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32                 THE LABORATORY.
when they appear of an ash-colour, fing them again
into cold water; this will make them tough, otherwise
they will be brittle.
                To gild upon Iron or Steel.
   TAKE o0mmon salt, saltpitre and alum, an equal quan.
tity of each; dissolve them in as little warm water as Pos-
sible ; then filter them through whited brown paper; add
leaf gold, or rather thin beaten gold,' to it, and 'set it o
hot sand, to make it almost boiling hot; keep it in that
heat for twenty-four hours, and if the water evaporate, you
may supply it with more; but at last let it all evapo-
rate, and 'it will turn to a yellow  salt; this ulverize
put it into a glass, and cover it with strong brandy, or
spirit 6f 'wine, tw6 inches high "above the powder: then
stop 'youri'glass close, put it into a gentle warmth, and
the brandy, or spirit, will extract all the gold, and be
of a beautiful colour. With this water you may, with a
new pen or pencil, write or draw what you please upon a
sword-bla~e, knife, or any other thing made of iron or
steel, and it wIll be gilded to a high colour.     or
           .4 Ground for gilding Steel or Iron.
  TA1FE five ounces of vitriol, two ounces of gall-stne
two ounces of sal-ammoniac, one ounce 0f feather-whjte,
and a handful of common salt: beat all this together until
it is fine, and mix it well; put it into a glazed pipkin, add
to it a quart of *fater, and give it a quick boiling; then
take a knife, or any other iron that is clean, and stir it
about; if it is of a copper colour it is right, but of a red
colour it is better.
  If you have a mind to gild with this ground, put your
steel on a slow fire, and make it so hot that 'You canot
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