The full influence of Gilbert's work was not apparent for many years; not, in fact, until the discoveries and inventions of Volta, Galvani and Faraday showed the possibilities of utilizing electricity for practical purposes. Then the facts which Gilbert had established, and the discoveries built upon them afterward, were the basis of much of the work of those great men, and of the vast science of electrical engineering that resulted. The inventions made before the opening of the seventeenth century A. D., wonderful as they were, were quite widely separated in time, and seem to have been wholly the outcome of individual genius, and not the result or the indication of any widespread intellectual movement. But soon after it opened, the influence of printing in spreading knowledge became increasingly felt, and inventions began to succeed each other with rapidity, and to appear in places far apart. In the beginning of the seventeenth century, certain writings appeared in England that took great hold on the minds of thinking men, not only in England, but throughout Europe. The name of the author was Francis Bacon. It would not be within the scope of this book even to attempt to analyze the philosophy of Bacon, to differentiate between it and the philosophy of Aristotle or any other of the great thinkers of the world, or to try to trace directly the influence of Bacon's philosophy on his own time and on future times. It is obvious, however, that Bacon invented a system of inductive reasoning that assisted enormously to give precision to the thoughts of men in his own day, by convincing them of the necessity of first ascertaining exact facts, and then inferring correct conclusions from those facts. This seems to us an easy thing to do, looking at the matter in the light of our civilization. But it was not easy, though Bacon's high position gave him a prestige exceptional for a philosopher to possess; and this smoothed his way considerably. Men had not yet learned to think exactly. The efforts of even the great minds were of a groping character; and fanciful pictures made by the imagination seem to have intertwined themselves with facts, in such a way that correct inferences (except in mathematical operations) were hardly to be expected. Bacon insisted that every start on an intellectual expedition should be made from absolutely indisputable facts. The first effect of such teaching was to make men seek for facts. Not long afterward, we find that many men were making it the main business of their lives to seek for facts from Nature herself. This does not mean that men had not sought for facts before from Nature, or that Bacon alone is to be credited with the wonderful increase in the work of research and investigation that soon began.