F. The _Dore_, by which the _Grate_ and _Cradle_ is let in, which is {82} to be set 8. or 10. foot higher than the Hole D. and the _Shutter_ made of Iron, or Wood that will not shrink, that it may shut very close, this _Dore_ being made large enough to receive the _Cradle_ with ease. G. The _Grate_ or _Cradle_, which is narrower below than above, that the Ashes may the more easily fall, and the Air excite the Fire; the bottom being barred as the sides. H. The _Border_ or _Ledge_ of the _Cradle_, that rests upon the _Ledge_ C. I. Four _Chains_ of _Iron_ fastned to the four corners of the _Cradle_, for taking of it up, and letting of it down. K. The _Chain_ of _Iron_, to which the other are fastned. L. The _Pulley_ of _Iron_ or _Brass_, through which the _Chain_ passeth. M. A _Hook_, on which the end of the _Chain_ is fastned by a _Ring_, the _Hook_ fixed being placed in the side of the Dore. N. A _Barr_ of _Iron_ in the Walls, to which the _Pulley_ is fastned. The higher the _Shaft_ of the Chimney is, the Fire draws the Air the better. And this Invention may be made use of in the _Pits_ or _Shafts_, that are _Perpendicular_, or any wise inclining towards it, when there is want of fresh Air at the bottom thereof, or any molestation by unwholsom Fumes or Vapors: * * * * * _A way to break _easily_ and _speedily_ the hardest _Rocks_, communicated by the same Person, as he received it from Monsieur _Du Son_, the Inventor._ [Illustration] Though the invention of breaking with ease, and dispatch, hard Rocks, may be useful on several occasions, the benefit is incomparably great, that may thereby accrue to those, who have _Adits_ or Passages to cut through hard _Rocks_, for making passage for Water to run out by, in _Mines_ of _Lead_, _Tin_, or any other whatsoever; these _Adits_ appearing to be the surest, cheapest, and most advantagious way imaginable, for draining of the same. {83} That which is here to be described, was invented by one of the most Excellent _Mechanicks_ in the World, _Monsieur du Son_, who lately put it in practice himself in _Germany_, at the desire of the _Elector_ of _Mentz_. The manner is, as followeth. The _Mine_ or _Adit_ is to be made seven or eight foot high, which though it seem to make more work downwards, yet will be found necessary for making the better dispatch by rendring the Invention more effectual.