559 
Combustion of the Diamond, 
Florentine Museum ; and in the last by that of Sig. Morrichini 
and Barlocci, Professors of the College Sapienza at Rome. 
In the very first trials on the combustion of the diamond, I 
ascertained a circumstance that I believe has not been noticed 
before ; namely, that the diamond, when strongly ignited by 
the lens in a thin capsule of platinum perforated with many 
orifices, so as to admit a free circulation of air, continues to burn 
in oxygene gas after being withdrawn from the focus. The 
light it afibrds is steady, and of so brilliant a red, as to be 
visible in the brightest sunshine ; and the heat produced is so 
great, that in one experiment, in which three fragments of 
diamonds weighing i.Szj, grain only were burnt, a fine wire 
of platinum used for attaching them to the tray was fused, and 
that some time after the diamonds were removed out of the 
focus. 
_ The knowledge of this circumstance enabled me to adopt a 
very simple apparatus and mode of operation in my researches, 
and to complete, in a few minutes, experiments which have 
been supposed to require the presence of a bright sunshine 
for many hours. 
My apparatus consisted of clear glass globes of the capacity 
of from fourteen to forty cubical inches, having single aper- 
tures to which stop-cocks were attached; a small hollow 
cylinder of platinum, which I use in experiments with the blow 
pipe, was attached to one end of the stop-cock, and was mounted 
with a little perforated capsule of platinum for containing the 
diamond. When the experiment was to be made, the globe 
containing the capsule and the substance to be burned was 
exhausted by an excellent air pump, and pure oxygene gas, 
made from hyperoxyinuriate of potassa, admitted. The globe 
4 C 9 
