OF FERRUGINOUS BODIES. 241 
proving, that magnetism, properly applied, may 
be made a powerful auxiliary in giving strength 
to iron bars.* 
75. Although it has long been known that 
agitation facilitates the polarization of ferruginous 
bodies when under the influence of a standard 
magnetic force, such as that of the earth, I am 
not aware that any experimental inquiries have 
hitherto been made with a view to ascertain the 
extent of polarization that different kinds of iron 
and steel are susceptible of receiving by that simple 
process. But, in order to ascertain how far the 
views I have taken, respecting the polarization 
of ferruginous bodies, whilst cooling from high 
temperatures, accord with facts, I took an oppor- 
tunity of making a few trials on those bars, both 
solid and hollow, which had been employed in the 
experiments already detailed. 
* It being well known that electric currents are capable of 
keeping together two distinct masses of iron, with a force 
equal to many tons; why, I would ask, should not the same 
power keep together the particles of a single piece of iron, 
with an equal force, in addition to the force of cohesion. 
Some experiments which I have made, seem to sanction this 
view. 
