On account of the shifting character of the channels, and the large amount of silt precipitated into the river by the San Carlos stream, it would be almost impossible to utilize the river on this portion as a channel, and even then it is very doubtful whether permanency could be obtained. I have met engineers in the United States

In order to avoid the high ridges and projecting spurs, it must keep close to the banks of, and be but a little elevated above, the San Juan. The canal would therefore be in constant danger of destruction,-—on the south by the river floods, and on the north by the accumulated drainage of an extensive watershed, presenting at all points complicated engineering problems of most difficult solution. By the high-level plan, the largest portion of that watershed is eliminated; and, of the balance yet affecting the canal, a large area is converted into extensive reservoirs, from which the surplus waters can, without difficulty, be discharged over waste weirs on the confining ridges into the low valley on the south, and through the numerous watercourses traversing the same into the San Juan."

Major Dutton says:-"In searching for a route from this critical point to the sea, the earlier surveys disclosed clearly the fact that the southern side of the lower San Juan was impracticable, (1) by reason of the great amount of excavation required; (2) by reason of the many sharp turns, embarrassing to vessels of great size; (3) by reason of the gigantic cost of opening and maintaining a harbour; and 4th and most conclusive of all, the certainty of speedy breaches of the canal by the overwhelming floods of lateral tributaries which the line of the canal must cross. The north side of the river alone offered promises of feasibility. The doubtful feature was the San Francisco river. This stream drains an area on the north side of the San Juan which, in an ordinary country, would not be regarded as large, but which, in view of the excessive rainfall of this locality, was sufficiently large to be very menacing. In dry weather the stream is navigable only by small skiffs; in wet weather it is a powerful stream. It would be extremely dangerous to a location near the river and parallel to it. Such a location, moreover, would involve very formidable excavations and conservative works for a considerable distance below the San Carlos."

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who have maintained the entire feasibility of utilizing the river throughout. But I am of opinion, from what I have seen of similar problems in various parts of the world, but more especially in tropical countries, where all the conditions were similar, that engineering skill, at any reasonable cost, could not control the lower section of the San Juan river through its reaches of sandy flats below the line of the foot-hills. The adoption of the particular line chosen by Mr. Menocal is not only much shorter and less costly, it is necessary for the safety of the canal.

THE WESTERN SECTION.

While the isthmus separating the lake from the Pacific is, at its narrowest point (where is found the very lowest depression in the whole Cordillera), not more than 12 miles in width, the most economical route connecting the lake shore with Brito has a length of 17.04 miles. It starts from the mouth of the Lajas, a small stream draining a limited watershed to the south of the line, and trends south-westerly through a broad valley slightly rising towards the "Divide," which it reaches at a distance of 470 miles from the lake. Descending thence on the Pacific Slope, at the rate of about 9 feet per mile, at a further distance of 13 miles it falls into the narrow, tortuous valley of the Grande, a waterless creek during the dry season, but a stream of considerable flow in the rainy portion of the year. Its maximum volume has been estimated as high as 10,000 cubic feet per second; but this is attained only in times of extra

ordinary precipitation. In this narrow valley, confined by spurs of considerable elevation, projecting from the highlands on both sides, there is not room for the canal and for an independent channel for the stream. A very favourable location has been made for the former, and it will be shown later on what disposition is proposed to be made of the stream. In 1 miles the Grande makes a detour to the westward; and the canal, free from the confining hills on the north, cuts across a broad valley to fall again into the stream at a distance of 9 miles from the lake. At this point the surface of the ground is 30 feet below the assumed level of the lake. The valley continues its uniform descent of about 8 feet to the mile, and gradually expands until, at the junction of the Tola tributary, it attains the maximum width of 12,500 feet. At the fourteenth mile-post, near a place called La Flor, the Grande passes through a narrow gap, flanked by high hills, into the more extensive plain of Brito, bordering on the Pacific. It was the original plan to cut a canal through this valley of Tola, and four locks were contemplated; but another scheme has since been adopted by which the valley in question is flooded and converted into an extensive navigable reservoir. This will be accomplished by closing the gap at La Flor by a dam 1,800 feet long and 70 feet high, so forming a basin, whose surface level will be the same as that of the lake, in fact, forming a part of it. It will be 5'60 miles long on the sailing line, with a depth of water varying from 30 to 70 feet, and a superficial area of 4,000 acres. The advantage gained by this plan consists not so much in saving canal excava