IN the consideration of a book such as this contribution to “The Progressive Science Series,” it is advisable to ascertain the standard by which it is to be judged. For convenience, three classes of scientific books may be distinguished, each with its own criterion. There are, first of all, the text-books of a more or less didactic character, aiming at putting the student in possession of the salient facts of his subject; then we have the reference books, and in the third class we may place all volumes which aim at presenting aspects of a science in terms which maybe appreciated by the lay as well as the scientific reader. Prof. Newcomb's book belongs to the third of these types, for it is intended to convey to cultivated minds a view of the state of knowledge of the various bodies in the stellar universe. The stars are considered individually and collectively in many of their characteristics and relationships, with particular reference to their general properties and the structure of the sidereal heavens.
The Stars: a Study of the Universe.
By. Pp. xi + 332. (London: John Murray, 1901.) Price 6s.