( ?07 ) 
Steel hammered hard, than the fame while foft ^ but 
Steel hardened by quenching, than either of them. 
My Obfervation has been, that Steel cannot be feafon- 
ed too hard for Retenfibn (nor, as I think, for Recep- 
tion) of Magnetifm ; but may fometimes warp too 
crooked for its intended Ufe, and muft be made right 
again fome Way or other, either with a Grinding- 
Stone, or (if that will not do) by heating it to a blue 
Colour, and gently hammering it while hot ; but if 
it can be helped, the Temper for the blue Colour is 
too foft. 
XL It has been obferved ,.that oblong Pieces of Iron 
or Steel applied any how to the Loadftone, receive 
Vertue chiefly (fome fay only) as to their Lengths. 
This was what induced me to explain Fig. jthy 
in the Middle of Pag. 304. For I think it a 
parallel Cafe with this here, and fuppofe that the 
Vertue may incline to run length-ways even in the 
Loadftone itfelL However, I think if it muft be al- 
lowed to be length-ways, it is fometimes found to be 
very irregular in pretty long Pieces, as North Pole 
againft North Pole, South Pole againft South Pole fe- 
veral Times in the fame Piece, which feveral contrary 
Polarities have been obferved by feveral in Wires, and* 
Ihavefeen in a round Bar (of which Irregularity, and 
the Method of curing if, more hereafter) But fuch 
contrary Polarities feera unaccountable^ 
XII. That fuch Iron and Steel as has magnetick 
Vertue communicated to it, does alfo communicate 
thereof to other Iron or Steel after the fame Manner 
a Loadftone does. Which Vertue, after never fo many 
Communications, is, as to its Nature, perfectly the 
fame with that of the Stone itfelf, having both Poles, 
1 . and 
