40 
[Assemble 
ties will hereafter be added. This sand is of a fine glossy black 
color^ is freely attracted by the magnet, and may thus be freed 
from the sandy particles with which it is usually mixed. When 
it occurs in large quantities, it becomes a valuable ore, as it may 
be easily separated from the sand, and does not require to be sub- 
jected to the processes of roasting and pounding. 
I subjected to analysis a portion of magnetic iron sand from Port- 
Henry, on Lake Champlain, after it had been separated by the mag- 
net. It was found to be pure magnetic oxide of iron, and contain- 
ed no titanium. 
With regard to the occurrence of this sand, it may be observed 
that the theory commonly entertained is, that it has proceed- 
ed from the disintegration of rocks which are contiguous, and 
which abound in crystals of magnetic iron. This is said to be 
the case at West-Haven, Connecticut, where it occurs on the 
beach which forms the margin of the sea shore, while contiguous 
to the beach is a formation of chlorite slate, abounding with mi- 
nnie crystals of magnetic iron. These crystals, liberated from 
the slate and broken by the action ofahe waves, are said to consti- 
tute the magnetic sand of the beach. =^ Now, although the expla- 
nation here given may be applicable to this locality, it cannot, it 
seems to me, be received as a general one. The iron sand fre- 
quently occurs at a great distance from beds of magnetic iron, and 
moreover its chemical composition is oftentimes so very peculiar 
as to forbid the idea that it has been produced in the mode just 
described, 
Bisulphuret of Iron, or Iron Pyrites. — This is among the most 
abundant of the compounds of iron. It sometimes occurs crystalli- 
zed; but when in large quantities, it is often massive. At Ilossie, 
in St. Lawrence county, small crystals are found which have the 
angles of the cube truncated — a form by no means common. 
This mineral, in consequence of the bronze or brass yellow co- 
lor which it usually possesses, is often mistaken for one of great 
value. But its hardness, and the sulphurous odour which it emits 
on being heated, characterize it sufficiently. It is seldom used to 
furnish iron, but is chiefly valued for the sulphate of iron (copper- 
as) which it produces when exposed to air and heat. This manu- 
*Silliman,in Cleveland's Mineralogy.] 
