a3 Hot Blast in the Smelting of Lead. 
which it is agitated by cam C. The diggings from the crusher 
being thrown into this sieve and the lever let into the cam, the 
contents of the sieve immediately arrange themselves in strata 
according to their relative gravities; first, clean gangue on the 
surface, next, ‘middlings,’ being spar with particles of ore attach- 
ed, (these are thrown back to be recrushed,) next, lead ore, the 
surface of which has more or less gangue adhering, the lower 
strata nearly pure. The ore as smelted, contains from five to ten 
per cent. of calc spar adhering and scattered through it. The 
mineral which passes through the sieve is taken from the vat 
and washed in a stream of water upon an inclined table, both so 
graduated that the ore remains near the stream and the impuri- 
ties may be carried off. 
The Rossie Lead Mines.—Of the bubbles of ’36 and ’37, per- 
haps none was more wnmercifully inflated than that of the Rossie 
lead stock. It is unfortunate for the mining interest in that very in- 
teresting and promising region, that this remarkable mine should 
have become by a ten years’ lease the property of a company, 
and thus made at once the victim of speculation. In taking out 
the ore for the first one hundred feet in depth, little expense was 
necessary, and the product and profits were large. At the depth 
now attained, say from one hundred and seventy five to two hun- 
dred feet, permanent and adequate machinery and good engineer-. 
ing are required, having reference to working the mine for a long. 
series of years. The investments necessary for this can hardly 
be looked for until the fee of the land and the rights to the mine 
are owned by the same person or company. ‘The amount of lead 
smelted from these mines in 1837 and 1838, was 4,137,871 Ibs. ; 
in 1839, about 1,200,000 lbs. ; in 1840, about 400,000 Ibs. 
‘The primitive rock, (hornblende gneiss,) in which this mine 
lies, has but few fissures through which water is discharged, and 
hence is easily kept free. It is already wrought one hundred 
feet below Indian River, which flows some eighty rods distant. 
Whatever may be the difficulties of the present unfortunate tenure 
of | this valuable mine, there is little doubt that it will eventually 
Oeeenls wrought and yield a uniform and adequate return. 
1e VE perpendicularly ; the quantity of ore ina given 
ab ut the same, and in all probability is inexhaustible. 
ae NE SME ok a 
et 
