A HISTORY OF SCIENCE 



''running down." Numerous experimenters, there- 

 fore, set about devising a satisfactory battery, and 

 when, in 1836, John Frederick Daniell produced the 

 cell that bears his name, his invention was epoch- 

 making in the history of electrical progress. The 

 Royal Society considered it of sufficient importance 

 to bestow the Copley medal upon the inventor, whose 

 device is the direct parent of all modern galvanic cells. 

 From the time of the advent of the Daniell cell ex- 

 periments in electricity were rendered comparatively 

 easy. In the mean while, however, another great dis- 

 covery was made. 



ELECTRICITY AND MAGNETISM 



For many years there had been a growing suspicion, 

 amounting in many instances to belief in the close re- 

 lationship existing between electricity and magnetism. 

 Before the winter of 1815, however, it was a belief 

 that was surmised but not demonstrated. But in that 

 year it occurred to Jean Christian Oersted, of Den- 

 mark, to pass a current of electricity through a wire 

 held parallel with, but not quite touching, a suspended 

 magnetic needle. The needle was instantly deflected 

 and swung out of its position. 



"The first experiments in connection with the sub- 

 ject which I am undertaking to explain," wrote Oer- 

 sted, "were made during the course of lectures which 

 I held last winter on electricity and magnetism. From 

 those experiments it appeared that the magnetic needle 

 could be moved from its position by means of a gal- 

 vanic battery one with a closed galvanic circuit. 

 Since, however, those experiments were made with an 



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