1 882.3 The Principles of Magnetism. 71 
exterior molecules of the magnet, and reveal the conditions 
existing in its interior. Over the equator they extend in 
lines parallel to the axis. Farther north or south they dip, 
and eventually become vertical to the axis. This dip in- 
creases, until at the poles they stand reversely parallel to 
their former direction, and in the line of the axis. Through- 
out the axis this reverse parallelism doubtless continues. 
If the magnet be touched to the iron filings these attach 
themselves strongly to the poles, and weaken in their attach- 
ment as they approach the equator, where they fail to attach 
themselves. From this it is argued that magnetism is 
strongest at the poles and weakest at the equator ; but such 
a conclusion does not necessarily follow. At the equator the 
axes of the molecules are directed parallelly to the axis of 
the magnet. Thus their energy is not exerted outwardly. 
And as the magnetism of the surface molecules is similar in 
direction to that induced in the filings, they must repel in- 
stead of attracting these. Leaving the equator the dip 
begins. One pole of the molecule is directed outwardly, 
and an attractive influence is exerted. This increases stea- 
dily towards the poles, at which one pole of the molecule is 
turned direCtly outwards. The faCt that the molecules and 
filings are similar in axial direction, which would cause re- 
pulsion were they side by side, causes attraction when they 
are end to end. 
We have argued, from the admitted premises, that the 
magnetism of masses is a combined result of the magnetisms 
of their constituent molecules. We may now ask, What is 
the magnetism of a molecule ? And in this question a 
second is involved — What is a molecule ? To give the latter 
its general expression we say — A molecule is an aggregation 
of atoms. And we shall probably have to seek in these 
atoms the true origin of the phenomena of magnetism, and 
the cause of its many variations in strength and character. 
According to the theories of Ampere and Weber magnetism 
arises from the flow of constant eleCtric currents around the 
surface of molecules. The Amperian theory is constantly 
and gravely repeated in text-books, to the present day, with- 
out a hint being given of the indisputable faCt that it is quite 
at variance with the principles of energy, as now understood. 
It is easy to imagine a constant current of electricity, and 
make it answer a definite purpose, but the truth is that no 
such thing exists as a constant current of electricity, in the 
Amperian sense. 
The current of static electricity is instantaneous. It 
ceases as soon as the eleCtric equilibrium has been restored* 
