56 
December 1st this great experimental philosopher put into the window 
of his chamber several islands made of cork, cut into the shape of a crown, 
and covered with blotting-paper floating in water, on which were sown credd- 
jeed. The heat of the room was 13 degrees of Reaumur. 
EXPERIMENT IX. 
One of these floating islands was placed under a glass bell containing 
twelve cubic inches of inflammable air (hydrogen air), extracted “ from 
ironf by adding to it the vitriolic acid.* 
EXPERIMENT X. 
A second was enclosed in air corrupted by breathing.'f 
* Inflammable air was the discovery of Dr. Priestley. He poured the diluted vitriolic acid upon 
iron filings, or nails, and immediately a dissolution of the iron took place, bubbles of air were engen¬ 
dered, and these being caught, were found to have peculiar characteristic marks. An animal being placed 
in this air died convulsed, a candle became extinct, and being found 15 times lighter than atmospheric 
air, it was soon employed in the formation of balloons, which in this age has, alas! realized the fable 
Icarus. 
Where were ye, Sylphs? when on the ethereal main 
Young Rosiere launch’d, and call’d your aid in vain? 
Fair mounts the light balloon, by Zephyr driven, 
Parts the thin clouds, and sails along the heaven; 
Higher and yet higher the expanding bubble flies, 
Lights with quick flash, and bursts amid the skies.— 
Headlong he rushes through the affrighted air 
With limbs distorted, and dishevel’d hair. 
Whirls round and round, the flying crowd alarms, 
And death receives him in his sable arms! 
Darwin. 
Ihis aii is called inflammable, although per se, it extinguishes flame, from this circumstance alone, 
that, when lighted, it burns when in contact with common air, and mixed with a proportion of 
oxygen, so rapid is the combustion, that it takes fire at once, and explodes with a noise resembling a 
cannon. Some inflammable air blown under soap-suds, a lighted bougie being applied to them, 
makes so loud a noise, that it seems absolutely to crack, as the common phrase is, the very drum of 
the ear.—The reader has before learnt, that light and heat alone proceed from oxygen air In the 
mode above related of procuring this air, it neither proceeds from the - ironfl or the vitriolic acid but 
from the water which has been added to the last; for no air can, in fact, be produced from concen¬ 
trated vitriolic acid poured upon iron. The theory of this experiment then is as follows. Vitriolic 
acid is sulphur and oxygen. Iron is a simple or uncompounded body. Water is a compound of 
hydrogen and oxygen. Now, when these are mixed, the oxygen of the vitriolic acid and of the water, 
having a greater affinity for the .iron than for the sulphur or the hydrogen, deserts both these, and 
unites with the iron; and the hydrogen being liberated and rarefied by the caloric produced in this 
experiment, hence it assumes an aerial form, or the condition of hydrogen air. 
I I his was a mixture of azotic air and fixed air wiiL „ cmo |] ,• r . 
, wun a small proportion of atmospheric air; for 
