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but the 760th part; or the whole, would export some 76,000,000 tons per year to San Francisco alone. To transport this tonnage, 15,200 1,000-ton steam or sailing vessels would be required, making five round trips per year. Assuming that San Francisco is but a distributing point, and that, too, by rail, it would require 13,800 freight trains, carrying net 300 tons per train, or 690 trains per day, or a train would have to leave our city about every two minutes, day and night. Allowing that the trains would require twenty days to make the round trip, the above number, 13,800, would be required.

If we take but twenty per cent, of the above, we would yet have a practical trade so vast that a city of a million or more inhabitants would naturally be required to take care of it.

Assuming again that the value of the exports of San Francisco to the Hawaiian group would compare as favorably with all other portions of the island world of the Pacific, the value would be something like #2,432,000,000 per annum, over three times the value of the annual exports of the United States.

PANAMA CANAL.

The proposition to connect the Atlantic and Pacific Oceans by means of a canal, the work on which is now under, it is to be hoped, successful progress at Panama, will add greatly to the world's interest in the Pacific Islands. Of the many projects to connect the two oceans, if we add Captain Ead's ship railway, and similar schemes, the canal at Panama is about the fifty-fourth. The subjoined memorandum statement of the three most prominent undertakings, and for which I am indebted to the valuable writings of Captain W. L. Merry, gives a comparative idea, not only of their magnitude, but of the practical results, that will be derived after the completion of either of the proposed routes.

MEMORANDUM OF PANAMA -CANAL.

Length of Panama railroad, 47.5 miles; length of United States Panama lock canal, 41.7 miles; engineer's estimate of cost of United States lock canal, including 20 per cent, contingency, $94,511,360; engineer's estimate of French sea level canal, including 10 per cent, contingency, $168,000,000.

Mercantile estimate of probable cost of French low tide level canal, San Francisco Board of Trade, $300,000,000.

Summit level of Panama canal survey, 295.7 feet; engineer's estimate of time for construction, 8 years.

To judge of the character of this work, the following estimate from the French survey is given herewith:

Length of dam, 5,000 feet; height above bed of the Chagres, 130 feet; height above canal level, 172 feet; height above canal bottom, 199 feet; estimated cost, 10 per cent, contingency, $20,000,000.

It will be noted that the bottom of the canal passes in front of the dam, seventy feet below the river bed, and that the Chagres River is wiped out of existence between the canal and the Atlantic. When the enormous rainfall, the violent freshets, and the large amount of sediment and floatage, brought down by floods, are considered, one begins to realize the enormous difficulties of the project, the doubtful results of the attempt, and the impossibility of estimating additional cost, which may be caused by contingencies liable to occur. Presuming its completion, will this dam not be a standing menace to the canal, passing in modest silence two hundred feet below its top? What will be the result of a moderate earthquake shock, or of seepage during the rainy season? Thus obliterating the Chagres, the canal passes on into the Culebra division, cutting through an elevation a few inches less than three hundred feet—of course, with an immensely increased excavation, as compared with the United States survey, but encountering otherwise no formidable engineering obstacles—and finally reaching the Pacific through the valley of the little Rio Grande, about six miles west of the city of Panama, and there meeting deep water about four miles outside the highwater mark. The mean sea-level of both oceans is now known to be the same; but, while at Aspinwall the tide ebbs and flows from one and a half to two feet, at Panama the tidal movement is eighteen to twentysix feet.

The American, as well as the French survey, overcome the difficulty by placing a tidal lock at the Pacific end of the canal, which completely controls the question. Such is the French survey for a sea-level Panama canal.

NICARAGUA CANAL

Of the route of the Nicaragua canal, the following memorandum will serve for a brief explanation:

Total length of interoceanic navigation, 173.57 miles; canal from San Juan del Norte to San Carlos dam, 35.90 miles; slack water navigation from San Carlos dam to lake junction, 63.90 miles; lake navigation from lake junction to lake end of Pacific division of canal, 56.50 miles: extreme summit level between Pacific and Atlantic Oceans, 150 feet; total length of canal to be constructed, 53.15 miles; engineer's estimate of cost, $52,577,718; engineer's estimate of time for construction, five years.

Mercantile estimate of possible cost by San Francisco Board of Trade, $100,000,000.

Surface of Lake Nicaragua is 107 feet 10 inches above sea level. The Lake is 110 miles long and about 35 miles wide, with average depth of water of 9 to 15 fathoms.

The Pacific division of the canal is 17^ miles long, from Lajas on the lake to the Pacific seaport of Brito.

THE EADS TEHUANTEPEC SHIP RAILWAY.

The survey for this interoceanic project has not been made, and it is accordingly impossible to give an accurate description of the line, or its exact length. The Tehuantepec Isthmus United States canal survey is 144 miles long, to which is to be added about 28 miles of river navigation, making a total of 172 miles; and former surveys for railway and canal service, have found the lowest practicable summit at 754 feet. The canal project for this route was abandoned, because of the high summit, necessitating a large number of locks, with a scant water supply, while a tide-level canal is impossible at any admissible cost. For a ship railway, it offers advantages over any American isthmus, and an ordinary railway is now being constructed there by an American company. The Coatzacoalcos River is a stream of respectable magnitude, running northerly across the northern slope of the isthmus, with twelve to thirteen feet of water on its bar, which it is proposed to deepen sufficiently to admit the largest ships, which can ascend the river about twenty-five miles—how far, before arriving at the Atlantic end of the proposed railway, I presume Mr. Eads himself has not decided. There are no formidable obstacles in the way of building an ordinary railroad across the isthmus, beyond the heavy cuts and fills usually found in a country of that character; and the railroad finds its Pacific terminus at Salina Cruz, near Ventosa, at the head of the Gulf of Tehuantepec, where a port must be constructed. Probably Captain Eads can improve the Coatzacoalcos River for heavy navigation, 25 to 28 miles, and his railroad will be about 123 miles long. He estimates the cost at $75,000,000. It has been my purpose to avoid a discussion of the merits of the three routes here described, but it will be impossible to do so in the case of this project, if the reader is to acquire an intelligent idea of it. My high respect for the ability of Captain Eads, my esteem for him, founded on a slight personal acquaintance, and the fact that I can lay claim to no technical knowledge of civil engineering, are good reasons for approaching this subject with deference, and I must regard myself as merely a student of the project.

Captain Eads takes the ship out of water by a submerged inclined track, on which the cradle is run deep enough to allow the ship to be placed upon it, properly lined and blocked, after which a stationary engine hauls cradle and ship out of water to the railroad proper, where four "Mogul" locomotives are placed ahead of it, on a twelve-rail track, which haul ship and cradle to the other end of the track, where,

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