652 EXPERIMENTAL INVESTIGATION OF THE 
similar crucible (one of the same nest,) and with 
a similar mixture of pulverized charcoal and salt, 
and yet showed no trace whatever of magnetic 
action. Hence, it could hardly be imagined that 
the magnetism displayed by the alloy was due to 
iron derived from the crucible. 
34. After subjecting a portion of the alloy (32) 
to dilute nitric acid, and finding no iron in the 
solution, the surface of the metal was washed in 
clean water and thrown into dilute sulphuric acid, 
which, upon the principles of electro-chemistry, 
took up a portion of the copper; and had iron 
been present, would have taken it up also. 
But no indication of that metal appeared by the 
test of gall nut, nor by that of ferrocyanuret of 
potassium ; but the formation of ferrocyanuret of 
copper was manifested in an eminent degree, 
though previously to the introduction of the ferro- 
cyanuret of potassium, scarcely any colour was 
perceptible in the liquor.* 
35. From the facts above described (32, 33, 
34), and, at present, I rest on no other data, I 
* Another portion of the alloy has since been analysed, 
with similar results. 
