Bumstead and Wheeler — Radio-active Gas. Ill 



interest that small quantities of pitchblende and other uranium 

 minerals are found in Connecticut. The fact, however, that 

 the gas, originally discovered by Professor Thomson in the 

 Cambridge water, has also been found to be mainly, if not 

 wholly, radium emanation,* and that the gas found by Elster and 

 Geitelf in the soil in various places in Germany has the same 

 general characteristics, make it not unlikely that radium may 

 be very widely distributed in the earth, although not always in 

 the surface layers. 



Conclusions. 



1. The radio-active gas found in the ground and in the sur- 

 face water near New Haven is apparently identical with the 

 emanation from radium. If any other radio-active constituent 

 is present it can be only in very small proportion. 



2. The density of the radium emanation, as determined by 

 its rate of diffusion, is about four times that of carbon dioxide. 



3. We were unable to obtain the radio-active gas from mer- 

 cury, recently described by Strutt, and are therefore inclined to 

 attribute his results to an impurity in the mercury used. 



Sheffield Scientific School of Yale University, December, 1903. 



* E. P. Adams, Phil. Mag.. Nov.. 1903. 



f Elster and Geitel, Phys. Zeitsch., July 1, 1903. 



