Sheffield Scientific School, Yale University, October, 1915. AUTHOR’S NOTE In reprinting this book certain minor corrections have been made. In the later chapters references occur here and there to the “present” condition of various plants and firms. After careful consideration, it seems wise to let these statements stand as they were written in 1915. Interest in this subject centers chiefly on the early history of the plants and firms rather than on recent changes. To revise the statements, bringing them up to date, would add little. With the ever shifting status of a live industry, the statements, so revised, would remain correct for only a short time. Therefore, when a reference is made to present conditions it should be understood to cover those at the beginning of the World War, which is a natural dividing point in our industrial history. The general predictions made in the last two paragraphs of the book have been borne out by the developments in American toolbuilding since that time. Museum of the Peaceful Arts, City of New York, February, 1926. TABLE OF CONTENTS PAGE Chapter I. Influence of the Early Tool Builders 1 Chapter II. Wilkinson and Bramah 11 Chapter III. Bentham and Brunel 22 Chapter IV. Henry Maudslay 33 Chapter V. Inventors of the Planer 50 Chapter VI. Gearing and Millwork 63 Chapter VII. Fairbairn and Bodmer 71 Chapter VIII. James Nasmyth 81 Chapter IX. Whitworth 98 Chapter X. Early American Mechanics 109 Chapter XI. The Rise of Interchangeable Manufacture 128 Chapter XII. Whitney and North 145 Chapter XIII. The Colt Armory 164 Chapter XIV. The Colt Workman--Pratt & Whitney 173 Chapter XV. Robbins & Lawrence 186 Chapter XVI. The Brown & Sharpe Manufacturing Company 202 Chapter XVII. Central New England 216 Chapter XVIII. The Naugatuck Valley 231 Chapter XIX. Philadelphia 239 Chapter XX. The Western Tool Builders 261 Appendix A 281 Appendix B, The Jennings Gun 292 A Partial Bibliography on Tool Building 295 LIST OF ILLUSTRATIONS Henry Maudslay _Frontispiece_