Argon, a new Constituent of the Atmosphere. 265 



Sidgreaves (Rev. W.) Notes on Solar Observations at Stonyhurst 

 College Observatory. 8vo. London 1894. The Author. 



Walker (Gr. C.) Customary Law of the Main Tribes in the Lahore 

 District. Vol. XIII. 8vo. Lahore 1894. India Office. 



Map showing Lines of Equal Magnetic Declination for January 1, 

 1895. With a Reprint from the ' Colliery Guardian.' 



The Editor, < Colliery Guardian.' 



January 31, 1895. 



(In the Theatre of the University of London.) 

 The LORD KELVIN, D.C.L., LL.D., President, in the Chair. 



A List of the Presents received was laid on the table, and thanks 

 ordered for them. 



The following Papers were read : 



j "Argon, a New Constituent of the Atmosphere." By 

 LORD RAYLEIGH, Sec. R.S., and WILLIAM RAMSAY, F.R.S., 

 Professor of Chemistry, University College, London. 

 Received January 31, 1895. 



(Abstract.) 

 I. Density of Nitrogen from Various Sources. 



In a former paper* it has been shown that nitrogen extracted 

 from chemical compounds is about ^ per cent, lighter than " atmos- 

 pheric nitrogen." 



The mean numbers for the weights of gas contained in the globe 

 used were as follows : 



Grams. 



From nitric oxide 2*3001 



From nitrous oxide 2'2990 



From ammonium nitrite ...... 2*2987 



* Rayleigli, " On an Anomaly encountered in Determinations of the Density of 

 Nitrogen Gas." ' Eoy. Soc. Proc.,' vol. 55, p. 340, 1894. 



VOL. LVII. U 



