"All ready, Professor," was Nan's reply, as her hands tightened on the wheel.
Professor Krenner lifted the bugle to his lips and gave a clear, sonorous blast that served at the same time as a signal for starting and as a warning to any one who might be crossing the path at the foot of the hill.
Then he tipped the sled over the ridge of the hill and it started on its journey.
For a mere fraction of a second it seemed to poise itself for flight. Then it moved, slowly at first, but gathering speed with every second, until it seemed to be flying like an arrow from the bow.
There were delighted and at the same time somewhat fearful squeals from the girls, as the wind whistled past their ears while the sled flew on at a speed that quickly reached a mile a minute. They held on to each other for dear life, but Nan had no eyes or thought for anything except that shining ribbon of path.
She made the turn at the foot of the hill, the sled yielding to her slightest touch, and she only breathed freely when it shot out on the lake and there were no further obstacles to circumvent or fear.
On, on it went like a thing of life, as though it would never tire, and Nan's heart beat fast as she realized that she was going to make a better mark than she had ever done before.
But gradually the weight on the level surface began to tell, and the bobsled slowed up as though it were as reluctant as its passengers to find itself at its journey's end.
There was a chorus of joyous exclamations from the girls, as they rose to their feet and noted how far out they were on the lake.
"What a perfectly lovely sled!" exclaimed Rhoda Hammond. "I never had such a ride as that in my life."