VOL. XXIV.] PHILOSOPHICAL TRANSACTIONS. 26l 



changed ; so that what was the north, becomes the south pole of the wire in all 

 respects ; I mean not only turning, but also embracing, or avoiding the poles of 

 the loadstone, as if it had received a new and contrary touch. Sometimes one 

 half of the wire will retain its magnetism, which it had before splitting, and the 

 other half have it quite changed. Sometimes no change at all will ensue, only 

 the magnetism be much weakened ; as indeed it always is in all the experiments 

 where the wire is split. But generally, where one of the halves has suffered 

 change, and the other not, I have observed, that it is the thinner and weaker 

 that has been changed, and the thicker has retained its virtue. Sometimes, 

 where one of the split halves receives an inverted verticity, or seems to have no 

 verticity at all, one of its ends will incline to one of the poles of the magnet, 

 not according to its touch, but in an inverted order, and the other end be at- 

 tracted indifferently by both the poles of the loadstone. And in some cases, 

 that end shall be attracted by one pole, but be neither attracted nor repelled by 

 the other; but stand as it were hesitating whether it had best fly to, or from 

 that pole of the loadstone. Only, if that pole of the magnet be too near, then 

 that end of the wire will constantly fiy to it : as indeed it is the nature of all 

 magnets and magnetic bodies to do, when they touch, or approach very near 

 each other, though they repelled before. 



The cause of these great changes in touched wire, produced by splitting, I 

 have sometimes imagined to arise from the violence exerted on it by bending. 

 But in some wires that I split, or cleft with very little bending, one half has 

 been utterly changed, but the other not. In others that I cleft, by suffering 

 the halves to bend as much as they would, no change has taken place ; and 

 some have suffered a total change. Sometimes I have imagined that the 

 splitting the wires in a north or south position, or that the beginning to split at 

 the north or south end of the wire first, might be the cause of this contraversion 

 of the poles: but trials showed there was little in any of this. 



There is one thing more that is very surprising, in split wire, viz. that the 

 laying the one or the other side of the half uppermost, will cause a great altera- 

 tion in its tendency, or aversion to the poles of the magnet. But if you lay 

 the contrary side of that half uppermost, the same end shall be attracted by 

 one, and repelled by the other pole of the magnet. In other pieces, where the 

 ends are regularly attracted or repelled, only in an inverted order, as if new 

 touched, if it lay with the round side uppermost at that time, and be then 

 turned upside down, viz. the flat cleft side uppermost, it is ten to one if one of 

 the ends be not either attracted by both the poles, or repelled by both ; or else 

 attracted or repelled by one, and hesitate as to the other : for so it often 

 happens. 



