302 



from Baring's Island, of which I will send you a list when I 

 determine the species. In the meantime, I may state with full 

 confidence that the variety called Mya udevallensis, so common a 

 fossil with us and in Sweden, is still a living species at Baring's Island. 

 The truncated form of the shell, and the palliar impressions, are 

 those of the M. udevallensis, and not those of the modern M. trun- 

 cata. On the truth of this you may fully rely, and also that the 

 shells were taken with the animal in them. 



" In the collection there are also some fossil plants from Greenland. 

 They are not, however, carboniferous ; but to my surprise tertiary, 

 and of the same character as those of the Mull formation. I could 

 not find any difference between them and the fossil leaves from Mull, 

 but I cannot at present command the paper by the Duke of Argyll ; 

 however, I have not the smallest doubt of the identity of the forma- 

 tion and species." 



The following Gentleman was elected an Ordinary Fellow : — 



Dr Wyville Thomson, Professor of Geology, Belfast. 



Monday, 2d April 1855. 



Dr CHRISTISON, Vice-President, in the Chair. 



The following Communications were read : — 



1. — Account of Experiments to ascertain the amount of 

 Prof. Wm. Thomson's "Solar Refraction." By Prof. 

 C. Piazzi Smyth. 



After alluding to the excessive difficulty of ascertaining the pre- 

 sence and nature of a resisting medium in space, by planetary or 

 cometary perturbations, the author reminded the meeting of the 

 statements made in those rooms last year, that one of the conse- 

 quences to which the dynamical theory of heat had led him, was 

 the necessity of the existence of a medium filling space ; that such 

 medium was but an extension of our own atmosphere, and must ex- 

 perience a condensation in the neighbourhood of the sun ; and that 

 there must consequently arise a certain refraction of any heavenly 

 body seen through such medium. 



Impressed, therefore, with the importance of endeavouring to get 

 by these means some further light in regard to the long vexed ques- 



