The great Chinese wall has been celebrated in all history as one of man’s most gigantic efforts. It is 1500 miles long and would reach from San Francisco to St. Louis. But the rock and dirt taken from the Panama Canal would build a wall as high and thick as the Chinese wonder, 2500 miles long and reach from San Francisco to New York in a bee-line. [Illustration: WHAT THE PANAMA CONCRETE WOULD DO] We cross thousands of miles of ocean to see the great Pyramid of Cheops, one of the Seven Wonders of the ancient world. But the “spoil” taken from the canal prism would build sixty-three such pyramids which put in a row would fill Broadway from the Battery to Harlem, or a distance of nine miles. The Panama Canal is but fifty miles long, but if we could imagine the United States as perfectly level, the amount of excavation done at Panama would dig a canal ten feet deep and fifty-five feet wide across the United States at its broadest part. New York City boasts of its great Pennsylvania terminal, and its sky-piercing Woolworth Building; Washington is proud of its towering Washington Monument, the White House and the buildings adjacent thereto. But the concrete used in the locks and dams of the canal would make a pyramid 400 feet high, covering the great railway station; the material taken from Culebra cut alone would make a pyramid topping the Woolworth tower by 100 feet, and covering the city from Chambers to Fulton Street, and from the City Hall to West Broadway; while the total soil excavated in the Canal Zone would form a pyramid 4200 feet or four fifths of a mile high, and of equal base line obliterating not only the Washington Monument but the White House, Treasury, the State, War and Navy Buildings and the finest part of official Washington as well. Jules Verne once, in imagination, drove a tunnel through the center of the earth, but the little cylindrical tubes drilled for the dynamite cartridges on “the line” (as people at Panama refer to the Canal Zone) would, if placed end to end, pierce this great globe of ours from side to side; while the dirt cars that have carried off the material would, if made up in one train, reach four times around the world. [Illustration: _Courtesy Scientific American_ PROPORTIONS OF SOME OF THE CANAL WORK]