MAGNETIC CHARACTERS OF METALS, &c. 647 
27. In the gold and silver coinage, however, 
in which copper forms a constituent part, the case 
is very different. These alloys are nearly all of 
them decidedly magnetic, and, probably, none of 
them entirely free from magnetism. The gold 
coinage, however, displays much feebler magnetic 
action than the silver coinage; indeed in many 
gold coins the existence of magnetism may be 
considered as questionable, whilst in others, and 
especially in those of 1844, magnetic action is 
prominently displayed. 
28. The silver coinage, although in some 
specimens scarcely any magnetic action can be de- 
tected, is generally magnetic in a very eminent 
degree ; and I have found that, when any one 
piece of a particular coinage displays considerable 
magnetic action, the whole of that coinage, as far as 
I have examined it, is similarly magnetic. And, 
on the other hand, when a silver coin has been 
found to be but very slightly magnetic, I have 
but rarely met with one of that particular coinage 
in which any considerable degree of magnetism 
could be detected. 
29. Of the silver coins that have come under 
my notice, a half-crown of William and Mary, 
