Geological Society. 311 



taking place at that temperature; and that would involve the 

 supposition that it was the 10-atom salt in solution before. The 

 difference in our results springs from the different modes of 

 working. Lowel always maintained a large excess of anhydrous 

 present, whilst I added the salt in small portions, carefully avoid- 

 ing throwing down any anhydrous. This is pretty easily done by 

 keeping up a very rapid motion so as to prevent the liquid from 

 getting heated too much at auy point. It seems to me that in 

 any case, as the six ounces fairly dissolved, the solubility of the 

 10-atom salt should be given in those proportions. Further 

 experiments would, I have no doubt, give still higher figures. 



Ln conclusion, I would remark that if the crystal theory of 

 these solutions be accepted we have a test of great delicacy in 

 these drops for the presence of the salts. Interesting experiments 

 might be made as to the power of air to disseminate crystals of 

 a salt thrown into it in fine powder. 



De Coppet has already remarked that the mass of a solution 

 exerts some influence on its crystallization, and I have shown that 

 the form of the vessel also has a decided effect. The effect again 

 of different vibrations on different solutions is worth trying, as 

 there seems to be no reason why the hyperacid sodium salt 

 should be an exceptional case. 



A good deal of work has yet to be done before we arrive at a 

 satisfactory explanation of these obscure phenomena. 



GEOLOGICAL SOCIETY. 

 [Continued from p. 236.] 

 February 7th, 1877.— Prof. P. Martin Duncan, M.B., F.R.S., Pre- 

 sident, in the Chair. 

 The following communications were read : — 



2. " On new Species of Belemnites and Salenia from the Middle 

 Tertiaries of South Australia." By Ralph Tate, Esq., F.GLS., Pro- 

 fessor of Natural Science in the University of Adelaide. 



3. " On Mauisaurus Gardneri (Seeley), an Elasmosaurian from 

 the base of the Gault at Folkestone." By Harry Grovier Seeley, Esq., 

 F.L.S., F.Gr.S., Professor of Geography at King's College, London. 



February 21st, 1877.— Prof. P. Martin Duncan, M.B., F.R.S., 

 President, in the Chair. 



The following communications were read : — 



1. "On possible Displacements of the Earth's Axis of Figure pro- 

 duced by elevations and depressions of her surface." By the Rev. 

 J. F. Twisden, M.A., Professor of Mathematics in the Staff College. 



The object of this paper is to discuss the question of the possi- 

 bility of a displacement of the earth's axis of figure under the con- 

 ditions indicated in a question (suggesting the possibility of a dis- 

 placement of the axis of figure from the axis of rotation amounting 

 to 15° or 20°) put to mathematicians in a passage of the Anniversary 

 Address delivered to the Geological Society by its President, J. 



