“Keep her away, Mr. Mark—­keep her away, you may, sir; we are well to windward of the channel.  Ay, that’ll do, Mr. Woolston—­that’s your beauty, sir.  Can’t you get a sight of them b’ys yourself, sir?”

“Not just yet, Bob, and so much the greater need that you should look out the sharper.  Give the ship plenty of room, and I’ll let her run down for the passage, square for the channel.”

Bob now ran aft, telling the mate he had better go on the forecastle himself and conn the ship through the passage, which was a place he did not like.  Mark was vexed that the change should be made just at that critical instant, but bounding forward, he was between the knight-heads in half a minute, looking out for the buoys.  At first, he could not see them; and then he most felt the imprudence of Bob’s quitting his post in such a critical instant.  In another minute, however, he found one; and presently the other came in sight, fearfully close, as, it now appeared to our young mariner, to its neighbour.  The position of the ship, nevertheless, was sufficiently to windward, leaving plenty of room to keep off in.  As soon as the ship was far enough ahead, Mark called out to Bob to put his helm hard up.  This was done, and away the Rancocus went, Mark watching her with the utmost vigilance, lest she should sheer a little too much to the one side or to the other.  He hardly breathed as the vessel glided down upon these two black sentinels, and, for an instant, he fancied the wind or the current had interfered with their positions.  It was now too late, however, to attempt any change, and Mark saw the ship surging onward on the swells of the ocean, which made their way thus far within the reefs, with a greater intensity of anxiety than he had ever before experienced in his life.  Away went the ship, and each time she settled in the water, our young man expected to hear her keel grating on the bottom, but it did not touch.  Presently the buoys were on her quarters, and then Mark knew that the danger of this one spot was passed!

The next step was to find the southern end of the outer ledge that formed the succeeding passage.  This was not done until the ship was close aboard of it.  A change had come over the spot within the last few hours, in consequence of the increase of wind, the water breaking all along the ledge, instead of on its end only; but Mark cared not for this, once certain he had found that end.  He was now half-way between his former anchorage and the crater, and he could distinguish the latter quite plainly.  But sail was necessary to carry the ship safely through the channel ahead, and Mark called to Bob to lash the helm a-midships after luffing up to his course, and to spring to the main-topmast staysail halliards, and help him hoist the sail.  This was soon done, and the new sail was got up, and the sheet hauled aft.  Next followed the mizen staysail, which was spread in the same manner.  Bob then flew to the wheel, and Mark to his knight-heads again.