OF FERRUGINOUS BODIES. 250 
when compared to those which we have at com- 
mand by the employment of artificial magnets, 
and electric currents ; and as it seemed possible 
that, although no polarity of highly heated iron 
could be detected from the polarizing influence 
of the earth, yet a much higher polarizing power 
might develop some trace of magnetic action in 
the iron, even at the highest degree of tempera- 
ture at which it could be kept in a solid state; 
and as no hypothesis ought to be ventured on the 
philosophical world, which rests on doubtful, or 
even partial, experimental data, it was easy to 
perceive the propriety of extending the experi- 
ments for the purpose of ascertaining what results 
could be derived from the employment of a much 
more powerful polarizing force than that of ter- 
restrial magnetism. 
92. In order to carry out these inquiries in 
the most satisfactory manner possible, I first 
ascertained the entire neutrality of a heated bar 
of square iron, six inches long, and 0°6 of an inch 
broad, when subjected to terrestrial magnetic 
action in the line of the dip, as in some of the 
experiments already detailed. 
93. As it was necessary to have some idea of 
