Chemistry and Physics. 485 



SCIENTIFIC INTELLIGENCE 



I. Chemistry and Physics. 



1. Liquid and Solid JRadimn Emanation. — Gray and Ramsay 

 have made some interesting observations upon the remarkable 

 gas which is spontaneously evolved from radium. Having col- 

 lected some of the emanation in a state of fair purity, they com- 

 pressed it in a capillary tube with the very fine bore of 0*08 mm 

 diameter. When sufficiently small, there was seen at the conical 

 point of the tube a minute column of liquid, easily visible under 

 low microscopic power. By altering the volume more or less 

 liquid could be condensed, and by transmitted light all the phe- 

 nomena of condensing and evaporating a liquid could be observed. 

 By transmitted light the liquid appeared colorless like water, but 

 when the illumination from behind was extinguished the liquid 

 was visible by its own illumination as a greenish or bluish green 

 phosphorescent layer, not very luminous, but more so than the 

 gaseous layer. Its vapor pressure was measured at several tem- 

 peratures, but as the gas was not quite pure, an allowance had to 

 be made for this, so that the results given in the following table 

 are only approximate : 



Pressure. Temperature. 



100 mm —74-5° C 



200 —66-1 



500 —53-6 



760 —48-5 



]000 —43-1 



2000 —31-0 



5000 —12-8 



10000 + 1-5 



The density of the liquid was estimated with rough approxima- 

 tion as about 7, assuming the gaseous emanation to be 100 times 

 as dense as hydrogen, and the conclusion was reached that it is 

 considerably more dense than xenon, namely 3 52. While the 

 liquid was only feebly phosphorescent, when it was cooled by 

 touching the tube with liquid air it became brilliant, the color 

 changed to light steel-blue and blazed with light. Continued 

 application of the liquid air caused the color to change, first to 

 white, then to yellow, and finally to orange. Through the micro- 

 scope it looked like a brilliant little arc light. On removing the 

 liquid air the reverse changes in color took place, and these 

 changes could be repeated again and again. There was no doubt 

 that the brilliantly luminous substance was a solid. — Chem. 

 JSTews, xcix, 165. h. l. w. 



2. The Gases Evolved by the Action of Cuprie Chloride upon 

 Steels. — The usual method of determining carbon in steels consists 



Am. Jour. Sci.— Fourth Series, Vol. XXVII, No. 162.— -June, 1909. 

 33 



