That which is 'here to bedefcribed^ was invented by one 
of the moft Excellent Mechanh^s in the World , Monjieur du 
Svn, who lately put it in pra<Jlice himfclf in Germany, d.t the de- 
fire of the EleUor of Ment^, The manner is, as followeth. 
The Mine or Adit is to be made feven or eight foot high, 
which though it feem to make more work downwards, yet will 
be found neceflary for making the better difpatch by rendring 
the Invention more ,efFed:ual. 
There is a ToqI of Iron well-fteeled at the end , which cuts 
the Rock, (of the fliape fliewed by Fig. 2. here annexed •,)io. 
or 2.2, Inches long or morCj and fome 2 t Inches Diameter at 
the fteeled end, the reft being fomewhat more llender. The 
fteeled end is fo lliaped, as makes it moft apt to pierce the 
Rock, the Angles at that end being ftill to be made the more 
obtufe, the harder the Rock is. This T&qI is to be firft held 
by the hand, in the place, where the Hole, to be made for the 
ufe, which fliall here be fliewed, is to be placed ; that is, in the 
middle between the fides of the Rock^ that is to be cut^ bur as 
near the bottom as may be. The Te©/ being placed^ is to be 
ftruck upon with an Hammer, the heavier the better, either 
fufpended by a Shaft turning upon a Pin, or otherwife, fo as v 
one man may manage the Hammer, while another holds the 
,v Tool or fiercer. If it be hungin a Fr^^w^, or other conveni- . 
" ent way, he that manageth it hath no more to do, but to pull it 
up at firft as high as he can, and let it fall sgain by its own 
weight, the motion being fo directed, as to be fure to hit the 
Piercer right. After the ftroke of the Hammer, he that holds 
the Piercer, is to turn it a little on its point, fo that, the Edges 
or Angles at the point may all ftrike upon ^ new place : and fo 
it muft ftill be fliifted after every ftroke, by which means,fmaH 
Chipps will at every ftroke be broken off, which muft from 
time to time be taken out, as need requires. And thus the 
work muft be continued 5 tXixhQ Hole be 18. or 20. Inches 
deep, the deeper the better. This Hole being made as deep 
as is requiredj and kept as ftreight and fmooth in the fides, as is 
p-olEble, there is then a kind of double Wedge to be made, and 
fitted 
