Chemistry. XXvil 
our knowledge of hydrogen, phosphorus, and carbon, which 
I shall notice under this division, to which these bodies belong. 
1. Hydrogen. - My readers are aware that some years ago 
Dr. Prout showed from the specific gravity of ammoniacal gas 
that the specific gravity of pure hydrogen gas was less than had 
hitherto been supposed, and that in reality, instead of being the 
15th part of the weight of oxygen gas, it was only the 16th part 
of that weight. From the celebrity of the chemists both in this 
country and in France, who had undertaken to determine the 
specific gravity of this gas, and who had concluded it*to be to 
oxygen gas as | to 15, it is not at all surprising that this correc- 
tion of Dr. Prout made very little impression upon the chemical 
world. It would have been wonderful indeed if that had not 
been the case, and if some of those chemical understrappers who 
are unable to think with precision, or indeed to think for them- 
selves at all, had not come forward with their sneers, as if it were 
an unpardonable crime to deviate in any respect from the zpse 
divit of those individuals whom they have thought proper to set 
up as the gods of theiridolatry. All this was to be expected, and 
it took place accordingly. My readers will see, by a notice in 
the Annals of Philosophy, xii. 317, that Berzelius and Dulong 
have lately made a new set of experiments on the specific gravity 
of hydrogen gas. They have found it lighter than preceding 
experimenters, or very nearly 0-069, which is precisely the speci- 
fic gravity deduced by Dr. Prout from other considerations. This 
result has been verified in my laboratory. We found the specific 
gravity of hydrogen gas in three trials 0:06933. 
The result of the curious attempts of Thenard to add indefinite 
quantities of oxygen to the acids by means of peroxide of barytes, 
of which an account will be found in the Annals of Philosophy, 
xiii. 1, is the discovery of a deutoxide of hydrogen, or a com~- 
pound of oxygen and hydrogen, containing twice as much 
oxygen as water does. This deutoxide is a fluid less volatile 
than water, and may, therefore, be nearly freed from that liquid 
by spontaneous evaporation in an exhausted receiver containmg 
sulphuric acid. 
This deutoxide has the property of whitening all vegetable 
bodies. Probably, therefore, it is formed during the action of 
chlorine on cloth in the modern process of bleaching. | conceive 
a portion of the water to be decomposed, so that its hydrogen 
converts the chlorine into muriatic acid, while its oxygen con- 
verts another portion of the water into deutoxide of hydrogen. 
The art of bleaching then will have reached perfection when a 
cheap process is discovered of making deutoxide of hydrogen on 
a large scale. 
2. Carburetted Hydrogen Gas.—Mr. Faraday has pointed out 
what he considers as a mistake in the generally received opinions 
respecting carburetted hydrogen gas. It is generally believed, 
he says, that chlorine has no action on this gas, whereas he finds 
