6lO REVIEWS 



line 1,000 meters lower would bring on glaciation. The effect of glaciation on 

 cyclones and anticyclones is thought to be the same as a cold winter. Reference is 

 made to a paper by F. W. Harmer (reviewed below), which is thought to overrate the 

 effect of wind on climate. 



Gilbert, G. K. and Brigham, A. P. An Introduction to Physical Geogra- 

 phy. 380 pp., 263 Figs. New York: D. Appleton & Co., 1902. 

 The several chapters treat the following subjects in the order named : the earth, 

 the earth and sun, rivers, weathering and soils, wind work, glaciers, plains, mountains 

 and plateaus, volcanoes, the atmosphere, winds, storms, and cyclones, the earth's mag- 

 netism, the ocean, the meeting of the land and sea, life, the earth and man. 



The study of the lands is brought in early in the belief that here is the sure 

 appeal to the students interest and previous knowledge. For the same reason the 

 more familiar features of the land are treated before those that are less common. 

 The treatment, so far as possible, is concrete, and wherever practicable each subject is 

 opened with a type case, in the description of which terminology is called forth and the 

 principles begin to appear. It is believed that physical geography is a subject which 

 lends itself to this method with special effectiveness. The illustrations are especially 

 well selected and are closely correlated with the text. 



Harmer, F. W. The Influence of the Winds upon Climate during the 

 Pleistocejte Epoch. London Quart. Jour. Geol. Soc, Vol. LVII, pp. 

 pp. 405-78, 1901. 



Since changes of wind today cause sudden and marked changes in weather, it is 

 thought that a long-continued change in the course of prevalent winds in the past ages 

 would produce great changes in climate. At present continental areas are hotter than 

 oceanic during summer, and are therefore cyclonic ; they are colder in winter and are 

 then anticyclonic. Regions covered by ice during the glacial period may have been 

 to some extent anticyclonic at all seasons, low-pressure systems prevailing at the same 

 time over the warmer regions south of them and over the adjoining ocean. With such 

 a change oceanic winds with copious rainfall may have prevailed over regions now 

 arid, and mild winters where they are now severe. The paper makes use of weather 

 charts from all over the world in discussing the climatic conditions now prevailing, 

 and draws upon paleontological and other evidence in support of changes of climate 

 to which various parts of the world have been subjected. It seems difficult to explain 

 how the northern hemisphere could have been wholly cold at one stage of the glacial 

 period or wholly mild at another, and it is suggested that no difficulties would arise if 

 there was an alternation of glacial and temperate conditions on the two continents, it 

 being mild in America while glaciation was prevalent in Europe, and vice versa. 

 The paper is naturally very hypothetical, and, as noted above (see Eckholm), the 

 areas of Pleistocene glaciation in Europe and America apparently correspond with 

 areas now traversed regularly by storms. 



Reid, H. F. Variation of Glaciers, Journal of Geology, Vol. IX, pp. 



250-54, 1901; Vol. X, pp. 313-17, 1902. 



The first paper gives a summary of records of glaciers for 1899, the second for 

 1900. The great majority of glaciers are in process of retreat, the world over, but 

 historic evidence shows that their fluctuations are complex and dependent on several 

 factors. 



