THE ENGINEER'S AND MECHANIC'S ENCYCLOPEDIA, COMPREHENDING PRACTICAL ILLUSTRATIONS OF THE MACHINERY AND PROCESSES EMPLOYED IN EVERY DESCRIPTION OF MANUFACTURE OF THE BRITISH EMPIRE. With upwards of Two Thousand Engravings. BY LUKE HEBERT, CIVIL ENGINEER, EDITOR OF THE HISTORY AND PROGRESS OF THE STEAM ENGINE, REGISTER OF ARTS, AND A New Edition, WITH CONSIDERABLE ADDITIONS AND IMPROVEMENTS. IN TWO VOLUMES. "How much useful knowledge is lost by the scattered forms in which it is ushered LONDON: THOMAS KELLY, 17, PATERNOSTER ROW. MDCCCXLIX. PREFACE TO THE NEW EDITION. THE rapid progress of Mechanical Science has developed many most important facts since the first publication of this Encyclopædia. The inventions and discoveries recently made have engaged the sedulous attention of the Editor: for, as the value of each was tested by experiment, a description was accordingly prepared. By the selection of new articles, and care in the abridgement and revision of old ones, this Edition has become systematically enriched: so that it may be received, as fully and faithfully expressing "the existing state of Engineering and Mechanism," adapted to the wants of Practical Men. The unexampled sale of the early edition, and numerous successive reprints, urgently demand another suited to the present state of science. The Author has therefore cheerfully obeyed the commands of his patrons in placing before them in this new Edition the result of his late active and pleasing occupation, in a form re-modelled, enlarged, and, as he believes, considerably improved. The article "RAILWAY" has been entirely re-written, and divided into numerous explanatory Sections. These Sections, although separate and independent, collectively form one continuous and perfect Treatise on this important national subject, capable of easy and immediate reference on the most minute points. Many alterations have been suggested, improvements introduced, and inventions patented, connected with Locomotive Engines and Railway Carriages, calculated, it is hoped, if carried into practice, to prevent the recurrence of future calamitous accidents. On this momentous subject the iv PREFACE TO THE NEW EDITION. Editor has attempted to describe in as clear and minute a manner as possible all Telegraphic and Safety arrangements, with the Atmospheric, and every other contemplated mode of Propulsion. Since any satisfactory account of THE STEAM ENGINE must necessarily extend to a considerable length, it becomes, therefore, very desirable to facilitate references, not only to the description of each species of Engine, but also to those of their various parts. This object has been effected by classifying these great mechanical powers according as they operate, first, by the Elasticity of Steam; secondly, by its Condensation; thirdly, by the Elasticity and Condensation ; fourthly, by the Expansive Principle. Analysis and classification have also been employed throughout the elaborate article "STEAM NAVIGATION," in which the construction of Vessels, of Marine Engines, of Boilers, of Paddle and Screw Propellers, is described, and their individual values asserted, whenever the result of Practice has afforded data for the purpose. The claims to popularity of this Work "have grown with its growth," and ripened into their present maturity by that culture which the most wakeful diligence alone could secure. Articles, rendered obsolete by the advancement of Science, have been cancelled; others, that required little more than partial revision, have been altogether rewritten; and the new matter interspersed is treated in Essays, composed expressly for this Edition. The Engravings, also, have been examined, and additional Illustrations given, simultaneously with the new arrangements of the letter-press; scrupulous attention being paid to the true coincidence of the references in the figures with those of the corresponding descriptions. STAPLE INN, May 30, 1848. LUKE HEBERT. |