shown you a way by means of the Tincture of _Lignum Nephriticum_, or of
Syrrup of Violets, to discover whether a propounded Salt be Acid or not,
yet you can thereby only find in general that such and such Salts belong
not to the Tribe of Acids, but cannot determine whether they belong to the
Tribe of Urinous Salts (under which for distinction sake I comprehend all
those Volatile Salts of Animal or other Substances that are contrary to
Acids) or to that of Alcalies. For as well the one as the other of these
Salino-Sulphurous Salts will restore the Cæruleous Colour to the Tincture
of _Lignum Nephriticum_, and turn that of Syrrup of Violets into Green.
Wherefore this XL. Experiment does opportunely supply the deficiency of
those. For being sollicitous to find out some ready wayes of discriminating
the Tribes of Chymical Salts, I found that all those I thought fit to make
Tryal of, would, if they were of a Lixiviate Nature, make with Sublimate
dissolv'd in Fair Water an _Orange Tawny_ Precipitate; whereas if they were
of an Urinous Nature the Precipitate would be _White_ and Milky. So that
having alwayes by me some Syrrup of Violets and some Solution of Sublimate,
I can by the help of the first of those Liquors discover in a trice,
whether the propounded Salt or Saline Body be of an Acid Nature or no, if
it be I need (you know) inquire no further; but if it be not, I can very
easily, and as readily distinguish between the other two kinds of Salts, by
the White or Orange-Colour that is immediately produc'd, by letting fall a
few Drops or Grains of the Salt to be examin'd, into a spoonfull of the
cleer Solution of Sublimate. For Example, it has been suppos'd by some
eminently Learned, That when Sal Armoniack being mingled with an Alcaly is
forc'd from it by the Fire in close Vessels, the Volatile Salt that will
thereby be obtain'd (if the Operation be skilfully perform'd,) is but a
more fine and subtile sort of Sal Armoniack, which, 'tis presum'd, this
Operation do's but more exquisitely purifie, than common Solutions,
Filtrations, and Coagulations. But this Opinion may be easily shown to be
Erroneous, as by other Arguments, so particularly by the lately deliver'd