154 The Evolution of Electric and Magnetic Physics. 



have prepared the human mind to usher and reveal the 

 mysteries of Nature. 



The renascent dawn of the scientific era, or the age of 

 objective investigation a method of study that had almost 

 become extinguished with the ruin of Alexandria threw 

 open the pathways of physical research and brought the 

 first recognition of electricity to light. The commence- 

 ment of the seventeenth century was noted for its discov- 

 eries in electric and magnetic science. Thales lived about 

 six hundred years before Christ, and Dr. Gilbert, of Col- 

 chester, christened and presented the new science _ to the 

 world in his celebrated book De Magnete, published in 1600. 



The early history of magnetism tells a similar tale. The 

 attracting power of the loadstone was known to the Greeks, 

 and the knowledge of the directive property of the suspend- 

 ed needle or mariner's compass is said to have been pos- 

 sessed by the Chinese long before the Christian era ; but the 

 first published researches in the subject were by Norman 

 and Boroughs, of London, in 1580. Just at this time Fran- 

 cis Bacon, the champion of experimental science and in- 

 ductive philosophy, was preparing those works that have 

 made his name immortal. The time was ripe for the new 

 thought, for human intelligence at length stood ready to 

 burst through the trammels that inthralled it, and to vin- 

 dicate its prerogative to judge according to evidence. 



Slowly, and against much opposition, experimental physics 

 developed the sciences of magnetism and electricity. For 

 two hundred years the two sciences stood entirely apart ; 

 their intimate relationship was perhaps only suggested in 

 the poet's fancy, nor was it scientifically demonstrated till 

 1820. Even at the present moment, intimate though we 

 recognize that relationship to be, the line that separates and 

 the tie that unites them are still matters of speculation that 

 the future must resolve. 



The earlier progress was shown by electricity. Von Gue- 

 ricke, in 1672, made the first electrical machine out of a 

 globe of sulphur rotated by hand, and produced with it the 

 first artificial electric spark. The sound accompanying the 

 spark was also noticed by von Guericke. Newton three 

 years later improved upon this machine by substituting a 

 glass sphere' for the globe in place of sulphur. Now that a 

 simple generator of electricity was capable of being made, 

 experiments became more common and facts accumulated. 

 Gray and Wheeler in particular, between 1720 and 1736, 



