162 SIR WILLIAM RAMSAY 



order to weigh this minute quantity of gas with sufficient 

 exactness a balance turning with a load not greater 

 than TO 60 oo milligram was a necessity. Such a balance 

 has been constructed and described by Dr. B. D. Steele 

 and Mr. Grant, of the University of Melbourne, and 

 they showed that a sensibility of -gsoooo milligram could 

 be attained. It would be impossible to convey in these 

 pages any clear idea of the operations involved in the 

 construction of the balance, the collection of the gas to 

 be weighed and the manipulation during the process of 

 weighing. Every student of chemistry and physics 

 should read carefully the description of the work set 

 forth in the paper referred to. All that need be added 

 is the result of the five concordant experiments recorded 

 in the paper, and the mean of them, namely 



227 226 225 220 218 Mean 223 



The density, and hence the atomic weight, of the gas 

 were therefore settled. In view of the character of the 

 emanation, which is a gas belonging to the argon series 

 of inactive elements, Ramsay assigned to it the name 

 niton, with the symbol Nt.< The concluding words of 

 the memoir express very clearly the importance of the 

 result. 



" The research, of which the foregoing is an account, yields a 

 further proof, if such were necessary, of the beautiful theory of 

 the disintegration of the radio-active elements originally advanced 

 by Rutherford and Soddy in 1902. The determination of the 

 density of a gas, even with approximate exactness, has always 

 been regarded as establishing its molecular weight, the accurate 



