1.8 meters upon the floor. It was pierced through very varied
materials, such as clay, schists, sandstone and porphyry, and is lined
throughout with brick masonry. The construction was effected by means
of a working shaft 45 meters in depth, sunk in the axis of the work,
at a third of its length from the west side. At the upper extremity
are established sluices that permit of securing to the canal a
constant discharge of 8.5 cubic meters per second. Fig. 2 represents
the head of this work.

[Illustration: FIG. 2.--HEAD OF THE PRINCIPAL TUNNEL.]

Starting from the tunnel, the canal extends in the open air for a
length of 4,500 meters. To reach the basin of Kioto, it traverses the
Hino-oko-yama chain of hills, through two tunnels of the same section
and construction as the one just mentioned, and of the respective
lengths of 125 and 841 meters. Traction in the tunnels is to be
effected by means of an immersed chain.

On leaving tunnel No. 3, at about 8,400 meters from its origin, the
canal divides into two branches. The first of these, which is designed
to serve as a navigable way, has a slope 0.066 per meter for a length
of 540 meters. It is a true inclined plane, which the boats pass over
by means of a cradle carried by trucks and drawn by a cable actuated
by the fall furnished by the other branch. At the foot of the inclined
plane, the canal widens out to 18 meters at the surface, with a depth
of 1.5 meter, and, through a sluice, joins the Osaka Bay Canal, after
a stretch of 2 kilometers.

[Illustration: FIG. 3.--AQUEDUCT OVER THE VALLEY OF THE TOMBS OF THE
EMPERORS.]