REPORT OF BOARD OF CONSULTING ENGINEERS, PANAMA CANAL.


 Permit me to make a remark about power. I do think it is of the utmost importance that the Gamboa dam, if it should be a part of the plan, should be built at the earliest possible date, and that electric power should be used. It can be used for the drills, for lighting, and for many other purposes. It can also be used for night work. It is possible to use it partly in transportation and partly in connection with some of the dredging machinery, particularly the pumping, and things of that kind. Of course you can not tell what the developments might be. It would not be econom to change the steam shovels or the engines that are already on the ground, but there are so many ways in which it could be used that it would surely pay for the extra cost of putting in the machinery after the dam is constructed. You would not be justified in building the dam to create electric power, but having the dam, I think you would certainly be justified in the installation of electric machinery.
 Mr. HUNTER. In one of the papers that was read this morning, your figures on efficient work of steam shovels are 800 yards per day and twenty-one days per month. You will perhaps remember those figures in your paper. Does that mean that you reckon on two hundred and fifty working days per year, and not more in that climate, with the conditions there, or is the average of twenty-one days per month founded on other considerations? In other words, how many efficient working days do you reckon on the Isthmus?
 Mr. WALLACE. I consider that, month in and month out, year in and year out, we should get a minimum of twenty-one working days per month. My experience there was that we were able to average about twenty-three or twenty-four days a month in the wet season and the dry season together. I would expect to work more than twenty-one days. I would expect to load more yards than 800 per day, but in making up these figures I wanted to be beyond all doubt on the safe side.
 Mr. Gu1'RARD. Will there be found, without much difficulty, sand, gravel, and stone for the construction of the lock at Ancon-Sosa?
 Mr. WALLACE. There is plenty on the Isthmus, but I should not judge there would be an abundance of them in the immediate vicinity-I mean in the actual vicinity of Ancon. It would have to be brought from some distance. Of course it is true that you could manufacture it by crushing the rock right out of Ancon Hill.
 Mr. HUNTER. Have you not already said, Mr. Wallace, that the best sand for concrete purposes comes from Panama Bay?
 Mr. WALLACE. Yes; I say it is not right at that particular point, but you would get it from the same place from which you would get the other. This is true, that the sand would be more convenient there than probably at any other lock.
 Mr. HUNTER. Have you any acquaintance with the quality of the rock in that Ancon-Sosa saddle? Do you know what class of rock it is?
 Mr. WALLACE. We have almost everything in Ancon that is found on the Isthmus. I do not know about the other hill. I never examined that, but in Ancon Hill proper there is some rock of a limestone nature; there is basalt and trap, and there are shales.
 Mr. GUZ-RARD. Do you think there would be any difficulty in obtaining the necessary material to construct a lock at Ancon?
 Mr. WALLACE. I do not think there would be. In other words, I think, so far as that particular locality is concerned, the question of material need not cut any figure as compared with the lock at any other locality, as there is so much of it. I judge that was the intent of the question.
 The CHAIRMAN. There is harder rock in the vicinity of Ancon than there is anywhere else on the Isthmus. I mean in large batches.
 Mr. GUE'RARD. Will there be any difficulty in deepening and maintaining the maritime channel at Panama to 40 feet?
 Mi. WALLACE. I do not see anything in the way. Of course there are places where there will be some rock to excavate, but there should be no more and no less difficulty than in any channel where you encounter that kind of formation. I have not taken any borings to determine how much rock there is in that channel; the Freich records show this.


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