Makch 30, 1900.] 



SCIENCE. 



50T 



somewhat unsatisfactory method of pyrometry. 

 Incidentally it may be appropriate (as for in- 

 stance in the case of Violle's famous experi- 

 ments) but it now has little general laboratory 

 value. 



The resistance pyrometer, introduced by Sie- 

 mans and perfected by Callendar and Griffiths, 

 is for shorter ranges of high temperature 

 (0°-1000°) now without a rival in accuracy. It 

 has the additional advantage of continuous reg- 

 istry almost as far down as the absolute zero of 

 temperature. Calibrated with reference to Cal- 

 lendar' s equations by aid of the specially deter- 

 mined boiling point of sulphur (an error was 

 detected in Regnault's value by this very in- 

 strument), it is also a convenient instrument in 

 practice. 



The chapter on thermoelectric pyrometry, in 

 which Le Chatelier is specially interested is 

 naturally very full, at least in relation to the 

 D'Arsonval method of measurement. This is 

 obviously the more practical though the zero 

 methods give a permanent record. Figures are 

 abundantly inserted of the galvanometers, fur- 

 naces, crucibles, and the other necessary para- 

 phernalia of the pyrometric laboratory. 



The chapter on radiation pyrometry is anti- 

 quated and meagre, inasmuch as nothing is said 

 about the remarkable results of Wien, Lummer, 

 Kurlbaum, not to mention Planck and others 

 who are remodeling the whole subject. So also 

 the mention made of the bolometer is altogether 

 inadequate. On the other hand Le Chatelier 

 enters at length into photometric radiation 

 pyrometry which is of secondary interest by 

 comparison. 



The final chapters contain interesting infor- 

 mation on Wedgewood pyroriietry and on Seeger 

 cones, recipes being given in detail. The book 

 closes with the remarkable work which Roberts- 

 Austen is now doing with his self-registering 

 pyrometer and the new differential method of 

 observation. 



The book as a whole is obviously an out- 

 growth of the laboratory and is supplemented 

 by personal observation. As such it needs no 

 further recommendation. 



C. Baeus. 



Brown University, 

 Providence, R.I. 



SOCIETIES AND ACADEMIES. 

 geological society of WASHINGTON. 



The 99th regular meeting was held at the- 

 Cosmos Club, March 14, 1900. 



TJuder informal commurtication's, Mr. J. A. 

 TafF exhibited some asphalts from Indian Ter- 

 ritory, and briefly described their occurrence. 



On the regular program the following papers 

 were presented : 



(1) ' Glacial Sculpture in the Bighorn Moun- 

 tains,' by Mr. F. E. Matthes. 



The glacial cirques on the Bighorn Range are 

 exceptionally well preserved and complete iu 

 outline. The crests and spurs separating them 

 have remained unglaciated, and are remnants 

 of pre-glacial topography. The cirques do not 

 necessarily develop at the heads of the pre- 

 glacial alpine valleys. In numerous cases the 

 upper ends of the latter have remained ungla-^ 

 ciated while cirques have formed lower down. 

 This raises the question : What are the condi- 

 tions necessary for the formation of a cirque ; 

 or, since a cirque is essentially the product of 

 frost-action in the bergschrund, what deter- 

 mines the location of the bergschrund ? 



It was shown that the unglaciated areas above 

 the bergschrunds were covered by quiescent neve 

 during the period of glaciation. They were 

 nivated. The effects of nivation are the accen- 

 tuation of abrupt slopes and the effacing of the 

 pre-glacial drainage lines by deposits of pow- 

 dered rock produced by frost-fracturing along 

 the edges of the neve sheets. The bergschrunds 

 constitute the boundary between the nivated 

 and glaciated areas. 



According to the evidences gathered in the 

 Bighorn Mountains the location of the bound 

 ary line is intimately connected with the depth- 

 of the valleys, or, more strictly, with the depth 

 of the n^ve. That the spheroid of the mean- 

 annual temperature of 32° F. does not influence 

 its location is demonstrated by the fact that 

 cirques and nivated areas exist side by side at all 

 elevations from 10,000 feet up to 13,000 feet. 



The conclusion is that neve may remain sta- 

 tionary or acquire motion at any of these eleva- 

 tions, regardless of the altitude of the spheroid 

 of 32° F. The only factor which determines 

 whether a body of n6ve shall have motion or 

 not is its depth. 



