It will be recalled that after great ceremonies, the Tube was begun simultaneously at the two terminating cities and proceeded through solid rock--low enough below the ocean floor to overcome the terrible pressure of the body of water over it, and yet close enough to the sea to overcome the intensity of subterranean heat. Needless to say, it was an extremely hazardous undertaking, despite the very careful surveys that had been made, for the little parties of workmen could never tell when they would strike a crack or an unexpected crevice that would let down upon them with a terrible rush, the waters of the Atlantic. But hazard is adventure, and as the two little groups of laborers dug toward each other, the eyes of the press followed them with more persistent interest than it has ever followed the daily toil of any man or group of men, either before or since. * * * * * Once the world was startled by the "extree-ee--" announcing that the English group had broken into an extinct volcano, whose upper end had apparently been sealed ages before, for it contained not water but air--curiously close and choking perhaps, but at least it was not the watery deluge of death. And then came the great discovery. No one who lived through that time will forget the thrill that quickened the pulse of mankind when the American group digging through a seam of old lava under what scientists call the "ancient ridge," broke into a sealed cavern which gleamed in the probing flashlights of the workers like the scintillating points of a thousand diamonds. But when they found the jeweled casket, through whose glass top they peered curiously down upon the white body of a beautiful woman, partly draped in the ripples of her heavy, red hair, the world gasped and wondered. As every school child knows, the casket was opened by curious scientists, who flocked into the tube from the length of the world, but at the first exposure to the air, the strange liquid that had protected the body vanished, leaving in the casket not the white figure, but only a crumbling mass of grey dust. But the questions that the finding of the cave had raised remained unanswered. [Illustration]