301 



the Constituents of Cleveite Gas, 



It must be admitted that the inference rests on the sup- 

 position that we are right in regarding the hydrogen series 

 as a Principal Series, and this is so far hypothetical, that 

 no Subordinate Series have been found. But if we may 

 assume this, the four Principal Series in the diagram seem to 

 proceed by equal steps towards shorter wave-lengths, from 

 element to element, from hydrogen to lithium. We may 

 perhaps infer similar differences between the atomic weights. 

 This would assign an atomic weight of about 3 to the lighter 

 constituent, and an atomic weight of about 5 to helium ; and, 

 if the two constituents are present in nearly equal quantities 

 in the Cleveite gas, this would agree with the determination by 

 which Cleve found the atomic weight to be 4. 



We are quite conscious that this conjecture about the 

 atomic weights has not yet a satisfactory foundation. Never- 

 theless we believe that it merits some consideration. Inferences 

 from the spectrum of an element to its chemical properties 

 will have a surer basis when a mathematical theory can be 

 given of the form of the oscillation upon which the series 

 depend. 



Appendix. 



In this appendix are brought together all the determinations 

 published by the authors whether in the paper of which the 

 foregoing is a translation, or in the preceding one. 



The Series are here placed in order, a, b, and c belonging 

 to helium gas, and a* ', ¥, c f to the other constituent of Cleveite 

 gas. a and a' are the Principal Series, b and b' the brighter, 

 and c and c' the less bright of the two Subordinate Series. 

 Two corrections have been made in Series (a) which were 

 furnished by the authors in manuscript. 



X. 



1120 ii. 



3888-97 

 3888-76 

 3187-98 I 

 3187-83 f 

 291535 ' 

 2915-22 

 2829-32 ] 

 282916/ 

 276401 1 

 2763-91 j 

 27233 

 2696-5 

 2677-1 



Series (a). 



l/X. 



8928-6-| 

 257138 

 25715 In 

 31367-8 

 31369-3=; 

 33951-8 

 339533d 

 35344-2 

 35346-2 

 36179-3 

 36180-6J 

 36720 

 37085 

 37354 



Difference. 

 16786-5 



5654-2 

 2584 

 1392-9 



834-4 



539 

 365 

 269 



Series (V). 



x. 



2-040 fx. 



5015-73 



3965-08 j 



3964-84 I 



3613-89 



3613-78 



3447-73 



3354-7 



32969 



32583 



3231-3 



3213-4 



l/X. 



4902-0 

 199373- 

 25220-2 

 25221-7: 

 27671-0 

 27671-9- 

 29004-6 

 29809 

 30332 

 30691 

 30947 

 31120 



Difference. 



15035-3 

 5284-4 



2450-2 



1332-7 



804 

 523 

 359 

 256 

 173 



