The present edition has been revised throughout, and such changes have been made as were required to bring the matter into accordance with the progress that has taken place since this book was first published in 1876. But details given in the former editions have at the same time been retained where they served to indicate the successive stages of improvement. It would, for example, be impossible in a section on steam navigation, to omit some notice of the _Great Eastern_, and therefore the drawings and the account of the construction of that remarkable ship that appeared in the first edition, have been left with but slight alterations in the present volume, although the vessel has since been broken up. On the other hand, two sections are devoted to projects which the XIXth century has not seen realised; but the XXth century will in all probability shortly witness the completion of one or other of the great canal schemes; and if the first submarine tunnel is destined not to be one connecting England with the Continent, it will be one uniting Great Britain with her sister isle. 1899. * * * * * For permission to make use of illustrations in this volume the author’s and publishers’ thanks are due to the several proprietors of _The Graphic_ (for Plates I., XI., and XII.)—of _The Engineer_ (for sketch design of the Great Wheel, map and views of the Tower Bridge)—of _The Scientific American_ (map of North Sea Canal); also to Mr. Walter B. Basset (for Plate V.)—to “The Cassier Magazine Company” (for Edison’s Kinetographic Theatre and the Hotchkiss Gun)—to “The Century Company” (for portrait of M. Tesla, from a photograph by Sarony)—to “The Incandescent Gas Light Company” (for cuts of burners, etc.)—to _The Engineering Magazine_, and _The Engineering News_, both of New York—to the Remington Company—to Mr. W. W. Greener, of Birmingham (for cuts of rifles, etc., from his comprehensive book on “The Gun”)—to _The Photogram_, Limited—to the Proprietors of _Nature_—to the Linotype Company—and to Captains Hadcock and Lloyd (for illustrations of modern artillery from their great work on the subject). CONTENTS. PAGE INTRODUCTION 1 STEAM ENGINES 3 THE LOCOMOTIVE 14 PORTABLE ENGINES 24 THE STEAM HAMMER 25 IRON 29 IRON IN ARCHITECTURE 72 BIG WHEELS 81