300 RECORDS. 



Bergen Davis, Latest Theories Relating to the Dis- 

 charge OF Electricity in High Vacua, and Ionization of 

 Gases. 



Summary of Papers. 



Professor Parker presented a brief outline of the various 

 methods used in altitude determinations, showing that all are 

 based on two general methods, triangulation or measurement of 

 atmospheric pressure. In the latter method the determinations 

 are made either by means of the several forms of barometer or 

 the hypsometer. The difficulties attending the use of all of the 

 different forms of barometer were pointed out and the advantages 

 of portability and accuracy of the hypsometer shown. Examples 

 were then given illustrating the extremely satisfactory results 

 obtained with the hypsometer during mountaineering expeditions 

 in the Canadian Rockies last summer. 



Professor Parker has had many years' experience in mountain 

 work, making numerous " first ascents " in British Columbia and 

 Alberta, and he gave as his conclusion that the hypsometer is 

 by far the most convenient and accurate instrument for the 

 determination of altitudes under ordinary mountaineering con- 

 ditions. 



Dr. Kunz in presenting the second paper stated that a 

 naturally fractured piece of pitchblende (uraninite), weighing 

 800 grams, from Pribram, Bohemia, caused the 14^1- carat 

 diamond (tiffanyite),^ to phosphoresce when laid upon it, or even 

 when a piece of window glass, or a board three fourths of an 

 inch thick w^as interposed. The diamond glowed, although 

 more than one inch of space intervened between it and the 

 pitchblende. We have in this instance a substance with a radio- 

 activity of only 2 or 2 1/^ affecting a radio-actively responsive 

 substance, proving that there exists a body of the latter character 

 in this case that responds almost to the unit one of radio-activity. 

 The same specimen of pitchblende did not affect a platinum- 

 barium cyanide screen. Another specimen of pitchblende from 

 Pribram, and others from Johangeorgenstadt, Saxony, and 



'^Science, December 18, 1903. 



