Note: Project Gutenberg also has an HTML version of this file which includes the original illustrations. See 42602-h.htm or 42602-h.zip: (http://www.gutenberg.org/files/42602/42602-h/42602-h.htm) or (http://www.gutenberg.org/files/42602/42602-h.zip) Some characters might not display in this UTF-8 text version or in the html version. If so, the reader should consult the iso-8859-1 (Latin-1) text file 42602-8.txt or 42602.zip: (http://www.gutenberg.org/files/42602/42602-8.txt) or (http://www.gutenberg.org/files/42602/42602-8.zip) Images of the original pages are available through Internet Archive. See https://archive.org/details/steamengineexpla00lardrich Transcriber's note: Text enclosed by underscores is in italics (_italics_). The notation "^{n}" means that n is superscript. The notation "_{n}" means that n is subscript. Text that was in small capitals has been converted to all capitals. The original page numbers are embedded in square brackets, e.g. "[Pg135]". More detailed notes are provided in the Transcriber's endnote. [Illustration: WATT. Engraved by H. Adlard, from a Drawing by H. Corbould, taken with the permission of James Watt, Esq. FROM THE STATUE BY CHANTREY. London: Taylor & Walton, Upper Gower Street.] THE STEAM ENGINE EXPLAINED AND ILLUSTRATED; With an Account of Its Invention and Progressive Improvement, and Its Application to Navigation and Railways; Including also a Memoir of Watt. by DIONYSIUS LARDNER, D.C.L. F.R.S. &c. &c. SEVENTH EDITION, Illustrated by Engravings on Wood. London: Printed for Taylor and Walton, 28. Upper Gower Street. MDCCCXL. London: Printed by A. Spottiswoode, New-Street-Square. TO THE RIGHT HONOURABLE HENRY LORD BROUGHAM AND VAUX, FELLOW OF THE ROYAL SOCIETY, AND MEMBER OF THE NATIONAL INSTITUTE OF FRANCE, AS A MARK OF PUBLIC RESPECT AND A TESTIMONY OF PRIVATE REGARD, THIS WORK INSCRIBED, BY HIS ATTACHED FRIEND, THE AUTHOR. ADVERTISEMENT. The Drawings for several of the Cuts in this Volume have been taken, by the permission of Mr. Weale, from the admirable Plates annexed to the last edition of Tredgold on the Steam Engine and on Steam Navigation. This acknowledgment is especially due for the Illustrations which abound in this Volume. _London, June, 1840._ [Illustration: LONDON ENTRANCE TO THE BIRMINGHAM RAIL-ROAD.] CONTENTS. CHAPTER I. PRELIMINARY MATTER. Page The Steam Engine, a Subject of popular Interest 4 Effects of Steam 5 Great Power of Steam 7 Object of this Work 9 Disputes respecting the Invention 11 Hero of Alexandria's Machine 13