XIV. PRESIDENT S ADDRESS. 



Both sides admit a very great amount of folding and crumpling, 

 with subsequent denudation, but Dr. Geikic altogether denies 

 the very extensive faulting which Dr.. Hicks maps. 



Passing now to another subject, I wish to mention the 

 remarkable experiments undertaken by MM. Fouque and Levy, 

 on the artificial formation of minerals and crystalline rocks, by 

 means of purely igneous fusion. The book which describes 

 their methods and the results obtained was published in 1882, 

 but has not, I believe, been much known in England. I am 

 the more disposed to speak of these experiments to-night because, 

 in Birmingham, there are many who can command high tem- 

 peratures, which are kept as nearly uniform as possible for 

 considerable lengths of time, affording great facilities for the 

 repetition of some, at any rate, of the experiments of the French 

 savants. 



Premising that their experiments were only performed on 

 the basic rocks, on account of the much more infusible character 

 of those belonging to the acidic series, a short recapitulation 

 of the results they have obtained may help us in our attempts 

 to follow the course of formation of natural rocks. 



The source of heat employed was a blast gas furnace, the 

 extreme temperature attainable being such that the platinum 

 crucibles ni which the fusions were performed were apt to be 

 melted unless carefully watched. I imagine Fletcher's Injector 

 furnace would answer the purpose admirably, as in his latest 

 paper on heating by gas he speaks of the only limit to the heat 

 obtainable being the resisting power of the fire-clay casings. 

 The blast should be supplied by some means which does not 

 require attention when once started ; such, for instance, as an 

 adaptation of those forms in which water rushing down a pipe 

 draws air down with it, and compresses it in a cylinder at the 

 bottom. The complete fusion of anorthite, leucite, and olivine 

 requires the utmost heat which can be attained to. The authors 

 state that the heat of a glass furnace is not sufficient for the 

 fusion of these minerals, but is about enough for the annealing- 

 process for them mentioned later on. 



