i86 
The Organisation of Matter . 
[April 
must have moved through space in the common direction of 
motion of the general mass, but its remaining motive vigour 
may also have become partly accordant, yielding it indivi- 
dual mass motion of its own, in some special direction. The 
individual motions of the minutest elements of the nebula 
would thus, through partial loss of motion in certain direc- 
tions, become combined motions of minor aggregations of 
these elements in the opposite directions. But the direction 
of motion in these small masses would be subjedt to frequent 
changes through impaCt with other like masses. 
It may be well here to consider an essential distinction 
between the results of impaCt and directive energy. An 
axiomatic phrase will indicate this distinction. ImpaCt is 
centrifugal in its influence, attraction is centripetal. It may 
further be premised that impaCt is instantaneous, attraction 
and repulsion are gradual ; impaCt yields straight lines and 
fixed speed of motion, attraction and repulsion yield curved 
lines or varying speed ; impaCt aCts immediately and through 
contact, attraction and repulsion aCt persistently, and from 
a distance. 
Did impaCt exist alone all force would be centrifugal ; 
there could be no organisation, and heterogeneous matter 
would perhaps tend to become homogeneous. It certainly 
could not tend to greater heterogeneity. All organisation 
results from the aCtion of directive force, and the production 
of accordance between the motions of particles, under its 
influence. Attraction produces not a single initial change 
of direction and speed, — like impaCt, — but a continued series 
of such changes, and causes uniform motion in straight 
lines either to become motion in curved lines, or to accele- 
rate or diminish in speed, according to the direction from 
which the force aCts. This is the first specialisation of 
motion. It aCts to reduce the amount of centrifugal energy, 
by bringing motions into parallel relations, and thus reducing 
the frequency of impaCt. Similar effects are produced by 
repulsion, but they differ from those of attraction by being 
gradually diminishing instead of gradually increasing 
effects. 
The second specialisation of motion is produced when 
from the open curve proceeds the closed curve, motion in 
straight lines having thus changed into motion around a 
centre of attraction. In this condition of motion its centri- 
fugal energy vanishes ; all its force has become centripetal. 
And such a condition is essentially a persistent one. The 
centre of attraction around which the motions rotate owes 
its vigour to these motions, and thus must retain them in 
