next attempt was more successful. This time we anchored the wheel so
that it just cleared the towers, then fastening a couple of long guy
ropes to it, we raised the wheel on edge, while a boy stood on each side
holding the ropes to keep the wheel steady. The anchor rope was now
slowly paid out and the wheel was rolled in between the towers. This
done, the wheel was lifted up and the axle rod was pushed in, with the
ends of the rod resting in slots of the boards on the tall tower and in
the crotch on the shorter one. To prevent the axle rod from working
endwise out of its bearings, we nailed pieces of wood across the crotch
and the slots against the ends of the rod. Then we cast off the anchor
rope and our wheel started work, the cans dipping up the water as they
were carried around by the wheel and pouring it out of the top into the
receiving trough, from which the water flowed down into the filter
barrel.

COOLING THE FILTER BARREL.

[Illustration: Fig. 260. The Water Wheel in Action.]

The trough line was very leaky and a great deal of water splashed out of
the buckets. But for all that, within a few moments our barrel was full
and overflowing. We hadn't figured on its filling so rapidly, but we
soon found a way of utilizing the surplus water. It was led to a
half-barrel in which we washed our dishes, and from there it flowed
through a ditch back to the river. The water for the wash barrel was
taken from the top of the upper filter barrel. But we let the lower
filter barrel flow over so that it would be kept wet on the outside. Our
filter was fortunately placed at a point where a good breeze struck it,
and we shoveled away the earth that had been piled around it so that the
wind playing on the wet barrel evaporated the moisture, making the water
inside very cool.

THE CANVAS BUCKET.

[Illustration: Fig. 261. Bottom of Bucket.]

This same trick was used for cooling our drinking water whenever we went
off on an expedition away from camp. We had a heavy canvas bucket, the
kind used on ships. We would fill this bucket with water and then hang
it up in the wind. The water seeping out of the pores of the bucket
would be evaporated by the wind, and this would, in a few moments, make
the water inside delightfully cool. Such buckets may be bought for $1.50
to $2.00 apiece, but ours was a home-made affair, and made somewhat
differently from the store kind. The canvas used was the heaviest we
could find. A piece 9 in