[Book Reviews]

Abstract

MR. LOCK states that the work before us contains the more elementary parts of the dynamics of a particle and of the statics of parallel forces, arranged with some additions from his “Elementary Dynamics and Statics.” The author's mode of treatment will be familiar to many of our readers, and we need hardly say that Mr. Lock slurs over no difficulty that presents itself to the young student of this difficult subject. We have read the whole of the text with much interest, and pronounce it to be excellent. A boy who has gone through this, and worked out the examples in the manner shown him by the author, will be well equipped for more advanced treatises. A novelty, to which Mr. Lock draws attention, is a new form of “that proof of the formula of accelerated motion which depends upon the idea of average velocity.” This proof appears to be a satisfactory one. There is an interesting combination of Morin's and Atwood's machines, which is likely to furnish a useful illustration to students. The work is split up into eight sections—rectilinear motion, motion in one plane, forces acting at a point, parallel forces, machines, uniform motion in a circle, energy, and the pendulum. The arrangement has been made to meet the special wants of the Science and Art Department. It is suited for any junior students. Article 16 appears to us to be likely to be too difficult for a boy; if so, he can pass on, and return to it subsequently. We have not worked out the examples which accompany the several chapters, and to which answers are given at the end. The following errors we have noted: p. 17, 1. 8 up, dele a in anT; p. 19, 1. 5 up, the first 2 N's should be N′ p. 20, last line, for 252 read 162; p. 52,l. i, it would seem to follow that “when one mass meets another mass of the same velocity” they would not be said to impinge. What would they be said to do? P. 67, the term resolute is defined, reference might be made to p. 92; p. 68, 1. i, dele a; p. 72,1. 8 up, for Q read H; p. 94,1. 7, for an = read +; p. 115, 1. 7 up, read IO - x; p. 139, 1. 2, for 4 read 3; p. 205, last line, numerator, for cos a read sin a; p. 208, 1. 20, supply g p. 246, 1. 8 up, for second g read g ₁. The greater number of these errors are trifling, and will not give the private student much trouble; we have pointed them out because we know what a stumbling-block even slight mistakes are to such students. Their reverence for printed results is often wonderful. The utility of Mr. Lock's “Higher Trigonometry” is greatly hindered by the number of typographical blunders.

Mechanics for Beginners.

Part 1. Dynamics and Statics, By the Rev. J. B. Lock. (London: Macmillan and Co., 1891.)