Mr. WALLACE. I say, in the worst month we had, in June, it dropped down to about between 400 and 500 yards a day per shovel. That was when we had 25 or 30 derailments every day; when the men were so discouraged on account of the engines getting off the track that they did not see why we should continue the work.

With proper equipment and with the right kind of equipment, which you are getting down there now, I do not see why the estimate of 1,0000 yards a day per shovel is not a very low estimate.

The CHAIRMAN. Is that for ten hours a day?

Mr. WALLACE. For ten hours a day.

Senator TALIAFERRO. You were working eight hours a day, were you not?

Mr. WALLACE. I was working ten hours a day up to about the 1st of May. The last two months I was down there we worked eight hours a day, and then our capacity dropped off very much.

The CHAIRMAN. If you were to work two shifts a day, of course you would gain?

Mr. WALLACE. You would get more than that, of course?
Senator TALIAFERRO. Probably a third more?

Mr. WALLACE. Well, yes; I should say about a third more.

That

is, I have never yet seen work where you could do exactly double the work with two shifts that you can with one; but you can get from 50 to 75 per cent more. When I say a third more, I mean that it would be 50 per cent more. You should do that at the very least. Senator SIMMONS. Do I understand you to express the opinion that a sea-level canal could be constructed within nine years?

Mr. WALLACE. On this tentative plan, nine years is the time it would take from the time the first systematic installation of your shovels would commence. That is based on taking the heaviest halfmile, not the heaviest average 8 miles; because there is one halfmile which has more material in it than there is in any other half-mile, so I have taken the worst half-mile there was.

Senator SIMMONS. Do you mean it would take nine years to dig it, or that in nine years the dam at Gamboa could be finished and the canal be ready for the use of ships?

Mr. WALLACE. What I mean to say is this: That on the sea-level plan there is not any doubt but what the thing which will limit the completion will be that central cut at Culebra. You can build your dams and you can do all your dredging, your harbor work, easily within four or five years.

Senator SIMMONS. Everything else will be ready when that is finished? Mr. WALLACE. Yes.

Senator SIMMONS. And your estimate is nine years?

Mr. WALLACE. I estimated nine years. After that I made an allowance on top of that, and said that I thought ten years would be time enough, and at all events twelve would be an ample estimate for it. Senator SIMMONS. And it would take about three years less time to complete the lock canal?

Mr. WALLACE. Yes; that is, theoretically, I should say there was three years difference between the two plans; but I doubt very much whether that three years would not be eaten up by all sorts of happenings that would arise when you would go to build these immense locks.

Senator SIMMONS. I do not know that I understood you about those locks a little while ago. I understood you to say (and I want to ask if I understood you correctly) that you thought it quite probable that it would take as long to construct those locks as it would to build the canal by the sea-level plan. Do I quote you correctly about that? Mr. WALLACE. Yes.

Senator SIMMONS. By the sea-level plan?

Mr. WALLACE. Yes.

Senator SIMMONS. Then, as the locks would absolutely have to be built, the conclusion would be that it would take as long to construct the lock canal as it would to construct the sea-level canal, would it not? Mr. WALLACE. That is, I would very much doubt but what it would take about as long to build the one as it would the other.

Senator SIMMONS. Then what did you mean when you said that the lock canal could be built probably in three years less time?

Mr. WALLACE. What I said was this: I said that that was based on the time that it would take to remove the excavated material from the Culebra Cut, applying the same process to excavating for the lock canal that you would for the sea-level canal. I said that leaving out of consideration the construction of locks and dams, and only measuring your progress by the excavation of the summit cut, there would be three years' difference in doing that work. In other words, you could excavate the material from the summit about three years quicker on the high-level plan than you could on the sea-level plan.

Senator SIMMONS. Then your conclusion is that we could not get the lock canal ready for use any quicker than we could the sea-level canal? Mr. WALLACE. I doubt very much if you could. That is the impression I was trying to convey.

Senator MORGAN. Mr. Wallace, you said all sorts of happenings might occur in the construction of the locks. To what did you refer?

Mr. WALLACE. Well, for instance, there is something like a million cubic yards of material, I understand, to be used in those locks. If those locks are constructed of concrete (which I presume is what they intend to build them out of) that means practically a million yards of broken rock; it means a million yards of sand; it means a million barrels of cement.

Those three classes of material must be manufactured and transported to the site of that work in properly related quantities. Take cement, for instance. That climate is so moist that even if cement is housed you can only keep it for a limited amount of time on the Isthmus, and it will require a great deal of care to see that that cement is brought there just fast enough for that work and not too fast. It is the same way about crushed stone; you must see that that is properly supplied.

Senator MORGAN. Would you have to bring that across the ocean? Mr. WALLACE. The cement you would bring across the ocean; the crushed stone and sand you get on the Isthmus.

Another point: That million cubic yards of material is practically equivalent to a million tons-that is, in round figures; and on the basis of 500 tons to a train load, it means 2,000 trains. That gives you some general idea of the mass of material that will be required just for those locks alone. That means 2,000 trains of 500 tons per train, net load.

Senator MORGAN. Mr. Wallace, the cut through the Culebra and Emperador heights-that is one ridge, is it not?

Mr. WALLACE. Yes, sir.

Senator MORGAN (continuing). That has been brought down from the upper crest to about what height above sea level?

Mr. WALLACE. It is about 150 feet.

Senator MORGAN. That would be an average through, would it150 feet?

Mr. WALLACE. No; I do not think the average for the whole 6 or 7 miles there would be much over 100 feet; but there are 2 or 3 miles there that will average about 150 feet above sea level.

Senator MORGAN. Yes; that has been cut down in trenches or terraces?

Mr. WALLACE. Yes, sir.

Senator MORGAN. The height of each terrace is about 30 feet?

Mr. WALLACE. No; those terraces are very irregular. They will all have to be worked over again in order to suit steam-shovel work. Those terraces were adapted to the French style of excavator. The terraces which I proposed in my tentative plan were terraces of about 30 feet horizontal and about 25 feet perpendicular until you got down; and then after that you would make the slopes to suit the final section you intended to leave.

Senator MORGAN. Is there any terrace on either side of the excavation as it stands now that passes on the same level or nearly the same level clear through the cut?

Mr. WALLACE. Yes; there were several when was I down there that did?

Senator MORGAN. About how high are they above where the work is now being conducted?

Mr. WALLACE. We were working on those terraces.

Senator MORGAN. So that these terraces upon which you are now operating with your steam shovels go clear through the cut?

Mr. WALLACE. That was the intention. When I left there I was starting to work different terraces through. I commenced one on the east and north of the canal that was about on the rock line, and I was taking that clay back 75 or 100 feet from the edge-the clay that overlaid it.

Senator MORGAN. Leaving out of consideration the repairs which may be found necessary to readjust the levels properly upon the terraces as they have been constructed, and taking the one upon which you are operating now with the steam shovels, you would have to go below that if you worked a steam shovel on every terrace; you would have to go below that to the bottom of the canal; and what would be the distance between the average elevation of this lowest terrace on each side and the bottom of the canal when completed 40 feet deep? Mr. WALLACE. When I left there we were working on several terraces, and where the lowest steam shovel was at work was about 160 feet above sea level; that is, the final depth of the sea-level canal would be about 200 feet below the elevation at which the shovel was working, which was in the highest part of the excavation.

Senator MORGAN. Yes. Now, take the terrace that stands at an elevation of 200 feet above the bottom of the canal, the one you are now working on, or were working on when you left there. You would

want to put in steam shovels upon terraces from that point down to cover the distance of 200 feet to the bottom of the canal, would you not?

Mr. WALLACE. Yes.

Senator MORGAN. So that you would expect the work to progress with some degree of uniformity of breast?

Mr. WALLACE. Yes.

Senator MORGAN. And do all of the work as you went along upon each terrace. Now, you would commence at the bottom of the canal; that would be the first opening you would cut. Of course there would be no terrace there until you got up 25 feet, if you took that for the elevation of your terrace. You would have to excavate 40 feet below sea level, and about how much above, before you got through? No, you would commence with your work about 40 feet below sea level, and then you would have a terrace above that every 25 feet or every 40 feet, whatever the height might be that you would adopt for the terrace; and all of these shovels, as I understand it now, would work practically abreast, each shovel doing its own work on its own terrace. Is that right?

Mr. WALLACE. That is right, only it is a little different from the way you have stated it. The maximum number of shovels that would be at work at any one time abreast would be eight on each half mile. That is, there would be one time when there would be four shovels on each side of the cut in each half-mile of distance, because it takes about half a mile between two shovels in order to put in the necessary track arrangements so that you can get around and work all your shovels independent of each other.

Senator MORGAN. I am trying to get at and to ascertain whether this plan of construction is the one which you have adopted. The digging out of the prism of that canal would be a cut in solid rock? Mr. WALLACE. Yes, sir.

Senator MORGAN. At least 40 feet in depth and 200 feet wide? Mr. WALLACE. Yes; that is what you would get down to finally. Senator MORGAN. I say, finally; I am starting at the beginning of the work.

Mr. WALLACE. I know; but we would not start there. We would start at the top.

Senator MORGAN. You would not start at the bottom?

Mr. WALLACE. No, sir.

Senator MORGAN. Why not?

Mr. WALLACE. If I had a blackboard here I could show you. For instance, say this is the sea here, and this is your hill, like that [indicating].

Senator MORGAN. Yes.

Mr. WALLACE. Now suppose the excavating to start in here-one shovel would go through there [indicating] and then another one would come in here afterwards [indicating], and then after it got in a certain distance another one would follow, and you would work. from both ends toward the center, and you would work down; you would commence up here and you would gradually dig these various terraces out until you would finally reach the bottom.

Senator MORGAN. Could you construct the canal by beginning at the bottom and working up?

Mr. WALLACE. No; because you would have such a steep face in here that you could not get shovels enough to work in it.

Senator MORGAN. You could get how many abreast in the bottom of the canal, 200 feet wide?

Mr. WALLACE. You could probably only get four in there.
Senator MORGAN. Four?

Mr. WALLACE. Yes.

Senator MORGAN. And each one would have a separate track?

Mr. WALLACE. Each one would have its separate tracks; but when you are up here, halfway up in the cut, you can work eight abreast. Now, this diagram (if you will follow the description of these numbers) shows exactly when each shovel starts out, how much of a slice it takes, and how many slices are taken out simultaneously. It is hard to explain it by words; but, for instance, at first there would only be two shovels abreast, and they would dig a section of about 12 feet; and they would put that material on a track that would be on the edges here. Then after that slice was taken out the tracks would be laid in behind those shovels, and these shovels, No. 2, would start in, and take out a bench that would be 25 feet or 30 feet wide, and put that material on cars that would be where the first were.

Then, after the 2's were taken out the 3's would start in and put the stuff over on tracks that would follow the second shovels, and so on with the 4's, and later on the 5's. When you got down to what we call the No. 10 shovels there would be 8 of those. Now, that is not on the immediate bench below, because it is necessary to follow the sequence through to see how they would come. That tenth shovel would be on a bench at least 75 feet wide, and there would be tracks out here where the second shovel had been, and there would be tracks where that ninth shovel was; and the 10 shovels will take out these slices that are shown on this cross section.

It is rather intricate to follow.

Senator MORGAN. What is that heavy cut in the center of your diagram there?

Mr. WALLACE. This.one? [Indicating.]

Senator MORGAN. Yes.

Mr. WALLACE. That is where the shovels are worked in parallel in order to keep a central cut which will be 60 feet wide and average 12 feet below the balance of your excavation. What we call the "pilot shovels" will be at work shoving that depression always forward, ahead of these other shovels.

Senator MORGAN. When you go down to sea level with your shovel work and want to go lower down, 40 feet lower, could you continue your shovel work?

Mr. WALLACE. Just exactly in this same way; yes, sir. The only thing we would do differently, then, would be to leave barriers. You have heard before, in the testimony, reference made to what they call "elevation plus 10."

Senator MORGAN. Yes; I know about that.

Mr. WALLACE. What they mean by that is that you can go down to an elevation of 10 feet above the sea level and have room enough for the water to flow out of your cut by gravity.

Senator MORGAN. I know.

Mr. WALLACE. But when you go below the sea level———