As I walked aft I could tell, by the feel of the ship, that her race was nearly run--although I did not at that moment dream how very near to her end she was--and I paused abreast of the longboat to satisfy myself that she was quite ready for launching out through the wide gap that we had made in the bulwarks when cutting them away to provide material for the construction of the raft.  The gripes, I saw, had been cast off, and the boat was supported solely by her chocks, upon which she stood upright on the main hatchway.  Suddenly, stooping down, a small spot of bright light in the deep shadow under the boat caught my eye, and looking closer I saw that some careless rascal had omitted to put in the plug, and that the bright spot of light was caused by the sun shining down through the unplugged hole in the boat's bottom.  With a muttered objurgation of the fellow's carelessness, I climbed into the boat and, stooping down, sought for the plug.  I was seeking for perhaps two or three minutes before I found it, but as I was about to abandon the search, and hunt for a suitable cork out of which to cut another, my eye fell upon the missing plug, and I at once inserted it and proceeded to drive it tightly home.  I had just completed the job to my satisfaction when I felt the ship lurch heavily.  There was a sudden, violent rush and wash of water, and I sprang to my feet barely in time to see the boat caught up on the crest of a sea that came sweeping, green and solid, through the gap in the starboard bulwarks, and carried clear and clean out through the corresponding gap in the port side!  The longboat had launched herself; and before I could collect my senses, or lift a hand, I found myself adrift alone, some twenty fathoms to leeward of the doomed ship, and driving farther away from her every moment.