72 Mr. Davy’s Lecture on some new analytical Researches 
flame seemed to issue of a most brilliant purple, and formed* 
as it were, a conducting chain of light of nearly an inch in 
length, at the same time that elastic matter was rapidly form- 
ed, some of which was permanent. After many unsuccessful 
trials, I at length succeeded in collecting the quantity of elastic 
fluid given out by half a grain of charcoal ; the process had 
been continued nearly half an hour. The quantity of gas 
amounted to nearly an eighth of a cubical inch ; it was inflamma- 
ble by the electric spark with oxygene gas, and four measures 
of it absorbed three measures of oxygene, and produced one 
measure and a half of carbonic acid. The charcoal in this ex- 
periment had become harder at the point, and its lustre, where 
it had been heated to whiteness, approached to that of plum- 
bago. 
I heated two grains of potassium together with two grains 
of charcoal, for five minutes ; and to estimate the effects of 
the metallic oxides and potash in the green glass tube, I made 
a comparative experiment, as in the case of plumbago ; but 
there was no proof of any oxygene being furnished to the 
potassium from the charcoal in the process, for the compound 
acted upon water with great energy, and produced a quantity 
of inflammable gas, only inferior by one twelfth to that pro- 
duced by the potassium, which had not been combined with 
charcoal, and which gave the same diminution by detonation 
with oxygene ; and the slight difference may be well as- 
cribed to the influence of foreign matters in the charcoal. 
There was no ignition in the process, and no gas was 
evolved. 
The compound produced in other experiments of this kind 
was examined. It is a conductor of electricity, is of a dense 
