Japan is already traversed by a system of railways, and its population
is entering more and more into the footsteps of western civilization.
This movement, a consequence of the revolution of 1868, is extending
to the public works of every kind, for while the first railway lines
were being continued, there was in the course of excavation (among
other canals) a navigable canal designed to connect Lake Biwa and the
Bay of Osaka, upon which is situated Kioto, the ancient capital of
Japan.
The work, which was begun in 1885, was finished last year, and one of
our readers has been kind enough to send us, along with some
photographs which we herewith reproduce, a description written by Mr.
S. Tanabe, engineer in chief of the work.
The object of the Kioto-Fu Canal is not only to provide a navigable
watercourse, putting the interior of the country in connection with
the sea, but also to furnish waterfalls for supplying the water works
of the city of Kioto with the water necessary for the irrigation of
the rice plantations, and that employed for city distribution. It
starts from the southwest extremity of Lake Biwa, the largest lake in
Japan, and the area of which is 800 square kilometers. This lake,
which is situated at 84 meters above the level of the sea, is 56
kilometers from the Bay of Osaka. As this bay is already in
communication with Kioto by a canal, the Kioto-Fu forms a junction
with the latter after a stretch of 11 kilometers and a difference of
level of 45 meters between its extremities.
[Illustration: FIG. 1.--EXTREMITY OF LAKE BIWA AND BEGINNING OF THE
CANAL.]
The lake terminates in a marshy plain (Fig. 1), in which the first
excavation was made. This is protected by longitudinal dikes which
lead back the water to it in case of freshets. At the end of this
cutting, which is 100 meters in length, begins the canal properly so
called, with a width of 5.7 meters, at the surface, and a depth of 1.5
meters, for a length of 540 meters. It then reaches the first tunnel
for crossing the Nagara-yama chain. This tunnel is 2,500 meters in
length, 4.8 in width and 4.2 in height. The water reaches a depth of
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.]
The second branch traverses a small tunnel, crosses the valley of the
emperors' tombs upon an aqueduct of 14 arches (Fig. 3), and reaches
Kogawa, a faubourg north of Kioto, after a stretch of 8 kilometers.
Its slope is greater than that of the main canal, from which it
derives but 1.4 cubic meter. The 7 cubic meters remaining may be
employed for the production of motive power under a fall of 56 meters.
It is proposed to utilize a portion of it, at the point of bifurcation
and at the top of the inclined plane, in a hydraulic installation that
will drive electric machines. The total cost of the work was one
million dollars, a third of which was furnished by the imperial
treasury, a quarter by the central government, and the rest by various
taxes.--_La Nature._
* * * * *
HOW TO FIND THE CRACK.--Most mechanics know that by drilling a hole at
the inner end of a crack in cast metal its extension can be prevented.
But to find out the exact point where the crack ends, the _Revue
Industrielle_ recommends moistening the cracked surface with
petroleum, then, after wiping it, to immediately rub it with chalk.
The oil that has penetrated into the crack will, by exudation,
indicate the exact course and end of the crack.
* * * * *