128 Proceedings of the 



June 3d. Mr. Ritchie on the relation between Electricity a 

 netism, and on Electricity as the probable origin of all the phenomena 

 of Natural and Artificial Magnetism. After a few general observa- 

 tions on the nature and laws of action of voltaic electricity, Mr. Ritchie 

 proceeded to illustrate the striking relations between a conductor of 

 voltaic electricity and artificial magnets. As the law according to 

 which the needle, places itself across a conductor is easily forgotten, 

 the lecturer recommended the following artificial mode of viewing 

 it, as the best for fixing it securely in the memory. Regarding the 

 sun as the visible cause of terrestrial magnetism, and conceiving a 

 current moving round the earth in the direction of the sun's appa- 

 rent motion, from east to west, let a person conceive himself looking 

 towards the east, and then lying down on his back, with his feet to 

 the east, he may consider himself as a portion of a conductor, the 

 current of positive electricity entering at his feet and passing out at 

 his head. If he now conceive a magnetic needle suspended above 

 his chest, the north pole of this needle will arrange itself towards 

 his left hand, which will always be its direction, whether he thinks 

 of terrestrial or artificial electricity. 



Mr. Ritchie then described the mutual action of two voltaic con- 

 ductors, discovered by M. Ampere. If a voltaic conductor act on a 

 magnetic needle, it may follow that two conductors will act on each 

 other, and the manner in which they will act may be imagined by 

 reasoning a priori. If an indefinite number of very short magnets 

 be placed transversely on a flat piece of wood, with their poles of 

 the same name, all placed in the same direction, we shall have, says 

 Mr. Ritchie, something very like the section of a conducting wire. 



s 



Let AB be a slip of wood, having a great number of small magnets 

 made of portions of sewing needles, cemented on the slip of wood, 

 with all their south poles above and their north poles below, and let 

 a small magnetic needle be suspended above this compound bar, 

 and the needle will obviously arrange itself as in the annexed figure. 

 If two such bars be placed parallel to each other, as in the annexed 

 cut, with their poles in the same direction, and if one of them be 

 moveable, it will move parallel to itself, till it come in contact with 



i i i i I i I I I I I 



