Mary begged to stand guard an hour or two longer; but Susan insisted that she was needed in the house, and reluctantly the girl descended from the platform.
Then Mark relieved Luke from duty, instructing him to first get his supper, and then, if the Indians remained inactive, to set about cleaning out the spring.
By this time the night had fully come, and Mark noted with apprehension that clouds were gathering in the sky. While the moon shone brightly it was as easy to guard against surprise as at noonday; but once that light was obscured, the enemy might creep up at a dozen places on the palisade without being detected.
"Two hours of blackness, and we are done for," Mark said to himself, with a sigh, and then, remembering what he had told Susan, he added, "We've got to take whatever comes, and the only manly way is to make the best of it. In case it is very dark to-night, Mary and Ellen must both stand watch with the rest of us."
The report of a musket interrupted his train of gloomy thoughts, and involuntarily he ducked his head when a bullet came singing over the fence so near that he felt the "wind" of it.
"You can't tempt me to shoot till I see something to fire at," he said, grimly, watching through the loophole at the underbrush which was merged by the shadows into one single mass of gloom, amid which not even a movement among the branches could be distinguished.
Two more shots, which caused him to wonder why the Abenakis were growing so active, and then he caught a glimpse of a faint spark in the thicket, which at first sight appeared to him like the glow from an Indian's pipe.
He had raised his musket, intending to fire at the bright spot, when it suddenly increased in size, and, while he stood speculating as to what it could be, a long tongue of flame leaped upward from branch to branch.
No need for speculation now, nor was it well that he stand very much longer on guard, for the terrible truth was all to plain.
The Abenakis had fired the woods, counting on burning the palisade, and thus giving them free entrance for the bloody business upon which they had come.