That which is hereto be dcfcribed, was invented by one 
of the moft Excellent Mechanie.ks in the World, Monfieur du 
Son , who lately put it in practice himfel'f in . Germany 9 ai the de- 
fine of the Elector of Ment\. The manner is, as folio weth. 
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 neceftary for making the better difpatch by rendring 
the Invention more effectual 
There is a Tool of Iron well-fteeled at the end , which cuts 
the Rock, (of the fhape fhewed by Fig, 2. here annexed ,)2o. 
or 22. Inches long or mere, and fome 2 f Inches Diameter at 
the fteeled end, the reft being fomewhat more {lender. The 
fteeled end is fo fhaped, 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 Tool is to be firft held 
by the hand, in the place, where the Hole, to be made for the 
yfe, which fhall here be ihewed, is to be placed ; that is, in the 
middle between the fides of the Rock, that is to be cot, but as 
near the bottom as may be. The Tool being placed, is to be 
ftrack upon with an Hammer, .the heavier the better, either 
fufpended by a Shaft turning upon a Pirn, or other-wife, fo as 
one man may manage the Hammer, while another holds the 
Tool or fiercer. If it be hung in a Frame , 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 again by its own 
weight, the motion being fo directed, as to be fnre 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 ail ftrike upon a new place : and fo 
it moft ftill be (hifted after every ftroke, by which means, fmaJl 
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 , till the Hole be 18, or 20; Inches 
deep, the deeper the better. This Hole being made as deep 
ired, and kept 
there is then a 
as ftreight and fmooth in the fides, as is 
kind, of double Wed^e ro be made, ami 
