62 Scientific Intelligence. 



the distribution of illumination, and with the application of that 

 theory to the spacing and height of lamps. The second part 

 describes instruments and methods employed for measuring light 

 and illumination. The last part gives a few practical examples 

 of the measurement of illumination. The book is intended for 

 "practical engineers", so that graphical methods are employed 

 throughout, to the exclusion of equations and formulae. " The 

 calculated curves and diagrams have been drawn on a large scale 

 and most of them are accurate within the thickness of the line." 

 The appendix comprises five tables of numbers, useful in photo- 

 metric calculations, and also an explanation of the "Refraction 

 Goniometer." Then follows a fairly complete bibliography of 

 the subject of illumination. On the whole, the book is of a very 

 elementary character. h. s. u. 



12. Kometen und Elektronen ; von Augusto Righi. Deutsch 

 von Max Ikle. Pp. 64. Leipzig, 1911 (Akademische Verlags- 

 gesellschaft M. B. H.). — This is an excellent popular exposition 

 of the modern theory which attributes the phenomena of comets' 

 tails to the action of radiation pressure upon the electrons and 

 ions of which the tail is supposed to be constituted. An interest- 

 ing feature of the pamphlet is the collection, in the last chapter, 

 of the results of observations on the earth's atmosphere during 

 the passage of the earth through the tail of Halley's comet. 

 Though the effects were much less marked than had been expected, 

 and are perhaps in many cases doubtful, yet there are a number 

 of observations recorded which are suggestive and interesting. 



H. A. B. 



II. Geology and Miner a log f. 



1. Publications of the Geological Survey of the United States ; 

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

 Geological Survey are noted in the following list (continued from 

 vol. xxxii, pp. 320, 321): 



Monograph. — The Geology of the Lake Superior Region ; by 

 Charles R. Yan Hise and Charles K. Leith. Pp. 641 ; 49 

 plates, 76 figures. 



Professional Paper No. 73. — The Tertiary Gravels of the 

 Sierra Nevada of California ; by Waldemar Lindgren. Pp. 

 226 ; 28 plates, 16 figures. 



Mineral Resources. — Advance chapters in the production 

 in 1910 of Platinum and allied metals, of Petroleum, of Magne- 

 site, of the Stone Industry, etc. 



Bulletins. — No. 466. Retracement of the Boundary Line 

 between Idaho and Washington from the junction of Snake and 

 Clearwater Rivers northward to the International Boundary. R. 

 B. Marshall, Chief Geographer. Pp. 39 ; 7 plates, 1 figure. 



No. 467. Geology and Mineral Resources of parts of the 

 Alaska Peninsula; by Wallace W. Atwood. Pp. 137; 14 

 plates, 18 figures. 



