72 Scientific Intelligence. 



glacial erosion or protection. The great distinctions in kind 

 between mountain glaciers and continental glaciers are empha- 

 sized, a difference not only of size and Form, but of mode of 

 nourishment, motion and erosion. The over-emphasis which has, 

 owing to its historical development, been put upon mountain 

 glaciation is corrected in this book, two-thirds being given to 

 Arctic and Antarctic glaciation. 



The advance of glacial theory has been accompanied by long- 

 drawn controversy, first in regard to the agency of ice or water, 

 then as to land or marine ice, next of chronologic unity or 

 complexity, and still of erosive competency or incompetency. 

 This has been largely due to the relative lack of comprehensive 

 studies of living glaciers as compared to the intensive study of 

 past glaciation. This being the case, such a book as the present 

 is of especial value, and, as Professor Hobbs remarks, " It is 

 believed that more is gained from setting forth the evidence from 

 one's own viewpoint than by entering into controversy." It is, 

 therefore, a contribution in the spirit of Sir Charles Lyell — "the 

 present is the key to the past." j. b. 



6. Les Variations P'eriodiques des Glaciers, JiV ma rapport. 

 1909 ; redige par Dr. Ed. Bruckner, Professeur a la University 

 de Vienne, President de la Commission et E. Murat, Inspecteur 

 des Foretes a Lausanne, Secretaire de la Commission. Extrait 

 des Annales de Glaciologie, vol. v, pp. lT'7-202, Jan. 1911. — In 

 1909, as in recent years, the world's glaciers, with the exception 

 of those in Scandinavia, exhibited in general a further retreat. In 

 the Swiss Alps, for example, 33 showed a definite retreat and only 

 two a definite advance. The glacier d'Argentiere of the Mont 

 Blanc massif retreated 18 - 6 m between July 23, 1908, and July 

 28, 1909. On the latter date the front of the glacier was 1050 m 

 from the point which it attained in 1819. In Norway the gla- 

 ciers of the central high mountains exhibited a general decrease, 

 but this is matched by an equally general increase in those of the 

 AVestern Coast Range. In Alaska a map of Glacier Bay, based 

 on surveys made in 1907, shows a very marked decrease of gla- 

 ciers during the previous 15 to 20 years, recessions being noted 

 of from 5 to 13*5 kilometers. j. b. 



V. Physik der Erde ; von Dr. M. P. Rudzki, O. Professor an 

 der Universitat Krakau. Pp. viii, 584 ; 5 plates, 60 text figures. 

 Leijizig, 1911 (Chr. Herm. Tauchnitz). — This work consists of 

 fourteen chapters, averaging 41 pages each, on such subjects as 

 the figure of the earth, determinations of gravity and its anoma- 

 lies, density and temperature of the earth's interior, seismology, 

 deformation, waves, tides, ocean currents, rivers, ice and glaciers, 

 the glacial period. The general mode of treatment is to give 

 some pages of descriptive matter and tables of values followed by 

 the mathematical theory. Conclusions from the latter are also 

 given. The volume thus brings together a considerable amount 

 of statistical data of various sorts, such as lend themselves to 

 mathematical treatment, and the lines of that treatment are also 



