"If the snowball hits them, there will be a smash-up!" cried Roger.
"And that is just what is going to happen, I fear," answered Dave.
As the ice-boat came closer the boys on the hill saw that it contained four persons, two cadets and two young ladies. The latter were evidently guests, for they sat in the stern and took no part in handling the craft.
Dave set up a loud cry of warning and his chums joined in. But if those on the ice-boat heard, they paid no heed. On and on they came, heading for the very spot for which the great snowball, now all of six feet in diameter, was shooting.
"The ice is full of holes, maybe the snowball will drop into one of them," said Phil. But this was not to be. The snowball kept straight on, until it and the ice-boat were less than a hundred feet apart.
It was then that one of the cadets on the craft saw the peril and uttered a cry of alarm. He tried to bring the ice-boat around, and his fellow-student aided him. But it was too late, and in a few seconds more the big snowball hit the craft, bowled it over, and sent it spinning along the ice toward some of the largest of the air-holes.
"They are going into the water!" gasped Roger.
"Come on--let us see if we can help them!" returned Dave, and plunged down the hill. He took the course the big snowball had taken, and his chums came after him. More than once they fell, but picked themselves up quickly and kept on until the ice was gained. At the edge they came to a halt, for the air-holes told them plainly of the danger ahead.
"There they go--into the water!" cried Dave, and waiting no longer, he ran out on the ice, picking his way between the air-holes as best he could. Several times the ice cracked beneath his weight, but he did not turn back. He felt that the occupants of the ice-boat were in peril of their lives and that in a measure he was responsible for this crisis.
The river at this point was all of a hundred yards wide and the accident had occurred close to the farther side. The ice-boat had been sent to where two air-holes were close together, and the weight of the craft and its occupants had caused it to crack the ice, and it now rested half in and half out of the water. One of the cadets and one of the young ladies had been flung off to a safe place, but the other pair were clinging desperately to the framework.