A canal by the aid of locks can be constructed between the two seas, upon the line proposed by Col. Hughes, at a much less cost.
Assuming the same dimensions of canal—100 feet wide by 30 feet deep—and the same prices as above, taken from General Michler’s report upon the survey of the canal for joining the Atrato and the Pacific, and we obtain the probable cost of constructing a canal upon this line, as follows:
| For 50 miles of open canal | $ 89,610,150 |
| 12 locks raise the summit level 75 feet | 12,000,000 |
| Breakwater, ship basin, and contingencies | 8,000,000 |
| Total cost of canal | $ 109,610,150 |
This diminution of cost of $32,245,721, due to the absence of a tunnel, upon this route, allows of a margin more than can be required for increasing the number of the locks, or for building, graving docks, and other auxiliary conveniences in the harbors.
The execution of this work would require a cut of less dimensions than the famous Mexican Desague of Huehuetoca, referred to by Humboldt, and described by Admiral Fitzroy as “200 feet deep and 300 feet wide for nearly a thousand yards, and above 100 feet deep through an extent of nearly a thousand yards, (making altogether two miles of distance in which the vast excavation would be capable of concealing the mast-head of a first-rate man-of-war, executed in the last three centuries in Central America,) should induce us to listen respectfully to the plans of modern engineers, however startling they may appear at first.”
Another objection remains to be considered: “Navy Bay is an insecure anchorage, and the harbor upon the Pacific is altogether insufficient for vessels of even moderate draught.” “M. Garella is obliged to include in his estimate the sum of a million and a quarter dollars for the improvement of this harbor.”
On account of the rise of the tide, which varies as much as 22 feet, vessels are compelled to anchor two and one-half miles from Panama, and the passengers and freight are transported in light-draught steamers. These difficulties may be converted, by the use of docks, as in English harbors, into an advantage. The withdrawal of 20 to 23 feet of water at extreme tides affords extraordinary facilities for constructing ship basins and docks upon the natural pavement of rock which covers the bottom of the bay in front of the City of Panama.
On the other side, Limon Bay possesses sufficient depth of water, but is open to “northers.” The entrance of these dangerous winds may be prevented by a stone breakwater, or one composed of screw piles, driven sufficiently near to support iron or flanged plates, sliding vertically into position, one above another, until the requisite height is attained, and braced strongly at the back.
Notwithstanding northers, steamships arrive and depart regularly. The Royal Mail Steamship Company are building wharves of stone and iron, and the railroad company has projected a breakwater for the protection of shipping.
Colonel G. W. Hughes, in a letter to the Hon. J. M. Clayton, at that time Secretary of State, makes the following observations in regard to this route: “The line I have traced for a railroad is, I think, more favorable for a ship canal than that suggested by M. Garella. If we adopt the same depth of cutting he suggests for an open cut, it will leave the bottom of the canal 44 feet above the level of the Pacific at high tide. This would be about ten feet lower than the bed of the river at Gorgona. An open cut two hundred feet deep would obviate all difficulty in crossing the Chagres at Gorgona, while the Rio Grande, the Obispo, and the Mandingo might be converted into an immense reservoir for supplying the summit-level with water, and the Rio Chagres above Cruces, and the Pedro, Miguel, Camero, etc., would furnish the lower level. A spacious tide basin might be constructed at the mouth of the Rio Grande, a few miles west of Panama.”