te,
1.33 h.-p.
For each 750lb. stamp, dropping 6 in. 95 times per minute,
1.18 h.-p.
For each 650lb. stamp, dropping 6 in. 95 times per minute,
1.00 h.-p.
For an 8-inch by 10-inch Blake pattern rock-breaker
9.00 h.-p.
For a Frue or Triumph vanner, with 220 revolutions per min.
0.50 h.-p.
For a 4-feet clean-up pan, making 30 revolutions per min.
1.50 h.-p.
For an amalgamating barrel, making 30 revolutions per min.
2.50 h.-p.
For a mechanical batea, making 30 revolutions per min.
1.00 h.-p."

The writer has had small practical experience of the working of that
excellent hydraulic motor, the Pelton wheel, but if by horse-power in
the table given is meant nominal horse-power, it appears to be high.
Working with 800 cwt. stamps, 80 blows a minute, one horse-power nominal
will be found sufficient with any good modern engine, which has no
further burden than raising the stamps and pumping the feed water. It is
always well, however, particularly when providing engine power, to err
on the right side, and make provision for more than is absolutely needed
for actual battery requirements. This rule applies with equal potency to
pumping engines.

TO AVOID LOSS IN CLEANING UP

The following is a hint to quartz mill managers with respect to that
common source of loss of gold involved in the almost inevitable loss
of mercury in cleaning up operations. I have known hundreds of pounds'
worth of gold to be recovered from an old quartz mill site by the simple
process of washing up the ground under the floor.

If you cannot afford to floor the whole of the battery with smooth
concrete, at all events smoothly concrete the floor of the cleaning-up
room, and let the floor slope towards the centre: where a sink is
provided. Any lost mercury must thus find its way to the centre, where
it will collect and can be panned off from time to time. Of course an
underground drain and mercury trap must be provided.

IRON EXTRACTOR

When using self-feeders, fragments of steel tools are especially liable
to get into the battery boxes or other crushing appliance where they
sometimes cause great mischief. I believe the following plan would be a
practicable remedy for this evil.

By a belt from the cam or counter shaft, cause a powerful electric
magnet to extract all magnetic particles; then, by a simple ratchet
movement, at interva