Electro-Magnetic Engine. 



343 



Art. XIV. — Electro- Magnetic Engine, constructed by the late 

 A. W. Campbell, of New Orleans, — communicated by Prof. 



RiDDELL. 



This engine, now in my possession, was the result of two or 

 three years of study and numerous experimental trials. Mr. 

 Campbell was a teacher by profession. His opportunities for ac- 

 quiring a knowledge of natural science were very limited, but 

 his zeal and singleness of purpose are seldom exceeded. He 

 died in January, 1838, leaving his design not quite finished. 



His engine differs in some respects from those constructed by 

 others. It consists essentially of two large and solid electro- 

 magnets, of soft iron, in the form of the letter U, coated with 

 coils of copper strips one inch broad by half a line in thickness. 

 These copper coils are insulated by being wound with strips of 

 paper. The electro-magnets weigh, each, about one hundred 

 pounds, and are arranged horizontally, the opposing poles being 

 about eight inches apart. Between them plays the keeper of soft 



iron, K, after the manner of a piston of a steam engine. When 

 the magnet, R, is connected with an active pair of galvanic plates, 

 K is attracted by its poles. A reversed current of the galvanic 

 fluid from a smaller pair of plates, is then sent around the mag- 

 net, sufficient in quantity to destroy its magnetism the moment 

 after the connection with the large galvanic pair is broken. At 

 this instant the magnet L is made to attract the keeper ; the con- 

 nection is then broken, and the current reversed as before ; and 

 thus a returning horizontal motion is given to the keeper and its 

 appurtenances. The connections are broken and reversed by the 

 dipping of amalgamated slips of copper into mercury. 



New Orleans, November, 1838. 



