Page:Popular Science Monthly Volume 51.djvu/725

Rh inapt for science, as that grass grows for cows to feed upon." Theories of organic evolution arose from an effort to combat this philosophy. Everything organic exists by reason of its significance to the organism, but it does not do so through the Darwinian or other apparatus. As to the struggle for existence, the author judges that the view of this conflict is, "as regards Nature, quite gratuitous, and, as regards science, quite abstract." Biologists, however, do not monopolize the conception of a struggle. "Ideas are represented mobbing round the trapdoor under the stage." Motives, faculties, tendencies, movements, all wrestle together. "In all these cases the struggle is not what happens, or what we see, it is the result of the struggle. We have to do with a hypothetical process which we do not observe, and the nature of our judgment is that we mistake ideal abstraction for physiological analysis. The concluding chapter is upon the unity of the organism. The beginning and end of our labor is to find an expression for character. What is it, as distinguished from the characteristics? No answer to this problem is suggested, except by the biological theories which have been dissected. The author did not aim to construct, but to show what errors are developed through the needs of speculative systems. The book is thus mainly an addition to the voluminous literature of biology, and it serves well as a corrective to an overdose of theoretical abstractions.

A pamphlet of about sixty pages, presenting a new hypothesis concerning the structure and rotation of the earth, modestly published by Carl Freiherr Loeffelhoz von Colberg at Munich in 1886, has passed through a second edition, and now appears thoroughly revised and enlarged as the exposition of an elaborate theory. The theory is that the crust of the earth, through the natural difference in the action of the sun's attraction and centrifugal motion upon the two parts, has a motion of its own, different from that of the fluid nucleus beneath it, causing it to slip over it to a greater or less extent, and giving rise to a variety of phenomena which have been observed, but not hitherto explained. In this way the author would account for the shiftings of the pole which geologists have had to suppose; for the changes of climate of which evidence is given by the fossils, particularly by the subtropical fossils in the arctic regions, and—probably—for the nutations in latitude which are now under investigation. He assumes that it is a strong evidence in favor of his theory that it contradicts no natural laws or phenomena so far established, but is entirely in harmony with most geological and biological and many astronomical observations.

Although the author states that this work must not be considered as a petrology, he devotes nearly half of it to describing the several varieties of igneous, aqueous, æolian, and metamorphic rocks, telling how they occur, and what are their constituents. Both the macroscopic and microscopic structure of these rocks are shown in photo engravings from specimens, and their chemical constitution appears in the results of many analyses. The especial purpose of the work is to set forth the processes and results of the natural decomposition of rocks exposed to the atmosphere. After describing the chemical action of water and the air, the mechanical action of water and ice, and the effects produced by plants and animals. Prof. Merrill proceeds to discuss the weathering of typical rocks in special cases—for instance, a granite in the District of Columbia, syenite in Arkansas, diabase in Massachusetts and Venezuela, basalt in Bohemia and France, diorite in Virginia, etc. Various physical conditions that affect the weathering process are next discussed, such as position, exposure, surface contours, structure of rock masses, etc., and there is also a chapter on the rate of weathering as influenced by such conditions and by climate, topography, etc. The remaining hundred pages of the work are devoted to a description of the regolith or body of soils that mantles the solid crust of the globe. The author points out the various kinds of