( 8 4 ) 
■fitted exactly for it j the fhape whereof is to be feen in the an- 
nexed 3. Figure. 
This double Wedge , being 12. or 15. Inches long, each piece 
of it, and fo made, as being placed in their due politico, they 
may make up a Cylinder , cut Diagonal-wife. The two flat 
fides, that are contiguous, are to be greafed or oyled, that the 
one may flip the more eafily upon the other ; and one of them* 
which is to be uppermoft,Chaving at the great end a hollow 
Creafdjtu t into it round about, forfaftning a Cartridge , full of 
Gunpowder , to it with a thred, the round end of the Wedge being 
pared as much, as the thicknefs of the Paper or Paftboard,that 
holds the Powder, needs to make the outfide thereof even 
with the reft of the Wedge. This Wedge muft ’have an Hole# 
drilled through the Iongeft fide of it, to be filled with priming 
Powder , for firing of the Powder in the Cartridge ; which needs 
have no more s than half a pound of Powder, though upon oc- 
cafion a greater quantity may be u fed, as (hall be found re- 
quifice. 
Then this Wedge , being firft thruft into the Hole with the Car- 
tridge, the round fide,,vyhere the Priming-hole is ? being upper- 
moft, the other WedgMi to be thruft in, home to the due pofi- 
tion, care being taken, that they fit the Hole in the Rock as 
exactly as may be. Then the end of the lower Wedge jbeing 
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 Brimjlone or other fuch pre- 
pared combuftible Matter, faftned to it, that may burn fo long, 
before it fire the Powder, as he, that orders it, 'may have time 
enough to retire quite out of the Pit or Adit, having firft pla* 
ced a piece of Wood or Iron fo, as one end thereof, being fee 
againft the end of the lower Wedge, and the other againft the 
fide-wall, io as it cannot flip. Which being done, and the Man 
retired, when the Powder comes to take fire, it will firft drive 
out the uppermoft Wedge, as far as it will go ; but the flaunt- 
ing figure of it being fo made, as the farther it goes backward, 
the thicker it grows, till at the laft it can go no farther, then the 
fire 
