46 
SHOUT NOTES ON PUOEE3SIONAL SUBJECTS. 
descent by a third man, who, standing on one side, forces it down at each descent. 
On the clamp reaching the level of the ground, the monkey is raised while the 
clamp is unscrewed, and raised a height of 18 in. or 2 ft. up the tube, and again 
screwed up. The monkey is then lowered on to the clamp, and the pulleys are 
fastened higher up the tube. 
The tube during its descent should be occasionally turned round in the ground, 
so that the position of the angles of the edges of the point may continually be 
altered. The same man who does this should pay particular attention to the clamp, 
to see that it does not move on the tube, tightening up the bolts at the first appear¬ 
ance of any slipping. 
. When the tube is driven so far into the ground that its upper end is not suffi¬ 
ciently high to carry the pulleys, a piece of pipe about 6 ft. long (Fig. 2), having a 
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Tig. 2. 4 
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piece of tube 3 ft. long, of the same exterior diameter (1J in.) as its internal 
diameter, brazed for a length of 18 in. into one end, and consequently projecting 
a length of 18 in., is placed in the upper end of the tube, and the pulleys clamped 
into it at a convenient height. The driving is continued until the first tube is 
driven all but two or three inches, when the clamp, monkey, &c. are removed, and an 
additional length screwed in by means of a collar. This length is driven as before, 
care being taken to turn round the tube in the boring to tighten up the joints, 
which become loosened by the jarring of the monkey. 
Before screwing in an additional length of pipe, the well is sounded by means of 
a small lead line, to ascertain the depth of water or character of rubbish which 
penetrates through the holes in driving. 
As soon as it appears that the well is driven deep enough, a pump is screwed in 
at the top, and the water drawn up. It usually happens that the water is at first 
turbid, but after a short time, as the chamber at the bottom of the well becomes 
enlarged, this turbidity ceases, and the water becomes pure. 
When sinking in gravel or clay, the bottom of the well frequently becomes filled 
up, and it is necessary to remove the obstruction before a pure supply of water can 
be obtained. 
To do this a pipe of small diameter is lowered down the well (the pump being 
attached to its upper extremity) to within about 1 in. of the solid material (as 
ascertained by the lead). 
Water is then poured down the outer tube, and pumped up the inner one, 
gradually washing away the surface of the material until the well is cleared out to 
the bottom, as ascertained by the length of the inner tube, which can then be 
removed and the pump screwed on to the well. 
