132 Description of a Magneto-Electric Machine, Sfc. 



Independent of its utility to the farmer, it would be highly 

 useful to the mariner in the following way. 



As the very time and place of the commencement of the rain 

 would be known, it would be easy to find out in what direction 

 from the place of beginning it moved along the surface of the 

 earth, and also its velocity of motion, and the shape that it as- 

 sumed from time to time in its progress. Now this knowledge is 

 the principal thing wanting to enable the mariner, who has the 

 power of locomotion, to direct his vessel so, when one of these 

 great storms comes near him, as to use as much wind in the bor- 

 ders of the storm as will suit the purposes of navigation — for 

 heaven undoubted makes the wind blow for his use and not for 

 his destruction, provided he becomes acquainted with the laws to 

 which it is subject. From the preceding principles he will be 

 able to know in what direction a great storm is raging when it is 

 yet several hundred miles from him. 



Art. XVI. — A Description of a New Form of Magneto- Electric 

 Machine, and an Account of a Carbon Battery of conside- 

 rable energy ; communicated for this Journal by Oliver W. 

 GiBBs, member of the Junior Class of Columbia College, N. Y. 



It is well known, that if a soft iron bar be wound with insu- 

 lated wire and caused suddenly to approach and recede from the 

 poles of a magnet, temporary magnetism will be induced in the 

 bar, and an electric current in the wire surrounding it. This fact 

 led to the construction of the magneto-electric machine, the prin- 

 ciple of which consists in alternately inducing and destroying 

 magnetism in a bar similarly wound with large wire for sparks 

 and deflagrations, and with small for shocks and chemical decom- 

 positions. About eight months since it occurred to me that a 

 more simple machine than those commonly used (and which all 

 I believe resemble that of Saxton) might be constructed. My 

 plan was, to take a bar of soft iron of say an inch in diameter by 

 ten inches long, and to slide upon the middle a disk of brass of 

 two inches radius. This would divide the bar into two parts, 

 upon one of which is to be wound three or four hundred feet of 

 copper bell wire well insulated, and upon the other and separated 

 from the first by the brass disk, about four times that length of 

 fine wire, say No. 25. If now one extremity of the coarse wire 



