646 EXPERIMENTAL INVESTIGATION OF THE 
not appear to be correct, for I have formed very 
perfect alloys of these two metals, in a great 
variety of proportions, and find that when the 
iron does not form even a twentieth part of the 
mass, it is still magnetic, though in a very low 
degree. When the alloy is of equal parts of 
iron and antimony, it is highly magnetic. This 
alloy, when broken, exhibits a dark grey fracture, 
somewhat glittering. It is easily reduced into 
powder by the operation of a file, or by pound- 
ing in a mortar; and what is very remarkable, it 
yields an abundance of deep crimson sparks 
when struck against hard steel. 
25. It has already been stated (17), that pure 
copper is not magnetic; and I must now add that, 
in a very few cases only, have I detected magne- 
tic action in the copper of commerce, although I 
have tested a great number of specimens both in 
the state of sheet and of wire. 
26. In the copper coinage of this country, I 
have never yet met with magnetic action, not- 
withstanding the number of experiments I have 
made on the various copper coins that have been 
struck in the reigns of several Sovereigns. 
