ated world with but a single quality--a
force of attraction. It not only had attraction for its own material
substance, but sent out an all-pervasive attraction into space. By
the force of condensation it flamed like a sun, and not only lighted
its own substance, but it filled all space with the luminous outgoings
of its power. A world may be limited, but its influence cannot;
its body may have bounds, but its soul is infinite. Everywhere is
its manifestation as real, power as effective, presence as actual,
as at the central point. He that studies ponderable bodies alone
is not studying the universe, only its skeleton. Skeletons are
somewhat interesting in themselves, but far more so when covered
with flesh, flushed with beauty, and inspired with soul. The
universe [Page 18] has bones, flesh, beauty, soul, and all is one.
It can be understood only by a study of all its parts, and by
tracing effect to cause.

But how can condensation cause light? Power cannot be quiet. The
mighty locomotive trembles with its own energy. A smitten piece
of iron has all its infinitesimal atoms set in vehement commotion;
they surge back and forth among themselves, like the waves of a
storm-blown lake. Heat is a mode of motion. A heated body commences
a vigorous vibration among its particles, and communicates these
vibrations to the surrounding air and ether. When these vibrations
reach 396,000,000,000,000 per second, the human eye, fitted to be
affected by that number, discerns the emitted undulations, and the
object seems to glow with a dull red light; becoming hotter, the
vibrations increase in rapidity. When they reach 765,000,000,000,000
per second the color becomes violet, and the eye can observe them no
farther. Between these numbers are those of different rapidities,
which affect the eye--as orange, yellow, green, blue, indigo, in an
almost infinite number of shades--according to the sensitiveness
of the eye.

We now see how our dark immensity of attractive atoms can become
luminous. A force of compression results in vibrations within,
communicated to the ether, discerned by the eye. Illustrations are
numerous. If we suddenly push a piston into a cylinder of brass,
the force produces heat enough to set fire to an inflammable substance
within. Strike a half-inch cube of iron a moderate blow and it becomes
warm; a sufficient blow, and its vibrations become quick enough to
be seen--it is red-hot. Attach a thermometer to an extended [