20 
[Assemble 
toxide and peroxide of iron in variable proportions. The former 
of these oxides is composed of 77.23 metallic iron, and 22.77 of 
oxygen, in 100; the latter, of 69.34 metallic iron, and 30.66 oxy-^ 
gen. Pure protoxide of iron is not found in nature, and no ore 
at present known contains more than 72 or 73 per cent of metallic 
iron; the rest being oxygen, which is driven off in the form of 
gas, during the reduction. The remark of Professor Cleaveland 
that the magnetic oxide of iron sometimes yields from 80 to 90- 
per cent of metallic iron, is, therefore, obviously incorrect. I take 
this occasion to observe also that in the analyses which I have 
hitherto made of our iron ores, my chief object has been to deter-> 
mine the proportion of metallic iron which they contain. 
Paterson Mine. This is situated about three-quarters of a mile 
south from Long Mine. The general direction of the bed is the 
same as that just described, and the minerals which accompany it 
are also similar. The ore, however, is slightly different. It is 
massive, and breaks- into columnar fragments. It is not only at-- 
tracted by the magnet, but possesses magnetic polarity, approach- 
ing to the variety called naiive loadstone. In its chemical compo- 
sition it does not differ much from the preceding, except, perhaps, 
in the proportion of silica, which, being merely mixed mechani- 
cally with the oxides of iron, is of course liable to great variation^ 
This bed has not been recently worked. 
Several other beds of the magnetic ore occur in this vicinity, as 
Roberts^ Mine^ Cojiklin^s Mine, &c. ; but it would be a useless re- 
petition to give a detailed description of them. Such numerous 
and extensive deposites of this valuable mineral can not long i^e- 
main neglected as they now are, but must soon give employment to 
hundreds of individuals, and render this apparently isolated part of 
the state one of the great centres of its manufacturing operations. 
Stirling Mountain. This rises on the western side of Stirling 
pond, a beautiful sheet of water, at the outlet of which are still to 
be seen the ruins of a furnace erected previously to the revolu- 
tionary war. and in which the manufacture of iron was carried on 
at that early period with great activity. It was at this furnace 
that the iron was smelted which was used in the construction of 
the chain laid across the Hudson river at West-Point, 
The mountain just mentioned seems to be almost an entire de- 
posite of iron ore. Although the rock is sometimes observed with 
