_Tuch_ (Vol. vii., p. 82.).--ALPHAGE suggests that the "touchstone" had its
name because "a musical sound may be produced by touching it {188} sharply
with a stick." I think this is an error, and that it owes its name to its
use in the assay of gold and silver. We find this application of it
described in a work (now scarce) published in 1677, under the title of _A
Touchstone for Gold and Silver Wares_. The author, after describing the
qualities of a good touchstone, observes (p. 36.):
"The way to make a true touch on the touch-stone is thus: When your
touch-stone is very clean ... your silver being filed ... rub it
steadily, and very hard, on the stone ... until the place of the stone
whereon you rub be like the metal itself ... wet all the toucht places
with your tongue, and it will show itself in its own countenance."
And that the touchstone was used in this connexion at a much earlier period
is obvious from the language of the ancient statutes. The 28 Edward I.,
stat. 3. cap. 20., requires all gold and silver wares to be "of good and
true allay, that is to say, gold of a certain _touch_." And the word occurs
in the same sense in other statutes.