No. 67.
Mr. Scruggs to Mr. Frelinghuysen.

No. 125.]

Sir: Although the work of cutting the Panama Canal was commenced nearly three years ago, and has been extended throughout almost its entire length, yet the most important practical question connected with the enterprise has during all this time been left undecided. I allude, of course, to the question of locks.

At the International Canal Congress held in Paris in May, 1879, it was shown by American and English engineers who had made the matter a subject of special and careful study that the opening of a maritime water-way across the Isthmus of Panama without locks and parallel sluices would be an impossibility. Nevertheless, Messrs. Wyse and de Lesseps, who had never surveyed the route, but who held an exclusive “concession” from the Colombian Government, reiterated their purpose to open a canal from Colon to Panama à niveau, “without locks or hindrances of any kind.” And since the “congress “had been called merely to ratify what these distinguished gentlemen and their associates had already agreed upon, their “plan” was finally adopted, amid much confusion, by a vote of 72 against 61.

It now turns out, however, despite the confident and oft-repeated assertions of M. de Lesseps to the contrary, that at least two locks will be necessary; and that, in addition, there will have to be parallel canals for the reception of the waters of the Chagres and other rivers, which range all the way from 42 to 78 feet above the sea-level, thus augmenting the original cost of the canal by nearly one-third.

These facts are reluctantly set forth in the recent report of Mr. Dingier, the chief engineer of the Panama Canal Company. I regret my inability to send you a copy of this important report. It is destined to have a marked influence upon the fortunes of the shareholders. I, however, transmit herewith a full synopsis of it, which I find in the London Standard of the 9th of October last.

I have, &c.,

[Inclosure in No. 125.—From the London Standard, October 9, 1883.]

the panama canal.

[From our correspondent.]

M. Dingier, the chief engineer of the Panama Canal Company, has just laid a report before the superior works committee which is of great interest to international commerce. Though the work of cutting the canal has been commenced throughout almost its entire length, yet several of the most important questions concerning the creation of the maritime water-way across the Isthmus of Panama had been left undecided. The report I now have before me, and which I have had some trouble to [Page 120] procure, contains the solutions which it is proposed should he given those questions. Most people are under the impression that the entrance to the Panama Canal is to be open to the sea, without any locks or other hindrances. This, indeed, may have been the primitive intention of the originators of the scheme, hut a more thorough study of the question has shown that though it would be possible to construct the canal under those conditions, there are forcible reasons for closing the canal with a lock-chamber at the extremity where it will join the Pacific Ocean. It has been ascertained that the tides in the Atlantic and Pacific differ very materially. At Colon, on the Atlantic, the difference between high and low water mark is not more than 58 centimeters, whereas at Panama, on the Pacific the average variation in the height of the water is 4 meters, and is sometimes no less than 6. Moreover, high water at Colon is about nine hours later than at Panama; therefore, when it is high or low tide at Panama the tide at Colon is half way between high and low. The maximum difference which could exist between the level of the waters of the two oceans would therefore be equal to half the height to which the tide rises at Panama, on the Pacific. If the canal communicated freely with the two oceans, there would be an alternate current from the Atlantic to the Pacific and from the Pacific to the Atlantic, the duration of each current being about six hours. It may be said that there would, moreover, be no slack water, as the level of the water in the two oceans is reached at the moment when the tide runs the strongest, that is to say, at half water at Panama. It would, under these circumstances, be rash to attempt to calculate the rapidity of the currents in the canal which would result from that situation. By comparison with the canals and rivers which empty themselves into the Bay of Biscay, M. Dingier, however, estimated that it would be something like 2 meters or 2½ meters per second. Naturally, at the point where a vessel was passing, the strength of the current would be increased in proportion to the size of the ship and the amount of water it displaced in the comparatively narrow channel. It is therefore clear to M. Dingier that if the canal were to be allowed to communicate freely with the two oceans the rapidity of the current in the canal would necessitate a suspension of navigation during a certain number of hours at each tide. It is clear, from the above, that the transit power of the canal would be considerably increased if it were possible to prevent the formation of the currents in the canal which would result from the action of the tides. To keep the promise made by M. Ferdinand de Lesseps, and to satisfy the requirements of navigation, it is necessary that vessels should be able to pass out of the canal into the Pacific and enter it from the ocean, at all times of the tide, without either difficulty or obstacle and without preoccupation concerning currents produced in the canal by the tide. To realize this, M. Dingier explains that it will suffice to establish lock-chambers at the Panama extremity of the canal. To enable vessels of all dimensions to enter and pass out of the canal at the Pacific end at all times, M. Dingier proposes that it should be made to terminate in three branches, each furnished with a lock-chamber capable of containing a vessel 180 meters long, one branch to be used by vessels entering the canal, the second for ships passing out into the ocean, and the third to be employed when one or other of the entrances may be under repair. The channel, 100 meters wide, leading from the sea to these locks, will have a uniform depth of 9 meters below low-water mark. It is estimated that to get a vessel through these locks will not take more than half an hour, which time will be much more than compensated for by the absence of strong currents in the canal. The construction of these locks at the Pacific end will enable the company to economize in the cost of constructing the canal something like 33,500,000 francs. If the entrance to the canal at Panama were not closed by locks, firstly (as M. Dingier proves in his report), the current would be so strong as to make the suspension of navigation necessary at certain times, and, secondly, the bed of the canal could not be made level from the Atlantic to the Pacific! It would be necessary to make it slope from Colon to Panama, the bed of the canal at Panama being made 2 meters below the level of the bottom of the canal at Colon. This would necessitate the removal of 10,000,000 cubic meters of soil, which would cost about 45,000,000 francs. The lock-chambers, &c., would cost about 11,500,000 francs, but their construction would permit of the same level being preserved from Colon to Panama, and thus spare the difference between 45,000,000 francs and 11,500,000 francs. M. Dingier points out that the economy of the 33,500,000 franca might thus be made, but leaves it to the superior works committee to decide the matter. If it should not determine to spare that outlay, he asserts that the locks at the Panama end should, nevertheless, be constructed, and the entrance to the canal at Panama closed whenever the currents were found too strong. M. Dingler’s report then proceeds to explain how it is proposed to establish the port of Panama. It will be created on the canal, higher up than the locks. Calculating that it may be necessary to accommodate fifty vessels and a large number of local boats, it is proposed that for a distance of 5½ kilometers the minimum width of the canal shall be 160 meters. Vessels will thus be able to take up their positions on each side of the canal, and still leave a clear passage in the middle of at least 100 meters. At Colon the harbor will be created by the construction of a breakwater, which will protect the vessels from the heavy seas which so often prevail [Page 121] in the Bay of Limon. To render the Panama canal a success there is a difficulty to be surmounted which did not present itself in the cutting of the Suez Canal. It is that of the presence of a large volume, of water on the Isthmus. The rivers which would join the canal are, on the right bank, the Chagres, the Frijoles, the Agua Sarne, and the Gatuncillo; and on the left bank, the Obispo, the Baila Monos, the Jigaute, the Caño Quebrada, and the Emnidad. M. Dingier points out that it would be quite impossible to entertain the idea of permitting the immense volume of water which is carried by these streams and rivers, especially in the rainy season, to flow into the maritime canal, for it would cause violent currents, and the deposit which the water from the hills would leave in the canal would very shortly impede the navigation, and possibly necessitate its suspension. Without going into the long engineering particulars, it will suffice to say that it is proposed that this superabundance of river water shall be taken down to the sea by fresh-water canals on each side of the maritime canal. To avert the danger of floods during heavy rains, it is also proposed to create an immense reservoir in the upper valley of the Chagres. In conclusion, I may add that M. Dingier advises the creation of one large siding, about 5 kilometers long, half way between Colon and Panama, where two trains of as many as 25 vessels each could pass each other without either inconvenience or danger.