[Illustration: PORTABLE PROSPECTING DRILL.]
The Aqueous Works and Diamond Rock-boring Company, Limited, of London,
show at the Inventions Exhibition, London, a light portable rock-boring
machine for prospecting for minerals, water, etc. It is capable of
sinking holes from 2 in. to 5 in. in diameter, and to a depth of 400 ft.
The screwed boring spindle, which is in front of the machine, is actuated
by miter gearing driven by a six horse power engine; the speed of driving
is 400 revolutions a minute. The pump shown on the left-hand side of the
engraving is used to deliver a constant stream of water through the
boring bar, the connection being made by a flexible hose. Suitable
winding gear for raising or lowering the lining tubes, boring rods, etc.,
is also mounted on the same frame. The drill is automatic in its action,
and the speed can be regulated by friction gearing. The front part of the
carriage is arranged so that it can be swung clear of the drill to raise
and lower the bore rods, etc.
* * * * *