He stands so close to you that you can fairly feel the pulsation of his heart, but his voice sounds miles away. You swallow hard, the hardest you have ever swallowed, and you pinch your nose. You feel better. The far-away voice speaks again in your ear. "Three atmospheres," is all it says. The caisson shaft is no place for extended conversation. You descend in an express elevator car; in that bucket you just drop. You have all the eerie sensations that a Coney Island "novelty ride" might give you. There is a row of dim incandescents all the way down the smooth side of the shaft, and when you look you forget that this is vertical traction and think of an uptown subway tube as you see it recede from the rear of an express. A final manhole, the gate at the foot of the shaft and you stop abruptly. It seems as if you had almost bumped against the under side of China. "This is it," says the far-away voice. A timbered room, not larger than a parlor in a city flat and not near so high. A close and murky place, filled with a little company of men--shadowy humans of a real underworld there under the dull electric glow. "They're finding the footing for the shaft," says the voice. "We're on rock at last at 94 feet." * * * * * When the footings are finished and the caisson's edges have ceased to cut its path straight downward, that timbered construction will rest here far below the city for long ages. The sand-hogs will come out of their working chamber for the last time--it will be poured full of concrete, more solid than rock itself. The air pressure will be withdrawn--there is no longer mud or shifting sand for it to withhold. Then, section by section, the steel lining of the caisson shaft will be withdrawn, while concrete, tramped into place, makes the shaft a hidden monolith 100 feet or so in length. Upon the tops of all these monoliths a close grillage of steel beams will be laid; upon that grillage will be riveted the steel plates and columns of the bridge tower. The great structure is to have sure footing; these giant feet bind and clasp themselves throughout the years against the mighty river that has been conquered and humbled by the work of man. * * * * * "You should have been down in one of the boxes when they had to burn torches, before they got the electric light," says one of the bridge engineers. "I worked in one of those that we left under a stone tower of the Brooklyn Bridge. Now we're almost in clover. They even cool and dry the compressed air before we breathe it."