Page:Popular Science Monthly Volume 48.djvu/782

702 in its race, is transmitted to its puppies when these are secluded from all chance of instruction or imitation. The students who make natural selection the be-all and the end-all of evolution assume that it seizes upon favoring variations, even the slightest, as they appear. Whether these variations are indebted to parental experience directly transmitted is a question which only careful experiment can decide. The significance of the work when interpreted, the charm of coming upon results wholly new, must do much to extend interest in natural history. Often that interest comes early to a weary end in the dust of common-place and meaningless adding of shell to shell and butterfly to butterfly.



these days when many wonders are being accomplished through electricity, and greater ones are constantly expected, it is interesting to glance backward into the times when the lodestone and the sulphur globe stood for all that was known about this mysterious form of energy. Such a glance is afforded us by Mr. Park Benjamin's popular history of the advance of knowledge in this subject. Our author has ranged far and wide to gather his material. He has laid under contribution the works of those early philosophers who took all knowledge for their province, the Greek and Roman classics, the results of modern investigation into the old civilization of Phoenicia, Egypt, and even of people of prehistoric epochs, the Norse histories, the ancient writings of the Chinese and Arabs, the treatises of the fathers of the Church, the works of mediæval monks, magicians, cosmographers, and navigators, etc. The significance of the title he has chosen lies in the fact that he has aimed not so much to chronicle the laying of fact upon fact in the building of the present science of electricity as to show how the progress of the human intellect is indicated by the way in which it has grappled with and overcome the problems in this field that have successively presented themselves. He shows how mythology, which was the world's resource for explaining strange phenomena when the lodestone became known, gave way to philosophy, and how philosophy in turn yielded its sway to science. Who first discovered that a freely suspended magnet will point north and south our author does not undertake to say, but from a careful examination of the allusions to the use of the compass in Chinese writings, and a consideration of the Chinese character, he is convinced that it was not the Chinese. For several centuries the development of the compass was the only advance in the field of magnetism made by Arabs or Northmen or the peoples of western Europe. Roger Bacon made some interesting observations on the compass, but it appears that the French engineer, Peter Perigrinus, of whom Bacon speaks in glowing terms, made an experimental study of this instrument, which was far more fruitful than any earlier efforts. Among other things he revealed the law