248 Mr. Scoresby Junior’s experiments and observations on the 
The general results of these experiments are as follow : 
1. A cylindrical bar of soft steel , 6~ inches long, and 
weighing 592 grains, lifted, after repeated hammering on 
pewter and stone, 6? grains ; but could not be made to lift a 
nail of 11 grains. 
2. The same bar hammered vertically upon a parlour 
poker, the poker also held erect, after 22 blows, lifted, with 
the lower end, which was a North pole, 88 grains (2 a) ; and 
on using a larger hammer, received a considerable increase 
of power, producing a deviation of the compass, three inches 
distant, of 34 degrees (2 b) : farther hammering, it was 
found, rather diminished than increased the effect (2 b). On 
the bar being inverted, so that the north pole was upward, 
the magnetism was very nearly destroyed by a single blow ; 
while two blows changed the poles (2 c). Hammering the 
end of the bar in the plane of the magnetic equator also de- 
stroyed the polarity ; but the effect was not fully produced 
until many blows had been struck. 
When the poker had been previously hammered in a ver- 
tical position, an increase of magnetic effect on the bar was 
obtained ; a single blow being now sufficient to enable the 
bar to lift about 20 grains : and when the end was ham- 
mered into a kind of cup, so as to be easily bruised, the bar 
was, by one blow, rendered capable of lifting between 30 
and 40 grains (2 e ). After 10 blows, the highest effect ob- 
tained in all the experiments was produced, the same bar 
readily lifting a nail of 188 grains, being nearly one-third 
of its own weight ! (2 e). 
The magnetism by percussion was found, by subsequent 
experiments, to be augmented when the length of the bars 
