The Panama Canal is the greatest engineering project of all history. There is more than the patriotic prejudice of a people proud of their own achievements behind this assertion. Men of all nations concede it without question, and felicitate the United States upon the remarkable success with which it has been carried out. So distinguished an authority as the Rt. Hon. James Bryce, late British ambassador to Washington, and a man not less famous in the world of letters than successful in the field of diplomacy, declared before the National Geographic Society that not only is the Panama Canal the greatest undertaking of the past or the present but that even the future seems destined never to offer any land-dividing, world-uniting project comparable to it in magnitude or consequence.

We are told that the excavations total 232,000,000 cubic yards; that the Gatun Dam contains 21,000,000 cubic yards of material; and that the locks and spillways required the laying of some 4,500,000 cubic yards of concrete. But if one is to realize the meaning of this he must get out of the realm of cubic yards and into the region of concrete comparisons. Every one is familiar with the size and shape of the Washington Monument. With its base of 55 feet square and its height of 555 feet, it is one of the most imposing of all the hand reared structures of the earth. Yet the material excavated from the big waterway at Panama represents 5,840 such solid-built shafts. Placed in a row with base touching base they would traverse the entire Isthmus and reach 10 miles beyond deep water in the two oceans at Panama. Placed in a square with base touching base they would cover an area of 475 acres. If all the material were placed in one solid shaft with a base as large as the average city block, it would tower nearly 100,000 feet in the air.

Another illustration of the magnitude of the quantity of material excavated at Panama may be had from a comparison with the pyramid of Cheops, of which noble pile some one has said that "All things fear Time, but Time fears only Cheops." We are told that it required a hundred thousand men 10 years to make ready for the building of that great structure, and 20 years more to build it. There were times at Panama when, in 26 working days, more material was removed from the canal than was required to build Cheops, and from first to last the Americans removed material enough to build sixty-odd pyramids such as Cheops. Were it all placed in one such structure, with a base as large as that of Cheops, the apex would tower higher into the sky than the loftiest mountain on the face of the earth.

Still another way of arriving at a true conception of the work of digging the big waterway is to consider that enough material had to be removed by the Americans to make a tunnel through the earth at the equator more than 12 feet square.

But perhaps the comparison that will best illustrate the immensity of the task of digging the ditch is that of the big Lidgerwood dirt car, on which so much of the spoil has been hauled away. Each car holds about 20 cubic yards of dirt, and 21 cars make a train. The material removed from the canal would fill a string of these cars reaching about three and a half times around the earth, and it would take a string of Panama Railroad engines reaching almost from New York to Honolulu to move them.

Yet all these comparisons have taken account of the excavations only. The construction of the Panama Canal represents much besides digging a ditch, for there were some immense structures to erect. Principal among these, so far as magnitude is concerned, was the Gatun Dam, that big ridge of earth a mile and a half long, half a mile thick at the base, and 105 feet high. It contains some 21,000,000 cubic yards of material, enough to build more than 500 solid shafts like the Washington Monument. Then there was the dam at Pedro Miguel—"Peter Magill," as the irreverent boys of Panama christened it—and another at Miraflores, each of them small in comparison with the great embankment at Gatun, but together containing as much material as 70 solid shafts like our Washington Monument.

Besides these structures there still remain the locks and spillways, with their four and a half million cubic yards of concrete and their hundreds and thousands of tons of steel.

With all these astonishing comparisons in mind, is it strange that the digging of the Panama Canal is the world's greatest engineering project? Are they not enough to stamp it as the greatest single achievement in human history? Yet even they, pregnant of meaning as they are, fail to reveal the full and true proportions of the work of our illustrious army of canal diggers. They tell nothing of the difficulties which were overcome—difficulties before which the bravest spirit might have quailed.

When the engineers laid out the present project, they calculated that 103,000,000 cubic yards of material would have to be excavated, and predicted that the canal diggers would remove that much in nine years. Since that time the amount of material to be taken out has increased from one cause or another until it now stands at more than double the original estimate. At one time there was an increase for widening the Culebra Cut by 50 per cent. At another time there was an increase to take care of the 225 acres of slides that were pouring into the big ditch like glaciers. At still another time there was an increase for the creation of a small lake between the locks at Pedro Miguel and Miraflores. At yet another time it was found that the Chagres River and the currents of the Atlantic and the Pacific Oceans were depositing large quantities of silt and mud in the canal, and this again raised the total amount of material to be excavated. But none of these unforeseen obstacles and additional burdens dismayed the engineers. They simply attacked their problem with renewed zeal and quickened energy, with the result that they excavated in seven years of actual operations more than twice as much material as they were expected to excavate in nine years. In other words, the material to be removed was increased 125 per cent and yet the canal was opened at least 12 months ahead of the time predicted.

How this unprecedented efficiency was developed forms in itself a remarkable story of achievement. The engineers met with insistent demands that they "make the dirt fly." The people had seen many months of preparation, but they had no patience with that; they wanted to see the ditch begin to deepen. It was a critical stage in the history of the project. If the dirt should fail to fly public sentiment would turn away from the canal.

So John F. Stevens addressed himself to making it fly. Before he left he had brought the monthly output almost up to the million yard mark. When that mark was passed the President of the United States, on behalf of himself and the nation, sent a congratulatory message to the canal army. Many people asserted that it was nothing but a burst of speed; but the canal diggers squared themselves for a still higher record. They forced up the mark to two million a month, and straightway used that as a rallying point from which to charge the heights three million. Once again the standard was raised; "four million" became the slogan. Wherever that slogan was flashed upon a Y.M.C.A. stereoptican screen there was cheering—cheering that expressed a determined purpose. Finally, when March, 1909, came around all hands went to work with set jaws, and for the only time in the history of the world, there was excavated on a single project, 4,000,000 cubic yards of material in one month.

With the dirt moving, came the question of the cost of making it fly. By eliminating a bit of lost motion here and taking up a bit of waste there, even with the price of skilled labor fully 50 per cent higher on the Isthmus than in the States, unit costs were sent down to surprisingly low levels. For instance, in 1908 it was costing 11¹/₂ cents a cubic yard to operate a steam shovel; in 1911 this had been forced down to 8⁷/₈ cents a yard. In 1908 more than 18¹/₂ cents were expended to haul a cubic yard of spoil 8 miles; in 1911 a cubic yard was hauled 12 miles for a little more than 15¹/₅ cents.

Some of the efficiency results were astonishing. To illustrate: One would think that the working power of a ton of dynamite would be as great at one time as another; and yet the average ton of dynamite in 1911 did just twice as much work as in 1908. No less than $50,000 a month was saved by shaking out cement bags.

It was this wonderful efficiency that enabled the United States to build the canal for $375,000,000 when without it the cost might have reached $600,000,000. In 1908, after the army had been going at regulation double-quick for a year, a board was appointed to estimate just how much material would have to be taken out, and how much it would cost. That board estimated that the project as then planned would require the excavation of 135,000,000 cubic yards of material, and that the total cost of the canal as then contemplated would be $375,000,000. Also it was estimated that the canal would be completed by January 1, 1915. After that time the amount of material to be excavated was increased by 97,000,000 cubic yards, and yet so great was the efficiency developed that the savings effected permitted that great excess of material to be removed without the additional expense of a single penny above the estimates of 1908, and in less time than was forecast.

Although the difficulties that beset the canal diggers were such as engineers never before encountered, they were met and brushed aside, and all the world's engineering records were smashed into smithereens. It required 20 years to build the Suez Canal, through a comparatively dry and sandy region. When the work at Panama was at its height the United States was excavating the equivalent of a Suez Canal every 15 months. Likewise it required many years to complete the Manchester Ship Canal between Liverpool and Manchester, a distance of 35 miles. This canal cost so much more than was estimated that money was raised for its completion only with the greatest difficulty. Yet at Panama the Americans dug four duplicates of the Manchester Ship Canal in five years. All of this was done in spite of the fact that they had to work in a moist, hot, enervating climate where for nine months in a year the air seems filled with moisture to the point of saturation, and where, for more than half the length of the great ditch, the annual rainfall often amounts to as much as 10 feet—all of this falling in the nine months of the wet season.

A few comparisons outside of the construction itself will serve to illustrate the tremendous proportions of the work. Paper money was not handled at all in paying off the canal army. It took three days to pay off the force with American gold and Panaman silver. When pay day was over there had been given into the hands of the Americans, and thrown into the hats of the Spaniards and West Indian negroes, 1,600 pounds of gold and 24 tons of silver. When it is remembered that this performance was repeated every month for seven years, one may imagine the enormous outlay of money for labor.

The commissary also illustrates the magnitude of the work. Five million loaves of bread, a hundred thousand pounds of cheese, more than 9,000,000 pounds of meat, half a million pounds of poultry, more than a thousand carloads of ice, more than a million pounds of onions, half a million pounds of butter—these are some of the items handled in a single year.

Wherever one turns he finds things which furnish collateral evidence of the magnitude of the work. The Sanitary Department used each year 150,000 gallons of mosquito oil, distributed thousands of pounds of quinine, cut and burned millions of square yards of brush, and spent half a million dollars for hospital maintenance.

No other great engineering project has allowed such a remarkable "margin of safety"—the engineering term for doing things better than they need to be done. The engineers who dug the canal took nothing for granted. No rule of physics was so plain or so obvious as to escape actual physical proof before its acceptance, when such proof was possible. No one who knows how the engineers approached the subject, how they resolved every doubt on the side of safety, and how they kept so far away from the danger line as actually to make their precaution seem excessive can doubt that the Panama Canal will go down in history as the most thorough as well as the most extensive piece of engineering in the world.