543 J @8-1-47210 IN presenting this work to the notice of the public, the author has merely to state, that it had its origin in a desire which he felt to prepare a concise and practical treatise, with a view to facilitate the daily calculations of Engineers, Mill-wrights, and Artisans in general; and by them it is to be hoped it will be duly appreciated, more especially when they consider that the subjects embraced in this small volume-with very few exceptions-have been diffused throughout a number of valuable and extensive works, which are too voluminous to be useful in the field or shop, where they are most needed; and, by reason of their cost, quite out of the reach of the operative mechanic, in general. Besides this, the greater part of mechanical works have been swelled out to an immoderate degree, by scholastic theorems and theoretical problems, too profound and tedious for the practical man-a defect which it is desirous to obviate, and which, it is believed, has been obviated in this work, by commencing with a system of decimals, and carrying on the work, throughout, upon that system. The Tables, which are numerous, will supersede the necessity of seeking for the various methods of calculations, in the hurry of business; and the accuracy of the results given, can be relied upon with the greatest certainty, as they have been thoroughly tested. With regard to the subjects embraced in this work, comment is unnecessary, as every mechanic is well aware that one or the other of them is daily required. The utility of such a work as this, no one will question; and he who would not be a "hewer of wood and drawer of water" to the more intelligent and wellinformed mechanic, must possess, to a considerable extent, the principles and rules embraced in this book; and more especially, if he would be master of his profession, and reputed as one whose skill and decisions can be implicitly relied upon. The principal authors consulted in preparing it for the press, were Adcock, TEMPLETON, GREGORY, GRIER, BRUNTON, "Library of Useful Knowledge," M. MORIN, of the University of Paris, and "Ordnance Manual;" and to the labors of the authors of these valuable works, I freely acknowledge my indebtedness for very much of the valuable matter contained in the following pages. The article on FRICTION, from the pen of Professor MORIN, under the sanction of the French Academy of Arts, will be found invaluable, as it will throw much light upon a subject intimately connected with mechanical arts, and about which little has heretofore been known with any degree of certainty. In my own efforts, I have been materially assisted in the choice of subjects, and hints about their arrangement, by several distinguished mechanics and civil engineers. The success which has attended the former edition of this work, is satisfactory proof that the author's labors have been duly appreciated by a discerning public; and this, it may be inferred, has been the case, the first edition having been disposed of in little more than a twelvemonth; and a second edition being called for, the author has been induced thoroughly to revise the whole throughout, and greatly to augment it with an addition of several very important and useful rules and tables, as well as other useful matter. Hence, it is anticipated that with these improvements, the work will be a still more useful companion for mechanics and practical men, in general. To the mechanic I would say, earnestly endeavor to cultivate your mind, and store it with useful knowledge. Let your leisure hours be devoted to the cultivation of science, and a knowledge of the physical laws, without which, eminence in your profession can never be obtained. And should this little volume facilitate your progress in that praiseworthy employment, the desire of the author will be fully accomplished Rochester, N. Y., September, 1845. J. M. SCRIBNER. RECOMMENDATIONS. Having examined "Scribner's Engineers' and Mechanics' Companion," we have much pleasure in saying that it comprises a great amount of information, both useful and necessary for Mechanics and Engineers. The Author has sought contributions for this work from numerous sources, and from several rare and valuable treatises, and we cheerfully recommend it as well adapted to the want it is intended to supply, viz., of a convenient and acceptable manual for practical men. DANIEL MARSH, Civil } WILLIAM WILEY, Engineers. ROCHESTER, N. Y., Sept., 1845. We cheerfully subscribe to the above recommendation of "Scribner's Engineers' and Mechanics' Companion." MATTHEW M. HALL, Civil Engineer. |