The _History of Physics in its Elementary Branches_[17] has been prepared by Professor _Cajori_ in the belief that some attention to the history of a science helps to make it attractive, and that the general view of the development of the human intellect gained in reading a history on the subject is in itself stimulating and liberalizing. The author has had in mind Professor Ostwald's characterization of the absence of the historical sense and the want of knowledge of the great researches upon which the edifice of science rests as a defect in the present method of teaching. The subject is treated by periods. In ancient times the Greeks, while displaying wonderful creative genius in metaphysics, literature, and art, being ignorant of the method of experimentation, achieved relatively little in natural science. The Roman scientific writers were contented to collect the researches of Greek professors. Except in a few instances the Arabs did not distinguish themselves in original research. Writers in the middle ages were only commentators, and knew nothing of personal investigation. The physicist of the renascence abandoned scholastic speculation and began to study Nature in the language of experiment. The seventeenth century was a period of great experimental as well as theoretical activity. In the eighteenth century speculation was less effectively restrained and guided by experiments. The nineteenth century "has overthrown the leading theories of the previous one hundred years, and has largely built anew on the older foundations laid during the seventeenth century." The evolution of physical laboratories, first for teachers and then for students, is the subject of the last chapter. [Footnote 17: A History of Physics in its Elementary Branches, including the Evolution of Physical Laboratories. By Florian Cajori. New York: The Macmillan Company. Pp. 322. Price, $1.60.]