342 DR. W. M. HICKS : A CRITICAL STUDY OF SPECTRAL SERIES. 



Suppose the atomic weight is W and the number of electrons involved is xW. 

 Then the oun is given by 



If another value depends on y electrons 



whence 



which gives the transference. At present these considerations are only of speculative 

 interest, but a numerical illustration is given below (p. 381) in connection with Kr. 



The results obtained in this investigation have given the oun with much greater 

 exactness than any value obtained in [III.], even than that of Ag. The value of 

 q d/uP has been determined [III., p. 404] as near 36175 with Ag = 107'88. I now 

 believe from later work that the true value is closer to this than I thought at that 

 time, but in any case it is far less accurate than the ouns themselves. While, 

 therefore, we can use the ouns to give extremely accurate values of the ratios of the 

 atomic weight of the gases, the actual values in terms of Ag are not so exact, 

 although more accurate than those obtained by chemical means. This statement of 

 course depends on the supposition of the exact proportionality of oun and square of 

 atomic weight. 



The values of S as obtained later are here collected and the atomic weight deduced 

 from them by taking q = 36175. 



Ne. A. Kr. X. . RaEm. 



8 ... 14-4708 -0006; 57-9209 -002; 249'536 '004 ; 611 -0100 '0017 ; 1787'024 -05 



W . . . 20-0005+ -0004; 40-0141 -0006; 83-0543 0006 ; 129-963 -00018 ; 222-259'003 



Chemical. 20 -2 39-88 82-92 130-2 222 to 222 -4 



It will be seen that in all cases the spectral determinations are much closer to 

 integral values than the chemical, except in the case of RaEm as estimated from 

 HONIGSCHMIDT'S value for Ra. In this case, however, the spectral material is 

 defective. It is shown from one of the criteria that a value. of the oun = 1785'23 is 

 just possible but improbable, or = 1783'38 almost impossible. These would give 

 respectively w = 222'148 and 222'033. It is curious also that from the defective 

 observational work for Ra [III., p. 327] the value of S from v t + v a = 254096 = 137<S, 

 whence w = 226'43 is also greater than HONIGSCHMIDT'S and more in accordance with 

 the value obtained by Mme. CURIE. The value for the Emanation is, however, much 

 more reliable than the above for Ra. If, regarded as a whole, the deviations from the 

 chemical values (RaEm excepte.d) are greater than chemists will allow possible, it 



