Experiments upon Diamond, Anthracite and Plumbago. 353 
of carbon. If the former be true, it proves that no existing 
analysis of plumbago can be correct, and would still leave 
the remarkable white fume, so abundantly exhaled between 
the poles of the deflagrator, and so rapidly transferred from 
‘the copper to the zine pole, entirely unaccounted for. 
would add, that for the mere fusion of plumbago, the blow- 
pipe is much preferable to the deflagrator, but a variety of 
interesting phenomena in relation to both plumbago and 
charcoal are exhibited by the latter and not by the former. 
Hoping that if these subjects have not already engaged 
your attention, they will speedily do so, I remain 7 dear 
Be as ever, your friend and servant. 
B. SILLIMAN. 
Postscript, April 18. Fusion or ANTHRACITE. 
The anthracite of Rhode-Island is thought, to be very 
pure. Dr, William Meade, (See Bruce’s Journal; pa. 36) 
estimates its proportion of carbon at ninety-four ‘per oe 
This anthracite I have just succeeded in melting by the 
compound blow-pipe. It gives large brilliant black globules, 
not attractable by the magnet, but in other respects not to 
be distinguished from the dark -hitailes of melted plumbago. 
The experiment was entirely successful in every trial, 
-and the great number of the globules and their evident flow 
from, and connexion with, the entire mass, permitted no 
doubt as to their being really the melted anthracite 
The Kilkenny coal gave only white and transparent glob- 
ules; but it seems rather difficult to impute this to impuri- 
ties, since this oe is stated to contain ninety-seven 
per cent. of ca 
[ have Aine a diane this afternoon to the solar fo- 
cus in a jar of pure oxygen gas, but observed no signs of fu- 
sion, nor indeed did I expect it, but I wished to compare 
this old ie ar biepea with those related above 
The diamond is now the only substance whink has not 
been perteatly melted. 
I inserted a piece of plumbago into a cavity in quick lime, 
and succeeded in melting it down by the blow- pipe into two 
or three large globules, adhering into one mass, and occupy- 
ing the cavity in the lime; these globules were limpid, and 
nothing remained of the original appearance of the plumba- 
go except a few black poinis. 
Vol. VI.—Na. 2. 
