Transcriber’s Notes Text printed in italics in the original work are represented between underscores as in _text_. Small capitals have been transcribed as ALL CAPITALS. ^{text} represents a superscript text, _{text} respresents a subscript text. More Transcriber’s Notes may be found at the end of this text. INVENTORS AT WORK [Illustration: Copyright by Park & Co., Brantford, Ontario. PROFESSOR ALEXANDER GRAHAM BELL.] Inventors at Work With Chapters on Discovery By George Iles Author of “Flame, Electricity and the Camera” Copiously Illustrated [Illustration] New York Doubleday, Page & Company 1907 Copyright, 1906, by GEORGE ILES _Published October, 1906_ All rights reserved, including that of translation into foreign languages, including the Scandinavian TO MY FRIEND JOSEPHUS NELSON LARNED OF BUFFALO, NEW YORK CONTENTS PAGE LIST OF ILLUSTRATIONS xiii ACKNOWLEDGMENTS xxi CHAPTER I. INTRODUCTORY 1 II. FORM Form as important as substance. Why a joist is stiffer than a plank. The girder is developed from a joist. Railroad rails are girders of great efficiency as designed and tested by Mr. P. H. Dudley 5 III. FORM CONTINUED. BRIDGES Roofs and small bridges may be built much alike. The queen-post truss, adapted for bridges in the sixteenth century, neglected for two hundred years and more. A truss replaces the Victoria Tubular Bridge. Cantilever spans at Niagara and Quebec. Suspension bridges at New York. The bowstring design is an arch disguised. Why bridges are built with a slight upward curve. How bridges are fastened together in America and in England 18 IV. FORM CONTINUED. LIGHTNESS, EASE IN MOTION Why supports are made hollow. Advantages of the arch in buildings, bridges and dams. Tubes in manifold new services. Wheels more important than ever. Angles give way to curves 39 V. FORM CONTINUED. SHIPS Ships have their resistances separately studied. This leads to improvements of form either for speed or for carrying capacity. Experiments with models in basins. The Viking ship, a thousand years old, of admirable design. Clipper ships and modern steamers. Judgment in design 52 VI. FORM CONTINUED. RESISTANCE LESSENED Shapes to lessen resistance to motion. Shot formed to move swiftly through the air. Railroad trains and automobiles of somewhat similar shape. Toothed wheels, conveyors, propellers and turbines all so curved as to move with utmost freedom 65 VII. FORM CONTINUED. ECONOMY OF LIGHT AND HEAT