THE PANAMA CANAL. DOUBTS. THE AMERICAN THEORY AND THE FRENCH.

Progress, Volume II, Issue 8, 1 June 1907, Page 300

THE PANAMA CANAL. DOUBTS. THE AMERICAN THEORY AND THE FRENCH.

The world has accepted the word of the American engineers about the infallability of their plans for constructing a canal over the isthmus of Panama. Therefore the completion of a canal in the time named by the Americans is regarded as a certainty of the near future. On this subject a French engineer of eminence, M. Bunau-Varilla. holds views directly traversing the American standpoint These he has embodied in a lecture which he recently delivered before an audience of distinguished engineers in London. The lecturer labours, so far as the general public is concerned, under the disadvantage of association with the French project which failed so utterly a short few years ago. In spite of this, however, he seems to have made a strong impression on the audience of engineers assembled at the rooms of the Art Society, where the lecture was delivered ; so strong, that the Chairman, Sir J. Wolfe Barry, was generally regarded as having uttered their sentiments when he pronounced that "the scheme appeared to be alike sound and practical, and the result aimed at the best." M. Bunau-Varilla's view is that the Americans are on the wrong track altogether. Firstly, they rely on the dry process of excavation, which, even with the aid of the marvellous steam diggers of the day, is too slow and too expensive — instead of the wet process, or dredging, which is rapid enough and cheap enough even for so large a work as the Panama canal. Secondly, their plans do not. as they ought, in view of the economy of the subject, contemplate an ultimate sea- level canal, which is perfectly feasible. This plan condemns for all time the trade of the Panama canal to the higher charges of a high-level lock system. Thirdly, that the key to the system is a dam of enormous proportions, for the construction of which the necessary materials are not to be found in the giound. Besides this fatal flaw, there is the danger of earthquakes, in that region plentiful, which may at any time sweep away the dam and destroy the whole system. In other words the dam is not likely to be sound under the ordinary circumstances, and may be destroyed suddenly 'no matter whether sound or otherwise. For which reason the French engineer predicts for the Panama project of the American engineers unqualified failure. If he is right there will never be a Panama canal at all under the American

system. In support of his contention that the dry process is too slow, M. Bunau-Varilla cites the fact that the rate of progress since the work was put in hand has been startlingly less than the estimate of the engineers. His own plan is the plan which, after the experience gained by the De Lesseps regime, was offered to the French company, as the only solution of this most difficult engineering problem It provides for a high-level canal in the beginning, which can be used by the shipping of the world in a few years, say five, while the work of dredging proceed s, until in time the sea-level is reached. Afterwards the

traffic will proceed at sea-le^'el for all time. The low-level canal of ultimate construction is described as the '"Straits of Panama " : the daring idea being to construct a strait of diminutive proportions certainly as straits go, but safe tor all time, and of leasonable first cost as well as of economical working. The canal company failed, not for engineering reasons, but because the finance was blundered in the most shocking way. Now that the finance is on a sound basis, the engineer submits his plan once more as the only plan feasible, as the only plan justified by the experience gained by the French company

which, after all, is admitted by all the authorities to have done valuable and useful work. For instance, they cut down the summit ridge from 330 feet to 157, and they took out altogether from first to last 72,000,000 cubic yards of stuff as shown by the report of the Isthmian Commission. The key note of this French project is the use of the wet, or dredging system. The only objection to that system is the excavation of rock under water and its cost. That, M. Bunau-Varilla argued, is done now ac a cost ten times smaller than the one admitted by the International Consulting Board, and this statement was confirmed by the Chairman and other expert speakers during the discussion that followed the delivery of the lecture. Coming down to details, M. Bunau-Varilla showed that by damming the river Chagres at Gamboa to the altitude of 220 feet above the sea, there would be created in the high valley of the Chagres, above the point v.here it came into the canal line, a great lake more than 120,000.000 square yards in area, and 150 ft. deep near the dam. The volume of water would be over two and a half billion cubic yards. This lake would forna a magnificent dump for the spoils of the "Straits of Panama." brought into the lake by barges passing through a flight of locks connecting it to the dredging summit. The Gamboa L,ake gave, by the overflow of its waters, a hydraulic power of 32.000 h.p., which would be sufficient to feed in mechanical energy all the dredges, transport barges, and rock-breaking apparatus of the central cut, where 260,000.000 cubic yards were to be excavated within 7 miles, out of the 600.000,000 cubic yards which formed the total of the excavation of the '-Straits of Panama." 47 miles long. Thanks to the marvellous condition created by nature, thanks to the works carried out by the French, who have lowered the Culebra saddle from 330 ft. above the sea-level down to I^7 ft., a continuous water-level at elevation 170 could be immediately created across the continental divide, where dredges could be installed with the correlative waterborne rock-breaking and transporting apparatus. The dredging works thus organized would allow of a daily excavation of 100,000 cubic yards in the central cut with an insignificant number of 3,500 men. The whole of the excavation of the " Straits of Panama " could be done in 10|- years after the preparatory works, which would need 4£ years. It would cost £30,000,000 sterling, when the sealevel canal, three times less w ide. one-fourth less deep and encumbered by tidal gates, has been estimated at £60 000,000, and the time of completion at 22 years, if made by excavation in the dry. This is the scheme declared by Sir. J. Wolfe Barry to be " sound and practical." Having explained the details of his own plan, M. Bunau-Varilla proceeded to sound a note of alarm at the error of the American plan, which he declared proposes to antagonise the natural forces instead of utilising them : aud to advocate a return to the sound principles of experience- Science he concluded, will of course agree, but as to National Vanity — of which of course there is none in France — what that may do there is no saying.

It is a' challenge thrown down to the American engineers to justify their position. No doubt the Americans will reply in good time. For the present it is only possible to consult the report of an American who has lately visited the works and touched upon some of the points made by M. Bunau-Varilla, by a fortunate anticipation. Just about the time that the lecture was being got ready for delivery, Mr. Fullerton Waldo joined a party of eleven members of Congress which had been organized to visit the canal works and judge for themselves of the prospects. Mr. Waldo had an intimate knowledge of all the canal problems. His conclusions appear in the Magazine of Engineering, (February) and arc very interesting. He gives a splendid account of the work done, and he details the transformation of a notoriously unhealthy line of country to a degree of sanitation and comfort almost incredible. His accounts of the social life of the Isthmus are most attractive, and he does justice to the extraordinary personality of the officers — Chief Engineer Stevens and the Chief Sanitarian, Colonel Gorgas, of the U.S. Army — to whose credit the whole of the sanitation so successful in those deadly regions is given. But the engineering problem is the subject of Mr. Waldo's briefest and most interesting notes. First he lays stress on the order of the stores department, where everything is obtainable from a quire of foolscap to a pile-driving machine, at a moment's notice. He passes on to detail the paving of the streets of the small towns on the route and to describe their water supplies. Of the rate at which the steam diggers were doing their work he has nothing but praise, qualified by the statement that, when the locomotive power is increased, the rate will be vastly accelerated : adding, that as a matter of fact, locomotives

are being hurried to the Isthmus from the best engine yards of the States. That is a plea against the conclusions of the French engineer as to the slow rate of progress with the dry system of excavation. About the big dam at Gatun he has much to say. First, in the direction that delay was caused at first by the thoroughness with which the ground had been probed for the quality of the earth to be used in construction, with the result that the right quality has been proved to exist in unlimited quantities. Secondly, he shows that the dam is by no means of unprecedented proportions. He says in this connection :—: — Standing on the hill above the station at Gatun one gets a very clear idea of the location of the great dam which, next to the excavation of the Culebra cut, is the crux of the engineering problem. The little village of Gatun lies at one s feet, at the confluence of the Chagres and the old French canal. It is a cluster of perhaps a hundred little shacks, with a wooden cross-surmounted Catholic church conspicuous in the midst. The dam, more than half a mile through at the base, will completely obliterate the village site. It extends from the hill whereon we stand, across the valley, 7,900 feet, with a single angle, to a corresponding point in plain sight on the hi]l that forms the opposite wall of the valley. Its cubic contents will be something like 22.000,000 yards. This great dam, with its crest 135 feet above sea-level, and thus 50 feet above the surface of the 85-foot lock level, is not of an unprecedented type. The San Leandro dam, built by the Contra Costa Water Company to supply water to Oakland, California, is an earth dam 120 feet high ; and the Pilarcitos dam, 95 feet high, has stood for 40 years ; this latter dam was built by the Spring Valley Water Company to

supply San Francisco. The north dike of the Wachusett Reservoir in Massachusetts is two miles long, and is planned to have 65 feet of water against it. With a bottom width of 3,100 feet and a top width of about 360, there need be no fear for the stability of the dam." For the present this is all that can be gleaned from the ordinary sources of public information in answer to the extreme criticisms of the French engineer who has impressed a gathering of engineers with the strength of his views. It is somewhat disquieting to learn that Mr. Stevens, the Chief Engineer who is referred to in Mr. Waldo's report in terms befitting the description of a Napoleon among experts should have resigned since the report appeared. Until an explanation of that resignation — the resignation of the man who has carried out the American plans to their present position — is forthcoming, the resignation will be something like a corroboration, for many people, of the warnings of the French engineer who has thrown down a challenge to the Americans. The world must wait with patience for the reply of the American engineers, who are on their mettle and may be expected to defend their position with spirit. The general public, moreover, will find it hard to understand how a dam can be the damning feature of the American plan because of the liabilities to earthquakes, and at the same time the saving clause in the French proposition. On these matters the reply of the Americans to the Frenchman who has impressed certain engineers to a certain extent, will throw probably considerable light. President Roosevelt is one of the foremost writers of America, and one of the most level-headed men in the United States. He has taken up the Panama Canal project, and we may expect his intervention in the controversy, probably in a full-blown message to Congress.