Kuperiments on Anthracite, Plumbago, &c- 109 
Similar experiments were made with Plumbago from 
several other localities; the results of which were no wise 
different, and therefore need no further mention. 
Experiment 6th. A piece of charred mahogany, during 
its combustioi by the compound blowpipe, presented numer- 
ous small, imperfect globules, owing to the force of the flame, 
which dissipated their support before they had time to form 
or to accumulate to any considerable size; many of them 
adhered tog<ther, ramifying like flos ferri, which they resem- 
bled; they were collected by placing a dish under their sup- 
port. By the compound flux, they readily fused into a 
transparent glass. 
Experiment 7th. A quantity of lampblack was pressed 
into a mould with great force, and made to assume the form 
ef a cylinder of about 2 ofan inch in diameter, and 4 an inch 
in thickness ; it weighed seven grammes. ‘This cylinder of 
lampblack was subjected to the blowpipe. It wasted away 
gradually without forming any globules or fused matter, visi- 
ble to the naked eye or to the microseope. ‘The heat was 
equally as intense in this experiment as in all the other in- 
stances, and no condition was wanting to produce the same 
effects, except the difference of composition. After burning 
the lampblack for as long a time as was thought necessary te 
make the experiment a fair one, it was again weighed, aad 
found to have lost four grammes, ;42;, for it weighed but two 
grammes, ;°,°5. 
Five grammes of the same lampblack heated in an open 
platina crucible, left after its incineration, one centigramme 
of white ashes, equal to ;1, of the mass. 
From the analyses of the substances, used by Professér 
Silliman, from which the globules were obtained, it appears 
that they all contain foreign matter, as silex, iron, manganese, 
and some of them also alumine; that when lampblack was 
used which contained but ;1, of fixed impurities, no distinct 
globule or melted matter was formed; although the heat was 
sufficiently great, and the combustion slow enough to admit 
of the forming of globules, if their production was owing te 
the fusion of carbon, and not to extraneous matter. From my 
own experiments I always found that the more impure. the 
substance was, the more numerous and the larger were the 
globules produced. . 
All the globules from the different kinds of substances used, 
were readily fused by the compound flux, and underwent 
