will, by arresting its current, stop the discharge of silt, and, by backing up its water, extend navigation for many miles into the territory of Costa Rica. Ample provision will, of course, be made in the vicinity of the Ochoa Dam for the discharge by weirs and guard gates of the overflow of the two rivers.

The river division of the canal will have a surface width of from 500 to 1,500 feet. Some of the bends of the river will be improved by cutting away projecting promontories, and blasting and dredging to an avarage depth of 41⁄2 feet will be necessary in some places over a distance of twenty-four miles, between the Toro Rapids and the lake. Dredging in soft mud to an average depth of ten feet, for fourteen miles in the lake from the head of the San Juan River, will also be necessary to secure a thirtyfoot channel into deep water. Of the 561 miles of lake navigation, more then forty-two are through deep water. Dredging will be necessary, however, for 1,400 feet from the west shore. Here also, two jetties, one of 1,800, the other of 2,400 feet, will be constructed to protect the entrance of the canal from the swell,

which is produced on this side of the lake by the trade wind.

The western division extends from the lake to the Pacific and covers 17.04 miles. The greatest elevation crossed here is forty-two feet above the level of the lake. The canal leaves the lake at the mouth of a little stream called the Lajas, about midway between La Virgen and St. Jorge, and passes through the depres sion pointed out by Colonel Childs in 1854. For the first 1 miles from the lake it will have a surface width of 210 feet, and a bottom width of 120 feet. Through the succeeding five miles of deepest cutting, it will have a bottom width of eighty feet. Between the divide and the Tola basin it will have a bottom width of eighty feet and a surface width of 184 feet. The excavation will be chiefly through rock. The Tola basin will be 51⁄2 miles long, one mile wide, and have a depth of water of from thirty to seventy feet. For 4 miles it will require no work at all.

To create this basin, a dam 1,800 feet long and seventy feet high, will be constructed at a

place called La Flor. The three locks on the

Pacific side will be situated close together near the La Flor Dam. The two upper locks will each have a lift of 42 feet, while the lowest will have a variable lift ef twenty-one to twentynine feet, according to the state of the tide. This last lock is situated 1 miles from the Pacific, and the intervening section of the canal will be 288 feet wide at the surface, and 120 feet wide at the bottom. The location of Brito is marked at the present time merely by a bight in the shore, formed by a rocky promontory which juts into the ocean at the north side of the mouth of a small stream, called the Rio Grande. From the extremity of this promontory a breakwater 900 feet long will be extended to the seven-fathom limit. Another breakwater 830 feet long will be built out from the beach to a point 800 feet distant from the sea end of the first, so as to inclose a considerable area of deep water. A broad, deep basin will also be excavated inland for 3,000 feet from the shore line, to give ample harbor room.

The estimated time for the transit of the canal by steam vessels is twenty-eight hours. The chief engineer's final estimate of the cost