328 THE ROYAL SOCIETY OF CANADA 



The Absorption of X 5460.97 A by Luminous Mercury Vapour 



By Professor J. C. McLennan, Mr. D. S. Ainslie, M.A., and 



Miss F. M. Cale, B.A.^ 



(Read May Meeting, 1922) 



Abstract 



In this investigation experiments were made to ascertain what 

 component wave-lengths of those constituting the mercury green line 

 X 5460.97 A are absorbable by luminous mercury vapour. As a 

 result of this investigation it has been shown : 



(1) That when the radiation constituting the green line of 

 mercury is passed through moderately luminous mercury vapour the 

 main component and the components No. ( + 1)AX = 0.0086A and 

 No. (-1)AX = 0.0087^ can be strongly absorbed. 



(2) That no marked absorption by luminous mercury vapour 

 was observed in the case of the other nine components of the green 

 line. 



(3) That of the nine members constituting the magnetically 

 resolved green line it was found that the central undisplaced member 

 was the only one that could be markedly absorbed by luminous 

 mercury vapour. 



(4) That absorption by luminous mercury vapour of the light 

 constitu,ting the green line in the spectrum of mercury affords a 

 means of clearly and easily demonstrating the existence of those 

 components of the line with separations AX = . 0182 A and AX = . 021 

 A, i.e., satellites Nos. ( + 2) and (-2). 



(5) Some considerations have been presented in support of the 

 view that the components of the green line of mercury for which 

 AX =+0.0182^, +0.0086^, -0.0087 ^ and -0.021 .4 may origin- 

 ate in atoms of the element having respectively the weights 197, 198, 

 202 and 204. 



^Miss F. M. Cale has been enabled to proceed with research work through the 

 award to her of a bursary by the Honorary Advisory Council for Scientific and 

 Industrial Research of Canada. 



