304 POPULAR LECTURES AND ADDRESSES. 



except that given us by the experiments of Bischoff. 1 

 Bischoff, experimenting on trachite, granite, and 

 basalt, found the solids in these three cases about 

 10 per cent, denser than the liquids. 



This is a subject on which we ought to have 

 better information, and I do think that physicists 

 arc at fault for not having given information 

 regarding it to geologists. Speaking, on the other 

 hand, in the capacity in which you do me the honour 

 to place me, we, the geologists, arc at fault for not 

 having demanded of the physicists experiments on 

 this subject. This time last year I urged that some 

 one should take up the subject. I now renew the 

 suggestion. We have a great Government fund for 

 scientific inquiry. Why do not physicists and 

 geologists unite in an inquiry like this, and apply 

 for assistance out of the Government grant fund ? 

 They should then repeat Bischoff s experiments and 



1 Since this Address was delivered, sonic important experiments 



have been carried out at the request <>f Dr. Henry Muirhead, by Mr. 

 Jo.M-ph Whitley, of Leeds. I lis experiments were made on iron, 

 copper, and brass, and on \\liinstone and granite, and the general 

 result, seemingly (but I believe not at all surely), indicated is that 

 these substances are I,-ss dense in the solid than in the liquid state at 

 ihe inrltin;; temperature. 



