pt as streight and smooth in the sides, as is possible,
there is then a kind of double _Wedge_ to be made, and {84} fitted exactly
for it; the shape whereof is to be seen in the annexed 3. Figure.

[Illustration]

This double _Wedge_, being 12. or 13. Inches long, each piece of it, and so
made, as being placed in their due position they may make up a _Cylinder_,
but _Diagonal_-wise. The two flat sides that are contiguous, are to be
greased or oyled, that the one may slip the more easily upon the other; and
one of them, which is to be uppermost, having at the great end a hollow
_Crease_ cut into it round about, for fastening a _Cartridge_, full of
_Gunpowder_, to it with a thred, the round end of the _Wedge_ being pared
as much as the thickness of the Paper or Pastboard, that holds the Powder,
needs to make the outside thereof _even_ with the rest of the _Wedge_. This
_Wedge_ must have an Hole drilled through the longest side of it, to be
filled with _priming Powder_, for firing of the Powder in the _Cartridge_;
which needs have no more, than half a pound of Powder, though upon occasion
a greater quantity may be used, as shall be found requisite.

Then this _Wedge_, being first thrust into the Hole with the _Cartridge_,
the round side, whether the Priming-hole is, being uppermost, the other
_Wedge_ is to be thrust in, home to the due position, care being taken,
that they fit the Hole in the Rock as exactly as may be. Then the end of
the lower _Wedge_ being about an Inch longer, than that of the upper
outwardly, and flatned, priming Powder is to be laid upon it; and a piece
of burning _Match_ or _Thread_ dipt in _Brimstone_ or other such prepared
combustible Matter, fastned to it, that may burn so long before it fire the
Powder, as he, that orders it, may have time enough to retire quite out the
Pit or _Adit_, having first placed a piece of Wood or Iron so, as one end
thereof, being set against the end of the lower Wedge, and the other
against the side-wall, so as it cannot slip. Which being done, and the Man
retired, when the Powder comes to take fire, it will first drive out the
uppermost Wedge, as far as it will go, but the slaunting figure of it being
so made, as the farther it goes backward, the thicker it grows, till at the
last it can go no farther, then the {85} fire tears the Rock to get forth,
and so cracks and breaks it all about, that at one time a vast deal of it
will either be quite blown out, or so crackt a