1881.J The Organisation of Matter . 191 
reduce to some extent the number of centrifugal impacts. 
In another form of matter, the solid, they constitute the 
regular condition of temperature energy. In this form the 
attractive energy has become so greatly enhanced through 
contiguity of particles, and the impaCt energy so greatly 
reduced, that vibration has become the normal mode of 
temperature motion, and impaCt has become abnormal, in- 
stead of normal as in gases. There is no tendency here to 
the curvilinear mode of motion. The aggregation in solids 
has become so regular that attractive vigour aCts equally 
from all sides, its natural result, therefore, being the vibra- 
tion. If a gas could retain a homogeneous state of con- 
densation while continuing to lose temperature energy, it 
might at once pass into the solid state without entering the 
intermediate liquid condition. It would simply need that 
the attractive energy should become stronger than the tem- 
perature energy for the motion in straight lines to become 
vibrating motion, and thus for the solid state to be assumed. 
But gases are ordinarily heterogeneous in aggregation. 
Attraction aCts more vigorously from one side than from the 
other. Curved motions result. The closed curve finally 
arises, and the liquid form is produced. From this the solid 
is more easily constituted. The motions in liquids are far 
more regular than in gases. A much greater homogeneity 
of aggregation exists. The curve, affeCted by equal forces 
from both directions, tends to become the vibration, and the 
solid thus readily arises from the liquid. 
The gas, therefore, may be reduced to the liquid or the 
solid state by attraction overcoming momentum in two 
diverse modes. Attraction in a regular mass of particles 
tends to produce vibration ; in an irregular mass it tends to 
produce rotation. Yet it does not follow that these two 
results arrive at the same degree of reduction of tempera- 
ture. The vibrating particles constantly increase their dis- 
tance from the attracting centre, the vigour of this attraction 
thus rapidly decreasing. They also enter new fields of 
attraction which strengthen their motive vigour. Thus the 
lateral attractions which converge upon the centre of motion 
of the particle must be powerful enough to bring it to rest 
ere it can feel the full vigour of a new attractive field. In 
curved motion, on the contrary, the particle is held at a 
regular distance from the centre of attraction. This force 
does not diminish through increasing distance, nor is it 
overcome, to the same extent, by the influence of more dis- 
tant centres. Thus a less degree of energy is necessary to 
produce the closed curve than is required to yield the 
