392 ELEMENTARY LESSONS ON [CHAP. XL 



production of chromatic effects by electrolysing a solu- 

 tion of lead in caustic soda, is applied in Nuremberg to 

 ornament metallic toys. The author of these Lessons 

 has observed that when Nobili's rings are made in a 

 magnetic field they are no longer circular, the depositing 

 currents being drawn aside in a manner which could be 

 predicted from the observed action of magnets on con- 

 ductors carrying currents. 



