APPENDIX. 65 



spring is used to withdraw the armature from the 

 magnet, where it remains until the next magnetic 

 impulse arrives. 



NOTE Y, PAGE 54. 



These beautiful and now appropriate verses ap- 

 peared in a country newspaper in New Jersey in 

 1848. The figure was so striking, and the versifi- 

 cation so good, that I remembered them; although 

 I regret that the name of their author has escaped 

 me. He was a clergyman, and had a parish in 

 Pennsylvania. 



