PRESIDENTIAL ADDRESS, S.T.E. 1874. 227 



as valuable as those to be had by electro- 

 meter. 



I should speak also of the subject of atmospheric 

 electricity. The electric telegraph brings this 

 phenomenon into connection with terrestrial mag- 

 netism, with earth currents, and, through them, 

 with aurora borcalis, in a manner for which ob- 

 servations made before the time of the electric 

 telegraph, or without the aid of the electric tele- 

 graph, had not given us any data whatever. 

 Scientific observations on terrestrial magnetism, 

 and on the aurora, and on atmospheric electricity, 

 had shown a connection between the aurora and 

 terrestrial magnetism in the shape of the disturb- 

 ances that I have alluded to at a time of magnetic 

 storm ; but no connection between magnetic 

 storms and atmospheric electricity, thunderstorms, 

 or generally the state of the weather what is 

 commonly called meteorology has yet been dis- 

 covered. There is just one common link connect- 

 ing these phenomena and those exhibited in the 

 electric telegraph. A telegraphic line an air line 

 more particularly, but a submarine line also 



Q 2 



