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A CONVENIENT REFERENCE BOOK
FOR ALL PERSONS INTERESTED IN
Mechanical Engineering, Steam Engineering, Electrical Engineering, Railroad Engineering, Hydraulic
Engineering, Bridge Engineering, Etc.
INTERNATIONAL CORRESPONDENCE SCHOOLS
7th Edition, 389th Thousand, 27th Impression
INTERNATIONAL TEXTBOOK COMPANY
COPYRIGHT, 1893, 1894, 1897, 1898, 1900, BY THE COLLIERY
ENTERED AT STATIONERS' HALL, LONDON
ALL RIGHTS RESERVED
The first edition (2,000 copies) of the handbook of which this is the outcome was issued in October, 1893, in the form of a notebook containing 74 printed pages, with about the same number of blank pages for memoranda, under the title of Mechanics' Pocket Memoranda. The little book proved so popular that a new edition (10,000 copies) enlarged to 110 pages was issued 8 months later, In June, 1897, the blank pages were discarded, the work was entirely recast and enlarged to 318 pages, and the edition (third) consisted of 25,000 copies. Before printing the fifth edition (March, 1898), a large amount of matter relating especially to Plumbing, Heating, and Ventilation and the Building Trades was taken out, replaced by tables of logarithms, trigonometric functions, etc., together with directions for using them, and other new matter, the result being to confine the work more particularly to the different branches of engineering and mechanics.
It has been the aim of the publishers, from the first, to present to the public a handbook of a size convenient to carry in the coat or hip pocket-a pocketbook in reality-which would contain rules, formulas, tables, etc. in most common use by engineers, together with explanations concerning them and practical examples illustrating their use. We have not endeavored to produce a condensed cyclopedia of engineering or of any branch of it, but we have striven to anticipate the daily wants of the user and to give him the information sought in the manner best suited to his needs. Our aim has been to meet the necessities not only of the engineer but of all in any manner interested in engineering, and in accomplishing this we have selected that rule, formula, or process which was, in our opinion, best adapted to the circumstances of the case, describing it fully, giving full directions how and when to use it, and not mentioning other methods (when such were available); in other words, we have made the selection instead of leaving the choice to the judgment of the user, which is frequently at fault. The exceedingly large sale proves that the idea was popular and has vindicated our judgment. We hope that succeeding editions will meet and merit the same approval that has been accorded those preceding.
The present (seventh) edition contains the most convenient table of powers, roots, and reciprocals of numbers yet printed. This table was arranged and computed by us and will be of great use to all having occasion to use it.
INTERNATIONAL CORRESPONDENCE SCHOOLS. December 1, 1903.
of circles, Table of. Avoirdupois weight..
26 19 239 250 230
2 243 263 253
2 82-90 119 82 3
B. Batteries, Storage..
storage, Regulation of.
of a line, Deduced
152 152 152 152 152 276 283 193 241 140 209 204 152 249 140