348 Proceedings of the British Association. 
Section G.—Mecuanican ScIence. 
President—Davies Gilbert, Esq. 
Vice Presidents—M. 1. Brunel, Esq., John Robison, Esq. 
Secretaries—T. G. Bunt, Esq., G. T. Clark, Esq., William 
West, Esq. 
The discussions were opened by some observations of Professor 
Moseley on the theory of locomotive carriages. 
Dr. Lardner next laid before the meeting many details in il 
to Railroads. Afterwards Mr. Russell of “Edinburgh read an im- 
portant memoir om the traction of boats in canals at different velo- 
cities. 
Tuesday, August 23. 
Section A.—Martuemarics anp Puysicat SCIENCE. 
Mr. Russell gave an interesting statement of a series of experi- 
ments regarding the laws of the Motions of Waves excited in 
ater, 
Prof. 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 An- 
imals 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.—Cuemisrry anp Mineravoey. 
Mr. Exley read a very interesting memoir on a new theory of 
combination, deduced from mathematical data, and demon- 
strated mathematically. 
Dr. Charles 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 oxyge? 
and hydrogen. The gases he examined were carbonic oxide and 
olefiant gas. He found that carbonic oxide was the most powerful, 
and that carbonic acid was always the result. Hence it is evident 
that oxygen and hydrogen are prevented from combining by the s¥- 
perior attraction of the carbonic oxide for the oxygen. Olefiant gas 
he found not to be decomposed, and hence the attraction which pre- 
