Fortunately for electrical science, and for that matter all sciences, about this time the influence of Lord Bacon’s Inductive Philosophy began to be felt by investigators and scientific men. Before that, the causes of natural phenomena had not been backed up by repeated experiments amounting to practical proofs, but had been accounted for, if at all, by sheer guesses or whimsical reasons. Bacon’s method introduced hard, cold, constant experiment as the only sure means of finding out exactly the causes of natural phenomena; and not only this, but the necessity of series upon series of experiments, each based upon the results of the former, and so continuing, link by link, till, from a comparison of the whole, some general principle or truth could be drawn that applied to all. This _inductive_ method of scientific research gave great impetus to the study of every branch of science, and especially to the unfolding of infallible and practical laws governing the phenomena of nature. For very many years electrical experiments followed the lines laid down by Dr. Gilbert; that is, the finding of substances that could be excited or electrified by friction. By and by such substances came to be called _electrics_, and it became a part of the crude electrical science of the time to compute the force with which these electrics, when excited, attracted or repelled other substances near them. Among the ablest of these investigators were Robert Boyle, author of “Experiments on the Origin of Electricity,” Sir Isaac Newton, Otto von Guericke, and Francis Hawksbee, the last of whom communicated his experiments to the English Royal Society in 1705. Otto von Guericke used a hard roll of sulphur as an electric. He caused it to revolve rapidly while he rubbed or excited it with his hand. Newton and Hawksbee used a revolving glass globe in the same way, and thus became the parents of the modern and better equipped electrical machine used for school purposes.