Geology and Natural History. 417 



be measured. In the past great difficulties have been encountered 

 in conducting commercial transactions involving radium salts, as, 

 lacking any definite and accepted standard of quality, some 

 dealers have been in the habit of selling as pure radium salts 

 material of distinctly inferior quality. As the value of radium 

 salts sold in the United States up to the present is probably 

 considerably in excess of five hundred thousand dollars, the 

 importance of having a definite and reliable check on the purity 

 and strength of these preparations is most essential. The plan of 

 the committee, known as the International Radium Standards 

 committee, is to obtain the funds to cover the cost of the 

 primary standard either through the governments or the scien- 

 tific societies of the countries represented on the committee, or 

 possibly through the cooperation of the International Bureau of 

 Standards at Paris, vi^here it is planned to ultimately deposit 

 the Primary Standard. The committee sincerely desii'e the 

 cooperation and assistance of all interested in the matter of the 

 preparation of the present standard and communications in regard 

 to this matter should be addressed to the Secretary of the 

 Committee, Prof. Stefan Meyer, Institut fur Radiumforschung, 

 Waisenhausgasse 3, Vienna IX, Austria. 



B. B. BOLTVVOOD. 



II. Geology and I^atukal History. 



1. Publications of the United States Geological Survey; 

 George Otis Smith, Director. — Recent publications of the U. S. 

 Geological Survey are noted in the following list (continued frona 

 vol. xxix, p. 363) : 



Folio, No. 171. Engineer Mountain Folio : Colorado ; by 

 Whitman Cross and Allen D. Hole. Pp. 13, with 3 colored 

 maps and 15 figures. 



Bulletins. — No. 381. Contributions to Economic Geology, 

 1908. Part II — Mineral Fuels. Marius R. Campbell, geologist 

 in charge. Pp. 559, with 24 plates and 15 figures. 



No. 419. Analyses of Rocks and Minerals from the Labora- 

 tory of the United States Geological Survey, 1880-1908 ; tabu- 

 lated by F, W. Clarke, chief chemist. Pp. 323. 



No. 425. The Explosibility of Coal Dust, by George S. Rice, 

 with chapters by J. C. W. Frazer, Axel Larsen, Frank Haas, 

 and Carl Scholz. Pp. 186, with 14 plates and 28 figures. 



No. 426. Granites of the Southeastern Atlantic States, by 

 Thomas Leonard Watson. Pp. 282, with 27 plates and 20 

 figures. 



No. 427. Manganese Deposits of the United States, with Sec- 

 tions on Foreign Deposits, Chemistry, and Uses ; by Edmund 

 Cecil Harder. Pp. 298, with 2 plates and 33 figures. 



No. 429. Oil and Gas in Louisiana, with a brief Summary of 

 their Occurrence in adjacent States ; by G. D. Harris. Pp. 192, 

 with 22 plates and 21 fignres. 



