December 23, 1910] 



SCIENCE 



923 



duced sufiicient heat not only to melt up their 

 own substance, but a good deal of that com- 

 prising the adjacent lunar surface, and then 

 adds " having established then the fact that 

 giant meteors may have fallen on the earth 

 and may have melted up tracts of country 

 which would be deluged with lava — we may 

 legitimately enquire whether there are any 

 evidences of such occurrences on the earth's 

 surface." He considers that the tufas, lavas 

 and agglomerates in the Archsean of Great 

 Britain, the great lava sheets of the Snake 

 River in Idaho and those of the Kapte Plains 

 of British East Africa may eventually prove 

 to have had such an origin. It is even consid- 

 ered a by no means impossible theory that the 

 New Caledonian nickel deposits are portions 

 of a gigantic meteor which fell long ages ago 

 and which by earth movements has been so 

 crushed and folded that it has all the appear- 

 ance of an igneous dyke. 



The origin of the water on the earth's ex- 

 terior and the part which it plays in modifying 

 the earth's surface, is then taken up and the 

 recent work of various investigators is well 

 presented and discussed. In referring to the 

 fact that during the weathering of rocks the 

 lime which they contain tends to go into so- 

 lution more readily and thus to be more com- 

 pletely removed than the associated magnesia, 

 the author gives it as his opinion that in the 

 processes of solution and redeposition the lime 

 tends to pass upward and outward in the 

 earth's crust while the magnesia most fre- 

 quently passes downward, and adds " Why it 

 goes downward is at present entirely a mys- 

 tery; from an analogy with iron one might 

 suggest that the magnesium of the earth's 

 nucleus exerts an attraction and thus draws 

 it downward," for the author holds that when 

 compounds of iron are dissolved they become 

 ionized and that the great central mass of 

 metallic iron within the earth " must thus 

 exert a pull on the iron in solution, and this 

 pull lasting over innumerable myi'iads of 

 years, yet ever persistent and increasing, 

 would gradually draw downwards the ions of 

 iron as they become formed in the surface 

 water of the earth." 



In treating of the work of underground 

 water, Mr. Schwarz accepts Posepny's theory 

 of the origin of ore deposits and believes it to 

 be the explanation which is now adopted by 

 an ever-increasing body of geologists. 



The subjects of earth folds, the earth's sur- 

 face, cold volcanoes, normal volcanoes, earth- 

 quakes and Archasan rocks are then taken up 

 in succession. Many statements are made- 

 which are highly debatable and some of which 

 are certainly incorrect. The book, however, 

 is well written and is worthy of perusal by all 

 geologists interested in the fundamental prob- 

 lems of the origin of the globe, although one 

 can hardly agree with the author when he 

 says that the work " constitutes an appeal for 

 a return to rationalism after a period of 

 romanticism," for in it the romantic element 

 is developed in a manner as striking and in- 

 teresting as in any of the modern treatises of 

 the more orthodox school. 



Fraxk D. Adams 



A Text-hooh of Psychologij. By Edward- 

 Bradford TiTCHENER. New York, The Mac- 

 millan Co. 1910. Pp. 565. 

 The review of a text-book, like the book 

 itself, reflects a personal equation. The fate 

 of a text is a venture, sharing somewhat 

 in the psychology of advertising. However 

 good the article or inviting the appeal, the 

 test comes in its reception. It is legitimate to 

 appraise a text in terms of its intrinsic merits 

 in form and content and execution; it is 

 equally legitimate to consider its service. Eor 

 the purpose of ever so good a text is bound up 

 with its use. It must first appeal to the in- 

 structor; yet he tests it practically and is 

 prepared to revise his judgment. The com- 

 ments of the users might be gathered by the 

 questionnaire method, with auonynjity to se- 

 cure frankness of statement. 



In a science like psychology, with traditions 

 in the making and doctrines appreciably 

 shifting, yet with essential principles of large 

 scope and suiScient definiteness, the makers of 

 text-books have wide latitudes. It is easy to 

 find agreement that the purpose of the text is 

 to help the student from a casual to a system- 



