A KEY TO THE COMMERCIAL ARITHMETIC: IN WHICH ARE GIVEN THE MODE OF ARRANGEMENT, AND SOLUTION OF EVERY QUESTION AND EXERCISE, PROPOSED IN THAT WORK; COMPRISING A System of Mercantile Calculation, ACCORDING TO MODERN PRACTICE. BY JAMES MORRISON, ACCOUNTANT; AUTHOR OF THE COMMERCIAL ARITHMETIC," ELEMENTS OF BOOK-KEEPING," AND ACCOUNTS," ETC. THIRD EDITION, CORRECTED AND IMPROVED BY SAMUEL MAYNARD, EDITOR OF KEITH'S MATHEMATICAL WORKS, ETC. ETC. LONDON: PRINTED FOR LONGMAN, BROWN, GREEN, AND LONGMANS, PATERNOSTER-ROW. EDITOR'S PREFACE. IN preparing for the press a new edition of the Key to Morrison's Arithmetic, the Editor has carefully revised and corrected the original solutions, and has reason to believe that few, if any, errors of consequence have escaped his attention. In accordance, too, with the present improved state of arithmetical science, he has introduced some important alterations, which, it is presumed, will be found alike useful to the learner and acceptable to the teacher. He therefore submits the volume to the public with the confident expectation that, in its present form, it will prove to be in every way more comprehensive and valuable than the former edition. SAMUEL MAYNARD. No. 8. Earl's Court, Leicester Square, London, December 16. 1844. ADVERTISEMENT TO THE SECOND EDITION. In consequence of the New System of Weights and Measures being introduced, several alterations both in the "ARITHMETIC," and in the " KEY," became necessary. In this edition, these alterations have been made, and Solutions to the additional new Questions are given. An APPENDIX is also added, in which Answers are given to all the QUERIES annexed to the several Rules in the " COMMERCIAL ARITHMETIC." The Author's view in proposing these Queries, was to impress upon the mind of the Pupil such rules and directions as were necessary for performing the most useful computations; and the method adopted by him, was to cause the Pupil to write out Answers to the Queries, and to commit them to memory as he went along. of them, for the purpose of checking the Pupils' work with the least trouble; and the Teacher, by referring to the KEY, can do the same. London, January 2. 1826. The Author had a copy AUTHOR'S PREFACE. THE present Volume is intended to complete the "COMMERCIAL ARITHMETIC," as a proper Text-book for the use of Schools and Academies. The judicious and candid Teacher will acknowledge, that when the young Pupil has ready access to the Answers to his Exercises, he is induced to attempt a solution before he has properly considered the nature of the Question. But though this were not the case, and though the Answers might, with propriety, have been annexed to the "Arithmetic," yet the Teacher will save much time, by having at hand the mode of arrangement, and solution of questions, in the System of Arithmetic which he uses in his school. Besides, many of the solutions in this volume are designed to illustrate some of the most difficult and important branches of commercial calculation; and on that account will be useful to the man of business. As Arithmetic is, of all sciences, the most necessary to the Mercantile profession, to teach it well must be a matter of great importance to the community: it is therefore to be regretted, that the Exercises almost universally given in School-books on this subject, and taught in our seminaries, are so different from those in business; that young men, on entering the counting-house, find a great part of what they have acquired to be useless, and need to learn other methods, more adapted for facility and dispatch, before they can be of much service to their employers. This frequently subjects |