6o 
Mr. Davy’s Experiments on 
water, globules of gas were slowly liberated, and the effect 
continued for nearly an hour ; so that there is great reason to 
believe, that the silex had been either entirely or partially 
deoxygenated, and was slowly reproduced by the action of the 
water, assisted by the slight attraction of the acid for the earth. 
When the potassium was in the quantity of six grains, and 
the silex of four grains, a part of the result inflamed spon- 
taneously as it was taken out of the tube, though the tube 
was quite cool, and left as the result of its combustion, alkali 
and silex. The part which did not inflame, was similar in 
character to the matter which has been just described, it did 
not act upon water, but effervesced with muriatic acid. 
Potassium in acting upon alumine and glucine, produced 
more hydrogene than could be ascribed to the moisture 
present in the crust of potash ; from which it seems probable 
that even after ignition, water adheres to these earths. 
The results of the action of the potassium, were pyrophoric 
substances of a dark gray colour, which burnt, throwing off 
brilliant sparks,* and leaving behind alkali and earth, and 
which hissed violently when thrown upon water, decomposing 
it with great violence. I examined the products in two expe- 
riments, one on alumine, and one on glucine, in which naphtha 
was introduced into the platina tube, to prevent combustion ; 
the masses were very friable, and presented small metallic 
particles, which were as soft as potassium, but so small that 
they could not be separated, so as to be more minutely exa- 
mined ; they melted in boiling naphtha. Either a part of the 
* The pyrophorus from alum, which I have supposed in the last Bakerian lecture, 
to be a compound of potassium, sulphur, and charcoal, probably contains this sub» 
stance likewise. 
