OF FERRUGINOUS BODIES. 245 
the slake trough. The bar, thus treated, was 
then placed in the line of the dip, as in former 
experiments, with its heated end uppermost, hay- 
ing the compass needle at the distance of six 
inches on the eastern side. 
The hot end showed no magnetic action what- 
ever. I now requested the smith who assisted 
me, to raise the bar till nearly the whole of the 
heated part was above the compass. In this 
position the north end of the needle was drawn 
towards the bar about 25°, indicating the presence 
of a pole of the opposite kind. 
The character and situation of this pole being 
ascertained, the bar was again gradually raised, 
tillits lower extremity was level with the compass. 
The deflection of the needle at first declined, and 
gradually returned to the meridian, as the centre, 
or nearly the centre, of the cold part was raised 
to its own level. As the bar ascended higher, 
the declination of the needle was again shown, 
but in the contrary direction to the former ; and 
when the lower end of the bar had reached the 
level of the needle, the south end of the latter 
was drawn towards it about 27° 
ri 
