LECTURE III. 



EXPERIMENTAL PHILOSOPHY. 



MAGNETISM. 



IN my last lecture I endeavoured to make you 

 acquainted with the nature of attraction in ge- 

 neral. There is, however, scarcely any instance 

 in which the principle of attraction is displayed 

 in a more striking manner than in that of the 

 MAGNET, or LOADSTONE; so called, as Mr. 

 Adams conjectures, from load, the Saxon word 

 for lead, that is, the leading-stone, from its 

 proving a guide to seamen by means of the com- 

 pass, or magnetic needle, which always points 

 towards the north. 



The loadstone, or natural magnet, is an ore of 

 iron, found more or less in every iron mine. 

 Loadstones are of a dull brownish black colour, 

 and most of them are sufficiently hard to afford 

 sparks like a flint when struck with steel. They 

 differ very much both in form and in weight. 

 There was a very large one in the Leverian Mu- 

 seum, but it did not appear to be very powerful. 

 I observed in my second lecture, that the earth 

 itself has been compared to a large loadstone ; 

 and this opinion is countenanced by the immense 

 quantity of iron which is contained within its 

 bowels, or which indeed, more properly speaking, 



