14 APRIL 1900, Page 22

Inorganic Evolution as Studied by Spectrum Analysis. By Sir Norman

Lockyer. (Macmillan and Co. 4e. net.)—This volume gives an account of Sir N. Lockyer's recent inquiries into the " chemistry of the stare." It begins with directions for making a simple spectroscope by which, easily constructed as it is, very interesting observations may be made. The book is, of course, too technical for discussion here, but if its general purport may be expressed in a few words, it is to set forth the action of heat as a condition of the problem. The stars seem to be divisible into three classes, descending in temperature,— " gaseous stars," "metallic stars," and "carbon stars."