DRAINAGE (WESTERN DIVISION).

The proposed route of the canal from the lake nearly to the summit of the Divide cut pursues a right line. The Lajas has its source in the hills to the southward, and in its course to the lake intersects the canal line at a distance of 125 mile from its mouth. At this point the stream will be diverted through an artificial channel, carried along the south side of the canal, and discharged into the lake. A small tributary, called the Guiscoyol, empties into the Lajas near the point of proposed division of the latter, and will drain the country to the south as far as the highest point of the line; the canal follows the general course of this brook. It will be observed that the Rio del Medio, to the north of the canal, drains the country on that side from the vicinity of the Tola basin to the lake, leaving but a small watershed to be drained into the canal, or, if preferred, by a small ditch diverted to the lake. West of the Divide the canal, including the Tola basin, lies within the watershed of the Grande. With the canal wholly in excavation, no doubt could be entertained as to the necessity of diverting that stream; and careful surveys have been made with that object in view. It was found that to make a diversion channel on the south bank of the Grande would be a work involving difficulties and heavy expense. A safer, less expensive, and more satisfactory plan was found to be the diversion. of the stream into the Juan Davila, a tributary of the Lajas, and through the latter into the lake; and a careful

location has been made to that end. (See plan of western division.) The plan requires the construction of a dam near "El Carmen," and the opening of a diversion channel from above the dam, through the valley of Jobite and the watercourse Cumalcagua to the Davila, beyond which no other work will be needed. With the adoption of the basin plan, however, the additional expense demanded by this work seems to be of doubtful expediency. With a large reservoir acting as equalizer of floods, possessing ample facility for discharging the surplus waters, over a weir in connection with the dam, through the lock culverts, capable of discharging 5,000 cubic feet per second, and through the canal itself eastward into the lake, it is believed that injurious results need not be feared by receiving the waters of the Upper Grande into the basin; especially as the extraordinary floods, which seldom occur, are of but brief duration, the usual flow of the stream being insignificant, while for nine months in the year it is nil. The problem admits of a practical and satisfactory solution; and immunity from all danger can be secured, it is claimed, by the expenditure of, say, $1,500,000. From the Tola basin to the harbour the canal traverses a flat valley, with no watercourse to provide for.

TIME OF LOCKAGE.

The traffic passing through the canal will be limited by the time required for a vessel to pass a lock. This question is of importance, in view of possible delays which may occur. It has been urged that the arrival of ships being affected by wind and weather, to a certain extent even in the case of steamers, and greatly in that of sailing vessels, a large number may reach the terminus together, owing to favourable winds, etc. Lesseps made much of this in the days when he still adhered to his sea-level plan at Panama, and he estimated the number of vessels possibly arriving at the same time, at as much as 100 per day. The lockage time he calculated to be at least half an hour, and "there are not a hundred half hours in the day," he said. There seems to be no reason to anticipate any great difficulty in this matter, however, judging from the experiences of the Suez and Sault Ste. Marie canals, for statistics of either do not show that a congestion of traffic is ever likely to be apprehended. In the Sault Ste. Marie Canal vessels of over 3,000 tons capacity are put through the lock under twenty minutes; the whole operation of opening the lower gates, entering the steamer, filling the chamber, opening the upper gates and taking the vessel out from the lock, having been carried out in even nineteen minutes. In the Nicaragua Canal the operation of filling the lock and handling the gates, need consume no