29] 
which, spreading with excessive velocity in every direction, 
produce, according to the theory of Huygens, the effect of 
light. 
81. It is by the properties of this universally diffused ether 
that not only light , but also heat , and probably electricity and 
magnetism, are supposed to exist. And the fact of there being 
such latent light may be shown by the following experiment. 
Take two pieces of smooth flint and rub them together in a 
dark room, and the latent light or caloric matter will be imme- 
diately produced and become visible. The existence of this 
caloric or primitive light may be detected in various other 
bodies by rubbing two hard sticks together, or bv hammering 
cold iron, which, in a short time, becomes red hot, or by the 
sudden compression of atmospheric air in a tube. 
82. The theory originated by La Place respecting the ci’eation 
of our solar system* which is taken for granted by Humboldt 
and others, is an additional proof of light existing independent 
of the sun. La Place conceived that “ in the beginning” the 
whole solar system consisted of a mass of vaporous matter, 
having a central nucleus, and the whole rotating on its axis in 
one uniform direction, from west to east. Such a mass would, 
in condensing by cold, leave in the place of its equator zones of 
vapour composed of substances which require an intense degree 
of cold to return to a liquid or solid state. These zones must 
have begun by circulating round the sun in the form of con- 
centric rings, the most volatile molecules of which must have 
formed the superior part, and the most condensed the inferior 
part. In consequence of this revolving motion our globe 
became flattened at the poles and bulging at the equatorial 
region, and, in consequence of the greatness of the centrifugal 
force at the equator, and the contemporaneous condensation 
and contraction of the nebulous mass, a free, revolving ring, 
like that of Saturn, detached itself at the equator. This ring 
not being of uniform density, and in consequence of contraction, 
broke in one or more places, and these fragments, in obedience 
to the law of gravitation, became planets, revolving from west 
to east round the parent mass, f 
83. Thus, according to the theory of La Place, not only the 
earth, but all the planets, existed before the sun was in its 
present condition, as giving light to the earth. And as these 
* Professor Challis, in his Creation in Plan and Progress, considers that 
the Sun, like the other heavenly bodies, was “ created in the beginning” but 
was prevented from illuminating the earth during the first three Yoms or 
periods, by a vast stratum of vapour (see pp. 19 et seq.). 
f La Place, Exposition du Syst'cmc du Monde. pp. 465 et seq. Sec “Pertlv” 
for remarks on La Place’s theory. 
