiler, the inlet 
 being placed at the top, and made of ample area. 
 The jacket was drained effectively : the drain returned 
 the condensed steam from the lowest part of the 
 jacket to the water space of the boiler by gravitation. 
 
 We have dwelt at some length on Watt's examples 
 of steam-jacketing, so as to make our historical notes 
 more complete, and, we trust, of greater interest. 
 
 In another part of the book we illustrate a modern 
 Cornish pumping-engine steam-jacketed cylinder, show- 
 ing the steam-supply pipe, the drain-pipe, and the 
 method of lagging adopted by some engine-builders (see 
 fig. 42). 
 
 Although Mr. Watt left the steam-jacket very 
 much as we have it to-day, yet there have been 
 numerous alterations suggested in the interval that 
 has elapsed between his day and ours. Some of these 
 suggestions are really improvements, others are at- 
 tempts to introduce various means in lieu of the jacket 
 for attaining the same end ; while many display a 
 great amount of ignorance on the part of the inven- 
 tors, and, as a consequence, their so-called improve- 
 ments are worse than useless. We have only space 
 for noticing one or two of these absurdities in passing, 
 confining ourselves very briefly to the steam-jacket's 
 career. 
 
 In 1781 W. Murdock made a model locomotive 
 for common roads, the cylinder of which was placed 
 on the top of and partly let into the steam-space of 
 the copper boiler (see fig. 3). When Murdock was 
 testing the powers of this interesting little engine one 
 very dark night, on a narrow road at Eedruth, after 
 
8 HISTORY OF THE STEAM-JACKET 
 
 lighting the spirit lamp under the boiler the locomo- 
 tive started off with a fizzing sound, at such a pace 
 
 Fig. 3. Murdock's cylinder inserted in the boiler. 
 
 as to leave its inventor in full chase after it. During 
 this experimental trip " he heard distant despair-like 
 
TREVITHICK'S CYLINDER 9 
 
 sounds : it was too dark to perceive objects, but he 
 found the cries for assistance proceeded from the 
 worthy pastor, who, going into town on business, was 
 met on this lonely road by the fiery monster, whom 
 he took for the evil one in propria, persona." Mur- 
 dock took out a patent in 1799 for some improvements 
 in steam-engines, among the rest a new method of 
 forming jacketed cylinders. The cylinder casing 
 was cast in one piece, to which the cover and bottom 
 of the steam-cylinder were attached. The liner placed 
 within was fixed to the case at one end by conical 
 joints, and by a packed or caulked joint at the other. 
 Three years later Trevithick and Vivian obtained a 
 patent for a " high-pressure engine, the cylinder of 
 which was enclosed within the boiler ; the nozzle, 
 steam-pipe, and bottom were cast in one piece to resist 
 the strong steam " (fig. 4). In 1803 they made a 
 common road locomotive, the cylinder being fixed 
 within the boiler horizontally. In 1804 they con- 
 structed a high-pressure engine for moving carriages 
 on rails, which proved a success ; this engine was em- 
 ployed in a mine at Methyr Tydfil, and drew carriages 
 containing 10J tons at the rate of 5J miles an hour; 
 its cylinder was let into the boiler vertically. It was 
 suggested that " placing the cylinder inside the boiler 
 saved the expense of a jacket, and effectually kept up 
 the temperature of the cylinder to that of the steam." 
 Arthur Wolff employed steam of still higher pres- 
 sure, and, to keep up the temperature of his cylinders, 
 a separate fire was made under the steam-jacket, 
 which was fitted with a safety-valve. In 1804 he 
 obtained another patent for raising the cylinder to any 
 temperature, without admitting high pressure steam 
 into the jacket, by the use of oil, fat, wax, or other 
 substances that melt without being turned into vapour. 
 
10 
 
 HISTORY OF THE STEAM-JACKET 
 
 About this time Henry Maudslay constructs the 
 most elegant engine of its day: the cylinder was en- 
 
 Fig. 4. Trevithick's cylinder inserted in the boiler. 
 
 closed in a casing of copper, and the annular space 
 filled with wool. 
 
 Early in 1813 the celebrated " Puffing Billy," 
 designed by W. Headley and constructed by J. Foster, 
 commenced to run on the Wylam Railway ; this 
 patriarchal locomotive may be seen in the Patent 
 
PUFFING BILLY 11 
 
 Museum at South Kensington. The working cylin- 
 ders on each side are dropped into wrought-iron 
 jackets : some engineers have assumed that these were 
 bond fide steam-jackets, but there is now no doubt that 
 these jackets did not serve such a useful purpose, but 
 were used as receivers, into which the exhaust steam 
 was admitted previous to its passing into the chimney, 
 a pipe being provided for this purpose. 
 
 In 1814 Thomas Tyndall obtained a patent for an 
 engine adapted to give motion to carriages, in which 
 the exhaust was led into a case surrounding the cylin- 
 der, to preserve its heat. The absurd notion of keeping 
 the outside of a cylinder at the same heat as the in- 
 side, by means of the comparatively cool exhaust, was 
 not confined to the Puffing Billy's designer, or the 
 individual just named, but this idea has been repeatedly 
 mentioned by so-called steam-engine improvers since 
 that date. It has three or four times been embodied 
 in inventors' specifications, the most notable instance 
 being in Mr. J. Beattie's patent specification of 1858, 
 actually forty-four years after Tyndall's day ; and, in 
 another instance, as recently as 1862. Surely this 
 wasteful fallacy does not still prevail among engineers, 
 but there are plenty of cylinders in our day, which, if 
 not totally encircled by the exhaust steam, are so 
 badly arranged as to be very nearly so. 
 
 About the year 1825 Captain S. Grose erected a 
 Cornish pumping-engine, in which he considerably 
 increased the pressure of stearn, and obtained very 
 good results ; the cylinder was carefully steam-jacketed, 
 and, with a view to prevent any loss of heat from 
 radiation, the cylinder, nozzles, and steam-pipe were 
 carefully clothed with non-conducting materials. He 
 subsequently erected an 80-inch cylinder engine, in 
 which these improvements were introduced, and this 
 
12 
 
 HISTORY OF THE STEAM-JACKET 
 
 Fig. 5. Cambridge's portable engine cylinder. 
 
MESSRS. HORNSBY' S CYLINDER 13 
 
 engine being manufactured and erected with peculiar 
 care, did an extraordinary duty in 1828. 
 
 W. F. Flaycraft, in 1830, uses superheated steam, 
 and he heats the cylinder by a fire. 
 
 During the year 1842 P. M. Parsons keeps the 
 cylinders of locomotive engines warm by allowing 
 steam to have passage between the jacket and the 
 cylinder. 
 
 To Cambridge, of Market Lavington, must the 
 honour be accorded for having first attempted to heat 
 the cylinders of portable engines, his first engine being 
 made in 1843 : it was his practice to place the cylin- 
 ders vertically on the top of the boilers, and let them 
 into the steam-space like Murdock's little road engine 
 (see fig. 5). Cambridge built a large number of engines, 
 which were sold in various counties in England. He 
 hardly made two engines alike. The vertical engines 
 with the cylinders let into the boiler eventually gave 
 place to the engine placed horizontally on the top of 
 the boiler : some engines made by Cambridge of this 
 design are still at work. 
 
 The portable engines made by Messrs. E. Hornsby, 
 in 1850, were fitted with the cylinder inside the steam 
 space of the boiler, similar to the method adopted by 
 Trevithick in his steam carriages. Messrs Hornsby 
 make compound portable engines on this system to 
 this day. Fig. 6 shows the latest arrangement : the 
 two cylinders and valve-chests are inserted in the 
 elevated steam-space at the fire-box end of the boiler ; 
 the whole steam-dome being well lagged, making a 
 very efficient steam-jacket. 
 
 In 1853 Clayton and Shuttleworth obtained a 
 patent for their portable engines fitted with the steam- 
 cylinder placed within the smoke-box, and also steam- 
 jacketed, a combination that had not been used before. 
 
14 HISTORY OF THE STEAM-JACKET 
 
 In 1854 Frederick Martini patented a method of 
 supplying the jackets of steam-engines with steam of 
 a higher pressure than that which is being admitted 
 into the working cylinder. He says : " If the steam 
 
 Fig. 6. Hornsby's compound portable engine cylinder. 
 
 in the cylinder has a pressure of three atmospheres, 
 that in the steam-jacket should have a pressure of 
 five atmospheres. The steam to produce this effect 
 
MESSRS TUXFORUS CYLINDER 15 
 
 should be generated in a small, strong, separate boiler." 
 It is curious to find the same thing re-patented thirty 
 years afterwards, viz., 1884 Here are the inventor's 
 own words : " A method of increasing and maintain- 
 ing the heat of steam used for working engines. It 
 is usual to apply to the cylinders of steam-engines 
 steam-jackets for the purpose of maintaining the heat 
 of the working steam, and many attempts have been 
 made to superheat the steam before it reaches the 
 cylinder. These expedients are more or less ineffective, 
 because the stearn in the jacket is not hotter than 
 the steam entering the cylinder, and because super- 
 heating apparatus are generally complex and far from 
 -durable. Now, according to our invention, we remedy 
 these defects by employing a separate boiler, which 
 may be comparatively small, and generating in it 
 steam at a higher pressure and temperature than that 
 of the working steam in the main boilers. We employ 
 either the steam or the hot water of this auxiliary 
 boiler for circulating through the jackets encasing the 
 working cylinders. Thus, by conduction from the 
 hotter fluid, the heat of the working steam is increased 
 and maintained." 
 
 This is a slight digression we will now proceed 
 with the historical notes. A few months after 
 Martini's patent, Oliver Maggs placed the cylinders 
 of his portable engines in the base of the chimney to 
 prevent the loss of heat. 
 
 Several other agricultural engineers, besides those 
 already named, commenced to jacket the cylinders of 
 their portable engines about this time. Tuxford's 
 prize portable at the RA.S.E. Show at Carlisle, in 
 1855, had a jacketed cylinder. 
 
 Steam-jacketed or heated pistons were introduced 
 in 1856 by C. B. Normand, who says : " In engines 
 
10 HISTORY OF THE STEAM-JACKET 
 
 acting expansively, the cylinder is often jacketed, 
 which protects the sides and ends only ; to remedy 
 this defect, the piston-rod and piston are made hollow, 
 and steam at its maximum pressure is introduced into 
 the piston." 
 
 Eobey & Co., in 1857, used jacketed cylinders on 
 their portable engines, and the Eeading Iron Works 
 Co. also obtained three prizes at the E.A.S.E. Show 
 at Worcester, in 1863, with engines having steam- 
 jacketed cylinders. 
 
 Mr A. E. Cowper, in 1862, patented a method of re- 
 heating the steam of compound engines during its pas- 
 sage from the high-pressure to the low-pressure cylinder, 
 viz., by inclosing the receiver in a steam-jacket. 
 
 In 1863 Newton proposed to line the interior of 
 cylinders with metal surfaces, heated by steam from 
 an auxiliary boiler at about 100 F. above the working 
 pressure in the boiler : the linings of the cylinder lids 
 were made of two circular steel plates i^th of an inch 
 thick, kept 1J inches apart, and filled with steam ; the 
 barrel of the cylinder was got up in a similar manner. 
 
 At the Eoyal Agricultural Society's trials of fixed 
 engines at Bury St. Edmunds, in 1867, the first prize 
 engine had a steam-jacketed cylinder and covers ; the 
 second prize engine had the cylinder only, jacketed. 
 At the same trials of single cylinder portable engines, 
 the first prize engine had a steam-jacketed cylinder 
 inclosed inside the smoke -box ; the second prize 
 engine had a steam-jacketed and carefully clothed 
 cylinder on the top of the boiler. There was an 
 engine with an exhaust jacket partly round the cylin- 
 der, which burnt just twice as much coal per hour as 
 the first prize engine did. 
 
 During the trials of vertical engines and boilers 
 combined, at the Oxford Show of the Eoyal Agricul- 
 
THE STEAM-JACKET AN ECONOMIZER 
 
 tural Society, in 1870, it was shown that the engines 
 having the cylinders not steam-jacketed, and the 
 boilers not clothed, burnt from 50 to 250 per cent, 
 more coal per horse-power than those having the 
 cylinders jacketed and the boilers lagged. 
 
 We have traced merely in outline the first century 
 of the steam-jacket's history, viz., from 1770 to 1870 ; 
 during this period the most conflicting opinions have 
 been entertained by engineers concerning its value ; 
 at one time it enjoyed very little favour, and was only 
 fitted to engines of one class ; at another time it was 
 the rule to jacket nearly all engines ; while at another 
 period it was all but abandoned for all classes of 
 engines, its application being very exceptional indeed ; 
 it can, however, be easily shown that whenever doubts 
 have been entertained by persons respecting the utility 
 of the steam-jacket, these misgivings have been occa- 
 sioned by an imperfect knowledge of the function 
 of the jacket : for instance, Tredgold, the foremost 
 engineer and writer of his day, held erroneous notions 
 respecting the theory of the jacket ; consequently, his 
 opinions on this subject are of no value whatever ; 
 and numerous other smaller writers and less known 
 engineers have been similarly misinformed, and have 
 thus lightly esteemed the services of the steam-jacket 
 as an economizer. We have also noticed, in passing, 
 some of the plans that have been suggested for effect- 
 ing the same ends by other means than steam -jacket- 
 ing ; not one of which, however, has been successfully 
 applied : among many others the use of hot-air jackets 
 may be mentioned. 
 
 To give full particulars of the various methods of 
 perfect steam-jacketing that have been introduced 
 between 1870 and the present time would require 
 more space than has been occupied by this chapter, 
 
 B 
 
18 HISTORY OF THE STEAM-JACKET 
 
 for it is now the custom to thoroughly steam-jacket 
 the cylinders of all classes of engines, save one, manu- 
 factured by firms of repute, and some of the means 
 adopted by the best makers to secure the highest 
 efficiency are worthy of more extensive imitation ; for, 
 notwithstanding our increased knowledge, there is 
 still room for much improvement in the so-called 
 cheap productions of some makers, which are designed 
 in such a manner that economy of fuel is out of the 
 question : let us hope, however, that such engines will 
 soon become more rare, because of a decreased demand 
 for such abortions existing among buyers. 
 
 By numerous tests, carried out on all classes of 
 engines, under all circumstances, the steam-jacket has 
 proved itself beyond a shadow of a doubt to be of im- 
 mense service in promoting economy ; hence the steam- 
 jacket is to-day more universally applied than ever it 
 was, because its value is more universally understood. 
 
CHAPTEE II. 
 
 CYLINDER CONDENSATION. 
 Losses from External Radiation and Conduction. 
 
 THE working steam within the cylinder of a steam- 
 engine is robbed of its heat and liquefied by the four 
 following causes : 
 
 (1) Some heat passes through the metal of the cylin- 
 der body and ends, which is absorbed by the metal 
 of the bed-plate or engine-frame in contact with the 
 cylinder. 
 
 (2) Heat is rapidly transmitted through the walls 
 and lids of the cylinder to the atmosphere, unless it 
 is checked or prevented by the application of non- 
 conducting and non-radiating materials. 
 
 (3) The greatest amount of heat, however, is wasted 
 by the internal surfaces of the cylinder being cooled 
 down during the exhaust by exposure to the atmos- 
 phere or to the frigorific influence of the condenser : 
 this metal has to be warmed up by the incoming 
 steam during every stroke of the engine, representing 
 an enormous loss in unjacketed cylinders. 
 
 (4) Steam is condensed resulting from the perform- 
 ance of work : this liquefaction takes place inside the 
 cylinders of unjacketed engines, and within the jackets 
 of steam-jacketed engines. 
 
 I. Some heat passes through the metal of the cylin- 
 der body and ends, and is absorbed by the metal of the 
 
20 CYLINDER CONDENSATION 
 
 bed-plate or engine-frame in contact with the cylinder. 
 Very little need be said respecting the heat trans- 
 mitted from the cylinder to the bed-plate, because, in 
 modern engines, a very small proportion of the one is 
 in contact with the other. The loss from this source 
 may be reduced to a minimum by a judicious arrange- 
 ment of the materials on the part of the engine 
 designer. But, even in badly-arranged engines, the 
 loss of heat conducted from the cylinder to the frame 
 must be very slight. It has, however, been proposed 
 to place strips of non-conducting materials between 
 the parts of the cylinder in contact with the engine 
 bed-plate, so as to prevent this useless expenditure 
 of heat. 
 
 II. Heat is rapidly transmitted through the walls 
 and lids of the cylinder to the atmosphere, unless it 
 is checked or prevented by the application of non- 
 conducting and non-radiating materials. 
 
 Much heat is conducted through the cylinder sides 
 and ends, and lost by radiation if left exposed. Eadia- 
 tion is the transmission of heat by direct rays from a 
 hot body through space, just as light is from a luminous 
 body. The rapidity with which heat radiates varies, 
 other things being equal, as the square of the tempera- 
 ture of the hot body is in excess of the temperature 
 of the cold one, so that a body if made twice as hot 
 will lose a degree of temperature in a quarter of the 
 time ; if made three times as hot, it will lose a degree 
 of temperature in one-ninth of the time ; and so on, 
 in all other proportions.^ 
 
 The loss by radiation is not affected by the form of 
 the radiant body : a cube or cylinder will radiate the 
 same amount of heat with equal areas under the same 
 * " Treatise on Heat," by Thomas Box. 
 
CYLINDER LAGGING 21 
 
 conditions. The amount of heat emitted by radiation 
 will vary exceedingly with the nature of the surface, 
 being increased by darkness and roughness, and 
 diminished by smoothness and polish. 
 
 The loss of heat from a dull black surface by 
 radiation being 100, that for polished metal does not 
 exceed 5. 
 
 A few years ago many engine cylinders were left 
 totally exposed, notwithstanding that Watt in his time 
 had clearly gained a marked economy by carefully 
 clothing his cylinders. Most of the portable engines 
 exhibited and tested at the Crystal Palace, in 1851, 
 had exposed cylinders : it is not surprising to find that 
 the average consumption of coal during these trials 
 was 14 Ibs. per ind. horse-power per hour ; and we 
 have mentioned elsewhere that at the trials carried 
 out by the Royal Agricultural Society at Oxford in 
 1870, the engines with unjacketed cylinders and un- 
 lagged boilers burnt from 50 to 250 per cent, more 
 fuel per horse-power than some other engines having 
 the cylinders steam-jacketed and clothed, and the 
 boilers carefully coated with some non-conducting 
 material. 
 
 Some experiments, made by Mr. D. K. Clark, show 
 that, in the case of exposed cylinders of locomotive 
 engines, the loss from radiation may rise to as much 
 as 40 per cent, of the whole steam consumed, and by 
 careful clothing this loss may be reduced to 2 per 
 cent. 
 
 Few engines at the present day, however, are seen 
 with unlagged cylinders, and these few belong to low- 
 priced and abortive types used on steam-cranes, ships- 
 winches, direct- acting pumps, &c. We regret to say 
 that the steam-engines having unlagged cylinders are 
 often found working out of doors, exposed to all 
 
22 CYLINDER CONDENSATION 
 
 weathers : the waste of steam in such cases must be 
 enormous. It is very unfortunate that there should 
 be any demand for low-priced wasteful engines, when 
 well-designed and excellent engines of all classes may 
 now be had at very reasonable rates, fitted with steam- 
 jacketed and carefully-clothed cylinders : the rest of 
 the details are also arranged by competent engineers 
 for working economically. 
 
 Happily, these examples of second-rate construction 
 are becoming every day more exceptional ; the standard 
 of efficiency is gradually being raised ; steam-jacketing 
 and lagging are more general now than ever they were 
 heretofore. 
 
 There are an immense number of non-conducting 
 compositions introduced for the purpose of preventing 
 the radiation of heat from boilers, steam-pipes, and 
 cylinders. 
 
 " It should carefully be borne in mind, although it 
 is constantly forgotten, that whether the protective 
 material is, or is not a first-rate non-conductor, unless 
 its qualities as a non-radiator are also good, it cannot 
 prove wholly satisfactory." * By increasing the thick- 
 ness of low conductors the loss of heat becomes rapidly 
 less, but, " with moderately good conductors, the loss 
 with all thicknesses is greater than by a naked cylinder, 
 and the thicker the casing the greater the loss." .t A 
 12-inch cylinder, filled with steam at 212 and exposed 
 to external air, will lose twenty-four times as much heat 
 per square foot run, if left naked, than if it were lagged 
 with felt or wood 6 inches thick, or eleven times more 
 if left naked than with 2 inches of lagging. According 
 to the table quoted from Box's " Treatise on Heat," given 
 on the next page, it will be seen that the best material, as 
 
 * The Engineer, 10th March 1876. 
 
 t " Treatise on Heat," by Thomas Box. 
 
NON-CONDUCTORS OF HEAT 23 
 
 far as non-conduction goes, is grey blotting-paper; the 
 quantity of heat transmitted per square foot in one 
 hour by a block of this material 1 inch thick being 
 only '274 of a unit, while a plate of iron of the same 
 thickness transmitted 233 units per square foot, the 
 difference in temperature at the opposite sides of the 
 plate being one degree. 
 
 TABLE I. Conducting Power of Materials, leing the 
 quantity of heat in units transmitted per square 
 foot per hour ~by a plate 1 inch thick, the two 
 surfaces differing in temperature 1. From the 
 Experiments of Pe'clet. 
 
 Copper, ...... 515 
 
 Iron, . . . . . 233 
 
 Zinc, 225 
 
 Lead, 113 
 
 Marble, grey, fine-grained, . . 28 
 
 Stone, calcareous, fine, . . . 16 '7 
 
 Glass, 6-6 
 
 Baked clay, brickwork, . . . 4'83 
 
 Plaster, ordinary, . . . 3 '8 6 
 
 Brick-dust, sifted, . . . 1'33 
 
 Coke, pulverised, .... 1'29 
 
 Cork, 1-15 
 
 Chalk, in powder, .... '869 
 
 Charcoal of wood, in powder, . . '636 
 
 Straw, chopped, .... ''563 
 
 Wood ashes, - . . . . . < '531 
 
 Mahogany dust, . . . . '523 
 
 Canvas of hemp, new, . . . '418 
 
 Calico, new, . . . . '402 
 
 White writing-paper, . . . '346 
 Cotton-wool and sheep wool (any density), '323 
 
 Eiderdown, ~ . . . '314 
 
 Blotting-paper, grey, . . . '274 
 
24 
 
 CYLINDER CONDENSATION 
 
 It must be borne in mind that Table I. gives only 
 the conducting power of materials, and does not refer 
 to radiation. 
 
 The power of radiation is influenced by the surface 
 of materials ; roughness increases the radiation, while 
 smoothness diminishes it. Table II. shows this very 
 clearly. 
 
 TABLE II. The Radiating Power of Bodies, being the 
 units of heat emitted per square foot per hour for 
 a difference in temperature of 1. From the 
 Experiments of Pdclet. 
 
 Silver, polished, 
 
 Copper, polished, . 
 
 Tin, polished, 
 
 Zinc and brass, polished, 
 
 Tinned^iroii, polished, 
 
 Sheet-iron, polished, 
 
 Sheet-lead, 
 
 Sheet-iron, ordinary, 
 
 Glass, .... 
 
 Cast-iron, new, 
 
 Chalk, .... 
 
 Cast and s}ieet-iron, rusty, 
 
 Wood sawdust, fine, 
 
 Building-stone, plaster, wood, 
 
 Sand, fine, 
 
 Calico, .... 
 
 Woollen stuffs, any colour, 
 
 Silk stuffs, oil-paint, 
 
 Paper, any colour, . 
 
 Lamp-black, . 
 
 Water, .... 
 
 Oil, .... 
 
 brick , 
 
 026527 
 
 03270 
 
 04395 
 
 04906 
 
 08585 
 
 09200 
 
 13286 
 
 56620 
 
 59480 
 
 64800 
 
 6786 
 
 686$ 
 
 7215 
 
 7358 
 
 7400 
 
 7461 
 
 7522 
 
 7583 
 
 7706 
 
 8196 
 
 1-0853 
 
 1-4800 
 
SILICATE COTTON 25 
 
 Silicate cotton or slag-wool possesses advantages as 
 a non-conductor of heat : it is largely used by the 
 Admiralty. Some railway companies have adopted it 
 for covering their locomotive boilers. The follow- 
 ing relative conducting powers are interesting : 
 
 Silicate cotton, . . . . 100 
 
 Hair-felt, ..... 117 
 
 Cotton- wool, ..... 122 
 
 Sheep's wool, . . . ., . 136 
 
 Charcoal, . . . . . 143 
 
 Sawdust, ..... 163 
 
 The following experiment was recently carried out 
 to test the heat-resisting qualities of silicate cotton. 
 A cake, 2 inches thick, covered on both sides with a 
 wrought-iron plate J of an inch thick, was placed over 
 a fire ; when the bottom plate was made red-hot, the 
 top plate was warm but not hot. 
 
 Very few people have any idea of the extent to 
 which heat can be retained by non-conducting sub- 
 stances. In one of the mines of the Comstock Lode 
 (America), a shaft burned out, and, five months after, 
 when the dffiris of the fire was cleared away, locks at 
 the bottom of the shaft were found to be still red- 
 hot.^ In this we have an example of the effects of 
 properly covered cylinders, steam-pipes, &c., by good 
 non-conducting materials. 
 
 Air spaces are often recommended as effective non- 
 conductors of heat, but it has been remarked by Professor 
 Ordway that the air spaces should be filled up with a 
 material that will act as entangler, because air at such 
 a temperature as 311 F., for instance, corresponding 
 to a steam pressure of 180 Ibs. per square inch, is of 
 little or no value as a non-conductor, unless something 
 
 * Address by Mr. J. C. Bayles of New York, in 1876. 
 
 UNIVEHSITY 
 
26 CYLINDER CONDENSATION 
 
 is used to prevent the air from moving. A small 
 quantity of hair-felt or wool will play the part of 
 entangler. There are many non-conducting composi- 
 tions which are unsatisfactory they are anything but 
 non-radiators. If such materials are covered with 
 cold-rolled steel-sheets this defect will be remedied, as 
 these smooth steel plates stand pretty high among the 
 non-radiators. The smoother and brighter the sheets 
 that are used for lagging cylinders, steam-chests, and 
 pipes, the more satisfactory they are as non-radiators. 
 
 Many engine-makers coat their cylinders with a 
 good non-conducting composition, and cover the whole 
 with bright steel plates, which act perfectly for retain- 
 ing the heat. We now wish to combat an opinion 
 which is firmly established in the minds of many users 
 of steam, viz., that the outside temperature of a non- 
 conducting composition applied to hot surfaces is a 
 measure of its non-conducting efficiency. It has been 
 proved that the act of measuring the temperature, 
 either on the outside by placing the hand upon the 
 covering, or even by thermometer readings, are unre- 
 liable and misleading. Good non-conductors will not 
 allow the heat to escape quickly, but retain it in the 
 surface just as tenaciously as in the interior, because 
 they are also good non-radiators, in which case the 
 supply of heat from the steam inside is greater than 
 the loss of heat from the surface, and, consequently, the 
 outside feels warm. Inferior non-conductors, however, 
 give the heat from the surface quicker to the surround- 
 ing space than it can be supplied from the interior 
 source of heat ; thus it can happen that the outside 
 surface feels cooler, when, in fact, it loses more heat 
 than the better covering.^ 
 
 One of the oldest non-conducting compositions which 
 
 * Mr, Albert Haake in The Practical Engineer, 14th June 1889. 
 
SA W-D UST AND STARCH 27 
 
 is in use at the present time is that manufactured by 
 Messrs. F. Leroy & Co. It has been improved from 
 time to time, and is now, as heretofore, giving satisfac- 
 tion. Messrs. Leroy can show some composition which 
 has been ten years on steam-heated surfaces without 
 the least apparent change. 
 
 A non-conducting coating for cylinders, steam-pipes, 
 &c., is described in a recent issue of the Eevue Indus- 
 trielle as being conveniently applied and cheap, while 
 it can be prepared by any steam-user. It consists of 
 a mixture of wood sawdust, with common starch, used 
 in a state of thick paste. If the surfaces to be 
 covered are well cleaned from all trace of grease, the 
 adherence of the paste is perfect for either cast or 
 wrought-iron, and a thickness of 1 inch will produce 
 the same effect as that of the most costly non-conduc- 
 tors. For copper pipes there should be used a prim- 
 ing coat or two of potter's clay, mixed thin with water, 
 and laid on with a brush. The sawdust is sifted to 
 remove too large pieces, and mixed with very thin 
 starch. A mixture of two-thirds of wheat starch 
 with one-third of rye starch is the best for this purpose. 
 It is the common practice to wind string spirally 
 around the pipes to be treated, keeping the spirals 
 about | inch apart to secure adhesion for the first 
 coat, which is about J inch thick. When this' is set, 
 a second and third coat are successively applied ; and 
 so on, until the required thickness is attained. It is 
 stated that twenty shillings worth of starch will go 
 as far in this way as 40 spent in many commercial 
 non-conductors of heat. 
 
 The conduction and radiation of heat from cylinders 
 may be very much reduced, if not practically pre- 
 vented, by a liberal application of non-conducting and 
 non-radiating materials, which are so easily obtainable. 
 
28 CYLINDER CONDENSATION 
 
 In another part of the book we refer to the method of 
 protecting Cornish engine cylinders. And we give 
 another example of careful clothing, as carried out by 
 an American firm also. 
 
 The following note refers to the lagging of the 
 triple-expansion engine, made by Messrs. Sulzer Bros., 
 Winterthur, which has given such remarkable results, 
 recorded later on: "The jackets are well covered 
 with an insulating substance, and are clothed with 
 polished steel-sheets and bright cast-iron covers." 
 
CHAPTEK III. 
 
 CYLINDER CONDENSATION continued. 
 Losses from Internal Condensation. 
 
 III. THE greatest amount of heat, however, is wasted 
 by the internal surfaces of the cylinder being cooled 
 down during the exhaust by exposure to the atmos- 
 phere, or to the frigorific influence of the condenser : 
 this metal has to be warmed up by the incoming 
 steam during every stroke of the engine, representing 
 an enormous loss in unjacketed cylinders. 
 
 This liquidation of steam inside uu jacketed engine- 
 cylinders is caused by the rapid conducting powers of 
 cast-iron of which the cylinder, piston, and cylinder 
 lids are made, for these surfaces most readily absorb 
 and emit heat. 
 
 To explain more fully how this internal condensation 
 takes place, let us imagine the case of a non-condens- 
 ing steam-engine with the cylinder unjacketed, the 
 piston of which is being moved towards one end by 
 the incoming steam. At the other end the exhaust 
 port is open to the atmosphere, so that the tempera- 
 ture of the surfaces of the piston, cylinder-walls, lids 
 and steam passages being thus exposed, are reduced to 
 the same temperature as the exhaust steam (or, say, of 
 boiling water) by the time the piston has completed 
 its stroke. 
 
30 CYLINDER CONDENSATION 
 
 The admission port opens, and steam of 60 or 80 
 Ibs. pressure enters the cylinder : while this is taking 
 place a considerable quantity of heat is extracted from 
 the incoming steam to warm up the cylinder ; hence 
 a large portion of the steam which first enters the 
 ' ' cylinder is condensed by the piston-face and cylinder- 
 lid, and its place is immediately supplied from the 
 boiler. Ten Ibs. of steam might be sufficient if no 
 condensation occurred ; but condensation does take 
 place, and a further quantity of steam is admitted to 
 keep up the pressure. Instead of 10 Ibs. per stroke 
 being required, we may have an admission of 15 Ibs. 
 to 20 Ibs. One portion of the steam goes to heat up 
 the cylinder, the rest to fill up the space behind the 
 piston." It has been well said by The Engineer that 
 " nothing can be more efficient as a condenser than 
 the thin space due to clearance intervening between 
 the cylinder-lid and the piston-face, both reduced to 
 the temperature of the exhaust steam." When the 
 slide-valve closes, we have not steam alone, but steam 
 and hot water ; expansion now commences, and the 
 pressure is gradually reduced ; the water lying in the 
 cylinder, which was condensed during the admission 
 of the steam, is now in contact with the heated walls 
 of the cylinder, while the pressure in the cylinder has 
 diminished to, say, 5 or 6 Ibs. pressure : the result of 
 this is, that the water which was condensed by the 
 cool metal is in part re-evaporated, and the terminal 
 pressure of the steam is slightly raised in consequence. 
 It has often been asserted that all the power that was 
 lost by condensation is regained by evaporation, but 
 this is a mistake, for the power was lost when the 
 steam was at its highest pressure, and regained at 
 some other pressure very much lower, and much too 
 late to be of any real service, while the cylinder 
 
WASTEFUL ENGINES 31 
 
 is cooled by the loss of heat in boiling off this 
 water. 
 
 Thus, without steam-jackets, a large quantity of 
 steam passes through the cylinder in the form of water 
 without doing any work. Indeed, the cylinder acts 
 to some extent as " a condenser at the beginning, and 
 as a boiler at the end of the stroke." This waste of 
 steam varies in different types of engines ; for instance, 
 in fast-running engines the loss is considerably less 
 than for slow-moving engines, because so much less 
 time is allowed for the cooling of the metal. In long- 
 stroke engines of medium diameter of cylinder, the 
 piston and lids (for they certainly are the greatest 
 agents of condensation) contribute less to this waste 
 than for short-stroke engines of large diameter of 
 cylinder. The higher the steam pressure used, the 
 greater the difference of the temperature of the metals 
 at admission and exhaust, therefore the larger the loss. 
 The most wasteful are slow-moving, unjacketed, ex- 
 pansive condensing engines, for the " evil influence of 
 the condenser on unjacketed cylinders is a matter of 
 notoriety." 
 
 The quantity of steam thus condensed in various 
 classes of engines has been approximately estimated. 
 For information concerning this liquidation in locomo- 
 tive engine-cylinders, we will quote the following by 
 Mr. D. K. Clark, who says : " I made a large number 
 of trials and observations, and I conclusively proved 
 that the loss of steam by condensation in outside 
 cylinders of locomotive engines was enormous ; the 
 loss increased with the degree of expansion or the 
 shortness of the cut-off, until, for a cut-off of ^th half, 
 the steam was condensed when admitted into the 
 cylinder." The same author says, in his work Steam 
 and the Steam-engine, p. 268 : " In the cylinders 
 
32 
 
 CYLINDER CONDENSATION 
 
 of ordinary steam-engines the extra consumption and 
 waste of steam devoted to the heating of the cylinders 
 in the first part of the stroke is above 12 per cent, of 
 the whole steam consumed for a period of admission 
 of one-third of the stroke." From indicator diagrams, 
 taken by Mr. E. A. Cowper, which are illustrated in 
 the Cyclopaedia of Useful Arts, the amount of loss 
 from the want of a steam-jacket is clearly demonstrated. 
 These figures show the pressure really attained, to- 
 
 
 
 Fig. 7. 
 
 gether with the true expansion curve for the whole 
 quantity of steam that entered the cylinder dotted in, 
 and which dotted curve would have been described 
 if the cylinder had been steam-jacketed. The differ- 
 ence between these curves represents the amount of 
 loss from the lack of steam-jacketing : in one diagram 
 this loss amounts to 11*7 per cent.; in another to 
 19*66 per cent., there being rather more variation of 
 temperature in this case, owing to there being more 
 expansion ; in the next figure the loss is 27'27 per 
 
INITIAL CONDENSATION 33 
 
 cent. ; whilst in the last diagram, which we reproduce 
 by jig. 7, the loss rises to the formidable proportions of 
 44*58 per cent. 
 
 Professor Kankine, in his work on the Steam- 
 Engine, says : " In some experiments the quantity 
 of steam wasted through alternate liquefaction and 
 evaporation in the cylinder has been found to be 
 greater than the quantity which performed the work.' 7 
 
 From articles which appeared some time ago in 
 The Engineer on " Condensation in Steam-Engine 
 Cylinders," it is shown that 9 Ibs. of steam per horse- 
 power per hour are lost in the cylinder of a steam- 
 engine through internal condensation : cylinder 3 feet 
 diameter and 5 feet stroke, the engine making 30 
 revolutions per minute, the absolute pressure of steam 
 being 75 Ibs. per square inch, and steam is admitted 
 through one foot of the stroke, and expanded through 
 4 feet. 
 
 The consumption of steam in practice of such an 
 engine would be 27 Ibs. per horse-power per hour. The 
 theoretical quantity of steam needed per horse-power 
 per hour is stated to be only 13*7 Ibs. : we must there- 
 fore in some way account for the difference of 13'3 Ibs. 
 
 Theoretical quantity required per ind. 
 
 horse-power per hour, . . . 13*7 
 
 Loss by leakage per ind. horse-power per 
 
 hour, TO 
 
 External condensation, &c., per ind. horse- 
 power per hour, . . . . 0'3 
 
 15-0 
 
 The remaining 12 Ibs. of steam is condensed inside 
 the cylinder 3 Ibs. will be condensed by the mere 
 performance of work. After making all these allow- 
 
 c 
 
34 
 
 CYLINDER CONDENSATION 
 
 ances, there yet remains 9 Ibs of steam per indicated 
 horse-power per hour; and this 9 Ibs. is assumed to 
 be liquefied by the unjacketed cylinder as we have 
 explained. 
 
 This internal condensation may be made clear to 
 the eye by the aid of indicator cards, which are repro- 
 duced for this purpose. " This conduction of heat to 
 and from the metal of the cylinder has the effect of 
 lowering the pressure at the beginning and raising it 
 at the end of the stroke ; the lowering effect being, on 
 the whole, greater than the raising effect. The general 
 
 nature of the change thus produced in the diagram is 
 shown by the dotted line G, H, I, C, F, in fig. 8. 
 
 Mr. D. K. Clark, in his little work Steam and the 
 Steam-Engine, 1885, says : " When steam is admitted 
 into the cylinder while the latter is colder than the 
 steam, a very sensible condensation of the steam takes 
 place during admission, in the process of heating the 
 cylinder to the temperature of the steam, which 
 continues to a certain extent during the period of 
 expansion. A portion of this heat, though but a small 
 part, passes off and is lost ; the remainder is retained 
 by the cylinder until it is re-absorbed by the pre- 
 
LOCOMOTIVE CYLINDERS 35 
 
 cipitated steam during the expansion of the remaining 
 steam, if it be long enough continued ; that is, until 
 the temperature of the latter falls below that of the 
 cylinder. This is a destructive process, occasioning an 
 absolute loss of steam ; and the amount of steam thus 
 injuriously precipitated, and but partially revived, 
 increases rapidly in proportion as the steam is earlier 
 cut off and expansion is extended." This condensa- 
 tion and re-evaporation is exemplified in a diagram 
 taken from an outside-cylinder locomotive, and repro- 
 duced at p. 269 of Mr. Clark's book, to which we 
 must refer our readers. Dotted lines show the expan- 
 sion curve which would have been described with a 
 constant weight of steam ; the full lines show the expan- 
 sion curve produced by the indicator ; the fall of the 
 pressure at the beginning, and the rise at the end of 
 the stroke are shown by the full lines, producing an 
 effect similar to the diagram already given at fig. 8. 
 
 Outside cylinders have not many supporters on 
 English railways. The chief drawback is the great 
 loss of heat from internal condensation. Proof of this 
 can be derived from Mr. D. K. Clark's paper " On the 
 Behaviour of Steam in the Cylinders of Locomotives 
 during Expansion,"^ from which it would appear that 
 the difference of initial condensation between inside 
 and outside cylinders, taken from six inside and fifteen 
 outside engines, is, on an average something like 16 
 per cent. 
 
 " In many text-books on the steam-engine, the fact 
 that increased work can be obtained from a given 
 quantity of steam by utilizing its expansive property 
 is fully gone into ; but, unfortunately, this statement 
 is not unfrequently given without any qualification ; 
 consequently, many people believe that the earlier the 
 * Minutes of Proceedings Inst. C.K, vol. Ixxii., p. 275. 
 
36 CYLINDER CONDENSATION 
 
 cut-off in any cylinder the greater the economy. This, 
 however, is only true within certain limits, as it is 
 found that, after a certain point in any engine, the loss 
 introduced by cylinder condensation more than counter- 
 balances the gain by increased expansion. We give 
 two most instructive diagrams to show the increased 
 water consumption owing to internal condensation in 
 unjacketed cylinders. Fig. 9 shows three diagrams 
 taken from a horizontal non-condensing engine by a 
 
 showing reduced economy as cut-off gets earlier owing to 
 increased cylinder condensation. 
 
 Fig. 9. 
 
 well-known maker. The calculated water consump- 
 tion is given on each curve. From these it will be 
 seen that, instead of decreasing as the cut-off got earlier, 
 the water consumption increased ; proving that, although 
 the steam was expanded to a greater extent, the gain 
 thus obtained was outweighed by the increased con- 
 densation losses." * Fig. 10 shows three diagrams 
 
 * The diagrams and remarks are taken by permission from a series 
 of papers on "The Indicator and its Diagrams," by Mr. Chas. Day, 
 Wh.Sc., which recently appeared in The Practical Engineer. 
 
VERTICAL ENGINES 37 
 
 from an unjacketed condensing engine ; the water 
 consumption is given at each grade of expansion, again 
 showing the losses that take place by attempting to 
 work at high rates of expansion in an unjacketed 
 cylinder. The adoption of a good steam-jacket in 
 both these instances would have considerably reduced 
 the water consumption at all grades of expansion. 
 
 We regret to say that small unjacketed vertical 
 engines are now being most extensively adopted for 
 
 Diagrams from condensing engine, illustrating same point as fig.^. 
 Fig. 10. 
 
 driving dynamos for electric-lighting purposes, and the 
 amount of steam consumed by some of these wasteful 
 abortions is, we believe, never realised by the users, 
 and known only to those who have tested the engines, 
 or to others who have had the privilege of stoking the 
 boiler supplying them with steam. Professor Un win's 
 tests of the three small steam-engines sent for competi- 
 tion in the trials of the Eoyal Agricultural Society's 
 meeting at Plymouth, 1890, was a serious revelation 
 to many, showing, as he did, by the results, the extreme 
 
38 
 
 CYLINDER CONDENSATION 
 
 wastefulness of the engines working without steam- 
 jacketed cylinders, and using sloppy steam from vertical 
 boilers. The following table shows the figures:'^ 
 
 TABLE III. 
 
 SUMMARY OP RESULTS. 
 
 No. l. 
 
 No. 2. 
 
 No. 3. 
 
 Boiler. 
 
 
 
 
 Water evaporated per Ib. of coal from feed 
 
 8'726 
 
 7-65 
 
 5-978 
 
 Equivalent evaporation from and at 212, . 
 "Water evaporated per sq. ft. of heating 
 surface per hour, . . . Ib. 
 
 10-42 
 3-09 
 
 9-065 
 9-71 
 
 7-136 
 7-80 
 
 Engine, 
 
 Piston speed in feet per minute, . 
 Indicated horse-power, .... 
 Brake horse-power, ..... 
 
 298-1 
 5-641 
 5-042 
 
 263-0 
 5-175 
 3-997 
 
 240-3 
 6-201 
 5-003 
 
 Steam. 
 
 
 
 
 Steam used per indicated horse-power per 
 hour, ...... Ib. 
 
 35-75 
 
 64 '73 
 
 57-75 
 
 Coal. 
 
 
 
 
 Per indicated horse-power, . . Ib. 
 
 4-099 
 
 8-461 
 
 9-66 
 
 It will be seen from the table that the compound 
 engine No. 1 required 35*75 Ib. of steam per indicated 
 horse-power, while the others required 64'7 Ib. and 
 577 Ib. respectively. The real ratios of expansion 
 were No. 1, 44 ; No. 2, 1-2 ; and No. 3, 1-6. 
 
 These facts have been very clearly brought out by 
 Professor Unwin in his report, from which the two 
 instructive diagrams (figs. 11 and 12) are copied.t 
 " Each diagram is constructed from the mean of the 
 measurement of three or four good diagrams, taken 
 
 * Engineering, 14th November 1890. 
 
 t Figs. 11 and 12 are inserted by the kind permission of the Pro- 
 prietors of Engit 
 
PLYMOUTH ENGINE TRIALS 
 
 39 
 
 during the trial, and is thus representative of the 
 average conditions of working. On each diagram is 
 
 s '> 
 
 CyUrv&cr Vo 
 iagram from .s 
 
 drawn a dotted saturation curve, obtained by calculat- 
 ing the volume of steam admitted to the cylinder at 
 
40 
 
 CYLINDER CONDENSATION 
 
 each stroke, and set out on the supposition that none 
 of it is condensed. The space between the actual and 
 the ideal expansion curves represents the loss at any 
 moment by cylinder condensation or by the wetness 
 of the steam." Fig. 11 reveals that with a boiler 
 pressure of 75 Ibs. the highest cylinder pressure in the 
 No. 3 engine was only 60 Ibs. About 40 per cent, of 
 
 Messr Simpson Strickland &-C 
 
 Votum* of Oybnders tn c ft>. 
 Fig. 12. Diagram from small compound engine at the Plymouth Trials. 
 
 the steam admitted did nothing but warm the cylinder 
 walls. The diagram of engine No. 2, not given here, 
 shows less than half the steam that calculation demon- 
 strates should be in the cylinder. Fig. 12 shows a 
 great amount of loss in the No. 1 engine from con- 
 densation and re-evaporation. The steam-jacket is 
 most beneficial in small steam-engines ; the extra cost 
 is very trifling, and we think that it is a great pity 
 
NEWCASTLE ENGINE TRIALS 
 
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 ^2 
 
 H 
 
 i 
 
 
 
 1 
 
 4J 
 
 M 
 
 & 
 
 1 
 
 pC) 
 
 1 
 
 i 
 
 
 
 | 
 
 'ff 
 
 
 
 1 
 
 9 
 
 i 
 
 
 
 
 
 
 S 
 
 1 
 
 M 
 
 i 
 
 s 
 
 o 
 
42 CYLINDER CONDENSATION 
 
 that such engines as the above should be manufactured 
 without steam-jackets. 
 
 By way of contrast, we now give similar figures 
 obtained from three of the small simple and compound 
 engines tested at the Eoyal Agricultural Show at 
 Newcastle in 1887. The boilers in these tests were of 
 the locomotive type, the cylinders were steam-jacketed, 
 and the feed- water was heated. The Newcastle results 
 are just as creditable as the Plymouth results are dis- 
 graceful. 
 
 We leave the tables to speak for themselves. 
 
 It has already been said that some of the waste of 
 steam in the Plymouth engines is due to the wet steam 
 produced by the vertical boilers. From experience we 
 have had in boiler testing, we are led to believe that 
 many of the evaporative tests of vertical boilers are 
 inaccurate. Much of the water said to be evaporated 
 has never been evaporated at all ; but is carried with 
 the steam into the cylinder to aggravate the great 
 waste arising from the heating and cooling action of 
 an unjacketed cylinder.* We give the following table 
 to show that, when a boiler supplied dry steam, a 
 
 * Since writing the above, we have read Mr. John M 'Laren's paper on 
 "The Economical Use of Steam in Colliery Engines," in which he says : 
 "Tubular, or water-tube boilers, are largely used on the Continent 
 and in America, and they are coming into somewhat limited use in 
 this country. Their economy, however, is doubtful, and, in actual 
 tests, a great disparity in results has been noted, the evaporation vary- 
 ing from 7 to 10 Ibs. of water per Ib. of coal ; but, even with the higher 
 evaporation, their economy is not by any means established, as it is 
 well known that their construction induces priming to a greater or less 
 extent, so that the duty obtained from the boiler is more apparent 
 than real. In priming, the steam, of course, carries a certain amount 
 of water in the form of spray in suspension, which is an absolute dis- 
 advantage to the engine, though it makes the evaporation of the boiler 
 appear very good." 
 
 Judging by the Sulzer engine trials, given later on, the water-tube 
 boiler certainly made dry steam. 
 
VERTICAL ENGINES 
 
 43 
 
 smaller quantity was required to do the same amount 
 of work than when the steam was wet. 
 
 TABLE V. Small Vertical Engine and Boiler Trials. 
 
 
 3. 
 S 
 
 11 
 
 ill 
 
 3* 
 
 TYPE OF VERTICAL BOILERS. 
 
 li 
 
 II 
 
 11 
 
 8 
 
 lil 
 
 W3 
 
 S3 
 
 II 
 
 Steam pressure above atm., . Ibs. 
 
 80 
 
 80 
 
 80 
 
 80 
 
 Duration of test in hours, . . 
 
 3-941 
 
 3-641 
 
 3-65 
 
 4-208 
 
 Brake horse-power, . ' . 
 
 10-15 
 
 10-35 
 
 10-54 
 
 10-38 
 
 Water required per brake horse-power 
 per hour, .... Ibs. 
 
 50-64 
 
 48-87 
 
 45-57 
 
 4473 
 
 Water evaporated from and at 212 
 per Ib. of coal, .... 
 
 10-28 
 
 9-31 
 
 8-88 
 
 9-83 
 
 Coal required per brake horse-power 
 per hour, .... Ibs. 
 
 8-39 
 
 8-92 
 
 8-72 
 
 7-69 
 
 The same engine was tested with each boiler: the 
 brake and conditions were alike in all the trials. It 
 will be seen that the boiler in the fourth column 
 produced dry steam, whereas the boiler in the first 
 column supplied wet steam to the engine. Less dry 
 steam was required per hour to develop more power 
 on the brake, with a reduced coal consumption also. 
 
 The engine was not fitted with a steam-jacketed 
 cylinder : a simple governor and equilibrium throttle- 
 valve were used. The engine and boilers were similar 
 to the simple engines tested at Plymouth. The results 
 are anything but satisfactory : they are given here for 
 the purposes named above, and also to show the ex- 
 cessive wastefulness of these small unjacketed steam- 
 
44 
 
 CYLINDER CONDENSATION 
 
 Leaving these small steam-engines, we will now 
 turn our attention to some large compound condensing- 
 engines. 
 
 We cannot do better than quote what the late Mr. 
 Kich said respecting this part of our subject. 5 ^ In 
 compound engines, with the cylinders not steam- 
 jacketed, working at a low speed, water is always 
 present in the low-pressure cylinder at a temperature 
 
 Fig. 13. 
 
 considerably below that of the steam exhausted by 
 the high-pressure cylinder. The result is, that so 
 much steam is condensed by this water and the cold 
 cylinder walls on its first admission, as to make 
 an enormous fall between the final pressure in the 
 high-pressure cylinder and the initial in the low-pres- 
 sure cylinder ; and, at the same time, the low-pressure 
 
 * " The Comparative Merits of Engines for Pumping," by Mr. W. E. 
 Rich, M.Inst.C.E., 1884. 
 
LARGE PUMPING ENGINES 
 
 45 
 
 diagrams are greatly reduced in their dimensions ; 
 sometimes to so large an extent as to become almost 
 worthless. An example of such a diagram is given 
 in fig. 13. 
 
 In experiments made in 1877 on an engine of the 
 compound principle, with unjacketed cylinders, Mr. 
 Eich found that, unless special arrangements are made 
 for removing this water, the low-pressure cylinder it- 
 self, and the water within it, will frequently remain 
 
 Fig. 14. 
 
 comparatively cold for hours after the engine has been 
 started ; and, even when an escape-valve is provided 
 for removing the water, such a cylinder only warms 
 up slowly in the first place. In the engine which he 
 tested he found that, at one hour thirty minutes after 
 starting, the water in the cylinder top when steam 
 was being admitted had only a temperature of 150; 
 at two hours fifteen minutes it was 155; at three 
 hours five minutes it was 175; at four hours fifty- 
 five minutes it was 192; but, having once gained 
 
46 
 
 CYLINDER CONDENSATION 
 
 such a temperature as the last-named, its further 
 advance was very rapid, if the escape-valve remained 
 open ; and the engine appeared suddenly to work more 
 freely, and to be capable of developing considerably 
 more power than before. For instance, the escape- 
 valve, fitted to the top of the low-pressure cylinder, 
 was opened to discharge the water above the piston 
 on one occasion when the temperature of that water 
 was 187; two minutes later its temperature was 
 198; three minutes later 204. Twelve minutes 
 
 Fig. 15. 
 
 after the valve had been shut off the temperature had 
 fallen to 185; but, in two minutes after opening, it 
 rose to 202. A diagram (fig. 14) was taken of the 
 engine two hours after starting, when the temperature 
 of the water in the cylinder was 150; and a diagram 
 (fig. 15) five hours after starting, when it had risen to 
 above 200. In the first case the low-pressure cylinder 
 shows a mean indicated pressure of only 4*43 Ibs. per 
 square inch, and it does only 24 per cent, of the whole 
 work of the engine ; while in the second case, it 
 indicates 8*32 Ibs. per square inch and does 41 per 
 
ENGINES FOR PUMPING 47 
 
 cent, of the whole work of the engine. Messrs. Easton 
 and Anderson had adopted steam-jackets largely previ- 
 ously ; but these experiments so thoroughly convinced 
 them of the great importance of having steam-jackets 
 in all cases on both cylinders, that they have since 
 made no compound engines without them. 
 
 From Mr. Kich's paper on " Engines for Pumping, " we 
 take two more diagrams (figs. 16 and 17) to exemplify 
 the effect of steam-jacketing, and the injurious effect 
 
 Fig. 16. 
 
 of any moisture left in the cylinder. Fig. 13 was 
 given as an extreme case of high expansion in un- 
 jacketed cylinders where the low-pressure diagram 
 was considered to be worthless. The two diagrams 
 (figs. 14 and 15) were also from unjacketed cylinders 
 working slowly at 12 to 13 revolutions per minute ; 
 the first taking one hour and a half, and the second 
 five hours after starting, without materially altering 
 the load. Figs. 16 and 17 were from steam-jacketed 
 
48 
 
 CYLINDER CONDENSATION 
 
 cylinders of the same comparative volumes, viz., 
 4 to 1, and working under very similar circum- 
 stances. Comparing the highly expansive diagrams 
 (figs. 13 and 16), it will be seen how much larger the 
 low-pressure card was in the jacketed cylinder (fig. 16) ; 
 and the same remark applied on comparing figs. 14, 
 15, and 17. In fig. 14 the maximum steam pressure 
 indicated in the low-pressure cylinder was below the 
 atmosphere ; while in fig. 17 it was 15 Ibs. above the 
 atmosphere. These diagrams confirmed graphically 
 
 Fig. 17. 
 
 the many other evidences of the immense gain due 
 to steam-jackets, especially in slow-speed engines.^ 
 
 It is a well-known fact that the condensation of 
 steam in the triple-expansion engine under ordinary 
 circumstances is greater than in any other type of 
 engine. Sir Frederick Bramwell in one case found that 
 45 per cent, of the whole steam that came to the 
 engine was condensed in the high-pressure cylinder of 
 a triple-expansion engine. Other engineers have re- 
 * Discussion on Mr. Rich's paper on " Engines for Pumping," 1884. 
 
WET STEAM 49 
 
 corded as much as 30 to 32 per cent, lost by condensa- 
 tion in the high-pressure cylinder of the same type 
 of engine. One writer has said that " under all cir- 
 cumstances he has found the high-pressure cylinder of 
 triple-expansion engines drowned with water. It was 
 impossible to get a dry diagram from it." Another 
 authority writes as follows : " I always find the high- 
 pressure cylinder wet. I cannot account for it in any 
 other way than I believe that all marine 'boilers send 
 a very large quantity of water into the cylinder, and 
 what is termed cylinder condensation is really prim- 
 ing."^ The steam-jacketing of many triple-expansion 
 engines is badly carried out. Take the Sulzer engine 
 as a model for efficient steam-jacketing. The ends are 
 well jacketed and drained ; and, above all, the pistons 
 and cylinder covers exposed to the incoming steam 
 have a smooth surface. Let Mr. Croll's suggestions 
 be carried out, and we shall have less trouble with 
 cylinder condensation in the triple-expansion engine. 
 
 The remedies for checking the loss of heat by ex- 
 ternal radiation and conduction were dealt with in 
 Chapter II. But the greater losses of internal con- 
 densation are not so easily remedied : the many pro- 
 posals for reducing these wastes must be dealt with 
 separately in another chapter, leading up to thorough 
 steam-jacketing, the only successful means at present 
 employed for reducing these sources of loss. 
 
 Work Condensation. 
 
 IV. Steam is condensed resulting from the perform- 
 ance of work : this liquefaction takes place inside the 
 cylinders of unjacketed engines and within the jackets 
 of steam-jacketed engines. 
 
 * Mr Mudd, West Hartlepool. 
 
 D 
 
50 CYLINDER CONDENSATION 
 
 The phenomenon of the liquefaction of steam by 
 expansive working was detected in 1849 by Professor 
 Rankine in England and Professor Clausius in 
 Germany, about the same time, but quite independently 
 of each other. This condensation, due to the work 
 done by the steam, is explained in the following 
 passage from Rankine on The Steam Engine : 
 
 " When steam or other saturated vapour in expand- 
 ing performs work by driving a piston, and receives 
 no heat from without during the expansion, a portion 
 of it must be liquefied is confirmed by experience in 
 actual steam-engines ; for it has been ascertained that 
 the greater part of the liquid water which collected in 
 unjacketed cylinders, and which was once supposed to 
 be wholly carried over in the liquid state from the 
 boiler (a phenomenon called priming), is produced by 
 liquefaction of part of the steam during its expansion. 
 This liquefaction does not, when it first takes place, 
 directly constitute a waste of heat or energy, for it is 
 accompanied by a corresponding performance of work. 
 It does, however, afterwards, by an indirect process, 
 diminish the efficiency of the engine ; for the water 
 which becomes liquid in the cylinder, probably in the 
 form of mist and spray, acts as a distributer of heat 
 and equalizer of temperature, abstracting heat from 
 the hot and dense steam during its admission into 
 the cylinder, and communicating that heat to the cool 
 and rarefied steam which is on the point of being dis- 
 charged; and thus lowering the initial pressure and 
 increasing the final pressure of the steam, but lower- 
 ing the initial pressure much more than the final 
 pressure is increased ; and so producing a loss of 
 energy which cannot be estimated theoretically. 
 Accordingly, in all cases in which steam is expanded 
 to more than three or four times its initial volume, it 
 
DRY STEAM*J?F CAI i F nRH\^-X^ 61 
 
 has in practice been found advantageous to envelop 
 the cylinder in a steam-jacket. The liquefaction 
 which would otherwise have taken place in the cylinder, 
 takes place in the jacket instead, where the presence 
 of the liquid water produces no bad effect ; and that 
 water is returned to the boiler." * 
 
 The fact of the partial condensation of saturated 
 steam expanding without receiving heat from external 
 sources is not dependent for proof upon theory only. 
 
 The expansion may be accomplished in a glass 
 cylinder, when a cloud or mist will be observed to 
 form, which is due to condensation, since dry steam is 
 invisible.t We give particulars of Mr. Cowper's ex- 
 periments with glass cylinders in another chapter. 
 
 This film of moisture acts as a most excellent 
 medium for the interchange of heat between the steam 
 and the cylinder walls. Perfectly dry steam is a very 
 indifferent radiator and conductor of heat, while moist 
 steam is comparatively good in both respects. Now, 
 the presence of water in the cylinder, by increasing 
 the moisture of the steam, aids in the rapid transmis- 
 sion of heat from the latter to the metal sides ; and, 
 vice versa, the power of the sides in transmitting heat 
 to the exhaust steam is enormously increased by the 
 presence of a film of water, which, as fast as it evapo- 
 rates, takes up heat from the metal with great rapidity. 
 The presence of water in the cylinder always exists 
 when the expansion is carried beyond a certain limit ; 
 and this is one of the reasons why excessive expansion 
 in a non-compound engine is unattended by any 
 economy.^ 
 
 At some trials of small steam-engines at Glasgow 
 
 * A Manual of the Steam Engine and other Prime Movers, 1876. 
 t Economy in the Use of Steam, by the late Mr. F. Salter, 1874. 
 J The Steam Engine, Holmes, 1887. 
 
52 
 
 CYLINDER CONDENSATION 
 
 in 1888, one of the makers attempted to use a very 
 high range of expansion with 80 Ib. steam, namely, 
 about thirteen, that is to say, cut-off took place at 
 about one-thirteenth of the stroke, and they made the 
 still greater mistake of passing the exhaust steam 
 from a cylinder expanding through such a range round 
 the cylinder jacket. It seems scarcely credible, but 
 it is true. The diagram (fig. 18)^ is from the engine. 
 It shows what an enormous quantity of steam will 
 pass into a cylinder when the cut-off is too early and 
 the heat of the cylinder not maintained by means of 
 a steam-jacket. The loss, however, in this instance 
 
 Fig. 18. 
 
 was aggravated by the exhaust jacket. For the sake 
 of getting at some information as to what was going 
 on in this cylinder, we have assumed that the total 
 clearance and port spaces amounted to 5 per cent. 
 of the volume of the cylinder. This adds to the 
 diagram the space included within the line B, D. 
 But, even with this 5 per cent, and the cut-off at a, 
 the hyperbolic curve for that volume of steam falls, 
 as shown by the dotted curve a 5, a long distance 
 below the actual indicator diagram, so that the whole 
 of the area E is more than can be accounted for by 
 
 * We are indebted to The Engineer for this diagram. 
 
WORK CONDENSATION 53 
 
 dry steam cut-off at the point a, even when 5 per 
 cent, clearance is added. This gives some idea of the 
 extent to which this maker turned their cylinder into 
 a condenser, but a better idea may be gained, when it 
 is pointed out that, in order to obtain the curve a e 
 of the indicator diagram, a further quantity of steam, 
 represented by the rectangle A, B, C, D, would be 
 necessary, and must have entered the cylinder, been 
 condensed, and re -evaporated. The engine in question 
 used 42 Ib. of water per brake horse-power per hour.* 5 
 
 The indicator diagram (fig. 18) shows a large amount 
 of initial condensation, owing to the cooling action of 
 the exhaust jacket. In fact, all the sources of loss 
 were brought into play in this instance of faulty 
 designing. We have inserted the diagram in this 
 place to show the folly of attempting to work with 
 such a great range of expansion without a proper 
 steam-jacket. 
 
 After Professor Eankine's clear statement respect- 
 ing work condensation, little more need be added. 
 We have here a species of liquefaction which cannot 
 be prevented, and the higher the efficiency of the 
 engine the greater the amount of work condensation: 
 but the water resulting from this liquefaction, if left 
 in the cylinder, is a source of waste ; some of it is 
 boiled away as expansion proceeds, and the rest is 
 sent to the condenser, or into the drain from the 
 exhaust pipe ; in any case this is a waste of heat. 
 Whereas, in a steam-jacketed cylinder, the jacket 
 steam prevents the condensation taking place in the 
 cylinder, the liquefaction taking place in the jacket, 
 where the hot water produces no harm but is returned 
 to the boiler to be re-evaporated to do more work. 
 
 We have gone more fully into initial condensation, 
 
 * The Engineer, 3rd August 1888. 
 
54 CYLINDER CONDENSATION 
 
 because it is a cylinder waste which is entirely pre- 
 ventable. Most of the cards illustrating initial losses 
 show the inevitable waste of attempting to work ex- 
 pansively in an unjacketed engine. " The hot water 
 of initial and work condensation must be got rid of 
 during each exhaust stroke ; such water, if allowed to 
 remain, not only makes the engine noisy, but it will 
 absorb an immense amount of potential heat from the 
 incoming steam in the next steam-stroke, and thus 
 the economic performance of the engine will be greatly 
 reduced."^ Work condensation always takes place, 
 and we need not further explain the waste attending 
 it, since a simple remedy in the steam-jacket is pro- 
 vided for removing the loss. 
 
 * Engines for Pumping, by the late Mr. W. E. Rich, 1884. 
 
CHAPTEE IV. 
 
 MEANS PEOPOSED FOR PREVENTING INTERNAL 
 CYLINDER CONDENSATION. 
 
 THE following methods have been proposed and tried 
 for reducing cylinder condensation : 
 
 (1) The use of superheated steam. 
 
 (2) Hot-air jackets. 
 
 (3) Hot-water jackets. 
 
 (4) Non-conducting cylinders. 
 
 (5) Turned and polished pistons and cylinder-covers. 
 
 (6) Steam-jackets. 
 
 1. Superheated steam is formed by imparting 
 further heat to ordinary or saturated steam. It is 
 also formed by the free expansion of saturated steam. 
 
 In practice, steam is superheated in its course from 
 the boiler to the cylinder by being made to pass 
 through tubes which are heated on one side by 
 the products of combustion on their way to the 
 chimney. 
 
 " Superheating conduces to economy, but the extent 
 to which it can be carried is practically limited to a 
 few degrees, owing to the injurious chemical action of 
 such steam upon the metal of the cylinder, and the 
 
56 INTERNAL CYLINDER CONDENSATION 
 
 excessive friction caused by the high temperature."* 
 The chief object of superheating, however, is not so 
 much to secure economy as to prevent one great cause 
 of inefficiency, viz., the use of wet steam. But high- 
 pressure steam cannot be sufficiently superheated to 
 thoroughly cure initial condensation. Mr. Holmes 
 " shows that superheating the boiler steam is im- 
 practicable for modern high-pressure engines, "t 
 
 When boilers are given to priming, some heat may 
 with advantage be added to the steam after it is formed, 
 so as to insure its being thoroughly dry before it enters 
 the cylinder. When low-pressure steam was used, 
 a moderate amount of superheating could be adopted 
 with advantage; but, even then, considerable risk 
 attended the use of the superheating apparatus. The 
 ordinary superheating apparatus is costly and cumber- 
 some, while the excessive wear and tear to which it is 
 subjected soon renders it useless. By the least amount 
 of neglect on the part of the engine-driver, the steam 
 may be so much overheated as to cause an enormous 
 amount of injury to the piston and cylinder. 
 
 Nevertheless, the use of superheated steam is 
 strongly advocated by some engineers ; consequently, 
 we occasionally hear of improved superheaters being 
 introduced. When experiments on the use of super- 
 heated steam had been carried out years ago, the 
 engines had not the excellent metallic packing J they 
 now have. Mr. Henry Davey recently said : If the 
 use of superheated steam were now to be reverted to, 
 he thought the difficulties would not again be met 
 with that had been experienced years ago, when it 
 was tried and discarded. There was a great deal to 
 
 * The Steam-Engine, Northcott. 
 t The Steam-Engine, Holmes, 1887. 
 
 J See Appendix for particulars of the United States Metallic Pack- 
 ing, as made at the Soho Engineering Works, Bradford. 
 
LOCOMOTIVE CYLINDERS 57 
 
 be done, he believed, in the direction of superheated 
 steam.^ 
 
 2. Hot-air jackets. Hot-air jackets are now very 
 rarely used. Many plans have been tried for heating 
 the cylinder in the flues of the boiler, &c., all of which 
 have failed. In portable engines, about thirty years 
 ago, the plan of placing the cylinder in the top of 
 the smoke-box was tried and abandoned for obvious 
 reasons. But, in the portable engines made by another 
 firm, the cylinders were similarly placed, and surrounded 
 by steam-jackets as well, which entirely removed all 
 inconveniences arising from the action of the hot 
 gases on the working steam. 
 
 Some years ago a writer in The Engineer proposed 
 to draw a moderate quantity of heated air into the 
 jackets of small portable engines by means of the ex- 
 haust steam, so as to effectually prevent condensation 
 in the cylinder.t In 1885 a patent was taken out, 
 among other things, for the employment of a steam 
 jet for drawing the hot gases through the cylinder- 
 jacket. In many locomotive engines the cylinders 
 are placed inside the smoke-box, but, as they are at 
 the bottom, they are not so likely to be overheated 
 by the hot gasses on their passage to the chimney. 
 A little time ago we saw a tandem compound traction 
 engine the low-pressure cylinder and valve chest of 
 which were placed in the base of the chimney, so that 
 the hot gases from the smoke-box could keep up the 
 heat of the working steam, but the usual injurious 
 effects were experienced, viz., destroyed lubrication : 
 consequently the plan was quickly abandoned. Mr. 
 
 * Messrs. M'Phail & Simpson's superheating apparatus has been 
 put to the test with the most satisfactory results as regards the 
 economy of steam and durability of the apparatus itself. See 
 Appendix for more information respecting this. 
 
 t The Engitieer, 13th May 1870. 
 
58 INTERNAL CYLINDER CONDENSATION 
 
 Northcott says : " There are practical difficulties in 
 using the hot gases in the jacket, chiefly arising from 
 their high temperature and from the deposit of soot 
 and tarry matter upon the surfaces of the jacket. 
 The former leads to excessive friction in the cylinder, 
 and the latter to the choking of the passages and the 
 non- transfer of heat."^ 
 
 3. Hot- water jackets. A few inventors have, 
 at intervals, proposed to jacket the cylinders with hot 
 water, but we are not aware that the plan has ever 
 been tried. A patent was taken out in 1831 for 
 supplying the jackets with a solution of potash and 
 water, kept heated. The use of many other fluids 
 has been suggested, which we cannot refer to here, 
 The Engineer proposes the use of hot water, as the 
 following extract shows : " It should be borne in 
 mind that the great source of waste of fuel is con- 
 densation within the cylinder ; and that it is only by 
 preventing this waste that any very marked advance 
 can be made on existing practice. If the jacket 
 could be kept hot by heat that would otherwise be 
 wasted, it would be a perfect remedy. We suggested 
 some years ago the use of hot water as the heating 
 medium, the water being raised to the necessary 
 temperature in the flues. For example, it is by no 
 means unusual to find the water in a Green's economizer 
 raised to a temperature of 340, while the maximum 
 temperature in the cylinder does not exceed 300, and 
 the average temperature is much less. Now, if the 
 feed-pump drew the water from the economisert and 
 forced it through the cylinder-jacket, and thence into 
 
 * The Theory and Action of the Steam-Engine, W. H. North cott. 
 
 t The saving of steam by the application of Green's econoniiser is 
 happily well known. It is interesting, however, to see this proposal 
 to render it still more valuable as a steam economiser. 
 
HOT-WATER JACKETS 59 
 
 the boiler, an excellent result would no doubt be 
 obtained. Again, if the jacket were traversed by the 
 water-coils of a Perkins' heating apparatus, while the 
 fire-coils were located in the boiler flues, a similar 
 result would be more simply attained. Various 
 methods of applying this principle will suggest them- 
 selves, the difficulties and objections which stand in 
 the way being very small." * A correspondent to 
 The Engineer, 27th August 1886, proposes another 
 method of jacketing with hot water, as under : " The 
 best system of jacketing that can be adopted is to 
 cast spiral ribs round the cylinder liner, and take 
 water in at one end and out at the other, the water 
 flowing round the cylinder and then through a system 
 of tubes heated by the waste heat from the boiler. 
 There would then be a constant circulation of hot 
 water maintained round the cylinder. A device so 
 cheap and simple would be sure to work well." We 
 have stated these proposals fully in the hope that 
 some one will put the system to a practical test, so as 
 to ascertain if it will more efficiently prevent the con- 
 densation of steam in the cylinders of steam-engines 
 than steam-jacketing does. 
 
 4. Non-conducting cylinders. It is a well- 
 known fact that much of the condensation of steam 
 that takes place in unjacketed cylinders is owing to 
 the cast-iron of which the cylinder, the piston, and lids 
 are made, being such a rapid conductor of heat. It 
 necessarily follows that, if a non-conducting material 
 could be used for this purpose, this evil would }& re- 
 moved. For instance, suppose the cylinder was made 
 of a non-conductor and non-absorber of heat, the 
 steam would not be robbed of its heat and condensed 
 on entering the cylinder, simply because the material 
 
 * The Engineer, 3rd January 1879. 
 
60 INTERNAL CYLINDER CONDENSATION 
 
 would not part with its heat when exposed to the 
 atmosphere during the exhaust. If it were possible 
 to construct a cylinder of such a character, then would 
 steam work with a maximum efficiency, and we should 
 have the nearest possible approach to a perfect steam- 
 engine. 
 
 Many methods have been proposed for the con- 
 struction of non-conducting steam-engine cylinders. 
 Some of these must be named presently. 
 
 But, to make this part of our subject as clear as 
 possible, we quote as under : " In order to avoid or 
 reduce condensation in steam cylinders, we must con- 
 struct them either of a material which will conduct 
 heat so slowly that only a small portion of its total 
 weight will alter in temperature ; or of a material 
 having so low a specific heat that any moderate 
 quantity of caloric will suffice to raise it through the 
 required range of temperature ; or, finally, of a 
 material which will combine both these characteristics. 
 Wood would satisfy the first condition very fairly, but 
 it is obviously inapplicable to the required purpose."^ 
 
 Watt used a wood cylinder, which no doubt answered 
 admirably for checking condensation of steam, but it 
 practically failed as a substitute for metal for the 
 construction of cylinders, as related in Chapter I. 
 
 It is suggested that a non-conducting cylinder 
 could be made of lignum-vitse in staves, powerfully 
 compressed, and forced into a heavy cast-iron case ; 
 the material would be found almost if not quite in- 
 susceptible of being injured by the steam. It is 
 suggested that, in case a wood-lined cylinder does not 
 succeed in practice, there could be no difficulty what- 
 ever in lining cylinder-lids and covering piston-faces 
 with wood ; and, considering the enormous area pre- 
 
 * The Engineer, 2nd June 1871. 
 
LEAD FACINGS 61 
 
 sented to the steam by these surfaces in short-stroke 
 engines of much power, it is evident the result would 
 be almost as good as though the entire cylinder were 
 composed of non-conducting materials.^ 
 
 Smeaton used wood-lined pistons and heads : we 
 fear, however, that Smeaton's device cannot be made 
 successful at modern temperatures and pressures. 
 
 A near approach to thermal neutrality might be 
 had in a cylinder consisting of an inner tube of very 
 thin steel and an outer casing of cast-iron, the space 
 between the two being filled up with compressed paper 
 or charcoal. The lids should be got up in the same 
 way.t A patent was taken out for the above plan 
 sixteen years after it was proposed in The Engineer. 
 The inventor says : " The internal surfaces are covered 
 with a layer of non-conducting composition, such as a 
 mixture of asbestos and cement ; the wearing surfaces 
 are covered with sheet steel. "J Lead has often been 
 proposed as a suitable material for covering the pistons 
 and cylinder-covers. The conductivity of lead is but 
 three-fourths that of cast-iron. Of course, a lead 
 cylinder cannot be used because it is too soft. In 
 order to use lead for the body of the cylinder, the 
 working surface should be composed of a thin steel 
 tube, placed in an outer casing of cast-iron, the space 
 between being filled up with lead run in and com- 
 pressed by hydraulic power. We believe that some 
 experiments were made with an engine having the 
 piston and lids covered with lead-plates, but some 
 difficulty was experienced, owing to the relative ex- 
 pansions of the two metals being so different. 
 
 " There does not appear, however, to be any obstacle 
 
 * The Engineer, 3rd January 1873. 
 
 f The Engineer, 8th July 1870. 
 
 J Patent No. 15390, 25th November 1886. 
 
62 INTERNAL CYLINDER CONDENSATION 
 
 in the way of using porcelain or slate for the intended 
 purpose : plates of the material about an inch thick 
 could easily be let into the cylinder lids and piston, 
 and secured by cement in seats cast for the purpose in 
 the metal. The experiment would be well worth trying. 
 Any expedient, in short, which holds out fair promise 
 of neutralizing the enormous condensing powers of the 
 piston-face and cover would be worth testing. To the 
 prevention of this condensation we can alone look for 
 further progress in the direction of economy."^ 
 
 At a meeting of the Institute of Mechanical Engineers, 
 a paper was some time ago read on triple-expansion 
 engines, when Professor Kennedy said : " If slag- 
 glass liners to the cylinders could be used, or if in 
 some other way we could make them non-conducting, 
 it would get rid of the present abomination of 
 sending in 20 per cent, of the steam as water, or 
 converting it into water as it entered the cylinder." 
 
 A few months ago M. Dwelshauvers Dery, Professor 
 of Applied Mechanics at the University of Liege, 
 published in the Revue des Sciences pures et appliquSes 
 a very interesting article on this subject, from which 
 we quote. The writer refers to the question recently 
 agitated by Mr. Thurston, the well-known American 
 scientist. 
 
 " The improvement consists in clothing with an in- 
 sulated heat-resisting covering, not the outside, but 
 the inside of the cylinders that is, the metallic 
 surface which is brought into direct contact with the 
 steam, in order to avoid the loss which is occasioned 
 by the direct contact between the iron and the steam. 
 
 " The economic principle is as follows : 
 
 "A steam-engine attains its maximum efficiency 
 when the whole of the heat given out by the steam 
 
 * The Engineer, 1st April 1881. 
 
MR. THURSTON'8 PROPOSALS 63 
 
 to the metallic walls during its admission is returned 
 by the walls during its expansion ; in other words, 
 when all the water arising from the condensation of 
 steam during admission is re-vaporized during expan- 
 sion, and the metal is dry on the inside from the 
 commencement of the exhaust. 
 
 " To carry out this principle to the greatest satisfac- 
 tion, the action of the walls is to be suppressed (taken 
 off), or, what is more exact in practice, the condensa- 
 tion should be reduced as much as possible by making 
 the cylinder of metal which is a bad conductor, and 
 which presents but feeble heat capacity. But, as this 
 metal does not exist, refuge must be found in a 
 superficial covering, which shall possess these qualities 
 and be durable likewise, and which shall cover the 
 whole of the surface that is brought into contact with 
 the steam. 
 
 " Mr. Thurston's proposed method of covering is as 
 follows : The surfaces to be covered are subjected 
 for several days to the action of diluted nitric acid. 
 Then a spongy substance is obtained, made probably 
 by a mixture of carbon and silicate, and treated with 
 insulating varnish. Layers of linseed oil, which 
 adhere solidly and fill up the pores, are spread all 
 over to complete the insulation. Experience has 
 shown that the economy will be considerable, even 
 with a coating far removed from the ideal. The 
 supplementary heat lost in the metal by the initial 
 condensation is diminished, and, at the same time, the 
 useful return during the expansion is increased, while 
 the saving in clear loss during exhaust is reduced. 
 
 "In 1866 Mr. Emery proposed porcelain. Mr. 
 Babcock has tried bismuth and other metals. Mr. 
 Thurston had his attention directed to the process he 
 suggests by the examination of corrosion in condensers 
 
64 INTERNAL CYLINDER CONDENSATION 
 
 and air-pumps, which corrosions are due in great 
 measure to the action of oily acids. Mr. Hill made 
 an analysis, and sought to convert the spongy mass 
 into an insulating substance. He has succeeded, aided 
 by Mr. Chamberlain, who has applied to the task all 
 the resources of experimental analysis, in order to 
 give it a solid base. 
 
 " In conclusion, an engine using steam sufficiently 
 superheated, with such a degree of expansion that 
 the metal will be dry at the end of the stroke, and 
 provided with an exterior protecting covering and 
 with an interior insulating layer, as advocated by Mr. 
 Thurston, will realise the most perfect type of steam- 
 engine possible."^ 
 
 We shall bring this part of the subject to a close 
 by referring to a series of interesting experiments 
 carried out by Mr. Emery with glass and iron cylinders. 
 
 Mr. Emery carried out 250 experiments, so that 
 the results arrived at must be reliable. He says : 
 " I constructed two cylinders of like dimensions, one 
 of glass, the other of iron, in such a manner that 
 either could be attached to a valve which regularly 
 admitted steam from a boiler to the cylinder, and per- 
 mitted its exhaust to enter into a condensing coil lying 
 in a tub of water. The capacity of the two cylinders 
 was made exactly the same, as shown by transferring 
 water from one to the other. When put in turn in 
 the condition of a steam-engine cylinder, the iron 
 cylinder used (averaging the experiments) fully twice as 
 much steam as the glass one, shown by the fact that 
 twice the quantity of water came through the condens- 
 ing coil for the same number of movements of the 
 valve. Steam of same pressure was used in both 
 cylinders, and the experiments were many times re- 
 
 * The Mechanical World, 15th April 1892. 
 
ME, CROLUS SUGGESTIONS 65 
 
 peated, with the same results. The glass cylinder 
 saved half the steam." 
 
 We think it is a great pity that some of the simple 
 methods of coating the cylinder-lids and piston with 
 non-conducting materials have not been thoroughly 
 tried ; pottery, slate, or glass appear to be very suitable, 
 because, in addition to their being bad conductors of 
 heat, they are capable of presenting a smooth surface. 
 It is a well-known fact that the cylinder-covers and 
 piston-faces are invariably rough, and these rough 
 castings just cooled by the exhaust steam form a 
 perfect condenser : the rougher the surface the greater 
 the condensation. If pottery ware cannot be tried,- 
 there is no valid reason why smooth steel- plates should 
 not be secured to the lids and piston with a thickness 
 of slag- wool, or some other non-conductor between 
 the steel plates and the castings. 
 
 5. Polished piston and cylinder-covers. A 
 most useful and interesting paper was recently read 
 by Mr. Croll before the Institute of Naval Architects, 
 in which some simple methods for preventing initial 
 condensation in triple-expansion engines are recorded ; 
 and as this is so closely connected with this part of 
 our subject, we shall devote some space to Mr. Croll's 
 sensible suggestions. He says : " Supposing a piston 
 to begin its stroke with a temperature lower than the 
 steam entering, it is evident that the steam will first 
 heat both the piston and cover faces, and, in doing so, 
 deposits a film of water upon them. After the steam 
 is cut off and the pressure lowered, the deposited 
 water will partly become steam again ; but then the 
 exhaust is opened and the pressure still further 
 lowered: the remainder will evaporate much more 
 rapidly, and, in doing so, cool the piston cover and 
 cylinder walls, so that with the following stroke the 
 
66 INTERNAL CYLINDER CONDENSATION 
 
 cycle is again repeated.^ In a low-pressure cylinder 
 of a modern marine engine, when the diameter is one 
 and a half times the stroke, we find the exposed 
 surface of piston and cover is 50 per cent, greater 
 than that of the working surfaces of the barrel, and it 
 is to the former that I wish to direct your attention. 
 The greater the re-evaporative power of the material 
 in contact with the steam the greater will be the 
 cooling of the surfaces, and the greater the initial con- 
 densation ; the re-evaporative power of a body is in- 
 creased by an increase of surface : a fairly smooth 
 surface may, nevertheless, have a much greater area 
 exposed than the geometrical plane which it is taken 
 to represent. The total condensation in a steam-engine 
 is a question of very thin films of water, and the 
 structure of the surfaces exposed to the steam merits 
 our closest attention." 
 
 As far as can be seen from Mr. Croll's experiments, 
 a polished surface is far superior to that of ordinary 
 cast-iron as it comes from the mould, and a rough 
 steel casting is about the worst material that could 
 be chosen; it appears therefore advisable to carefully 
 turn and polish, as far as possible, all the parts of the 
 steam cylinder which come in contact with steam 
 performing work. Mr. Croll's paper concludes as 
 under : 
 
 " 1. I made a disconnecting paddle-engine, in which 
 each wheel could be driven by a perfectly independent 
 compound engine ; in the starboard engine all the 
 parts were turned and polished ; in the port engine 
 all the parts exposed to the steam were left rough. 
 The port engine was troubled with water ; the starboard 
 engine was apparently dry. 
 
 * The laws of condensation and evaporation are so clearly stated 
 that we insert them here in connection with the remedy. 
 
TORPEDO BOAT ENGINES 67 
 
 "2. In my experience, excessive condensation has 
 always occurred in connection with rough steel pistons 
 and covers ; in one case this was so marked that the 
 top of the piston would not give a card at all, which 
 I attributed to the cover being of rough cast-steel 
 and combining with the top of the piston to absorb 
 the heat of the steam. 
 
 " 3. Torpedo boat engines that have turned and 
 polished pistons, and, in some cases, polished covers, 
 are quite remarkable for the economy of steam at 
 nearly all powers ; and, at all events, are very free 
 from water in the cylinders. 
 
 " 4. The highest results known to me are obtained 
 by the land engines made by Messrs. Sulzer : the piston 
 and covers are turned, the consumption of steam, 
 11*73 Ibs. per indicated horse-power per hour, has 
 been obtained in the vertical triple-expansion engines. 
 If we wish to make machinery which will give the 
 highest results in economy, we must turn and polish 
 the surfaces of the piston and covers, or seek a 
 method of coating them over with a metallic layer 
 which will diminish their tendency to absorb and 
 reject heat." 
 
 Several other means have been proposed and tried 
 for diminishing the liquefaction of steam in unjacketed 
 cylinders beside the five plans we have adverted to. 
 
 It may be useful if we refer to these, and afterwards 
 pass on to deal with the steam-jacket, the only suc- 
 cessful means at present devised for reducing internal 
 condensation in steam-engine cylinders. 
 
 Many patents have been taken out for circulating 
 heated oils and other substances that melt without 
 being converted into vapour round the working barrel 
 of the cylinder. 
 
 It has been suggested to prevent cylinder condensa- 
 
68 INTERNAL CYLINDER CONDENSATION 
 
 tion by the use of air expanded by beat combined 
 with the working steam. Steam is condensed and 
 loses its pressure with frightful rapidity when in con- 
 tact with a cold surface ; whereas air under the same 
 circumstances parts with its heat with extreme 
 sluggishness as compared with steam. There are 
 many difficulties to be surmounted before engines 
 using heated air or air combined with steam can suc- 
 cessfully compete with the steam-engine. At the 
 present time very little is heard of some of the 
 schemes for using air and steam combined that were 
 to the front a few years ago. Some time since, a 
 piston was introduced by Mr. T. Sturgeon. The 
 object in view was to jacket the piston and also use 
 it as a heater to raise the temperature of the cylinder : 
 the steam was admitted into the piston through holes 
 in the top and drained by means of cocks. This 
 body of live steam, carried along between the walls 
 of the piston, and in direct contact with the inner 
 surface of the cylinder, would, it was urged by the 
 inventor, heat the cylinder far more effectively than 
 the external jacket could do, and would also present a 
 hot surface of the piston to the steam, while the exhaust 
 was not interfered with or acted upon by the hot 
 steam except the part immediately in front of the 
 piston. In compound engines it is recommended 
 that, in addition to the jacketed pistons, an external 
 steam-jacket should be applied to the high-pressure 
 cylinder. 
 
 The losses arising from initial condensation may be 
 reduced by compression. The closing of the exhaust 
 port before the end of the stroke, and the consequent 
 compression of the steam then remaining in the 
 cylinder, has a useful effect on the working of an 
 engine by providing an elastic cushion at the end of 
 
MESSRS. ROBE Y J 8 CYLINDER SECTION 69 
 
 Fig. 19. Separate steam and exliaiist ports good cylinder drainage. 
 
70 IXTERNAL CYLINDER CONDENSATION 
 
 the stroke, which secures smooth running at high 
 speeds. " In quick-speed engines the imprisoned 
 steam may advantageously be compressed up to the 
 initial pressure." * Experiments have been made, 
 and the results have shown a gain in economy by 
 increasing the compression which has the effect of 
 heating the cylinder- cover and piston, and preventing 
 condensation of steam on admission. 
 
 It has been said that the jackets around the body 
 of the cylinder are of no use without compression, and 
 the greater the compression the greater the economy 
 secured by the employment of steam-jackets. 
 
 A high piston speed has the effect of reducing the 
 cylinder condensation by lessening the time allowed 
 for the transfer of heat. 
 
 The Steam-Jacket. 
 
 6. Steam- Jackets. The last method, and the 
 most successful means at present employed for reducing 
 the condensation of steam within the cylinders of 
 steam-engines, must now be dealt with. 
 
 It is somewhat remarkable that, in spite of our 
 increased knowledge of the laws of heat, coupled with 
 the fact that the steam-jacket has been in use more 
 than a century, there are many engineers to-day who 
 do not understand its function. Some of these makers 
 have applied the steam-jacket for years on the engines 
 they manufacture, and they will tell you that its use 
 conduces to economy. But ask them to explain the 
 action : they will inform you that the jacket round the 
 cylinder reduces condensation, and the consequent 
 waste of fuel, by preventing the radiation of heat from 
 the working steam. These people " share in the 
 
 * The Theory and Action of the Steam-Engine, Northcott. 
 
WATT AND TREDGOLD 71 
 
 mistake of the greatest writer that probably we have 
 ever had upon the steam-engine (we allude to Tred- 
 gold), who, clear as he was in almost every point con- 
 nected with that subject, was, in respect of this parti- 
 cular of steam-jacketing, in error, and was led from that 
 error to condemn Watt's practice of the steam-jacket 
 as a mistake. For Tredgold, not appreciating the 
 theory of the steam-jacket, held, that it was a mere 
 contrivance for keeping the cylinder warm ; and that, 
 although it did this, it did it by the waste of more 
 steam than would have been wasted in the unjacketed 
 cylinders ; the excess being (in Tredgold's judgment) 
 that due to the extra size of the jacket over and 
 above that of the cylinder which it enveloped."^ It 
 is owing to this incorrect notion of the theory of the 
 jacket being abroad that some engineers (who do not 
 jacket their cylinders) give as their reason the hack- 
 neyed phrase that the loss from radiation may 
 just as well come from the steam in the cylinder as 
 from the steam in the jacket ; whereas, the loss in 
 unjacketed cylinders arising from condensation is 
 not measured by the radiation at all, but is a much 
 greater loss, as we have already explained in the 
 previous chapters, t 
 
 The true function of the steam-jacket appears to 
 be: 
 
 (1) To keep the cylinder barrel and covers hot, so 
 as to prevent the alternate heating and cooling of the 
 metal of the cylinder. The steam enters a cylinder 
 
 * Report on the Trials of Traction Engines at Wolverhampton, by 
 Sir F. J. Bramwell and James Easton. 
 
 f Some little time ago a well-known engine-maker was asked if the 
 cylinder of a steam-engine we were looking at was steam-jacketed. 
 He, placing his hand on the cylinder lagging of the working engine, 
 said : " There is no need for a steam-jacket as the loss of heat is very 
 slight." 
 
72 INTERNAL CYLINDER CONDENSATION 
 
 as hot as itself : there is then no initial con- 
 densation. 
 
 (2) To prevent the liquefaction of steam within 
 the cylinder, resulting from the performance of work, 
 this condensation is transferred to the steam in the 
 jacket where the presence of hot water produces no 
 bad effect, but is returned to the boiler. 
 
 (3) To prevent the loss of heat during the exhaust, 
 the cylinder liner being hot and dry, very little heat 
 is transmitted to the atmosphere or to the condenser, 
 as fully explained later on. 
 
 The steam-jacket conduces to economy by permit- 
 ting higher grades of expansion to be used with 
 economy. We have already shown that the greater 
 the range of expansion the greater the loss without 
 the steam-jacket. 
 
 Let us now more fully, and as clearly as possible, 
 explain the action of the steam-jacket. By its means 
 the cylinder is constantly kept at the same tempera- 
 ture as the steam within the boiler : the sides and 
 ends of the cylinder being hot and dry, no steam will 
 be condensed during the admission ; therefore the 
 initial pressure will, as nearly as possible, coincide 
 with the full boiler pressure. No steam having been 
 condensed during admission, it follows that no. water 
 will have to be evaporated arising from this cause ; 
 hence the enormous loss of heat produced by this 
 boiling process will be entirely prevented. During 
 expansion, the sides of the cylinder being hotter than 
 the working steam, the latter is slightly superheated ; 
 hence no condensation can take place within the 
 cylinder during expansion. Again, the sides of the 
 cylinder being hot and dry, it follows that very little 
 heat will be lost during the exhaust, because it is a 
 well-known fact that dry cast-iron parts with its 
 
WORK CONDENSATION 73 
 
 heat very slowly, compared with the same surface 
 covered with damp steam, and what little heat is 
 transmitted from the metal during this exposure to 
 the atmosphere or condenser, as the case may be, is 
 quickly repaid by the jacket causing a slight condensa- 
 tion in the steam-jacket. Mr. Northeott says : 
 " Heat passes from the jacket to the expanding steam, 
 sufficient in many cases to keep the steam in the 
 saturated state throughout the stroke." 
 
 To prevent the liquefaction of any steam within 
 the cylinder resulting from the performance of work, 
 we must impart as much heat to the steam as it loses 
 in performing its task ; and this is precisely what the 
 jacket does. The whole theory of its action may be 
 summed up in the following words, quoted from The 
 Engineer : " All the liquefaction due to the perform- 
 ance of work by the steam within the cylinder is 
 transferred to the steam within the jacket. The 
 water resulting from this liquefaction is restored to 
 the boiler, where it is re-evaporated, and flows to the 
 cylinder to do more work ; whereas, if the liquefac- 
 tion had taken place within the cylinder, the resulting 
 water would have been re-evaporated there instead of 
 within the boiler, and the resulting steam, although 
 obtained at just the same expenditure of power, would, 
 instead of doing work on the piston, do it in heating 
 the condensing water. It thus appears that, in a 
 properly jacketed engine, the true seat of the entire 
 energy of the engine is in the jacket, and not in the 
 cylinder ; and, startling as the statement may appear 
 at first sight, it is none the less virtually true, that it 
 is in the jacket, and not in the cylinder, that all the 
 work of the steam is performed. It follows, as a con- 
 sequence, that the condensation which takes place in 
 the jacket does not in any way represent loss of fuel, 
 
 ~ 
 
 OF THE 
 
 'UNIVERSITY 
 
74 INTERNAL CYLINDER CONDENSATION 
 
 except in so far as that condensation is a result of 
 radiation and conduction through the sides of the 
 cylinder to the condenser during the time the exhaust 
 port is open, and of radiation to the external atmos- 
 phere."* 
 
 But we have shown that the loss from radiation 
 from the outside of the cylinder may be entirely pre- 
 vented by proper clothing, and that very little heat 
 will be wasted by conduction from the jacket to the 
 atmosphere or the condenser during the exhaust, seeing 
 that the sides of the cylinder will always be dry. We 
 may, therefore, safely infer that most of the condensed 
 steam collected from a properly-applied, perfectly - 
 clothed, and well-drained steam-jacket will be the 
 result of work condensation. We are sorry to con- 
 fess, however, in every-day practice, there are few 
 cylinders arranged so as to reap the full benefits of 
 thorough steam-jacketing. In another part of the 
 book we have named some of the requirements for 
 obtaining the best results. But, in passing, we may 
 point out some of the causes of the enormous losses 
 that take place in so-called jacketed cylinders. In 
 such engines it is impossible for the steam-jacket to 
 effect the saving in steam that we have assumed 
 should be saved. 
 
 " In most cases met with in practice, the barrels 
 only of engine cylinders are jacketed ; but, at the 
 moment of admission, or even at the point of cut-off 
 with high rates of expansion, a very small proportionate 
 part of the hot jacket is exposed to the steam/'t 
 and it is impossible for such a jacket to prevent the 
 initial condensation of the steam. In many engines 
 tested, this and other evils are allowed to pass, account- 
 
 * The Engineer, 17th November 1871. 
 
 t The Theory and Action of the Steam- Engine, Northcott. 
 
STEAM SEPARATOR REQUIRED 75 
 
 ing for the enormous amount of condensation frequently 
 met with. We have heard of some experiments with 
 triple-expansion engines where the losses from internal 
 condensation amounted to 25 to 30 per cent. * There 
 are other engines of the same type so well cared for 
 by the designer that the loss from condensation only 
 amounted to 5 to 6 per cent. 
 
 To prevent the losses named above, the cylinder 
 liners should be thoroughly enveloped in a large body 
 of steam (see fig. 50). 
 
 The steam ports should be short and heated : 
 better still if separate steam and exhaust ports are 
 provided. The clearance should be reduced to 
 the utmost limit. The covers and pistons must be 
 smooth, and carried out in accordance with Mr. Croll's 
 directions. 
 
 In short-stroke engines of large diameter the pistons 
 must be heated. 
 
 The working steam should be perfectly dry. A 
 good separator should be applied to remove all water 
 from the working steam. The presence of water in 
 any quantity in steam appears to take all the life 
 out of it. 
 
 " The admission of wet steam into a steam-jacketed 
 cylinder is also productive of great loss, owing to the 
 evaporation of the contained water during the stroke 
 by heat abstracted from the jacket." t 
 
 In many cases the jackets may be supplied with 
 steam of a higher pressure than the steam employed 
 in the cylinder. It has been proved by practical 
 experience that the greatest attainable economy has 
 been secured by this arrangement of steam-jacketing. 
 
 It must be clearly understood that it is only by 
 
 * In Chapter III. larger losses are referred to. 
 
 t The Theory and Action of the Steam-Engine, Northcott. 
 
76 IN TEEN AL CYLINDER CONDENSATION 
 
 thorough steam-jacketing that the beneficial results we 
 have stated can be realised. If the rules we have 
 laid down in other parts of the work were carefully 
 observed, the steam-jackets would in every case yield 
 an ample amount of economy of steam to well repay 
 for the trouble taken. Perhaps we have had, thus 
 far, too much theorising respecting the steam-jacket. 
 Our only course to get at the real value of jacketing 
 is by means of reliable tests. Surely the accurate 
 trials, carried out under the direction of the Institute 
 of Mechanical Engineers, should be sufficient to con- 
 vince every one of the economical value of the steam- 
 jacket. The most economical engines are always pro- 
 vided with real steam-jackets. Sulzer's vertical 
 triple-expansion engine is an example, as given further 
 on in this chapter. In 1890 Professor Unwin said r 
 " that a steam jacket was always, in every case, 
 useful. He had taken the trouble to go through fifty 
 experiments of a parallel character, with and without 
 the jackets, and in only one case did he find that 
 there was not a very distinct economy gained by the 
 use of the jacket, and that he attributed rather to an 
 experimental error.'' : 
 
 Mr. Cowper says : " A little experiment, which I 
 made many years ago, gave a very palpable demonstra- 
 tion of the action of the steam in a cylinder which 
 was not steam-jacketed. 
 
 " A glass tube, closed at the outer end, was fixed to 
 a cylinder, so as to form part of it. At the com- 
 mencement of each stroke the incoming steam con- 
 densed upon the interior surface of the glass tube, 
 forming a dew or film of moisture, visible from the 
 
 * Lecture on the Objects and Methods of Steam-Engine Trials, 
 delivered before the London Association of Foreman Engineers, March 
 1890. 
 
GLASS TUBE EXPERIMENTS 77 
 
 outside, which remained throughout the first part of 
 the stroke ; during the latter part of the stroke, when 
 the steam had been cut off and was expanding, and 
 consequently falling in temperature, the dew disappeared 
 by re-evaporation. 
 
 " The glass was then heated from the outside by 
 means of hot coals, and, as long as the external heat 
 was maintained, no condensation took place. Thus 
 the walls of an uiijacketed cylinder being at an inter- 
 mediate temperature between that of the incoming 
 steam and that of the exhaust, condense a portion of 
 the steam whilst the latter is at its full pressure, 
 sacrificing the power which should have been given 
 by the steam so condensed ; and when the re-evapora- 
 tion from the surface takes place, through the natural 
 reduction of temperature of the expanding steam below 
 that of the walls, the piston is approaching the end of 
 the stroke. In the case of a steam-jacketed cylinder, 
 not only is radiation from the outer surface of the 
 walls prevented, but heat is continually supplied at 
 the full temperature to the outer surface, to be con- 
 veyed by conduction through the metal to the inner 
 surface. The walls thus heated from the outside cause 
 no condensation of the incoming steam ; and, whilst 
 the steam is expanding, its pressure is kept up some- 
 what above the natural curve by the slight superheat- 
 ing and drying action of the hot walls." ^ 
 
 " We know now that we cannot work with the 
 expansive engines to any good purpose without a 
 steam-jacket."t 
 
 The effect of the steam-jacket on the indicator 
 diagram is very manifest. Fig. 20 represents a 
 beautiful card taken from a steam-jacketed Corliss 
 
 * The Steam-Engine, by the late E. A. Cowper, Esq., 3884. 
 t Sir F. J. Bramwell, Bart. 
 
78 
 
 INTERNAL CYLINDER CONDENSATION 
 
 engine: the initial pressure shown on 
 the diagram is within half a pound of 
 the boiler pressure ; the cut-off is 
 one-thirteenth of the stroke. This 
 diagram shows a perfection of valve 
 arrangement, valve setting, and general 
 efficiency, which it would be difficult 
 to equal.^ The expansion curve coin- 
 cides very nearly with the theoretical 
 curve : this being so, the diagram 
 shows little evidence of internal con- 
 densation : this result is brought about 
 by the cylinder ends and body being 
 thoroughly enveloped in steam of the 
 full boiler pressure. We may point 
 out also that the boilers supplying the 
 engine are noted for producing dry 
 steam. 
 
 Fig. 21 shows a pair of figures from 
 a Woolf beam rotative pumping-engme, 
 during a trial conducted by Mr. John 
 Taylor, M.Inst.C.E. ; the cylinders were 
 steam-jacketed, and the steam-main 
 thoroughly drained. 
 
 Fig. 22 shows a pair of 
 figures from the same engines, 
 on another trial, when the 
 jackets were shut off, and 
 the steam-main not 
 thoroughly drained. 
 The indicated 
 horse-power 
 
 * The Engineers I 3 3 
 
 Practical Guide, 
 J. Hopkinson. 
 
 Fig. 20. 
 
WOOLF ENGINE DIAGRAMS 
 
 79 
 
 shown in the two cases is almost identical, and the 
 initial pressure of steam nearly the same ; but the 
 great loss, arising chiefly from the want of steam- 
 jackets, is shown by the smaller rate of expansion in 
 the second case, viz., 9'3, as compared with 1576 times. * 
 
 Fig. 21. 
 
 Fig. 23 shows a Rankinised diagram taken from a 
 large side-by-side compound engine. The steam passes 
 from the high-pressure cylinder through a steam- 
 jacketed receiver: both cylinders are steam-jacketed. 
 
 Fig. 22. 
 
 It will be seen that the shaded portion, representing 
 the loss of power as against the theoretically attain- 
 
 * The Steam-Engine, by the late E. A. Cowper : a lecture 
 delivered at the Inst. of Civil Engineers in 1884. 
 
80 
 
 INTERNAL CYLINDER CONDENSATION 
 
 able maximum, is unusually small, showing that a 
 very high efficiency has been attained.^ We now 
 must refer to an interesting trial, carried out by Pro- 
 fessor Goodman and Mr. W. Hartnell, of a triple- 
 expansion engine, made by Messrs. J. & H. M'Laren, 
 Leeds. 
 
 Fig. 24 shows the combination of three cards and 
 their relation to the theoretical curve, which is shown 
 by the dotted curved line. The high-pressure clear- 
 
 ance is shown at A, the intermediate-pressure clearance 
 at B, and the low-pressure clearance at C. 
 
 The results obtained are so good that we give some 
 of the figures. 
 
 The engines were of the vertical inverted cylin- 
 der pattern, marine style, surface-condensing, with 
 cylinders 9 inches, 14J inches, and 22 J inches 
 diameter by 2 feet stroke, working down on a three- 
 * The Mechanical World, 9th March 1889. 
 
MESSRS. M'LAREN'S ENGINE 
 
 81 
 
 throw crank set at angles of 120 degrees. The 
 high-pressure and intermediate cylinders are jacketed 
 with live steam supplied direct from the main stearn- 
 
 X 3 | 1 3 1 I 
 
 pipe. The condensed water from the jackets is 
 allowed to escape through efficient patent steam- 
 traps. 
 
82 
 
 INTERNAL CYLINDER CONDENSATION 
 
 TABLE VI. Trial of a Triple Expansion Engine, 
 made "by Messrs. J. & H. M'Laren. 
 
 Duration of trial, . . . 4*1 hours 
 
 Indicated horse-power, . . 121 '85 I.H.P. 
 
 Brake horse-power, . . 106*9 
 
 Steam press in boiler absolute, . 1 7 1 '2 Ibs. per 
 
 sq. in. 
 
 Vacuum in condenser, . . 28 inches. 
 
 Feed-water used per indicated 
 horse-power per hour, includ- 
 ing jackets, . . . 13*6 Ibs. 
 
 Feed-water used per brake 
 
 horse-power per hour, . . 15 '5 Ibs. 
 
 Steam used in jackets per 
 indicated horse - power per 
 hour, . . . . 1'24 Ibs. 
 
 Coal burnt per indicated horse- 
 power per hour, . . . 1*35 Ibs. 
 
 Water evaporated per Ib. of 
 coal from a mean temp, of 
 110 F., . . . 10-11 Ibs. 
 
 Water evaporated per Ib. of 
 
 coal from and at 212 F., . 11 '34 Ibs. 
 
 Indicator gear was fixed on each cylinder, but, 
 instead of one indicator being fixed at each end of 
 each cylinder, only three instruments in all were 
 used, viz., one on each cylinder. T pipes were used, 
 one branch being carried to the top and the other to 
 the bottom, the indicator being fixed in the centre. 
 This was very unfortunate, as a considerable loss of 
 indicated power was thus sustained. It has been 
 found by actual experiment that this arrangement 
 may involve a loss of as much as 8 per cent., as com- 
 pared with having the indicators close up to their 
 work at each end of the cylinder. The boilers are of 
 the multitubular type. The whole was covered in to 
 
MESSRS. M'LAREN'S ENGINE 83 
 
 prevent, as far as possible, any loss of heat by radia- 
 tion. As the results obtained in previous trials with 
 the same engine were so exceptionally good, it was 
 determined to ask Professor Goodman of the York- 
 shire College, and Mr. Wilson Hartnell of Leeds, to 
 run an independent test, so that the figures published 
 might be accepted as above suspicion. 
 
 Eeferring once more to the diagrams (fig. 24), the 
 influence of the jacket is shown very clearly in this 
 diagram, for, while the actual line almost coincides 
 with the theoretical line in the case of the jacketed 
 cylinders, it falls considerably short of it in the case 
 of the low-pressure cylinder, which was not jacketed 
 at alL* 
 
 We now refer to some trials of a triple-expansion 
 condensing mill engine of the inverted type, made by 
 Messrs. Sulzer Bros, of Winterthur. We cannot do 
 better than quote some particulars of the tests from 
 The Mechanical World for 27th April 1894. This 
 engine is a thoroughly steam-jacketed engine, having, in 
 addition to other refinements for economising steam, 
 the piston and cylinder covers turned and polished, as 
 cited by Mr. Croll in previous pages of this chapter. 
 
 " The exceptionally high economy of this engine 
 will doubtless lead some of our engine-builders to dis- 
 pute the accuracy of the trials included in the descrip- 
 tion ; but, before doing so, it may be well that they 
 should know that the trials referred to were not made 
 by the engine-builders, but on behalf of the owners, 
 who naturally desired independent evidence that the 
 conditions of the contract had been fulfilled. Further, 
 the engine was tested under practically every-day 
 
 * " The Economical Use of Steam in Colliery Engines," a paper read 
 before the Federated Inst. of Mining Engineers by Mr. John M'Laren, 
 28th May 1891. 
 
84 INTERNAL CYLINDER CONDENSATION 
 
 conditions of work, and after it had been running for 
 some considerable time. The results obtained are, as 
 far as we are aware, the best yet placed to the credit 
 of any mill engine ; but, if certain theories are correct, 
 we ought to be able to improve upon this performance 
 by adopting the Corliss cylinder with sensibly less 
 clearance spaces than is possible with double-beat 
 valves." * 
 
 This engine has, in spite of the double-beat valves, 
 with the increased clearance and a moderate steam 
 pressure, achieved results which out-distance any 
 trustworthy records of the best horizontal Corliss mill 
 engines yet published. No steam separators were 
 used, but we should imagine that the steam must 
 have been dry. " The mechanical efficiency of large 
 compound-condensing and triple-expansion engines is 
 seldom more than 85 or 88 per cent, but in this case 
 an efficiency of 9245 is obtained." t 
 
 "According to the contract, the engine was not 
 to require more than 12*125 Ibs. of steam per 
 indicated horse-power per hour when developing 
 1100 indicated horse-power, it being understood that 
 the water condensed in the steam-pipes was to be 
 deducted, but not the water condensed in the jackets. 
 
 " From the above trials it is seen that, .with the 
 engine loaded to 1228'51 indicated horse-power 
 (nearly the maximum load), the steam used per hour 
 is only 1T94 Ibs. With the engine loaded 11387 and 
 11637, or a mean of 1151, and nearer to the normal 
 power, the mean steam consumption is 11'74 Ibs. 
 
 " The feed- water was measured in standard barrels 
 
 and fed to the boilers by a separate steam-pump. 
 
 The economiser was disconnected during the trials. 
 
 The steam pressure during the trials was almost 
 
 *, The Mechanical World, 27th April 1894. f find. 
 
MESSRS. SULZERS ENGINE 
 
 85 
 
 uniformly 151 Ibs. per square inch, and the initial 
 pressure in the high-pressure cylinder 147 to 150 Ibs., 
 so that the loss of pressure is very small. The 
 mechanical efficiency of the engine was 92'45 per 
 cent., the makers guaranteeing 92 per cent. Steam 
 is furnished by three Babcock and Wilcox water-tube 
 boilers. 
 
 " In December 1893, a set of three trials were made 
 to determine the economy of the engine. The follow- 
 ing is an abstract of the report : 
 
 TABLE VII. 
 
 DATE OF TKIAL. 
 
 Dec. 2. 
 
 Dec. 5. 
 
 Dec. 6. 
 
 Duration of trial hours, 
 
 47 
 
 5-15 
 
 5-033 
 
 Mean number of revolutions 
 
 
 
 
 per minute, 
 
 76-31 
 
 75-9 
 
 76-0 
 
 Mean pressure in high-pressure 
 
 
 
 
 cylinder Ib. per sq. inch, 
 
 48-48 
 
 47-309 
 
 46-57 
 
 Mean pressure in intermediate 
 
 
 
 
 cylinder, .... 
 
 14-84 
 
 13-48 
 
 14-12 
 
 Mean pressure in low-pressure 
 
 
 
 
 cylinder, .... 
 
 9-37 
 
 8'48 
 
 8-82 
 
 Indicated horse - power 
 
 
 
 
 high-pressure cylinder, 
 
 450-11 
 
 436-88 
 
 430-63 
 
 Indicated horse - power 
 
 
 
 
 intermediate cylinder, 
 Indicated horse-power low- 
 
 320-36 
 
 289-48 
 
 30374 
 
 pressure cylinder, 
 
 458-04 
 
 412-34 
 
 429-34 
 
 Total indicated horse-power of 
 
 
 
 
 engine, .... 
 
 1228-51 
 
 113870 
 
 1163-71 
 
 Feed-water consumed total 
 
 
 
 
 Ib 
 
 69 445-5 
 
 69,445-5 
 
 69,445-5 
 
 Condensed water from steam 
 
 
 
 
 pipe, .... 
 
 573-1 
 
 G23-9 
 
 610-6 
 
 Total net steam consumption, 
 
 68,872-4 
 
 68,821-6 
 
 68,834-9 
 
 Steam consumption per hour, 
 
 14,654-1 
 
 13,363-2 
 
 13,676-3 
 
 Steam consumption per indi- 
 cated horse-power per hour, 
 
 11-94 
 
 11-735 
 
 11-75 
 
86 INTERNAL CYLINDER CONDENSATION 
 
 "To compare these results with the best results 
 obtained here, some allowance has to be made for the 
 slightly different values of the horse-power in the two 
 countries. But, even with this deduction, the steam 
 consumption is only 11 '9 Ibs. per indicated horse-power 
 per hour probably the best result yet obtained from 
 a mill engine."^ 
 
 It is very evident that these excellent results were 
 due to the following, among other reasons : 
 
 (1) All three cylinders were thoroughly enveloped 
 in high-pressure steam, the barrels and ends are well 
 steam-jacketed and lagged. (2) The steam-jackets 
 and cylinders are well drained. (3) The inside of 
 the cylinder-lids and both faces of the pistons are 
 smooth, as already noted. (4) The admission of 
 steam into the cylinder is regulated automatically by 
 an excellent governor arrangement and valve gear, 
 which varies the cut-off to suit the load. (5) The 
 lubrication of the cylinders and all the working parts 
 has been most efficiently carried out. (6) General 
 excellence of the design ; and (7), The steam used was 
 undoubtedly dry. 
 
 Messrs. Sulzer Bros, have long been known as 
 builders of high-class economical engines, and the 
 table and particulars which we have been enabled to 
 place before our readers are well calculated to sustain 
 the high reputation which they so deservedly enjoy. 
 
 In a valuable paper on " The most Economical 
 Temperature for Steam-Engine Cylinders," by Mr. 
 Bryan Donkin, the following remarks occur, which 
 are well worthy of careful note : 
 
 " If engineers and others using steam-engines wish 
 to work economically and with smaller boilers, they 
 must arrange to keep their cylinders and covers as 
 * The Mechanical Wvrld, 27th April 1894. 
 
MR. BRYAN DONKIWS REMARKS 87 
 
 hot as the entering steam ; otherwise the cylinder 
 becomes unintentionally an efficient condenser, with 
 a large area of cooling surface. Properly applied, 
 steam-jackets are economical, because they raise the 
 temperature of the walls touched by the steam. Those 
 who cannot steam-jacket the whole cylinder should 
 at least jacket the two covers, which are the most 
 important surfaces. Well-arranged jackets, with pro- 
 perly sized pipes for entering steam and exit water, 
 without places for air to collect, are an excellent 
 investment, and pay a good interest on the small 
 additional cost." 
 
CHAPTEE V. 
 
 THE ABUSE OF THE STEAM-JACKET. 
 Faulty Designing. 
 
 " The steam-jacket to a cylinder is a static economises It has 
 no working parts, does not move, and, if property made at 
 first, will never cost one farthing for repairs or renewal." 
 
 THE steam-jacket, when properly designed and applied, 
 is of undoubted benefit in promoting the economy of 
 steam. Yet, owing to various causes which we shall 
 presently name, it is in a great many cases rendered 
 not only ineffective but positively detrimental. 
 
 Mr. Northcott says : " The steam-jacket may be 
 quite ineffectual or somewhat worse than ineffectual, 
 if without the means of removing air and water 
 from it." 
 
 Mr. Holmes says : " Many cases have occurred in 
 practical experience in which jacketing has been carried 
 out so as to be positively injurious instead of bene- 
 ficial." It will serve no good purpose to close our eyes 
 to the fact that there must be many engineers at the 
 present time who entertain mistaken notions respect- 
 ing the function of the steam-jacket, to account for 
 the number of modern steam-engines now being turned 
 out from English, American, and Continental works, 
 fitted with jackets, which, to say the least, are of 
 
CURIOUS NOTIONS ON JACKETING 89 
 
 doubtful advantage, owing to faulty designing. Some 
 engineers who entertain very hazy notions on this 
 subject have not been backward in airing their theories 
 on steam-jacketing in their steam-engine catalogues. 
 While engine-builders display a lack of knowledge on 
 this subject, it is not surprising that steam-users and 
 engine-drivers either hold curious notions or are totally 
 uninformed on the subject. This may be in some 
 measure accounted for by the paucity of the literature 
 devoted to the consideration of steam-jacketing ; and 
 scarcely any reference had been made to the mal- 
 treatment of the steam-jacket previous to the publica- 
 tion of the author's little book on the subject.^ We 
 believe the want of information of a practical type is 
 one of the chief causes of this endless contention 
 respecting the utility of the steam-jacket. There are, 
 however, some indications that more interest is being 
 taken in the practical part of the subject. So we 
 may reasonably hope that, before long, it will receive 
 all the attention from the hands of steam-engine 
 makers which it really deserves. In the meantime, 
 however, the economising influence of the steam-jacket 
 is, in numerous instances, counteracted, if not totally 
 destroyed, arising from : 
 
 1. Faulty designing. 
 
 2. Defective construction. 
 
 3. Inattention on the part of the engine- 
 
 driver. 
 
 The steam-jacket constitutes a very important and 
 valuable detail of the steam-engine : yet, in its design 
 
 * The A buse of the Steam- Jacket Practically Considered, &c. London : 
 E. & F. N. Spon, 125 Strand. 1878. 
 
90 THE ABUSE OF THE STEAM-JACKET 
 
 and construction, it has not received a tithe of the 
 attention that other parts of equal, or less importance, 
 have ; consequently, it is, in far too many instances, 
 little better than a sharn, and serves to exhibit the 
 carelessness or ignorance of the designer. Now, a 
 defect in the design of any other part of an engine 
 would very likely be quickly detected, or it may by 
 its imperfect action cripple the engine ; but a badly 
 designed steam-jacket may work untold mischief 
 undiscovered for years. It may be that the drainage 
 is faulty, and the jacket is acting as a surface con- 
 denser ; thereby aggravating to an alarming extent 
 the very evil it was intended to diminish. When we 
 remember the numerous abortive steam-jackets that 
 have come under our notice during the last few years, 
 we are at no loss to account for the opinions of 
 engineers, respecting the utility of the jacket, being 
 so diametrically opposed. Many of the people who 
 denounce the steam-jacket are those who, being ignorant 
 of its function, are unable to design it properly, and 
 they have evidently tested engines which have had 
 so-called steam-jackets applied, that were in reality 
 water-jackets, acting as small condensers, or otherwise ; 
 and the unsatisfactory results obtained have not, of 
 course, influenced them to alter their creed. 
 
 It is somewhat surprising that there should be any 
 designers left who do not understand the requirements 
 of efficient steam-jacketing. Yet it is not an unusual 
 occurrence to meet with engineers who understand 
 everything connected with the steam-engine except 
 the jacket round the cylinder, and this simple device 
 is to them shrouded in mystery : the moment they 
 attempt to explain its function they become hopelessly 
 entangled. 
 
 The notion these people evidently cherish concern- 
 
MR. STAFFER ON JACKETS 91 
 
 ing the steam-jacket is, that it is simply a ring round 
 or partly round the cylinder into which the steam is 
 conveyed : it being quite immaterial whereabouts in 
 this ring the steam is taken in, or from whence it is 
 drawn. The Editor of Engineering some time ago 
 very wisely remarked : " That to secure the advan- 
 tages of steam-jacketing, it is not sufficient to merely 
 place around the cylinder a casing that may contain 
 steam ; care must be taken that this jacket always 
 does contain steam." 
 
 " Few but those who have actually tried it, fully 
 appreciate how soon a jacket may be rendered ineffec- 
 tive by the accumulation of air or water." 
 
 No one who has given the slightest attention to 
 this subject, can have failed to notice that, notwith- 
 standing the many cylinders which are said to be 
 jacketed, very few are really s^am-jacketed, thoroughly 
 and efficiently. 
 
 Mr. M. D. Stapfer, in a paper on Steam-Jackets, 
 read before the Scientific Industrial Society of Mar- 
 seilles, says : That there are " few engines which 
 have not their jackets partly obstructed." Practical 
 experience confirms the truth of this statement, as will 
 be gathered from the instances of careless jacketing 
 which have come under our notice, now to be recorded. 
 These examples of miserable designing have mostly 
 been discovered in the repairing shop : no more favour- 
 able opportunity can be secured for detecting the weak 
 points in the design and construction of engines than 
 while they are undergoing repairs. 
 
 We will now show, by the aid of illustrations, how 
 the steam-jacket may be rendered of no service through 
 careless designing. 
 
 Our mode of procedure will be to state some of the 
 necessary requirements of efficient steam-jacketing, 
 
92 
 
 THE ABUSE OF THE STEAM-JACKET 
 
 and test our cylinder sections by these principles, so as 
 to ascertain whether the steam-jackets are properly 
 designed or not. 
 
 1. The steam-jacket should completely encircle the 
 cylinder from end to end. We have several cylinders 
 
 Fig. 25. Faulty design. 
 
 Fig. 26. Faulty design. 
 
 Fig. 27. Faulty design. 
 
 illustrated, in which the steam-jacket is only taken 
 partly round the cylinder: in some cases only two- 
 thirds round it. Figs. 25, 26, 27 and 47 show 
 examples of this fault, which generally occur in those 
 instances where the cylinder and the jackets are com- 
 bined in one casting. In cylinders that have the liners 
 
EXHA UST-PASSA GES 
 
 93 
 
 cast separately and afterwards inserted into the casing 
 or jacket, this point is fully and invariably carried out, 
 as will readily be understood by referring to figs. 30, 
 31, and 36. 
 
 2. The exhaust-chamber should present as small an 
 area of surface to jacket steam as possible, and in no case 
 should the exhaust steam be made to travel partly round 
 the cylinder, either in contact with the steam in the jacket, 
 
 Fig. 28. 
 
 or the working body of the cylinder. More steam is 
 dissipated by large exhaust-passages than some would 
 suppose : the steam in the cylinder or in the jacket is 
 cooled at every stroke of the engine, and thus counter- 
 acts to a great extent the good effects of the jackets. 
 At one time it was a very usual thing to jacket 
 cylinders with exhaust steam. Some eminent engineers 
 have carried this fallacious idea into practice. Surely 
 these persons have not imagined that the damp and 
 
94 THE ABUSE OF THE STEAM-JACKET 
 
 cool exhaust steam (which possesses a notorious pro- 
 pensity for absorbing heat) would impart warmth 
 through the cylinder sides to steam of a much higher 
 temperature within the cylinder. In order to show 
 the hazy notions entertained about steam-jacketing, 
 we are tempted to refer to a little episode which 
 happened a few years ago between two rival steam- 
 engine makers. One firm was in possession of a patent 
 for a steam-jacketed cylinder for traction engines, in 
 which the steam in its passage to the working cylinder 
 was made to traverse round the jacket-casing (by the 
 way, however, not a desirable plan, in spite of its being 
 a patent). Six years afterwards, another firm made a 
 
 steam-jacketed cylin- 
 der, but, instead of the 
 steam from the boiler 
 being carried round 
 the working barrel, 
 the exhaust steam was 
 led into the jacket- 
 , casing previous to its 
 
 Fig. 29. Steam-jacket badly drained. 3 r 
 
 exit into the chimney. 
 
 At first sight the sectional drawings of the two cylin- 
 ders appear to be alike, but they are totally opposite 
 in reality. The curious part is, however, that the last- 
 named exhaust-jacketed cylinder was considered by 
 the former firm to be an infringement of their patent, 
 showing that the persons who possessed the steam- 
 jacket had little knowledge of the subject, or they 
 would have repudiated the notion of considering such 
 an abortion as an exhaust-jacket to be an infringe- 
 ment of their rights. 
 
 Headley's celebrated Puffing Billy of 1813, had its 
 cylinders provided with sham jackets ; but it appears 
 somewhat curious that the next case, and the only case 
 
EXHA UST-JA CKETS 
 
 95 
 
 of jacketed cylinders for locomotives (save in the com- 
 pounded ones of recent date), should also turn out to 
 be a similar counterfeit. We now refer to Beattie's 
 patent improvements in locomotive cylinders, introduced 
 in 1858, which were nothing more than exhaust- jackets. 
 Cylinders intentionally provided with a jacket to be 
 supplied with steam from the exhaust may, now-a-days, 
 be rare ; still, there are many cylinders, if not inten- 
 
 m 
 
 
 *%ffl%ffi 
 
 
 /f 
 
 exnavsc 
 
 I 
 
 W 
 
 V 
 
 V/777, 
 
 
 
 
 1 
 
 T 8 
 
 Fig. 30. American portable engine cylinder. 
 
 tionally exhaust-jacketed, yet a large proportion of 
 their surface is accidentally exposed to the action of 
 the exhaust steam. 
 
 Non-jacketed cylinders have generally a large portion 
 of their outside surface exposed to the exhaust steam. 
 The metal of the cylinder being a good conductor, much 
 of the working steam inside is robbed of its heat and 
 wasted in continually warming up this metal, to be 
 constantly cooled on the outside by the action of the 
 
96 
 
 THE ABUSE OF THE STEAM-JACKET 
 
 damp spent steam and the atmosphere. Much heat is 
 dissipated in this process, and more or less condensa- 
 tion within the cylinder is the result. 
 
 When cylinders are steam-jacketed, this surface in 
 contact with the exhaust draws a large amount of 
 heat from the steam in the jacket. To prevent this 
 waste the exhaust should be made to pass quickly 
 away from the cylinder by as direct and short a course 
 
 Fig. 31. Traction engine cylinder. 
 
 as practicable, allowing the smallest possible surface of 
 the cylinder to be touched by it in its passage to the 
 atmosphere. Figs. 25, 26, 29 and 30 show a large 
 portion of the working barrel exposed to the exhaust 
 steam. 
 
 Fig. 28 shows an American locomotive cylinder, the 
 working steam in which is uselessly spending heat in 
 drying the exhaust: this is a serious drawback in 
 many of the outside cylinders as arranged on foreign 
 
FA ULTY EXHA UST PASSAGES 
 
 97 
 
 railways. In experiments, such cylinders reveal an 
 enormous amount of condensation. In some English 
 outside cylinder locomotives the exhaust is in contact 
 with no less than 292 square inches of the exterior of 
 the barrel. The exhaust in other engines does not 
 touch the exterior of the barrel : they have been 
 specially designed to avoid loss of heat. Fig. 35 shows 
 an otherwise neatly-designed Corliss engine-cylinder 
 with a grave defect ; the whole of the bottom part of 
 the steam-jacket is in contact with an enormous exhaust 
 
 Fig. 32. Faulty design. 
 
 chamber. To a certain extent fig. 33 is defective in 
 this respect. How much better it would have been if 
 the exhaust steam had been taken away through the 
 cylinder foot at each end, and thus have saved con- 
 siderable steam. Fig. 36 shows the exhaust passing 
 down the foot of a cylinder of an excellent type. Fig. 
 32 represents a sectional end elevation of a horizontal 
 engine cylinder, in which the exhaust steam is made 
 to traverse nearly half-way round the outside of the 
 jacket ; a common and pernicious practice with some 
 
 G 
 
98 
 
 THE ABUSE OF THE STEAM-JACKET 
 
 continental engineers. Fig. 30 illustrates a sectional 
 plan of an American portable engine cylinder wherein 
 a large proportion of the jacket surface is exposed to 
 the exhaust steam. Fig. 37 shows the commonest 
 form of exhaust chamber with the same fault. 
 
 Fig. 38 gives a better method of conducting the waste 
 steam away, so that the exhaust chamber scarcely 
 touches the space occupied by the jacket steam. 
 
 These exhaust passages may appear in themselves 
 to be trifling matters to write about, but economy is 
 
 Fig. 33. 
 
 brought about by our attention to a number of small 
 details, each of which in itself seems insignificant. 
 
 3. The jacket must l)c supplied with steam of the full 
 boiler pressure. The supply pipe must l)e of ample area 
 in order to secure these results. In days gone by these 
 essential requirements must have been understood, for 
 it has not been unusual to insert the cylinder inside 
 the steam-space of the boiler. 
 
 Murdock's little locomotive of 1784 was thus 
 jacketed ; so were Trevithick and Vivian's high-pressure 
 engines (figs. 3 and 4). Cambridge's portable engines 
 of 1843 had their cylinders inserted vertically in the 
 
MR. PORTER'S CYLINDER 
 
 99 
 
 steam-space of the boiler (fig. 5). Hornsby's portable 
 engines of 1850 had, and some that are made in our 
 times, have the steam cylinders placed horizontally 
 
 s 
 
 within an elevated steam chamber at the fire-box end 
 of the engine (see fig. 6). Clayton and Shut tie worth 
 had the steam-jacketed cylinders inserted in the top 
 of the smoke-box, the steam in the jacket preventing 
 
100 
 
 THE ABUSE OF THE STEAM-JACKET 
 
 any over-dryness in the working cylinder, and the heat 
 of the escaping gases in the smoke-box keeping up 
 the heat of the jacket steam. Having named the 
 requirements necessary for securing the jacket's steam- 
 supply being properly attended to, let us see how 
 these essential conditions to effective steam-jacketing 
 are complied with by the engine-makers of the present 
 generation. The steam-supply pipes for the jackets 
 
 Fig. 35. Faulty exhaust outlet. 
 
 of marine engines, instead of always being open to the 
 boiler, are generally provided with cocks, and the 
 engineer can have steam in the jackets or not as he 
 pleases. 
 
 A large number of horizontal fixed-engines have 
 their jackets supplied with steam from the slide-valve 
 chest. These examples have not steam of the full 
 boiler pressure in their jackets, and the supply being 
 
CRACKED CYLINDER* 
 
 101 
 
 affected by the stop-valve, the cylinders are not heated 
 gradually, and hot ready for work. Therefore the 
 engine has to be started very slowly and run with the 
 stop-valve partly open for several minutes in order to 
 warm up the cylinder -and to give the condensed steam 
 from the cold cylinder time to run away. In not a few- 
 
 Fig. 36. Approved desigi 
 
 cases cylinders of this type have been cracked by 
 having the steam turned on suddenly. Figs. 39 and 
 40 show sectional views of a horizontal stationary 
 engine cylinder, with the steam-jacket supply taken 
 from the valve-chest, with all its attendant faults ; 
 but the makers of this cylinder, being anxious to 
 display some originality of a questionable type, have 
 
102 
 
 THE ABUSE OF THE STEAM-JACKET 
 
 carefully carried the steam-supply through the exhaust 
 chamber also, in order to further reduce the tempera- 
 ture of the jacket steam, which is already much lower 
 than the steam in the boiler. 
 
 When engines have their jackets filled with steam 
 from the supply pipe above the stop-valve, these 
 
 Fig. 37. Large exhaust port. 
 
 Fig. 38. Approved exhaust outlet. 
 
 supply pipes are in many cases much too small to 
 efficiently feed a large steam-jacket ; and these pipes 
 are generally exposed instead of being neatly clothed 
 or arranged beneath the lagging. We recently saw a 
 J-inch copper pipe fitted to a 16-inch cylinder: such a 
 means of jacketing could not be of much service. 
 
SMALL PIPES 
 
 103 
 
 The following remarks respecting small steam-supply 
 pipes to jackets occur in the second report of the 
 Research Committee on " The Value of the Steam - 
 Jacket." Experiments were made at Messrs. J. & P. 
 
 Fig. 39. Faulty steam-jacket supply. 
 
 Coats' Thread Works, Paisley, in 1889 by Mr. Michael 
 Longdridge, on a pair of single-cylinder condensing 
 horizontal Corliss engines. Cylinders 25*06 inches 
 diameter ; 48 inches 
 stroke : the body and 
 both ends of each cylin- 
 der were jacketed. Steam 
 was supplied to the 
 jackets from the main 
 steam-pipe through f -inch 
 pipes. The economy re- 
 suiting from steam in the Fig ' 40 ' - 
 ends or cylinder-lids was 
 
 only 1*3 per cent. ; and the gain resulting from steam 
 in all the jackets was very low, viz., 2*5 per cent. 
 " For the size stated of the engine, such small pipes 
 were, of course, inadequate to supply sufficient steam 
 to jackets. It would be interesting to know whether 
 
104 
 
 THE ABUSE OF THE STEAM-JACKET 
 
 the poor economy obtained in that instance by the 
 use of jackets was due to the want of sufficient pres- 
 sure of steam in the jackets, and therefore to the low 
 temperature in the jackets."^ 
 
 The worst and most common examples of inefficient 
 steam-jacketing are those wherein the working steam 
 is made to traverse round the jacket previous to 
 entering the cylinder ; a practice which in the Cornish 
 engine has been abandoned, t and should be rejected 
 
 Fig. 41. Faulty design. 
 
 in all engines, seeing that the stearn is robbed of its 
 heat and condensed before it reaches the cylinder; 
 the "water resulting from this refrigeration being 
 carried with the steam into the cylinder. 
 
 Figs. 27, 32, and 41 are illustrations of this class : 
 the jacket may be said " to drain itself through 
 
 * Mr. W. Schonheyder, p. 497 of Inst. of Mechanical Engineers. 
 Second Report on (< The Value of the Steam- Jacket." 
 
 f In the earlier Cornish jacketed engines the steam for the engine 
 was taken from the steam-jacket, but this plan has subsequently been 
 discontinued, and the steam-pipe is now always made to lead direct from 
 the boilers to the top nozzle. Fig. 42 shows this clearly. 
 
CORNISH ENGINE CYLINDER 
 
 105 
 
 Fig. 42. 
 
106 THE ABUSE OF THE STEAM-JACKET 
 
 the cylinder." '^ In many compound engines of 
 large sizes the steam on its way to the high-pressure 
 cylinder passes round the jacket of the small cylinder, 
 does work in that cylinder, and then makes its escape 
 to reach the low-pressure cylinder by the same cir- 
 cuitous route. Jacketing the high and low-pressure 
 cylinders with such steam must cause an immense 
 loss ; and, strange to say, there are hundreds of 
 cylinders on all classes of engines in which this 
 species of jacketing obtains. 
 
 We noticed in one of the engineering journals a 
 compound side-by-side horizontal engine, in which 
 the steam 011 its way to the high-pressure cylinder 
 traversed the outside of an interheater, then round 
 the outside of the high and low-pressure cylinders in 
 the manner indicated above. The editor of the 
 journal says : " We must say that we think this 
 plan of transmitting heat to the working steam at the 
 expense of steam just about to do work is not at all 
 an advisable one. The almost inevitable result is to 
 make the steam so wet that the benefits gained by 
 jacketing and re-heating are more than counter- 
 balanced." 
 
 We are of opinion that, with such a plan of 
 steam-jacketing, and one which is sadly too common, 
 no advantage, but positive loss, results, so we need 
 not be astonished to hear doubts raised occasionally 
 respecting the jacket's utility ; thus demonstrating 
 the truth of our previous remarks regarding the 
 
 * It will be seen, however, that this arrangement promotes the 
 circulation of the steam in the jacket. The cylinders of traction 
 engines are generally arranged in this manner ; the jacket space is made 
 unusually large so as to act as a steam dome, as per fig. 31 : the 
 drainage is also well carried out as shown by fig. 55. But, where the 
 jacket space round the cylinder is contracted as in the figures referred 
 to, the plan must possess the faults we have named. 
 
DRY STEAM 107 
 
 ignorance displayed by engine- makers relative to 
 this subject. 
 
 Mr. Northcott in The Theory and Action of the 
 Steam- Engine, says : " In all cases the jacket should 
 be distinct from the cylinder, as when the steam is 
 passed through a jacket on its way to the cylinder, 
 the water condensed in the jacket is carried with the 
 steam into the cylinder, and the result is much the 
 same as would be produced without the jacket." 
 
 In order to obtain the very best results, not only 
 has it been the rule to obtain steam of the same 
 temperature in the jacket as the initial steam in the 
 cylinder, but recently cases have occurred wherein 
 the jackets have been supplied with steam of a higher 
 .pressure than the working steam in the cylinder. 
 There is no reason in many places why such a system 
 of jacketing should not be carried into effect. In 
 another part of the work we give some particulars 
 which show the advantages of jacketing with high- 
 pressure steam. In Hopkinson's Engineers Guide, the 
 following sentence occurs : " It is clear then, that to 
 secure the greatest attainable economy by steam- 
 jacketing, they must be supplied with steam of a much 
 higher temperature, and higher in proportion as the 
 metal is thicker through which the heat must be 
 transmitted." 
 
 4. Not only should high-pressure steam be used in 
 the jacket, but, if we are to realise the best results, we 
 must have the working steam as dry as possible, because 
 all wet steam admitted into the cylinder is evaporated 
 during the stroke by heat abstracted from the jacket 
 The steam-pipes from the boiler should have provisions 
 for draining, so as to prevent the condensed steam 
 from being carried into the cylinder. We believe 
 that priming boilers are more numerous than some 
 
108 
 
 THE ABUSE OF THE ^TEAM-JACKET 
 
 people imagine, and much of the water we are some- 
 times troubled with probably comes from this source, 
 causing an enormous loss of power. A good water- 
 
 collector should be provided on all steam pipes : the 
 pipes should be carefully clothed. In fig. 28 the 
 steam-pipe of this locomotive cylinder is not only ex- 
 
IVET STEAM 
 
 109 
 
 posed to the cold air, but it is also partly in contact 
 with the exhaust pipe, and the working steam is 
 uselessly spending its heat in drying the exhaust 
 
 Fig. 44. Mr. Bollinckx's Cylinder. 
 
 steam. Kespecting this wet steam supply, Mr. North- 
 cott says : Owing to this cause " it is not unusual 
 to see engine diagrams in which the expansion curve 
 
110 THE ABUSE OF THE STEAM-JACKET 
 
 rises considerably above even the hyperbolic curve." 
 In all such cases the loss must be very considerable. 
 
 In Mr. Bollinckx's cylinder, shown by figs. 43 and 
 44, " to prevent water being taken into the cylinder 
 with steam, the well-known system of ' knocking the 
 water out of it ' is used. The steam before entering 
 the cylinder passes into the jacket it enters at the 
 top, and, striking the metal of the liner, it has the 
 
 Fig. 45. Draining pipe from jacket. 
 
 water knocked out of it dry steam passing right and 
 left to the admission valves. The water falls to the 
 bottom of the jacket, and the result is such that drain- 
 cocks are not needed."^ 
 
 5. The jacket should be open to the boiler at ^all 
 
 times, and not affected by the stop-valve ; it will thus be 
 
 heated gradually as the steam is raised, and always hot 
 
 ready for work ; therefore, no steam will be required 
 
 * The Engineer, 18th December 1885. 
 
STEAM PIPE* 
 
 111 
 
 for blowing through the cylinder for warming it. 
 When the jacket steam is taken from the steam 
 chest, as referred to previously, this fault obtains. In 
 small engines it is not necessary to provide any means 
 for shutting off the steam from the jacket, but large 
 engines are generally fitted, so that the steam may be 
 turned off; care, however, should be taken to arrange 
 these cocks or appliances so that they may not be 
 tampered with by being turned off or on, to suit the 
 fancy of a meddlesome engine-driver. Fig. 62 shows 
 
 Fig. 46. Portable engine cylinder. 
 
 the steam supply for the jacket independent of the stop- 
 valve. Any water collecting in the steam pipe should 
 pass into the jacket rather than into the cylinder. 
 
 6. The steam-supply pipe should enter the jacket at 
 sucli a point that a thorough circulation of the steam 
 within may be secured and maintained, and the accumu- 
 lation of air at any part made impossible. 
 
 Figs. 25 and 47 show sections of cylinders, the 
 jacket of which is only taken partly round the cylinder ; 
 no circulation of the steam takes place in the jacket, 
 
112 
 
 THE ABUSE OF THE STEAM-JACKET 
 
 and air collects at the top. The following incident 
 occurred at a trial of portable engines, which appears 
 to prove that air does sometimes accumulate at the 
 highest point of the jacket, and prevent the jacket 
 becoming heated by the steam, notwithstanding that 
 some tell us that such cannot be the case. 
 
 A correspondent in Engineering says : " The 
 cylinder of one engine was steam-jacketed : being on 
 the top of the boiler, the. admission of the steam was 
 direct to the jacket : it might be supposed that the 
 
 Fig. 47. Traction engine cylinder deficient circulation. 
 
 jacket would be heated as the steam rose ; the jacket 
 felt quite cold with sixty pounds pressure of steam in 
 the boiler, until the safety-valve (which was on the 
 top of the cylinder, in communication with the jacket) 
 being eased a little, a current was formed in the steam, 
 showing clearly that the air must be expelled before 
 they can be heated properly." 
 
 At the present time, there are hundreds of portable 
 engines being sent out by celebrated makers, having 
 the most worthless so-called steam-jackets, but, in 
 
AIR-JACKETS 113 
 
 reality, they are air-jackets, because no trouble has 
 been taken to cause any circulation of the jacket 
 steam. 
 
 The cylinders are bushed in the usual manner: a 
 small hole is drilled into a pocket at one end of the 
 cylinder at the lowest part of the annular space. 
 Through this hole the steam supply to the jackets 
 is taken, but, as there is no other opening into the 
 jacket, it is impossible for it to be of any service, 
 because the greater part of the space will be filled 
 with air. Such jackets must be an immense source 
 of loss ; the steam in the working cylinder not only 
 derives no benefit, but positively has to warm up the 
 stagnant air in the jacket. *We cannot denounce 
 such counterfeits too strongly ; it would be far better 
 for some makers not to attempt to steam-jacket their 
 cylinders at all, unless the jacketing can be properly 
 designed so as to be an advantageous agent for econo- 
 mising fuel. 
 
 Another portable engine-maker supplies steam to 
 the jackets of their compound cylinders in a similar 
 manner to the above, but the jackets are in com- 
 munication with tubular stays, connecting the cylinder 
 and crank-shaft brackets together, and some circulation 
 of the steam is set up in the jackets by means of a 
 circulating pipe from the stay to the boiler; in other 
 words, steam passes through the stay from the jacket 
 to the boiler. Another plan is to place the safety- 
 valves on the top of the cylinder in communication 
 with the jacket steam, and also open to the boiler, as 
 is done on most road locomotive cylinders, (figs. 31, 46, 
 and 58). 
 
 Mr. Mair, a great authority on steam-engine testing, 
 recently said respecting faulty steam-jackets : " In 
 some cases the jackets are only air-traps. The steam 
 
 H 
 
114 THE ABUSE OF THE STEAM-JACKET 
 
 should enter the jacket in such a position so as to pre- 
 vent this accumulation of air." We illustrate at fig. 
 43 a section of a cylinder made by Mr Bollinckx 
 of Brussels, to which reference has previously been 
 made. Mr. Bollinckx, " it is worth notice, attaches 
 the greatest importance to taking steam in at the top 
 of the jacket. It is to the neglect of this precaution, 
 he holds, that the unsatisfactory results now and then 
 obtained with jackets is due." * 
 
 If the jacket steam cannot be taken in at the top 
 and drained from the bottom, an air-valve will answer 
 the purpose, placed on the highest part of the jacket ; 
 but we strongly recommend the safety-valves being 
 placed on the top as just named. 
 
 In a description of a triple-expansion condensing 
 engine by Mr. F. Schichau of Ebling, Prussia, in 
 Gassier 's Magazine for May 1893, the following re- 
 marks occur : 
 
 " The first two cylinders have steam-jackets supplied 
 with steam at boiler-pressure, and the jackets have 
 small air-valves to prevent air binding, and traps for 
 draining off the water of condensation." 
 
 Figs. 58 and 59 show sections of a compound 
 traction-engine cylinder. The steam for the jacket is 
 taken to the top from which the stop-valve draws its 
 supply ; the drain is at the lowest point. Two safety- 
 valves are also placed on the top of the jacket. It is 
 impossible for air to be trapped in such a steam- 
 jacket, t 
 
 Messrs. M'Intoch, Seymour & Co., of Auburn, New 
 York, exhibited a 1200 horse-power double tandem 
 compound engine at the World's Fair. The following 
 account of the methods adopted for securing good 
 
 * The Engineer, 18th December 1885. 
 
 t "We are indebted to Engineering for figs. 58 and 59. 
 
NIVERSITY 
 
 MR. HALPIN'S 
 
 circulation in the jackets may be of interest. " The 
 high-pressure cylinders are provided with steam- 
 jackets, and the receivers between the cylinders are 
 filled with copper-heating coils, presenting a large 
 amount of heating surface, and tending to give per- 
 fectly dry steam at the entrance to the low-pressure 
 cylinders. 
 
 " The builders argue that the cause of inefficiency 
 of steam-jackets on high-pressure cylinders, as 
 ordinarily made, is lack of proper circulation through 
 
 Fig. 48. Mr. Halpin's Cylinder. 
 
 the jackets, and that a very rapid circulation is 
 necessary to render them of service. By the present 
 arrangement, the temperature of the steam in the re- 
 ceiver being much lower than that in the coil, a very 
 considerable amount of condensation takes place in 
 the receiver coil, and as this is fed from the high- 
 pressure cylinder jacket only, a brisk circulation is 
 insured in the latter. The pipes from the high- 
 pressure cylinders to the receivers are also fitted with 
 
116 THE ABUSE OF THE STEAM-JACKET 
 
 steam separators to catch any water which may be 
 carried along by the passing steam." * 
 
 We are pleased to find that our foremost engineers 
 are beginning to recognise the importance of obtaining 
 a thorough circulation of the steam within the jacket. 
 In order to obtain this result, Mr. Chas. T. Porter of 
 Montclare, U.S.A., has recently, among other patents 
 connected with the steam-engine, shown a method of 
 distributing the jacket steam by means of a perforated 
 pipe (see fig. 34). Mr. Porter says : " To insure that 
 the current shall move through every part of each 
 jacket without permitting air to accumulate anywhere, 
 the steam is introduced through a perforated pipe ex- 
 tending the whole length of the jacket on the upper 
 side, and taken 'away at several points equally distri- 
 buted at the bottom." t 
 
 7. It is essential that the provisions made for the 
 drainage of the jacket should ~bc most efficient and com- 
 plete. To fully answer their end, they should be so 
 planned that they continually operate, irrespective of 
 any control from the attendant ; indeed, it should be 
 impossible for his negligence or interference to hinder 
 or impair their action. This neglected drainage is 
 the most prevalent, and, by far, the most serious evil 
 which the steam-jacket has to contend with. It is an 
 abuse which is perhaps working greater mischief than 
 all other detrimental causes combined. 
 
 By the defective arrangements, and, in some cases, 
 the total omission of any provisions made for the 
 drainage of the jacket, an otherwise well-designed 
 steam-jacket can be transformed from an economising 
 agent to the veriest sham, acting as a surface- 
 condenser instead of a heat-preserver, and thereby 
 
 * Gassier 's Magazine, July 1893. 
 t Iron Age, 3rd May 1894. 
 
JACKET DRAINAGE 
 
 117 
 
 aggravating to an alarming extent the very evil it was 
 intended to dimmish. In spite of our engineering 
 boasts, we may with advantage take notice of the 
 methods pursued by our forefathers in this respect. 
 Let us take the case of the steam-jacketed Cornish 
 engine of a hundred years ago, for an instance of care- 
 ful jacketing. 
 
 The jacket was supplied with steam by means of a 
 sufficiently large pipe, connecting the highest part of 
 the boiler with the highest part of the jacket space, 
 
 Fig. 49. An efficient steam -jacketed cylinder. 
 
 and the drain-pipe at the bottom of the jacket led the 
 condensed steam into the water-space of the boiler. 
 The boilers were placed on a lower level than the 
 engines, so that the drainage was effected by gravita- 
 tion: the drain-pipe was of ample size and was always 
 open to the boiler below the water-line. Where such 
 a method of drainage cannot be carried out in such 
 like engines, an efficient steam-trap should always be 
 connected to the lowest part of the steam-jacket. We 
 have some steam-traps that will deliver the drainage 
 direct to the boiler, described later on. 
 
118 THE ABUSE OF THE STEAM-JACKET 
 
 Many years ago Mr. Maw suggested the use of a 
 small pump for constantly drawing the water of con- 
 densation from the jackets and forcing it into the 
 boiler. " We think this mode of draining the jackets 
 would be preferable to any arrangement dependent 
 upon the attention of the driver, while it has the 
 advantage of returning the water to the boiler at 
 practically the temperature of the steam. 
 
 " The utilisation of the water of condensation as hot- 
 feed would be quite an appreciable economy." * 
 
 While on the subject of the proper drainage of 
 jackets, we quote the following respecting some first- 
 class compound marine engines : " The steam for the 
 jackets is taken direct from the boilers, and the drain- 
 pipes are carried below the water-level of the boilers, 
 so that the steam-jackets of the cylinders form a part 
 of the boilers while they are in use."t 
 
 Very little difficulty should be experienced in 
 properly draining the steam-jackets of agricultural 
 engine cylinders where these are placed upon the top 
 of the locomotive type of boilers. But here is an 
 instance of carelessness in this simple matter of the 
 drainage. 
 
 A few years ago, some repairs were being done to 
 a ten horse-power expansive portable engine, made by 
 a celebrated firm. 
 
 The cylinder and covers were jacketed, the lids 
 being supplied with steam from the circumferential 
 jacket by means of three or four holes drilled through 
 the end of the cylinder; and, opposite these, similar 
 holes were provided in the covers. After removing 
 these lids we found all the holes in each one filled 
 we may say plugged with red lead one inch thick, 
 
 1, 29th April 1881. 
 t The Engineer. 
 
DEFICIENT DRAINAGE 
 
 119 
 
 for evidently every time the cover-joints had been 
 made, a fresh layer was added in each hole, to account 
 for the thickness of lead named. After clearing out 
 the holes, which was no easy matter, as the lead 
 was rammed in very tightly, we saw that the 
 jackets of the covers were full of water, and, judging 
 from appearances, they had been in this state for 
 years ; it is almost needless to remark that this is a 
 very poor plan for supplying jacketed covers with 
 
 Fig. 50. An efficient steam-jacket. 
 
 steam. But this is not all, for, when the holes were 
 being cleared out in the ends of the cylinder, it was 
 discovered that the circumferential jacket also was 
 half full of water. The drainage of this steam-jacket 
 had been entirely overlooked by the designer, for 
 it was impossible to prevent the accumulation of 
 water in it without altering the arrangement con- 
 siderably. Fig. 54 shows a method of drainage 
 adopted on a portable engine by means of holes 
 drilled up the holding-down bolts, which cannot be 
 
120 THE ABUSE OF THE STEAM-JACKET 
 
 recommended. Fig. 55 shows a good drainage arrange- 
 ment independent of the steam-supply, an improvement 
 on fig. 46. 
 
 But we have known many instances wherein the 
 bottom part of the jacket has been drained, but, owing 
 to defects in the design, water has found some shelf 
 or pocket where it may lodge in the higher part of 
 the jacket space. Figs. 25, 26 and 27 are examples 
 of this species of defective drainage. 
 
 In figs. 26 and 27, for instance, the steam is made 
 to pass round the cylinder body over water to reach 
 the steam-chest ; this water, lying in contact with 
 the cylinder wall, tends to waste the heat of the 
 working steam, and causes other evils on the top of 
 the jacket, while a large area of the side of the cylin- 
 der body is in contact with the cooling influences of 
 the exhaust steam. 
 
 But fig. 27 represents a worse case still, for, not 
 only is the working steam made to traverse round the 
 cylinder, but it must, before it reaches the stop-valve, 
 either pass through a body of water, or carry some of 
 it with it into the cylinder. Fig. 29 represents an 
 example, wherein the bottom of the jacket will always 
 contain some water > because the jacket drain-cock is in 
 a line with the cylinder drip-cocks, several inches 
 above the bottom of the jacket, the levers of the three 
 cocks being coupled together ; not only so, but the 
 fact of the drain-cock being connected to the drip- 
 cocks, shows that the condensed steam will never be 
 blown out except when the cylinder-cocks are opened : 
 and the attendant may only do this two or three times 
 a day, which is not nearly often enough, as the water 
 within the jacket should be got rid of as quickly as it 
 is formed. The injurious effects occasioned by such 
 an improper arrangement will be apparent to all ; for 
 
COMPOUND ENGINE CYLINDER 
 
 121 
 
122 THE ABUSE OF THE STEAM-JACKET 
 
 it is more than probable that the jacket will often be 
 full of water. 
 
 In designing all classes of cylinders, care should be 
 taken to avoid all shelves or pockets, either at the top 
 or bottom of the steam-jacket, where water may find 
 a lodging place. Several engineers entertain an 
 erroneous impression respecting the drainage of steam- 
 jackets ; they fancy that, if the drain-pipes are occasion- 
 
 Fig. 52, 
 
 ally opened, that will be sufficient. It must be dis- 
 tinctly understood that no occasional blowing out will 
 do ; the condensation of the jacket steam is continuous, 
 hence the water resulting from this incessant cause 
 should be removed as quickly as it is formed. 
 
 Fig. 45 shows a good plan adopted by another firm 
 for draining the steam-jackets of their compound 
 portable engines. Two pieces of steam-pipe are cast 
 
THIN LINERS 123 
 
 into the lower part of the jacket passing through the 
 foot of the cylinder, opening up a communication be- 
 tween the lowest part of the jacket and the boiler. 
 Let us hope, however, that these pipes are provided 
 for the drainage only, and not for the supply of the 
 jacket ; for, if so, the remarks made on previous pages 
 apply to this cylinder also. 
 
 In figs. 53 * and 63, the high and low-pressure 
 cylinders and the intermediate receiver are immersed 
 in steam of the full boiler pressure : the drainage is 
 well carried out. Fig. 63 has two drainage pipes at 
 the lowest part of the cylinder foot, not shown in the 
 drawing. The safety-valves are placed on the top. 
 We have previously referred to Mr. Porter's efficient 
 steam-jacket. It will be seen from fig. 34 that the 
 condensed steam is drained from the jacket round the 
 cylinder and the spaces in the cylinder heads by means 
 of four separate exit pipes, so as to insure perfect 
 circulation and drainage. 
 
 8. The ivorking barrel of the cylinder should be made 
 as thin as possible, and of the best conductor of heat. 
 "The thickness of the metal of the cylinder, that is, 
 between the steam in the jacket and the internal 
 surface of the cylinder, is of very great importance, 
 because the transmission of heat, both in time and 
 quantity, is inversely as the distance passed through, 
 and, therefore, the shorter such distance, the more 
 efficacious will be the steam in the jackets."! 
 
 It is a well-known fact that many makers of port- 
 able engines cast the walls and partitions of their 
 cylinders of such a thickness as to seriously interfere 
 with the transfer of the heat from the jacket to the 
 
 * "We are indebted to Messrs. Crosby Lockwood for permission to use 
 this block, 
 t Hopkinson's Engineer's Guide. 
 
124 THE ABUSE OF THE STEAM-JACKET 
 
CONSTRUCTION OF CYLINDERS 125 
 
 cylinder ; these thick walls are introduced to lessen 
 the risk from defective castings in the foundry, for 
 the steam-jacket and cylinder when made in one, is 
 a somewhat complicated and troublesome casting to 
 make. Herein consists one of the most valuable advan- 
 tages of casting the cylinder and bush separately ; the 
 bush may be made as thin as possible, and as hard as 
 practicable, reducing the wear to a minimum, so that re- 
 peated re-boring will not be necessary, and, perhaps, under 
 some conditions, re-boring may not be required at all. 
 We may remark in passing, that the bush system 
 of steam-jacketing is now generally adopted for all 
 classes of engines. It possesses the following advan- 
 tages over the old system of casting the steam-jacketed 
 cylinder in one piece : 
 
 (1) Eeduced cost for moulding. 
 
 (2) Minimum risk from defective castings, as all 
 the walls or partitions can be examined and tested 
 before the liner is inserted. 
 
 (3) The liner can be cast in very hard metal and the 
 shell in softer metal. The liner may also be made of any 
 other material than cast-iron, such as steel, hard- 
 brass, phosphor-bronze, &c. The liner may be made as 
 thin as practicable and of equal thickness throughout. 
 
 (4) One pattern of cylinder casing may be used 
 for several sizes of engines, the liners being made to 
 suit the different pistons. 
 
 Figs. 30, 31, 36, and 46 show the liner system of 
 cylinder construction clearly. 
 
 The Editor of The Engineer some time ago suggested 
 the use of hard brass or gun-metal liners for high- 
 pressure cylinders. " Properly made, the material is 
 much harder than cast-iron, and will take a beautiful 
 surface ; while this material, being an excellent con- 
 ductor of heat, would comply with one of the funda- 
 
12(5 THE ABUSE OF THE STEAM-JACKET 
 
 mental conditions of eminent success in using the 
 jacket." Phosphor-bronze is now largely used for all 
 manner of purposes : it would not only be in keeping 
 with the spirit of the times to propose this material 
 to be used for cylinder liners, but it has, likewise, 
 several favourable properties to recommend it, the 
 chief being its conductivity, which is more than three 
 times greater than cast-iron. Fig. 43 shows an 
 excellent method of construction. 
 
 Steel liners for steam-jacketed cylinders were first 
 used on portable engines by Mr. Barrett of Beading. 
 They are now used in America for Corliss engines of 
 large dimensions. 
 
 It is only recently that they have been applied to 
 marine engines : the credit of their introduction is due 
 to Mr. Allen of Sunderland, who read a paper on this 
 subject before the Institution of Engineers and Ship- 
 builders of Scotland, containing an interesting account 
 of their successful application to several high-pressure 
 cylinders. We believe that steel liners are not adopted 
 in the merchant marine engines of the present day, 
 because of their extra first cost. 
 
 Messrs. Sir Joseph Whitworth & Company have, 
 during the last twenty years, supplied some hundreds 
 of their fluid-pressed steel liners to the war-ships of 
 various governments. They are prepared to' make^ 
 these liners from one-quarter of an inch in thickness 
 up to any diameter. 
 
 Previous to the introduction of steel liners in the 
 Admiralty service, fractured cylinders were of frequent 
 occurrence, in fact, cracked cylinders were the rule 
 rather than the exception ; and when the liners did 
 not crack, they scored, but, since steel has been used, 
 few have failed, and not one of Messrs. Whitworth's 
 liners have cracked. 
 
MR. HALPIN'S CYLINDERS 127 
 
 It has been the custom for some time past, with 
 several firms, to make their cast-iron liners as thin as 
 practicable, and as hard as possible. In order to give 
 the necessary strength to the liners, there were added 
 a series of ribs placed longitudinally an4 transversely 
 at suitable distances apart on the outside of the liner. 
 We have a liner shown in fig. 50, transversely ribbed 
 for a totally different purpose, as we shall explain. 
 The outer casing of the cylinder is cast in one with 
 the steam-chest, which completely encloses the cylinder 
 liner as clearly shown. When steam is admitted to 
 the outer casing it supplies the valve-box, the circum- 
 ferential jacket, and the cylinder-covers, which are all 
 in communication with each other. The flange of the 
 engine frame answers for the front cylinder-cover, to 
 which the liner and the outer casing are separately 
 bolted. There are two back covers, one, A, for the 
 liner, and a second one, B, for the casing, the space 
 between the two being open to the jacket steam. 
 The outside of the liner is provided with a number 
 of ribs, which completely encircle its circumference, 
 except on the part taken up by the ports and the 
 valve-face : these ribs are applied for the purpose of 
 absorbing the heat from the jacket steam and trans- 
 mitting it to the interior, to keep up the heat of the 
 working steam. The inside cover, A, is similarly 
 ribbed on both sides, the piston being made to corres- 
 pond with it. It has been stated that these heat 
 ribs produce no useful effect unless they project into 
 the inner casing, to which they are intended to carry 
 the heat, as well as the outer space from which they 
 borrow the heat. This, of course, can only be carried 
 into effect in the case of the cylinder-cover. But 
 this point has been decided by Mr. Halpin, the in- 
 ventor of the ribbed cylinders. In a letter received 
 
128 THE ABUSE OF THE STEAM-JACKET 
 
 from Mr. Halpin, the following remarks occur : " I 
 have subsequently made several experiments, and find 
 that, by perfect ribbing, the amount of heat transmitted 
 in the ribbed cylinders is 3'28 times that transmitted 
 in the plain cylinders." Fig. 49 shows a section of a 
 low-pressure cylinder liner and valve-chest, the whole 
 of which is inclosed within a steam casing. We look 
 on this system of steam-jacketing as the most efficient 
 in existence. Mr. Halpin carried out some experi- 
 ments with a small stationary compound engine, both 
 the cylinders of which were got up in the style shown : 
 the results of the trial was without a parallel, prov- 
 ing beyond a shadow of a doubt the substantial benefits 
 to be derived from the application of real steam- 
 jackets to the cylinders of steam-engines. Fig. 48 
 shows the end view of a small stationary engine 
 cylinder. Fig. 43 shows the barrel provided with heat 
 ribs also. 
 
 9. In large engines of short stroke, not only should 
 the covers be jacketed, but the piston should be heated, 
 for it is a ivell-knovm fact that the jacket round the 
 barrel is powerless to extend its influence into a great 
 body of steam,. In these cases the covers and pistons 
 expose a larger area of heating surface if fitted with 
 steam than the circumferential jacket does.^ It has 
 been said : " The action of a steam-jacket in securing 
 economy is greater as the diameter of the cylinder is 
 smaller. Some marine engines have been fitted with 
 
 * Mr. Lavington E. Fletcher recently said : " He was of opinion 
 that steam was very much misused, from the fact that the cylinders 
 and receivers, &c., were not sufficiently steam -jacketed, and the boiler 
 pressure maintained in the jackets during the whole time the engine 
 was at work ; they should not be content with having only the sides 
 of the cylinders jacketed, but also the ends, which, in his opinion, was 
 equally important. This question of jacketing must receive attention 
 as the pressure of steam used increases." 
 
JACKETED CYLINDER-COVERS 129 
 
 steam-jacketed pistons, the stearn being admitted by 
 a sliding tube. 
 
 In a large marine engine we noticed sometime ago, 
 the pistons were provided with balancing cylinders 
 fixed to the bottom covers of each cylinder. The 
 balancing cylinders had hollow piston-rods through 
 which steam was admitted to the interiors of the main 
 pistons, while the effective pressure of steam on the 
 under sides of the balancing pistons was increased by 
 the upper ends of the balancing cylinders being placed 
 in communication with the condensers.^ 
 
 10. With regard to jacketed cylinder-covers, the ut- 
 most care must le bestowed 
 on their steam-supply and 
 drainage, for nearly all the 
 jacketed covers are de- 
 fective in this matter. 
 In the majority of cases 
 these communications sim- 
 ply consist of a few 
 holes drilled through the 
 ends of the cylinder into 
 
 the jacket, and similar Fig. 54. Faulty jacket-drain. 
 
 holes to correspond drilled 
 
 opposite them in the faces of the covers (as described 
 
 from practice at p. 119.) 
 
 There should always be some provision made for 
 preventing these holes becoming choked up with red 
 lead when the cover-joint is being made, for, unless 
 this be attended to, they will undoubtedly soon 
 become obstructed ; few engine-drivers would take 
 
 * Mr. John Phillips said : " Some years ago he remembered being 
 told of some vessels that had been wanting a little in speed, and their 
 speed had been increased to the required amount by simply putting 
 boiler steam inside the pistons." 
 
 I 
 
130 
 
 THE ABUSE OF THE STEAM-JACKET 
 
 the trouble to keep them clear, and no one could 
 guarantee to always keep them open, no matter how 
 carefully the joint was made. One very simple plan 
 is to provide a plug opposite each communication hole, 
 which may, before the joint is made, be taken out, and 
 a bar or bolt passed through it into the communica- 
 tion hole at the time that the joint is being made. 
 
 Fig. 55. Jacket drain-pipe. 
 
 Eed lead is thus prevented from entering the holes and 
 of obstructing the passage of both steam and water. 
 
 Fig. 57 shows the arrangement described. A second 
 plan is also inserted, by fig. 56, which consists of a 
 short piece of tube screwed into the cover. If cylinder- 
 cover joints are made with red lead, some provision of 
 this kind is necessary. When the engines are new, 
 
CLEARANCE SPACES 
 
 131 
 
 the joints are made with brown paper, or they are 
 carefully faced and made with a little tallow only : 
 the precaution then becomes unnecessary. Figs. 43 
 and 51 show methods of supplying jacketed cylinder- 
 covers with steam : their proper drainage is also 
 illustrated. 
 
 11. There is room for improvement in most steam- 
 engines in the matter of the clearance, which should be 
 reduced to a minimum. The steam-ports should be 
 kept as short as possible. By making the steam- 
 
 Fig. 56. 
 
 57. 
 
 Jacketed cylinder-covers. 
 
 chest longer than the cylinder, as shown by fig. 39, 
 the steam-ports in many engines can be kept straight 
 and very short. It is owing to this reduction of the 
 clearance in the Corliss engine, which has, without 
 doubt, contributed in no small measure to the econo- 
 mical working and success of this excellent type of 
 engine. 
 
 Another valuable feature of this type of engine 
 consists in having separate steam and exhaust ports, 
 for Mr. Joule has pointed out that the almost universal 
 
132 
 
 THE ABUSE OF THE STEAM-JACKET 
 
 practice of making the steam enter and leave the 
 cylinder by the same port tends to the waste of heat, 
 especially with high rates of expansion. 
 
 Few engines at one time had separate steam and 
 exhaust ports, but it is becoming a general practice to 
 have separate admission and exit ports, the latter 
 being, as a rule, at the bottom for efficiently draining 
 
 Fig. 58. Cylinder for Compound Tramway Locomotive, by 
 Messrs. Aveling & Porter.* 
 
 the cylinder during the exhaust. Fig. 19 is a good 
 arrangement. Figs. 33, 35, 36, 43, arid 52 show 
 sections of Corliss cylinders with short ports. By 
 placing the valves in the cylinder-covers this waste 
 in port space is certainly reduced to the utmost limit, 
 as shown by figs. 33 and 52, but the arrangement 
 possesses some disadvantages, which need not be 
 mentioned here. 
 
 * We are indebted to Engineering for the illustrations, fig. 58 
 and fig. 59. 
 
CLEARANCE SPACES 
 
 133 
 
 In many stationary engines the steam-ports and 
 slide valve- chests are made of an undue size, in order 
 to bring the slide-rods in a line with the eccentrics 
 on the crank-shaft. The position of the eccentrics is 
 ruled by the length of the main bearing, the thickness 
 of the crank-arm or disc, and the length of the crank- 
 pin. Fig. 37 shows the fault referred to. 
 
 The large steam-chests on many steam-engines 
 
 Fig. 59. Cylinder for Compound Tramway Locomotive, by 
 Messrs. Aveling & Porter. 
 
 are badly protected against the radiation of heat. 
 Fig. 52 shows an effective method of protecting the 
 cylinder. 
 
 In a trial of stationary engines some years ago, 
 one maker very wisely filled up the useless space of 
 the slide-valve box with blocks of hard wood. Some 
 of the little vertical engines used for electric lighting 
 and other purposes have enormous clearance spaces. 
 
134 THE ABUSE OF THE STEAM-JACKET 
 
 These engines use high-pressure steam, and run at very 
 high speeds : need we wonder, therefore, at their waste- 
 fulness ? See Professor Unwin's report on the Ply- 
 mouth Trials of Small Steam-Engines, given in Chapter 
 III. 
 
 12. The last but not least part of our duty is to 
 emphatically denounce all steam-jackets that are left 
 exposed to the atmosphere or unlagged : indeed it 
 should be, amid all our present knowledge, totally 
 unnecessary to mention this as one of the needful 
 conditions of successful jacketing ; but, much as we 
 regret it, we are bound to confess that there are many 
 engines turned out of hand with steam-jacketed 
 cylinders unlagged, chiefly on low-priced portable and 
 vertical engines, intended in not a few instances for 
 out-door service. Need we wonder that some makers 
 say that they have tried the jacket, and find very 
 little difference in the coal consumption during the 
 test of an engine with the cylinder steam-jacketed 
 and the surface of the jacket left totally exposed, and 
 one with the cylinder unjacketed, but carefully clothed 
 and lagged over the whole surface ; for, what is gained 
 inside of the cylinder by the application of the steam- 
 jacket, is partly counteracted by the loss of heat 
 radiated from the unlagged jacket. Eadiation of heat 
 from the cylinder and other parts of the engine is a 
 very direct source of loss. Some experiments, made 
 by Mr. D. K. Clark, show that, in the case of exposed 
 cylinders, the loss from this cause may rise to as 
 much as 50 per cent. It is impossible to wholly 
 prevent escape of heat ; but, by casing or lagging the 
 cylinder and steam-pipes with an efficient non-con- 
 ducting material, the loss, we are told, may be reduced 
 to as little as 2 per cent. 
 
 We have dealt very fully with cylinder clothing 
 
CYLINDER LAGGING 
 
 135 
 
 compositions elsewhere, but we may imitate, with 
 advantage and profit, an American example of effective 
 cylinder clothing. We refer to the 1400 horse-power 
 Corliss engine at the Philadelphia Exhibition. The 
 
 Fig. 60. 
 
 cylinders were steam-jacketed and covered with hair 
 felting and lagging, the former f-inch thick, the 
 latter 1-inch thick; outside this there was an air- 
 space |-inch thick between it and the polished iron 
 casing. 
 
136 
 
 THE ABUSE OF THE STEAM-JACKET 
 
 By fig. 42 we illustrate the method of protecting 
 the steam-jacketed Cornish engine cylinder. 
 
 The steam-jacket is surrounded by another casing 
 of wood, the space between the two being filled with 
 some bad conductor of heat, such as sawdust, ashes, 
 or slag-wool. The whole is inclosed by a casing of 
 brickwork, or by an air-tight cavity formed by 
 building a thickness of brickwork at a few inches 
 
 Fig. 61. Compound traction engine cylinder. 
 
 distance, which is plastered on the outside and covered 
 with wood panelling. The cylinder cover and bottom 
 are also protected from the cooling influences of the 
 air ; the former being fitted with a false cap inclos- 
 ing a thick layer of non-conducting composition. A 
 small branch pipe, shown by the illustration, supplies 
 steam to the stuffing-box. 
 
BRIGHT SURFACES 137 
 
 The following sentence bearing on this subject is 
 quoted from Hopkinson's Guide : " To prevent the 
 escape of heat by radiation, it is only necessary that 
 the cylinder, and all parts of the metal which receive 
 heat from the stearn by contact or conduction, should 
 have a clean metallic surface. Whoever has been 
 much about steam-engines will have often felt that a 
 dirty cylinder and engine generally, seemed to make 
 the engine-room insufferably hot. Such is really the 
 fact. If any one should doubt the statement that a 
 clean polished metallic surface radiates less heat than 
 a black and dirty one, let him try the experiment, 
 and he will doubt no more. Cleanliness, therefore, is 
 the handmaid of economy, and, at the same time, 
 pleasant withal to look upon." 
 
 With these facts before us, it is our duty, previous 
 to accepting any of the startling figures said to be 
 the results of a practical and accurate engine test for 
 and against steam-jacketing, to ascertain for ourselves : 
 (1) That the engineers and attendants engaged in 
 the test understand the function of the jacket, and 
 know how to use it, should it be so arranged that its 
 action may be interfered with by them. (2) That 
 the so-called jacket is really an efficient steam-jacket, 
 possessing all the necessary requirements for obtaining 
 the best possible results ; in fact, it is a farce to merely 
 say that the cylinder is steam-jacketed, but exact 
 sectional drawings of the cylinder, and complete 
 description of the supply and drainage pipes should be 
 given, for, without such information, the publication of 
 a lot of tables and figures teach nothing, and are of 
 no practical value whatever. 
 
 Whenever the steam-jacket has been well applied 
 and properly tested, its utility has been proved beyond 
 a doubt, but, in too many instances we fear, some of 
 
138 THE ABUSE OF THE STEAM-JACKET 
 
 the miserable counterfeit jackets we have alluded to, 
 instead of the real article, has been tried, which ex- 
 plains the mistaken notions in vogue as to its utility, 
 and the nonsense that is occasionally expressed in 
 some quarters respecting it. 
 
 In this chapter we have alluded to several steam- 
 saving appliances that are absolutely needed to make 
 all steam-jacketed cylinders complete, and thoroughly 
 effective : such as steam-collectors, steam-traps, re- 
 turn steam-traps, dry steam generators, &c. More 
 particulars of these fuel-economising agents are given 
 in the Appendix. 
 
CHAPTEK VI. 
 
 THE ABUSE OF THE STEAM-JACKET continued. 
 Defective Construction. 
 
 LET us see how the steam-jacket may be abused by 
 mal-construction. 
 
 It has been our lot to have had (in addition to the 
 designing of new engines) the superintendence of 
 repairs to numerous portable, traction, and other 
 engines for some years, during which time we 
 have had a favourable opportunity for noticing the 
 weak points in the construction of the engines of 
 different makers ; and it would be an easy matter to 
 place on record the description of some very curious 
 steam-jackets that have during this time been dis- 
 covered ; but such a catalogue of makeshifts and 
 mistakes would not answer any good purpose were 
 they recorded. We have chosen out of a great 
 number, three cases under this head, to show how bad 
 workmanship may interfere with or destroy the utility 
 of the jacket ; the first is the record of a cylinder 
 having a flaw in it, attributable to incompetent mould- 
 ing ; the second case is the result of carelessness 
 during the erection of an engine ; while the third is 
 an account of a badly-turned and bored cylinder liner 
 and jacket, which were made in separate castings, 
 and, when put together, being a very indifferent fit, did 
 
140 THE ABUSE OF THE STEAM-JACKET 
 
 not constitute a tight joint between the two when 
 tested under steam. 
 
 It is well known by practical men that there is 
 considerable difficulty in procuring a sound casting 
 from the foundry of a cylinder when cast with a 
 steam-jacket round it : hence, to reduce this risk, the 
 walls of the cylinder are made excessively thick : some 
 makers of portable engines use a cast-iron wall of 
 quite an inch thick for a cylinder but 9 -inch bore. 
 We need not be surprised to learn that these users of 
 thick cylinder walls are somewhat disappointed in the 
 results arrived at during the use of such jackets : for 
 it has often been affirmed that these thick walls 
 seriously interfere with the efficiency of the steam- 
 jacket, as we have already alluded to. 
 
 The Engineer says that : " The steam-jacket is use- 
 less if the walls of the cylinder are so thick that heat 
 cannot be freely transmitted from the steam outside to 
 the steam inside the fault lies not in the jacket, but in 
 the manner of making it : we must not condemn steam- 
 jackets, however, because of incompetent moulders." 
 In cases where the jacket and the cylinder are cast 
 together, and the walls and partitions are of varying 
 thicknesses, and, particularly, when there are any 
 lumps of metal left in corners and other parts of the 
 cylinder, the partitions are very likely to be " spongy," 
 caused by the " drawing " of the metal during cooling ; 
 in some instances, a place of this sort is not detected 
 until the engine is tried, or has been at work some 
 time, when the flaw has commenced to allow steam to 
 leak from one part of the cylinder to another, some- 
 times blowing from the jacket into the steam-chest or 
 the supply-ports, which, of course, seriously interferes 
 with the working of the engine. The only remedy in 
 this case, and the one very often resorted to, is to cut 
 
FAULTY CYLINDER CASTING 141 
 
 off the steam supply from the boiler to the jacket. 
 Here is the record of a troublesome steam-jacketed 
 cylinder of this description being doctored, which we 
 heard from the lips of the facetious party who effected 
 the " cure," as he was pleased to call it ; and, as we 
 entertain not a doubt respecting the accuracy of the 
 story, it will serve as a case in point for this part of 
 the subject. A new eight-horse portable engine, made 
 by a small firm, was sent out to a customer, having a 
 faulty place in one of the walls of the cylinder between 
 the steam-jacket and the slide valve-chest, which had 
 either not leaked during the trial on the works, or it 
 had not been discovered ; but, unfortunately, very 
 soon after the engine was put to work, it began leaking 
 so rapidly that it was impossible to stop the engine 
 when required, as there was provided no means of 
 shutting off the steam from the jacket round the 
 cylinder. 
 
 Complaints were at once despatched to the makers, 
 who sent out a fitter " to look to the stop-valve gear," 
 and ascertain the cause of the annoyance, and put 
 the engine to rights ; he soon found out that the stop- 
 valve gear was in order, and that the steam gained 
 access to the valves above the stop-valve through this 
 faulty place in the cylinder partition. 
 
 After dropping the steam, taking off the steam - 
 chest cover, and convincing himself that no patch 
 could be put over the flaw, an idea (of which he is 
 ever proud) at once suggested itself, and he took the 
 cylinder off the boiler to put his happy thought into 
 practice. Now the jacket of this cylinder was supplied 
 with steam by means of a piece of 1-inch piping 
 screwed through the arch plate of the boiler into the 
 bottom of the jacket. By a little manoeuvring, he 
 managed to take out this pipe from the inside without 
 
142 THE ABUSE OF THE STEAM-JACKET 
 
 the engine-driver, who was helping him, noticing the 
 act; he then told this assistant that he had found 
 out the cause of all the trouble, or, to use his own 
 words, " I have found out a ' mare's nest,' " pointing to 
 the hole through which the supply pipe had been 
 screwed. " This hole has no business to be here, and 
 must be stopped up ; " his ignorant and confiding 
 mate nodding assent. 
 
 He screwed and ri vetted a plug into it, re-made 
 the cylinder joint and the connections, steamed the 
 engine, pronounced her cured, then took his leave of 
 the driver, who, no doubt, is just as satisfied with his 
 engine with a " dummy " jacket round the cylinder as 
 he was with a real one, seeing that he has always 
 been totally unaware of the jacket's existence, much 
 less its use. 
 
 So long as this jacket remains as an air-space, it 
 would be of some slight service in checking the radia- 
 tion of heat from the working steam within the 
 cylinder ; but it is very probable that some of the 
 steam, finding its way through the flaw from the 
 valve-chest into this jacket space, would be condensed ; 
 in the course of time, therefore, the water resulting 
 from this condensation would fill the jacket up to the 
 level of the flaw, there being no means of escape at 
 the bottom. It is needless to mention that the jacket 
 in this state, viz., half filled with water, instead of 
 being of some slight service, would be a positive evil. 
 
 Most of the jackets that are abused by incompetency, 
 laziness, or carelessness, are rendered useless, owing to 
 the accumulation of water in them, the water-jacket 
 being by far the commonest type. 
 
 Here is the record of another type of jacket. The 
 outside casing around one of the cylinders of a double 
 portable engine, by another maker, was accidentally 
 
BADLY-FITTING LINER 143 
 
 cracked during the erection of the engine (cracked 
 cylinders are evidently not solely confined to the 
 engines of Her Majesty's Navy), and, as a patch could 
 not be put on the outside because the cylinders of 
 this firm are not arranged for lagging lagging being 
 an admirable cloak for hiding such like "bodges," 
 notwithstanding its utility, the following plan was 
 adopted in this dilemma; the jacket space was filled 
 up and rammed with rust cement through the core 
 holes in the end, and the pipe for supplying the jacket 
 of this cylinder was, like the one in the last case, 
 plugged up, to prevent the possibility of any steam 
 leaking through the cement and out at the crack. 
 
 We have heard of hot-air jackets, smoke-jackets, 
 water-jackets, exhaust-jackets, and steam-jackets, but 
 this is a novel one, viz., a cement-jacket, a makeshift, 
 truly, of doubtful utility. 
 
 Another instance of a leakage from the jacket to 
 the cylinder, of rather a different nature, occurred on 
 a large horizontal fixed engine made by a very small 
 firm. The cylinder and bush were separate castings, 
 the latter turned and the former bored to suit, but, 
 owing to incompetency, or great carelessness on the 
 part of the turner, the joint, after the bush was 
 inserted, leaked all round when under steam. The 
 cylinder was then put under a rusting process, or, 
 to use the workmen's term, it was " pickled " in sal- 
 ammoniac and water for some days ; but all to no 
 purpose, for, when steamed again, it leaked into the 
 cylinder at each end. The engine was, we are told, 
 sent away in this plight, for, unfortunately no 
 diagrams were taken, so that this carelessness was not 
 revealed to those who might have condemned such 
 mal-construction, and have also prevented the engine 
 being sent away in this manner. 
 
144 THE ABUSE OF THE STEAM-JACKET 
 
 Eef erring to the trials carried out on the steam- 
 vessel " Meteor," Mr. List said : " Steam-jackets were 
 necessary. He warned our engineers to see that the 
 liners were steam tight, as cases have occurred in 
 which the liners of marine engines did not make a 
 good joint in the casing. Such a piece of bad work- 
 manship would neutralise any advantage that might 
 accrue from the steam-jackets. 
 
CHAPTEE VII. 
 
 THE ABUSE OF THE STEAM-JACKET continued. 
 Inattention on the Part of the Engine-Driver. 
 
 THE steam-jacket may be abused by carelessness on 
 the part of the attendant, whenever its right action 
 depends on his control. In large engines of one or 
 two types the condensed steam from the jackets is 
 generally carried away by means of a pipe having a 
 cock in it, placed within the reach and under the 
 control of the engine-driver, which is an unsatisfactory 
 arrangement, because the chances are that the cock 
 may not be opened at all, or not nearly often enough ; 
 an ignorant driver thus having it in his power to 
 transform an efficient jacket into an efficient con- 
 denser, the result causing an enormous waste. It is 
 very essential that the supply and drain pipes for the 
 jackets should be so arranged that it is quite un- 
 necessary for the engineer to interfere with them, or, 
 as some one recently put it, " quite independent of a 
 lazy or careless engineer." It is equally important 
 that the opening and closing of these pipes should not 
 be left to the discretion of the attendant, because of 
 his love of meddling with, and experimenting upon, 
 every detail of the engine under his charge ; for, in 
 these individuals, as in most other mechanics, where 
 there is a minimum supply of knowledge, there is 
 
 K 
 
146 THE ABUSE OF THE STEAM-JACKET 
 
 generally to be found a maximum amount of conceit, 
 and no sooner is an engine placed under their charge 
 than they find out a number of imaginary defects 
 and details requiring improvement : this tampering 
 with the engines very often ends in disaster.^ 
 
 The following is an amusing instance, illustrating 
 this trait in their character, given in a little book 
 entitled : The Engine Room, Who should ~be in it, 
 &c., by an Old Hand, which we quote, although it is 
 a slight digression. 
 
 " When at Galatz, in 1867, a boat was sent from 
 
 the I , of N , with a request from her captain 
 
 to ours to allow me to go on board of her, as they could 
 not start the engines : our captain being agreeable, I 
 went. On getting on board the captain introduced 
 me to the engine-room, where, in the faces of all, was 
 a look of half bewilderment. The captain, being a 
 true representative of the north country vernacular, 
 said to the chief : ' Winna she gan yet ; what's wrang 
 
 * Since writing the above remarks respecting the omission of duty 
 by the engine-driver, and the delight he generally evinces for trying 
 his hand at the improvement of parts, &c., causing steam-jackets 
 either to be neglected altogether or else shut off, we have read Sir 
 Frederick J. Bramwell's two excellent lectures on "The Steam- 
 Engine," Macmillan, wherein he mentions the engine-driver's power 
 in many cases to frustrate the designer's intentions, and, consequently, 
 to waste his employer's fuel. Here is the sentence referred to : " I 
 do not think that the economy of the compound engine really lies in 
 its principle, but that its economy in practice arises from another thing 
 altogether, and that is this, that by making a double cylinder engine 
 you put it out of the power of an ignorant engine-driver to do away 
 with that which you want high expansion ; he must get high expan- 
 sion ; he is compelled to use it whether he likes it or not ; whereas, 
 with the single cylinder expansive engine, he has the power to follow 
 the dictates of his own ignorance, and, as a matter of observation, I 
 have hardly ever seen such an engine left to the control of an engine- 
 driver but it invariably worked at the lowest possible grade ; and, as I 
 have said, I believe that this withdrawal of control is, to a large extent, 
 the secret of the success of the compound cylinder engine." 
 
MEDDLESOME ENGINE-DRIVER 147 
 
 wi' her ? ' ' She's a' het,' says the chief. ' Dinna ye 
 think the improvement hes out te de wi't ? ' says the 
 captain. ' Na, na,' says the chief, ' it hes nout te de 
 wi't, she's fu' o' san.' During this colloquy the 
 reversing wheel was turned repeatedly, but to no 
 purpose. I asked the captain what improvement he 
 alluded to ; he told me that his engineer had got some 
 undefined notion from the engineer of another steamer, 
 that the only way to save his coals was to ' gie her 
 sma' steam, 5 and that he had done something ' wi' the 
 slides,' but what that was he could not say. It was 
 proposed by the captain, at my suggestion, to lift the 
 casing cover. What a look of offended dignity the 
 chief assumed ! Much against his will, the steam was 
 blown off, &c., &c., and the cover lifted, when the 
 reason of the engines not starting was at once 
 apparent. Three-quarters of an inch of wrought 
 iron had been pinned (and very badly) on to the 
 ends of each slide valve ! I asked the chief if he had 
 done anything with the eccentrics. ' Dune out wi't 
 sheaves ? Na, na, they're a' reet.' The economical 
 pieces were taken off, and she proceeded the following 
 day. I learnt this chief was ' a converted fireman.' " 
 
 Our steam-ship companies have vastly improved 
 their machinery, adopting compound engines with 
 steam-jacketed cylinders. The steam-supply and the 
 drainage-pipes of these jackets are fitted with cocks. 
 But, while they have taken care to introduce first-rate 
 machinery into their vessels, they have entrusted these 
 engines to the tender care of drivers who, whatever 
 knowledge they possess of marine engines and 
 machinery in general, display the utmost lack of 
 information respecting the steam-jacket ; and the 
 following accounts, while showing how they mani- 
 pulate the drainage cocks of the jackets placed under 
 
148 THE ABUSE OF THE STEAM-JACKET 
 
 their charge, unmistakably reveal this lack of know- 
 ledge. 
 
 One or two authorities on marine engineering have 
 expressed doubts as to whether the jackets on board 
 our steam-vessels received proper attention at sea. 
 To confirm these doubts a writer in Engineering gives 
 the results of his observations, extending over several 
 years, in connection with the steamers of a large com- 
 pany,^ from which we gather the following particulars. 
 Mr. Coath says : " My interest in the use and abuse 
 of the steam-jacket having been powerfully aroused 
 some years ago, I have availed myself of every 
 opportunity since for observing in how far the benefits 
 appertaining to the use of a steam-jacket are actually 
 obtained in practice ; or, in other words, in how far 
 steam-jackets are ' used ' or ' abused.' From my 
 notes I find that up to date my observations extend 
 to twenty-three steamers, in which, with two 
 exceptions, I find the steam-jacket more or less 
 abused, and, in some cases, to such an extent as to 
 render its existence a cause of positive loss, so that, 
 under the circumstances, it would have been better 
 not to have applied it at all. 
 
 " My modus operandi has been, in course of conversa- 
 tion with a chief, or naval engineer, to elicit how he 
 manages ' his jacket.' " The results of these ' observa- 
 tions are briefly as follows : 
 
 In thirteen steamers he found the drain-pipe full open 
 to the condenser, and the steam-supply cock to the 
 jacket partly open. 
 
 In three steamers the jackets were only used on 
 starting to warm up the cylinders, and, when the 
 engines were well under way, the steam-supply was 
 totally closed, and the outlet opened to the condenser. 
 
 * Mr. D. D. Coath in Engineering, 7th July 1882. 
 
WATER-JACKETS 149 
 
 In two cases the inlet was left wide open, and the 
 drain-pipe kept closed, and the condensed steam was 
 blown out once a watch. 
 
 In three instances no trouble was taken with the 
 jacket, because the engineer-in-chief could not see 
 what difference it made. 
 
 In two steamers the engineer said : " I work with 
 the jacket steam full open, and regulate the drain so 
 as to as nearly as possible keep the jacket free from 
 water without wasting steam by passing through." 
 
 It will be seen from the above remarks that, in 
 about 70 per cent, of the cases observed, the existence 
 of the jacket is a positive evil, indeed, in the first 
 cases named, this evil amounts to surrounding the 
 cylinder by the condenser, for the so-called steam- 
 jacket virtually forms part of the condenser.^ In 
 the third case it amounted to the partial use of a 
 water-jacket. 
 
 The following paragraph is quoted from a letter, 
 signed A. M., in Engineering, for 10th April 1874. 
 " Those engineers who advocate the disuse of steam- 
 jackets do it merely to save trouble to themselves, 
 never thinking of the amount of money they cost 
 their owners ; so long as the engine gives no bother, a 
 few revolutions is nothing to them. We heard of an 
 amusing instance the other day of an engineer, when 
 asked as to his steam-jackets, answered that they 
 were shut off to keep the engine-room cooler ; and of 
 another, when the maker of the engines visited the 
 engine-room, he found the jacket space filled with 
 water, doing the duty of a condenser on a small scale. 
 The maker of the engines put the question : Of what 
 use is my spending so much money on steam-jacketing 
 
 * See Mr. Bryan Donkin's experiments, recorded in the next 
 chapter. 
 
150 THE ABUSE OF THE STEAM-JACKET 
 
 when owners will not see the intention carried out, 
 although it is for their own benefit ? " 
 
 It is perfectly astounding to think that the ridicu- 
 lously simple matter of attending to the steam-jacket's 
 proper drainage should be so ignorantly tampered with 
 by so-called engineers of the present day. By this 
 lack of knowledge, or meddlesome interference on the 
 part of engine-drivers, the designer's purposes are 
 frustrated, causing the intended steam-jacket to be 
 transformed into a water-jacket or a surface-condenser, 
 and resulting in such an extravagant waste of steam, 
 which could not be equalled by the neglect or the 
 mismanagement of any other detail of the steam- 
 engine. 
 
 The steam-jackets of our marine engines, by having 
 their drain-pipes imperfectly fitted and interfered 
 with, instead of conducing to economy are made to 
 act as wasteful dissipators of steam, the amount of 
 such loss being beyond computation. 
 
 One writer says : " I should advise those who 
 have steam-jackets round the cylinders of their engine, 
 to see that the drains and supply are properly placed, 
 that is to say, independent of a careless or lazy 
 engineer. 
 
 Messrs. E. Napier & Son take the steam from the 
 boilers, and drain to the boilers ; the cocks or valves 
 are opened when the ship leaves the dock or wharf, 
 and are not closed until arrival at destination." Mr. 
 Eich says : " Purchasers and users of steam-engines 
 frequently did not appreciate the advantages to be 
 derived from steam-jackets, and would not incur the 
 extra cost; and, even when steam-jackets were supplied, 
 they were too often tended by engine-drivers, who, 
 from ignorance or negligence, failed to realise the 
 possible advantages. Indeed, from personal observa- 
 
INCOMPETENT DESIGNING 151 
 
 tion, he believed that not even one-half of the steam- 
 jackets in existence were worked efficiently."^ 
 
 We have pointed out the manner in which the 
 steam-jacket has been rendered of little or no value 
 on account of faulty designing, defective construction, 
 and inattention. It would seem, judging by past 
 experience, that incompetent designing is by far the 
 most common cause of the inefficiency of the steam- 
 jacket. If any one will take the trouble to examine 
 the steam-jacket on various classes of engines, he will 
 find more examples of wretched scheming than could 
 be found connected with any other detail of the steam- 
 engine. From this it is self-evident that the require- 
 ments of efficient jacketing are rarely understood, but 
 this ignorance may be partly accounted for from the 
 fact that little or nothing has been written on this 
 part of our subject : the steam-jacket has been men- 
 tioned by various writers on the steam-engine, there 
 has also been much written at various times respecting 
 its utility but very little has been said concerning 
 the requirements necessary to render it of service : in 
 other words, no one has, to our knowledge, stated how 
 the steam-jacket should be arranged and applied. 
 
 In order, therefore, in some measure to supply this 
 want, in Chapter V. we have enumerated many of the 
 chief points of importance which it is necessary should 
 be strictly attended to, both by Designers, Manu- 
 facturers, and Owners of steam-jacketed cylinders, 
 in order to produce and keep them in efficient work- 
 ing condition, so that the object for which they are 
 applied, viz., the economy of fuel, may be fully 
 realised. 
 
 As the greatest responsibility rests with the 
 
 * "Engines for Pumping:" paper read before the lust, of Civil 
 Engineers by W. E. Rich, Esq., M.I.C.E., 1884. 
 
152 THE ABUSE OF THE STEAM-JACKET 
 
 draughtsman, how very important it is that he should 
 endeavour to thoroughly and conscientiously work out 
 the details of engines, ever aiming at the highest 
 results, remembering that every detail of machinery 
 illustrates the mind, and, to some extent, the character 
 of the designer ; yes, to engineers, these parts of 
 engines express more intelligibly than words can even, 
 the designer's thoughtfulness and wisdom, or his haste 
 and ignorance ; the smallest detail unmistakably 
 exhibits every evidence of care that has been bestowed 
 in the drawing office on its production. Let us all, 
 therefore, aim at perfect efficiency and complete 
 success. 
 
 " 'Tis not in mortals to command success ; 
 We will do more deserve it." 
 
 By careful designing we may, to a large extent, 
 perform our part of the " duty that devolves upon 
 scientific mechanical men, viz., that of preventing the 
 scandalous waste of fuel that now, alas, too frequently 
 occurs." 
 
CHAPTEE VIII. . 
 
 PRACTICAL PROOF OF THE EFFICIENCY OF THE 
 STEAM-JACKET. 
 
 IT is by actual experiments alone that the value of 
 the steam-jacket can be shown, for very little depend- 
 ence can be placed upon the results arrived at by 
 theoretical investigations, this being unfortunately 
 one of those questions where figures may be made to 
 represent almost anything the theorist pleases. 
 
 Watt did not ascertain the value of the steam- 
 jacket by calculation, but by actual tests; and, strange 
 to say, the very first theory raised against its use, viz., 
 Tredgold's, proved to be incorrect. 
 
 Numerous experiments have been made during the 
 last fifty years on all classes of engines, and, whenever 
 engines have been accurately tested with and without 
 steam in the jackets, the results invariably prove the 
 economy of thorough steam-jacketing. 
 
 It has often occurred that, when the jackets of 
 steam-engines have been shut off for a short time by 
 accident or for repairs, it has been necessary, in order 
 to keep up the speed of the engine, to alter the 
 expansion valve, so as to give a later cut-off, and, 
 consequently, the boilers have had to be fired harder 
 to keep up the steam. We could give numerous cases 
 of this kind, proving the value of the steam-jacket, 
 
154 THE EFFICIENCY OF THE STEAM-JACKET 
 
 when no such proof was sought or expected to be 
 realised. 
 
 Watt, in his early practice, discarded the steam- 
 jacket for a short time, but resumed it again, because 
 he found its discontinuance caused a perceptible waste 
 of fuel. It is a well-known fact that, in Cornwall, any 
 attempt made to discontinue the use of the steam- 
 jacket round .the cylinder has been attended with a 
 palpable loss of power, although the radiation of heat 
 seemed to be effectually prevented by the use of the 
 best non-conducting substances. " Trevithick stated 
 that there was 40 per cent, increase in the duty of 
 Watt's engines, when worked expansively, from putting 
 a steam-jacket on the cylinders." * 
 
 In some experiments on a small-beam condensing 
 engine at Mr. Penn's flour-mill at Lewisham, in 1849, 
 Mr. Farey said Mr. Penn's comparative trials with 
 and without steam in the steam-case had shown the 
 advantage of supplying steam around the cylinder to 
 be very considerable, although the steam pressure 
 used in this instance was only 6 Ib.t Mr. Edward 
 Humphries conducted some experiments at Woolwich 
 Dockyard nearly forty years ago, in which the weight 
 of feed-water used per horse-power was carefully 
 noted, which showed that there was a positive loss in 
 attempting to work with any degree of expansion 
 in the unjacketed, slow-going, large cylinder geared 
 engines in use in the British Navy at that time, and 
 adopted in the American Navy up to a more recent 
 date. At a meetjuig of the Manchester Association of 
 Engineers, held a few years ago, a paper was read on 
 the " Steam Jacket," and, during the discussion, the 
 
 * Scott-Russell on The Steam-Engine, 1841. 
 
 t Mr. Bryan Donkin in the discussion on Rich's paper on " Pump- 
 ing Machinery," read before the Institution of Civil Engineers. 
 
VALUE OF THE STEAM-JACKET 155 
 
 following fact was related by one of the members : 
 " When the steam was turned off from the jacket of 
 an engine, used by the Fairbairn Engineering Company, 
 they found that they lost power, and the boilers would 
 not supply sufficient steam, the stokers were unable to 
 keep up the steam ; when the jackets were turned on 
 again, the engine and boilers easily performed their 
 allotted task." 
 
 The following extract from a letter from Mr. 
 Pinchbeck appeared in Engineering, which clearly 
 shows the advantages of steam-jacketing : " It so 
 happened that the steam-trap connected with the 
 steam-jacket required repairing, and, to do this, the 
 steam had to be shut off: while these repairs were 
 going on, I found the consumption of coal per day 
 increased from about 14 cwts. to nearly 20 cwts. ; I 
 also found the engine incapable of performing the 
 same amount of work as it did when the steam-jacket 
 was in use ; I had, therefore, to alter the cut-off valve 
 to admit more steam. As soon as the repairs were 
 effected, the steam was re-admitted into the jacket, 
 upon which the consumption fell again to 14 cwts. per 
 day after the expansion valve had been put back to 
 its previous position. This experiment left no doubt 
 in my mind as to the economical advantage of the 
 steam-jacket, and it will take a very great deal of 
 argument to create a doubt that I am mistaken." 
 
 The following is quoted from Hopkinson's Engineers' 
 Guide : " If the steam be for a short time shut off 
 from the jackets of the engines of Sir T. Salt, Bart., 
 and Co.'s, of Saltaire, unknown to the stokers, they 
 discover by the heavier firing required that something 
 is amiss, and soon begin to inquire what is the matter." 
 
 Although these instances show the advantages of 
 steam-jacketing, and are practical proofs of its efficiency, 
 
 OF THB 
 
 UNIVERSITY 
 
 , 
 
156 THE EFFICIENCY OF THE STEAM-JACKET 
 
 yet we will now give the results of actual and accurate 
 trials of engines of every type, which furnish more 
 weighty testimony in favour of thorough steam-jacketing. 
 
 Combe, a French engineer, as far back as 1843 
 appears to have been one of the first to make a careful 
 feed-water experiment on a small condensing engine, 
 with a cylinder 15f-inch diameter. The result was 
 an economy in feed-water of 42 per cent., due to this 
 cylinder being steam-jacketed. Expansion was about 
 20 to 1 ; pressure of steam 57 Ibs.* 
 
 Mr. Him, about 1854, made some experiments on a 
 compound-condensing beam-engine, indicating about 
 104 horse-power and 80 horse-power, with and 
 without steam in the jacket, and found an economy in 
 the feed-water of 24 per cent, in favour of using steam 
 in the jacket. Expansion, 4 to 1 ; the steam pressure 
 was 60 Ibs. per square inch.t 
 
 Mr. Gordon M'Kay, U.S.A., about 1858, made 
 experiments with a little steam-engine (non-condens- 
 ing) with a cylinder only 2 inches in diameter, and 
 found the economy due to steam-jacketing this 
 cylinder was 20 per cent. The steam pressure was 
 115 Ibs. per square inch.J 
 
 Messrs. Bryan Donkin & Co. have, from time to 
 time, carried out a large number of accurate experi- 
 ments to show the economy of using the steam-jacket, 
 and we shall make use of the tables of results they 
 have published very soon. In 1859 and 1870 they 
 carried out experiments on a compound-condensing 
 beam-engine, with cylinders 7J-inch and 14-inch 
 diameter. The economy due to steam-jacketing these 
 
 * Mr. Bryan Donkin in the discussion of Mr. Rich's paper on 
 " Pumping Machinery," read before the Institution of Civil Engineers, 
 1884. 
 
 t Bulletin de la Societe de Mulhonse, No. 133, 1855. 
 
 J Journal of the Franklin Institute, 1859. 
 
MR. B. DONKIN'S TRIALS 157 
 
 two cylinders was found to be 30 to 38 per cent. 
 The feed- water was carefully measured. Expansion, 
 10 to 1 ; and the steam pressure was 45 Ibs. per 
 square inch. In two other experiments the expansion 
 was kept 9 to 1, The steam pressure was 45 Ibs. per 
 square inch. The temperature of the condensing 
 water was also kept the same, and the results were 
 24J Ibs. of steam required per indicated horse-power 
 per hour with steam in the jackets, and 39J Ibs. 
 without steam in the jackets. 
 
 In 1867 the following particulars were obtained 
 during a trial of an eight horse-power nominal portable 
 engine, fitted with a steam-jacket, and provided with 
 the means for turning steam into the jacket or not as 
 required. The weight suspended upon the brake was 
 exactly the same in both experiments. Coal allowed 
 in both experiments was 1 cwt. Actual horse-power 
 developed on the brake = 16 horse-power. Without 
 steam in the jacket 20,665 revolutions were made ; 
 running time, 2 hours 11 minutes. With steam in 
 the jacket 24,920 revolutions were made ; running 
 time 2 hours 20 minutes. The barrel of the cylinder 
 only was steam-jacketed, and not the covers. 
 
 The next table shows the results obtained from 
 careful experiments made in 1868 by Mr. Farey and 
 Mr. B. Donkin, jun., upon a double cylinder-jacketed 
 condensing beam steam-engine of 30 horse-power 
 nominal, constructed by Messrs. B. Donkin & Co., 
 Bermondsey, London. The dimensions of the engine 
 are as follow : 
 
 Ft. In. 
 
 Diameter of high-pressure cylinder, 
 Stroke of high-pressure cylinder, . 3 3 
 
 Diameter of low-pressure cylinder, . 24 
 Stroke of low-pressure cylinder, . 4 6 
 
158 THE EFFICIENCY OF THE STEAM-JACKET 
 
 s . 
 
 1^^ o p -^ 
 
 - 
 
 0,2 
 00 * 
 
 i-H -Q OO 
 
 o <N 
 
 ^ V %? 
 
 r- * T ^JJ ^-* O 
 
 ^ <N OO CO ^1 
 
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 ^ - o 
 
 a 
 
 1^ X 
 1^1 
 
 'S 
 
 
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 ss s i*:^n s ^-s 
 
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 Illlll 
 
 *~Q^%% 
 
MESSRS. DONKINS ENGINE TRIALS 159 
 
 Comparing 3272 Ibs. with 22'51 Ibs. = 10'21 saved 
 per indicated horse-power per hour; and, comparing 
 10-21 Ibs. with 3272 Ibs, = 31 per cent, less feed-water 
 or steam by the use of the jackets and very much 
 more power. 
 
 It is impossible to have more convincing proof of 
 the efficiency of the steam-jacket than that given in 
 the very interesting experiments, carried out in 1869, 
 by Messrs. Donkin and Farey, on a beam engine 
 working as a high-pressure non-condensing engine at 
 Messrs. Donkin's factory, given in Engineering, 16th 
 October 1874, from which we quote the following 
 particulars : These experiments are valuable, seeing 
 that they " show the effect of steam-jacketing on a 
 non-condensing engine working at moderate degrees 
 of expansion, and under conditions which agree with 
 those existing in a large number of engines which are 
 to be found at work at small factories, &c." The 
 cylinder is 7^-inch diameter and 2 ft. 2j-inch stroke, 
 and steam-jacketed. The cylinder and piston were in 
 good working order and free from leakage when the 
 experiments were made. The revolutions made by 
 the engine were registered by a counter, and the 
 indicator diagrams were taken by two indicators driven 
 from the parallel motion direct, and the springs of 
 which had been carefully tested. The expression " full 
 steam " corresponds to a cut-off at about two-thirds of 
 the stroke. 
 
 " The great thing shown by the results, however, is 
 the decided effect exercised by the steam-jacket, even 
 when working with full steam, or with full steam 
 throttled. Under each of these two conditions it 
 effected a saving of nearly 18 per cent., while when 
 working with a cut-off at three-eighths the stroke, the 
 saving rose to nearly 28 per cent. The great increase 
 
160 THE EFFICIENCY OF THE STEAM-JACKET 
 
 f 
 
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 Full Steam. 
 
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 111 
 
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PORTABLE ENGINES 161 
 
 in the mean cylinder pressure, due to the use of the 
 steam-jacket, is also remarkable, and, altogether, the 
 results are of much interest." 
 
 In 1870 Messrs. B. Donkin & Co. made experiments 
 with a single cylinder condensing-engine, cylinder 
 T^-inch. diameter. The economy due to steam- 
 jacketing the cylinder was about 19 per cent. The 
 feed-water was measured. Steam pressure, 45 Ibs. per 
 square inch. Expansion, 2 to 1.* 
 
 In 1871 experiments were carried out on a large 
 single cylinder condensing pumping-engine, when a 
 gain of about 13 per cent, was recorded, due to steam- 
 jac^eting. Steam pressure, 35 Ibs. per square inch. 
 
 The improvements which have been made in 
 portable engines during the last few years, both in 
 design and construction, are well known to everyone ; 
 these improvements have resulted in increased economy 
 of fuel. A large percentage of this increased efficiency 
 is due to the now almost universal practice of steam- 
 jacketing, combined with careful lagging of the 
 cylinders. In the following Table (No. X.) we have 
 reproduced the sizes, particulars, and results of trials 
 of four portable engines tested, among many others, at 
 the Eoyal Agricultural Society's Show at Cardiff, 1872. 
 Two of these engines were fitted with steam-jacketed 
 cylinders, the other two were not jacketed. The 
 difference in the valve gearing is noticed in the table. 
 Particulars of the prize engines are not given in the 
 table, or the results would have been more marked 
 than they already are ; but, knowing that the prize 
 engines had been specially built for racing, and con- 
 tained several details too refined and fragile for every- 
 day use, we prefer to give particulars of four com- 
 
 * Mr. B. Donkin, in the discussion on Mr. Rich's paper on "Pump- 
 ing Machinery," read before the Institute of Civil Engineers, 188i. 
 
 L 
 
162 THE EFFICIENCY OF THE STEAM-JACKET 
 
 mercial engines. It is impossible to state what pro- 
 portion of the decided advantage in economy, which 
 the jacketed engines showed over those unjacketed, 
 was attributable to the steam-jacket ; undoubtedly, 
 the valve gear in some measure contributed to the 
 improvement. 
 
 TABLE X. Four Portable Engines tested at 
 Cardiff, 1872. 
 
 R.A.S.E. Catalogue Number, . 
 
 5024 
 
 4959 
 
 4834 
 
 2950 
 
 Nominal horse-power, 
 
 8 
 
 8 
 
 8 
 
 8 
 
 Maximum steam pressure in 
 
 
 
 
 
 Ibs., 
 
 80 
 
 80 
 
 70 
 
 70 
 
 Heating surface in fire-box in 
 
 
 
 
 
 square feet, .... 
 
 26-3 
 
 35-4 
 
 28-6 
 
 27$ 
 
 Heating surface in tubes in 
 
 
 
 
 
 square feet, .... 
 
 257-2 
 
 133-0 
 
 142-0 
 
 102-4 
 
 Total heating surface in sq. ft., 
 
 283-5 
 
 168-4 
 
 170-6 
 
 129-8 
 
 Diameter of cylinder in inches, 
 
 8* 
 
 8f 
 
 9 
 
 H 
 
 Length of stroke in inches, 
 Cylinder, 
 
 12 
 
 Jacketed. 
 
 12 
 
 Jacketed. 
 
 12 
 
 Unjacketed. 
 
 13 
 Unjacketed. 
 
 Valve gear, 4 
 
 Automatic 
 expansion 
 
 Automatic 
 expansion 
 
 Ordinary 
 slide-valve. 
 
 Ordinary 
 slide-valve. 
 
 Mean boiler pressure in Ibs., . 
 Indicated initial pressure in Ibs., 
 
 80 
 74 
 
 80 
 73 
 
 63 
 41-6 
 
 70 
 47-2 
 
 Indicated mean pressure in Ibs., 
 
 31-23 
 
 33-9 
 
 19-6 
 
 25-8 
 
 Mean revolutions per minute, . 
 
 168 
 
 114-2 
 
 122-6 
 
 116-1 
 
 Mean indicated horse-power at 
 
 
 
 
 
 actual speed, 
 
 18 
 
 13-6 
 
 9-1 
 
 13-8 
 
 Coal used per hour in Ibs. , 
 
 47-2 
 
 38-8 
 
 75-5 
 
 67-2 
 
 Coal used per indicated horse- 
 
 
 
 
 
 power per hour, , 
 
 2-62 
 
 2-85 
 
 8-3 
 
 4-8 
 
 Weight of steam used per indi- 
 
 
 
 
 
 cated horse-power per hour, 
 
 25-9 
 
 29-7 
 
 35-5 
 
 37-5 
 
 Time actually running in hours, 
 
 4-9 
 
 4-20 
 
 1-29 
 
 2-30 
 
 However, no engineer now would attempt to run 
 an unjacketed single cylinder portable engine in a 
 trial against a steam-jacketed one, no matter how 
 many refinements in the valve gearing the unjacketed 
 engine might possess. 
 
 Messrs. B. Donkin & Co., about 1872, found in a 
 compound-condensing engine an economy due to the 
 steam jackets of 25 per cent., the engine indicating 
 140 horse-power with jackets, and 90 horse-power 
 without jackets. Steam pressure, 40 Ibs. per square 
 inch : expansion 4 to 1. 
 
MARINE ENGINES 
 
 163 
 
 Particulars of the following tests made in November, 
 1873, were published in Engineering, 10th April 
 1874. 
 
 Compound-Condensing Marine Engine made by Messrs. 
 Napier &, Sons. 
 
 Steam-Jackets off. 
 
 Steam-Jackets on. 
 
 Pressure in boilers, 58 Ibs. 
 Vacuum, 27-inch. 
 Revolutions per minute, 58. 
 Cut-off high-pressure cylinder, '55. 
 Indicated horse-power, 1031 '65. 
 
 Pressure in boilers, 58 Ibs. 
 Vacuum, 27 -inch. 
 Revolutions per minute, 63. 
 Cut-off high-pressure cylinder, '55. 
 Indicated horse-power, 1184-44. 
 
 The consumption of coal is invariably kept the 
 same during the day of trial ; the weather also is 
 studied, so that, if possible, the ship may be under 
 the same conditions during the trial. The corres- 
 pondent who supplied the information says : " I am 
 aware of other eminent makers who get similar results 
 from steam-jacketing. I hope the above results will 
 convince those of your readers who waver as to the 
 benefits of steam in the jackets." 
 
 The same correspondent, at a later date, says : 
 " In exhaustive trials, conducted under my own care, 
 the saving arising from the use of the steam-jackets 
 amounted to 15 per cent. As to the benefits arising 
 from steam-jackets during a voyage of fifty days, I 
 have seen the gain to be from 25 to 30 knots per 
 day." 
 
 We now give particulars of trials carried out during 
 
 the early part of 1874, by Mr. Hallawer.* These 
 
 experiments were made on a couple of Corliss engines, 
 
 of identical dimensions and design, the only difference 
 
 * Bulletin de la Socitie Industrielle de Mulhouse. 
 
164 THE EFFICIENCY OF THE STEAM-JACKET 
 
 being that the cylinder of one was steam-jacketed and 
 the other was not. 
 
 Diameter of cylinders, 20 '08 inch. Length of 
 stroke, 41*73 inch. Speed, 55 revolutions per minute. 
 Cut-off, one-tenth of the stroke. 
 
 The initial pressure was practically the same in 
 both cylinders ; the cut-off was alike in both engines, 
 yet a far higher mean pressure was obtained in the 
 engine fitted with a steam-jacketed cylinder, as is 
 always the case, owing to the influence of the jacket ; 
 the consumption of water per effective indicated horse- 
 power in the two engines being nearly as 4 to 3. 
 
 
 Engine 
 
 Engine 
 
 Two Separate Corliss Engines. 
 
 with Cylinder 
 Jacketed. 
 
 with Cylinder 
 not Jacketed. 
 
 Absolute initial pressure in cylinder, 
 Absolute ind. horse-power developed, 
 
 74-3 Ibs. 
 101-18 
 
 73 -3 Ibs. 
 69-01 
 
 Effective ind. horse-power developed, 
 
 8315 
 
 56-32 
 
 Water consumed per absolute indi- 
 
 
 
 cated horse-power per hour, 
 
 17 '88 Ibs. 
 
 23-58 Ibs. 
 
 Water consumed per effective indi- 
 
 
 
 cated horse-power per hour, 
 
 21-93 Ibs. 
 
 28-92 Ibs. 
 
 The above results, as will be seen at once, obtained 
 from an entirely different type of engine, afford further 
 evidence of the benefits derived from steam-jacketing. 
 The following Table (No. XL) is extracted from the 
 record of some experiments, made by Mr. Charles 
 Emery, on the engines of the United States Coast 
 Survey steamer " Bache," in the year 1874. The 
 engines were compound, the high-pressure cylinder 
 having a diameter of 15'98 inch., the low-pressure 
 cylinder being 25 inch., and the stroke of both being 
 24 inch. During part of the trials, the large engine 
 was used alone as a simple single-cylinder engine, 
 
MR. EMERY'S TESTS 165 
 
 with and without steam in the jackets. During the 
 remainder of the trial the engines were worked com- 
 pound, the large cylinder with and without jackets; 
 the high-pressure cylinder had no jacket. From an 
 inspection of this Table (No. XL), we see that, under 
 all circumstances, whether the engine was worked 
 simple or compound, a considerable saving was effected 
 by the use of the steam-jacket, when corresponding 
 rates of expansion are compared. For instance, when 
 worked compound, about 3 Ibs. of water was saved 
 per indicated horse-power per hour, being at the rate 
 of about 13 per cent. ; while in the case of the simple 
 engine worked at the higher rates of expansion, as 
 much as 2 2 '5 per cent, was saved. Mr. Emery 
 carried out tests on other marine engines at about the 
 same period, and the results, as given in the published 
 statements, conclusively proved the efficiency of the 
 steam-jacket. "We are indebted to Mr. Holmes's ex- 
 cellent treatise " On the Steam-Engine " for Table XI., 
 and the remarks. 
 
 Messrs. B. Donkin & Co., in 1875, during experi- 
 ments made on a compound-condensing horizontal 
 engine, the high-pressure cylinder 6 inch, diameter, 
 low-pressure cylinder 10 inch, diameter, found that 
 by applying steam to the jackets of both cylinders, 
 the consumption of steam was reduced 32 per cent. 
 Steam pressure, 43 Ibs. per square inch ; expansion, 8 
 to 1. 
 
 From particulars given in Bulletin de la Soctitd de 
 Mulhouse, 1878, of a test carried out on a single 
 cylinder Corliss condensing engine, diameter of cylinder 
 24 inch., the results recorded in favour of steam- 
 jacketing the cylinder ranged from 21 to 30 per cent. ; 
 steam pressure was 60 Ibs. per square inch; expansion, 
 6 to 1. 
 
166 
 
 EFFICIENCY OF THE STEAM-JACKET 
 
 
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CORLISS ENGINE TRIALS 
 
 167 
 
 The following trustworthy and interesting particu- 
 lars of experiments made on a pair of condensing 
 engines, belonging to the world-known establishment 
 of Sir Titus Salt, Bart., Sons & Co., Saltaire, are 
 copied from a reliable source : They are beam, 
 engines of the simple principle, in pairs of two 
 cylinders each. The cylinders are each 50 inch, 
 diameter by 7 feet stroke, with a speed of 30 revolu- 
 tions per minute, making a piston speed of 420 feet 
 per minute. The valves are the Corliss type, with 
 Inglis & Spencer's patented improvements, and made 
 by Messrs. Hick, Hargreaves & Co. The cylinders are 
 steam-jacketed, both around the cylindrical part and at 
 the top and bottom, so that they are entirely sur- 
 rounded with steam at the boiler pressure. 
 
 These experiments were made by Mr. George Salt, 
 to determine the difference in the economy of the 
 engines with and without the jackets : 
 
 
 With the 
 
 Without the 
 
 
 Jackets. 
 
 Jackets. 
 
 Water from the condensation of steam 
 
 
 
 in the jackets for the week, in tons, 
 
 16-85 
 
 ... 
 
 Coal used for the week, in tons, . 
 
 72 
 
 84 
 
 "Water evaporated for the week, in tons, 
 
 510-2 
 
 5847 
 
 The proportion of coal and steam consumed in 
 these cases was 7 without steam in the jackets to 6 
 with steam in the jackets. The weight of water 
 evaporated without steam in the jackets amounts to 
 584*7 tons per week, all of which passes through the 
 cylinders, while with steam in the jacket it was* 501 '2 
 16 '84 = 484'35 tons per week only passed through 
 the cylinders. This leads to the inevitable conclusion 
 that, without steam in the jackets, not only is there 
 
168 THE EFFICIENCY OF THE STEAM-JACKET 
 
 a greater .aggregate consumption of steam in the ratio 
 of" 7 to 6, but also that 5847 - 484'35 = 100'35 
 being a little more than one-sixth of the whole 
 quantity consumed is permanently condensed in the 
 cylinders, and passes out in the state of water, not 
 being re-evaporated. The condensation from the 
 jackets was 16*85 tons, or a little more than one- 
 thirteenth of the whole consumption. 
 
 Messrs. Donkin & Co. proved that it was most 
 essential in a compound engine that the low-pressure 
 cylinder should be thoroughly steam-jacketed, in order 
 to secure the best results, the economy resulting from 
 the application of a steam-jacket to the low-pressure 
 cylinder being under some conditions four times as 
 great as that obtained by jacketing the high-pressure 
 cylinder alone. 
 
 We now give some very interesting particulars of 
 trials, carried out in 1881 on a Corliss engine, having 
 a cylinder 24-inch, diameter and 48-inch, stroke. 
 Ratio of total clearance space to volume swept by the 
 piston, 2 '48 per cent. 
 
 (1) Both sides and ends of the cylinder were steam- 
 jacketed, the jackets receiving steam by a pipe quite 
 detached from the supply-pipe to the valve-chest. 
 The jackets had two steam-traps, one automatic and 
 one requiring to be emptied by hand. 
 
 (2) Arrangements were made by which the piston 
 also could be steam-heated, the condensed steam being 
 discharged through an automatic trap. 
 
 (3) The engine was one of a pair, exactly similar, 
 working on opposite ends of the same shaft, with 
 cranks at right angles to each other. The second 
 engine was not tested, but was kept at work, so 
 that the speed might be maintained constantly without 
 changing the cut-off in the engine under trial. 
 
CORLISS ENGINE TRIALS 
 
 169 
 
 Steam was supplied to the engines by two similar 
 but quite separate boilers, the steam-pipe of each 
 inclining downwards from the engine-room the whole 
 distance to the boiler-house, so as to allow the steam 
 condensed in the pipes to run backwards into the 
 boiler. The following Table (No. XII.) gives the 
 results of experiments on the consumption of steam, 
 based on the direct measurement of the feed-water : 
 
 TABLE XII. 
 
 
 i. 
 
 1 
 
 *l 
 
 *' 
 
 "3.0 3 
 
 
 
 
 
 Ml 
 
 = <*> 5 
 
 li 
 
 ||| 
 
 
 Date. 
 
 i 
 
 || 
 
 111 
 
 
 
 
 REMARKS. 
 
 
 i 1 
 
 8 
 
 |1 S 
 
 i 1 
 
 IP 
 
 
 April 8 
 
 10-71 
 
 66-2 
 
 49-2 
 
 126-6 
 
 24-98 
 
 No steam in jacket 
 
 April 10 
 
 10-66 
 
 67-7 
 
 50-0 
 
 157-1 
 
 19-85 
 
 Steam in jacket only 
 
 April 11 
 
 1076 
 
 66-8 
 
 50-0 
 
 1587 
 
 18-96 
 
 Steam in jacket only 
 
 May 6 
 
 5-68 
 
 67-7 
 
 49-9 
 
 81-9 
 
 27-21 
 
 No steam in jacket 
 
 May 6 
 
 5-07 
 
 68-1 
 
 50-4 
 
 100-3 
 
 18-96 
 
 Steam in jacket only 
 
 May 7 
 
 10-87 
 
 67-9 
 
 50-4 
 
 103-7 
 
 18-51 
 
 Steam in jacket and piston 
 
 Mays 
 
 10-59 
 
 67-2 
 
 51-2 
 
 134-2 
 
 18-53 
 
 Steam in jacket and piston 
 
 April 8, the steam-jacket was not used, the governor 
 was fixed, the speed kept constant ; April 10 and 11, 
 the steam-jacket in use, piston not heated, governor 
 fixed, the speed kept constant ; May 6 (morning), the 
 steam-jacket was not used, the piston not heated ; 
 May 6 (afternoon), the steam-jacket was in use, 
 the piston was not heated ; May 7, the jacket was 
 in use and the piston was heated ; May 8, steam 
 in both jacket and piston, but work reduced to a 
 minimum. 
 
 Working under average conditions : April 8, with- 
 
170 THE EFFICIENCY OF THE STEAM-JACKET 
 
 out the jacket, the engine developed 127'6 horse- 
 power, with a consumption of 247 Ibs. of steam per 
 indicated horse-power per hour. Under exactly 
 similar conditions, except the jacket in use, on April 
 10, the work rose to 157*13 horse-power, and the con- 
 sumption fell to 19*85 Ibs. of steam per indicated 
 horse-power per hour, showing 19*6 per cent, gained 
 by the jackets. 
 
 This was in spite of a somewhat defective action 
 of the steam-traps, which, being put right on the 
 next day (April 11), the consumption fell to 18*96 
 per indicated horse-power per hour, a gain of 23*5 per 
 cent. Comparing the mean of the two days' work in 
 each case, we find that the same engine did 237 per 
 cent, more work with the jackets than without them, 
 with a saving of steam per indicated horse-power per 
 hour of 21*6 per cent. Comparing the working of the 
 engine on the morning and afternoon of 6th May, 
 when the power was smaller, the results are even 
 more striking. 
 
 The power is raised from 81 indicated horse-power 
 to 100*3 indicated horse-power, or 23*7 per cent., 
 while the water used per indicated horse-power per 
 hour has fallen from 27*2 to 18*96 Ibs., or 30'2 per 
 cent. No economy appears to have resulted from 
 heating the piston. The above trials were conducted 
 by MM. Walker Meunier (chief engineer of the 
 Association Absaciene des Proprietaries d'Appareils 
 a Vapeur) and Gr. Keller, of the same society. The 
 engine tested was a Corliss engine, made by Messrs. 
 Berger Andre & Co., of Thaun. 
 
 We have pleasure in giving the results in favour 
 of steam-jacketing, extracted from a most valuable 
 paper, "On the Independent Testing of Steam-Engines 
 and the Measurements of Heat Used," by Mr. M. J. G. 
 
MR. HAIR'S TESTS 
 
 in 
 
 Mair, M.LC.E.^ By this system of testing viz., the 
 practical measurement of heat units; among many 
 other things which can be settled is the relative values 
 of compound or simple engines, and the saving by the 
 use of steam-jackets absolutely proved. 
 
 Out of ten trials made on various types of engines, 
 we give a few particulars of five trials : 
 
 TABLE XIII. 
 
 
 B. 
 
 C. 
 
 D. 
 
 E. 
 
 F. 
 
 Date of trial, .... 
 
 Aug. 1881 
 
 Aug. 1881 
 
 Dec. 1881 
 
 Dec. 1881 
 
 Dec. 1881 
 
 Type of engine, 
 
 Com. Woolf Beam 
 
 Compc 
 
 und Wool 
 
 Beam 
 
 Time running in hours and 
 
 
 
 
 
 
 minutes, .... 
 
 6-0 
 
 10-0 
 
 10-0 
 
 11-0 
 
 10-0 
 
 Total number of revolutions 
 
 
 
 
 
 
 from counters, 
 
 6,421 
 
 11,772 
 
 20,238 
 
 22,584 
 
 20,710 
 
 Revolutions per minute, . 
 
 17-84 
 
 19-62 
 
 33-73 
 
 34-22 
 
 34-52 
 
 Indicated horse-power, 
 Total horse-power, . 
 
 75-9 
 87-36 
 
 75-2 
 85-09 
 
 267-86 
 284-25 
 
 267-K4 
 282-55 
 
 267-91 
 288-69 
 
 Water drained in jackets in 
 
 
 
 
 
 
 pounds, .... 
 
 Not in use 
 
 1345 
 
 3502 
 
 4284 
 
 Not in use 
 
 Total number of expansions, . 
 
 9-30 
 
 15-76 
 
 9-64 
 
 9-56 
 
 7-77 
 
 Absolute boiler pressure in 
 
 
 
 
 
 
 pounds per square inch, 
 
 58 
 
 62 
 
 84-8 
 
 88-14 
 
 88-95 
 
 Percentage of supply from boiler 
 
 
 
 
 
 
 passed through the jackets, . 
 Percentage of water present in 
 
 Not in use 
 
 9-9 
 
 7-1 
 
 8-3 
 
 Not in use 
 
 the cylinder at cut-off, . 
 
 51-1 
 
 40-8 
 
 37-6 
 
 37-7 
 
 34-0 
 
 Percentage of water present in 
 
 
 
 
 
 
 the cylinder at end of high- 
 
 
 
 
 
 
 pressure stroke, . 
 
 35-1 
 
 18-1 
 
 24-3 
 
 21-5 
 
 28-0 
 
 Percentage of water present in 
 
 
 
 
 
 
 the cylinder at end of low- 
 
 
 
 
 
 
 pressure stroke, 
 
 38-8 
 
 8-7 
 
 17-5 
 
 14-3 
 
 35-2 
 
 Percenta ge of total heat through 
 
 
 
 
 
 
 engine lost by the cooling 
 
 
 
 
 
 
 action of the condenser, 
 
 24-4 
 
 3-1 
 
 11-3 
 
 9-4 
 
 22-5 
 
 Thermal units per indicated 
 
 
 
 
 
 
 horse-power per minute, 
 
 519-5 
 
 338-8 
 
 348-1 
 
 341-8 
 
 378-1 
 
 Thermal units per total horse- 
 
 
 
 
 
 
 power per minute, 
 
 451-4 
 
 299-3 
 
 328-1 
 
 324-2 
 
 350-9 
 
 Pounds of dry saturated steam 
 
 
 
 
 
 
 per ind. horse-power per hour, 
 
 26-62 
 
 17-34 
 
 17-73 
 
 17-39 
 
 19-24 
 
 Maximum th eoretical efficiency, 
 
 0-254 
 
 0-276 
 
 0-340 
 
 0-339 
 
 0-341 
 
 Actual efficiency, 
 
 0-082 
 
 0-126 
 
 0-122 
 
 0-125 
 
 0-113 
 
 Pounds of coal used per indi- 
 
 
 
 
 
 
 cated horse-power per hour, 
 
 2-66 
 
 1-76 
 
 1-86 
 
 1-83 
 
 2-02 
 
 Radiation per cent., . 
 
 1-6 
 
 2-7 
 
 1-2 
 
 1-3 
 
 1-2 
 
 Trials B and C. A Woolf beam rotative engine, 
 working a deep-well pump direct from the beam. It 
 
 * See Minutes of Proceedings of the Institution of Civil Engineers, 
 Vol. LXX. p. 313, &c. 
 
172 THE EFFICIENCY OF THE STEAM-JACKET 
 
 was made by Messrs. Simpson & Co., and had been at 
 work six mouths before the trials were made. The 
 cylinders were 34 inch, in diameter by 5 feet 6 
 inch, stroke, and 22 inch, in diameter by 3 feet 7 
 inch, stroke, with their covers and bases jacketed 
 with boiler steam. Two trials were made with this 
 engine, one trial with, and the other without, steam in 
 the jackets : the results of both trials are given in 
 Table XIII. 
 
 Trials D, J, F. A Woolf beam engine driving a 
 flour mill. It was made by Messrs. Simpson & Co. 
 The cylinders 38 inch, in diameter by 5 feet 6 inch, 
 length of stroke, and 24^ inch, in diameter by 3 feet 
 5 inch, length of stroke, were steam-jacketed on the 
 barrels only. Three trials were made with this 
 engine, two with, and one without, the jackets. The 
 results of these trials are given in Table XIII. 
 
 Mr. Mair says : " Trials B and C are interesting, as 
 showing the great loss that existed when the steam- 
 main was not thoroughly drained and the jackets 
 shut off, 519'5 thermal units being used in that case, 
 against 338*8 thermal units when the main was better 
 drained and the jackets were on. The water present 
 at the cut-off was oil per cent., the loss by the cool- 
 ing action of the condenser being reduced in the latter 
 case when the jackets were on from 244 per cent, to 
 31 per cent. 
 
 " In the next trials, D, E, and F, it will be noticed 
 that the best results, 348 '8 thermal units, were 
 obtained when 8*3 per cent, of steam passed through 
 the jackets, against 3481 when only 71 per cent, 
 passed, the water present at the toe of the low-pressure 
 diagram being 14'3 per cent, against 17'5 per cent., 
 and the loss due to the cooling action of the condenser 
 9'4 per cent, instead of 11 '3 per cent. When the 
 
LARGE PUMPING ENGINES 
 
 173 
 
 jackets were shut off 3781 thermal units were used, 
 or a loss of 10^ per cent., the loss due to the cooling 
 action of the condenser being 22'5 per cent. Had 
 the cylinders been better jacketed that is, the covers 
 and bottoms, in addition to barrels, the loss through 
 shutting off the jackets would undoubtedly have been 
 greater in proportion." 
 
 It will be seen from these results that great advan- 
 tage was in each case gained by the jackets being at 
 work, and they were productive of economy. On the 
 
 Fig. 62. Scale fa 
 
 Chatham Waterworks. Steam in Jackets. 
 
 Indicated horse-power, high-pressure 35 '4 
 
 Indicated horse-power, low-pressure 39 '8 
 
 Total indicated horse-power 7 5 '2 
 
 Consumption of steam per indicated horse-power 17 "34 Ibs. 
 
 B and C trials, the gain was 34| per cent, by using 
 jackets and draining the steam-main, and on the D, E, 
 and F trials it was seen how the better discharge 
 from the jacket increased the efficiency, and how 10 J 
 per cent, was lost by their being shut off. 
 
 In the discussion which followed the reading of Mr. 
 
174 THE EFFICIENCY OF THE STEAM-JACKET 
 
 Rich's very interesting paper on " Pumping Engines," 
 before the Institution of Civil Engineers, 1884, Mr. 
 Mair furnished two sets of diagrams taken from the 
 same engines at the Chatham Waterworks, illustrating 
 the economy of the steam-jacket. Fig. 62 shows 
 diagrams from the engine with steam in the jackets, 
 when the total indicated power developed by the 
 engine was 75*2, and the consumption of steam per 
 indicated horse-power per hour was 17'34 Ibs. Fig. 
 63 shows diagrams from the same engine without 
 
 ' 1 
 
 Fig. 63. 
 
 Chatham Waterworks. No Steam in Jackets. 
 
 Indicated horse-power, high-pressure 44 '6 
 
 Indicated horse-power, low-pressure 31*3 
 
 Total indicated horse-power 75 '9 
 
 Consumption of steam per indicated horse-power, 26 '62 Ibs. 
 
 steam in the jackets, when a much later cut-off was 
 required to develop a total of 75 '9 indicated horse- 
 power, and the consumption of steam rose to 2 6 '6 2 
 Ibs. per indicated horse-power per hour. The speed 
 and the boiler pressure were kept exactly the same in 
 both cases. 
 
 Mr. E. A. Cowper, M.I.C.E., in his lecture " On the 
 
MR. RENNIE'S TRIALS 175 
 
 S team-Engine," read before the Institution of Civil 
 Engineers in 1884, refers to trials carried out by Mr. 
 Eennie, extending over two periods of four weeks each, 
 with and without steam in the jackets, of a 40 horse- 
 power stationary engine, when the coal consumption 
 showed a gain of 31 per cent, in favour of steam- 
 jacketing. 
 
 We have now reached the conclusion of the results 
 of engine tests carried out to ascertain the value of 
 steam-jacketing, collected and published by the author 
 of this work in 1889.* 
 
 Soon after their appearance, the first of the two 
 excellent reports of the Eesearch Committee on " The 
 Value of the Steam-Jacket," was published followed 
 three years later by the second report. "We are able 
 in the present chapter, by the kind permission of the 
 Council of the Institution of Mechanical Engineers, to 
 add a few abbreviated tables of results, carried out on 
 various classes of engines from these reports. We 
 have supplemented the whole by reproducing Mr. 
 Donkin's valuable and exhaustive tests on the experi- 
 mental vertical engine at Bermondsey. 
 
 It will be seen from the tables recorded in this 
 chapter, that, whether the engines have been simple 
 or compound, condensing or non-condensing, of large 
 or small proportions, an economy has always resulted 
 from, thorough steam-jacketing. But " the smaller the 
 cylinder, the greater is the percentage of gain from the 
 use of the jacket." t It may be of service to point 
 out here that, in testing the same engine with and 
 without steam in the jackets, the results from the 
 jacketed engine would show a greater gain than those 
 recorded, because the empty steam-jackets round the 
 
 * The Mechanical World. 
 
 t Second Report on "The Value of the Steam- Jacket," p. 420. 
 
176 THE EFFICIENCY OF THE STEAM-JACKET 
 
 cylinder will cause the so-called non-jacketed engine 
 to give a much better result than another engine 
 would, without this empty ring. It is a well-known 
 fact that the annular space acts as an excellent non- 
 conductor to the working steam inside the cylinder 
 barrel. It would be useful, therefore, to have some tests 
 carried out on two engines of precisely the same design, 
 and working under exactly the same conditions, one 
 cylinder steam-jacketed and lagged, the other cylinder 
 not steam-jacketed, and lagged in the same manner. 
 
 On p. 164 we have given the results of two 
 trials made on a couple of Corliss engines of identical 
 dimensions and design, the only difference being that 
 the cylinder of one was steam-jacketed and the other 
 was not. 
 
 The results of the above experiments are very 
 interesting, because they show the exact value of 
 steam-jacketing without the non-jacketed cylinder 
 having the advantage of a liner with an air-jacket. 
 
 Sir Frederick Bramwell, Bart., " mentioned a practi- 
 cal test, wholly unpremeditated and unconcerted, of 
 the value of steam-jackets, which had occurred in his 
 own experience. Some thirty years ago he had 
 designed a tandem compound engine for some saw- 
 mills, with steam-jacketed cylinders high enough up 
 for the jacket water to be returned by gravitation to 
 the boiler. After the engine had worked ten years, 
 it happened one day that it could not be made to go. 
 Having been sent for, he found on examination that 
 everything appeared to be right ; and he had no notion 
 what was the matter, until, by good luck, he put his 
 hand upon the return pipe from the jackets and felt 
 that it was quite cold. On being taken off, it was 
 found that, after all those years, the drain-pipe had 
 become choked up with a deposit of lime. It was 
 
M. DELAFONUS TESTS 177 
 
 cleaned and put on again, and then the engine worked 
 as well as ever." * The above fact speaks for itself, 
 and we could furnish many other similar experiences, 
 but we must now give the tables of results which prove 
 to demonstration the efficiency of steam-jacketing. 
 
 In Table XIV. we give the results of four out 
 of twenty-four experiments carried out by M. Dela- 
 fond at the Creusot Works, France. The experiments 
 were made on a single cylinder non-condensing Corliss 
 engine ; cylinder, 21 '6 5 inch, diameter, 43 '31 inch, 
 stroke : the body only was jacketed. The jackets 
 were supplied with steam by a small pipe from the 
 main steam-pipe, and were automatically drained. 
 
 In the next table six out of forty-six experiments 
 are given. These figures show the results obtained 
 by M. Delafond from the same engine with the con- 
 denser at work. It is very interesting to compare 
 the results obtained from the same engine working 
 first as non-condensing and afterwards with the con- 
 denser at work. 
 
 We now record two experiments made on a com- 
 pound surface-condensing three cylinder vertical engine. 
 Cylinders 19-, 25- and 25-inch, diameter, 24-inch, 
 stroke : only the bodies of the cylinders were jacketed. 
 Experiments made at the London Hydraulic Power 
 Pumping Station in 1887, by Professor Kennedy and 
 Mr B. Donkin. Steam supply to jacket by small pipe. 
 Steam from small cylinder expanded into two large 
 cylinders. Table XVI. 
 
 The experimental engine at University College, 
 London, with which the trials recorded in Table 
 XVII. was carried out, is of the compound tandem 
 type, manufactured by Messrs. Bryan Donkin & Co. 
 
 * Second Report of the Research Committee on "The Value of the 
 Steam- Jacket," 1892. 
 
 M 
 
178 THE EFFICIENCY OF THE STEAM-JACKET 
 
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 Number of expansions, 
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 Feed-water, Ibs. per inc 
 Feed-water, percentage 
 
 Duration of experiment 
 Boiler pressure, Ibs. 
 atmosphere, 
 Number of expansions, 
 Indicated horse-power, 
 Feed-water, Ibs. per ind 
 Feed-water, percentage 
 
CORLISS ENGINES 
 
 179 
 
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180 THE EFFICIENCY OF THE STEAM-JACKET 
 
 Cylinders 6-inch, and 10-inch, diameter, 12-inch, 
 stroke : only the bodies of the cylinders were jacketed. 
 Experiments made at Bermondsey from 1875 to 1881 
 
 TABLE XVI. 
 
 Compound Surface Condensing 
 Engine. 
 
 Without Steam 
 ia Jackets. 
 
 With Steam 
 in Jackets. 
 
 Duration of experiment in hours, 
 
 9 
 
 9 
 
 Boiler pressure Ibs. per square 
 
 
 
 inch above atmosphere, . 
 
 80 
 
 80 
 
 Number of expansions, 
 Indicated horse-power, 
 
 7 
 157 
 
 7 
 . 168 
 
 Feed-water Ibs. per indicated 
 
 
 
 horse-power per hour, 
 
 23-93 
 
 20-25 
 
 Feed-water percentage less with 
 
 
 
 jackets, ..... 
 
 
 15'4 
 
 by Messrs. Farey, B. Donkin, jun., and Salter. The 
 whole steam-supply to the cylinders passed through 
 the jackets when in use, which were drained by traps. 
 When not in use the jackets were open to the air. 
 
 It is impossible to over-estimate the value of the 
 test carried on in the compound engine, the results 
 of which are given in Table XVII. 
 
 There are many engineers, while admitting the 
 utility of the steam-jacket when applied to the simple 
 engine, yet they question the economy of applying a 
 jacket to both the cylinders of a compound engine. 
 They agree that one of the cylinders should be 
 jacketed, but they are very much divided when it 
 comes to the question as to which of the two cylinders 
 should be steam-jacketed. Tor instance, one writer 
 says : There is reason to believe that the loss by 
 condensation which takes place in the jackets of low- 
 pressure cylinders is so great as to justify the use of 
 unjacketed low-pressure cylinders." * Mr. Stapfer, in 
 * The Engineer, 3rd December 1873. 
 
MR. RICH'S REMARKS 
 
 181 
 
 1874, said : " In compound engines, only the small 
 cylinder and the reservoir (receiver) should be jacketed." 
 
 TABLE XVII. 
 
 Average Results from three experiments with si 
 pressure jacket alone, and four experiments 
 either jacket. 
 
 High-pressure jacket alone, with or without steam. 
 
 earn in th 
 
 without s1 
 
 Without. 
 
 e high- 
 earn in 
 
 With. 
 
 Indicated horse-power, ..... 
 Thermal units rejected per indicated horse-power 
 per minute, ....... 
 Thermal units, percentage less with steam in 
 
 875 
 563 
 
 7'86 
 419 
 25-5 
 
 
 
 Average Results from seven experiments with stei 
 jacket alone, and four experiments withou 
 jacket. 
 
 Low-pressure jacket alone, with or without steam. 
 
 im in low-p 
 t steam in 
 
 Without. 
 
 ressure 
 either 
 
 With. 
 
 Indicated horse-power, ..... 
 Thermal units rejected per indicated horse-power 
 per minute, . . . . . . , 
 Thermal units, less with steam in low-pressure 
 cylinder alone, ...... 
 
 875 
 563 
 
 9-89 
 400 
 29-0 
 
 
 
 Average Results from eight experiments with stea 
 and four experiments without steam in eithei 
 
 Both jackets, with or without steam. 
 
 m in both J 
 ^ jacket. 
 
 Without. 
 
 ackets, 
 With. 
 
 Indicated horse-power, ..... 
 Thermal units rejected per indicated horse-power 
 per minute, 
 Thermal units, percentage less with steam in 
 both jackets, ....... 
 
 875 
 563 
 
 9-4 
 372 
 33-9 
 
 Mr. Eich says : " Their firm were so convinced of 
 the great importance of having steam-jackets in all 
 cases on both cylinders, that they have since made no 
 
132 THE EFFICIENCY OF THE STEAM-JACKET 
 
 large compound engines without them."^ Mr. Bryan 
 Donkin comes to our aid, and proves to demonstration 
 by these useful tests that, if the utmost economy is to 
 be realised by compounding, both the high and low- 
 pressure cylinders should be steam-jacketed. It will, 
 however, be seen from the figures that the jacket on 
 the low-pressure cylinder was more productive of good 
 than the jacket on the high-pressure cylinder. Yet 
 it is valuable to have both cylinders thoroughly steam- 
 jacketed and well drained. 
 
 The next table gives particulars of tests carried out 
 by Professor A. B. W. Kennedy on the same engine 
 with which the trials recorded in Table XVII. 
 were made. The cylinders are 6-inch, and 10-inch, 
 in diameter. An expansion valve of the Meyer type 
 is fitted to the high-pressure cylinder, by means of 
 which the cut-off can be made to take place at any 
 point in the stroke. Both cylinders are jacketed, and 
 during the trials the steam circulated through both 
 jackets before entering the high-pressure valve-chest. 
 
 TABLE XVIII. 
 
 Compound Condensing 
 
 Jackets 
 not in 
 
 Both 
 Jackets 
 
 Jackets 
 not in 
 
 Both 
 Jackets 
 
 Jackets 
 not in 
 
 Both 
 Jackets 
 
 Engines. 
 
 Use. 
 
 in Use. 
 
 Use. 
 
 in Use. 
 
 Use. 
 
 in Use. 
 
 Duration of experiment 
 
 
 
 
 
 
 
 in hours, 
 
 2 
 
 2-2 
 
 2-0 
 
 175 
 
 1-8 
 
 2-0 
 
 Absolute boiler pressure, 
 
 39-4 
 
 48-3 
 
 80 
 
 82-1 
 
 94-6 
 
 94-0 
 
 Ratio of expansion, 
 
 3-23 
 
 3-56 
 
 8'95 
 
 11-10 
 
 8-25 
 
 8-43 
 
 Indicated horse-power, 
 
 7'25 
 
 974 
 
 6'90 
 
 8-45 
 
 10-37 
 
 13-03 
 
 Feed-water per ind. 
 
 
 
 
 
 
 
 horse-power per hour, 
 
 41-60 
 
 3175 
 
 42-98 
 
 27-86 
 
 38-0 
 
 23-48 
 
 Feed-water, percentage 
 
 
 
 
 
 
 
 less with steam -in 
 
 
 
 
 
 
 
 jackets, . 
 
 ... 
 
 237 
 
 ... 
 
 35-2 
 
 ... 
 
 38-2 
 
 * "The Comparative Merits of Engines for Pumping : " a paper read 
 before the Institution of Civil Engineers by Mr. Rich, 1884. 
 
TRIPLE-EXPANSION CONDENSING ENGINE 183 
 
 Record of two experiments on the same engine, 
 with and without steam in the jackets, are given in 
 Table XIX. Triple-expansion condensing vertical in- 
 verted engine, on three uncoupled cranks, with cylin- 
 ders provided with Meyer expansion gear. Cylinders 
 5-, 8- and 12-inch, diameter; 10-, 10- and 15-inch, 
 stroke. All the bodies, ends, and valve-chests of the 
 three cylinders were jacketed, as also were both re- 
 
 TABLE XIX. 
 
 Triple Expansion Engine. 
 
 Without Steam 
 in Jackets. 
 
 With Steam 
 in Jackets. 
 
 Duration of experiment in hours, 
 
 4-0 
 
 4-1 
 
 Boiler pressure, Ibs. per square 
 
 
 
 inch above atmosphere, . 
 
 188 
 
 192 
 
 Number of expansions, 
 
 15 
 
 26'5 
 
 Indicated horse-power, 
 
 73-9 
 
 721 
 
 Feed-water per indicated horse 
 
 
 
 power per hour in Ibs. , 
 
 16-42 
 
 13-56 
 
 Feed-water, percentage less with 
 
 
 
 steam in jackets, 
 
 ... 
 
 17-4 
 
 ceivers, and part of the steam-pipe, steam being ad- 
 mitted to the last three jackets throughout both of 
 the experiments.^ Steam was supplied to each of the 
 fifteen jackets by a separate pipe, and all the jacket 
 water was drained through the first receiver into the 
 boiler. In the high-pressure cylinder 647 per cent, 
 of the internal surface is jacketed, in the intermediate 
 cylinder 671 per cent., and in the low-pressure cylinder 
 75*2 per cent. Three independent brakes were used 
 to absorb the power. 
 
 Experiment on a triple-expansion engine at the 
 
 * Experiments made at Owens College, Manchester, in January and 
 April, 1889, by Professor Osborne Reynolds (Institution of Civil 
 Engineers, vol. xcix., 1889). 
 
184 THE EFFICIENCY OF THE STEAM-JACKET 
 
 Waltham Abbey Pumping Station of the East London 
 Waterworks, by Mr. Henry Davey and Mr. William 
 B. Bryan. The diameter of the cylinders are 18- 
 inch. 305-inch., and 51-inch., respectively. The 
 stroke of each of the three cylinders is 36-inch. 
 Each piston cross-head is connected to its crank by a 
 single connecting rod, and to a pump-plunger by a 
 pair of pump-rods. There are thus three steam- 
 cylinders, three pump-plungers, three connecting-rods, 
 and three pairs of pump-rods. Each of the three 
 cylinders is provided with an ordinary slide-valve, 
 actuated by a separate eccentric on the crank-shaft. 
 The slide-valve on the high -pressure cylinder is actuated 
 direct by its eccentric, and is provided with a Meyer 
 expansion valve, by means of which the speed of the 
 engine was regulated during the experiment. The 
 slide-valves on the intermediate and low-pressure 
 cylinders are actuated through variable expansion 
 links, but the positions of these remained unchanged 
 throughout the experiment. 
 
 The bodies and both ends of all three cylinders are 
 steam-jacketed, the cylinders forming liners in the 
 body jackets. Steam is supplied to these jackets ' 
 through a pipe connected to the main steam-pipe on 
 the boiler side of the stop-valve. The steam to the 
 jackets enters at the top on one side, and at the 
 bottom on the opposite side ; and, in ordinary working, 
 the high-pressure jackets discharge directly into the 
 boiler, while the intermediate and low-pressure jackets 
 discharge through steam-traps into the hot-well. The 
 jackets of the high-pressure cylinder receive steam at 
 full boiler pressure ; and, by means of reducing valves, 
 the pressures in the jackets of the intermediate and 
 low-pressure cylinders are maintained a little higher 
 than the pressures in their respective steam-chests. 
 
MR. DONKIN'S TESTS 
 
 185 
 
 Each cylinder is therefore jacketed with steam a little 
 above its own initial pressure. See Table XX. 
 
 TABLE XX. 
 
 Triple Expansion Engine. 
 
 Without Steam 
 in Jackets. 
 
 With Steam 
 in Jackets. 
 
 Duration of experiment in hours, 
 
 8 
 
 8 
 
 Boiler pressure, Ibs. per square 
 
 
 
 inch above atmosphere, . 
 Number of expansions, 
 
 130 
 
 22 
 
 130 
 30 
 
 Indicated horse-power, 
 
 140 
 
 138 
 
 Feed-water per indicated horse- 
 
 
 
 power per hour, . . Ibs. 
 
 17-22 
 
 15-45 
 
 Feed-water, percentage less with 
 
 
 
 jackets, ..... 
 
 
 10-3 
 
 Coal per indicated horse-power per 
 
 
 
 hour in Ibs., .... 
 
 2-09 
 
 1-79 
 
 The following steam-jacket experiments were made 
 on a single cylinder vertical experimental engine at 
 Bermondsey, by Mr. Bryan Donkin, jun. The cylin- 
 der is 6-inch, diameter, and the stroke 8-inch. 
 The slide-valve is provided with a Meyer variable 
 expansion valve. The body and both ends of the 
 cylinder are jacketed, as is also the valve-chest cover ; 
 and steam is supplied to each of the four jackets 
 direct from the boiler by a separate pipe. By a 
 special arrangement, the water from the cylinder body- 
 jacket was divided into two portions, and the weights 
 of these are given separately. The first portion con- 
 sists of the steam condensed on the inner vertical 
 surface of the jacket, and is due to the heat passing 
 through the walls into the cylinder, almost all of 
 which is usefully employed in keeping the tempera- 
 ture of the cylinder nearly equal to that of the steam 
 in the jacket. The other portion consists of the 
 steam condensed on the outer vertical surface of the 
 
186 THE EFFICIENCY OF THE STEAM-JACKET 
 
 jacket, and is due to the heat uselessly radiated out- 
 wards owing to imperfect external covering. This 
 loss should, of course, be reduced to a minimum, and 
 in these experiments a layer of good non-conducting 
 material was placed round the cylinder for this pur- 
 pose. Observations of the temperatures of the cylinder 
 walls were made throughout the trials. These tempera- 
 tures were taken by small thermometers inserted in 
 J-inch holes, drilled into the metal walls and filled with 
 mercury. It will be seen from Tables XXI. to XXV., 
 that the temperature of the cylinder walls was much 
 higher with steam in the jackets than without. 
 
 Experiments were made not only with and without 
 steam in the jackets, but also with all the jackets 
 filled with water, which was allowed to assume a 
 normal temperature before commencing the trial ; a 
 trial was also made with a vacuum in the body jacket. 
 When no steam is admitted into the jackets the air 
 in them gets gradually hotter, being heated by the 
 cylinder walls, until it reaches a normal temperature. 
 The same thing occurs when cold water is admitted 
 into the jackets ; it gradually becomes hotter, and 
 then remains at a constant temperature. 
 
 Experiments were made at two different speeds 
 about 218 and 115 revolutions per minute. In order 
 to shorten the duration of the trials, the engine was 
 fitted with a surface-condenser to measure the feed- 
 water, and it was found that trials lasting for half an 
 hour agreed satisfactorily with those of three hours' 
 duration. 
 
 The steam pressure and cut-off were kept constant 
 throughout the whole of the experiments, with the 
 exception of No. 24, in which the cut-off was varied. 
 A brake was used to absorb the power. 
 
 Five experiments were made on this engine, four 
 
MR. DONKIN'S TESTS 187 
 
 condensing and one non- condensing. Experiment No. 
 21 consisted of four trials at about full speed, with 
 steam in all the jackets ; without steam in any of the 
 jackets ; with water in all the jackets ; and with a 
 vacuum in the body jacket. Experiment No. 22 con- 
 sisted of two trials at about half speed, with and 
 without steam in all the jackets. Experiment No. 23 
 consisted of two non-condensing trials at about full 
 speed, with and without steam in all the jackets. 
 Experiment No. 24 consisted of twelve trials, all at 
 full speed, made in pairs, one unjacketed and one 
 jacketed, with six different degrees of expansion, in 
 order to determine how the changes in the ratio of 
 expansion would effect the value of the steam-jackets. 
 In Experiment No. 25 steam was admitted to the 
 body jacket and shut off again during the experiment, 
 without stopping the engine, in order to ascertain the 
 effect of this upon the speed of the engine, the load 
 on the brake being kept constant. 
 
 In all the experiments, the feed-water always in- 
 cluded the whole of the jacket water. 
 
 Experiment No. 21. Four trials with different 
 media in jackets. The details of this experiment are 
 given in Table XXI. These four trials were all made 
 at a mean speed of about 218 revolutions per minute, 
 condensing, and at a cut-off of three-sixteenths. The 
 first trial was made without steam in any of the jackets, 
 that is, with hot air in all the jackets, and lasted for 
 34 minutes. The consumption of feed-water was at the 
 rate of 41 '2 3 Ibs. per indicated horse-power per hour. 
 
 The second trial was made with steam in all the 
 jackets, and lasted for 52 minutes. The consumption 
 of feed-water, including jacket-water, was at the 
 rate of 28*39 Ibs. per indicated horse-power per hour, 
 showing a saving in feed-water of 41*23 28*39 = 
 
188 THE EFFICIENCY OF THE STEAM-JACKET 
 
 12 '84 Ibs. per indicated horse-power per hour, or a 
 decrease in consumption of 31*1 per cent., due to the 
 action of steam as compared with hot air in the four 
 jackets. The mean temperature of the internal part 
 of the cylinder walls was 28 higher with steam in 
 the jackets than with hot air. The condensed water 
 from the various jackets was as follows : 
 
 Condensed water. 
 0-69 Ib. per I.H.P. per hour. 
 0-68 Ib. 
 0-15 Ib. 
 0-41 Ib. 
 
 Jacket. 
 
 Body jacket, inner wall, 
 ,, ,, outer wall, 
 Top-end jacket, 
 Bottom-end jacket, . 
 Valve-chest jacket, . 
 
 Total jacket- water, . 
 
 The total quantity of steam condensed in the 
 jackets was, therefore, 2'11 Ibs. per indicated horse- 
 power per hour, which is equivalent to 7*44 per cent, 
 of the total feed-water. Thus, for every pound of 
 steam condensed in the jackets, there was a net sav- 
 ing in feed-water consumption of 6'1 Ibs. The 
 following table shows the effect of the different jackets 
 on the feed-water consumption, as determined by 
 another experiment : 
 
 Arrangement of Jacketing. 
 
 Feed-water, including Jacket-water. 
 
 Consumption 
 per indicated 
 Horse-power 
 per hour. 
 
 Saving due to Steam-jackets. 
 
 Per indicated 
 Horse-power 
 per hour. 
 
 Percentage 
 of 41-2. 
 
 Without steam in any of 
 the jackets, . 
 With steam in two end 
 jackets only, 
 With steam in body jacket 
 only, .... 
 With steam in all four 
 jackets, 
 
 41 '2 Ibs. 
 37-0 Ibs. 
 30-1 Ibs. 
 28'4 Ibs. 
 
 4'2 Ibs. 
 11-1 Ibs. 
 12-8 Ibs. 
 
 10'2 per cent. 
 26-9 
 31-1 
 
MR. DONKIN'S TESTS 189 
 
 The third trial was made with hot water in all the 
 jackets, and lasted for 221 minutes, the water in the 
 jackets being allowed to assume a normal temperature 
 before the observations were commenced. The con- 
 sumption of feed-water was at the rate of 46*27 Ibs. 
 per indicated horse-power per hour, showing a differ- 
 ence in feed-water consumption of 46*27 41/23 = 5'04 
 Ibs. per indicated horse-power per hour, or an increase 
 of 12*2 per cent., due to the presence of hot water in 
 the jackets, as compared with hot air. In the fourth 
 trial, which lasted for 26 minutes, a vacuum of 12*85 
 Ibs. per square inch below the atmosphere was main- 
 tained in the body jacket by putting it in direct com- 
 munication with the condenser, the other three jackets 
 being open to the air. The consumption of feed-water 
 was at the rate of 38*01 Ibs. per indicated horse-power 
 per hour, showing a saving in feed- water of 41*23 
 38*01 = 3*22 Ibs. per indicated horse-power per hour, 
 or a decrease of 7*8 per cent, due to maintaining a 
 vacuum in the body jacket, as compared with hot air 
 in all the jackets. This trial with a vacuum in the 
 body jacket, and was made with the intention of lower- 
 ing the temperature of the cylinder walls, but a little 
 reflection showed that there was no medium to convey 
 the heat from the hot metal walls to the cooler condenser. 
 
 The walls were found to remain at a temperature 
 of 264 F., without parting with their heat, although 
 exposed to the much lower condenser temperature 
 of 130 F. 
 
 This has since been confirmed by further experi- 
 ments, and shows a practical result which is not un- 
 important. The cylinder walls were rather hotter 
 with a vacuum in the body jacket than with hot air 
 in all the jackets, and external radiation was probably 
 diminished. 
 
190 THE EFFICIENCY OF THE STEAM-JACKET 
 
 Experiment No. 22. Two trials at half -speed with 
 and without steam in jackets. The details of this 
 experiment are given in Table XXII. 
 
 The trials were made at a mean speed of about 
 116 revolutions per minute, condensing, and at a cut- 
 off of three-sixteenths. 
 
 With the exception of the speed, which was a little 
 more than half, all the conditions were the same as 
 those for the first two trials of Experiment No. 21. 
 
 The trial without steam in any of the jackets lasted 
 for 36 minutes. The consumption of feed- water was 
 at the rate of 46 "2 5 Ibs. per indicated horse-power per 
 hour. The trial with steam in all the jackets lasted 
 for 28 minutes. The consumption of feed-water, in- 
 cluding jacket- water, was at the rate of 30*43 Ibs. per 
 indicated horse-power per hour, showing a saving in 
 feed-water of 46'25 - 30'43 = 15'82 Ibs. per indicated 
 horse-power per hour, or a decrease in the consump- 
 tion of 34'2 per cent., due to the action of steam, as 
 compared with hot air in the jackets. 
 
 The mean temperature of the internal part of the 
 cylinder wall was 31 higher with steam in the jackets 
 than without ; and for those two trials the tempera- 
 tures were a few degrees higher than in the first two 
 trials of Experiment No. 21, when the speed was about 
 double, all the other conditions being the same. The 
 total condensed water from the jackets was as 
 follows : 
 
 Jacket. Condensed water. 
 
 Body jacket, inner wall, . 0'68 Ib. per I.H.P per hour. 
 
 Body jacket, outer wall, . 0'68 Ib. 
 
 Top-end jacket, . . . 0'32 Ib. 
 
 Bottom -end jacket, . . 0'50 Ib. 
 
 Valve-chest jacket, . . 0'25 Ib. 
 
 Total jacket- water, . . 2 '43 Ibs. 
 
MR. DONKIN'S TESTS 191 
 
 The total quantity of steam condensed in the jackets 
 was therefore 2 '43 Ibs. per indicated horse-power per 
 hour, which is equivalent to *7'99 per cent, of the feed- 
 water. Thus, for every Ib. of steam condensed in the 
 jackets, there was a net saving in feed-water of 6*5 Ibs. 
 Comparing these results with the first two trials in 
 Experiment No. 21, in which all the conditions were 
 the same, with the exception of speed, the effect of 
 the steam-jackets at the reduced speed is seen to be 
 increased by about 3 Ibs. per indicated horse-power 
 per hour, thus : 
 
 Speed of Engine. Saving due to Steam-jackets. 
 
 218 revs, per minute, . 12'84 Ibs. per I.H. P. per hour. 
 116 revs, per minute, . 15*82 Ibs. ,, 
 
 Increase in saving \ 
 at reduced speed ] Z y * lbs 
 
 Experiment No. 23. Two non-condensing trials 
 with and without steam in jackets. The details of 
 this experiment are given in Table No. 23. The 
 trials were made at about full speed. With the ex- 
 ception that, in this case, there was no vacuum in the 
 condenser, all the conditions were the same as those 
 for the first two trials of Experiment No. 21. 
 
 The trial without steam in any of the jackets lasted 
 for 38 f minutes. The consumption of feed-water was 
 at the rate of 6 2 '64 lbs. per indicated horse-power per 
 hour. 
 
 The trial with steam in all the jackets lasted for 
 44 minutes. The consumption of feed-water, including 
 jacket water, was at the rate of 35'69 lbs. per indicated 
 horse-power per hour, showing a saving in feed-water 
 of 62*64 - 35-69 = 26'95 lbs. per indicated horse-power 
 per hour, or a decrease of 43'0 per cent, due to the 
 action of steam as compared with air in the four 
 
192 THE EFFICIENCY OF THE STEAM-JACKET 
 
 jackets. The mean temperature of the internal part 
 of the cylinder walls was 44 higher with steam in 
 the jackets than without. The total condensed water 
 from the jackets was as follows : 
 
 Jacket. Condensed water. 
 
 Body jacket, inner wall, . 075 Ib. per I.H.P per hour. 
 
 Body jacket, outer wall, . 0'81 Ib. 
 
 Top-end jacket, . . . 0'22 Ib. 
 
 Bottom-end jacket, . . 0'53 Ib. 
 
 Valve-chest jacket, . . 0'25 Ib. 
 
 Total jacket-water, . . 2'56 Ibs. ,, 
 
 The total quantity of steam condensed in the 
 jackets was therefore 2 '5 6 Ibs. per indicated horse- 
 power per hour, which is equivalent to 717 per cent, 
 of the feed-water. Thus, for every pound of steam 
 condensed in the jackets, there was a net saving in 
 feed-water consumption of 10*5 Ibs. Comparing 
 these two non-condensing trials with the first two 
 trials in Experiment No. 21, which were condensing, 
 and had all the other conditions the same, the useful 
 effect of the jackets was increased from 31*1 per cent, 
 to 43 '0 per cent, when the engine was worked without 
 a vacuum, thus : 
 
 Saving due to Steam-Jackets. 
 
 Engine Working, . per I.H.P. per hour. percent. 
 Condensing, . . 12'84 Ibs. 31 '1 
 
 Non-condensing, . 26 '94 Ibs. 43 '0 
 
 Experiment No. 24. Twelve trials with and without 
 steam in the jackets, at various rates of expansion. The 
 details of these trials are given in Table XXIV. They 
 were all made condensing, at a speed of 218 revolu- 
 tions per minute, and with a steam-pressure of about 
 50 Ibs. per square inch above the atmosphere. The 
 
NI VERSITY 
 MR. DONKIN'S 
 
 trials were made in pairs, jacketed and un jacketed, 
 at six different degrees of cut-off, 1-1 6th, l-12tb, 
 l-8th, 3-16ths, 5-16ths, and half-stroke, all the 
 other conditions remaining as far as possible the 
 same. 
 
 From Table XXIV. it will be seen that with the 
 greatest number of expansions, 6*8 at l-16th cut-off, 
 the saving due to the jackets was 40*4 per cent., while 
 with the smallest number of expansions, 1*8 at one- 
 half cut-off, the saving was only 23'1 per cent. ; or, 
 speaking generally, the saving in steam consumption 
 due to the use of steam-jackets increases with the 
 number of expansions. 
 
 The great difference in the temperatures of the 
 cylinder walls with and without steam in the jackets 
 is clearly noticeable ; this difference decreases con- 
 siderably as the number of expansions decreases. 
 
 At a speed of about 220 revolutions per minute, 
 the cut-off giving the minimum steam consumption, 
 the steam in jackets was found to be at l-8th of the 
 stroke, equal to 4'8 expansions. The consumption of 
 feed-water, including jacket-water, per indicated horse- 
 power per hour in this case was 25*2 Ibs. At the 
 same speed, without steam in the jackets, the best cut- 
 off was found to be at 5-16ths of the stroke, equal to 
 2*6 expansions. Here the steam used was 387 Ibs. 
 per indicated horse-power per hour. 
 
 The drier the steam at release, the greater is the 
 economy, the maximum economy being obtained with 
 the steam practically dry at release. 
 
 Experiment No. 25. To determine the effects of the 
 steam-jacket on the speed of the engine, and temperature 
 of the cylinder walls, &c. Throughout this experiment 
 the condenser was kept in action, steam was cut off 
 at 3-16ths. and the steam pressure and load on the 
 
 N 
 
194 THE EFFICIENCY OF THE STEAM-JACKET 
 
 
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MR. DONKIN'S EXPERIMENTS 
 
 195 
 
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196 THE EFFICIENCY OF THE STEAM-JACKET 
 
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MR. DONKIWS EXPERIMENTS 
 
 197 
 
 brake were kept constant. Only the body jacket was 
 used, steam being shut off from the other three. The 
 object of the experiment was to determine the effects 
 on the speed of the engine and the temperature of the 
 walls, &c., when steam was admitted to the body 
 jacket and shut off from it again without stopping the 
 engine. Starting at 11.30 A.M., after normal working 
 
 TABLE XXV. 
 
 
 
 A.M. 
 
 A.M. 
 
 P.M. 
 
 1 
 
 Time of observations, 
 
 11.41 
 
 14.47 
 
 12.37 
 
 2 
 
 Body-Jacket off or on, 
 
 off. 
 
 on. 
 
 off. 
 
 3 
 
 Steam-Jacket pressure, 
 
 
 
 
 
 Ibs. per square inch 
 
 
 
 
 
 above atmosphere . Ibs. 
 
 o-o 
 
 55-0 
 
 7'5 
 
 4 
 
 Revolutions per minute revs. 
 
 140 
 
 265 
 
 190 
 
 5 
 
 Piston speed, feet per 
 
 
 
 
 
 minute, mean . . feet 
 
 187 
 
 353 
 
 253 
 
 6 
 
 Indicated horse-power, 
 
 
 
 
 
 mean . . .I.H.P. 
 
 4-00 
 
 7'51 
 
 5-06 
 
 7 
 
 Temperature in body- 
 jacket F. 
 
 240 
 
 301 
 
 246 
 
 8 
 
 Temperature of jacket- 
 
 
 
 
 
 wall, mean . . F. 
 
 233 
 
 295 
 
 240 
 
 9 
 
 Temperature of cylinder- 
 
 
 
 
 
 wall, mean . . F. 
 
 250 
 
 284 
 
 250 
 
 10 
 
 Temperature in cylinder, 
 
 
 
 
 
 maximum . . F. 
 
 239 
 
 253 
 
 242 
 
 11 
 
 Temperature in cylinder, 
 minimum F. 
 
 235 
 
 252 
 
 240 
 
 12 
 
 Temperature in cylinder 
 
 
 
 
 
 (in steel cup) maximum F. 
 
 266 
 
 286 
 
 262 
 
 13 
 
 Temperature in cylinder 
 (in steel cup) minimum F. 
 
 253 
 
 286 
 
 261 
 
 conditions had been reached, the engine was worked 
 for eleven minutes without steam in the jacket, and 
 allowed to attain a constant speed of 140 revolutions 
 per minute, and a constant temperature of the cylinder, 
 after which, at 11.41 A.M., steam was admitted to the 
 jacket without stopping the engine. Six minutes 
 
198 THE EFFICIENCY OF THE STEAM-JACKET 
 
 afterwards, at 11.47 A.M., when the engine had 
 acquired an increased speed of 265 revolutions per 
 minute, and the temperatures had also again become 
 constant, steam was shut off from the jacket, with the 
 result that the speed and temperatures gradually 
 decreased. Fifty minutes afterwards, at 12.37 P.M., 
 the speed was found to have fallen to 190 revolutions 
 
 TABLE XXVI. Summary of Experiments carried out 
 on Single Cylinder Non-Condensing Engines. 
 
 Date. 
 
 Authority. 
 
 Type of 
 Engine. 
 
 Pressure 
 of Steam. 
 
 Ratio of 
 Expansion. 
 
 Indicated 
 Horse- 
 Power. 
 
 Gain 
 per cent, 
 due to 
 Jackets. 
 
 1846 
 
 Thomas and 
 
 
 Ibs. 
 
 
 120 
 
 8 to 10 
 
 
 Laurens 
 
 
 
 
 
 
 1859 
 
 M'Kay 
 
 ... 
 
 115 
 
 ... 
 
 ... 
 
 23-0 
 
 1867 
 
 Fletcher, W. 
 
 Portable 
 
 60 
 
 4tol 
 
 16 
 
 20-0 
 
 1869 
 
 Donkin 
 
 Beam 
 
 45 
 
 5 to 1 
 
 ... 
 
 18 to 28 
 
 1872 
 
 Cardiff Trials 
 
 Portable 
 
 80 
 
 6tol 
 
 9 to 18 
 
 23 to 27 
 
 1874 
 
 Hallaner 
 
 Corliss 
 
 73 
 
 10 
 
 101 
 
 24-0 
 
 1874 
 
 Donkin 
 
 Beam 
 
 45 
 
 2-7 to 1 
 
 4-94 
 
 21-4 
 
 1874 
 
 Donkin 
 
 Beam 
 
 45 
 
 1 
 
 8-90 
 
 14-9 
 
 1874 
 
 Donkin 
 
 Beam 
 
 45 
 
 1 
 
 5-04 
 
 11-1 
 
 1874 
 
 Cornut 
 
 Corliss 
 
 ... 
 
 18 to 21 
 
 78-9 
 
 19-5 
 
 1874 
 
 Cornut 
 
 Corliss 
 
 ... 
 
 7 to 8 
 
 136 
 
 13-8 
 
 1874 
 
 Cornut 
 
 Ingliss 
 
 
 10 
 
 ... 
 
 19-1 
 
 1875 
 
 Emery 
 
 Marine 
 
 68 : o 
 
 3-5 & 4-1 
 
 201 
 
 10-3 
 
 1878 
 
 Salt 
 
 Corliss 
 
 ... 
 
 ... 
 
 ... 
 
 14-2 
 
 1881 
 
 Meunier and 
 
 Corliss 
 
 67 
 
 ... 
 
 81 to 100 
 
 20 to 30 
 
 
 Keller 
 
 
 
 
 
 
 1881-3 
 
 Borodin 
 
 Locomotive 
 
 65 
 
 3-4 
 
 55-7 
 
 9-3 
 
 1881-3 
 
 Borodin 
 
 Locomotive 
 
 54-9 
 
 3-3 
 
 44-6 
 
 16-0 
 
 1881-3 
 
 Borodin 
 
 Locomotive 
 
 75-3 
 
 5-1 
 
 45-7 
 
 22-4 
 
 1883 
 
 Delafond 
 
 Corliss 
 
 ... 
 
 1 to 3-9 
 
 158 
 
 6-8 
 
 1883 
 
 Delafond 
 
 Corliss 
 
 
 4-4 to 7-1 
 
 171 
 
 16-8 
 
 1890 
 
 Donkin 
 
 Vertical 
 
 50 to'53 
 
 3-75 
 
 4-19 
 
 43-0 
 
 per minute ; and had the experiment been continued 
 long enough, it would have decreased to 140 revolu- 
 tions per minute, as at the commencement. Every 
 two minutes throughout the experiment, observations 
 were made of speed, jacket pressure, and the various 
 principal temperatures. 
 
 The principal results are also given in Table XXV. 
 
SUPERHEATING 
 
 199 
 
 It will be seen how quickly the temperatures in the 
 cylinder increased after steam was admitted to the 
 jacket ; and, on the contrary, how they decreased, 
 though less quickly, after the steam-supply was shut 
 off; the only heat then available being that shut into 
 the jacket-space and that remaining in the metal 
 
 TABLE XXVII. Summary of Experiments carried 
 out on Single Cylinder Condensing Engines. 
 
 Date. 
 
 Authority. 
 
 Type of 
 Engines. 
 
 Pressure 
 of Steam. 
 
 Ratio of 
 Expansion. 
 
 Indicated 
 Horse- 
 Power. 
 
 Gain 
 per cent, 
 due to 
 Jackets. 
 
 
 
 
 Ibs. 
 
 
 
 
 1842 
 
 Thomas and 
 
 ... 
 
 53 
 
 6 
 
 
 30 to 32 
 
 
 Laurens 
 
 
 
 
 
 
 1843 
 
 Combes 
 
 ... 
 
 50 to 58 
 
 20 
 
 6to7 
 
 41-7 
 
 1860 
 
 Isherwood 
 
 Vertical 
 
 55-7 
 
 5-3 
 
 1-13 
 
 31-2 
 
 1860 
 
 I sherwood 
 
 Beam 
 
 12-0 
 
 17 
 
 361 
 
 2-7 
 
 1870 
 
 Donkin 
 
 Cornish 
 
 36 
 
 4 
 
 161 
 
 12-9 
 
 1870 
 
 Donkin 
 
 Beam 
 
 45 
 
 1-8 
 
 9-3 
 
 19-4 
 
 1873 
 
 Him and 
 
 Corliss 
 
 80 
 
 10 
 
 83-1 
 
 23-7 
 
 
 Halleur 
 
 
 
 
 
 
 1873 
 
 Eennie 
 
 Beam 
 
 17 
 
 3-4 
 
 41-6 
 
 32-4 
 
 1875 
 
 Loring and 
 
 Marine 
 
 15-4 
 
 2 
 
 97-9 
 
 16-3 
 
 
 Emery 
 
 
 
 
 
 
 1877 
 
 Fletcher, L. 
 
 Marine 
 
 30 to 60 
 
 4-7 
 
 192 
 
 15-5 
 
 1878 
 
 Meunier and 
 
 Corliss 
 
 67-2 
 
 5-7 
 
 158 
 
 21-5 
 
 
 Keller 
 
 
 
 
 
 
 1878 
 
 Meunier and 
 
 Corliss 
 
 68-1 
 
 12-4 
 
 100-3 
 
 30-3 
 
 
 Keller 
 
 
 
 
 
 
 1879 
 
 Farcot 
 
 Corliss 
 
 61-8 
 
 15 
 
 166 
 
 17-1 
 
 1882 
 
 Mair 
 
 Pumping 
 
 42 
 
 4-3 
 
 123 
 
 16-6 
 
 1883 
 
 Delafond 
 
 Corliss 
 
 110 
 
 11-3 
 
 141 
 
 26-6 
 
 1883 
 
 Delafond 
 
 Corliss 
 
 110 
 
 6-4 
 
 212 
 
 20-0 
 
 1886 
 
 Guzzi 
 
 
 56-6 
 
 ... 
 
 25-5 
 
 16-8 
 
 1888 
 
 Doerfel 
 
 Corliss' 
 
 62-2 
 
 5* 
 
 159 
 
 12-3 
 
 1889 
 
 Longdridge 
 
 Corliss 
 
 61 
 
 4-2 
 
 488 
 
 2-5 
 
 1890 
 
 Unwin 
 
 Horizontal 
 
 59-61 
 
 4 
 
 37-96 
 
 17-0 
 
 1890-1 
 
 Donkin 
 
 Vertical 
 
 50-2 
 
 3-75 
 
 3-72 
 
 34-2 
 
 1890 
 
 Donkin 
 
 Vertical 
 
 49-9 
 
 6-8 
 
 4-36 
 
 40-4 
 
 of the cylinder-walls. The speed of the engine 
 decreased considerably as this heat was gradually 
 exhausted. 
 
 Superheating. Subsequent experiments' have been 
 carried out, using slightly superheated steam both in 
 the jackets and in the cylinder. With only from 
 35 to 58 F. of superheating, and using this steam 
 
200 THE EFFICIENCY OF THE STEAM-JACKET 
 
 in all four jackets as well as in the cylinder, there 
 was an economy of about 26 per cent, due to the 
 jackets, in comparison with the result obtained when 
 using the same steam in the cylinder alone, and 
 shutting off the jackets. The engine was working, 
 condensing, at l-16th cut-off, and at a speed of 200 
 revolutions per minute. The increase in temperature 
 
 TABLE XXVIII. Summary of Experiments carried 
 out on Compound Condensing Engines. 
 
 Date. 
 
 Authority. 
 
 Type of 
 Engine. 
 
 Pressure 
 of Steam 
 
 Ratio of 
 Expansion. 
 
 Indicated 
 Horse- 
 Power. 
 
 Gain 
 per cent, 
 due to 
 Jackets. 
 
 1855 
 
 Him 
 
 Beam 
 
 55-8 
 
 4-3 
 
 102-6 
 
 23-5 
 
 1859 
 
 Donkin 
 
 Beam 
 
 41-0 
 
 5-5 
 
 19-8 
 
 28-6 
 
 1868 
 
 Donkin 
 
 Beam 
 
 40-9 
 
 11 
 
 46-2 
 
 31-2 
 
 1870 
 
 Donkin 
 
 Beam 
 
 45-0 
 
 10-3 
 
 16-5 
 
 38-6 
 
 1874 
 
 Emery 
 
 Marine 
 
 80-3 
 
 7 
 
 99-2 
 
 11-7 
 
 1875-81 
 
 Donkin 
 
 Tandem 
 
 42-0 
 
 8-5 
 
 7-86 
 
 25-5 
 
 1875-81 
 
 Donkin 
 
 Tandem 
 
 42-0 
 
 9-0 
 
 9-89 
 
 29-0 
 
 1875-81 
 
 Donkin 
 
 Tandem 
 
 42-0 
 
 9-3 
 
 9-46 
 
 33-9 
 
 1881 
 
 Mail- 
 
 Beam 
 
 47-3 
 
 15-8 
 
 75-2 
 
 34-9 
 
 1887 
 
 Kennedy and 
 
 Vertical 
 
 80 
 
 7 
 
 168 
 
 15-4 
 
 
 Donkin 
 
 
 
 
 
 
 1887 
 
 Kennedy 
 
 Tandem 
 
 82-1 
 
 11-10 
 
 8-45 
 
 35-2 
 
 1887 
 
 Kennedy 
 
 Tandem 
 
 94 
 
 8-43 
 
 13-03 
 
 38-2 
 
 1888 
 
 Mair Rumley 
 
 Beam 
 
 49 
 
 
 168 
 
 8-6 
 
 1890 
 
 Ollgaard 
 
 Beam 
 
 51-25 
 
 14-6 
 
 81-2 
 
 18-6 
 
 1890 
 
 English Davey 
 
 Horizontal 
 
 50-2 
 
 12-6 
 
 113-4 
 
 19-0 
 
 
 and Co. 
 
 
 
 
 
 
 1891 
 
 Denton 
 
 ... 
 
 150 
 
 15 
 
 ... 
 
 20-0 
 
 
 Triple Expansion Engines. 
 
 1889 
 
 Reynolds 
 
 Vertical 
 
 192 
 
 26-5 
 
 72-1 
 
 17-4 
 
 1889 
 
 Davey and 
 
 Vertical 
 
 130 
 
 30 
 
 138-0 
 
 10-3 
 
 
 Bryan 
 
 
 
 
 
 
 of the cylinder- walls when the jackets were in use 
 was about 50 F. 
 
 Conclusions. With the same quality and tempera- 
 ture of steam in these experiments, the hotter walls 
 yielded the better results. With walls of the same 
 temperature, the drier and hotter the steam the greater 
 
ME. COMBE'S EXPERIMENTS 201 
 
 was the economy. The best result with all the jackets 
 in use was obtained with l-8th cut-off, or 4*8 expan- 
 sions ; the consumption was 25 '2 Ibs. of steam per 
 indicated horse-power per hour, including jacket- 
 water ; and the dryness-fraction at release was 96*6 
 per cent., showing that, in this case, the exhaust 
 steam was practically dry, and neither superheated 
 nor wet. 
 
 We now give Tables XXVL, XXVIL, and XXVIIL, 
 which show at a glance the percentage of economy 
 gained by thorough steam-jacketing in all types of 
 engines during the last fifty years. It will be seen 
 from this summary of results that, whether the 
 engines have been simple or compound condensing, 
 or non-condensing, of large or small proportions at all 
 pressures and rates of expansion, where jackets have 
 been properly applied and tested, an increased economy 
 has resulted therefrom. 
 
 "We shall bring our remarks to a close by referring 
 to the use of steam of a higher pressure for supplying 
 the jackets than that used in the working cylinder. 
 The employment of high-pressure steam for jacketing 
 is not a modern idea. Mr. Combe, in 1843, " first 
 noticed the condensation on admission, which he 
 believed could be prevented by exposing the cylin- 
 der to a greater heat than that supplied by the 
 boiler."^ 
 
 While many engineers have proposed the adoption 
 of high-pressure steam for use in the jackets, Mr. P. 
 G-uzzie, an Italian engineer, has recently put the 
 system to a test. He generates steam for the jackets 
 in a Perkins' type of boiler, steam of 220 Ibs. pressure, 
 having a temperature of 390 F., being used. The 
 condensed steam from the jackets is drained back into 
 
 * Mr. J. C. Hair. 
 
202 THE EFFICIENCY OF THE STEAM-JACKET 
 
 the boiler. Two comparative tests show the advan- 
 tages of the arrangement : 
 
 
 Jacket Press, 
 
 Jacket Press, 
 
 
 176 Ibs. 
 
 56 Ibs. 
 
 Date of experiment, 
 
 24 Feb., 1886 
 
 20 Feb., 1886 
 
 Duration of test, .... 
 
 6 hrs. 18 min. 
 
 7 hrs. 11 min. 
 
 Boiler pressure, per square inch, . 
 
 56 Ibs. 
 
 56 Ibs. 
 
 Mean indicated horse-power, 
 
 25-9 
 
 25-67 
 
 Water used per indicated horse- 
 
 
 
 power per hour, . , 
 
 19-6 Ibs. 
 
 28-5 Ibs. 
 
 The first was made with a steam pressure of. 12*75 
 atmospheres in the jacket ; the second with boiler 
 steam in the jacket. The engine was one of 50 
 effective horse-power, with a single cylinder and 
 condenser, an arrangement most conducive to excessive 
 condensation or loss of steam in the cylinder, especially 
 when working with a small admission of steam to less 
 than half its power, and under these circumstances a 
 consumption of 19'6 Ibs. of steam per indicated horse- 
 power per hour is a very good result. 
 
 In any case, there is a difference of 17 per cent., 
 not between jacketed and unjacketed cylinders, but 
 between high-pressure and boiler-pressure steam 
 employed in the jacket. The advantage of this 
 principle is thus clearly demonstrated, and the applica- 
 tion in a similar way could in many instances be easily 
 carried out. Mr. Thurston says : " The final results 
 of experience up to date, may be summed up in the 
 statement that, when a jacket is properly designed, 
 constructed, and attached, and when itf is properly 
 manipulated, it may always be expected to give good 
 economical results." 
 
APPENDIX. 
 
 IN order to realise the utmost economy from steam-jacketing, 
 it is absolutely necessary that the engine should be provided 
 with several appliances that will help to secure these 
 results. It may be useful to refer to some of these at 
 greater length than we were able to do in the body of the 
 book. 
 
 We purpose also in this place to make a few observations 
 on some other appliances for economising steam, apart from 
 steam-jacketing altogether, in the hope that these notes will 
 enhance the value of the book. 
 
 We have urged the importance of providing the engines 
 with dry steam, both for the supply of the steam-jackets 
 and the working cylinders. Messrs. M'Phail & Simpson's 
 Steam Generator and Superheater has, in some severe tests, 
 proved itself to be the needful apparatus for thoroughly 
 drying the steam. By its use the enormous losses arising 
 from the use of wet or sloppy steam will be prevented (see 
 p. 57). 
 
 Another useful appliance is Mr. J. Royle's Water Se- 
 parator fitted with an expansion trap. This combined 
 apparatus intercepts and discharges the water arising from 
 condensation in the steam pipes, and ensures dry steam 
 only passing to the cylinder of the engine. Heavy wet 
 steam is well known to materially interfere with economical 
 use in the cylinder. Another advantage arising from the 
 use of the Separator is that all knocking in the cylinder is 
 avoided, owing to the presence of water between the piston 
 and the cylinder-cover; a fertile source of many break- 
 downs. All bursting of joints through the pipes being 
 water-logged on starting is also avoided. 
 
204 APPENDIX 
 
 No steam-jacketed cylinder can be complete unless it is 
 provided with a reliable steam-trap. We have had several 
 years' experience with Messrs. Lancaster & Tonge's Steam- 
 traps, and can recommend them. Let it be remembered 
 that a steam-jacket is worse than useless unless it is 
 thoroughly drained. 
 
 Another steam-trap is the " Syphonia," made by Mr. J. 
 Royle : this trap also gives good results, and has several 
 special features of advantage that are well worthy of 
 careful notice by steam-users. 
 
 United States Metallic Packing. 
 
 Messrs. Llewellin & James are the makers of Farrar's 
 steam-trap, from the use of which we have heard some good 
 accounts. 
 
 The Return Steam-trap, made by Messrs. Dawson and 
 Co., not only clears the steam pipes or steam-jackets of 
 water, but returns this hot water to the boiler, which is a 
 clear saving, as we have stated in another place (see 
 p. 117). 
 
 The chief objection arising from the employment of 
 superheated steam is the trouble experienced with the 
 ordinary packing used in the stuffing-boxes for the piston- 
 
APPENDIX 205 
 
 and valve-rods. But this trouble is entirely removed 
 by the adoption of the United States Metallic Packing. 
 It is very evident that superheated steam will again be 
 thoroughly put to the test on many types of engines, so 
 that a larger demand for this packing will be experienced 
 (see illustration). 
 
 Messrs. Green & Son's Economiser is so well known and 
 largely adopted that little need be said in its favour. 
 Wherever one or any number of boilers of the Cornish, 
 Lancashire, or other types (which are set in brickwork) 
 are adopted, the economiser should be fixed so as to heat 
 the feed-water to a high temperature by the waste flue 
 gases in their exit to the chimney-stack, thereby effecting 
 a considerable saving in coal (see p. 58). 
 
 In non-condensing engines the feed- water can be heated 
 to nearly boiling point by means of the exhaust steam, 
 previous to its discharge into the atmosphere. Messrs. 
 Shore & Son's Heater is suitable for this purpose. In some 
 jet-condensing engines we have fixed a water-heater between 
 the cylinder and the condenser, so that the exhaust steam 
 in its passage was made to traverse through the heater ; the 
 feed-water being forced through the heater in the usual 
 manner. 
 
 Another method of utilising the exhaust steam, so as to 
 effect considerable economy, cannot be secured more easily 
 than by the application of the now well-known and appre- 
 ciated Exhaust Stearn Injector, made by The Patent 
 Exhaust Steam Injector Coy. One user says : " During 
 my forty years' experience with all sorts of boiler feeders, I 
 have never known anything to equal the Exhaust Steam 
 Injector." It can be used on boilers working at high 
 pressures ; it removes back pressure in the engine cylinder ; 
 forces the feed- water into the boiler at a high temperature ; 
 and is a most economical and reliable steam-saving appliance. 
 
 We are very pleased to be able to call attention to 
 Messrs. Whyte & Cooper's Evaporative Condenser. This 
 system of condensation is invaluable where the supply of 
 water is limited or costly, a good vacuum being maintained 
 with a consumption of water which is altogether unattain- 
 able by any other method of condensation. 
 
206 APPENDIX 
 
 With regard to the saving in coal, or in steam used per 
 indicated horse-power, say, for example, a simple high- 
 pressure engine uses 34 Ibs. of steam per indicated horse- 
 power per hour ; by the addition of a condenser the weight 
 of steam is reduced to 24 Ibs. per indicated horse-power per 
 hour, the engine doing quite the same work as before, with 
 a coal saving of 30 per cent. ; but then the water required 
 for the condenser to suit this case would only be 18 Ibs. 
 per indicated horse-power per hour, so that a saving in 
 water of 47 per cent, would be effected. With the high- 
 pressure engines 34 Ibs. of water, in the shape of exhaust 
 steam, is blown away as waste per indicated horse-power ; 
 with the condenser 1 8 Ibs. is evaporated from the condenser 
 per indicated horse-power. 
 
 One correspondent says : " The Evaporative Condenser 
 uses very little water, gives a good hot engine-feed, and the 
 vacuum averages at least 26 J inches. To-day the vacuum 
 stands at 28 inches. I wish I had got your Cooler a few 
 years sooner, as I should have saved by it a great deal of 
 money which I could ill afford to lose." 
 
 Wherever water is scarce and fuel expensive these simple 
 condensers shall be adopted. 
 
 There are steam-engines in every neighbourhood, the 
 economy of which is capable of being vastly improved. In 
 many of these cases it would pay a good percentage to 
 apply Dr. Proell's Patent Automatic Expansion Appara- 
 tus to the engines. It is easily applied to existing slide- 
 valve engines, and special forms are made for newly-built 
 engines, which are thereby made equal in regularity of 
 speed and economy of steam to the best Corliss engines. 
 
 In a previous part of the book we have recommended the 
 use of Phosphor-Bronze for steam-jacketed cylinder liners. 
 We believe that a considerable saving would accrue from 
 the use of these phosphor-bronze liners : they can be made 
 as hard as desirable, the material gives a smooth surface, 
 while its conductivity is more than three times as great as 
 that of cast iron. We have used phosphor-bronze slide- 
 valves with excellent results. It is impossible to name the 
 many purposes to which this metal is now applied (see 
 p. 126). 
 
APPENDIX 207 
 
 We have to notice two distinct arrangements of forced 
 draught ; this is an appliance that has come to the front 
 during recent years. Mr. Granger's Forced Draught can 
 be applied to all classes of boilers, and will increase their 
 steaming capacity from 20 to 25 per cent. The saving 
 effected by Granger's system of forced draught may be put 
 as follows : The average of several experiments has shown 
 that one ton of cheap fuel, such as slack, smudge or small 
 coal of fair heating power, will raise as much steam when 
 urged with a forced draught as one ton of good steam coal 
 will raise with ordinary draught. Now, as the one fuel is 
 from 40 to 50 per cent, cheaper than the other, there is a 
 gross saving to that extent, and from this must be deducted 
 a small percentage for the steam consumed in working the 
 nozzles. In cases where the boiler power is greatly de- 
 ficient, ordinary small steam coal may be used, which, with 
 the powerful draught, will increase the steaming capacity 
 from 20 to 25 per cent. 
 
 The second system of Forced Draught we have to notice 
 is Messrs. Meldrum Bros. This firm has been for some 
 time closely identified with the advances made in the 
 profitable use of inferior fuel in boiler furnaces. Undoubt- 
 edly their system of forced draught has been very largely 
 employed. 
 
 The firebars used have air-spaces less than J inch in 
 width, so that nothing but the finest dust can fall through. 
 In many cases it has been found possible to dispense with 
 one or two out of a range of boilers, in consequence of the 
 increased evaporation obtained from the others. A great 
 point is that the draught is forced, and is perfectly under 
 control. Any kind of waste fuel can be burned to advan- 
 tage. " In some cases, v says The Mechanical World, "under 
 special conditions the economy effected has been most 
 remarkable, notably in the care of the West Hartlepool 
 Iron and Steel Coy., who formerly used to send refuse out 
 to sea at a cost of about Is. 6d. a ton. This now suffices 
 to raise all the steam required in the works." 
 
 Messrs. Meldrum Bros, have 2300 of these furnaces at 
 work, which speaks for itself. 
 
 Feed- Water Filters are coming into general use, and are 
 
208 APPENDIX 
 
 found to be most beneficial. The one made by Messrs. 
 Copley, Turner & Co. may with confidence be recommended. 
 
 The filter removes grease, metallic oxides, and other 
 objectionable materials found in feed- water. By its use the 
 burning and collapsing of furnaces is prevented ; its use also 
 serves to reduce the quantity and thickness of the scale ; 
 and the removal of these non-conductive deposits causes a 
 considerable economy of fuel. 
 
 In another part of the book we have spoken very highly 
 of the cylinder and jacketing arrangements carried out by 
 M. Bollinckx. We must admit that the design, workman- 
 ship, and efficiency of these engines are worthy of all 
 praise. M. Bollinckx's productions have been most favour- 
 ably noticed in recent issues of The Engineer. The firm 
 deservedly enjoys a very high reputation for the excellence 
 of the work turned out. 
 
 In these days of scientific inquiry, when nothing appears 
 to be taken for granted, no steam user of any importance 
 can afford to be without a steam-engine indicator. There 
 are doubtless hundreds of engines which are considered by 
 their owners as being fairly economical, which, if indicated, 
 would prove themselves to be anything but economical : many 
 of these engines could be improved without much expense. 
 Engines should always be indicated after alterations and 
 repairs. It is necessary that steam users should know the 
 amount of power absorbed by the engine and the shafting : 
 this can readily be ascertained by taking a friction diagram. 
 The indicator will show the amount of back-pressure in the 
 cylinder ; it will show any wire drawing owing to contracted 
 steam-ports or small steam pipes ; it will reveal defective 
 valve-setting and many other faults of construction that we 
 cannot stay to name. If the information received from the 
 cards of a properly used indicator be acted upon, this 
 instrument may then be termed a steam economiser. 
 Messrs. Hopkinson & Coy.'s Indicator is a reliable instru- 
 ment, and is used by a large number of engineers. 
 
 There is one more essential steam economising agent that 
 must not be overlooked. It is very necessary that a perfectly 
 steam-tight piston should be used, and being tight it must 
 also be as near frictionless as possible. A leaking piston 
 
APPENDIX 209 
 
 in a simple engine is a direct source of loss. In compound 
 engines the leakage from the high-pressure piston is not 
 lost, but does some work in the low-pressure cylinder. But 
 a leaking piston is an inexcusable waste of fuel; because the 
 remedy is so easily effected. Messrs. Lancaster & Tonge 
 have made this subject their particular study with good 
 results. While on the question of pistons, we may quote 
 some remarks made by Mr. Butterworth recently : " Before 
 leaving the subject of steam-jackets, it may be said that 
 they have an important bearing on the efficient lubrication 
 of a cylinder. It is well known that most metals when 
 working together under water actually generate more friction 
 than when working dry, so that if a film of water be already 
 present, it will prevent the oil adhering to the walls of 
 the cylinder, and cause increased wear. The following may 
 be taken as an indirect proof of this. In the high-pressure 
 cylinder of a marine engine 22 inch, diameter, 36 inch. 
 stroke, running 150 revolutions per minute, a set of piston 
 rings were fitted, and, after working twelve months, were 
 overhauled and found to have scarcely worn at all, although 
 the steam-pressure was 160 Ibs. per square inch. At the 
 same time, by the way, the boilers of the ordinary tubular 
 marine type were thoroughly scraped and cleaned, with the 
 result that the steam was more rapidly generated on the 
 next voyage, causing priming to ensue, with the result that 
 the piston rings were worn out in three weeks. All the 
 conditions were the same, so that it leaves no doubt that 
 the water washed the oil from the cylinder walls and took 
 its place, causing the rings to gall and wear away rapidly."* 
 As steam-pressures increase, the use of balanced slide- 
 valves will become more general. Messrs. Lancaster and 
 Tonge's Serpent Coil is specially adapted for piston-valves, 
 the peculiarity of which is, that they work over ports, the 
 steam thus acting on the outer circumference of the rings 
 and tending to close them in. If the* steam is able to do 
 so, the piston valve will then leak and cause great loss. By 
 means of the Serpent Coil the makers guarantee to obtain a 
 resistance to collapse of over 200 Ibs. per square inch, and, 
 at the same time, have an outward pressure to compensate 
 
 * The Practical Engineer, 21st December 1894. 
 
 O 
 
210 APPENDIX 
 
 for wear of less than 3 Ibs. per square inch. The Serpent 
 Coils have worked in some instances for two years without 
 showing signs of wear. 
 
 There are other means of saving fuel besides the ones we 
 have touched upon, but we cannot stop to name them. 
 
 We have dwelt upon the principal methods of economis- 
 ing steam in engines and boilers. The book has been 
 written in the hope that some of the iniquitous waste of 
 coal, that now, alas, is constantly taking place, may be pre- 
 vented : should our remarks bear fruit we shall be rewarded. 
 
ADVERTISEMENTS 
 
 211 
 
 GRANGER'S 
 
 FORCED DRAUGHT. 
 
 Can be applied to all 
 classes of Boilers, and will 
 increase their steaming 
 capacity 20 to 25 per cent. 
 
 All Steam Users 
 
 having over- 
 worked Boilers 
 will derive great 
 benefit from 
 this system. 
 
 it also burns SLACK, DUST COAL, REFUSE 
 
 FUEL, &C., to great advantage, thus 
 
 REDUCING THE COST OF RAISING STEAM 
 25 TO 5O PER CENT. 
 
 It also preserves the firebars and prevents clinker adhering. 
 The Blast is produced by Granger's Patent Adjustable Compound. 
 Blowing Nozzle. 
 
 (The only Scientific Steam Jet.) 
 
 Adopted by II. M. Govern-! 
 ment, and by most of the 
 leading Ironworks, Col- 
 lieries, Mills, Factories, 
 V< ., throughout the United 
 Kingdom. 
 
 102 
 
 WM. B. GRANGER, 
 
 BROOKE-ROAD, STOKE NEWINGTON, 
 
 LONDON, N. 
 
INDEX. 
 
 Abuse of the steam-jacket, 88, 
 
 139, 145. 
 
 Actual expansion curves, 40. 
 Adam's diagram, 39. 
 Admiralty service, 126. 
 Air-jackets, 112, 113. 
 Air-spaces, 25, 142. 
 Allen, 126. 
 American cylinders, 95, 96, 98, 
 
 135. 
 
 American Navy, 154. 
 A. M. in engineering, 149. 
 American mine, 25. 
 Anderson, 47. 
 Appendix, 56, 57, 138. 
 Approved design, 101. 
 Approved exhaust outlet, 102. 
 Ashes in jacket, 2. 
 Automatic expansion gear, 206. 
 Aveling and Porter, 58, 59. 
 
 Babcock, 63. 
 
 Babcock and Wilcox, 86. 
 
 Bache, 164. 
 
 Badly-fitting liner, 143. 
 
 Barrett, 126. 
 
 Bayles, 25. 
 
 Beattie's patent, 95. 
 
 Behaviour of steam in cylinders, 
 
 35. 
 
 Berger Andre & Co., 170. 
 Bismuth, 63. 
 Boat engines, 67. 
 Boiler trials, 42, 43. 
 Bollinckx's cylinders, 109, 110, 
 
 114. 
 
 Bollinckx's steam engines, 208. 
 Borodin, 198. 
 Boulton, 2. 
 
 Box's treatise on heat, 22. 
 Bramwell, Sir Fred., 48, 71, 77, 
 
 146, 176. 
 
 Bright surfaces, 137. 
 British navy, 154. 
 Bryan, 184. 
 Bull's metal, 232. 
 Bury St. Edmunds, 16. 
 Butterworth, 209. 
 
 Cambridge's portable engine, 13, 
 
 98. 
 
 Cardiff engine trials, 161, 162. 
 Carlisle show, 15. 
 Cassier's magazine, 114, 116. 
 Cement jacket, 143. 
 Chacewater, 3. 
 Chamberlain, 64. 
 Chatham Waterworks, 174. 
 Clark, D. K., 21, 31, 34, 134. 
 Clausius, Prof., 50. 
 Clayton and Shuttleworth, 13, 99. 
 Clearance, 131. 
 Coath, 148. 
 Combe, 156, 201. 
 Combined diagram, 82. 
 Common road locomotive, 9. 
 Compound engine, 121. 
 Compound portable engine, 122, 
 
 124. 
 Compound tramway locomotive, 
 
 132, 133. 
 Compression, 70. 
 Gomstock Lode, 25. 
 Conduction, 19, 23. 
 Copley, Turner & Co., 208. 
 Copper cylinder, 2. 
 Corliss engine, 77, 97, 103, 126, 
 
 131, 135, 168, 176. 
 
214 
 
 INDEX 
 
 Cornish engine, 104, 136. 
 Cornish pumping-engine, 7, 11, 
 
 28. 
 
 Cotton-wool, 25. 
 Cowper, 16, 32, 51, 76, 80. 
 Cracked cylinders, 101, 126. 
 Creusot Works, 177. 
 Croll's suggestions, 49, 65, 75, 
 
 84. 
 
 Crystal Palace, 21. 
 Cylinder cards, 54. 
 Cylinder condensation, 19, 29, 
 
 33. 
 Cylinder covers, 128, 131, 136. 
 
 Davey, 56, 184. 
 Dawson & Co., 204. 
 Day's diagram, 36, 37. 
 Defective construction, 89, 139, 
 
 151. 
 
 Deficient circulation, 112. 
 Deficient drainage, 119. 
 Delaford, 177. 
 Diagram from compound engine, 
 
 80. 
 
 Diagram from Corliss engine, 77. 
 Diagram from pumping-engines, 
 
 46, 47, 48. 
 Diagram from small engines, 39, 
 
 40, 52. 
 
 Diagram from Woolf engine, 79. 
 Donkin, Mr. Bryan, 87, 157, 159, 
 
 161, 162, 165, 168, 177, 180, 
 
 185, 198, 199, 200. 
 Double-beat valves, 84. 
 Drain pipes, 7, 53, 110, 116, 123, 
 
 129. 
 
 Dry diagram, 49. 
 Dry steam, 42, 51, 75, 107. 
 Duke of Hamilton, 2. 
 Dummy jacket, 142. 
 
 East London "Waterworks, 184. 
 
 Economical temperature of cylin- 
 der walls, 87. 
 
 Economical use of steam, 84. 
 
 Editor of "Engineering," 91, 106. 
 
 Editor of "The Engineer,*' 30, 
 33, 52, 125. 
 
 Efficiency of the steam-jacked, 
 153. 
 
 Efficient steam-jacketed cylinder, 
 99, 117, 119, 123. 
 
 Emery, 63, 165, 198. 
 
 Engine and boiler trials, 43. 
 Engine-driver, 111. 
 Engine-maker, 71. 
 Engine-room, 146. 
 " Engineer, The," 57, 58, 60, 61, 
 
 73, 110, 140. 
 
 "Engineering," 114, 118, 163. 
 "Engineering" correspondent, 
 
 112. 
 "Engineers' Guide," 79, 107, 
 
 123, 155. 
 
 English, Mr., 200. 
 Evaporative condenser, 205. 
 Evaporative tests, 42. 
 Exhaust jacket, 94, 95, 143. 
 Exhaust passages, 93, 96, 97, 98. 
 Exhaust steam injector, 205. 
 Engineer-in-chief, 149. 
 Engines for pumping, 44, 47, 54, 
 
 151. 
 
 Fairbairn Engineering Co., 155. 
 
 Farcot, 199. 
 
 Farey, 154, 157, 159, 180. 
 
 Farrar's steam trap, 204. 
 
 Faulty casting, 141. 
 
 Faulty designing, 88, 92, 97, 103, 
 
 104. 
 
 Faulty exhaust outlet, 97, 100. 
 Faulty jacket drain, 129. 
 Feed-water filter, 207. 
 Flay craft, 13. 
 
 Fletcher, Lavington, 128, 199. 
 Fletcher, William, 198. 
 Forced draught, Granger's, 207 ; 
 
 Meldrum's, 207. 
 Foster, 10. 
 Frikart compound engine, 121. 
 
 Galatz, 146. 
 
 Glasgow trials, 51. 
 
 Glass tube, 76. 
 
 Glass cylinder, 65. 
 
 Good cylinder drainage, 69. 
 
 Good non-conductors, 26. 
 
 Goodman, Prof., 82. 
 
 Granger's forced draught, 207. 
 
 Green's economiser, 58, 205. 
 
 Grose, 11. 
 
 Guzzie, 199, 201. 
 
 Haake, 26. 
 
 Haeder & Powles, 124. 
 
 Halpin's cylinder, 115, 127, 128. 
 
INDEX 
 
 215 
 
 Hair-felt, 25. 
 
 Halleur, 199. 
 
 Hartnell, 83. 
 
 Headley, 94. 
 
 Hick, Hargreaves & Co., 167. 
 
 Hill, 64. 
 
 Him, 199, 200. 
 
 History of the steam-jacket, 1. 
 
 "Holmes on the steam-engine," 
 
 56, 88, 165. 
 
 Hopkinson's Guide, 79, 123, 155. 
 Hopkinson's Indicator, 208. 
 Hornsby & Sons, 13, 99. 
 Hot-air jackets, 55, 57. 
 Hot- water jackets, 55, 58, 59. 
 
 Inattentive engine-drivers, 145. 
 Initial condensation, 33. 
 Internal condensation, 29, 34, 55, 
 56, 60. 
 
 Jacket drainage, 117, 130. 
 Jacket water, 190. 
 Jacketed covers, 129, 131. 
 Joule, Prof., 132. 
 
 Keller, 198. 
 
 Kennedy, Prof., 62, 177, 182, 
 200. 
 
 Lagging for cylinders, 21, 26, 74, 
 
 135. 
 Lancaster & Tonge's steam traps, 
 
 204 ; piston springs, 208. 
 Large compound engine, 80. 
 Large exhaust port, 102. 
 Large pumping^engines, 44, 173. 
 Large steam-chest, 133. 
 Lead-covered pistons, 61. 
 Leroy's composition, 27. 
 Liners not tight, 143, 144. 
 Liners of phosphor-bronze, 1 25. 
 Liners with heat ribs, 127, 128. 
 Linseed oil, 63. 
 Llewellin & James, 204. 
 London Pumping Station, 177. 
 Longdridge, 103, 199. 
 Loring and Emery, 199. 
 Losses from external radiation, 19. 
 
 Maggs, 15. 
 
 Mair, 113, 171, 174, 200. 
 Mair Rural ey, 200. 
 Marine boilers, 49. 
 
 Marine engines, 128, 148, 163. 
 
 Martini, 14. 
 
 Maudsley's engine, 10. 
 
 Maw, 118. 
 
 M'Intoch & Co., 114. 
 
 M'Laren's engine, 81, 83. 
 
 M'Laren's paper, 42. 
 
 MThail & Simpson, 57, 203. 
 
 Mechanical Engineers, Institu- 
 tion of, 62, 76, 175. 
 Mechanical World," 64, 84, 
 175. 
 
 Meddlesome engine-drivers, 147. 
 
 Meldrum's forced draught, 207. 
 
 Meneuer and Keller, 198, 199. 
 
 Metallic packing, 56. 
 
 Meyer's expansion gear, 182, 184, 
 185. 
 
 Most economical temperature, 87. 
 
 Mudd, Mr., 49. 
 
 Murdock's boring machine, 2. 
 
 Murdoek's cylinder, 7. 
 
 Murdock's road locomotive, 7, 
 98. 
 
 Naked cylinder, 22. 
 Napier & Sons, 150. 
 Neglected drainage, 116. 
 Newcastle trials, 41, 42. 
 Newcomen, 1, 5. 
 Newton, 16. 
 New York, 114. 
 Non-absorber of heat, 59. 
 Non-conducting composition, 22, 
 
 26, 27, 61. 
 Non-conducting cylinders, 55, 59, 
 
 60, 62. 
 Non-conducting materials, 19, 
 
 20, 25, 59, 61, 65, 134. 
 Non-conductor, 22, 59, 65. 
 Non-condensing engine, 36, 198. 
 Non-condensing trials, 187, 191, 
 
 192. 
 
 Non-jacketed cylinders, 95. 
 Non-radiating materials, 19, 20. 
 Non-radiation, 22, 25, 26. 
 Norm and, 15. 
 Northcott, 58, 73, 75, 88, 107, 
 
 109. 
 Notions on jacketing, 89. 
 
 Objects and methods of engine 
 
 trials, 76. 
 Occasional blowing out, 122. 
 
216 
 
 INDEX 
 
 Oil jackets, 9, 67. 
 
 Oil, linseed, 63. 
 
 Oily acids, 64. 
 
 Old Hand, 146. 
 
 Ollgaard, 200. 
 
 Ordway, 25. 
 
 Outside cylinders, 31, 35, 96. 
 
 Outside casing, 142. 
 
 Oven dryness, 100. 
 
 Owens College, 183. 
 
 Oxford Show, 16, 21. 
 
 Paddle-engine, 66. 
 
 Paisley, 103. 
 
 Parsons, 13. 
 
 Peclet, 23, 24. 
 
 Penn's Mill, 154. 
 
 Perkins' heating apparatus, 59. 
 
 Philadelphia Exhibition, 135. 
 
 Phillips, Mr., 129. 
 
 Phosphor bronze liners, 206. 
 
 Pickled in sal-ammoniac, 143. 
 
 Pinchbeck, 155. 
 
 Plymouth engine trials, 37, 39, 
 
 42, 134. 
 
 Polished cylinder covers, 65, 87. 
 Polished pistons, 65, 75, 87. 
 Portable engines, 13, 15, 16, 118, 
 
 157, 161, 162. 
 Portable engine-cylinders, 111, 
 
 116, 123. 
 
 Portable engine-makers, 113. 
 Porter's cylinder, 99. 
 Powles, Mr., 124. 
 Practical Engineer, 36. 
 Prize engines, 161. 
 Proell's expansion gear, 206. 
 Proof of efficiency, 153. 
 Puffing Billy, 10, 94. 
 Pumping-engine, 11, 45, 47, 151, 
 
 156, 161, 173, 174, 182. 
 Pumping Station, 177, 184. 
 
 Radiation, 19, 20, 24, 27, 74, 
 
 77. 
 
 Rankinised diagram, 80. 
 Rankin, Prof., 33, 50, 53. 
 Rapid conducting power, 29. 
 Redruth, 7. 
 Rennie, 199. 
 
 Research Committee, 103, 175. 
 Return steam-trap, 138, 204. 
 Revue Industrielle, 27. 
 Reynolds, 200. 
 
 Rich, Mr., 45, 48, 54, 150, 161, 
 
 174, 181, 182. 
 Robey, 16, 69. 
 Royal Agricultural Show, 15, 16, 
 
 21, 37, 161. 
 
 Royle's steam-trap, 204. 
 Royle's water separator, 203. 
 Russell, Scott-, Mr., 154. 
 
 Safety valves, 113, 123. 
 
 Saltaire, 155. 
 
 Salt, Sir Titus, 155, 167. 
 
 Sawdust, 27. 
 
 Schichau, 114. 
 
 Schonheyder, 104. 
 
 Second Report, &c., 177. 
 
 Serpent coil, 209. 
 
 Ship's winches, 21. 
 
 Shore & Son's heater, 205. 
 
 Simpson & Co., 172. 
 
 Simpson, Strickland & Co., 40. 
 
 Slate facings, 65. 
 
 Slow-moving engines, 31. 
 
 Small steam-engines, 134. 
 
 Smeaton's pistons, 61. 
 
 Stapfer on jackets, 91. 
 
 Starch, 27. 
 
 Steam-chests, 133. 
 
 Steam-collectors, 138, 203. 
 
 Steam-cranes, 21. 
 
 Steam-engine, theory and action 
 
 of, 58, 74, 107. 
 
 Steam -jacketed covers, 129, 131. 
 Steam-jacket an economiser, 17. 
 Steam-jacket efficient, 119, 137. 
 Steam-jacketed piston, 15, 129. 
 Steam-jacket, value of, 175. 
 Steam-pipes, 107, 111, 122. 
 Steam separator, 75. 
 Steam-trap, 117, 138. 
 Steamers, 149. 
 Steamship companies, 147. 
 Steel-sheets, 26. 
 Sturgeon, 68. 
 Sulzur Bros., 28, 42, 49, 67, 76, 
 
 84, 87. 
 
 Superheated steam, 55. 
 Superheating apparatus, 57, 203. 
 Supply pipes, 102, 113, 147. 
 "Syphonia " steam trap, 204 
 
 Taylor, 80. 
 
 Text-books on the steam-engine, 
 35. 
 
INDEX 
 
 217 
 
 Theory and action of steam-engine, 
 
 58, 74, 107. 
 
 Thorough steam-jacketing, 75. 
 Thread Works, Paisley, 103. 
 Thurston's proposals, 63. 
 Thurston's remarks, 202. 
 Torpedo boat engines, 67. 
 Traction engine cylinders, 94, 96, 
 
 112, 136. 
 
 Traction engine trials, 71. 
 Tramway locomotive cylinder, 
 
 132, 133. 
 
 Treatise on heat by Box, 22. 
 Tredgold's notions, 17, 71, 153. 
 Trevithick's cylinder, 9. 
 Trevithick's locomotive, 98. 
 Trials at Glasgow, 52. 
 Trials at Newcastle, 41. 
 Trials at Wolyerhampton, 71. 
 Trials by Borodin, 198. 
 Trials by Combes, 156, 201 ; 
 
 Cornot, 198 ; Donkin, 156, 
 
 157, 159, 161, 162, 165, 182, 
 
 185 to 200 ; Emery, 164 ; Un- 
 
 \vin, 39 ; Mair, 171 ; Kennedy, 
 
 177, 182. 
 
 Trials by Farey, 154, 157, 159, 
 180; Fletcher, 198, 199; 
 
 Guzzie, 199, 201 ; Him, 156 ; 
 
 Isherwood, 199 ; Loring, 199 ; 
 
 Longdridge, 103 ; Napier, 163. 
 Trials of engines at Cardiff, 161. 
 Trials of engines at Plymouth, 
 
 39, 134. 
 Triple expansion engines, 75, 81, 
 
 84, 183, 185. 
 
 Troublesome cylinders, 141. 
 Tubular boilers, 42. 
 Turned pistons and cylinder 
 
 covers, 55. 
 
 Tuxford's portable engine cylin- 
 ders, 15. 
 Tyndall, 11. 
 
 United States Metallic Packing 
 
 Co., 56, 204. 
 
 University College, London, 177. 
 University of Liege, 62. 
 Unwin, Prof., 37, 76, 134, 199. 
 Use of steam, 84. 
 
 Value of steam-jacket, 103, 175. 
 Vertical boilers, 43. 
 Vertical engines, 37, 43, 76. 
 Vivian, 9, 98. 
 
 Wasteful engines, 31, 38, 54. 
 Water-jackets, 58, 59, 119, 120, 
 
 149, 150, 186. 
 
 Water in cylinder covers, 129. 
 Water-tube boilers, 42, 43. 
 Watt's cylinder, 21 ; first jacket, 
 
 5. 
 Watt's invention, 1, 3 ; later 
 
 jackets, 5, 7 ; patent, 3. 
 Watt's practice, 71 ; trials, 153. 
 Well-arranged jackets, 87. 
 Wet steam, 49, 75, 109, 203. 
 Whitworth liners, 126. 
 Whyte & Cooper's condenser, 
 
 205. 
 
 Winterthur, 28, 84. 
 Wolverhampton trials, 71. 
 Woolf, 9 ; beam engine, 171, 172. 
 Woolf diagram, 79. 
 Work condensation, 49, 53, 73. 
 Wylam Railway, 10. 
 
 Yorkshire College, 83. 
 
218 
 
 ADVERTISEMENTS 
 
 HOPKINSON'S 
 
 IMPROVED SJEAM ENGINE 
 
 INDICATORS. 
 
 Complete in Lock-up Mahogany Case, with 4 Springs 
 and Scales. 
 
 Price 7, Os. Od. 
 
 Catalogue of Hopkinson's Patent Specialities. 100 Pages. 
 Post Free. 
 
 J. HOfTOSOfl & CO., Limited, 
 
 BRITANNIA WORKS, HUDDERSFIELD. 
 
DIRECTORY OF MANUFACTURERS OF 
 FUEL-SAVING APPLIANCES, &c. 
 
 PAGE 
 
 Automatic Expansion Gear (Proell's patent). H. Kiihne, . . 220 
 
 Economises. E. Green & Sons (facing title-page). 
 
 Evaporative Condensers. Whyte & Cooper, .... 221 
 
 ,, ,, Meldrum Brothers (facing front cover}. 
 
 Exhaust Injectors. Patent Exhaust Injector Co., . . . 222 
 Feed Water Filters. Copley, Turner, & Co., . . . .224 
 
 Feed Water Heaters. T. Shore & Sons, 230 
 
 Forced Draught. W. Granger (facing end matter), . . . 211 
 
 ,, Meldrum Brothers (facing front cover). 
 
 Indicators. J. Hopkinson & Sons (facing Directory), . .218 
 Metallic Packing. The United States Metallic Packing Co., . 223 
 Patent Safety Boiler Mountings. J. Hopkinson & Sons (facing 
 
 Directory), .218 
 
 Phosphor Bronze. The Phosphor Bronze Co. (inside end cover). 
 ,, Bull's Metal Phosphor Bronze Co. (facing 
 
 end cover). 
 Pistons. Lancaster & Tonge (inside front cover). 
 
 Return Steam Traps. W. Dawson & Co 225 
 
 Steam Engines. H. Bollinckx, 226 
 
 Steam Fittings. Llewellin & James 228 
 
 Steam Separators. J. Royle, 227 
 
 Steam Traps. Lancaster & Tonge (inside front cover). 
 
 J. Royle, 227 
 
 Llewellin & James, ,228 
 
 W. Dawson & Co., 225 
 
 Superheaters. MThail & Simpson, 229 
 
 Messrs Whittaker's Books (facing half-title), . . . .231 
 Steam Locomotion on C 
 Steam Jacket Reviews, 
 
 Steam Locomotion on Common Roads, } TWO pages before half- 
 
 . / 
 
220 
 
 ADVERTISEMENTS 
 
 Proell's Patent Automatic Expansion Apparatus, 
 
 A self-contained 
 combination of a 
 perfect Governor and 
 the most reliable 
 Expansion Gear, 
 
 Easily applied to 
 
 existing Slide Valve 
 
 Engines, 
 
 Special Forms made for 
 
 NEWLY BUILT 
 ENGINES, 
 
 which are thereby made 
 
 equal in regularity of 
 
 speed and economy of 
 
 steam to the best 
 
 Corliss Engines, 
 
 For full Particulars apply to 
 
 HERMANN KUHNE. 
 
 GENERAL AGENT FOB 
 ENGLAND TOR 
 
 Dr. Proell's Patents, 
 
 Contractor to the War Office, 
 and to the India Office. 
 
 25-35 NEW BROAD 
 STREET, 
 
 LONDON, E.C. 
 
 Indicator Diagrams from Slide Value Engine, 
 with Proell's Patent Expansion Apparatus. 
 
ADVERTISEMENTS 
 
 221 
 
 PATENT 
 EVAPORATIVE CONDENSERS, 
 
 More efficient than any other system of Condensation. 
 
 SO per cent, saving in Steam against H.-P. working. 
 
 47 .. Water per I. H.-P. 
 
 80 ii more work from same set of Boilers. 
 
 J. * H. WHYTE & COOPER, 
 
 BRITANNIA ENGINE WORKS, 
 DUNDEE, N.B. fr 
 
 MILL ENGINES 
 and BOILERS of 
 every description. 
 
 Lancashire, 
 Cornish, 
 Marine, 
 Upright, 
 Locomotive. 
 
 Patent 
 
 Automatic Valve 
 
 Motion fitted to 
 
 existing Engines. 
 
 Hydraulic Lifts, 
 Hydraulic Presses, 
 Tanks, 
 Cranes. 
 
222 ADVERTISEMENTS 
 
 THE PATENT 
 
 Exhaust Steam Injector Company, Ltd,, 
 
 ENGINEERS, 
 
 4 ST. ANN'S SQUARE, MANCHESTER. 
 
 TELEGRAMS: "EXHAUST," MANCHESTER. 
 
 Sole Manufacturers of 
 
 jgybauet Steam 3njector0. 
 
 To work against all Pressures. 
 
 (DAVIES & METCALFE'S PATENT.) 
 At a moderate Estimate these Injectors have saved 
 
 3,000,000 TONS OF COAL 
 
 during the last fourteen years, in England alone. 
 
 USERS SAY 
 
 ' ' The average consumption of coal was four tons a week, it is now 
 reduced to three tons." 
 
 ' It has effected a saving of coal of about 30 per cent." 
 ' It is seldom I have found statements with regard to economy so 
 fully borne out as yours have been." 
 
 ' We find it saves about 25 per cent, of water." 
 ' We have had no trouble with it, nor any expense. " 
 ' We have been able to take off one boiler, though the engines 
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 "The repairs to our boilers since the Exhaust Injector has been 
 used, have not been more than half the cost they were before. " 
 
 "The Exhaust Injector has saved its cost in the three months it 
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 Sole Manufacturers of 
 
 Gbe automatic IRe^etarting Injector. 
 
 The best live Steam Injector for all purposes. 
 
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 of Injectors, Messrs Sharp, Stewart, & Co., Limited, 
 
 and Makers of Giffard, Atlas, Friedmann, Webb, 
 
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 4 ST. ANN'S SQUARE, MANCHESTER. 
 
A D VERTISEMENTS 
 
 223 
 
 TWO GOOD THINGS. 
 
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 METALLIC PACKING. 
 
 Over 6O 5 OOO Packings now 
 in use, 
 
 THE PACKING OF THE FUTURE. 
 
 Simple, Reliable, Durable, 
 Economical. 
 
 SPEEDY. 
 DURABLE. 
 
 Fitted on 
 H.M.S. 'Jupiter,' 
 H.M.S.' Terrible,' 
 H.M.S. ' Sultan,' 
 H.M.S. 
 ' Hermione,' 
 H.M.S. 
 'Rocket,' 
 ' Paris,' 
 'York,' 
 
 WILL 
 DO THE 
 WOBK OF 
 1C MEN 
 WITH 
 RATCHET 
 
 WEIGHT 35 TO 50 LBS. 
 
 BRADFORD PORTABLE POWER DRILL 
 
 OPERATED BY STEAM OR AIR PRESSURE. 
 
 Inualuable for Bridge and Boiler Work, Repairs, &c, 
 
224 
 
 ADVERTISEMENTS 
 
 TELEGRAMS: "WINDTIGHT," LONDON. 
 TELEGRAMS TO WORKS: "VULCAN," MIDDLESBROUGH. 
 
 Sole Makers for United Kingdom of the 
 
 " Harris Patent Feed-Water Filter." 
 
 Copley, Turner & Co., 
 
 LIMITED, 
 73 QUEEN VICTORIA ST., 
 
 LONDON, E.C, 
 
 JH HHS 
 
 
 Supplied to the 
 
 English Admiralty, 
 Indian Government, 
 Russian Navy, 
 Cunard Co., 
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 and every Steam Ship 
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 Numerous Land Engines 
 and Electric Installa- 
 tions. 
 
AD VERTISEMENTS 225 
 
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 Heating and Mechanical Engineers, 
 
 HARTLEY WORKS, STALYBRIDGE, 
 Near MANCHESTER. 
 
 Also at LONDON, MANCHESTER, GLASGOW, and BELFAST. 
 
 Telegraph Address: " DAW SONS," STALYBRIDGE. 
 NATIONAL TELEPHONE, 84. 
 
 SOLE MANUFACTURERS OF 
 
 KIELEY'S PATENT 
 
 RETURN STEAM TRAP, 
 
 For returning to the Boilers the Water of Condension from Jacketed Cylinders 
 of Steam Engines. Also from Steam Heating or Drying Pipes, Drying Cylinders, 
 'iVntering and Slashing Machines, Wool Dryers, Brewer's Boiling and other 
 Pans, or wherever Steam is condensed under Pressure whether ABOVE or BELOW 
 the Boilers. 
 
 The RECEIVER shown below illustrates 
 the .Return Pipes entering same and the 
 Connecting Pipe between Receiver anil 
 the Steam Trap. 
 
 N.B. This Trap is patented in the 
 United Kingdom, America, and the Con- 
 tinent of E^lrope. 
 
 The amount to be saved by utilising the waste water of Condensation (usually wasted 
 is much more than is generally supposed by those who have not experienced the returning 
 of same to the Boilers, and where Boilers are very much pressed their capacity is greatly 
 increased and maintained in a much better state of preservation. 
 
 PLANS, SPECIFICATIONS, and ESTIMATES on APPLICATION, with or 
 without Fittings, and inclusive or exclusive of fixing the same. 
 
 P 
 
226 
 
 ADVERTISEMENTS 
 
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 H. BOLLINCKX 
 
 (SOCIETE ANONYMB). 
 
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 TRANSMISSIONS. 
 
 95 CHAUSSEE DE MONS, 
 
 BRUXELLES. 
 
A D VEKTISEMENTS 
 
 227 
 
 ROYLE'S PATENTS. 
 
 
 
 STEAM DRYERS. 
 
 FOR AUTOMATICALLY INTERCEPTING 
 
 And discharging water of condensation in Steam Pipes. 
 Saving damage to Engine from water in Cylinder. 
 Saves breakage of Joints in Pipes. Saves Coals by 
 permitting only dry Steam to enter Cylinder. 
 
 No range of Steam Pipes is safe without it. 
 
 For long ranges it is invaluable. 
 
 Intercepting the water should be the first care, and a 
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 performs both. 
 
 All Sizes from 1 in, up to 12 in, 
 
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 SIMPLE. No inaccessible parts. 
 
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 SPECIAL FEATUJRE is the 
 Syphon H, which ensures per- 
 fect trapping. 
 
 30,000 IN USE. 
 
 The Valve E is the only wearing 
 
 THE BEST TRAP for dirty water. 
 
 part, and can be cheaply renewed. Supplied on approval. 
 
 Prices- 
 
 n 
 
 17 6 
 
 JC2 15 
 
 10 
 
 4 5 
 
 6 10 
 
 12 
 
 All Sizes in Stock ready for delivery. 
 
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 131 GREAT BRIDGEWATER STREET. 
 
228 
 
 A D VERTISEMENTS 
 
 LLEWELLIJ4S & JAMES, 
 
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 SOLE MAKERS OF 
 
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 THE MOST SIMPLE IN EXISTENCE. 
 
 ALSO SOLE MAKERS OF 
 L. & J.'s PATENT ASBESTOS-PACKED 
 
 GUN METAL STEAM FITTINGS. 
 
 
 
ADVERTISEMENTS 229 
 
 MTHAIL & SIMPSONS' 
 PATENTS. 
 
 STEflM GENERATOR AflD 
 SUPERHEATER. 
 
 Greatest Reduction in Cost of Steam Production 
 
 of the Age. 
 
 Guarantee of Economy given in all cases. 
 Important to all Steam Users. 
 
 Applicable to all Steam Boilers, Land or Marine. 
 Produces a large saving of Fuel, greater carrying capacity 
 in Steam Ships. Prevents priming and Cylinder Condensa- 
 tion. Perfect control of amount of Superheat and 
 Temperature of Steam. No injury to Cylinders, Valves, 
 Pistons, or difficulty in Lubrication. Durability. Thorough 
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 three years working in large number of both Old and New 
 Boilers. All parts subject to Pressure. Tested to 500 Ibs. 
 per square inch. 
 
 Passed by Lloyd's Committee and the Boiler 
 Insurance Companies. 
 
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 References and Tests of Economy on application. 
 
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230 
 
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AD VERTISEMENTS 231 
 
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 ON THE CONVERSION OF HEAT INTO WORK. A Practical Handbook 
 
 on Heat-Engines. By WILLIAM ANDERSON, F.R.S., D.C.L., Member of the Council of 
 the Institution of Civil Engineers, M.I.M.E., and Director-General of Ordnance Factories, 
 Royal Arsenal, Woolwich. With 62 Illustrations. 
 " We have no hesitation in saying there are young engineers and a good many old engineers 
 
 top who can read this book, not only with profit, but pleasure, and this is more than can be 
 
 said of most works on heat." The Engineer. 
 
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 87 SUMNER STREET, SOUTHWARK, 
 
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