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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 ab- 

 stract." Biologists, however, do not monop- 

 olize the conception of a struggle. " Ideas 

 are represented mobbing round the trapdoor 

 under the stage." Motives, faculties, tenden- 

 cies, movements, all wrestle together. " In 

 all these cases the struggle is not what hap- 

 pens, or what we see, it is the result of the 

 struggle. We have to do with a hypothet- 

 ical process which we do not observe, and 

 the nature of our judgment is that we mis- 

 take ideal abstraction for physiological anal- 

 ysis. 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 prob- 

 lem 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 litera- 

 ture of biology, and it serves well as a cor- 

 rective to an overdose of theoretical abstrac- 

 tions. 



A pamphlet of about sixty pages, present- 

 ing a new hypothesis concerning the struc- 

 ture and rotation of the earth, modestly pub- 

 lished by Carl Freiherr Loeffelhoh von Col- 

 berg at Munich in 188G, 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 dif- 

 ference in the action of tlie' 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 ex- 



* Die Drehnngen der Erdkruste in geologischen 

 Zeitraumen (Revolutions of the Earth's Crust in 

 Geological Ages). A new geologico-astronouiical 

 theory. By Carl Freiherr Loeii'elholz von Col- 

 berg. Munich : J. A. Finsterlin's SucceesorB. 



tent, and giving rise to a variety of phenom- 

 ena which have been observed, but not 

 hitherto explained. In this way the au- 

 thor 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 as- 

 sumes 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 ob- 

 servations. 



Although the author states that this 

 work * must not be considered as a petrol- 

 ogy, he devotes nearly half of it to describ- 

 ing the several varieties of igneous, aqueous, 

 asolian, and metamorphic rocks, telling how 

 they occur, and what are their constituents. 

 Both the macroscopic and microscopic struc- 

 ture of these rocks are shown in photo en- 

 gravings 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 re- 

 sults of the natural decomposition of rocks 

 exposed to the atmosphere. After describ- 

 ing 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 weath- 

 ering of typical rocks in special cases for 

 instance, a granite in the District of Colum- 

 bia, syenite in Arkansas, diabase in Massa- 

 chusetts and Venezuela, basalt in Bohemia 

 and France, diorite in Virginia, etc. Va- 

 rious 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 descrip- 

 tion of the regolitb or body of soils that 

 mantles the solid crust of the globe. The 

 author points out the various kinds of de- 



* A Treatise on Rocks, Rock- Weathering, and 

 Soils. By George P. Merrill. New York : The 

 Macmillan Co. Pp. 411, 8vo. Price, $4. 



