THE PRUSSIAN CALCULATOR: BY WHICH ALL BUSINESS CALCULATIONS ARB PERFORMED BY ONE RULE. WITH AN APPENDIX. BY I. A. CLARK, PROFESSOR AND TEACHER OF MATHEMATICS, AND AUTHOR OF THE REVOLVING CALCULATOR, KEY, &c. FIFTH EDITION, ENLARGED AND IMPROVED. Rochester, N. Y.: POWER PRESS OF E. shepard, 201 STATE STREET. Entered according to act of Congress, in the year 1846, by ISAAC A. CLARK, In the Clerk's Office of the District Court of the Northern District of New York. 6-12-45 ADE 3-12-45 52013 PREFACE. During the last five or six years, the Author has made it his especial business to study and teach the science of numbers. In that time he has taught many, both of the young and old, and of both sexes. In his classes he has seen the youth of five, and the silver locks of seventy; and as the author (with the favoring care of Providence) expects to give much of his time to this science as a teacher, he has compiled this work with that object in view. It is true that the design of this work is to teach the principles of numbers used in the various business calculations of the day; yet, at the same time, it will invigorate and enlarge the mind; as it strips the science of Arithmetic of formula and rule, and causes the mind to rely on the great principles on which they are based. While the student stops behind the veil in many of the older systems, he is here invited to raise the curtain, enter the temple and view the interior in its simplicity and beauty. The mind of the pupil is confused, his ideas indistinct, and his powers of analysis never exercised vigorously, while he depends on dead rules. How often is the question put-To what rule does it belong? Or, Give me the rule and I can do it. Why should we not take nature for our guide? There we see but two principles, that of INCREASE and DECREASE; and the varied application of these, will solve every question that admits of solution in the science of numbers. It is also true, that the given question always points to the mode of solution; and this is discoverable by analysis, which if followed will lead to a correct conclusion in every example. I have often observed that the learner feels that with each step of advancement, a new principle was to be acquired, and that he was at each successive step learning a new principle, |