274 Remarkable Facts, kc. 
to prevent the access of atmospheric air, and 
I am not very certain that there is not a little 
admixture.* . 
In addition to the above, I have inclosed 
two samples of copper, in two different states, 
both, however, equally pure, except that the 
one is believed to be combined with oxygen, 
and the other not. 
No. 1. is a sample taken from a furnaceful — 
of about 5 cwt. when in a melted state, and 
which had been exposed uncovered to a cur- 
rent of atmospheric air for about 2 hours be- 
fore and during the time it was melting. 
This, when poured into water, exploded most 
violently, as will be seen by the small, which 
was attempted to be granulated. 
The specimen No. 2, is a sample from the 
same copper, after the surface had been co- 
vered with charcoal, for about half an hour. 
This you will perceive, is in a very different 
state from the other, and when poured into 
water, granulated without any explosion, as 
the small bits will show. 
I remain, dear sir, 
Your obedient servant, 
SaMuUEL Lucas. 
* I found this gas to contain 86 or 87 per cent. of 
oxygen. J.D. 
