species of metals, but even according to the various degrees of
oxygenation in the same metal. Hence we are under the necessity of
adding two epithets to each oxyd, one of which indicates the metal
_oxydated_[15], while the other indicates the peculiar colour of the
oxyd. Thus, we have the black oxyd of iron, the red oxyd of iron, and
the yellow oxyd of iron; which expressions respectively answer to the
old unmeaning terms of martial ethiops, colcothar, and rust of iron, or
ochre. We have likewise the gray, yellow, and red oxyds of lead, which
answer to the equally false or insignificant terms, ashes of lead,
massicot, and minium.
These denominations sometimes become rather long, especially when we
mean to indicate whether the metal has been oxydated in the air, by
detonation with nitre, or by means of acids; but then they always convey
just and accurate ideas of the corresponding object which we wish to
express by their use. All this will be rendered perfectly clear and
distinct by means of the tables which are added to this work.
FOOTNOTES:
[15] Here we see the word oxyd converted into the verb _to oxydate_,
_oxydated_, _oxydating_, after the same manner with the derivation of
the verb _to oxygenate_, _oxygenated_, _oxygenating_, from the word
_oxygen_. I am not clear of the absolute necessity of this second verb
here first introduced, but think, in a work of this nature, that it is
the duty of the translator to neglect every other consideration for the
sake of strict fidelity to the ideas of his author.--E.
CHAP. VIII.
_Of the Radical Principle of Water, and of its Decomposition by Charcoal
and Iron._
Until very lately, water has always been thought a simple substance,
insomuch that the older chemists considered it as an element. Such it
undoubtedly was to them, as they were unable to decompose it; or, at
73