398 



Scientific Intelligence. 



Winkelman has found (Ann. d. Phys., 6, p. 104, 1901; 8, 

 p, 338, 1902) that the amount of diffusion of hydrogen through 

 palladium and platinum is not proportional to the pressure but is 

 relatively greater with diminishing pressure. He explains this by 

 the theory that the diffusion enters with a dissociation of hydro- 

 gen molecules and that only the hydrogen atom diffuses. This 

 narrows the working pressure. The forcing pressure is dependent 

 upon the difference of the adsorption on both sides of the body. 

 The diffusing quantity is proportional to this difference. Since it 

 is not shown that this difference is strictly proportional to the 

 pressure, and observations prove that it more or less diminishes 

 with the latter, it necessarily follows that the diffusing quantity 

 is not narrowly proportional to the pressure. The theory that 

 the forcing pressure changes through dissociation of the hydro- 

 gen molecule does not appear to be an explanation of the 

 observed irregularity. — Ann. d. Phys., 4, 1904, pp. 74Y-769. 



J. T. 



8. Study of the Radio-activity of Certain Minerals and Min- 

 eral Waters. — In a paper on this subject delivered by the Hon. 

 R. J. Strutt before the Royal Society, there is the following 

 interesting estimate of the quantity of radium in Bath water : 



" According to the estimate of Sir A. C. Ramsay, the late 

 Director of the Geological Survey, the salt annually delivered by 

 the Bath spring would be equivalent in volume to a column 9 

 feet in diameter and 140 feet high. Taking the density to be 

 twice that of water, this would weigh about 500,000 kilograms. 

 The saline residue gives about one-fifteenth the part of the quan- 

 tity of emanation that samarskite gives. Let us assume that the 

 latter contains one-millionth part of radium, which I think is an 

 outside estimate. At that rate the annual delivery of radium by 

 the spring amounts to about one-third of a gram. The volume 

 of gas which the spring delivered is about one hundred cubic 

 feet per day (Williamson, Brit. Assoc. Reports, 1865, p. 380). 



About one-thousandth part of this is helium, so that about 

 three liters of helium are given off daily, or about one thousand 

 liters per annum. The proportion of helium to radium thus indi- 

 cated is of the same order as in radio-active minerals, though 

 somewhat larger. This is in accordance with the view that the 

 spring draws its supplies from the disintegration of such min- 

 erals." — Nature, March 27, 1904. j. t. 



9. Atmospheric Radio-activity in High Latitudes. — A series 

 of determinations of the radio-activity of the atmosphere have 

 been made by G. C. Simpson at Karasjoh, Norway, in 69° 20' 

 N. lat. It was found that the radio-activity was very much 

 greater than in lower latitudes ; the mean for the month being 

 102, or about six times as great as the German mean for the year 

 (Elster and Geitel at Wolfenbuttel), while the highest value was 

 432 or nearly seven times the German maximum. As regards 

 the connection with time of day, the maximum was found to fall 

 in the evening, the means for morning and afternoon being 



