HE effect of William's attempt to jump upward was, as we have said, a positive surprise to him. He had fully expected that the act jumping upward would bring the attraction of gravitation into play again, or, more properly speaking, that to rise in the car he would be obliged to overcome the earth's attractive force. He consequently calculated to be able to jump no farther in the car than he would have been able to spring from the surface of the earth; that is to say, he expected to rise two or three feet, and to be then obliged to swim up the rest of the way to the top of the car.

But he was mistaken in believing that his upward progress would be checked by the attraction of gravitation. As the bodies in the car were