orbit, and was forced to conclude that some inherent energy, perhaps an angel, perpetually acted to keep it moving. Galileo's law announces that if it is once set in motion it will continue to move until some impressed and extraneous force causes it to stop. Motion is as ‘natural’ as rest, therefore. It happens that on the earth there is no body moving under the action of no force. Falling bodies, projectiles, and the like, are perpetually attracted by the earth's mass, continually retarded by the resistance of the air. It required abstract philosophical reasoning to determine how such bodies would move were the impressed forces removed, and it is this reasoning that is Galileo's chief title to enduring fame. In this respect he changed the whole thought of the world. His telescopic discoveries might have been made by others. There was no man in Italy besides himself who could have founded the new science of mechanics.
The new laws of motion were expounded to the students of Pisa with fire and eloquence. The theories of Aristotle and of his followers were treated with scorn and contempt. In his zeal for the truth Galileo branded the scientific errors of his colleagues almost as if they had been moral faults. His asperity laid the foundation of enmities that followed him throughout the whole of his life and led to his ruin. It is as true of Galileo as of Roger Bacon that his character was his fate.
How the strictures of Galileo were received by the exasperated Aristotelians may be imagined. If his experiments were to be believed, the words of Aristotle were false. If the philosophy of Aristotle were false in one part it might be false in all. The experiments must therefore be denied, and their author discredited. It is recorded that the experiments were, in fact, denied. The facts of experience were met
