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General Davis. Yes, sir.
Senator MORGAN. Is there any difference in the width of that berm in respect to the two plans, the sea-level and the lock plans?
General Davis. No, sir; no, sir.
Senator MORGAN. So that that berm, when it acts as a means of catching whatever may slip from above, is the same in both cases?
General Davis. Exactly; yes, sir.
The majority of the Commission and the minority of the Board think that a sea-level canal will require from fifteen to twenty years and the lock canal nine years. The sea-level task is a plain, simple task of excavation and removal, there being of what may be called - works of art” an item of $6,920,000 for the tide lock and accessories, while in the lock project there is allowed for similar structures, such as locks, sluices, spillways, moval dams, etc., $35,267,000.
Senator MORGAN. Right there I think it is appropriate to ask a question about this sea gate. Some of the engineers who have been before us say that by digging the sea-level canal in from the 40-foot contour in the Bay of Panama, with a width of 300 feet (I think that is the way they projected it), the sea gate could be dispensed with.
General Davis. Men have expressed that opinion; yes, sir.
General Davis. I should hardly be willing to adopt it, with the information that I have and, I think, with the information that exists, because the data to enable one to pass upon that subject is not satisfactory. The currents in a waterway are governed by so many conditions that it is difficult to predict what those currents will amount to in velocity unless you have perfectly well-known conditions. There is an engineer in New York, who is chief engineer of the city of Brooklyn, who has written to every member of the Board and to a great many other people, stating that in his opinion this tide lock is not necessary at all. It is not at all necessary, he thinks. He cites the opinion of a Frenchman by the name of Boussinesq, of the French Academy, who some eighteen or twenty years ago made a report on that subject for Mr. De Lesseps, and he expressed the opinion that the currents in the Panama Canal at the Panama end would not exceed 3 miles an hour. I think that was the figure.
Senator MORGAN. At high tide?
General Davis. At high tide, or rather at the time of greatest tidal flow.
Senator MORGAN. Yes.
General Davis. Because at high tide it is slack water, and the same at dead low water.
Senator MORGAN. At the time of greatest pressure, in other words?
General Davis. Yes, sir. Now, a member of the Board, wishing to get light on the subject, consulted a college professor who was thought to be a very competent hydraulician, and gave him the facts concerning the Panama Canal—told him how wide it was proposed to make the canal prism, what distance it was across, and how much the tidal oscillations were—and asked him to compute the current that
would be derivable from this range of tide, and where that current would have greatest velocity. This professor made a calculation and submitted it, and demonstrated to his own satisfaction that there would be a current of-I have forgotten now; I think it was 9 miles an hour—and that the greatest velocity of that current would be at Colon, 50 miles from Panama, at the point where the Panama Canal entered the Atlantic Ocean. The whole thing was so absurd that even the gentleman who had invited the opinion rejected it as useless. And so it is a subject beset with a good many difficulties.
In the Manchester Canal there is a somewhat analogous case. The Manchester Canal enters the Mersey just above Birkenhead, just above Liverpool. Liverpool has a maximum tide of 22 or 23 feet, and the tidal oscillation at the point where the Manchester Canal takes out of the Mersey is quite 20 feet—that is, quite as much as it is at Panama for the Panama Canal. Mr. Hunter, who was a member of this Board, and who is in charge of the Manchester Canal, and, indeed, who was in charge during its whole time of construction, said that he was satisfied from his observation of the current at Manchester that a tidal lock would be necessary a part of the time at Panama with a canal of the prism which we proposed.
It goes without saying that if that prism be made wide enough we could encounter that current without any difficulty. That has been pointed out by good engineers. For example, the Harlem River, which joins the Hudson and the East rivers, is a tidal estuary through which our own Government has done a great deal of work in straightening the channel and in constructing a canal for navigation between the Hudson and the East River without going around the Battery. The tide there has 8 or 9 or 10 feet oscillation, and boats pass and repass without any trouble through the Harlem River.
That is about all that I can say to you on the subject, except to call your attention to Suez, which is an object lesson in many ways. The tidal oscillations in the Red Sea amount to about 7 feet or 8 feet, as a maximum. There is occasionally about 8 feet of tidal oscillation twice a day. That tide is felt as far as Tossoum, 12 miles from Suez; there it disappears. It practically is felt up to the opening of what is called the Little Bitter Lake, and there it disappears. Now, that current is variable through this portion of the canal, and at times of extreme tidal oscillation it reaches 3 miles an hour at the point of exit, and varies from that all the way up. But Mr. Quellennec says that that furnishes no obstacle to navigation; that vessels pass repass in both directions, only they observe this rule—that when a ship is going with the current she is never stopped; it is the vessels that are going against the current that are tied up to allow the others to pass. But it furnishes no impediment.
Senator Morgan. Is it therefore possible, in your opinion, by widening the prism of the canal sufficiently, say to 400 feet, out to the Bay of Panama, from Pedro Miguel or Miraflores, to dispense with the tidal gate!
General Davis. I think it is decidedly probable. That is as much as I would dare to say—that it is decidedly probable that it would
Senator MORGAN. Or, if a basin were formed at the foot of the hill there, at Miraflores or in that vicinity, say twice, three, or four times
the width of the canal on its surface, it would probably impede the flow of water from the bay when it is filled up, just as the Bitter Lake does?
General Davis. No, no; the tidal flow will be less the less the area into which the tide piles up—that is, if you have a big lake here connected by a tidal lock with the sea, and that had to be filled and emptied twice every tide—suppose that was the case—the amount of water that would pass through this tidal lock would be enormously greater than it would be if it only had the canal prism to fill up. If the storage for water was limited to the canal prism, it would soon be filled, and then there would be nowhere for the water to go. But if you had a big lake here you would have to fill that lake and empty it twice a day, and all the water would have to pass in or pass out through that tidal lock, and it would take a terriffic current.
The smaller the area of the prism which has to be filled by water and the wider the opening through which it may be filled the smaller will be the current to be encountered in navigation.
Senator MORGAN. The difficulty I am trying to overcome in my mind, General, is just this: That a tidal gate there is subjected not only to the ordinary pressure of the ocean, coming in at 20 or 21 feet of high tide twice a day, but also to the effect of the increase of the inflow of the water from the Bay of Panama by storms that occur there, sometimes of immense rapidity of movement.
General Davis. I was there a year, Senator, and I never saw a wind that amounted to more than a pleasant breeze.
Senator MORGAN. But there have been storms there.
General Davis. I never have heard of one. I have never heard of a gale in Panama Bay.
Senator MORGAN. I can get you the record of it.
Senator MORGAN. They are very terrible when they come, and they occur perhaps three times in a century.
General Davis. Well, I have not happened to observe the record.
Senator MORGAN. I simply had those things in my mind, and I was trying to find out about them.
Senator DRYDEN. General, I was going, before you concluded your testimony, to ask you a question upon this very same point that Senator Morgan has brought out; and I think it is apropos now to say that I have a letter from a very distinguished hydraulic engineer of my State, Mr. Clement Herschel. Do you know Mr. Herschel ?
General Davis. He is the gentleman to whom I referred when I spoke of having had correspondence.
Senator DRYDEN. Mr. Herschel has, in a way, been interested in this project ever since Mr. Burlingame returned from China as minister from China to the United States and Europe. The Chinese were interested in having this canal put through.
Senator MORGAN. Away back in the sixties.
Senator DRYDEN. Yes; about 1866 or 1867, Mr. Herschel writes me. And Mr. Burlingame then consulted Mr. Herschel about this project, and he has kept up his interest in a way ever since. He sent me the
proof of an article which will soon appear, if it is not now in print, in one of the engineering journals. Mr. Herschel believes that this sea-level canal, as designed and recommended in the majority report, can be built without a lock. He states here as a matter of interest that the construction of the Corinth Canal was prevented for two thousand five hundred years after it was first projected, because the engineers did not believe that it was safe to build a sea-level canal without locks. Then he refers in his article to the little canal at Tasmania, and also speaks of the Suez Canal—that it was thought that it must be protected in the same way. That is true, I believe?
General Davis. Oh, yes; those are all facts.
Senator DRYDEN. I would like to quote, in order to have it go into the record, an extract from Mr. Herschel's article, because I think it is interesting and illuminating on this subject. Of course you will understand that this is taken out of the body of his article.
“We have only these data : A slope of water surface on the Suez Canal 27 inches to the mile produced a maximum velocity of 2.67 feet per second (1.6 knots); and it will not require profound hydraulic computations to show that in a Panama canal which will have a maximum slope of water surface of 3 inches per mile on 44 or 45 miles of sea-level canal the engendered velocities will not be inordinately great. Again, the precise computations were long ago made by Boussinesq”—that is the engineer your referred to?
General Davis. Yes; that is the one I mentioned.
Senator DRYDEN (continuing reading): “And other masters of the science of hydraulics, and may be found in the records of the meetings of the French Academy of 1887, volume 104, page 1484, for the cross section of canal then proposed, and will not inordinately vary from those for the cross sections now proposed.”.
“ The situation as found by Boussinesq and his fellow-members of the committee would be exactly similar to the one above described as existing in the Suez Canal—a long water surface, this time 45 miles long-hinged, as it were, at one end and the other end oscillating some 10 feet above and below the fixed mean level of the sea, making alternately a slope of water surface and of currents to the north and to the south about 3 inches to the mile of maximum slope, and maximum currents of about 4 feet per second (two and a half knots). On rare occasions during the year, brought about by strong gales, this may be exceeded, and there is room for the excess without materially obstructing navigation. Vessels do navigate channels having a 5-knot, 6-knot, and higher velocity currents up to 10 and 12 knots in narrow channels on river rapids."
That is an important fact.
“ But it is not the purpose of this article to discuss the debatable questions; and the precise limit of speed at which currents become of material hindrance to navigation is such a question.” etc.
Now, Mr. Herchel states in his article, as I read it here, that there has never been any exact calculation or measurement taken to ascertain the velocity of the inrush of the sea at different periods. That is correct, is it not, General ?
General Davis. That is true. This Board wished very much to make such a study; but the study would have involved a good deal of time, and it was conceived that the Board would have finished its work in three months from the time it was created. It could not take up that subject of discussion, purely scientific study, and solve it or even arrive at any conclusion on it in the time that was available for its purposes. I think it is a subject that the present Isthmian Canal Commission or the chief engineer ought by all means to study with the greatest care; and there should be no pains spared to get every fact bearing on that question of the currents at Panama that is possible. We do know that in the case of the present canal entrance, which sweeps in here [indicating], and at the La Boca wharf, there is an excavated channel reaching clear out here [indicating), and ships have no trouble in coming to that wharf at any time of the tide, and there is a current going in and out there all the while. Even if that wharf had been put away down here somewhere near Miraflores, and the channel were made of the same dimensions, I do not see any reason why ships should not have gone up there to load and discharge if it were desired. There are ever so many facts that tend toward the conclusion that Mr. Herschel has reached.
Senator DRYDEN. If a sea-level canal should be built, whether it can be built with or without locks is certainly a very important question.
General Davis. Yes, sir; a very important one.
Senator DRYDEN. And I think that this contribution from the pen of an eminent hydraulic engineer ought to go into our records and be before us.
General Davis. I am very glad it will.
Senator MORGAN. Allow me to ask this question: If a sea-level canal were dredged out from, say, Pedro Miguel into the bay, could the question as to the necessity for a tidal lock or gate be determined after the dredging of that channel!
General Davis. Oh, yes.
General Davis. Yes, I think so; because before you had the Culebra cut dug out you would have ample time to build the lock.
Senator MORGAN. That is it. So that is a question that for its final determination can be postponed even until after the dredging out of the canal from Pedro Miguel into the bay?
General Davis. Yes, sir; I think it unquestionably can.
Now, I want to say on behalf of the majority—and perhaps I might presume to speak on behalf of the whole Board, but I will not attempt to represent anybody but myself in this matter—that the