102 Scientific Intelligence. 



Some other explanation than that of baking by the sun must be 

 offered to satisfy the conditions, as this mud certainly had not 

 been exposed to the drying influence of the sun for several 

 months, — at least since the previous summer and possibly not 

 even then. The only explanation seems to be that the cracks are 

 due to the ground freezing, with expansion, and later thawing, 

 with contraction, beneath the water. It would thus seem pos- 

 sible to explain in this way the occurrence of mud cracks in some 

 other areas where it has been found difficult to account for their 

 presence, by the sun's action. 

 State College, Penn. 



6. Engineering Geology ; by Heinrich Ries, Ph.D. and 

 Thomas L. Watson, Ph.D. Pp. xxvi, 672 ; pis. 104, figs. 225. 

 New York, 1914 (John Wiley & Sons).— The authors of Engin- 

 eering Geology have produced a book which should find wide 

 use. It is neither an economic geology nor the conventional 

 geologic text, but combines many of the best features of both. 

 The engineer with little geologic training may find here an 

 appropriate scientific basis for his work, and the geologist may 

 gain an appreciation of the bearing of his science on problems 

 relating to water storage, sewage disposal, and other features of 

 engineering work. In the chapters on minerals, rocks, structure 

 and metamorphism, soils, surface waters, underground waters 

 wave work, lakes, glaciers, the treatment given these subjects in 

 the elementary textbooks of geology is supplemented by instruc 

 tions for field use in determination of thickness and depth of beds 

 position of faults, flow of streams, strength of materials, etc 

 The book includes special economic chapters on landslides 

 building stones, limes, cement and plaster, clay and clay products 

 coal, petroleum, road materials, and ore deposits. h. e. g. 



7. United States Bureau of Mines ; Joseph A. Holmes, Direc 

 tor. — The following Bulletins have recently appeared (see vol 

 xxxvii, p. 351) : 



No. 42. The sampling and examination of mine gases and 

 natural gas ; by G. A. Burrell and F. M. Seibert. Pp. 116 ; 2 

 pis., 23 figs. 



No. 57. Safety and efficiency in mine tunneling ; by David 

 W. Brunton and John A. Davis. Pp. 271 ; 6 pis., 45 figs. 



No. 67. Electric furnaces for making iron and steel ; by D. A. 

 Lyon and R. M. Keeney. Pp. 142 ; 36 figs. 



No. 68. Electric switches for use in gaseous mines ; by H. H. 

 Clark and R. W. Crocker. 1913. Pp. 38 ; 6 pis., 1 fig. 



No. 79. Abstracts of current decisions on mines and mining, 

 March to December, 1913 ; by J. W. Thompson. Pp. xv, 140. 



In addition to the above a number of Technical Papers and 

 Miners Circulars have also been issued. 



8. Canada Department of Mines. Geological Survey, R. 

 W. Brock, Director. — Recent publications are here noted (see 

 vol. xxxvii, p. 352) : 



