t 3* ] 
double bar in thicknefs, the north pole of one, even, 
with the fouth pole of the other ; and the remain- 
ing two being put to thefe, one on each fide, fo 
as to have two north and two fouth poles toge- 
ther, feparate the north from the fouth poles at 
one end by a large pin, and place them perpen- 
dicularly with that end downward, on the mid- 
dle of one of the parallel bars, the two north poles 
towards its fouth, and the two fouth poles towards 
its north end : Hide them backward and forward 
three or four times the whole length of the bar, 
and removing them from the middle of this, place 
them on the middle of the other bar as before 
t 
dire&ed, and go over that in the fame manner; 
then turn both the bars the other fide upward, and 
repeat the former operation : this being done, take 
the two from between the pieces of iron, and 
placing the two outermoft of the touching bars in 
their room, let the other two be the outermoft 
of the four to touch thefe with : and this pro- 
cefs being repeated till each pair of bars have been 
touched three or four times over, which will give 
them a confiderable magnetic power, put the half 
dozen together after the manner of the four (Fig. 
3.) and touch with them two pair of the hard bars, 
placed between their irons at the diftance of about 
half an inch from each other : then lay the foft 
bars afide ; and with the four hard ones let the other 
two be impregnated (Fig. 4.) holding the touching 
bars apart at the lower end near two tenths of an 
inch, to which diftance let them be feparated after 
they are fet on the parallel bar, and brought toge- 
ther again before they are taken off : this being 
obferved, 
