cur, when fuch Adits are wrought or driven inward upon a 
Level, or near it, 20, 30, or 40. fathom, moreorlefs: Afwe! 
becaufe of the expence of money, as of time aifo 5 in the 'Ordi- 
nary way of preventing or remedying thofe inconveniences* 
which is, by letting down Jljafts from the^y(as Miners fpeak) 
to mee& wifctthb Adk j by which means the Air hath liberty 
to play through the whole work , and fo takes away bad va- 
pours and furnifhes good Air for Refpiration. The Expence 
of which fijafts, in regard of their vaft depth , hardnefs of the 
Rock, drawing of water Gfodoth fometimes equafyea exceed 
the ordinary charge of the whole Adit. 
Amongft the txpedients that have been devifed to remedy 
this, there is one pradifed in the Coal-mines , near the Town of 
Liege (or Luyc\j thatfeems preferable to all others for Effi- 
cacy s Eafc, and Cheapnefs ; the defeription whereof fol- 
io weth. 
^ At the month or entry of the Adit there is a flrudure raifed 
or Brie ^ 0 like a Chimney , fome 28. or 30. foot high in all : at 
the bottom, two oppofite hides are (or may be) fome A- foot 
broad; and the other two, 5. foot : the wall *\Bric\ thick. 
At the lower part of it, is a hole, fome 9. or 1 o. inches fquare, 
for taking out of the Afhes , which when it is done, this A 111 - 
hole is immediately flopt fo clofe, as Air cannot poflibly get 
in at any part of it. Then, fome 9. foot above ground or 
more, there is on that fide, that is next to the Adit or Pit, a 
fqnare hole of Tor 9. inches everyway, by which the Air 
enters to make the Fire burn ; Into this hole there is fixed a 
Iquare Tube or Pipe of Wood, whereof the joints and Chinks 
are fo flopt with Parchment pafled or glewed upon them, 
that the Air can no where get in to the Pipe but at the end : 
And this Pipe is flill fengthned , as th & Adit or Pit advanced!, 
by fitting the new Pipes fo, as one end is alwaies thruft into- 
the other, and the Joints and Chinks flill carefully cemented 
and flopt as before'. So the Pipe or Tube beingflill carried 
on, as near as is neceffary, to the wall or place , where frefh 
Air is requifke 3 the Fire within the Chimney doth flill attrad 
