44 Dipping of tbe Needle. (Book I. 



though it originally -might belong to a part of the 

 magnet which was altogether of a certain polarity *. 



III. Magnets, while they attract other bodies, ap- 

 pear themfelves to be fubject to the attraction of the 

 earth ; for a magnet, or magnetic needle, when placed 

 fo as to be able to* act according to its native impulfe, 

 inclines one of iis poles a little to the earth, while the 

 other is proportionably elevated : this is called the 

 dipping of the needle, and the inclination or dipping is 

 found to be different in different latitudes. Near the 

 equator the needle affumes a pofition almoft perfectly 

 horizontal ; in the northern hemifphere the fouth pole 

 is depreffed or attracted to the earth ; and in the 

 fouthern latitudes the north pole of the magnet fuffen 

 a fimilar depreflion, 



This property of the magnet is accounted For upon 

 die fame principle as the former, namely, by fuppof- 

 ing that the earth, from the quantity of ferrugmeous 

 matter which it contains, acts as an immenfe load- 

 ftone, which at its poles attracts thofe of every other 

 magnet fufpended above its furface. It has more 

 than once been repeated, that magnets attract each 

 other at the oppofite poles. Thus, if a fmall magnet, 

 or magnetic needle, is fufpended by a thread above a, 

 larger magnet, while its poles are at equal diftances 

 from the poles of che larger magnet, it will remain in a 

 horizontal pofition ; but if it is removed either one 

 way or the other, that is, if one pole of the fmaller 

 magnet is moved towards the contrary pole of the 

 larger, it will be attracted towards the perpendicular. 

 This is exactly illustrative of the dipping needle, which 

 upon the equator remains in an equilibrium, but 

 inclines to the perpendicular as it approaches to 



Cav. 218. 



the 



