240 PECULIARITIES IN THE MAGNETISM 
display of magnetic powers is due to the direct 
influence of the calorific matter. I would rather 
refer it to the molecular movements of the metallic 
integrants of the bar, whilst contracting, and at 
atime when the magnetic matter is in the best 
possible condition for receiving polarization, viz. 
whilst re-entering the bar, and consequently ina 
state of motion. 
73. That agitation of a ferruginous mass, and 
consequently of its contained magnetic particles, 
facilitates its polarization, is a fact long ago esta- 
blished: and to such a degree of importance has 
this simple fact arisen, that philosophers are now 
accusing it. of being the chief agent in producing 
disruption of the iron axles of railway carriages, 
whilst travelling at a great speed. 
74. I, however, do not blame any magnetic 
action as being either directly or indirectly con- 
cerned in these unfortunate occurrences : nor can 
I learn that any experimental results have hitherto 
been obtained, that could give rise to the idea 
that there is even a possibility of magnetism 
weakening the cohesive powers of iron: but on 
the contrary, from some inquiries that I have 
made on this topic, I am not without hopes éf 
