Popular Science Monthly/Volume 32/December 1887/Inventions at Panama

by Stuart F. Weld

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THE

POPULAR SCIENCE

MONTHLY.

 

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DECEMBER, 1887.

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INVENTIONS AT PANAMA.

By STUART F. WELD.

AS the difficulties connected with the Panama enterprise, from at least certain points of view, increase, its advocates dwell even more than hitherto upon the way in which like difficulties were over-come at Suez. Probably no more pointed or liberal recognition of these has appeared than one contained in a speech of Mr. Gladstone in the House of Commons, July 23, 1883. Speaking for the ministry, he said:

"We think it our duty to do justice, as far as lies in our power, to this great canal company, and to its sagacious and energetic projectors. I say that they have claims upon us—claims to respect and honor; for they have conferred a vast benefit upon mankind, and have conferred it by enormous labors, and in the midst of great dangers, under unparalleled difficulties—difficulties which were, unhappily, in some respects due to the unfortunate action of this country in former times."

It is not to be inferred, however, that if such obstacles were successfully overcome, a similar success is to attend the efforts at Panama. Should some sanguine advocate of the enterprise aver that the stockholders were to be as richly rewarded as those of Suez, and within as short a time, we should listen to the prediction with no every-day skepticism, and should insist upon drawing our own conclusions. Many would as readily accept the wonders of the Arabian Nights as trust to estimates of this description. It will not answer to carry too far a similarity, though its existence is not to be denied, between the completed undertaking and the one De Lesseps has now in hand.

But if, from a financial point of view especially, the prospects of the undertaking are not as bright as its advocates might desire, it is apparent that the company is aware of the difficulties ahead, and in taking what steps under the circumstances are possible. Important announcements were made at the last annual meeting, July 21st. To reduce the ultimate cost, significant changes, De Lesseps stated, had been determined upon. The immense dam, as to which so much controversy has existed, is suppressed. The tide-lock, which was to have been built at the Pacific terminus, is eliminated; also the basin, five kilometres long, at the center of the Isthmus. Nor is the intimation lacking that the dimensions of the channel itself may be reduced. When the president of the company observes that after his inspection of the work, to occur in a few months, he will finally be able to state how the completion of the undertaking is to be effected, one can not but ask whether, to furnish as expeditiously as possible a provisional, serviceable channel, the plan of a lock-canal may not be adopted. Such a solution is not wholly improbable. Subsequently, if the prospects of the enterprise allow, for the above solution the original plan may be substituted; the channel may be cut to the sea-level. The adoption of a lock plan, the summit level to be fed by the Chagres, has been for months, and is still, under consideration by the engineering authorities.

By means of whatever instrumentalities, whether of an engineering or non-engineering type, the company is to proceed with the work, and whatever doubt attaches to the choice of these, none seems admissible as to completion itself. This can hardly be considered a question. Such a view is confirmed by the recent inspection of the work by Lieutenant Charles C. Rogers, U. S. Navy, a brief reference to whose views occurs in an addendum to the present article. While much interest attaches to aspects of the case, which have been referred to—instrumentalities to be employed and the decisions of scientific authorities—there is a question which has not received the attention it deserves, and which is intimately connected with the financial outcome. This it is proposed to examine. How far has the faculty of contrivance and that of invention accelerated the work? How far may it be expected to in future? Such an aspect of the case deserves more attention than many suppose.

The hostility of England to the Suez Canal placed that enterprise for a time in a critical position, by bringing about the abolition of forced labor. But this opposition was in fact the best aid that could have been furnished the undertaking, for it led to the invention of machines which shortened and cheapened the work to a remarkable degree. These inventions have been of service in similar enterprises ever since. Had less efficient devices been brought out at Suez, De Lesseps might well have hesitated before entering upon the more difficult task at Panama. But to meet these more serious obstacles, he possessed mechanical appliances far superior to the rude enginery of 1854. And if, as it is reasonable to anticipate, further radical improvements in machines for this kind of work are made, the financial prospects of the Panama Company will not by any such instrumentality suffer.

Inventions are one of the factors of the case. If the French can prove themselves as expert in surmounting difficulties as they were twenty years ago, the confidence with which they still apply themselves to their task will possess a stouter foundation.

The Hon. John Bigelow, in his report to the New York Chamber of Commerce, after his inspection of the work in February, 1886, expresses the opinion that it is upon this factor (inventions) that De Lesseps relies in his anticipations of early success. He adds that De Lesseps's "own remarkable experience"—referring to Suez—has taught him to look with some confidence in this direction. The question of the ultimate success of the French company might possibly hinge upon such a condition.

The French Academy of Sciences, in a report on the Panama enterprise, dated August, 1880, says, "Every great undertaking, properly conducted, brings about improvements in the processes of execution."^[1]

It may not be entirely safe, even in the case of an enterprise running through ten or twelve progressive years, to count on great and radical improvements in the machinery used. On the other hand, such improvements have helped to solve some of the greatest mechanical problems of the century. Such are the Mont Cenis and St. Gothard Tunnels, and the Suez Canal. Will the Panama scheme receive a corresponding help? It is not to be denied that it has already received assistance of this sort. We proprose to consider the question of inventions, as regards each of the engineering works referred to, with reference especially to what has been done and is to be done at Panama.

We will consider, first of all, the tunnels; next, the canals.

Work upon the Mont Cenis Tunnel was begun in 1857, about two years before De Lesseps commenced operations in Egypt. The working parties in the opposite headings, French and Italian, met on Christmas-day, 1870, about a year after the inauguration of the Suez Canal. The St. Gothard Tunnel was begun after the completion of the Mont Cenis, in 1872; the headings met February 29, 1880. The length of the Mont Cenis Tunnel is over seven and a half miles; that of the St. Gothard about nine and a quarter miles. These are the longest tunnels ever constructed.

The invention, by means of which the progress of the work was facilitated, consists in the use of atmospheric air as a motor. By means of water-power, air is reduced to one sixth its ordinary bulk, and the expansive force thus acquired performs the drilling. Owing to the conditions under which tunneling is done, this method is of signal advantage. Each of the Alpine tunnels was excavated through solid rock, so that blasting was necessary. The use of explosives vitiated the air, while the length of the passage and the impossibility of sinking shafts made the ventilation question a vital one. Had the drills been run by steam, the presence of steam-engines constantly generating smoke and gas would have heated and vitiated the air still further. By the new invention the difficulty was met. The air was compressed outside the tunnel, and conveyed into it by pipes. Here a double purpose was served: by its expansion and liberation the air ran the drills, and ventilated the tunnel The invention which makes this practicable is called the Sommeiller machine, from the name of the chief inventor.

In an address delivered before the American Geographical Society in December, 1879, Major S. F. Shelbourne referred to the manner in which the work in the Alpine tunnels was accelerated by inventions. The subject of the address was the San Blas route for an interoceanic canal. To construct a canal at this point, it would be necessary to cut a ship-tunnel seven miles long; and it was the purpose of Major Shelbourne to show that the advances made in the mechanical arts during the building of the Alpine tunnels, made a ship-tunnel much more practicable than was supposed. It may be added that, at the time referred to (1879), three competent American authorities—Major Shelbourne, Walton W. Evans, and Frederick M. Kelley—advocated the San Blas route. Of all the routes proposed, it was the shortest, the distance being thirty-three miles from sea to sea, against forty-six at Panama. After the work had been begun at Panama, however, Mr. Kelley, whose interest in the subject was so great that he spent out of his private fortune $120,000 for surveys upon the Isthmus, became an advocate of that undertaking.

Major Shelbourne said:

In 1863 the progress made in the Mont Cenis Tunnel with hand-drilling, and powder as an explosive, was an average of a foot and a half a day. After they had commenced to introduce power-drilling and the Sommeiller machine, the progress they made was three times greater—that is, four and a half feet per day.

Major Shelbourne next adduced the testimony of Mr. Shanly, the contractor of the Hoosac Tunnel, after observing that in 1872 the Hoosac Tunnel was "in the rush of its progress" under him. Mr. Shanly stated, in 1874: "The use of the machine-drills saved about two thirds of the expense of drilling. The expense of labor would have been, I think, fully three times the cost of machine-drilling." Major Shelbourne next cited the progress effected at St. Gothard, the contract for which was taken in 1872 by Louis Favre, of Geneva:

In the St. Gothard Tunnel, from 1875 to 1877, with the greater perfection of explosives—for they had come to use nitro-glycerine—and by means of improved drills,^[2] they made a progress of five to one, that is to say, they excavated their tunnel about five times as fast as was the progress in the Mont Cenis Tunnel in 1863 by hand-drilling. Now, in the years 1878 and 1879, by the general improvement of the whole administration in the St. Gothard Tunnel, they are making a progress of more than eight to one, or about thirteen feet per day, through granitic gneiss in a single heading. So that now, if they can excavate and remove rock from a tunnel eight times faster than they could fifteen years ago, you may readily see how much easier, how much more feasible, a tunnel has become to-day on an isthmus-canal route than at the time, in 1870, when the surveys of Selfridge were made. Indeed, these naval officers in their sphere of action were ignorant of and had not conceived as possible these strides of inventive and engineering skill.^[3]

A few weeks after the address of Major Shelbourne, a paper was read before the American Society of Civil Engineers by Walton W. Evans, in which he described the augmented power of the Sommeiller machine during the excavation of St. Gothard. He said:

"I was shown at the St. Gothard Tunnel steam-drills that by slow motion and high pressures would walk into granite as a knife would into cheese; there was nothing used on the Mont Cenis Tunnel to approach them in efficiency. I was shown air-compressors that kept their great reservoirs, night and day, under pressures of 110 pounds to the square inch, and without difficulty; it was with difficulty and uncertainty that the air-compressors of the Mont Cenis Tunnel could keep the pressure up to 60 pounds to the square inch." He adds: "We are clearly a progressive race, and it would be a wise brain that could predict with certainty what advance may be made by some live Yankee in tunneling machinery when we come to cut a ship-tunnel."^[4]

Mr. Evans was, We may remember, like Major Shelbourne, in favor of the San Blas route, and the tunnel which that route involves.

Certain details as to the machinery used in the Alps may be of interest. After hand-drilling was given up, all the drills used were run by compressed air, but the methods employed to compress it varied. At Mont Cenis hydraulic power exclusively was used. Sommeiller employed at first the fall of a column of water in the same way in which it is applied in the case of the water-ram. Afterward he substituted turbine-wheels. To compress the air at the St. Gothard, ordinary steam-power was at first used.^[5] Afterward the improved method of Sommeiller, the turbine-wheel, was substituted. It was found that the amount of water available at the southern terminus was not as large as at the northern; in the former case, accordingly, a higher fall of water was required. A useful or effective fall, as it is called, of 279 feet, was sufficient at the northern end, while at the southern a fall of 531 feet was employed.

The air-compressor used at the St. Gothard had been improved to such an extent by Professor Colladon, of Geneva, that it is often called the Colladon compressor. One of the devices employed was this: The compression of air rapidly generates heat, and to reduce the temperature of the compressing cylinder a circulation of water was kept up all around it. The piston and piston-rod were hollow, and water was introduced into them in like manner. In the shape, finally, of fine spray, water was injected into the cylinder, and thus brought into contact with the air itself.

Not a little interest attaches to circumstances connected with the invention of Sommeiller. This engineer bad two associates, Grandis and Grattoni. All were Italians, and all worked together in the evolution of the problem. No statement has appeared designating the part, or significance of the part, taken by each—a fact somewhat to their credit. Of the three, Sommeiller, however, came to be the best known; a member of the Sardinian Parliament, he appeared in public, as his associates did not. His name suggests a French, or, at least, Savoyard origin, but the inventor was a Piedmontese, and in his writings used the Italian tongue.

The St. Gothard Tunnel is by some considered the most remarkable engineering work extant,^[6] Mr. W. W. Evans, already quoted, writing in 1879—and whatever he says upon this point refers to his fixed idea that the proper route for an interoceanic canal was San Blas—says:

Our weak-kneed people, who get frightened at the idea of a tunnel, should go to Europe, and study tunneling as done there. J found over two hundred tunnels between Nice and Spezzia on the edge of the Mediterranean, cut and used for a very limited railway travel. The line of the St. Gothard Railway is a perfect marvel for tunnels. Nearly one fourth of the whole line is in tunnels. The great or summit tunnel is nine and a half miles long; and in seven places on the line—three on the Swiss side of the St. Gothard, and four on the Italian side—they have tunneled into the sides of the mountain in great entire circles of a thousand metres diameter, merely to get distance and keep the line to their fixed maximum gradient of one in forty, or say one hundred and thirty-two feet to the mile. And what is all this terrible expenditure for? Why, merely to rehabilitate the trade which the Suez Canal has opened, and which the people of the Mediterranean enjoyed, and out of which they built their great cities.

Whether or not we consider the connection as immediate between Suez and St. Gothard, as our author does, it is to be admitted that the introduction of new processes in the case of these tunnels and consequent acceleration of the work naturally encouraged those, like Mr. Evans and Major Shelbourne, intent upon the cutting of a tunnel for ships. Nor would the larger dimensions of such a work necessarily establish its impracticability. The advocates of San Blas counted upon further advances in the tunneling art, just as De Lesseps has counted upon and witnessed like advances in the art of constructing and operating the excavator and the dredge.

We have considered the way in which inventions expedited the cutting of the two greatest engineering works, probably, ever built to promote communication by land; the two greatest to promote communication by water remain to be considered. The Alpine invention, the air-pressure engine, was not used upon the Suez Canal, nor has it been at Panama. The special kinds of work to which it is adapted are tunneling and mining. There could be no question of a tunnel at Suez. On the other hand, in the plan for a sea-level canal at Panama submitted to the Paris Congress, two solutions were presented. The Cordilleras were to be pierced either by a tunnel or open cut. Tunnels of four or five different lengths were proposed, and calculations submitted; but the congress came to no decision on this point. Had the tunnel plan been adopted, the tunnel would have been excavated by the Alpine method, but subsequently the open-cut plan was adopted, and hand or steam drills instead of air-pressure drills have been employed. Nitro-glycerine, however, which had been substituted for powder during. the work at St. Gothard, is largely used.

In considering the two canal enterprises of De Lesseps, we begin with the one completed. As has been said, when, through the intervention of the British and Turkish Governments, the Suez Company had to abandon forced labor, not a little injury was inflicted upon the work. The damage was obviated in part by the indemnity paid by the Egyptian Government, thirty-eight million francs, and in part by the inventions of French engineers. In fact, the company proved to be the vainer. The immense dredges which took such an active part in the rest of the work were contrivances of this period. As to the power and capacity of these machines, we can hardly do better than quote the British historian of the canal, Percy Fitzgerald.^[7] After observing, vol. i, page 202, that the chief contractors, Borel and Lavalley ("men of extraordinary energy and fertility of resource"), came to the task under every disadvantage, and had to establish their workshops and machinery in the desert, he continues:

"They saw at once that the new difficulties as to procuring labor and the limited time allowed by the contract could only be overcome by the aid of machinery of the most daring and novel kind. They accordingly devised those extraordinary dredges which have been the admiration of engineers. . . . No one," he adds, "who has seen an ordinary dredge at its slow work in an English river could have an idea of the bold fashion in which the principle was now applied."

And he thus refers to the general capacity of foreign engineers:

These inventions show the admirable fertility of resource that regulates the work of foreign engineers, who devise machinery to suit the difficulties of each stupendous work; whereas in this country (England) the objection is often, made to such undertakings, that engineering does not furnish means to accomplish them. However this may be, the Mont Cenis Tunnel and Suez Canal are excellent instances in point, the difficulties themselves prompting the discovery of means to overcome them.

For a detailed description of the Suez dredges and their appurtenances, Mr. Fitzgerald's work may be consulted, vol. i, pages 203212. Here we shall only give an account of the principles involved and certain particulars, in which these mechanisms were in advance of preceding ones. The great dredges and excavators employed at Panama go back for their origin to this period. In 1860 an invention was brought out by two engineers, Cavé and Claparède, to facilitate the excavation of canals and cuttings upon railroads. They proposed to use a series of scoops or buckets attached to a revolving, endless chain, and to apply this device both to the ordinary dredge, and to a machine, constructed for the purpose, to be used in dry excavation. This was the origin of the present chain-of-buckets dredge and chain of-buckets excavator.^[8] The latter machine was first used in France in 1860 upon the Ardennes Railroad, between Sedan and Thionville. In an article in "Le Génie Industriel" for December, 1860, containing cuts of the chain-dredge and chain-excavator, it is said: "Such machines may, above all, be applied to the work on the Suez Canal. They will allow of the reduction in a notable manner of hand-labor, and, in consequence, economize a considerable part of the expense."

This statement was written about eighteen months after work on the Suez Canal was begun; just what the writer anticipated occurred. By one of the contractors, Lavalley, the principle of Claparède was successfully applied to dredges; and the Claparède excavator was in like manner improved by another of the contractors, Couvreux, who built what is called the excavateur Couvreux. He took a contract for excavating the seuil d'El Guisr, a ridge which crosses the line of the canal for a space of ten miles, its highest points being sixty-five feet above the sea. This work was finished six months inside the contract time, a result to be ascribed in part to the Couvreux excavator.

One of the improvements introduced by Couvreux consisted in inserting movable bottoms in the buckets. In clayey and adhesive soils the buckets sometimes clogged, so that much time was required to clear them. By the new arrangement the bottom was forced forward, and the clearance thus effected. The bucket having descended, a fresh load of earth drove the bottom into its original place. An article in "La Propagation Industrielle" for September 1, 1868, illustrated by cuts, describes this contrivance, and also another of the improvements of Couvreux. These applied, by-the-way, to the buckets and chains of dredges as well as to those of excavators.

Professor J. E. Nourse, U. S. Navy, in his report on the Suez Canal, published in 1884, says (p. 69) with reference to the French excavator:

In 1865 Couvreux invented a dry dredger which he called the excavateur chargeur. This was a dredger mounted on a car which ran on a tramway parallel with the canal. Its chains and iron buckets descended to scoop up the sand, emptying it into cars, which were themselves drawn up to the summit of the embankment along a succession of tramways.

In the above extract the method is designated by which the earth scooped up by the excavator is got rid of—that is, by means of dirt cars on common tracks. The methods by which the earth brought up by dredges was disposed of were three in number: By the first the sand was emptied into a hopper and thence conveyed through a duct, two hundred and twenty feet long, to and beyond the banks. Steam pumps injected water into the hopper, thus facilitating the discharge. Such a dredge was called a drague à long couloir. At times the banks were too high to admit of this process, and recourse was had to the second method, a mechanism called the Hevateur. It consisted of an elevated railroad, supported by iron posts, partly upon the bank and partly upon a barge between the bank and dredge. Sometimes the dirt-cars carried the earth to a height of fifty-six feet. The cars were attached to an endless chain, and passing upward along the road were emptied, and returned underneath the track. Cuts of these parts of the machinery may be found in Professor Nourse's report already referred to. The third method was the common one of barges or lighters. These were furnished with engines, and carried their contents either to lakes along the line of the canal, or near either terminus, to the sea, and were emptied by means of under- or side-doors.

While, in executing an undertaking like that at Suez, the work consists chiefly in digging, certain parts require to be built up in the proper sense of the term. It was necessary to establish upon the Mediterranean an artificial harbor, and two jetties were constructed. Here was founded the city of Port Said. In the construction of these piers we have an example of the way in which the adversaries of the undertaking asserted, without any sufficient basis, the impracticability of the work. The "Edinburgh Review," referring to the construction of the jetties, said: "Any constructions attempted so as to form an entrance for the canal will be swallowed up. Every block, every stone, will be swallowed up, and we shall not see a single one above water." Mr. Fitzgerald quotes this passage. Referring in particular to the western pier, supposed to be specially difficult of construction, because it was to arrest large bodies of sand moving at this. point of the coast from west to east, he says it had been again and again pronounced impossible to build it, because stone was not to be obtained. There were no quarries, it was alleged, nearer than Lake Timsah or Suez, and quarry-stones could not be dragged one hundred or even fifty miles across the desert. It turned out that there were quarries near Alexandria, whence the stone might have been brought by sea. The contractors, however, as the historian of the canal tells us, "fell back on their own resources"; they manufactured the stone on the spot. The artificial blocks thus compounded were two thirds sand and one third hydraulic lime. Each weighed over twenty tons, and nearly thirty thousand were manufactured and tumbled into the sea. We are assured that "the whole has continued as firm as any structure of the kind in Europe, and is consolidating with every year."

The not carefully considered prediction of the "Edinburgh Review" is almost without significance when compared with others made in the House of Commons by Robert Stephenson and Lord Palmerston. If not the first, Mr. Stephenson was one of the first, of English engineers. In a debate, in June, 1858, Lord Palmerston referred to the scheme as "the greatest bubble that had ever been sought to be imposed on the credulity of the public." The canal, Mr. Stephenson averred, was "physically impossible." It was a mistake to talk of a canal. "It would be simply a ditch. . . . How could a canal be dug eighty miles long, without drinking-water along its course?" But the project, supposed to be so impracticable, did not deserve this sort of treatment. Within thirteen years of inauguration it paid seventeen per cent. That such predictions were falsified, and in so signal, even grotesque a fashion, Mas due, in part at least, to the inventive capacity, the constructive talent, which the undertaking called forth. Upon Lavalley and Couvreux, as well as upon De Lesseps, it devolved to show that ditches might be made serviceable, and a financial "bubble" converted into an astonishing success.

The part of our subject now examined serves, strictly speaking, as an introduction to what in a special sense we have to consider—the work at Panama and connection of inventions with it. Of the three enterprises to which attention has been directed, one—that at Suez—bears a close analogy, both as to the use for which it was built and the character of the machinery employed, to the enterprise at Panama. Such an analogy we do not meet, if we set alongside the case of the tunnels and that of the American enterprise, although from one point of view the work in them resembled more closely that at Panama than that at Suez. In the case of the tunnels, blasting was the regular process, hardly a foot was excavated without it; and a very considerable amount of blasting is required at Panama. Visitors to the works have in fact compared the explosions heard for miles along the excavation to musketry-discharges in battle. In respect to the use of explosives, then, an analogy exists between the Alpine and Panama undertakings. The introduction of nitro-glycerine proved in both cases of great advantage. At Suez, on the other hand, the occurrence of rock was rare, and blasting was resorted to only in exceptional cases.

While from such points of view analogies may be apportioned among the enterprises—two railroad and two ship-canal enterprises—which occupy us, it may not be denied that the work at Panama and machinery used for it bear a special resemblance to those at Suez. Nor may we lose sight of the fact that from an extra-scientific point of view, one individuality, one firm resolve, have, rather than other human agencies, accomplished in each case whatever has been done. As regards the enterprise first carried through, we have considered some of the advances made in the engineering and mechanic arts. To say that these have contributed to the feasibility of the work at Panama is to say but little. They alone, perhaps, have rendered it possible. But for them, the Paris Congress might not have been held; the Panama work might not have been even begun, still less in process of execution.

We come, finally, to the question of inventions in immediate connection with Panama. These seem to consist, thus far, chiefly in an increase in the size and power of the machines, whether dredges or excavators, employed. But ingenuity may at any time supply any need that develops itself, and it has effected part of what has been done already. An opinion formulated by the French Academy of Sciences in 1880, regarding inventions in connection with such work, has been quoted. Lieutenant N. B. Wyse, of the French Navy, whose plan for a sea-level canal was adopted by the Paris Congress, has also touched upon this point. He refers to objections urged against a sea level canal. The plan involved either a huge tunnel or a huge open cut; in either case the work would be much in excess of any of a like character hitherto attempted. He says, "The course of events, experience based upon precise observation, will undoubtedly suggest new processes, or processes scarcely caught sight of at the present day, so as to conquer the difficulties indicated."^[9]

Such anticipations have not been entertained without cause. The major part of the excavation has not yet been done, but already the mechanisms used have been brought to a state of efficiency—one could not say perfection—never reached in the case of any other undertaking. In attempting to trace how this has been brought about, we may begin with one of the first of the new processes introduced, the American method of boring to test the strata and use of the diamond-drill. In

French Excavator (From Lieutenant Kimball's Government Report).

September, 1883, the director-general of the works. Dingier, gave an address in Paris upon the then condition of the enterprise, in which he says:

For the great cutting we have made a large number of American soundings. The Americans in this special matter have made considerable progress, and have rendered us very great service.

Ordinarily, when soundings are made, the yield is brought up in a pulverized state, so that the engineer is obliged to make many conjectures as to the quality of the rock, in order to know what slope to give the excavation.

Generally one is much puzzled. The Americans have discovered a method of bringing up the rock itself in a shape large enough to admit of our judging as to its hardness. A carrot, as the workmen call it, is fetched up. It is obtained by means of a cylinder armed at its lower extremity with black diamonds. This is given a rapid rotary motion; it descends and penetrates into the rock, and in this way we can bring up a block which furnishes the exact consistency of the strata. We placed, before the eyes of the commission,^[10] this morning, a box of specimens taken in Culebra. The result is, that we have a perfect knowledge of the ground, and it is these soundings which enable us to fix our prices.

American Excavator (reduced from cut in "Scientific American").

The following reference to these American soundings occurs in Admiral G. H. Cooper's report to our Government on the progress of the work, dated March 2, 1883. After observing that soundings to ascertain the nature of the soil had been made all along the line, he says:

The first of these soundings were made by French engineers, with the old-fashioned drill and spoon to bring up specimens. This method took many months and was very unsatisfactory; and, finally, the contract for making the remaining soundings was given to Mr. George E. Burt, an American, who is connected with the Panama Railroad Company. Mr. Burt has used the American diamond-drill, and with it has accomplished more work in the past three months than had been done by the other method in the previous two years.

The connection is so close between the consistency of the strata and the slope of the cutting, that the following as to this point will be of interest. The director-general continued:

Well, these borings, made in large numbers at Culebra, showed us that we had to excavate a rock, semi-bard, schistous in quality, having nearly horizontal strata, and that the earth was dry. The result is, that one could not desire better earth for a work of such an exceptional character. We shall be obliged, manifestly, to be very prudent. Accordingly, at the top we have opened the cutting, as if the slope was to be a gentle one. We remove the clayey part which, under the action of water, can be brought to the consistency of paste or mud. Here we have made a very ample opening. But in proportion as we reach clear rock, we make the prism narrower, so as to comprise the cubic contents strictly necessary, with the purpose to make the slope more gradual should experience require it.

The bringing together by an undertaking such as Panama of contractors of divers nationalities, naturally leads to the use of various machines, and it remains to be seen what advantage is to be derived from the sort of rivalry thus established. Here the Panama work may be said to possess an advantage over Suez. The latter was almost exclusively in the hands of French engineers, and was carried through by French contractors and inventors. A single Englishman, Ayton, contracted for a considerable part of the work, but he became bankrupt owing to the withdrawal of forced labor, and the French were obliged to assume his portion.^[11] In the case of Panama, contractors of several nationalties have been employed—French, English, Dutch, Swedes, Swiss, Italians, Americans, and Colombians. The "Canal Bulletin" for February 1.5, 1885, contains a table of contracts, arranged according to nationality, entered into at the time.

After treating of the American use of the diamond-drill, the director-general proceeded to speak of some of the other machines employed.^[12] He said:

The excavation is effected in different ways. We are very eclectic at Panama. We reject no system, no method, and as the earth varies at every step, as the works at one point do not resemble those at another, we can try different ways. At certain places we have mellow earth, which is generally composed, in the valleys, of clay mixed with a feldspathic sand. In such places we can make the attack by mechanical processes. We employ excavators. There are two sorts of excavators, the French and American. The American excavators are very ingenious, and in mellow soil they give satisfactory results. The French excavators are of a type already tested in many places. In clayey and rather adhesive earth they seem preferable. Accordingly, the American papers, knowing, not that We had declared as much, but that facts had demonstrated this superiority, engaged in a little controversy in which patriotism was mixed up. Finally, I wrote to the American contractors that I had never come to any prejudiced decision, that I was wholly disposed to make use of their skill, which I acknowledged to be incontestable, and of their great experience in public works.^[13]

The essential difference between the French and American excavator is as follows: The French, as has been said, carries a series of buckets attached to an endless chain. The American—with which Americans are comparatively familiar—has a single bucket; it is larger than the French buckets, and is worked at the end of a lever. The French buckets, though smaller, revolve rapidly; their number and constant motion compensate perhaps for their size. Cuts of each system are annexed. It may be remarked as to French excavators, that sometimes the buckets ascend filled with earth below the bucket-ladder, as in the cut, and sometimes, the motion of the chain and position of the buckets being reversed, above it. The cut of the French excavator is a reduced cut of an illustration in Lieutenant Kimball's government report. That of the American excavator, also that of the American dredge, found farther on, are reduced from illustrations which appeared in "The Scientific American" in 1884 and 1886. The principle of the French excavator is applied with differences of detail in several ways. There are, or have been recently, at work at Panama the following French or Belgian excavators—named respectively after the manufacturer or designer, Ville-Châtel, Evrard, Weyer et Richemond, Gabert, Boulot, Demange, and Andriessen. There were of the American excavator two types, the Osgood and Otis.

The director-general, after this reference to excavators, observed that in rocky parts excavators could not be used.

In rock excavation a method has recently been tried of breaking up masses of rock by powder and dynamite combined. An explosion of this kind was witnessed by De Lesseps and the party which accompanied him in February, 1886. In a subsequent communication to the French Academy of Sciences,^[14] he gave an account of the wreck of a mass of porphyry amounting to thirty thousand cubic metres, on this occasion. The charge consisted of two parts dynamite to one of powder. Some idea of the force of the explosion may be derived from the pains taken to block the passage which led to the charged chamber. For the space of thirty feet it was packed with masonry. Upon a public occasion soon after, De Lesseps held up a fragment of the rock dislocated, observing that here was one-billionth part of it!

The advantage of using powder and dynamite combined is thus explained. If dynamite alone were used, the breakage would be carried

American Dredge (Reduced from cut in "Scientific American").

too far; the fragments could not be as conveniently loaded by cranes. The effect of powder would be to project the fragments too far, thus damaging, it might be, the neighboring works. As regards the use of dynamite, we might query whether, if a still stronger explosive were employed, the rock might not be reduced to pebbles or sand. In this state it might be handled by the buckets of excavators, and the slower operation of cranes be avoided. We might speculate further, whether the explosives said to have been recently invented in France and Germany, or like substances, might not be of service. If, as is understood, the governments which possess them desire to keep the process of manufacture secret, some difficulty might be experienced in procuring them. But civilization might be the gainer if such inventions were used to blast a thoroughfare at Panama instead of to enhance the rapidity with which human slaughter is carried on.^[15]

Of all writers who have interested themselves in the Panama Canal no one has given the amount of attention to inventions bestowed by Mr. Bigelow in his report to the New York Chamber of Commerce. We can not do better than give his views upon this topic. These, again, may serve to introduce further particulars as to the machinery employed. After observing that the wages of unskilled labor when work was begun were ninety cents a day, and have since advanced to a minimum of $1.75, and that even at this price the company does not readily get the labor needed,^[16] he says:

The question then arises, Must the work be prosecuted under the present conditions?

"When the Jews were required to make brick without straw, Moses came. May not the exigency, like child-bearing, work its own cure?

In all ages and nations, when manual labor has become too costly to do the work for which there was a universal or even a general need, a substitute for it has been promptly devised. It was to the need of economizing muscular labor that we owe the hoe, the wheelbarrow, and the plow. Had laborers' wages never risen above a shilling a day, we should never have heard of McCormick's reaper, or of Howe's and Singer's sewing-machines. It is equally certain that the portion of our planet which lies under the tropics will never play the part in human history to which its territorial extent and productive power entitle it, until our present assortment of mechanical substitutes for muscular power has been very largely increased. Machines do not mind malaria; they are not poisoned by marshy water; they thrive on the black-vomit; they have no fear of chills or sunstrokes; and, what is more, they are never tired, and will work all the days and nights of their natural lives without interruption, if properly fed and cared for.

That is the class of operatives for out of-door work in the tropics, and it is to them that M. de Lesseps must, and I presume does, look for an early completion of his canal; for it is in that direction his own remarkable experience has certainly taught him to look with some confidence. When the work on the Suez Canal was begun, and under climatic conditions much the same as those at the Isthmus of Panama, the Suez Canal Company was entitled by its charter to as many native laborers as it required up to forty thousand, and at an almost nominal price. As these men were drafted into the company's service by corvée, England protested against a "revival of slavery" in Egypt. The Khedive was constrained to break his contract with the company, for which he had afterward to pay an indemnity of thirty-eight million francs, and M. de Lesseps had the mortification of seeing his little army of twenty thousand fellahs dispersed as suddenly and as irrevocably as an April fog.

The logic of the situation promptly suggested the replacing of the men with machines; the putting of slaves without souls or sensibilities in the place of slaves with both. The inventive genius of his countrymen was stimulated by the gravity of the crisis, and in due time from eighty to one hundred dredges, with an appropriate supply of barges, elevators, steam-tugs, locomotives, etc., had taken the place of a large portion of the men withdrawn; and this machinery, with only, four thousand men, increased the monthly output from ten thousand cubic metres to two million, and executed more excavation in the last three years of the work than had been done in the previous seven. May not the scarcity and cost of manual labor on the Isthmus in like manner develop the means of dispensing with at least that portion which the labor market will not cheerfully supply?

The results already accomplished in that direction justify the expectation that, to a considerable extent, it may. There are already at work on the Isthmus machines for dredging and for excavation, far more powerful and efficient than any ever used on the Suez Canal or anywhere else.

It is the opinion of Mr. Bigelow that De Lesseps's "remarkable experience" at Suez has led him to anticipate the forwarding of the Panama work by similar means. This expectation is illustrated by an incident of the Paris Congress. Lavalley, the inventor of the dredges, was there—was in fact a member; and to him De Lesseps referred at one of the sittings as an engineer "who had already invented so many machines, and who, under similar circumstances, would know how to invent more."

Mr. Bigelow observes, with regard more especially to excavators, "There is no reason to suppose that, in the creation of such machines, art and science have reached a limit in any direction." One might say with Arago:

"Croire tout inventé n'est qu'une erreur profonde;
C'est prendre l'horizon pour les bornes du monde."

We can not suppose that an horizon of inventive impossibilities has settled down about Panama.

With regard to Mr. Bigelow's statement that there are at work machines for dredging and excavation "far more powerful" than any ever used elsewhere, it has been already stated that the greater power of these mechanisms is chiefly due to their increased dimensions and the higher steam-power employed. Let us take the "City of New York," the greatest dredge probably ever constructed; built by the American Contracting and Dredging Company, and by them used at Panama. The engines of the largest Suez dredges had a force of seventy-five horse-power. Those of the "City of New York" have a force of three hundred. To run all parts of the complicated machinery, no fewer than eight are employed. The huge ladder which carries the buckets is one hundred and ten feet long; the chain to which the buckets are immediately attached, if ruptured, would reach from the top to the bottom of Bunker Hill Monument. Two discharge-pipes, each three feet in diameter and one hundred and eighty feet long, carry the earth to the banks. By means of steam-pumps, as in the case of the Suez dredges, water is forced into the bell or hopper, and the discharge facilitated. The effectiveness of this mechanism is not due solely to its construction on an enlarged scale; contrivance comes in for part of the credit, and has effected part of the result. One of the peculiarities of the American dredges may be referred to. To steady the vessel and hold the buckets against the bank, two spuds or pile-anchors are employed. In the case of the "City of New York" these spuds are sixty feet high and two feet in diameter. They pass through the hull, one on each side, and the iron chisel point at the termination of each weighs eighteen hundred pounds. This is planted in the bottom. When spud No. 1 descends, it serves as a pivot around which the dredge, carrying the bucket-ladder in operation, slowly revolves, thus traversing the arc of a circle. When No. 1 is raised, No. 2 is lowered, and serves in like manner as a center. After this fashion, planting a foot at a time, this huge digging, spouting creature, as one might term it, advances. The movement through an are is regulated by two distance-lines, so called. These are attached to windlasses, one on each side of the forward deck, the other end being attached to the shore. As one line is drawn in, the other is paid out, and by this simultaneous process the motion in curves is maintained.^[17] A high degree of interest attaches to a structure combining power, ingenuity, and complexity as these are not united in any other mechanism of the sort. Such among contrivances of the kind is the "City of New York."

With regard to the amount of excavation effected by the dredgers of the American Company, Mr. Bigelow sets it down as about double the largest output of any machine at Suez. Lieutenant Kimball, comparing the output of the later American dredges with the best at Suez, sets it down as more than double, twelve hundred cubic metres per hour, as compared with four hundred and eighty.

While in the matter of dredges Americans have contributed of late more than others by fresh devices and an increase of dimensions, the French seem to have effected like results with regard to excavators. Those first employed at Panama had a force of twenty-four horsepower, while the powerful machines more recently sent out have a force of ninety. The French have lately employed in connection with their excavators a mechanism similar to the élévateur, already described. It is called the transporteur, and consists of an elevated structure which performs the same service for an excavator that the élévateur does for a dredge. The earth is deposited from the buckets upon an endless belt. This passes round two drums about two hundred feet apart, and in the interval rests upon friction-rollers. The earth is thus carried outward from the excavation, and at the same time upward.

While, owing to the power and size of her digging mechanisms, the Panama undertaking has quite an advantage over Suez, it is not to be assumed that this advantage may not be further increased. Upon this contingency the decision of important questions may depend. Whether the canal be finished, at least provisionally, as a lock-canal or cut immediately to the sea-level, is possibly one of these. But the decision as to locks will have to be expeditiously arrived at; and if inventors are to step in and affect in any sort of way the result, they have not much time for contrivance and experiment. At all events, we may hope much from the fact that the undertaking is probably in the best hands to which it could have been intrusted. Owing to the completion of former contracts, or the substitution of later for earlier ones, the greater part of the work devolves at present upon French or American contractors. The portion undertaken by the American company consists, it is true, wholly of dredging—the easiest part of the work. There can be no doubt as to the satisfactory, and, should it prove necessary, rapid completion of this part of the undertaking; the chief difficulty lies in the excavation of dry earth and rock, and this is chiefly in the hands of the French.^[18] But American inventions and skill may be as serviceable here as in any other section of the work. It is a pledge of earnest effort that the two republics which have the work in charge have also a greater stake than others in the completion of the undertaking—France, because French capital has furnished the funds; America, because of our need of a shorter water-way between our Atlantic and Pacific coasts. And certainly no other nations offer greater achievements in inventions and execution as a guarantee of success.

Nothing, perhaps, so strongly characterizes this century as the advance man is making in exploring, understanding, and obtaining a mastery over Nature. This process of mastery could scarcely proceed in a more instructive way than by tracing its stages in the instances we have considered. The Alps and the two Isthmuses illustrate it in a not unfitting way. It is safe, probably, to say that the power to excavate earth, to excavate and blast rock, is from five to ten times as great as when a man, wholly unknown to fame, landed with a handful of his countrymen where the city of Port Said nov/ stands and began the excavation of Suez.

In regard to the present enterprise upon the American Isthmus, if we take into account its magnitude and the difficulties involved, it represents without doubt the greatest effort in the line of industry and peaceful achievement man has yet put forth. De Molinari, the Belgian economist, computed that the stock of machinery for the excavation represented the labor of half a million men. Such a fact indicates how far the process of conquering Nature has been carried. The world is watching, with no doubt a degree of skepticism, the way in which the remaining work is being done; and in scientific circles especially an eager interest will continue to be manifested in this great struggle of skill and inventive genius against the forces and obstinacy of Nature. It may be protracted, but it must be in the end successful.

Addenda.—In the article in "The Popular Science Monthly" for July, entitled "The Panama Canal," a statement occurs, page 329, with reference to a report to the Navy Department by Lieutenant C. C. Rogers upon the state of the work in March. This statement is not in all respects correct. The foot-note in which it occurs was based upon a dispatch from Washington, not seen by the writer until after the proof-sheets had been returned. Subsequently a rectified statement was obtained from Lieutenant Rogers. As the views of the latter are soon to be given to the public in full—not a few await them with interest—and probably in advance of the publication of the present article, no special importance attaches to a correct statement here of his positions. The writer quotes, however, with the permission of Lieutenant Rogers, the following from a letter in which he defines his views. The passage quoted refers, not to the chances of the completion of the canal (for its completion Lieutenant Rogers thinks more than probable), but to the chances of its completion by the present company. As regards the dispatch already referred to, he says: "The reporter has called largely upon his imagination in saying that I doubt whether the French company will be able to complete the canal. If the new loan be wisely spent, and a good showing results, their chances for so doing will be good; for the necessity of finishing the work will be apparent." Respecting statements frequently set afloat as to alleged mismanagement, and likewise the company's chances of success, he adds: "One who thinks that the officers do not realize the question in its true aspect, who regards the engineers as inefficient, and the whole company as blind, is in great error. If they do as well in the next eighteen months as during the past year, their chances of completing the canal will be more than good."

1. "Bulletin du Canal Interocéanique," August 15, 1880.
2. An account of the drills used in the St. Gothard Tunnel may be found in Simms's "Tunneling," pp. 305-320.
3. "Journal of the American Geographical Society for 1879," p. 240. In the exhaustive report upon the canal problem submitted to the Navy Department in 1883 by Lieutenant J. T. Sullivan, extracts occur from the address of Major Shelbourne. He is our best authority as to the San Blas route.
4. "Transactions of the American Society of Civil Engineers," 1880, p. 15.
5. Hence, perhaps, the somewhat ambiguous expression used by Mr. Evans, "steam-drills," though it is possible that "steam" is a misprint for "steel." (?)
6. Appletons' "Annual Cyclopædia," 1881, p. 819.
7. "The Great Canal at Suez. Its Political, Engineering, and Financial History," 2 vols. By Percy Fitzgerald, London, 1876.
8. This principle, it is true (the use of the endless chain), was applied to a certain extent in the case of dredging, both in France and England, early in the century. (See Knight's "American Mechanical Dictionary," vol. i, pp. 747, 748.)
9. "Rapports sur les Études de la Commission Internationale d'Exploration de l'Isthme Américain, par Lucien N. B. Wyse," p. 56. Whatever the services of Lieutenant Wyse in the surveys of the Isthmus, between 1876 and 1879, it should be remarked that his work, published last year, "Le Canal de Panama," is not to be read without allowances. The rupture which occurred between himself and De Lesseps in 1880, due to the fact that Wyse, as he himself tells us, expected to be appointed director-general of the work, and was not so appointed, has led to acrid criticisms on his part upon the company. That part of his work which relates to his surveys—the larger part—possesses not a little interest, and is not perhaps open to much criticism; but, as regards his strictures upon the company, the fact referred to is to be kept in mind.
10. The "Commission consultative" of engineers.
11. Fitzgerald's "Suez Canal," vol. i, p. 200.
12. The diamond-drill has recently been put at Panama to a use other than prospecting. The apparatus of the American Diamond-Drill Company is employed to blast rocks under water. Dynamite is the explosive used, and the rock is so thoroughly shattered that a dredge readily removes it. (See "Canal Bulletin," January 15, 1887.)
13. Lieutenant W. W. Kimball, United States Navy, in his report to our Government, after his inspection of the canal in January, 1886, claims that the American excavator excels in stony soil and surface soil with roots, while the French machine is better in light soils and sand. The officer of our navy who inspected the works last March, Lieutenant C. C Rogers, who has been referred to elsewhere, confirms this.
14. "Bulletin du Canal Interocéanique," May 1, 1886.
15. No secret seems to attach to the composition of a new explosive, bellite, to which an article is devoted in the "Scientific American," May 14, 1887. This explosive, it is stated, has been found more effective in quarries than any nitro-glycerine compound.
16. One of the chief difficulties of the company at present is getting an adequate laborsupply. In the "Canal Bulletin," June 16, 1887, the fact is noticed that at several points part of the machinery provided was lying idle, owing to this lack. Several hundred Chinese had arrived but recently, and it was hoped that their labor would prove as effective as that of the Chinese employed upon the Panama Railroad forty years since.
17. For these particulars as to the working of the spuds, etc., the writer is indebted to Lieutenant W. W. Kimball, U. S. Navy.
18. According to the plans of the company, as described recently by Charles de Lesseps, Vice-President of the Suez and Panama Companies, part of the work which it was thought must be done by excavators may be effected by dredging. With this end in view, he tells us, the company is making preparations. It is proposed to introduce into the works, between Gamboa and Paraiso, the waters of the upper Chagres. An analogous plan served the same purpose at Suez: fresh water was introduced from the Nile; nine dredges were carried up by a lock and floated upon it. These operated upon a temporary lake, whose level was seventeen feet above the Mediterranean. Whether such a plan, by some thought impracticable, may be successfully applied at Panama, remains to be seen.
    For a description of the manner in which the Nile water was employed, see Fitzgerald, vol. i, pp. 190-194.