326 Manufacture of Suiphat of Iron. 
Arr. XII.— Some account of the pes eras mines and mani- 
factory in Strafford, Vt. ; r. Joun Locke. 
THE mine is situated about twelve miles from Dartmouth 
College, and about five miles from Thetford, Vt. It is near 
the summit of a hill which rises probably two or three 
hundred feet above the bed of the streams in the vallies 
it 
The ein § Which it occurs is mica slate, the strata of 
which, are very highly inclined to the horizon, and present 
their ridges above the surface in various parts of the 
hill, particularly at its summit. ere are occasionally 
veins of quartz in the slate. The rocks for several miles 
around are, as far as I observed, principally mica slate. 
There are no particular indications of iron at any consider- 
ble distance from the mass of the mine, but the transition 
from the slate to the pyritic ore is eee The mine has 
sepa cians up the hill, about twenty rods in 
lengt in breadth. | The of ore has been traced near 
alfa benesy running pretty much in the direction of the stra- 
ta of the slate. 
The ore consists of an aggregate se quartz and undecom- 
posed pyrites in small grains. In its granular aggregation, 
the ore resembles the quartz and Seldspat in fine grained 
rig The pyrites constitutes the greater proportion. 
any specimens contain abundance of needle shaped erys- 
tals of schorl. Its fracture possesses a metallic lustre, and 
of it bs otras colour to pale brass, from which it 
varies to steel 
- ore is ver compact and is obtained for manufactur- 
ing by drilling and blowing. In manufacturing i it into cop 
peras it goes through t 
lixiviation and e oration, each of which constitutes a dis- 
tinct c several years the manufacturers effect- 
De decom ecompostion in ate following manner: the ore was 
brok ragments of a foot or less in diameter, and 
futaped ee inclined scaffolds erected and floored with 
lank for the purpose. Thus exposed to the action of air 
— moisture it very gradually decomposes at the surface. 
e same mass of ore a solution was obtained, 
year fee tee. either by the rains or by the application of 
water | means. The solution was received from 
the inclined vat romp in plank cisterns. 
