■il2 /Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE, 



I. Chkmistry and Physics. 



1. The Behavior of Metallic Copper towards Gases — Sieverts 

 and Krumhhaak have made an elaborate study of tlie solubility 

 of several eominon gases in solid and liquid metallic copper. 

 The behavior of oxygen is well known ; it dissolves in molten 

 copper in the form of cuprous oxide, and upon solidification it is 

 not given off, even in an atmosphere free from oxygen. Nitrogen, 

 carbon dioxide and carbon monoxide are not absorbed either by 

 the solid or molten metal. Hydrogen is absorbed by solid copper 

 at elevated temperatures. The diffusion of this gas through a 

 thin copper tube M'as observed at 650° C. and it was found that 

 the rapidity of diffusion and the solubility increases with the 

 temperature. Above the melting point of copper the solubility 

 of hydrogen in the metal becomes greater, and it increases again 

 with the temperature, at least as far as 1500° C, the temperature 

 to which the measurements were carried. At constant temjjyera- 

 ture the solubilitj^ of hydrogen in the molten copper varies 

 according to the square root of the pressure. Solid copper 

 absorbs no sulphur dioxide, but the liquid metal dissolves it 

 abundantly. This solubility, at constant pressure, increases 

 with the temperature from the melting point to 1500° C, becom- 

 ing more than twice as great at the latter temperature. The 

 solubility of sulphur dioxide, like that of hydrogen, in molten 

 copper, varies according to the square root of the pressure. The 

 agreement of hydrogen and sulphur dioxide in regard to their 

 pressure solubility appears to contradict a theory advanced by 

 van't Hoff to the effect that this peculiar pressure relation is due 

 to a change from the molecular (HJ to the atomic form upon 

 solution, for the SO^, with three atoms in it, should not show the 

 same relation. The increase in solubility of these gases with 

 the temperature shows that their dissolving must take place with 

 the absorption of heat, and this behavior seems to be general with 

 solutions of gases in metals, although it has been observed very 

 rarely in the solutions of gases in water. — Zeitschr. 2^hysilcal. 

 Chem., Ixxiv, 277. h. l. w. 



2. TJie Diffusion of Crude Petroleum through Fidler^s 

 Earth. — The fact that natural oils have been changed in compo- 

 sition by percolation through porous strata in the earth is now 

 well recognized, since various experiments have shown that such 

 fractionation may be carried out by artificial means. Gilpin and 

 Bransky have recently described an extensive series of experi- 

 ments with natural products and mixtures, using tubes packed 

 with fuller's earth, and have confirmed this view of an important 

 cause of the variations in composition of natural oils. They reach 



