350 On the Water of Tunbridge Wells. 
same stone, in a less compact or condensed state. In the centre 
of some of this hard limestone I frequently found pieces of car- 
bonaceous or coaly matter, clearly of ligneous origin, from its 
fibrous appearance; it burnt very well in the fire. In the 
middle of the stones was also found what appeared to be 
the impression of leaves, evidently proving that the stone must 
at one time have been of much softer consistence. Whenever 
the well-digger came to this soft marl, he was prevented from 
going on with his work, by an immense quantity of carbonic 
gas, which issued from it, and so powerful and continued was 
the supply of this deleterious air, that a strong fire was made 
in a kind of chimney constructed for the purpose, and which 
was connected with an air-tight shaft descending into the well ; 
yet more than a day was sometimes consumed before the gas 
could be drawn out by these means; and so abundant was at 
times the stream of gas discharged from the marl, that it 
would almost entirely extinguish the fire at the mouth of the 
shaft. Much time was thus lost, great expense incurred, 
and at times the life ofthe man endangered, for the gas would 
occasionally issue so rapidly, that it was impossible to draw 
him up sufficiently fast before he was greatly annoyed by it. 
It was therefore necessary to have recourse to another contriv- 
ance, which answered the purpose extremely well, occasioned 
no loss of time, was made at a small expense, and rendered 
the use of fire quite unnecessary. An oblong box of deal 
a foot square, was made open at the top, with a bottom to 
it, in the centre of which was a square hole, tightly fitted to an 
air-tight shaft, which projected down the well; a square flat 
piece of wood was exactly fitted to the internal surface of the 
box, but so as to slip easily up and down. It was split in the 
middle into two pieces, which were united by leather to act asa 
hinge, and to permit the two sides to flap up and down; hence 
it was denominated the flapper; to the centre of this flapper, 
between the two sides, was affixed a handle by which it was 
moved quickly up and down in the box, as in the act of churn- 
ing. Thus the pure air of the atmosphere was churned or 
pumped down into the lower part of the well through the shaft, 
