208 



Presents. 



[Jan. 16, 



that the proportion of helium is less than 3 per cent. ; so that there 

 would be less than 3 X 10~ 4 of helium in the atmosphere. The 

 experiment about to be described was an attempt to carry the 

 matter further, and is founded upon the observation by Professor 

 Ramsay, that the solubility of helium in water is only 0*007, less 

 than one-fifth of that which we found for argon.* 



It is evident that if a mixture of helium and argon be dissolved 

 in water until there is only a small fraction remaining over, the 

 proportion of helium will be much increased in the residue. Two 

 experiments have been made, of which that on October 6, 1895, 

 was the more elaborate. About 60 c.c. of argon were shaken for 

 a long time with well boiled water contained in a large flask. 

 When the absorption had ceased, the residue of 30 c.c. was sparked 

 with a little oxygen until no nitrogen could be seen in the spec- 

 tram. It was then treated a second time with boiled water until its 

 \ olume was reduced to 1J c.c. With this vacuum tubes were charged 

 by my son at two different pressures. In none of them could D 3 be 

 detected; nor was there any marked difference to be seen betweeu 

 the spectra of the washed and tbe unwashed argon. If helium be 

 present in the atmosphere, it must be in very small quantity, prob- 

 ably much less than a ten- thousandth, part. 



Presents, January 16, 1896. 



Transactions. 



Athens: — British School. Annual. No. 1. 4to. London [1895]. 



The Committee. 



Austin : — Texas Academy of Science. Transactions. Vol. I. 

 No. 4. 8vo. Austin 1895. The Academy. 



Baltimore: — Johns Hopkins University. Circulars. Vol. XV. 

 No. 122. 4to. Baltimore 1895. The University. 



Belgrade: — B.oyal Academy of Servia. Spomenik. Nos. 26,27. 

 29. [Servian.'] 4to. Belgrade 1895 ; Glas. No. 48. [Servian.] 

 8vo. Belgrade 1895. The Academy. 



Berlin: — Deutsche Chemische Gesellschaft. Berichte. 1895. 

 Nos. 11—18. 8vo. Berlin. The Society. 



Gesellschaft fur Erdkunde. Yerhandlungen. Bd. XXII. 



Nos. 8—9. 8vo. Berlin 1895. The Society. 



Physikalische Gesellschaft. Die Forfcschritte der Physik im 

 Jahre 1889. 8vo. Braunschweig 1895. The Society. 



Brunn : — Naturforschencler Verein. Verhandlungen. Bd. XXXIII. 

 8vo. Brunn 1895 ; XIII. Bericht der Meteorologischen Com- 

 mission. 8vo. Brunn 1895. The Society. 



* ' Phil. Trans.,' A, vol. 186, p. 225, 1895. 



