REPORT OF BOARD OF CONSULTING ENGINEERS, PANAMA CANAL.


 EARTH DAM AT BOHIO TO CONSIST OF A MOUNTAIN OF CLAYISH SAND TRANSPORTED AND DEPOSITED BY WATER.

 The solidity of the structure must rest on the system of construction, not on the good will and vigilance of the laborer, and it must be conceived in such a way that nearly unreasonable margins of safety provide against all imaginable risk. This is the base of the project of the Bohio dam which I have had the honor of submitting to the President of the United States.
 Let us first see the dimensions. If we give 2,500 to 3,000 feet thickness to the embankment at the foot-that is to say, about six or seven times the thickness of the Comit6 Technique's embankment-and 1,200 feet thickness at the crest-that is to say, about twenty-five times the corresponding dimensions of the Comit6 Technique's project-we shall have fulfilled the conditions as to the necessary margin of safety.
 But it is also necessary that, in addition to such margin, the quality of the structure should be as high graded as that of the most perfect corroi the Comit6 Technique could hope to obtain and which it would never have obtained.
 Let us first consider the quality of the natural ground in the valley above Bohio. It consists of an indefinite quantity of sandy clay easy to dredge, easy to put in suspension in water, easy to manipulate with centrifugal pumps. Thanks to these exceptional qualities it will be easy by purely mechanical manipulation to send the material in a state of extreme division in suspension in water to the location of the dam. The water will drop the material thus transported in a state of ideal adherence and cohesion necessary for a perfect dam. The system I propose guarantees entirely for the embankment a quality never obtainable by the hand methods of the corroi construction, Aside from the advantage of giving an exceptional perfection to the huge mass of impervious material which will be thrown across the Chagres Valley this method has also that of simplicity and rapidity.
 In my letter to the President of the United States I explained how two powerful dredges, excavating and working in combination with a corresponding number of centrifugal pumps which elevate, by the Dutch method, the water-bearing material to the necessary height for transporting purposes, would make certain the execution of this huge deposit within one year. This method leaves nothing to desire from a practical standpoint.
 Now, gentlemen, will you allow me to answer an observation which is inserted in the pamphlet bound in gray which was prepared for your studies and which bears the title The Panama Canal, Part IV, projects of M. Bunau-Varilla and of," etc. In the remarks that precede my letter to the President it is said that the estimate of four years' time for the conclusion of the Bohio works is oversanguine." This appreciation is based upon the fact that the Comit6 Technique estimated at ten years the time necessary to execute the works at Bohio.
 This last statement is perfectly true, but I do not think it absolutely just to dispose of my estimate of the required time on account of the estimate of time made by the Comit6 Technique for their own project. It is not just, first, because the estimates of time do not apply to the same method of construction and therefore are not comparable, and on the other hand, because the estimates of time of the Comit6 Technique have always, and justly, been considered as overcautious.
 It is highly probable that the method of constructing the Bohio dam as I propose it would have justified the Comit6 Technique in reducing by three or four years, at least, its estimate of the time necessary, and that therefore they would have admitted six or seven years as sufficient for the execution of the Bohio works.

ESTIMATES OF TIME OF THE COMITE TECHNIQUE CAN BE REDUCED IN THE PROPORTION OF 4 TO
 5.375, ACCORDING TO THE ISTHMIAN CANAL COMMISSION.

 On the other hand, I said at the beginning that the estimate of time of the Comit6 Technique could very conservatively be reduced by one-third. It is interesting to note that this has been also more or less the opinion of the Isthmian Canal Commission, as can be inferred from their


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