202 
HINTON. 
This geometric image corresponds to the definition of an 
electric circuit. It is known that the action does not lie in 
the wire, but in the medium, and it is known that there is 
no direction of flow in the wire. 
No explanation has been offered in three-dimensional me¬ 
chanics of how an action can be impressed throughout a 
region and yet necessarily run itself out along a closed 
boundary, as is the case in an electric current. But this 
phenomenon corresponds exactly to the definition of a four¬ 
dimensional vortex. 
If we take a very long magnet, so long that one of its 
poles is practically isolated, and put this pole in the vicinity 
of an electric circuit, we find that it moves. 
Now, assuming for the sake of simplicity that the wire 
which determines the current is in the form of a circle, 
if we take a number of small magnets and place them all 
pointing in the same direction normal to the plane of the 
circle, so that they fill it and the wire binds them round, 
we find that this sheet of magnets has the same effect on the 
magnetic pole that the current has. The sheet of magnets 
may be curved, but the edge of it must coincide with the wire. 
The collection of magnets is then equivalent to the vortex 
sheet and an elementary magnet to a part of it. Thus, we 
must think of a magnet as conditioning a rotation in the 
ether round the plane which bisects at right angles the line 
joining its poles. 
If a current is started in a circuit, we must imagine vor¬ 
tices like bowls turning themselves inside out, starting from 
the contour. In reaching a parallel circuit, if the vortex 
sheet were interrupted and joined momentarily to the 
second circuit by a free rim, the axis plane would lie be¬ 
tween the two circuits, and a point on the second circuit 
opposite a point on the first would correspond to a point 
opposite to it on the first; hence we should expect a‘current 
in the opposite direction in the second circuit. Thus the 
phenomena of induction are not inconsistent with the hy¬ 
pothesis of a vortex about an axial plane. 
