XII REPORT OF BOARD OF CONSULTING ENGINEERS, PANAMA CANAL.

borings or exact topography, with the exception of the Gigante spillway. Their cost can not be accurately estimated without further examinations, but under favorable circumstances cen hardly be less than $1,000,000.
 The streams taken into the canal, whose beds at point of junction with the canal are considerably above the canal prismi, are to be discharged over masonry stepped aprons or through metallic discharge pipes, or these beds will be sloped and lowered so as to prevent objectionable currents at junction points." Tfhe elevation above sea level at which these streams reach the canal is given in the foregoing table, and varies from 13 to 165 feet. A provisional treatment of such important features of a sea level-canal should not be considered. From the point of view of thoroughness and permanency, the sloping and lowering of the beds so as to prevent objectionable currents at junction points would not be good practice. It may be surely anticipated that the accelerated velocity down the increased slope, unless its bottom and sides are lined with masonry, will operate with destructive effect both on the lowered channel and the bed and banks of the canal. Metallic discharge pipes are not adapted to this purpose on streams which are torrential in character and may bring with their flood drift trash and bowlders. The use of mason ry- stepped aprons must therefore be considered, under the conditions presented by most of these streams, as the only advisable way of bringing them from a high to a low level. The construction of these would necessarily be very heavy and therefore very expensive. As in the case of the dams, the sites of those aprons have not been carefully examined, and the estimate of cost can only be a rough approximation. It is the opinion of the Commission that the sum of $3, 500,000, assigned by the majority of the Board to the completion of the diversion channels, the construction of the dams and spillways, and the construction of these aprons, is inadequate, and should be increased by at least $6,500,000, which, with the usual 20 per cent added for contingencies, makes an increase of $7,800,000 to this item of the estimate.
 If the foregoing increases be added to the $247,000,000 estimated by the majority of the Board, the cost of the sea-level canal will be found to be $272,000,00.
 The time required to build the canal is estimated at twelve to thirteen years. The number of unknown factors which enter into this estimate is still greater than in the case of estimates of cost. There are two methods available for reaching a conclusion upon the subject. One is that followed by the Board, viz, to assume that the largest single piece of work-the Culebra Cut-will fix the time required, and that all other work can be completed while that is being executed, then to ascertain how many excavating miachines can be employed at one time in the Culebra cut, and then assign to each machine its daily or annual working capacity, under the conditions which prevail there. There is great uncertainty about all of these elements. The number of steam shovels which can work to advantage in Culebra cut is not known, lbut is pr obably much less than the number mentioned in the report, 100; and there is no experience to show what the output of a steam shovel will be under all the extremely varying conditions which obtain there. The other method is to examine the results obtained in the great operations of the old French company in this same work. It is not unusual to hear that company spoken of lightly, but it is to be remembered that it had at its head men who had recently built the Suez Canal, that it had the advice of the best engineering talent in Europe, and that its pecuniary resources for some years were practically unlimited. After devoting the years 1881 and 1882 to preliminary work, it began operations on a large scale in the early part of 1883, and continued them until the latter part of 1888, about six years or seventy-two months. It excavated altogether about 72,000,000 cubic yards of material, or about 1,000,000 per month if we attribute the work of 1881 and 1882 to the -later period, of which about one-third was the easy excavation with dredges in the coastal plains. In doing this it had every inducement that men could have to make haste. Its concession from Colombia for a limited period, its enormous interest charges, and the sanguine assurances of its promoters and managers, all urged the greatest possible speed. The wreckage


along the line of the canal to-day is a demonstration of the feverish energy with which every species of machinery was lavished upon the work. To get the work done was the primary consideration, its cost secondary. The circumstances are now different in several important respects. There have been great improvements in excavating machinery, and means have been found to