( ) 
fame Pole of a large one, he foon changed the Polarity 
of the former, but could not effed it on a Piece of any 
confiderable Bignef?, though he tried fome Hours. I 
have changed-the Polarity of a fmall Fruflum of Load- 
ftone fuddenly, and without a Contad, by holding one 
of its Poles nigh the fame Pole of a Piece of Touched 
Steel much lefs than a common Cafe-Knife, at above « 
of an Inch diftant, which would make the Fruflum 
leap to it. I repeated thefe Changes frequently with 
the fame Fruflum. 
From this, and fome of the preceding Experiments, 
I conclude, that if two parallelopiped Loadftones equal 
in Magnitude and fimilar in Subfiance, Figure and 
Vertue, are placed clofe together as in Ffg. the 
with the North Pole of the one direded againfl the 
fame Pole of the other, or with the South Pole of the 
one againfl the South Pole of the other, and the Di- 
redion of their Polarities magnetically Eafl and Wefl, 
they will by RepuKion (as it were in a Duel) recipro- 
cally deflroy one another in an equal, though long 
Time : But if they are placed (in the fame Situation in 
refped of one another, w-s. North Pole againfl North 
Pole, or South Pole againfl South Pole) with the Di- 
redion of their Polarities in or near to the magnetical 
Line, that Stone (in North Latitude) whofe South 
Pole Hands direded to, or pretty much towards the 
attradive Point of the Earth’s central Magnet receiving 
Afhflance therefrom, will hot lofe Vertue fo fafl as 
the other, and confequently never lofe all its Vertue 
till it has perfedly deftroyed the Polarity of its An- 
tagonifl, which it will do in lefs Time, and afterward 
give it fome Polarity again contrary to what it had at 
firfl. 
XXIV. That 
U u a 
