354 Dr. C. Henry's Experiments on the Action of Metals 



4. As a last example let the series 



1 — 2 + 4 — 8 4- &c. 



be proposed. Then, comparing with the formula (B.)j we 

 have j: = 2 and b^ c, &c. each = 1, 



. S= -A_= 1 

 x + l 3" 



In a similar way may the sum of 1—4 + 9—16 be readily 

 found. 



March 9, 1835. J. R. YoUNG. 



[To be continued.] 



LVIII. Experiments on the Action of Metals in determining 

 Gaseous Combination, By William Charles Henry, 

 M.D., KR.S* 

 •T^HE property, first discovered by Dobereinerf in spongy 

 -*- piatina of inducing gaseous union, has been recently 

 shown by Dr. Faraday^ to exist also in compact plates of 

 that metal, as well as in plates of palladium and of gold, and 

 hence to be independent of fineness of division or porosity of 

 structure. This important result, while it demonstrated the 

 inadequacy of all theories of the action of piatina that had 

 been before proposed, suggested to Dr. Faraday the idea, that 

 gaseous combination, thus induced, may be due partly to the 

 statical relations subsisting between elastic fluids and the solid 

 surfaces by which they are bounded, and partly to an attrac- 

 tive force, exerted at insensible distances, and probably be- 

 longing to all bodies. By the joint influence of these two con- 

 ditions, the gases, he imagines, are so far condensed on the 

 metallic surface " as to be brought within the action of their 

 mutual affinities at the existing temperature." This ingenious 

 theory, though mainly resting on the fact that perfect purity 

 from foreign matter is the only condition in the metallic sur- 

 face essential to its activity, is further supported by an exten- 

 sive induction of analogous actions. 



Receiving the theory of Dr. Faraday, in so far as it has 

 been developed by him, as correctly representing the nature 

 of these phaenomena, it still remains to assign a cause for the 



* Read before the Literary and Philosophical Society of Manchester; 

 and communicated by the Author. 



•j- [An account of Prof. Dobereiner's experiments, and of those of other 

 chemists, on the same subject, will be found in Phil. Mag. (First Series), 

 vol. Ixii. p. 282 — 292 : see also vol. Ixiii. p. 71, and vol. Ixiv. p. 3. — Edit.] 



J [An abstract of Mr. Faraday's Sixth Series of Experimental Researches 

 in Electricity, containing his observations on this subject, was given in 

 Lend, and Edinb. Phil. Mag., vol. iv. p. 291.— Edit.] 



