from the special function which it claims by its title. It appears to be an orderly, well-written account of the principles of dynamics, but rather over-burdened with formulre, as, for instance, where a whole page of mathematics, in small print, is devoted to proving that the reading of a weigh beam of an ordinary platform scales is not affected by the position of the load. Apart from these minor blemishes, and under the limitations mentioned above, the work is a favourable specimen of the American college text-book. E. G. C.