686 



SCIENCE 



[N. S. Vol. XLIV. No. 1141 



others cause a decrease, followed by an in- 

 crease, of permeability. In a properly bal- 

 anced solution the permeability remains 

 normal. Cell walls may be semipermeable to 

 an extent which renders them important in 

 such experiments. 



Point Sets and Cremona Groups. Part III.: 

 Arthur A. Coble, Department of Mathematics, 

 Johns Hopkins University. The group G% 2 

 is used in the problem of determining the 

 lines of a cubic surface. The determination 

 differs from that of Klein. 



The Interferences of Spectra both reversed 

 and inverted: Carl Barus, Department of 

 Physics, Brown University. 



Sex Inter grades in a Species of Crustacea: 

 Arthur M. Banta, Station for Experimental 

 Evolution, Carnegie Institution of Washing- 

 ton. The author has collected a large amount 

 of data on several species of Cladocera which 

 is interesting because of the remarkable array 

 of sex forms, the stock in general consisting of 

 perhaps 40 per cent, normal males and about 8 

 per cent, normal females, the remainder being 

 intergrades with almost every combination of 

 sex characters. 



Some Problems of Diophantine Approxima- 

 tion a Remarkable Trigonometrical Series: 

 G. H. Hardy and J. E. Littlewood, Trinity 

 College, Cambridge, England. A series is 

 given which is never convergent or summable 

 for any value of 6, and is accordingly not a 

 Fourier's series. And further a function is 

 found which does not possess a finite differen- 

 tial coefficient for any value of 0. 



Steric Hindrance and the Existence of Odd 

 Molecules (Free Radicals) : Gilbert N. Lewis, 

 Chemical Laboratory, University of Cali- 

 fornia. It is contended that the hypothesis 

 underlying the somewhat elusive phrase 

 " steric hindrance " should not be introduced 

 until phenomena are known which can not be 

 so well explained in other ways. It is shown 

 how the so-called free radical of organic 

 chemistry may be explained independently of 

 the hypothesis of steric hindrance. 



Newton's Method in General Analysis: 

 Albert A. Bennett, Department of Mathe- 

 matics, Princeton University. An extension 



to general analyses of special algebraic work 

 of H. B. Fine. 



The Cobaltammines : William D. Harkins, 

 E. E. Hall and W. A. Eoberts, Kent Chemical 

 Laboratory, University of Chicago. The 

 authors have determined accurately the freez- 

 ing-point lowerings caused by eight different 

 cobaltammine salts, and have derived from the 

 results the number of ions into which each 

 salt dissociates. These are found to be in ac- 

 cordance with Werner's theory. 



National Research Council: Report of the 

 First Meeting of the Council. Eeports of 

 meetings of the Executive Committee. Or- 

 ganization of the Research Council (as at pres- 

 ent constituted). 



Edwin Bidwkll Wilson 



Massachusetts Institute of Technology, 

 Cambridge, Mass. 



THE AURIFEROUS GRAVELS OF THE 

 SIERRA NEVADA 



The origin and the natural distribution of 

 the $300,000,000 of gold that has been mined 

 from the Tertiary placer gravels of the Sierra 

 Nevada of California is the subject of a re- 

 port by Waldemar Lindgren, which has been 

 published by the United States Geological 

 Survey as Professional Paper 73. 



The Geological Survey's studies of the Ter- 

 tiary placer deposits of the California Sierra 

 began in 1886 and were concluded about 15 

 years later. During this period 22 quad- 

 rangular areas were topographically mapped 

 and 14 of these were studied in geologic de- 

 tail and the results published by the survey in 

 geologic folios. Professional Paper 73 in- 

 cludes the salient features of this earlier work, 

 most of which was done by Mr. Lindgren him- 

 self. This report, thus comprehensive in geo- 

 graphic scope and minute in geologic detail, 

 is believed to be the most complete and thor- 

 ough description of a great placer-gold prov- 

 ince ever published. 



In the main the report is a detailed descrip- 

 tion of the entire area covered, including the 

 gold placer gravels, but Mr. Lindgren's gen- 

 eral account of the tremendous earth forces 

 that built up the Sierra and of the processes 



