6n 
1880.] The Vehicle of Force . 
with it must be the movement of a force pertaining to 
motion. For the outgoing motion could not conveniently 
sweep away inherent force from one substance to plant it in 
another ; nor could a force attribute of matter well go to 
sleep in one mass the instant motion left it, and awake in 
another the instant motion entered it. Similar shifting 
phenomena of force might be shown in other instances of 
the transfer, or the sudden aCtion, of motive energy, all 
tending to strengthen the position we have taken. But 
without specially considering them here we will try to deduce 
from the force manifestations of Nature the law which 
governs this directive principle of motion. 
Our work is, in faCt, largely done to our hand, by the in- 
vestigators of electrical phenomena. We know that if 
eleCtrical currents are sent through two contiguous wires, 
these wires exert a marked influence upon each other. If 
the currents proceed in the same direction, the wires are 
drawn together. If in opposite directions, they are mutually 
repelled. In this case substances, which previously had no 
apparent influence upon each other, are by the addition of 
motive energies exerted in similar directions, caused to 
approach, and to separate if the energies move in opposite 
directions. 
In the case of magnetism the same result appears, since 
magnetism is believed to be an effeCt arising from the 
circling of motive vigour around the particles of matter, 
magnetic attraction arising from parallelism in these mo- 
tions, and repulsion from reversal of their directions. The 
inter-aCtions of eleCtric and magnetic force yield the same 
result, masses of matter being moved in the effort to pro- 
duce parallelism of motion. The full expression of the 
principle involved is the following : Motive currents which 
move towards or from the same point in space, atttraCt , 
while those that move one towards and the other from a 
point, repel. 
May we not have here a ready solution of the whole diffi- 
culty of these forces? Matter cannot well change its 
character, but motion can very readily change its direction ; 
and the above principle may cover the whole question. We 
may, in faCt, formulate a law of directive force as follows 
All matter in motion exerts an influence over the direction 
of all other matter in motion, this influence proceeding from 
motion disappearing with the cessation of motion, and 
augmenting with its increase. Any two motions parallel, or 
tending towards or from the same point, are forced to ap- 
proach each other. Any two motions reversely parallel, or 
