February 26, 1904.] 



SCIENCE. 



331 



vantages of the capital as a place of meet- 

 ing are exceptional, as was evidenced by the 

 very enjoyable meeting there last winter. 

 It seems, therefore, that a successful meet- 

 ing may be confidently expected. 



The Physical Societj^ also voted to accept 

 an invitation from the International Elec- 

 trical Congress to hold a meeting in St. 

 Louis during September, 1904, in connec- 

 tion with the meetings of the congress. 



It was the sense of the council that a 

 definite plan shoidd be presented by the 

 council at this meeting looking to the es- 

 tablishment of a western section of the 

 society. 



The papers presented were as follows: 



The Radioactivity of Ordinary Metals: E. 



F. Burton. 



The conducting power acquired by gases 

 when confined in a closed metal vessel has 

 been explained as the result of two causes : 



(1) The radioactivity of the metal walls; 



(2) a penetrating radiation from without, 

 which reaches the confined gas by first pass- 

 ing through the walls of the vessel. Mr. 

 Burton has attempted to eliminate the lat- 

 ter rays by surrounding the vessel with a 

 screen of water. A decrease in the con- 

 ducting power of the confined gas was in 

 fact produced, the decrease being approxi- 

 mately proportional to the thickness of 

 water, and amounting to 32 per cent, when 

 the water was 60 cm. thick. While the 

 vessel was surrounded by a water screen of 

 this thickness its conducting power was 

 tested for different pressures, ranging from 

 19 mm. to 752 mm. The conductivity was 

 found to be almost exactly proportional to 

 the pressure. The author concludes that 

 the conductivity is due to a penetrating 

 type of radiation. 



Does the Radioactivity of Radium depend 

 on the Concentration? E. Rutherford. 

 The intensity of the T-'rays from radium 



bromide was determined by the electrical 



method, first when the salt was in the solid 

 form, and second when dissolved in a solu- 

 tion of radium chloride. The volume occu- 

 pied in the second test was more than a 

 thousand times as great as that in the first. 

 No difference in the intensity of the ^-rays 

 could be detected. Since the intensity of 

 these rays serves as a comparative measure 

 of the activity, the conclusion is reached 

 that the activity of radium is independent 

 of the concentration in the range covered 

 by these experiments. 



The Heating Effect of the Radium Emana- 

 tions: E. Rutherford and H. T. Barnes. 

 The authors described the results of 

 further experiments on this subject. (For 

 the preliminary experiments see Nature, 

 October 29, 1903.) The evolution of heat 

 by the emanation and by the deemanated 

 radium was followed from the time of 

 separation throughout the radioactive life 

 of the emanation. The variation of the 

 heating effects with time was found to be 

 the same as the variation in radioactivity, 

 as measured by the a-rays. Estimating 

 the volume of the emanation released by 

 heating one gram of radium as between 

 6 X 10-* e.c. and 6 X 10-^ c.c, and as- 

 suming its density to be about 100 times 

 that of hydrogen, the authors compute that 

 1 gram of the emanation would radiate 

 during its life an amount of energy lying 

 between 2 X 10" and 2 X 10" gram ca- 

 lories. A pound of the emanation would 

 radiate energy initially at the rate of about 

 100,000 horse power. 



The Phosphorescence of Organic Sub- 

 stances at Low Temperatures: E. L. 

 Nichols and E. Merritt. 

 About 120 substances, chiefly organic 

 compounds of definite composition, were 

 tested for phosphorescence and fluorescence 

 at the temperature of liquid air. Of these 

 only 21 failed to show luminescence at this 

 temperature, while in numerous instances 



