_To cut a Glass, a Looking-glass, or even a Piece of Crystal, let it
be ever so thick, without the Help of a Diamond, in the same Shape as
the Mark of the Drawing made on it with Ink._
This remarkable operation unites utility with amusement. For being in
the country, or in a place where there is no glazier nor glassman to be
had, the following means will answer the purpose without their help.
Take a bit of a walnut-tree, about the thickness of a candle, and cut
one of its ends to a point; put that end in the fire, and let it burn
till it is quite red. While the stick is burning, draw on the glass or
crystal, with ink, the design or outline of the form in which you mean
to cut it out. Then take a file or a bit of glass and scratch a little
the place where you mean to begin your section; then take the wood red
hot from the fire, and lay the point of it about the twentieth part
of an inch, or thickness of a guinea, from the marked place; taking
care to blow always on that point in order to keep it red; follow the
drawing traced on the glass, leaving, as before, about the twentieth
part of an inch interval every time that you present your piece of
wood, which you must take care to blow often.
After having followed exactly the outlines of your drawing, to separate
the two pieces thus cut, you need only pull them up and down, and they
will divide.