MAGNETIC EXPERIMENTS. 57 
number of them could be united into one magnet, 
by means of a spare set of pins screwed throughout 
their length, and furnished with nuts. In addi¬ 
tion to these bars, &c. I provided separate feeders 
or conductors of soft iron, suitable for connecting 
the poles of each of the bars of the compound 
magnet, and also another conductor, fitted to the 
whole when combined. With this apparatus, I 
proceeded to give the magnetic virtue as follows. 
I took a rod of soft steel, which I considered 
better than a poker, and hammered it for a mi¬ 
nute or two, while held vertically upon a large 
bar of soft iron in the same position. This gave 
considerable magnetism to the steel-rod. On the 
top of this, I then hammered each of the six bars 
of soft steel, until the accession of lifting power 
ceased. Then fixing two of them on a board, 
with their different poles opposite, and formed, 
by a feeder at each end, into a parallelogram, I 
rubbed these, after the manner of Canton *, by 
means of the other four bars, and found their 
magnetism greatly augmented. The other four 
bars were operated upon in pairs, in a similar 
way, those already strengthened being used for 
strengthening the others, and each pair being suc¬ 
cessively changed, until all the bars were found 
* See Phil. Trans., vol. xlvii. p. 31. 
