71 
disappear under the light of the full moon. So it is clear that 
some part of the energy in the sun’s light and heat will be 
spent in rarefying any nebulous patches, thicker than the rest, 
in the thin and rare matter of the planetary spaces through 
which it travels. 
Again, by the laws of mechanics, some part, and probably 
the main part, must be spent in creating ethereal currents. 
Disturbed ether will have a greater mutual repulsion than 
ether undisturbed. The motion, in mechanical effect, will be 
equivalent to an increased density. That the repulsive action 
may be equal everywhere, the ether will be thinned where the 
disturbance is greatest, and become denser in all other parts 
of the system. 
These three changes limit and modify the doctrine of the equal 
diffusion of heat, and should have been clear to students of 
physics, as soon as the Baconian view of heat was re-established. 
I have expressed them at the close of my work on Matter 
and Ether, published fourteen years ago. One of them has 
now, within a few months, been made patent to the senses 
of all men. They disprove that doctrine of the ceaseless dis- 
sipation of energy, which we find in so many recent works 
of science, and replace it by a doctrine essentially different, — 
its ceaseless circulation. 
The view of Mayer, that solar heat is kept up mainly by the 
dropping in of meteors, is now abandoned by its late adhe- 
rents. It has died an early death. The suggested cause is 
too irregular, fitful, and uncertain, to account for the grand 
fact of ceaseless solar radiation. And thei’e isithis further objec- 
tion, that the consequent increase of the central mass must 
have shortened the year by one or two hours in the course of 
the last four thousand years. 
The theory of Helmholtz is now in vogue, which would 
supply the constant waste in radiation from the further con- 
traction of the solar mass, and not its increase. But this, I 
believe, admits of almost as plain a disproof as the other. For 
what result must follow ? The heat and light would then be 
greatest vdien the contraction is most rapid, that is, in the 
earliest stages of condensation. But all the known facts and 
known analogies point the opposite way. The more nebulous 
a star, the smaller and dimmer its light. The most luminous, 
like Sirius, are those which appear to have most distinctly a 
fully-condensed central body, like our sun. If the radiant 
energy were lost in the depths of space as soon as generated, 
how could the light and heat of the sun have ever reached their 
present amount ? 
