CHAPTER 78. Cistern and Buckets. Nimble as a cat, Tashtego mounts aloft; and without altering his erect posture, runs straight out upon the overhanging mainyard-arm, to the part where it exactly projects over the hoisted Tun. He has carried with him a light tackle called a whip, consisting of only two parts, travelling through a single-sheaved block. Securing this block, so that it hangs down from the yard-arm, he swings one end of the rope, till it is caught and firmly held by a hand on deck. Then, hand-over-hand, down the other part, the Indian drops through the air, till