ix SCIENTIFIC MOTIVE 241 



Italian, discovered in 1800 his voltaic pile by means 

 of which a continuous current of electricity can be 

 produced. In 1819 Hans Christian Oersted, a professor 

 at the University of Copenhagen, observed that when 

 a wire conveying an electric current was placed length- 

 ways over a compass needle, the needle turned aside 

 from it. The discovery was made accidentally in the 

 course of a lecture, but, as in many other instances in 

 the history of science, " such accidents only meet 

 persons who deserve them." The principle of the 

 relationship thus disclosed between electricity and 

 magnetism was worked out in detail by Ampere, the 

 leading French investigator of electricity ; and he 

 suggested that the effect of the current might be used 

 for signalling at a distance. Two German men of 

 science Gauss and Weber established this means of 

 communication upon a short line in Gottingen in 

 1833, and the first magneto-electric telegraph thus came 

 into being out of laboratory experiment and mathe- 

 matical analysis. 



When Oersted published the results of his observations 

 of the influence of an electric current upon a magnet, 

 no one supposed that they could have an important 

 practical value, yet upon his simple experiment the 

 system of electric telegraphy was based. By sending 

 an electric current through a wire, a compass needle 

 can be deflected to one side or the other at the distant 

 end, and the signals thus received can be translated 

 into messages. 



Oersted would never have made his great discovery of the 

 action of galvanic currents on magnets had he stopped in his 

 researches to consider in what manner they could possibly be 

 turned to practical account ; and so we should not now be able 

 to boast of the wonders done by the electric telegraphs. Indeed, 

 no great law in Natural Philosophy has ever been disco vered for 



G.D. 



