14 nature's 



that I found described, if it were possible. 

 The bottom of my mother's wash-boiler was 

 copper, and just the thing to make the square 

 plates of copper to match the zinc ones, made 

 from another piece of domestic f urn it u re- 

 used under the stove. I shocked my mother 

 twice first with the voltaic pile that I had 

 constructed, and again when she found out 

 where the metal plates came from. The 

 sequel to all this was but why dwell upon a 

 painful subject! 



Galvanism and voltaic electricity are the 

 same. Volta was the first to construct what 

 is termed the galvanic battery. The unit of 

 electrical pressure or electromotive force is 

 called the volt, and takes its name from Volta, 

 the great founder of the science of galvanic 

 or voltaic electricity. From this pile con- 

 structed by Volta innumerable forms of bat- 

 teries have been devised. The evolution of 

 the galvanic battery in all its forms, from 

 Volta to the present day, would fill a large 

 volume if all were described. 



The discoveries of Michael Faraday (1791- 

 1867), the distinguished English chemist and 

 physicist, led to another phase of the science 

 that has revolutionized modern life. Faraday 

 made an experiment that contains the germ of 

 all forms of the modern dynamo, which is a 

 machine of comparatively recent development. 

 He found that by winding a piece of insulated 



