1899] AMERICAN INTRODUCTION TO AGRICULTURE 407 



AN AMERICAN INTRODUCTION TO AGRICULTURE. 



The Principles of Agriculture. Edited by L. H. Bailey. 8vo, pp. xvi. + 

 300, with 92 figures. New York : The Macmillan Co. London : 

 Macmillan and Co., 1898. Price 4s. 6d. 



This is a book of unequal merit, better in the conception than the execution. 

 Designed for Americans, it is written in the American language, and its 

 "roiley streams" and "fitted fields" will hardly be recognised by English 

 readers. Work done outside America is ignored, nor does any English book 

 find a place in the bibliographical references. Opinions may differ as regards 

 the wisdom of this, but there can be no difference of opinion in regard to 

 matters of fact. There is manifestly a double error in the statement that haws 

 are mixed with sand in autumn and sown in the following spring, the operation 

 being known as "stratification." One wonders how the thousands of sheep 

 annually fed on pasture or turnips, without access to water, manage to exist, if 

 "no food contains so much water that it can be used by the animal to supply 

 its needs both for water and solid matters " ; and what have Scottish dairy 

 farmers to say to the statement that " cattle shpuld not be fed (sic) hay com- 

 posed wholly of timothy and similar grasses " 1 The frequency of such errors 

 makes the book unsuitable for students. W. S. 



The American Geologist for January 1899 is remarkable for its review of 

 the life and work of Prof. E. D. Cope, written by Helen Dean King of Bryn 

 Mawr, Pennsylvania. The bibliography, extending to 815 entries, will be of 

 service to every naturalist. It is noteworthy that almost the whole of Cope's 

 scientific contributions, from 1859 to his death in 1897, should have been 

 devoted to the vertebrata. Few naturalists of his time, and probably none in 

 the first half of this century, could show such a concentration of energy, 

 combined with so large a literary output. 



In the same number Mr. Manson publishes his " Laws of Climatic Evolu- 

 tion," in which he urges that an Ice Age occurs in the history of a cooling 

 planet, at the period when the internal heat ceases to affect the surface- 

 temperatures, but when the vapour from the warm oceans still shields the earth 

 from solar heat. As this vapour is deposited in the form of snow upon the 

 land-surfaces, which cool most rapidly, glacial conditions result, followed by a 

 steady warming of the earth, as the atmosphere becomes free from clouds. In 

 time, as the oceans become warmed by the sun, the new cloud-layers tend to 

 check the general rise of temperature. The old arguments about the uniformity 

 of tropical conditions in Mesozoic and Palaeozoic times are put forward as 

 beyond dispute ; and the numerous authorities quoted give the essay a more 

 magisterial air than it might otherwise possess. 



In the January number of the Psychological Review (vol. vi. No 1), besides 

 an interesting address by Prof. Miinsterberg on " Psychology and History," and 

 an elaborate paper entitled "A study of the relations between certain organic 

 processes and consciousness," dealing mainly with circulation and respiration, 

 Mrs. Ladd Franklin contributes an admirable resume of Prof. G. E. Midler's 

 theory of the Light-sense. This theory has some genetic relationship to that of 

 Hering, but is worked out on independent lines and with different postulates. 

 For the antagonistic processes of assimilation and dissimilation Prof. Midler 

 substitutes the conception of reversible chemical action. We recommend all 

 those interested in fascinating and difficult problems of colour vision to peruse 

 this summary of Prof. Midler's thesis. 



The American Journal of Psychology for last October (vol. x. No 1) contains 

 an elaborate and, it would seem, carefully conducted investigation on the 

 applicability of Weber's Law to Smell (E. A. M'C. ( ramble). The subject is too 

 technical to render a brief description of methods and results possible. We 

 must content ourselves, therefore, with directing the attention of those interested 



