Zinc } { Zinc.
Salifiable simple Earthy Substances.
_New Names._ _Correspondent old Names._
Lime {Chalk, calcareous earth.
{Quicklime.
Magnesia {Magnesia, base of Epsom salt.
{Calcined or caustic magnesia.
Barytes Barytes, or heavy earth.
Argill Clay, earth of alum.
Silex Siliceous or vitrifiable earth.
SECT. I.--_Observations upon the Table of Simple Substances._
The principle object of chemical experiments is to decompose natural
bodies, so as separately to examine the different substances which enter
into their composition. By consulting chemical systems, it will be found
that this science of chemical analysis has made rapid progress in our
own times. Formerly oil and salt were considered as elements of bodies,
whereas later observation and experiment have shown that all salts,
instead of being simple, are composed of an acid united to a base. The
bounds of analysis have been greatly enlarged by modern discoveries[36];
the acids are shown to be composed of oxygen, as an acidifying principle
common to all, united in each to a particular base. I have proved what
Mr Haffenfratz had before advanced, that these radicals of the acids
are not all simple elements, many of them being, like the oily
principle, composed of hydrogen and charcoal. Even the bases of neutral
salts have been proved by Mr Berthollet to be compounds, as he has shown
that ammoniac is composed of azote and hydrogen.
Thus, as chemistry advances towards perfection, by dividing and
subdividing, it is impossible to say where it is to end; and these
things we at present suppose simple may soon be found quite otherwise.
All we dare venture to affirm of any substance is, that it must be
considered as simple in the present state of our knowledge, and so far
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