1 6 Original research a source of new industries. 



a wire, and an electric current then passed through 

 the wire, the needle moved and placed itself at right 

 angles to the current. This discovery, coupled with 

 the previous one of the electric conductivity of 

 metals, formed the indispensable basis of all our 

 electric telegraphs. 



Original research is very productive of new indus- 

 tries and inventions. The discoveries made by 

 Volta, Faraday, and many other investigators, have 

 led to the process of electro-plating, the use of 

 electric lights for lighthouses, and for ocean steam- 

 ships, and the great system of telegraphs. Those of 

 Davy, Wedgwood, and others, respecting the action 

 of light upon salts of silver, have resulted in the 

 modern processes of photography, which are now in 

 use almost everywhere. The discovery of zinc, by 

 Paracelsus, has been followed by the use of that 

 metal in galvanic batteries, and the great use of 

 " galvanized " iron for telegraph wires, for roofing, 

 and many other purposes. The discovery of nickel, 

 by Cronstedt, has led to the great modern use of 

 that metal in electro-plating, and to that of German 

 silver in the construction of electro-plated and other 

 articles. The discovery of chlorine, by Scheele, 

 ' formed the basis of nearly all our modern processes 

 i of bleaching cotton and other fabrics. The discovery 

 of gun-cotton and nitro-glycerine has led to the use 

 of those substances in blasting rocks and in warfare. 

 The discovery of oxygen, by Priestley, has enabled 

 us to understand and improve in a great number of 



