turn completely over. The two girls screamed,, even Nan being frightened now.
"Oh, what is it? What is it?" cried Dorothy.
Then came a sharp crack. There was a sound as though a hundred pop-guns were being fired, and the boat slackened speed.
"Look!" cried Harry pointing ahead "Our sail has burst, Bert."
"No, it's the sheet rope—the main rope that holds the sail fast—that's broken," replied Bert. "Lucky it did, too, or we might have gone over. I was going to let go of it."
The ice-boat slid along a short distance, and then came to a stop. The sail, no longer held in place so as to catch the wind, was blowing and flapping, making snapping sounds like a line of clothes in a heavy wind.
"All right, girls, no danger now," called Bert, as he got out to make the flapping sail fast again. As he looked at the end of the broken rope he uttered a cry of surprise.
"Look here!" he called to Harry, "this rope has been cut!"
"Cut?"
