Experiments and Obfervations . 1 1 
net will evidently attract what a weaker one will not move ih 
the lead. 
I fhall laHly obferve, with refpedt to the experiments of laH 
year’s lefture, that though then I thought to have fufed and 
incorporated together brafs and iron, yet fome fubfequent trials 
gave reafon to believe, that the iron is concealed in l'ome part 
or other of the melted brafs, rather than equably diffufed 
through the fubHance of the latter ; -and the principal reafon 
for this iufpicion is, that when thofe pieces of mixed metal 
are tried upon the quickfilver, fome points in their furfaces are 
generally attracted by the magnet in preference to others. 
Experiments and obfervations relating to the attraction between 
ferrugineous fubfances and the magnet , in their different Jtates 
of exigence ; to which are added , fome thoughts concerning the 
caufe of the variation of the needle. 
It is a proportion well eHabliflied in magnetics, that foft 
iron, or foft Heel, acquires magnetifm very ealily, and loles it 
with equal facility ; but that hard Heel acquires that power 
with difficulty, and afterwards retains it obflinately. From 
the confideration of thole properties I was led to imagine, that 
if a piece of Heel, whilft red-hot, were placed between magnetic 
bars, and whilft Handing in that lituation cold water were to be 
luddenly poured upon it, fo as to harden it, there might, per- 
haps, be obtained an artificial magnet, much more powerful 
than what can be produced by the ordinary way ; becaufe the 
magnetic bars, employed lor fuch purpoie* would communi- 
cate a great degree of magnetic power to the Heel, when red 
hot and confequently fott, which power would be fixed upon 
the Heel by the hardening. 
C 2 
111 
