l88o.] The Origin of Falling Motion. 375 
consequence. The relations of position between particles 
or masses at a distance from each other are general, and 
their attradtion takes the generalised form of gravitation. 
The relations of position between particles in close conti- 
guity are special, and their attractions become specialised. 
The modes of motion resulting are in direct response to the 
mode of attraction, and are readily convertible into each 
other at every variation in attraction. 
As the generalised mode of attraction is gravitation, so 
the generalised mode of motion is the movement of the gas 
particle. This is so vigorous in its action as to resist the 
attracting energies of contiguous particles. Its motion is, 
therefore, influenced in vigour only through impact, and in 
direction only through impact and gravitative attraction. 
It is constantly falling in response to gravity, and constantly 
rebounding in response to impact. Wherever the resisting 
impacts are reduced in quantity the gas particles move in 
greater number, this movement constituting a wind, which 
increases in force as the resistance to the individual move- 
ments of the particles decreases in quantity. 
Give the particles an opportunity to strike together with 
special ease in one direction, and a wind necessarily ensues. 
A fall, in response to gravitation, only ensues when the par- 
ticles near the surface are separated by increased temper- 
ature, or through some other cause, so that their resistance 
to impadt is decreased. 
Attraction of gravitation, therefore, has no influence in 
increasing or decreasing the motive energy of matter. Its 
only influence is directive. It controls the direction of the 
motions of particles, so far as its control is not resisted by 
some other controlling attraction. The direction and mode 
of motion of the particle, at any instant, is a resultant of 
all the attractive and repulsive forces aCting upon it at that 
instant, gravitation being simply a constant component of 
these forces. 
The vigour of motion possessed by the particle can vary 
only in two ways. One of these is by impaCt, in which the 
energies of the two impacting particles may become changed, 
their sum remaining unchanged. The other is by the re- 
sistance of attraction. Here the particle loses motion, but 
gives its lost motion to the attracting particles, which it 
drags into swifter speed. 
Motion cannot die nor be born. It can only be transferred 
in amount and changed in direction. 
