length: Sc, I fay here again, as before of Ignitions, 
that of round Bars of the fame Diameter there is required 
a certain length, under which a fixt Pole can't be pro- 
duced by hammering, but of any length more than that 
certain length, you may make it; and then if you take 
a B^r Ihorter than that length of which you can't make 
a fixt Pole, while you keep that Diameter ; if 5'ou take 
a RoJ of the fame length but lefs Diameter, you may 
by blows produce a fixt Pole : Or if you only teat that 
thicker Bar thinner, you may produce a fixt Pole, tho' 
the Rod is never (o Ihorr, f rovided you beat it thin 
enough. 
7. What is faid of Hammering, is to be underftood 
of Filing, Grinding, Drilling, Sawing: yea, a hard Rub- 
bing, yea, a (oft Rubbing, provided 'tis long, will pro- 
duce fixt Poles,' the more heavy the blows are, cateru 
pariliu^ the Magnctifm is more: I fay, aeterii paribm^ 
as when the blows be not fo heavy in either cafe as to 
flat, for flatting the Iron produces more Magnetifm , 
though other things don t vary. A few hard blows will 
produce as much Magnetifm as many, as to fenfe , as if 
you give never fo many blows; yet a foft blow, may 
produce but little Magnetifm. The utmoft Magnetifm 
that I could produce in ordinary Rods this way, did not 
exceed that which an ordinary Loadftone would have 
infufed. 
8. Beating many Rods Northward, whofe lengths I 
knew fufiicienr, I never failed of producing a fixt North 
Pole ^ but hammering the fame or like Rods Southward, 
I found that I could not produce a fixt South Pole, only 
a mutable Pole ; nay, hammering one full South, I pro- 
duced a fixed North Pole : Then I thought the reafon 
might be, that the hammered South end on the Anvil 
was a little lower than the end which I held in my hand. • 
Then I held the end higher, and South upward, and 
fo 
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