70 
manure and sewage are utilized, and turned into sources of 
increased fertility. Man’s range of power is limited, and out 
great sewage problem is still unsolved. But the poweis of 
nature have a far wider range. In spite ot desponding theoiies, 
we may be perfectly sure that there is no real waste-heap in 
God’s glorious universe. 
The main fault of the doctrine lies here. Matter and ether 
need three laws to determine their mutual action. The action 
of matter on matter is known, the law of gravitation. Out of 
this law, applied to a vast, diffused, finite system of matter, 
the nebular theory has grown. It accounts, by the working of 
that law on such a nebula, for many leading phenomena of our 
solar system; The action, again, of ether on ether, though its 
law is not known, must be self-repulsive, in order to explain its 
nearly equal diffusion. If it condensed into patches, the trans- 
mission of light would cease. Out of this law grows the 
doctrine of dissipation. Heat, or atomic motion, if impressed on 
the ether, must be transmitted in all directions with the speed 
of light. The limit to which this action tends is complete 
equahty. Hot bodies must grow cool, and cool bodies be 
heated, till the balance is restored. But in this reasoning the 
third law, also unknown, but certainly attractive, the mutual 
action of matter and ether, is left out of sight and forgotten. 
Yet it is one most essential element in the problem. Without 
some law of this kind, the atomic heat could not affect the 
ambient ether at all, and there could be no radiation. 
The doctrine that the total amount of heat never changes, 
and that its transmission is in proportion to difference of tem- 
perature, cannot be absolutely true. It is only a relic of 
the now exploded theory, that caloric is a distinct and peculiar 
substance. 
When light and heat travel from an incandescent body 
through space, the most palpable result is to heat the solM 
bodies within its range. So far there is a simple transfer of 
heat, and nearly in the ratio of the excess of temperature. But 
is this the sole effect? Does no part exercise a repellent 
power, and become reconverted into increased distance or dila- 
tation? The answer should have been plain to the eye of science 
from the first. Within a few months it has received a striking 
experimental confirmation. What means the rotation of the 
blackened discs in that new-invented instrument, the radio- 
meter ? Surely, that one effect of radiant heat and light is 
direct repulsion, by which the bodies on which it falls must 
be driven a little further from the source of that radiation. 
This is not the whole truth. Clouds, it is known, tend to 
