195 
1 88 1.] The Organisation of Matter . 
But as the mass expands the rigidity of conne&ion be- 
tween its particles decreases. Thus the resistance of its 
particles to heat impact decreases. It has partly lost the 
combined energy of imparl which it previously possessed, 
and needs greater individual momentum in its particles to 
enable them to resist an equal vigour of exterior impact. 
In other words, its capacity for heat increases as its temper- 
ature rises. 
In liquids a similar condition exists. They, too, have 
their normal pitch of heat vibration, which rises as exterior 
pressure increases. They have also their combined resist- 
ance to heat impact, which decreases as expansion increases, 
their capacity for heat thus augmenting. _ 
In gases these conditions are almost non-existent. The 
gas molecule is almost entirely free from coercion. Its field 
of movement may decrease or increase, but it continues to 
act almost entirely as an individual, and is little subject to 
the influences which liquid or solid molecules experience 
from their intimate relations of attraction with their fellows. 
The pitch of vibration of the gas particle is a resultant of 
its weight ; those of the liquid and solid particles of their 
combined weight and tension. 
If we consider the state of affairs existing in liquids we 
find a marked absence of rigidity. We may. imagine the 
liquid to be made up of minute spheres of rotating particles, 
the exterior portions of which are divided in allegiance be- 
tween two opposite centres of attraction. Such a freedom 
from special coherence of the exterior shells of such spheres 
must greatly reduce the frictional resistance between them, 
so that they may move upon each other with the greatest 
freedom. In the same manner the least disturbance of the 
liquid may cause a considerable transfer of allegiance in its 
particles, the material surrounding each centre of attraction 
being thus subject to frequent changes. Also any unoccupied 
space would speedily be filled by a new centre of attraction 
arising between the particles pressing into it. This consti- 
tution of a liquid mass is not apparent to us, from the 
minuteness of these spheres. But we perceive it in every 
instance where a water drop has an opportunity to assume 
its natural shape, it forming a globular mass around a centre 
of attraction, about which its particles are, very probably, 
in rapid rotation. Wherever a liquid has a fair opportunity 
to escape from certain opposing influences, and to display 
its normal tendencies, the globular shape immediately ap- 
pears. Ordinarily the liquid has to contend with gravity 
and atmospheric pressure, and frequently with cohesive 
