17 JANUARY 1920, Page 22

The Theory of Relativity. By H. L. Brows. (Oxford :

Black- well. is. 6d. not.)—This well-written pamphlet is an attempt " to give a non-mathematical description of some of the loading ideas of the theory of relativity and to emphasize the successive steps in its development." Professor Einstein's theory cannot be stated simply, but Mr. Brose helps the unlearned reader to grasp the fact that it has an important bearing on our concep- tions of the universe. The conclusion that " our space is re- garded as eing finite but unbounded " conveys no definite meaning to the ordinary mind, for which the Fourth Dimension must remain a mystery.