Page:Popular Science Monthly Volume 49.djvu/584

564 popular scientific book. His text is everywhere readable, and his pages never bristle with repellent figures. Mr. Chambers gives a chapter to each of the planets, and one each to the sun, moon, minor planets, and those impressive wanderers, the comets. His mode of treatment gives the reader a personal acquaintance, as it were, with each member of the system by making prominent those characteristics of each which are of chief interest. His chapter on the sun gives especial attention to sun-spots; that on the earth to refraction, twilight, and the twinkling of stars which are phenomena of its atmosphere; that on Mars to its canals that on Jupiter to its satellites; that on Saturn to its rings; that on Uranus, as also that on Neptune, to the story of its discovery. On account of the lively popular interest in comets the chapter on these bodies is made second only to that on the sun in fullness. There are twenty-eight illustrations.

We are disappointed in this book—and glad to be. From its title we inferred that it was a tissue of dogmatic assertion and ecstatic speculation; but examination shows it to contain a clearly arranged and vigorously presented chain of evidence concerning the physical and mental development of man. This is followed by a firm statement of belief in the teachings of the Bible. It consists of a series of lectures delivered on the foundation given by S. F. B. Morse to Union Theological Seminary with one additional chapter. The students who heard the lectures received a valuable addition to their equipment for their life work, and if the persons who are attracted by its title will read the book they will derive probably unexpected benefit from it. After an examination of the manner in which the problem of man's past has been largely solved, Prof. Tyler starts with the amoeba, and in three chapters traces the course of animal evolution up through the invertebrates and lower vertebrates to man. In the next chapter mental development is similarly traced. The general nature of the process by which man has been produced is then discussed. "The animal is at first guided," says Prof. Tyler, "by natural selection through the survival of the most suitable reflex actions, then by inherited tendencies, finally by his own conscious intelligence and will. The first motives are the appetites, but these are succeeded by ever higher motives as the perceptions become clearer and more subtile relations in environment are taken into account." Conformity to environment, as our author describes the process, enables an animal to survive his less fortunate fellows; but if the animal is to progress it must keep such conformity secondary to obedience of the laws of its own structure and being. Man as he is to-day is the outcome of such a line of conduct, and his future upward progress depends on his measuring himself by ever higher and higher standards. It may be questioned whether this adaptation of men and animals to their surroundings ever becomes so largely voluntary as Prof. Tyler seems to represent. In the course of this discussion the author passes out of the field of science into that of religion, and in a chapter specifically devoted to the teachings of the Bible he insists on the reality of revelation and the efficacy of prayer, and gives some practical advice to young preachers. A chapter not forming one of the lectures concludes the volume. This deals with some of the present aspects of evolution, including Nägeli's theory of inherent initial tendency and giving especial attention to Weismann's views.

The widespread use of electricity and the numerous casualties resulting from ignorant or careless wiring make Mr. Robb's book on electrical wiring a very timely one. It has evidently been intended mainly for the use of architects and insurance companies, but the text is so simply and clearly written that the ordinary householder will have no trouble in following it. Insulation, which is one of the most important portions of electric installation, is first considered; then the proportioning of wires to current, and the various systems of distribution and methods of wiring. The