490 
Book II. 
Water ab 
sorbs air 
And oxy 
gen gas; 
Its action 
on bodies. 
OXIDES. 
mixed : It must therefore have contained hydrogen. 
When an electric spark was passed through the gas 
thus produced from water, the gas disappeared, being 
no doubt converted into water *. 
Such are the proofs by which the component parts of 
water have been ascertained. If we consider them at 
tentively, and compare them with a vast number of 
other chemical phenomena, all of which tend to confirm 
and establish them, we must allow, 1 think, that scarce 
ly any physical fact whatever can be produced, which is 
supported by more complete evidence. There are in 
deed some galvanic phenomena which scarcely seem 
compatible with it ; but the nature of this singular 
power is still too imperfectly understood to warrant 
even a conjecture concerning it. 
Water has the property of absorbing atmospheric 
air ; and it always contains a portion of it when it has 
been exposed to the atmosphere. The greater part of 
this air is driven off by boiling : but, from the experi 
ments of Dr Priestley, it appears, that the whole of it 
is not separated; nor can it be completely separated by 
any method at present known. Water owes its agree 
able taste to the presence of air ; hence the insipidity 
of boiled water. 
Water absorbs oxygen gas in preference to air, and 
nearly in the same proportion, as was first ascertained 
by Scheele. 
Water is not altered by being made to pass through 
a red hot porcelain tube. 
It has no action on any of the simple combustibles 
while cold ; nor does it combine with any of them. It 
k Nicholsons Journal, i. 242.