Chemistry and Mineralogy. 385 



to Railroads. Afterwards Mr Russel of Edinburgh read an im- 

 portant memoir on the traction of boats in canals at different velo- 



cities. 



Tuesday^ Augiist 23. 

 Section A — Mathematics and Physical Science. 



Mr Russel gave an interesting statement of a series of experi- 

 ments regarding the Laws of the Motions of Waves excited in 

 Water. 



Professor Powell read a paper respecting the Refractive Indices 

 of several Substances. 



A paper was then read, contributed by Sir D. Brewster, " On 

 the Polarizing Structure of the Crystalline Lens of the Eyes of 

 Animals after Death." 



The Rev. J. W. M'Gauley read an account of " A Series of Ex- 

 periments in Electro-Magnetism, with reference to its application as 

 a Moving Power." 



Section B — Chemistry and Mineralogy. 



Mr Exley read a very interesting memoir on a new theory of 

 chemical combination, deduced from mathematical data, and demon- 

 strated mathematically. 



Dr Chai-les Henry read an account of some experiments made 

 with a view to determine the mode in which certain gases act in 

 preventing the action of spongy platinum upon a mixture of oxygen 

 and hydrogen. The gases he examined were carbonic oxide and 

 olefiant gas. He found that carbonic oxide was the most power- 

 ful, and that carbonic acid was always the result. Hence it is 

 evident that oxygen and hydrogen are prevented from combining 

 by the superior attraction of the carbonic oxide for the oxygen. 

 Olefiant gas he found not to be decomposed, and hence the attrac- 

 tion which prevents the combination is not suflficiently powerful to 

 form any other. This explanation is corroborated by the fact, that 

 it requires a very great proportion of the olefiant gas to produce 

 the efiect. 



Mr Herapath then read a paper on Arsenical Poisons. 



Section C — Geology and Geography. 

 The first paper was " A Classification of the Old Slate Rocks of 

 Devonshire, and on the true position of the Culm Deposits of the 



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