An experiment which well illustrates the inductive power of the earth's
magnetism, may be made by placing a poker in one of these lines of
force, whose direction can be found at any part of the earth's surface
by means of proper instruments. When the poker is so placed, it will be
seen that it has actually become magnetized by the magnetism of the
earth, and it is itself able to attract iron filings or small needles.
These lines of force of the earth are closer together nearest to the
earth's surface than further away in space, and congregate around the
North and South magnetic poles, where they are greatest in number in a
given area, and there the magnetic intensity is the greatest.

Faraday, writing on the terrestrial lines of force, says: "The lines of
force issue from the earth in the northern and southern parts with
different but corresponding degrees of inclination, and incline to, and
coalesce with each other over the equatorial parts. There seems reason
to believe that the lines of magnetic force which proceed from the earth
return to it, but in their circuitous course they may extend through
space to a distance of many diameters of the earth, to tens of thousands
of miles."[37]

From this extract it will be seen that Faraday was of the opinion that
the lines of force extended beyond the atmosphere of the earth into the
Aether, which statement is confirmed by other parts of his writings;
though he was not able to give any physical explanation of how these
lines extended beyond the atmosphere on account of the doubtful
constitution and character of the Aether, although in another part of
his work he definitively refers to the magnetic character of space.

In writing on the magnetic character of space he says:[38] "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 static electric forces do (1616), and
therefore space has a magnetic character of its own, and one that we shall
probably find hereafter to be of the utmost importance in natural
phenomena." With the view of the Aether presented in this work, viz. that
Aether is matter, though in an infinitely more rarefied and elastic form,
we can now see the physical cause of the lines of force with which by his
imagination he filled all space.

Again, from the conception of the Aether presented to the reader in Art.
45, we learn