but where the boiler power is not
more than required, waste steam from the engine may be employed, but
care must be taken that no greasy matter comes in contact with the
plates. The exhaust steam from the engine may be utilised by carrying it
through tubes fitted in an ordinary 400 gallon tank.

Reducing appliances have often to be placed in districts where the water
supply is insufficient for the battery. When this is so every available
means must be adopted for saving the precious liquid, such as condensing
the exhaust steam from the engine. This may be done by conducting it
through a considerable length of ordinary zinc piping, such as is used
for carrying the water from house roofs. Also tailings pits should be
made, in which the tailings and slimes are allowed to settle, and the
cleared water is pumped back to be again used. These pits should, where
practicable, be cemented. It is usual, also, to have one or two tailings
dams at different levels; the tailings are run into the upper dam, and
are allowed to settle; the slimes overflow from it into the lower dam,
and are there deposited, while the cleared water is pumped back to the
battery. Arrangements are made by which all these reservoirs can be
sluiced out when they are filled with accumulated tailings. It is well
not to leave the sluicing for too long a period, as when the slimes and
tailings are set hard they are difficult to remove.

Where a permanent reducing plant is to be erected, whatever form of
mill may be adopted, it is better for many reasons to use automatic
ore feeders. Of these the best two I have met are the "Tulloch" and
"Challenge" either of which can be adapted to any mill and both do good
work.

By their use the reducing capacity of the mill is increased, and the
feeding being regular the wear and tear is decreased, while by the
regulated feeding of the "pulp" in the battery box or mortar can be
maintained at any degree of consistency which may be found desirable,
and thus the process of amalgamation will be greatly facilitated. The
only objection which can be urged against the automatic feeder is that
the steel points of picks, gads, drills, and other tools may be allowed
to pass into the mortar or mill, and thus cause considerable wear
and tear. This, I think, can be avoided by the adoption of the magnet
device, described in "Rules of Thumb."

There are many mines where 3 to 4 dwt. of gold cover all the cost, the
excess being clear profi