FOR TRIGONOMETRICAL, ASTRONOMICAL, AND NAUTICAL CALCULATIONS TO WHICH IS PREFIXED A TREATISE ON LOGARITHMS BY HENRY LAW, PREFACE. THE first part of the following work is intended to have a twofold object-viz., to explain and illustrate the use and application of logarithms for the practical calculator, and to set forth and demonstrate their nature and properties for the Mathematical student. While, therefore, the Theoretical and Practical parts have been kept distinct, so that either might be separately studied or referred to, they have been so written with reference to each other as to form but one connected treatise, which the student, who really wishes to become thoroughly acquainted with the subject, should entirely peruse. For, although a knowledge of their mathematical properties is not essential to a knowledge of their use, yet they are so intimately connected that the acquirement of one greatly facilitates the acquirement of the other. The second part of the work, while complete within itself, is intended also to form a companion or supplemental volume to two others of Mr. Weale's Rudimentary Series; namely, to the Rudiments of Nautical Astronomy, and the Rudiments of Navigation. In order to the attain prefixed to the Tables of this part as is sufficient for showing the manner in which they are to be used, and the purposes for which they are to be employed; and such examples of their application have been added as will, it is hoped, remove all difficulty in their employment. The Tables of the Logarithms of Numbers, and of Logarithmic sines, tangents, &c., have been reprinted from the third edition of Gregory's Mathematics for Practical Men; and the Table of Proportional Parts, first given in that work, has been arranged in a new and more convenient way in the present Tables. Tables I. to V. will be found of considerable service for general purposes of calculation, in addition to their application with Tables VI. to XVIII. to the important purposes of Navigation and Nautical Astronomy. The remaining Tables will be found of constant use in all mathematical investigations involving trigonometrical expressions; these are principally compiled from Hutton's Mathematical Tables. In the preparation of the Tables and in their progress through the press, every care has been taken by careful and repeated reading to insure accuracy, an object which it is confidently hoped has been successfully attained. OLD WINDSOR, July, 1850. II. L. Owing to the large number of copies which have been printed the stereotype plates had become much worn. For the present edition they have been very carefully examined and restored, and all the errors which upwards of thirtythree years' use of the Tables has discovered have been corrected. H. L. |