Copyright, 1897, by THE COLLIERY ENGINEER COMPANY. Copyright, 1901, 1902, 1904, by INTERNATIONAL TEXTBOOK COMPANY. Entered at Stationers' Hall, London. Arithmetic, Parts 1-4: Copyright, 1893, 1894, 1895, 1896, 1897, 1898, 1899, by THE COL Arithmetic, Part 5: Copyright, 1905, by INTERNATIONAL TEXTBOOK COMPANY. Mensuration and Use of Letters in Formulas: Copyright, 1894, 1895, 1897, 1898, by Principles of Mechanics: Copyright, 1901, by INTERNATIONAL TEXTBOOK COMPANY. Machine Elements: Copyright, 1901, by INTERNATIONAL TEXTBOOK COMPANY. Mechanics of Fluids: Copyright, 1901, by INTERNATIONAL TEXTBOOK COMPANY. Strength of Materials: Copyright, 1901, by INTERNATIONAL TEXTBOOK COMPANY. Elements of Electricity and Magnetism: Copyright, 1894, 1897, by THE COLLIERY PANY. Heat and Steam: Copyright, 1894, 1895, 1898, 1900, by THE COLLIERY ENGINEER All rights reserved. PRINTED IN THE UNITED STATES. 1 24012 PREFACE Formerly it was our practice to send to each student entitled to receive them a set of volumes printed and bound especially for the Course for which the student enrolled. In consequence of the vast increase in the enrolment, this plan became no longer practicable and we therefore concluded to issue a single set of volumes, comprising all our textbooks, under the general title of I. C. S. Reference Library. The students receive such volumes of this Library as contain the instruction to which they are entitled. Under this plan some volumes contain one or more Papers not included in the particular Course for which the student enrolled, but in no case are any subjects omitted that form a part of such Course. This plan is particularly advantageous to those students who enroll for more than one Course, since they no longer receive volumes that are, in some cases, practically duplicates of those they already have. This arrangement also renders it much easier to revise a volume and keep each subject up to date. Each volume in the Library contains, in addition to the text proper, the Examination Questions and (for those subjects in which they are issued) the Answers to the Examination Questions. In preparing these textbooks, it has been our constant endeavor to view the matter from the student's standpoint, and try to anticipate everything that would cause him trouble. The utmost pains have been taken to avoid and correct any and all ambiguous expressions-both those due to faulty rhetoric and those due to insufficiency of statement or explanation. As the best way to make a statement, explanation, or description clear is to give a picture or a diagram in connection with it, illustrations have been used almost without limit. The illustrations have in all cases been adapted to the requirements of the text, and projections and sections or outline, partially shaded, or full-shaded perspectives have been used, according to which will best produce the desired results. The method of numbering pages and articles is such that each part is complete in itself; hence, in order to make the indexes intelligible, it was necessary to give each part a number. This number is placed at the top of each page, on the headline, opposite the page number; and to distinguish it from the page number, it is preceded by a section mark (§). Consequently, a reference, such as §3, page 10, can be readily found by looking along the inside edges of the headlines until §3 is found, and then through §3 until page 10 is found. INTERNATIONAL CORRESPONDENCE SCHOOLS |
