REPORT OF BOARD OF CONSULTING ENGINEERS, PANAMA CANAL XI


remove the terror of yellow fever, both of which conditions favor an increase of output. On the other hand, there must be a much more careful adjustment of the means to the end. Extravagant duplication of machinery, or other reckless expenditure, can not be tolerated. It is hoped and believed that a considerable increase over the French rate of progress can be attained. What the percentage will bec is a matter of judgment, and is not capable of exact computation, but it would seem that the chances of error here are less than where all of the factors are unknown. Here at least the difference between spasmodic and long-contitinued effort, and the reduction of efficiency due to climate and distance from supplies are eliminated. In the opinion of the Commission it would not be unreasonable to hope for ain increase of 25 per cent; which would give an average output of 1,250,000 cubic yards per month. To excavate the 231,000,000 cubic yards of the sea-level canal at this rate would require one hundred and eightyfive months or fifteen and one-half years. There would be at least two and one-half years ait the beginning before this rate could be reached, and at least an equal amount of tim-te at the end, durino'whichi the contracted space at the bottom of the cut would compel a reduction of force. It is to be feared that the time required to construct a sea-level canal would be ighiteen or twenty years, rather than the twelve or thirteen years estimated by the majority, even supposing that the total amount of excavation will not exceed the 231,000,000 Cubic yards estimated. To reach that amount the majority of the Board has adopted steeper slopes in the Culebra cut than any previous board or commission has adjudged applicable. It mnay well happen that these Slopes must be reduced, and the amount of excavation thus increased. The majority of the Board has made no provision for the necessary turning-out places and widening at curvecs. It is not safe to estimate the time required for the construction of a sea-level canal at less than twenty years.
 PLAN WITH LOCKS.

 The plan, recommended by the minority of the Board is a canal with locks, f ollowing in general the same location as the other, but with slight variations therefromi in Limon and Panamna bays. Its controlling feature is a dan to close the valley of the Chagres at Gatun, thus creating an artificial lake of which the surface is to be 85 feet above the sea and which is to constitute thle summit level. The length of this dam will be 7,700 feet, and the height of its crest 135 feet, or 5( feet above the water surface. It will contain about 21,200,000 cubic yards of material, principally the spoil from the excavation of the canal prism. It is provided with ample spillways and regrulating works. A channel 500 feet wide at sea level leads from Uimon Bay to the Gatun dami, where is placed a double flight of three locks by means of which vessels are lifted into the artificial lake. The lake provides unrestricted navigation for a large part of its length, but becomes more contracted as the Continental Divide is approached until in the Culebra Cut the width at bottom is reduced to 200 feet. It finally terminates at Pedro Miguel, where the first lock on the Pacific side is placed, having a lift of 30 feet. By means of this lock vessels are lowered into another artificial lake created by a dam closing the valley of the Rio Grande, and by ttvo other damis closing other depressions, the level of the lake being 55 feet above the sea. The crests of these damns are 80 feet above the sea. Commtunication between the lake and Panama Bay is effected by a double flight of two locks placed near the shore on the high ground called Sosa hill. All locks are in duplicate and have a usable length 900 feet, width 95 feet, and depth over the miter sills 40 feet. The depth of the channel is everywhere at least 45 feet except in the locks and in Limon Bay*N, where it is 40 feet, the depth in Panamna Bay, however, being measured from mean tide and not from dead low water. In the lakes the depth is of termvery m iuch greater, being 75 feet near the Gatun dam, and nearly as much for nmany Tmiles. The width is nowhere less than 200 feet at bottom, and at most places is very much more. The length of the canal from deep water in Limon Bay to deep water in Panama Bay is 49.72 miles. Of 'this 19-i- miles is over 1,000 feet wide, 23 miles is o ver 800 feet wide, 35 miles is over 500 feet wide, and 42J miles is over 300 feet wide. That is, for about half the distance navigation is entirely unrestricted, while for more than two-thirds the distance the channels are 500 feet or more wide, and for only one-seventh the distance, including the locks, are they less than 300 feet wide.


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