96 New Outlines of Chemical Philosophy. 
¢ From this experiment, therefore, conducted in this manner, 
it might be concluded that water consists of hydrogen only, with- 
out any oxygen, 
<¢ But according to my experiment with ferra ponderosa aérata, 
it may be proved to consist of oxygen only. For when steam 
is sent over this substance in a red heat, nothing but the purest 
fixed air is produced; and yet the whole of any quantity of wa- 
ter may be expended in that production. As water is not said 
to contain any carbon, this must be supplied by the ferra pon- 
derosa, and all the oxygen by the water. For ‘according to the 
theory fixed air consists of 28 parts of carbon, and 72 of oxygen. 
« These experiments favour my hypothesis, that water is the 
basis of all kinds of air, and therefore, that without it no kind of 
air can be produced.’’—Dr. Priestley on Phlogiston, page 51.— 
Northumberland, Feb. 1, 1800. 
“In my opinion,’ ’ saysDr. Priestley, ‘and that of long standing, 
that black calx of iron called finery cinder contains uo oxygen, 
but only water. 
«© Now what I maintain is, that when finery cinder is revived 
(which, however, is not done without the introduction of phlo- 
giston*,) nothing but water is separated from it. 
sos Northumberland; America, Noy. 5, 1802.”—Philosophical 
Journal, vol. iv. p. 66. 
Experiments which tend to confirm the truth of Dr. Priest- 
ley’s have lately been published by Sir Humphry Davy f. 
<<] have mentioned, page 172,” says Sir H. Davy, “that in the 
électrization of a globule of mercury in water, oxygen appears 
to be combined with the metal, and yet no hydrogen evolved. 
I have made a number of experiments on this subject, and have 
ascertained that, in the process described, oxide is formed, 
without any apparent compensation, in the production of inflam- 
mable matter; nor was I able to detect any combinaticn into 
which the hydrogen could have entered ; so that these experi- 
ments as they now stand, would induce the belief that water is 
the ponderable basis of both oxygen and hydrogen, and that 
these two forms of matter owe their peculiar properties either to 
the agency of imponderable substances, or to peculiar arrange- 
ments of the particles of thesame matter. But such a formidable 
conclusion as this must not be hastily adopted; for in all other 
cases oxygen and hydrogen appear as perfectly inconvertible 
* Scheele says that “ phlogiston is a true e/ement and a simple princi- 
ple.”—Scheele on Air and Fire, p. 103. 
For a more particular account of phlogiston, see Philosophical Magazine, 
tol. xlvi. p. 430. 
t From Davy’s Elements of Chem. Phil. p. 485. 
substances, 
