i88i.] 
The Organisation of Matter . 
199 
force them into closed circles of rotation, so that impact 
may act as one of the controlling agencies upon their direc- 
tion of motion. In the article mentioned the rarefying effect 
of such impadt was considered. A similar influence, in a 
minor degree, may affect atoms and molecules when they 
come into collision, or when they feel the influence of mutual 
repulsion, their motion through space becoming temporarily 
converted into internal vibrations of their component parti- 
cles, or a widening of their radius of internal motion. 
The liquid organisation being thus possibly a rotation 
about an axis of attradtion, the question arises — What is 
the exadt condition of the solid organisation ? We have 
argued that solids might arise diredtly from gases, if these 
latter were perfedtly homogeneous. Such a homogeneous 
condition may exist in liquids. Their particles having a 
fixed vigour of movement, the centripetal energy arising 
from this momentum may be equal at every centre of organ- 
isation, so that ail of the minute globes may be of one fixed 
size. In such a case the liquid would be homogeneous, and 
every particle between and equally distant from the centres 
of two such globes would necessarily vibrate in a straight 
line, as though it were attached to the middle of an elastic 
cord joining these centres. If then, through loss of heat, 
these centres closely approached, there might in this way 
be an insensible change from the liquid to the solid state. 
But in the solid another mode of adtion of attractive 
energy is at work. Despite the fact that the attractions of 
a mass of particles converge and act from a general centre, 
the individual attraction between contiguous particles per- 
sists. While aiding the general force, it continues to act as 
an individual force. In the formation of a globe of liquid 
matter it is not alone the circling motions of the molecules 
which yield the attraction. A more vigorous force comes 
from the interior motions of the molecules. These, being in 
accordant directions, converge, not to an axis, but to a centre 
of attraction, and are probably far more vigorous than those 
of the circles of rotating motion. These latter possess a 
degree of centrifugal force, while the attractions of the indi- 
vidual molecules are wholly centripetal. 
But there is a degree of opposition between the local and 
the general exercise of molecular attraction. Every mole- 
cule is attracted in opposite diredtions by those immediately 
surrounding it, and tends to vibrate between these opposite 
attractions. There is thus a struggle between the local and 
the general attractions. In response to the one, the mole- 
cule seeks to rotate ; in response to the other, to vibrate. 
