1889. ] NEW YORK ACADEMY OF SCIENCES. 149 
mined; but all the tin brought from the island of Banca, from 
the Malay peninsula, and from Australia, is obtained by the 
working-over of gravel. The granite containing it has been 
largely carried away, and what remains is decomposed, so that 
the tin is obtained by washing. There, too, labor is very cheap. 
The Chinese do well at placer mining, where Americans would 
starve. 
I do not know whether we can ascertain how large a quantity 
of material has been taken from King’s Mountain by erosion ; 
but further north in the Alleghanies the rocks have been very 
largely removed. Where erosion has been less active, the rock 
has been rotted down to a depth of thirty to sixty feet, just as 
Prof. Agassiz tells us that in Brazil the rocks are sometimes 
decomposed to the depth of 150 feet. If any such decay has af- 
fected the tin-bearing rocks of North Carolina, the ore could be 
cheaply worked-out, if sufficient water were to be had. 
I think we owe a great debt to Mr. FurMAN for his discovery, 
and for the very lucid description he has given us. That it is 
a true tin deposit there can be no question, but just how much 
it will be worth to us zs a question. 
This is a very different affair from the so-called tin-stone that 
was brought here from Virginia three or four years ago. A 
hundred pounds of it were sent to me, and we had it analyzed in 
the School of Mines, but never got any tin from it. Other par- 
ties have claimed that they found in it 20 per cent of the metal. 
I have seen certificates from those who profess to be assayers, 
claiming large returns of tin from this rock. I do not believe 
that there is any tin init at all. But this is a real tin deposit, 
and it may be that it will prove a productive one. I would like 
to ask about the water there. 
Dr. Lepoux.—There is plenty of water in the creek 100 feet 
below, that being the water-shed where the vein is. 
THE PRESIDENT.—The lack of water may be a difficulty. I 
should like it if we could get there a head of 500 feet of water, 
as they do in California, where they cut down gravel banks 100 
feet high and make a handsome profit from gravel, of which a 
cubic yard will yield but ten cents, 
In this connection, I have to show you a very different style 
