being formed during the process by which it is obtained,
and was consequently supposed to differ according to the nature of the
acid employed in separating it from the soda; but it is now universally
acknowledged that it is identically the same acid, in whatever way
procured, provided it be properly purified from mixture of other acids,
by warning, and by repeated solution and cristallization. It is soluble
both in water and alkohol, and has the property of communicating a green
colour to the flame of that spirit. This circumstance led to a suspicion
of its containing copper, which is not confirmed by any decisive
experiment. On the contrary, if it contain any of that metal, it must
only be considered as an accidental mixture. It combines with the
salifiable bases in the humid way; and though, in this manner, it is
incapable of dissolving any of the metals directly, this combination is
readily affected by compound affinity.

The Table presents its combinations in the order of affinity in the
humid way; but there is a considerable change in the order when we
operate via sicca; for, in that case, argill, though the last in our
list, must be placed immediately after soda.

The boracic radical is hitherto unknown; no experiments having as yet
been able to decompose the acid; We conclude, from analogy with the
other acids, that oxygen exists in its composition as the acidifying
principle.

TABLE _of the Combinations of Arseniac Acid, with the Salifiable Bases,
in the Order of Affinity._

_Bases._ _Neutral Salts._

Lime Arseniat of lime.
Barytes barytes.
Magnesia magnesia.
Potash potash.
Soda soda.
Ammoniac ammoniac.
Oxyd of
zinc zinc.
manganese manganese.
iron iron.
lead lead.
tin tin.
cobalt cobalt.
copper copper.
nickel nickel.
bismuth bismuth.
mercury mercury.
antimony antimony.
silver silver.
gold gold.
platina platina.
Argill argill.

_Note._--This order of salts was entirely unknown to the antient
chemists. Mr Macquer, in 1746, discovered the