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.

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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.

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FAST AND FUGITIVE DYES.[1]