KNIGHT'S AMERICAN MECHANICAL DICTIONAL Y A DESCRIPTION OF TOOLS, INSTRUMENTS, MACHINES, PROCESSES, NICA AND DIGEST OF MECHANICAL APPLIANCES IN SCIENCE AND THE ARTS. TICAL COPYRIGHT, 1872, BY J. B. FORD AND COMPANY. COPYRIGHT, 1876, BY HURD AND HOUGHTON. RIVERSIDE, CAMBRIDGE: H. O. HOUGHTON AND COMPANY. 16151 PREFACE. 11920 MORE than twenty years ago the author commenced collecting memoranda of mechanical and scientific information with a view to forming a systematic digest, but without any well-defined prospect of its publication. Somewhat over four years ago he was requested by the present publishers to undertake the work which is now put forth, and since then has devoted to it the principal part of his time. While engaged in this duty, much encouragement has been afforded by repeated assurances that there was great need of such a work, and by ready and valuable assistance from personal friends of the author, experts in various departments of science and industry. After carefully considering the mode of presentation, it was thought best to adopt the form of a Dictionary, -a "word-book," which describes things in the alphabetical order of their names, and not that of an Encyclopædia, which considers them in the order of their scientific relation. A Dictionary answers directly the questions, propounded; an Encyclopædia is a collection of treatises. The aim has been to place the information in the most systematic order, so that any specific point of detail may be readily reached when required. A book or a mind, though a closely packed repository, unless order has supplemented industry, is unavailable in an emergency, reminding one of "the fool i' the forest": As to the general scope of the book and the method pursued in its preparation, it must, in the main, speak for itself. While the greater portion of the work is occupied, of course, by details of solid import, there is some little romance and a great deal of interest in the study of the History of Inventions. Without deviating into irrelevancy, the author has sometimes become "A snapper-up of unconsidered trifles," worthy of a more careful estimate. "First the blade, then the ear, then the full corn in the ear," is the natural order in invention, as well as in other departments of mind and in the Kingdom of Grace. When we read Pliny's account of the reaping-machines in the plains of Rhotia, about A. D. 70, we wonder that, the idea once blocked out, the machine should after |
