Chemistry and Mineralogy. 359 



respecting the tides, and his description of these, Mr Hall stated, 

 that he had been led closely to compare them with the weather; 

 but difficulties to him insurmountable had occurred, when consider- 

 ing the variations of weather in different places at the same time; 

 yet, regarding those in the neighbourhood of Bristol, his conviction 

 was unwavering. Perhaps the varying time at which the tide 

 reaches various places, so fully described by Professor Wheweli in 

 his lecture on Tuesday evening, might assist in solving this diflBi- 

 culty ; and if the attention of others were directed towards it, his 

 end would be attained. 



Mr Ettricke then gave a description of " An Instrument in- 

 tended to observe Minute Changes of Terrestrial Magnetism,'* and 

 of other philosophical instruments. 



Mr R. Addams then made a communication respecting the Vibra- 

 tion of Bells. 



Mr Rootsey then read papers " On the Music of the Greeks, and 

 a System of Mnemonic Logarithms.'* 



Section B. — Chemistry and Mineralogy. 



Dr Daubeny stated, that he had ascertained that the sublimation 

 of carbonate of magnesia was entirely a mechanical process, and he 

 inferred that no support could hence be given to Von Buch's well- 

 known theory of dolomization. 



Dr Dalton then gave an exposition of his views npon the subject 

 of Chemical Notation, and the atomic constitution of chemical sub- 

 stances. 



■ Mr Johnston explained the use of some chemical tables which he 

 exhibited. 



Dr Thomson read a very valuable paper on Mixtures of Sulphuric 

 Acid and Water, in which he shewed that the theory of Irvine re- 

 specting specific heat cannot be true. 



Mr Jones detailed the results of an elaborate Analysis of Wheat, 

 and mentioned that he had formed a new and peculiar volatile fluid 

 by the action of sulphuric acid on wheat. 



Section C. — Geology and Geography. 



A paper was read by the Marquis Spineto on the geographiciil 

 position of Memphis, in Egypt. The state of that city during the 

 time of its long prosperity was first considered ; then the causes of 

 its destruction ; and lastly, the opinions of different travellers re- 



