ELEOTRlCIXy, MAGNETISM, AND GRAVITATION. 89 



AFFINITY OF CALORIC FOR MATTER. 



If any one is inclined to doubt whether any affinity really 

 exists between caloric and matter, let him observe the 

 extraordinary effects of condensed carbonic acid; i. e.j 

 carbonic acid gas deprived of the caloric which apper- 

 tains to its gaseous condition. Let him see how mercury 

 is left in the condition of a solid metal by the superior 

 affinity of caloric for the de-calorized gas : how water, by 

 contact with the same, is converted instantaneously into 

 snow or ice — and how the human hand has its texture de- 

 stroyed by the touch alone — not by chemically caustic 

 powers, but by the simple demand of this gas for caloric, 

 which deprives the part of its normal heat before the cir- 

 culation has time to replenish the same. 



The capacity of metals appears to depend upon their rela- 

 tive affinities for caloric; and it is rather interesting to 

 observe how closely the decimals given by philosophers, as 

 representing their individual capacities, agree with their 

 electro-polar powers as witnessed in " mechanical " and 

 thermo-electricity, subjects which have been brought before 

 this Society, and are published in its Memoirs^ and also in 

 the Philosophical Magazine. 



Thus, the capacity of bismuth is stated at '0288, and it is 

 found to be electro-negative to every other metal. 



Lead was shown to be electro-negative to copper. The 

 capacity of the former is represented by 0*02 93, and copper 

 by 0*0949; copper, 0*0949, is electro-negative to iron, '1100; 

 iron, '1100, is electro-positive to zinc, '0927.* Silver, '0557 

 — tin, -0514 — gold, -0298 — platinum, •0314— all take, it will 

 be remembered, a very low place in the scale of amount of 

 current given off. 



There appears to be but one exception to this rule, 



* This was the case in mechanical and thermo-electricity, although with 

 dilute sulphuric acid zinc is positive to iron. Soe my former paper. 



K 



