the triple expansion marine engine; both of these use steam pressures, seldom less than 165 pounds per square inch. In locomotive design the present proportions are the outcome of a practical acquaintance with the success or failure of each and every detail, covering experiences in thousands of locomotives with every peculiarity of design, operating on road-beds of every conceivable variety, often under conditions that would seem to invite failure, and through it all the locomotive stands the test with an economic margin that invites confidence and places upon its design and proportions the seal of approval. Similarly the success of the modern triple expansion marine steam-engine, the designs for which are based upon accurate knowledge of the strength and elasticity of materials employed, to which is added an increment in size, based upon experience, to resist stresses occurring at irregular intervals with a suddenness that would seem to imperil the safety of the engine; the proportioning of parts that will completely absorb such shocks without harm and without stoppage in service, is one of the results of thorough technical training supplemented by experiences which can only be had at sea. There has been no attempt-in fact, the writer disavows any intention of making this a text-book in engineering. The designs illustrated and accompanied by tables of working dimensions are based mainly upon marine and railroad practice, than which no severer working tests occur; the proportions given have long since passed the experimental stage and are known to be ample for the controlling unit, in any given case. Machine design in its narrowest applications is all that is attempted in this work; it has been his opinion throughout that the theory of machines, applied kinematics or machines considered as modifying motion, applied dynamics or machines considered as modifying both motion and force, are subjects requiring special mathematical treatment, and therefore foreign to the present purpose: he contents himself with the simple presentation of some acceptable details in machine construction. The writer is under obligations to many professional friends contributing and assisting in the selection of material for these pages. His thanks are especially due officials of the Navy Department, the Bureau of Mines, the Bureau of Standards, Examiners in several of the Departments in the U. S. Patent Office; for courtesies in the Library of Congress, the Smithsonian Institution, etc. Extended use has been made of official reports on materials forming the basis of engineering specifications now used in Government contracts, especially those relating to the Navy. Free use has also been made of the Records of Tests made at the Watertown Arsenal, the Washington Navy Yard, and other Governmental Laboratories. In this connection it will be understood that the official reports and specifications appearing in this book are for the information of the reader, and not herein officially published. As to the apparent exclusion of excellent work done by several Societies in Testing Materials, as well as to results of tests made public by railroads, steel works, forges, foundries, and other industrial plants, it occurs only through lack of space; preference is given the Government Specifications based upon extended chemical and physical investigations because, as presented, they are more or less mandatory in their application. Free use has been made of valuable contributions to the various engineering societies, magazines, and trade papers covering almost every department of technology. The writer's collection of such material is large, and as most of the papers have been prepared by experts their value is correspondingly great; the collection thus serves to supplement some of the more recent books authoritatively. With the development of the subjects selected for this book it has become necessary to divide the work into two parts. The present volume, Part I, deals mostly with the chemical and physical properties of the materials used in engineering, particularly such as are called for in Government specifications; these specifications are so numerous and conform so minutely to the official terms, that the space occupied by them is more than double that originally assigned. This has been the case in other sections as well, but the expansion of the work is believed to be wholly in the interest of and will prove doubly useful to, the reader. Part II is in active preparation for early publication. The long delay after the preliminary announcement regarding its preparation for early publication has been due to the industrial changes which have taken place through out our country because of the European War, an occurrence which has made necessary many changes in the book, including the rearrangement and rewriting of whole sections, the preparation of new drawings, the calculating of new tables, all of which has taken much time, but it has greatly increased the value and importance of the book. Complete accuracy is not expected in a work involving so much detail as does this, and the writer can only say with respect to this detail that the present work represents an extended and thoroughly earnest effort on his part to secure perfectly reliable material, arranging it in convenient sequence, presenting it in clearly printed pages and carefully indexing the whole for ready reference. WILLIAM M. BARR. NEW YORK, September, 1918. CONTENTS Unit of Time Standard of Length-Unit of Mass-C. G. S. System-Me- chanical and Geometrical Quantities-Units of Measurement and De- rived Units in use in Great Britain and the United States-Fundamental and Derived Units of Length, Mass, Time, and Temperature-Geometric and Dynamic Units-Air as a Standard-Water as a Standard-Physical Constants of Metals-Melting Points of Chemical Elements-Specific Gravity of Metals, Minerals, and other substances-Horsepower- Kilowatt as a Unit of Power-Table of Horsepowers to Kilowatts-Table Measures of Length-Measures of Surface-Measures of Volume-Measures of Capacity-Avoirdupois Weight-Troy Weight-Apothecaries' Weights and Measures-United States Money-Value of Foreign Coins in United States Money-Measures of Time-Longitude and Time Compared- Metric System of Weights and Measures-Tables for Interconversion of Metric and United States Weights and Measures-Table of Admiralty Knots to Statute Miles and Kilometers-Tables: Pounds per Square Inch to Kilograms per Square Centimeter; Cubic Feet Per Second to Cubic Meters per Second. Tables: Wire Gauges in use in the United States- United States Standard Gauge for Sheet and Plate Iron and Steel-Legal MENSURATION AND MECHANICAL TABLES Mensuration of Surfaces-Table of Useful Functions of Pi (7)—Tables: Diame ter, Circumference, Area of Circles, and Side of Equal Square Diameters and Areas of Circles, with Squares, Cubes, Square and Cube Roots- Reciprocals of Numbers-Lengths of Circular Arcs-Areas of Circular Segments-Area of an Irregular Figure-Plane Trigonometry-Trigono- metrical Formula-Sines, Cosines, Tangents, Cotangents, Secants, and Cosecants of Angles 0° to 90°-Logarithmic Sines, Cosines, Tangents, and Cotangents of Angles from 0° to 90°. Mensuration of Solids-Logarithms Amalgams-Ammonia-Antimony - Arsenic Asbestos Austenite ·Ferrite- - Gold - - Open-Hearth Steel, Acid and Basic-Talbot Process-Oxides-Oxygen- ite-Zinc. - Alloy Steels: Simple Tungsten Steel-Simple Chromium Steel-Maganese Steel-Simple Nickel Steels-Properties of Ordinary Nickel Steel- Nickel-Chromium Steels-Mayari Steel-Silicon Steels-High-Speed Tool Steels-Stellite Chromium-Vanadium Steels-Heat Treatment of Alloy Steels-Heat Treatment of High Speed Tools-Theory of High Navy Department Requirements for Steel Plates, Shapes, and Bars-Rivet Fire Clays and Fire Bricks: Nature of Refractory Clays-Effect of the Acces- sory Constituents of Fire Clays upon the Softening Temperatures, such as Quartz, Alumina, Iron Oxide, Feldspar, Mica, Lime-Effect of Fluxes upon Refractoriness-Load Tests of Fire Brick-Effect of Chemical Composition-Fire Brick and Clay Analysis-Chemical Formulæ— Results of Physical Tests at 1,300° C, and with a load of 75 pounds per square inch-Influence of Cold-Crushing Strength. Structural Timbers Used in Engineering: Southern Yellow Pines: Longleaf Pine, Shortleaf Pine, Loblolly Pine-Timbers of the Pacific Coast: Doug- las Fir, Western Hemlock, Western Larch, Redwood-Timbers of the STEEL BARS, PLATES, SHAPES, BOLTS, RIVETS Requirements for Navy Department: Physical and Chemical Properties of |