That two men should handle a stone so heavy, even swinging in the scissors, may appear strange to the inexpert. These must bear in mind the great density of the water of the sea, and the surprising results of transplantation to that medium. To understand a little what these are, and how a man’s weight, so far from being an encumbrance, is the very ground of his agility, was the chief lesson of my submarine experience. The knowledge came upon me by degrees. As I began to go forward with the hand of my estranged companion, a world of tumbled stones was visible, pillared with the weedy uprights of the staging: overhead, a flat roof of green: a little in front, the seawall, like an unfinished rampart. And presently in our upward progress, Bob motioned me to leap upon a stone; I looked to see if he were possibly in earnest, and he only signed to me the more imperiously. Now the block stood six feet high; it would have been quite a leap to me unencumbered; with the breast and back weights, and the twenty pounds upon each foot, and the staggering load of the helmet, the thing was out of reason. I laughed aloud in my tomb; and to prove to Bob how far he was astray, I gave a little impulse from my toes. Up I soared like a bird, my companion soaring at my side.