108  Kzaperiments on Anthracite, Plumbago, &c. 
little change when it was not used; although the heat was, in 
this case, of longer conti-uance. atter similar to the im- 
purities discovered in the substances used, was detected in 
em, ‘ 3 : 
‘From these facts it would appear, that the globules pro- 
duced from the combustible substances operated upon, di 
not arise from the fusion of their carbon, since they can 
otherwise be accounted for; particularly as no experiment 
has been made which unequivocally leads to that conclusion. 
The experiment upon which Professor Silliman relies, as a 
proof of the globules being fused carbon, is one which is not 
satisfactory to me ; if it had been, it would have given me 
great pleasure ; for no one, I trust, feels more. interested in 
the scientific prosperity. of his country than [I do; and if 
Professor Silliman were right, it would indeed be a triumph 
for America. adel 
e experiment just alluded to, (see vol. vi. p- 1347, 
Journal of Science,) is the heating some of the coloured 
globules in oxygen gas by the solar rays, with a lens. The 
following is an extract from the papers. 2 
thumb and finger, in the 
were in the focus for 
That this experiment is equivocal] appears certain, a8 par- 
ticles of the support might have been attached to~the 
globules ; for, from my own observations, I found that in a 
great number of instances, some of the white globules at the 
oint of junction with their support, had small dark particles 
attached to them, and when the surface from which they 
were detached was magnetic, they were attracted by the 
magnet when it was presented to those parts; I could not 
disengage those particles by rubbing the globules with my 
fingers one against another. It is very evident that, as the 
globules underwent no change, (unless a reduction of 
volume, which is not mentioned) as the description clearly. 
shows, the carbonic acid obtained. might have been produced 
hy the combustion of portions of the support adhering to 
= 
them externally, and penetrating them to a certain extent. 
