low lands in arid districts. It is still one of the Nile irrigating
wheels.

[Illustration: Fig. 25]

The building of these wheels is within the scope of the carpenter and
the tinsmith. A short wooden shaft made square or octagonal, as
convenient, with gudgeons in the ends and arms of wood bolted across
each of the sides of the shaft, or as shown in the cut, will form a
frame work upon which a rim may be fastened, to which the blades and
tubular buckets can be attached.

The directions in regard to the current wheel, Fig. 23, may be followed
as to number and form of blades, which must be made in length and width
proportional to the velocity of the stream and the quantity of water to
be lifted by each tubular arm. The tubes may be made of galvanized sheet
iron and attached to the outside of the wheel, as shown in Fig. 25.


THE NORIA OR BUCKET WHEEL.

This is a simple current wheel with pot buckets, rigid or swinging,
arranged on the rim of the wheel, to carry up and discharge the water
nearly at the top of the wheel, and through the long ages that it has
been in use for irrigation, village water supply, and even for private
establishments, has assumed a variety of forms in detail of construction
ranging from the bamboo wheels of the Chinese to the light iron wheels
of modern construction.

We illustrate the most simple of these forms in Figs. 26 and 27, in