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II. On the relative powers of various metallic substances as con¬ 
ductors of electricity. By Mr. William Snow Harris, of 
Plymouth, Surgeon. Communicated fy J. Knowles, Esq. 
F. R. S. November 14, 1826. 
Read December 14, 1826. 
The relation between metallic bodies, as conductors of elec¬ 
tricity, has engaged the attention of those whose talents 
have, at various periods, enriched that branch of science; I 
enter therefore upon a further investigation of this interest¬ 
ing subject with much diffidence; but having, by an easy 
method, obtained a series of results, apparently calculated to 
advance our knowledge of it, I am led to hope that a short 
account of my inquiries may be honoured by the notice of the 
Royal Society. 
It has been long since observed by one of the most active 
contributors * to the success of modern science, that the heat 
evolved by a metallic body, whilst transmitting an electrical 
charge, is in some inverse ratio to its conducting power—a 
principle generally admitted, not only as a reasonable deduc¬ 
tion, but also as being established by a great variety of facts; 
I have therefore sought to measure the relative degree of 
heat, so evolved, by various metallic substances in a gazeous 
medium such as air, and thus to discover their precise rela¬ 
tions as conductors of electricity. 
I employed for this purpose a very simple instrument, 
(represented by fig. 1. in the annexed plate,) which may be 
* Mr. Children’s Experiments with a large Galvanic Battery. 
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