REPORT OF BOARD OF CONSULTING ENGINEERS, PANAMA CANAL.


of the Gamboa dam has been made large enough for the construction of a dam of masonry throughout.
 The dimensions of the Gatun dam are very similar to those recommended by several members of the Board in its discussion, for example, of the 85-foot summit level plan. His estimate of cost, however, appears to be too small. The Lock-Canal Committee of the Board estimated for a dam at Gatun for a lake level of this height, with its spillway and regulating works but without any arrangements to stop seepage under the dlam, a total of $8,000,000. Major Gillette, for his 100-foot summit level, estimates $2,800,000. It is probable that one cause of this discrepancy is the fact that the Board has had the advantage of recent surveys, which show that the maps from which Major Gillette worked were inaccurate.
 The objection to a dam at this site has already been set forth in the discussion on dams.
 The Board is unable to approve the suggested method of preventing seepage under this dam on account of its cost and doubt as to its effectiveness as applied to that site.
 The Lock-Canal Committee of the Board, in its estimate for the 85-foot summit level with flights of three locks each, having less lift but somewhat greater length and width, viz, 1,000 by 100 feet, arrived at the sum of $7,410,000 for each flight. It is very evident to the Board that the estimates of cost given by Major Gillette throughout his paper are very much too small.
 THE 60-FOOT SUMMIT LEVEL PROJECT ADOPTED FOR COMPARISON WITH THE SEA-LEVEL PROJECT.
 This plan provides for a summit level of moderate height and for corresponding dams. Such a canal could be built in somewhat less time than one at sea level. It would have duplicate locks throughout of one lift only between adjacent levels, and could be transformed into a sea-level canal with less difficulty than one with a higher summit level. For these reasons it is preferred by the Board to any other lock-canal project before it.
 The proposed harbor on the Atlantic side is to be the same as described in the sea-level plan. The canal between Mindi and Gatun is to be 500 feet wide, as in the harbor, giving a broad waterway and furnishing material for an earth dam at Gatun of sufficient height to sustain a head of 30 feet. The lift at Gatun will be made with one lock. From Gatun to Bohio the channel is to be 300 feet wide, the banks generally submerged. At Bohio another dam and a lock of the same lift as at Gatun would raise the level to elevation 60. Sluices for the discharge of surplus water are provided in connection with both dams.
 For the control of the floods of the Chagres and the storage of water for canal supply a dam is proposed at Gamboa identical with that for the sea-level canal. From Bohio to San Pablo, about eight and four-fifths miles, the canal is to be 500 feet wide, with channel banks generally submerged; from San Pablo to Obispo, nearly seven miles, it is to be 300 feet wide, and at the latter place reduced to 200 feet, which is to be continued for a distance of seven and one-half miles through the Culebra cut to Pedro Miguel.
 The descent to the Pacific is to be made by two locks, one being at Pedro Miguel, the other six miles beyond, on the west side of Sosa Hill, near the shore of Panama Bay. The canal is to be 300 feet wide between these locks with water surface at elevation 27, the lift at Pedro Miguel being 33 feet, that at Sosa varying with the tide, being about 34 feet at ordinary low water. A spillway to discharge surplus water is proposed at the Ancon-Sosa saddle. The level between Pedro Miguel and Sosa is to be maintained by an earth embankment of considerable dimensions across the Rio Grande opposite Sosa Hill, and smaller ones in the Ancon-Sosa saddle and between the Ancon Hill and high ground to the eastward. These embankments, as well as the Gatun and Bohio dams, are to have unusual width and height above water.
 In Panama Bay a short distance beyond the Sosa lock the line joins the line of the French company, and the width of 300 feet is maintained from the Sosa lock to the seven-fathoum contour. The location of the canal is the same as that of the sea-level canal except a small variation at Gatun and the greater one from Pedro Miguel to the terminus in Panamna Bay resulting from locating the tidal lock on the west side of Sosa instead of in the Ancon-Sosa saddle. In the narrow channel through the Culebra cut the sides of the wet section are to be vertical or nearly so; elsewhere they have slopes suitable for the material passed through. The widths above


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