power of Satan. Every form of disease might be produced by Satan or his agents, the witches; and none of the infirmities to which Luther was liable were natural; but his earache was peculiarly diabolical. Hail, thunder, and plagues, are all the direct consequence of the intervention of spirits. Many of those persons who were supposed to have committed suicide had in reality been seized by the devil and strangled by him, as the traveler is strangled by the robber. The devil could transport men through the air. He could beget children; and Luther himself had come in contact with one of them. An intense love of children was one of the most amiable characteristics of the great Reformer; but on this occasion he most earnestly recommended the reputed relatives to throw the child into the river, in order to free their house from the presence of the devil. As a natural consequence of these modes of thought, witchcraft did not present the slightest improbability to his mind. In strict accordance with the spirit of his age, he continually asserted the existence and frequency of the crime, and emphatically proclaimed the duty of burning witches."
We see what a loving obedience to the word of God led Luther to recommend. That this spirit has died out, is wholly due to the advancement of science and rationalism, and not to any change in the religious spirit per se, or to any different interpretation of the Bible. The witchcraft is there, as it was in the days of Luther, and the injunction not to suffer witches to live is there, and neither has been explained any better than it was in the middle ages. But the researches of the investigators of Nature have gradually driven these notions out of the minds of men, and stamped them with the opprobrium of absurdities.
IN his late work, "Recent Advances in Physical Science," Prof. Tait, of the University of Edinburgh, has attempted a history of dynamical science, or rather of the doctrine of the conservation of energy. Though this great doctrine is recent in its completer development, Prof. Tait holds that it is implied in Newton's laws of motion, and that Newton only failed to grasp it in its modern form for lack of certain experiments. Where Newton broke down, there the subject remained for more than a hundred years, no physicist appearing w r ho could take up the research at that point and carry it on. Prof. Tait says that "what Newton really w anted was to know what becomes of work when it is spent in friction." The experiments thus needed to open the way to a new era in the doctrine of forces were supplied