MAGNETIC CHARACTERS OF METALS, &c. 653 
am inclined to think that if any iron could possibly 
have entered the alloy, its quantity must have 
been too small to cause the high degree of mag- 
netic action which the specimen exhibited. 
36. On comparing this alloy of silver and 
copper, with the alloy of iron and antimony, in 
which the weight of the latter metal is only about 
twenty times that of the iron (24), some very re- 
markable circumstances present themselves. In 
the former alloy, where no iron can be detected by 
the usual chemical tests, we have a metal whose 
magnetic action is, at least, twice as powerful as 
that displayed by the alloy of iron and antimony, an 
alloy of which iron constitutes a very considerable 
proportion, and whose presence, had it not been 
previously known, could have been detected by 
the humblest test for ferruginous matter. These 
parallel experiments tend to show either that an 
alloy of pure silver and pure copper is magnetic, 
or that the magnet is a better test for the pre- 
sence of minute portions of iron, in such alloys, 
than any hitherto known in chemical manipulations. 
37. I regret that another piece of unmagnetic 
silver has not yet fallen in my way, to enable me 
to make further investigations on this curious 
4k 
