ELECTRICITY DrRIXG THE NINETEENTH CENTURY. 



By Prof, Elihu Thomson. 



The great importance which clectricit}- has attained in many depart- 

 ments of human activity is so constantly evident that we have difficulty 

 in realizing how short is the time which has been occupied in its 

 development. The latter half of the nineteenth century must ever 

 remain memorable, not only for the great advances in nearly all the 

 useful arts, but for the pecidiarly rapid electric progress, and the pro- 

 found effect which it has had upon the lives and business of the peo- 

 ple. In the preceding century we find no evidences of the applica- 

 tion of electricity to any useful purpose. Few of the more impor- 

 tant principles of the science were then known. Franklin's invention 

 of the lightning rod was not intended to utilize electric force, but to 

 guard life and property from the perils of the thunderstorm. The 

 numerous instructive experiments in frictional electricity, the first 

 known form of electric manifestation except lightning, made clear 

 certain principles, such as conduction and insulation, and served to 

 distinguish the two opposite electric conditions known as positive and 

 negative. Franklin's kite experiment confirmed the long-suspected 

 identit}' of lightning and electric sparks. It was«not, however, until 

 the discovery by Alexander Volta in 1799 of his pile, or battery, that 

 electricity could take its place as an agent of practical value. Volta, 

 when he made this great discovery, was following the work of Gal- 

 vani, begun in 1786. But Galvani in his experiments mistook the effect 

 for the cause and so missed making the unique demonstration that two 

 different metals immersed in a solution could set up an electric current. 

 Volta, a professor in the University of Pavia and a foreign member of 

 the Royal Society of England, communicated his discovery to the 

 president of the society in March, 1800, and brought to the notice of 

 the world the first means for obtaining a steady flow of electricity. 

 Before this event electric energy had been known to the experimenter 

 in pretty effects of attraction and repulsion of light objects, in fitful 

 flashes of insignificant power, or as it appeared in nature, in the fearful 

 bursts of energy during a thunderstorm, uncontrolled and eiTatic. The 



' Copyright, 1901, by The Sun Printing and Pubhshing Association. Reprinted, by 

 special permission, from the Sun, New York, February 10, 1901. 



SM 1900 24 ^^^ 



