ing operation will put things
right. Remove the bearing on the pulley side, and enlarge the hole
slightly. Then bore a hole in the centre of a metal disc, 1 inch in
diameter, to fit the bearing; and drill three holes for screws to hold the
disc against the case. Rub disc and bearing bright all over.

Replace the bearing in its hole, slip the disc over it, and push the shaft
through both bearings. Move the disc about until the shaft turns easily,
mark the screw holes, and insert the screws. Finally, solder the bearing to
the disc while the shaft is still in place.

The wheel is a flat brass disc 4 inches in diameter. Polish this, and
scratch on one side twelve equally spaced radii. At the end of each radius
a small cup, made by bending a piece of strip brass 1/4 inch wide and 1/2
inch long into an arc of a circle, is soldered with its extremities on the
scratch. A little "Tinol" soldering lamp (price 1s. 6d.) comes in very
handy here.

To fix the wheel of the shaft requires the use of a third small piece of
tubing, which should be turned off quite square at both ends. Slip this and
the wheel on the shaft, and make a good, firm, soldered joint. Note.--
Consult Fig. 107 for a general idea of the position of the wheel, which
must be kept just clear of the case by the near bearing.

[Illustration: FIG. 107.--Plan of water turbine, showing arrangement of
nozzle.]

The nozzle should be a straight, tapered tube of some kind--the nose of a
large oil can will serve the purpose. The exit must be small enough to
allow the water to leave it at high velocity; if too large, the efficiency
of the wheel will be diminished. To the rear end of the nozzle should be
soldered a piece of brass tubing, which will make a tight fit with the hose
pipe leading from the water supply. A few small brass rings soldered round
this piece will prevent the hose blowing off if well wired on the outside.

Now comes the boring of the hole for the nozzle. Fig. 106 shows the line it
should take horizontally, so that the water shall strike the uppermost
bucket just below the centre; while Fig. 107 indicates the obliquity needed
to make the stream miss the intervening bucket. A tapered broach should be
used to enlarge the hole gradually till the nozzle projects sufficiently.
If the line is not quite correct, the tip should be bent carefully in the
direction required. One must avoid distorting the orifice, which should be
perfectly circular; clean it out wit