1882.] The Principles of Magnetism. 69 
continue, except in the neutral equatorial plane which sepa- 
rates the two vortices. 
These ideas, differing widely as they do from those usually 
entertained in regard to terrestrial magnetism, in reality need 
but one admission for their establishment. Admit that the 
magnetic needle is really part of the earth, and its magnetism 
part of the earth's magnetism, and all the conclusions here 
reached seem to necessarily follow. Its changes in axial 
position indicate like changes taking place in the earth’s 
magnetism, and could only occur under the astatic influence, 
as here considered. And, as the single energy of gravitation 
yields a single centre of attraction, so the dual energy of 
magnetism must yield two centres of attraction, which all 
may judge, both from the behaviour of the magnet and from 
the necessary results of astatic action, to occupy the posi- 
tions above deduced. 
The views of magnetic distribution, as here applied to the 
earth, must equally apply to all minor magnetic masses. 
And there is much reason to believe that they do so apply. 
If we take a large magnet, and place near it a minute 
testing needle, we discover phenomena similar to those dis- 
played by the earth. At the equator the testing steel sets 
itself parallel to the magnet. Moving towards either pole 
it displays the magnetic dip, and, at a certain point between 
the equator and the pole, it stands perpendicular to the axis. 
Carried still forward the dip increases, until, at the imme- 
diate pole, a half revolution has taken place, and the needle 
has become direCtly parallel to the axis of the large magnet, 
instead of reversely parallel, as when at the equator. These 
phenomena are not so distinctly declared in ordinary mag- 
nets as in the earth, on account of their difference in shape. 
Magnets are usually elongated, slender masses, and the 
point where the testing needle stands vertical is nearer the 
pole the more long and slender they become. When thick 
and short this point moves towards the equator, until it often 
assumes a position at one-third of the distance from the pole 
to the equator. Probably, if the magnet were spherical in- 
stead of cylindrical, this vertical point would assume a 
position similar to that it has in the earth — nearly midway 
between pole and equator. 
It is not necessary that the testing needle be magnetised. 
Induced magnetism will cause it to go through the same 
series of evolutions. But does not this lead us to a new 
conception of the state of affairs existing within a magnet ? 
Magnetism, as we have already considered, does not belong 
to the mass as a whole, but to its molecules as individuals. 
