so easy as might at first sight be imagined. For the action of the
magnet upon any gas, while surrounded by air or any other gas, can
only be differential; and if the experiment were made in vacuo, the
action of the envelope, in this case necessarily of a certain
thickness, would trouble the result. While dealing with this
subject, Faraday makes some noteworthy observations regarding space.
In reference to the Torricellian vacuum, he says, 'Perhaps it is
hardly necessary for me to state that I find both iron and bismuth
in such vacua perfectly obedient to the magnet. From such
experiments, and also from general observations and knowledge, it
seems manifest that the lines of magnetic force can traverse pure
space, just as gravitating force does, and as statical electrical
forces do, and therefore space has a magnetic relation of its own,
and one that we shall probably find hereafter to be of the utmost
importance in natural phenomena. But this character of space is not
of the same kind as that which, in relation to matter, we endeavour
to express by the terms magnetic and diamagnetic. To confuse these
together would be to confound space with matter, and to trouble all
the conceptions by which we endeavour to understand and work out a
progressively clearer view of the mode of action, and the laws of
natural forces. It would be as if in gravitation or electric forces,
one were to confound the particles acting on each other with the
space across which they are acting, and would, I think, shut the
door to advancement. Mere space cannot act as matter acts, even
though the utmost latitude be allowed to the hypothesis of an ether;
and admitting that hypothesis, it would be a large additional
assumption to suppose that the lines of magnetic force are
vibrations carried on by it, whilst as yet we have no proof that
time is required for their propagation, or in what respect they may,
in general character, assimilate to or differ from their respective