To the student of the relations between Christianity and science it must appear doubtful whether the criticism or the other consequences which the men of science had to meet from the Church was harmful to their work. The early naturalists, like the Greeks whom they followed, were greatly given to speculations concerning the processes of Nature, which, though interesting, were unprofitable. They also showed a curious tendency to mingle their scientific speculations with ancient and base superstitions. They were often given to the absurdity commonly known as the "black art," or witchcraft, and held to the preposterous notions of the astrologists. Even the immortal astronomer Kepler, who lived in the sixteenth century, was a professional astrologer, and still held to the notion that the stars determined the destiny of men. Many other of the famous inquirers in those years which ushered in modern science believed in witchcraft. Thus for a time natural learning was in a way associated with ancient and pernicious beliefs which the Church was seeking to overthrow. One result of the clerical opposition to the advancement of science was that its votaries were driven to prove every step which led to their conclusions. They were forced to abandon the loose speculation of their intellectual guides, the Greeks, and to betake themselves to observation. Thus a part of the laborious fact-gathering habit on which the modern advance of science has absolutely depended was due to the care which men had to exercise in face of the religious authorities. In our own time, in the latter part of the nineteenth century, the conflict between the religious authority and the men of science has practically ceased. Even the Roman Church permits almost everywhere an untrammelled teaching of the established learning to which it was at one time opposed. Men have come to see that all truth is accordant, and that religion has nothing to fear from the faithful and devoted study of Nature. The advance of science in general in modern times has been greatly due to the development of mechanical inventions. Among the ancients, the tools which served in the arts were few in number, and these of exceeding simplicity. So far as we can ascertain, in the five hundred years during which the Greeks were in their intellectual vigour, not more than half a dozen new machines were invented, and these were exceedingly simple. The fact seems to be that a talent for mechanical invention is mainly limited to the peoples of France, Germany, and of the English-speaking folk. The first advances in these contrivances were made in those countries, and all our considerable gains have come from their people. Thus, while the spirit of science in general is clearly limited to the Aryan folk, that particular part of the motive which leads to the invention of tools is restricted to western and northern Europe, to the people to whom we give the name of Teutonic.