8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 76 



experiments. He also made a number of experiments himself and suc- 

 ceeded in liquifying chlorine gas for which he was elected to a Fel- 

 lowship in the Royal Institution in 1824. Following up Oersted's 

 and Ampere's work, he endeavored to find the relation between 

 electricity and magnetism. Finally on Oct. 17, 1831, he made the 

 experiment of moving a permanent bar magnet in and out of a coil 

 of wire connected to a galvanometer. This generated electricity in 

 the coil which deflected the galvanometer needle. A few days after, 

 Oct. 28, 1831, he mounted a copper disk on a shaft so that the disk 

 could be rotated between the poles of a permanent horseshoe magnet. 



Faraday's Dynamo, 1831. 



Faraday discovered that electricity could be generated by means of a 

 permanent magnet. This principle is used in all dynamos. 



The shaft and edge of the disk were connected by brushes and wires 

 to a galvanometer, the needle of which was deflected as the disk was 

 rotated. A paper on his invention was read before the Royal Society 

 on November 24, 1831, which appeared in printed form in January, 

 1832. 



Faraday did not develop his invention any further, being satisfied, 

 as in all his work, in pure research. His was a notable invention but 

 it remained for others to make it practicable. Hippolyte Pixii, a 

 Frenchman, made a dynamo in 1832 consisting of a permanent horse- 

 shoe magnet which could be rotated between two wire bobbins 

 mounted on a soft iron core. The wires from the bobbins were con- 



