( po ) 
by a Loop of fmall Cord faftened at the -End which 
was upwards ; I then carefully wiped the lower End 
of the Bar, and the Point of the Nail, that there 
might be no Dull, or Moifture, to prevent a good 
Contafl, taking Care not to touch either of them with 
my Finger, left Perfpirationfhould fully them. Then 
holding the Nail under the Bar very ered, with its 
Point upwards, I kept it clofe to the Bar, by only one 
Finger held under the Head of it, for the Space of 30 
or 40 Seconds or more. Then I withdrew iny Finger 
very gently, and directly downwards, that the Nail 
might not ofcillate ; and if it fell off, I wiped its 
Point as before, and tried it again at fome other Part 
of the Plain at the Bottom of the Bar ; for I always 
found it would more readily hang at one Place than 
another, and ufually the Middle was not fo well as 
towards one of the Edges or Corners, and the Succefs 
better nigh one Edge or Corner than another. If both 
Ends of the Bar are equal in Bignefs, and the Prepa- 
ration of their Ends fimilar, it is indifferent which End 
is downward, if it has no permanent Vertue : But if 
it has no more than an inchoate or imperfed Degree 
of fixed Polarity, one End will anfwer better, and 
the other worfe, in Proportion to the Degree of im- 
perfed Polarity which it has. 
XVIII. That of a foft Iron Bar void of fixed Po- 
larity, fo foon as it is in an ered Pofition, the higher 
Part from the Middle upward becomes a North Pole 
in North, or a South Pole in South magnetick Lati- 
tude. And, e contra^ the lower Part from the Middle 
downward becomes a South Pole in North, and a 
North Pole in South Latitude : But fo foon as ever 
the Bar is inverted, the Polarity will be fhifted in it, 
and 
