Geology and Mineralogy. 65 



would seem to supply the demand which has existed up to the 

 present for a work on the subject of radio-activity which is not 

 too technical and which is at the same time trustworthy and 

 entertaining for the average scientific reader. b. b. b. 



13. Das elektrische Bogenlicht.' Seine EntwicMung unci seme 

 physih.dischen Grundlagen ; von Walthkr Bijegon von Cztjd- 

 nochowski. Lief IV- VII, pp. 291-698. Leipzig, 1906 (S. 

 Hirzel). — The earlier parts of this admirably exhaustive work on 

 the electric arc light have already been noticed in this Journal. 

 The four parts now issued carry the work through to its conclu- 

 sion. Of these Parts 4, 5, and 6 continue the historical account 

 of the development of the arc light including the period from 

 1879 to 1900, in which the greatest activity and variety of inven- 

 tion were exhibited, and then from 1900 to the present. The 

 second portion of the work included in Part 7 discusses the 

 theory and practice of the present time, dealing first with the 

 electrodes, then with the lamps and current generators, and 

 finally with the various forms of accessory apparatus which are 

 essential. The work as a whole covers about 700 large octavo 

 pages, is well illustrated, and brings together a vast amount of 

 information which is both scientifically and practically interest- 

 ing and important. 



II. Geology and Mineralogy. 



1. United Slates Geological Survey; Charles D. Walcott, 

 Director. — The recent publication of the U. S. Geological Survey 

 are noted in the following list : 



Folio, No. 140. — Geologic Atlas of the United States. Mil- 

 waukee Special Folio, Wisconsin. Description of the Milwaukee 

 Quadrangle ; prepared under the supervision of T. C. Chamber- 

 lin, geologist in charge ; b}^ William C. Alden. Pp. 12, with 

 2 colored maps and 15 figures. 



No. 141. Bald Mountain-Dayton Folio, Wyoming. Descrip- 

 tion of the Bald Mountain and Dayton Quadrangles ; by N. 

 H. Darton. Glacial Geology, by R. D. Salisbury. Pp. 15, 

 with 7 colored maps and 12 figures. 



Professional Papers, No. 46. — Geology and Underground 

 Water Resources of Northern Louisiana and Southern Arkansas; 

 A. C. Veatch. Pp. 422, with 51 plates and 33 figures. 



No. 51. — Geology of the Bighorn Mountains; by N. H. Dar- 

 ton. Pp. 129, with 47 plates and 14 figures. 



No. 54. — Geology and Gold Deposits of the Cripple Creek 

 District, Colorado ; by Waldemar Lindgre^ and F. L. Ran- 

 some. Pp. xix, 516, with 29 plates (3 in pocket) and 64 figures. 



No. 55. — Ore Deposits of the SilveivPeak Quadrangle, Nevada; 

 by Josiah Edward Spurr. Pp. 174, with 24 plates and 40 

 figures. 



Am. Joub. Sci.— Fourth Series, Vol, XXIII, No. 133. — January, 1907. 

 5 



