( ^^9 ) 
Inch, and length lo Inches, you cannot produce a fet 
Pole by Ignition ; but if this Wyre were longer, as fup- 
pofe 30 Inches long, or never Vo much longer, 'tis ca- 
pable of a fixt Pole by Ignition : Again, take a round 
Rod 30 Inches long, and one loch diameter, this Rod is 
not capable of a fixt Pole at that length, though the 
leller was capable at that length. And (b my Experi- 
ments give me reafoo to think that there is no Rod or 
Bar of Iron ever fo thick, but which if it had length 
enough, would be capable of a fixt Pole by bare Igni- 
tion, for of that I only fpeak in this Paragraph ; and 
there is no Rod ever fo fliort, but which if you make 
it fufitciently thin, is capable of a fixt Pole. So when 
in a Rod I could not obtain a fixt Pole at 2 1 Inches 
length in that thicknefs, I could by making the Rod 
thinner produce a fixt Pole even in the length of one 
Inch and left, and the Pole fliould be of which kind I 
pleafid. ThQ terminus, or neceffary length for every 
thicknefs increafes more than you would be apt to 
think. 
J. Heat a Rod or its end red-hot, and throughly cool 
this end downwards, or towards the Nad/r, it will have 
fomewhat more Magnetifm than if cool'd Horizontally 
towards the North, But the better way is to cool it a 
little inclining towards the North. I cannot find that 
Multiplicity of Ignitions does produce more Magnetifm 
than one good Ignition ; but it muft be throughly ig- 
nited. Nor can I find by many Experiments that quench- 
ing in Water fignifies to the producing or hindering 
Magnetifm, but many Ignitions may accidentally pro- 
mote it by purifying the Iron. 
6. Dr. Power fays, That if we hold a Rod North- 
ward, and hammer in that pofition the North end, 
that will become a North Pole, i. e. a fixt North Pole ; 
contrarily if you hammer the Southend. Now this is true 
only in fome cafes, /c, k holds in Rods only of a certain 
length : 
