[ 38 ] 
in lefs than two minutes : and therefore will anfwer 
all the purpofes of magnetifm in navigation and ex- 
perimental philofophy, much better than the load- 
ftone, which is well known not to have Sufficient 
power to impregnate hard bars. The half dozen 
being put into a cafe (Fig. 6.) in fuch a manner, 
as that two poles of the . fame denomination may 
not be together, and their irons with them as one bar, 
they will retain the virtue they have received: but 
if their power fhould, by making experiments, be 
ever fo far impaired, it may be reftored without any 
foreign affiftance in a few minutes. And if, out of 
curiofity, a much larger fet of bars fhould be re- 
quired, thefe will communicate to them a fufficient 
power to proceed with, and they may in a Short 
time, by the fame method, be brought to their full 
Strength. 
end of each a fmall wire to take them out by : he then quite fills 
tbe pan with the leather, aH places it on a gentle flat fire, cover- 
ing and furrounding it with charcoal. The pan being brought to 
fomewhat more than a red heat, he keeps it fo about half an hour, 
and then fuddenly quenches the bars in a large quantity of cold 
water. 
