ENGINEERING MAGAZINE, COMMENCED JANUARY, 1869, Published on the 15th of the month at $5.00 per year. The January number of this MAGAZINE, for the year year 1881, begins the Twenty-fourth Volume. Beginning as an Eclectic Journal, and presenting almost exclusively matter selected from current literature, it has gradually become the chief medium through which the leading writers on engineering subjects can best present their original essays to American readers. The attitude of the MAGAZINE has been, and will continue to be, that of a journal of original and selected papers upon subjects relating to modern advanced Engineering. Theoretical and Practical Essays are alike presented in its pages, although the latter largely out-number the former, as best suited to the tastes and demands of the American Engineers. Some of the most valuable contributions to the literature of technical science within the last few years have been first presented in these pages. Among the more extended original contributions to the later volumes may be cited new contributions to Graphical Statics-Transmission of Power by Wire Ropes-Maximum Stresses in Framed Bridges-Momentum and Vis Viva-Rapid Methods of Laying out Gearing-Transmission of Power by Compressed Air-Geographica. SurveyingMathematical Theory of Fluid Motion - Thermodynamics - Practical Theory of Voussoir Arches-Cable Making for Suspension Bridges, &c., &c. To the above may be added the following valuable essays, translated from foreign sources, which have first appeared in these pages: Linkages and their ApplicationsThe Origin of Metallurgy-and The Theory of Ice Machines. The plans for future volumes comprehend many improvements in the same direction. The wants of the educated practical engineer, who desires to keep in the foremost rank of his profession will be steadily kept in view, and our constantly increasing resources for supplying the best of scientific information will be employed to secure such result. Cloth covers for Volumes I. to XXIII. inclusive, elegantly stamped in gilt, will be furnished by the publisher, for fifty cents each. If the back numbers be sent, the volumes will be bound neatly in black cloth and lettered, for seventy-five cents each. The expense of carriage must be borne by the subscriber. Notice to New Subscribers.-Persons commencing their subscriptions with the Twenty-fourth Volume (January, 1881), and who are desirous of possessing the work from its com. mencement, will be supplied with Volumes I. to XXIII. inclusive, neatly bound in cloth, for $60.00, in half morocco, $90.00. Notice to Clubs.-An extra copy will be supplied gratis to every Club of Five subscribers at $5.00 each, sent in one remittance. SMALL MOTIVE POWER. By Henry S. H. Shaw, Stud. Inst. THE FLOW OF GASES THROUGH TUBES. By Prof. S. W. PAGE. From Selected Papers Inst. Civil Eng... 353 .. Contrib. to Van Nostrand's Magazine.. 370 PRACTICAL FORMULAS FOR ANGLE BLOCKS AND BRACES OF ON THE ACTION OF COKE SLAG ON FIREPROOF MATERIALS. .Proceedings of Royal Society.. .From Abstracts of Inst. Civil Eng.... ON THE DISCHARGE OF WATER THROUGH SLUICES AND AN INSTRUMENT FOR THE DETERMINATION OF LATITUDE. 379 383 .Foreign Abstracts of Inst. Civil Eng... 385 .From Proceedings of Society of Arts.... 387 THE BEHAVIOR OF RAILWAY CARRIAGES IN PASSING .Foreign Abstracts Inst. Civil Eng..... 390 395 ON THE CONSTRUCTION, PERFORMANCE, AND WORKING OF THE INJECTOR AS A MOTOR FOR HYDRAULIC LIFTS. By Hr. .From Abstracts Inst. Cicil Eng... 398 From Abstracts Inst. Civil Eng.... 400 DEEP-SEA INVESTIGATION, AND THE APPARATUS EMPLOYED THE GASKILL COMPOUND PUMPING ENGINE. By John W. STREET CLEANSING IN PARIS. By M. Vaissiere.. .From Papers of the Royal Eng. Inst... 427 428 .Foreign Abstracts Inst. Civil Eng...... 431 PARAGRAPHS.-The Society of Civil Engineers of Paris and French Ports, 378; Ceara Rubber, 384; Tin Plates,397; A Pulverizing Lubricant, 430. REPORTS OF ENGINEERING SOCIETIES.-American Society of Civil Engineers; Polytechnic Association of the American Institute, 433; Engineer's Club of Philadelphia, 434. ENGINEERING NOTES.-The Arlberg Tunnel, 434; The Panama Canal, 435. RAILWAY NOTES.-The First Rack Railway in Prussia, 435. ORDNANCE AND NAVAL.-The New Armored Cruiser, 435; New Steam Pinnace, 436. BOOK NOTICES.-Publications Received; Notes on Rankine's Applied Mechanics, by George I. Alden, B.S.; Electrotyping-A Practical Manual, by J. W. Urquhart, C.E., 436; Measures, Weights and Moneys of All Nations, by W. S. B.Woolhouse, F.R.A.S.; The Gas Engineer's Diary and Text Book for 1881, by G. E. Wright and Wm. S. Mason: River Bars, their Formation and Treatment, by I. J. Mann; The Coal Fields of Great Britain, by Edward Hull, LL.D., F.R.S.; Mine Drainage, by Stephen Michell; A Technical Treatise on Soap and Candles, with a Glance at the Industry of Fats and Oils, by R. S. Cristiani; Imaginary Quantities, by Prof. A. S. Hardy: Synopsis of the Free-Water Rhizopods, compiled by Romyn Hitchcock, F.R. M.S.; Electric Lighting, by Wm. Edward Sawyer. 437; Shock's Steam Boilers, 438. MISCELLANEOUS.-Geographical Notes, 439; Sanitary Houses, 440. VAN NOSTRAND'S ENGINEERING MAGAZINE. NO. CXLIX.-MAY, 1881.-VOL. XXIV. SMALL MOTIVE POWER. By HENRY S. H. SHAW, Stud. Inst. C.E. From Selected Papers of the Institution of Civil Engineers. AIR. II. the fluid was so great as to give a reAfter some long and thorough trials sultant efficiency superior to that of alon a large scale of hot-air engines, the most all steam engines at the time of most important of which were at the the experiments referred to." In spite Dundee Foundry, about 1845,* and on of these facts, it was not till a few years the ship Ericsson, 1852, hot air has been ago that small hot-air engines had any universally acknowledged to be adapted considerable use in this country. The only to perform operations requiring but reason for this has been already referred little power, its present application in to the high temperatures required, and this country being almost entirely con- the latter rendering bulky apparatus the narrow range of effective pressure; fined to the immediate supersession of hand labor. The hot-air engine has, necessary to produce much power, the however, a high efficiency, and in the former rendering the mechanical difficulfirst of the above cases, Mr. J. Stirling, ties in dealing with that apparatus very the son of the original inventor, stated great, as, for instance, the permeation of that the Stirling engine, then described, the glowing fire box by the air under used only 2 pounds of coal per hour compression, which it has been proved takes place. Now, however, there are per HP., which was said to be of that used by the best steam engines of the several successful patents for hot-air enday; and in the discussion which fol- gines whose great recommendation is lowed, the author stated that he had the absolute freedom from danger of "every reasonable confidence in its ulti-explosion, and almost noiseless action, mate success." Again, in the second case together with a high efficiency. There in which Ericsson's engine was used, the are two kinds of engines which, accordaction of which is described by Professoring to the method of using the working Rankine,† the consumption of anthracite fluid, are called was 1.87 pound per hour per HP., where, "notwithstanding the low efficiency of the efficiency of the furnace, . "closed" 66 or open. The two engines above mentioned are prototypes of these two classes. In the Stirling engine the same mass of air under pressure was used continuously, and by alternate heating and cooling was made to do work; it is therefore called "closed." In the Ericsson engine a fresh supply of air was taken in by the and, being horizontal, considerable space engine at every stroke, in a similar way is necessary. While the machinery of to steam from a boiler, and after doing Lehmann's is decidedly complicated, Lauwork by the application of heat, was re- bereau's is vertical, and very compact jected in a similar way to steam; it is and portable, and, in spite of the altherefore called "open." With regard leged defect pointed out by Dr. Slaby, to the latter, little will be said; for as which is avoided in Lehmann's engine, far as the author is able to learn, they viz., that the heating chamber communiare scarcely if at all used in this country. cates directly with the working piston, In Germany the open engine of Hock, and so renders the packing liable to and in France that of Belou, give satis- rapid deterioration, it has worked satisfactory results, but these differ in an im-factorily, using, in a trial quoted by Mr. portant point from the Ericsson engine, D. K. Clark, 4.8 pounds of coal per hour the air not being heated by mere con- per HP., and 11 pounds per HP. at the tact with a metallic surface, but being brake. Lehmann's engine has been remade to pass through the fire and sup- cently introduced into this country, and port combustion, thus bearing a resem- was awarded the first prize at the Manblance to the action of gas engines. In chester and Liverpool Show, 1879; but a trial of the Belou engine at Cusset, at present the engine most generally quoted by Mr. D. K. Clark (p. 918, "Rules and Tables"), the consumption of coal was 0.735 pounds per hour per I.HP., and 3.24 pounds per net HP. at the brake. In a trial of a Hock engine by Professor Jenny, of the Imperial Technological School of Vienna,* 7 kilogrammes of coke were used in sixtythree minutes by an engine developing 1.58 HP. at the brake, which is almost exactly equivalent to 9 pounds of coke per hour per HP. These results compare favorably with the work done by most closed air engines, but the Belou engine was of large size-of more than 27 HP.; and it is the Hock engine, or one similar to it, which is of low first cost, and has many advantages, that must be regarded as the one whose introduction might profitably take place, and which is spoken very highly of in the report referred to. Closed air engines are numerous; those of Laubereau, Lehmann, Stenberg (the Calorisca), D. van Rennes, and Rider being the principal. With each there is some difference in theory, as shown by Dr. A. Slaby.† A distinction can, however, be made between single and double-acting engines. Laubereau's, which is a modification of Stirling's, is commonly used in France; while in Germany Lehmann's is most popular, as testified by the fact that over a thousand are there in use. Both Lehmann's and Stenberg's have a brickwork erection at the end distant from the crank shaft, *Klein-Kraft-Maschinen," p. 42. + Vide Minutes of Proceedings Inst. C. E., vol., p. 370. Fig. 11. used is that of Rider, of which, since its introduction from America three years ago, upwards of nine hundred have been sold; therefore, of this only will a description be given. Fig. 11 is a sectional view taken from the prospectus of the company; it is there seen to be singleacting, and to consist of two cylinders, A and B, in which two vertical hollow |