198 New Locality of Cobalt. 
the carburetted hydrogen gas, which issues from the foot 
of a hill near the stage road, one mile west of Vernon vil- 
Jage, undoubtedly proceeds from crevices in the red rock, 
which forms the floor of the salt springs. It burns  brill- 
iantly, and is considered as strongly indicating the exist- 
ence of coal beneath the red rock. 
The few facts here enumerated I give from personal 
examination, made since [ have been in the employment 
of the Hon. Stephen Van Rensselaer. 
AMOS EATON. 
Troy, N. Y., March 20, 1824. Ui 
9. Ignition of Platinum. 
To the Editor. 
Dartmouth College, April 29, 1824. 
Dear Sip, | 
I have been engaged in repeating the experiments of 
Doberciner and others on the ignition of finely divided pla- 
tinum. 
I find that when the vapour of ether or of alcohol is 
made to pass on to platinum sponge, in a manner similar to 
that in which a jet of hydrogen is thrown upon it, that the 
platinum becomes brilliantly ignited; but it requires for 
this eflecta slightly elevated temperature, yet. so low that 
the platina sponge may be held with great ease in the hand, 
before exposure to the vapour. I have not noticed in 
any journal that this effect has been observed with the 
vapour.of fluids thrown upon spongy platina.* 
if 
0. New Locality of Cobalt. 
Beautiful crystals of arsenical cobalt in octahedra, deeply 
truncated, have been found at Franconia, N. H. J have 
some specimens already packed with other minerals which 
I shall forward to you very soon. 
With great esteem yours, Ss. F. DANA. 
*T have seen none later than No. 32 of Brande. 
