of the magnetical Pyrites, &c. 331 
iron for receiving and retaining the magnetic properties. I 
therefore prepared some sulphuret of iron, by adding a large 
quantity of sulphur to fine iron wire, in a moderate red heat. 
The internal colour and lustre of the product, were not very 
unlike those of the magnetical pyrites; and, after the mass 
had been placed during a few hours between magnetical bars, 
I found that it possessed so strong a degree of polarity, as to 
attract or repel the needle completely round upon its pivot ; and, 
although several weeks have elapsed since it has been removed 
from the magnetical bars, it still retains its power, with little 
diminution ; like the magnetical pyrites, however, in its natural 
state, it is not sufficiently powerful to attract and take up iron 
filings. 
But this sulphuret did not contain so much sulphur as the 
magnetical pyrites; I therefore mixed some of it, reduced to 
powder, with a large quantity of sulphur, and subjected it to 
distillation in a retort, which was at length heated until the 
intire bulb became red. 
The sulphuret, by this operation, had assumed very much the 
appearance of the powder of common pyrites, in respect to 
colour; but, in its chemical properties, such as solubility in 
muriatic acid, with the production of sulphuretted hydrogen 
gas, as well as in the nature of the precipitates it afforded with 
prussiate of potash and with ammonia, it perfectly resembled 
the magnetical pyrites. Moreover, by analysis, it was found to 
consist of 35 parts of sulphur and 65 of iron ; and although 
(being in a pulverulent state) its power, as to receiving and 
retaining the magnetic property, could not so easily be examined, 
yet, by being powerfully attracted by the magnet, with some 
