OF WHICH VARIOUS SUBSTANCES ARE SUSCEPTIBLE. 
85 
tween two glass circular checks, so as to obtain a ring of nearly the same 
dimensions as the others, subsequently separating the influence due to the 
glass alone. 
29. The place which the following metals appear to occupy in the scale of 
magnetic energy, and their comparative influence, as resulting from this 
investigation, is given in the succeeding Tables. 
Table IX. 
Metals. 
Rolled 
Silver. 
Rolled 
Copper. 
Cast 
Copper. 
Rolled 
Gold. 
Cast 
Zinc. 
Cast 
Tin. 
Cast 
Lead. 
Solid* 
Mercury. 
Cast 
Antimony. 
Fluid 
Mercury. 
Cast 
Bismuth. 
Compara-~| 
tivemagne- > 
tic energy .J 
39 
29 
20 
16 
10 
6.9 
3.7 
2.0 
1.3 
1.0 
0.45 
Table X. 
Alloys. 
Cast Copper and Zinc 
in equal parts. 
Cast Copper and Bis- 
muth in equal parts. 
Cast Zinc and Bismuth 
in equal parts. 
Comparative } 
energy . . ) 
12 
2.3 
1.4 
30. Although considerable pains have been taken to make the foregoing Table 
as perfect as possible, yet it cannot be considered as anything more than a 
useful approximation ; there are many conditions peculiar to this inquiry to 
be yet investigated, which seem for the present to preclude the possibility of 
obtaining results quite conclusive. The metals employed were in as great a 
state of purity as they could be obtained in the ordinary way of commerce ; 
some of them, more especially the copper, gold, and silver, may be considered 
as very nearly without alloy. 
31. If the preceding investigations are of any importance, they seem to be 
in great measure conclusive, as to the cause of the influence of a rapidly 
* The comparative influence of solid mercury must be taken as a rough approximation ; the bar in 
this ring in air, as nearly as could be ascertained, performed about 150 vibrations between 45° and 
10°; whilst, in an analogous ring of rolled copper it performed about fourteen vibrations; in free 
space in air, it performed 232. 
