69 
Now what does this answer imply ? The ether is conceived 
to extend far beyond the system of which it is an essential 
part, and that with unabated elasticity. If there is no restraint 
at the boundary, it must have gone on expanding, from the 
date of the first nebula, through countless ages. However 
great the original elasticity, it must have become insensible in 
amount millions of years ago. The first word in a true record 
of man's creation, in this view, would not and could not be — 
Let there be light ! but rather. Let there be eternal stagnation 
and midnight darkness. 
To account for the high elasticity of the ether, after ages 
have passed, we must either assume a solid limit or boundary 
of the stellar universe, such as Milton describes, or else that 
the ether thins and is less elastic at the outside, like the 
highest sti’ata of the earth's atmosphere, till its repulsion is 
balanced by its affinity for the matter which adjoins it. In 
either case there could be no dissipation of energy. It would 
be restored, either by rebound from the solid wall of the system, 
or on the other view, by change into potential energy at the 
elastic boundary of the universe. 
But the energy, though its amount be unchanged, may per- 
haps become degraded and inferior in kind. Working energy 
may grow idle and worthless. As unequal temperature, it can 
do much work. As equalized temperature, its working power 
is gone. The great waste-heap goes on accumulating, as 
posterity may learn some day to their cost. The universe will 
then become “an equally-heated, inert mass, from which ail 
life, motion, and beauty have utterly gone away." 
Heat is atomic motion. Equal diffusion of heat cannot, then, 
be the same with absolute rest. If the heat of our solar system 
were shared equally among the sun, planets, and satellites, we 
should not be frozen to death with absolute cold. On the 
contrary, we should plainly be burned up with a fiery confla- 
gration. The temperature of our globe would become much 
higher than the heat of melted iron. 
In the view of science energy is only of two kinds. The 
nebular theory implies that it was once mainly potential, or the 
energy of distance, and that motion, the other kind of energy, 
has replaced the first, as the nebula condensed. The effect is 
surely not more noble than the cause, the child than its parent. 
If one part of the motion engendered, that is, the heat, is 
retransformed into the other kind, the change can be no degra- 
dation. The working power cannot be lost. It is rather re- 
stored, and only passes beyond our human control. It provides 
fora renewal of work in some other form. Even in our farms, 
