A GLASS OF WATER. 66 1 



Let me here allude to those stupendous processes, the manufactures 

 of sulphuric acid and of soda. To sketch the influence of chemistry 

 upon life would carry us too far. Glass and soap are better to-day, 

 and, despite their hundred-fold increased consumption, no dearer than 

 in former times. Chlorine, as a bleaching agent, in place of the sun, 

 has restored to agriculture thousands of acres of meadow-land. 



But the powerful impulse carried also the kindred sciences. The 

 Italian physician Galvani accidentally noticed the convulsions of a 

 frog recently killed, whenever he touched him with two metals in con- 

 tact with each other. This observation became the starting-point of 

 the electric telegraph. The experiments of Volta resulted in the pile 

 named after him. Two heterogeneous metals, such as zinc and copper, 

 are immersed in a glass of water, to which a few drops of sulphuric 

 acid have been added ; both metals we connect by means of a long 

 wire, and then we find the wire possessed of a new force which can 

 transmit a motion through the distance of a hundred miles and over. 

 For a long time the voltaic pile had been the subject of unsuccessful 

 experiments for the purpose of finding its relation to the magnet, to 

 which, on account of its poles, it bears a certain resemblance. One 

 day, Oersted, at a lecture in Copenhagen in 1819, noticed that a mag- 

 netic needle on his table was disturbed by a communicating wire that 

 happened to pass over it. He removed the wire, and the needle re- 

 sumed its polar direction ; he then replaced the wire, and the needle 

 again turned aside. Electro-magnetism was discovered. At once he 

 recognized the immense bearing of the phenomenon, repeated the ex- 

 periment in presence of the magistrate, a notary public, and other wit- 

 nesses, and made a Latin affidavit ; this places his name, for all time 

 to come, among the benefactors of the human race. The advantage of 

 his invention is enjoyed by all of us who daily read telegrams from 

 distant parts of the world as if this rapid transmission of news were a 

 matter of course. The wonder has become a fact of daily occurrence ; 

 it rises with us and accompanies us through the day. Do you ever 

 consider that, without this discovery of Oersted, the telegraph would 

 not exist ? 



We place thirty or forty glasses of water in adjacency, each con- 

 taining a plate of zinc and one of copper, together with a small quan- 

 tity of sulphuric acid ; we join the vessels by means of metallic wires 

 soldered to the opposite plates, and connect the two extreme plates of 

 the series with the ground, the extreme zinc plate by a short wire, the 

 last copper by, say, a hundred-mile wire. A slight pressure of the finger 

 upon a knob supported by a spring, and a dash or dot is produced a 

 hundred miles away; thought is transmitted to that distance by the 

 electric current ; it makes its own record, the recipient needs simply to 

 read off the marks. And through still greater distances it may be 

 flashed by what is termed a relay, so that there is no greater difficulty 

 in forwarding a dispatch from New York to San Francisco than from 

 New York to Boston. 



