dimmer than light at the surface of the sun.
As for the sun's heat,—that is to say, the
heat which radiates from it, leaving wholly
out of account the heat retained in its
substance—Professor Thomson, of Glasgow, has
expressed that vividly, by showing how much
coal it would take to generate it: thirteen
thousand five hundred pounds of coal must
be consumed every hour on every individual
square yard of the sun's surface. This allows
nothing for the heating of the sun itself. If
all this heat comes out of a conflagration, how
is it kept up? Professor Thomson ascribes
it to friction, Sir John Herschel to electricity.

As moonshine is sunshine transformed, we
must begin at the beginning. "May not,"
Sir John Herschel asks, "may not a continual
current of electric matter be constantly
circulating in the sun's immediate neighbourhood,
or traversing the planetary spaces; and,
exciting, in the upper regions of its
atmosphere, those phenomena of which, on
however diminutive a scale, we have yet an
unequivocal manifestation in our aurora
borealis? The possible analogy of the solar
light to that of the aurora has been distinctly
insisted on by the late Sir William Herschel."
This harmonises better than the friction
theory with what I have to say concerning
moonshine. The ray of sunshine is now said
to contain not only light and heat, but also
actinism. The light, white and pure as it
seems, has, since Newton's time, been known
to be a compound of lights varying not only
in colour, but refracting power. In these days,
we ascribe other differences to these coloured
lights than the mere obvious difference of
their places in the rainbow. We ascribe
light to the yellow rays; heat to the red and
to invisible rays beyond the red. Electrical
affinity and actinism, which is the main
producer of photographic or chemical action
(the power of decomposing salts of silver), we
ascribe to the blue rays, and to certain rays
beyond the blue, which are invisible to the
unaided eye: of these Professor Stokes was
the discoverer. The different heating powers
of the different lights in the spectrum, or
artificial rainbow, can be tried by the
thermometer. Sir Henry Englefield found that
when the thermometer, with its bulb in the
blue ray, stood at fifty-six degrees, in the green
ray it was two degrees warmer, in the yellow
ray six degrees warmer, in the red ray sixteen
degrees warmer, and beyond the red ray
twenty-three degrees warmer. The mercury
in the thermometer fell again when the bulb
was brought back into the red, from the
invisible light beyond it, which is a part of
sunshine; yet is, in the ordinary sense, no
light at all. All this is very wonderful; we
detect certain effects, and profit by them; but
we have not gone beyond a dim guess at
their causes. We talk of the triumphs of
our science; say that we compel the sun
himself to trade with us in pictures; but we
don't know what the sun is. Where it is and
how big it is we know, but what it is we do
not know. We don't so much as know
what sunshine is. It is almost the commonest
thing on earth; but we do not know why it
is light; why it is warm; why it is a complex
thing; and why its yellow rays are light, its
red rays warm, and its blue rays actinic. We
don't know the cause of that chemical power
which it pleases us to call actinism; nor do
we know why the actinic ray turns nitrate of
silver black. These blue rays are found to
be those which determine plants to grow
towards the light, but why do they so? If
we nail against a wall loose shoots of
honeysuckles so that their leaves show to the sun
their lower sides, the sun will turn them
round in a summer's day, and every leaf will
show its upper surface to the sunlight.
Everybody knows that to be so; but why,
remains to the wisest an unpenetrated
mystery.

Then we confess that there are mysteries
in sunshine, we acknowledge many more
than I have indicated here. My belief is, that
there are as many mysteries in moonshine
yet to be acknowledged and explored; and, in
both, some mysteries upon the trace of which
we are yet hardly come.

As to the moon's influence over the weather,
I take Mr. Glaisher's word that, at the
Greenwich Observatory, during the last
eighteen years, changes of weather have been
found to be as frequent at every age of the
moon, as when she has been seven, fourteen,
twenty-one, or twenty-eight days old; therefore
she cannot have had the slightest influence
over any of them. Monsieur Hagergues,
taking the number of rainy days that occur
on days of the moon's phases during nineteen
years, found most rain coincident with the
first quarter: least rain with the last. Monsieur
Schubler kept a like record for eight-
and-twenty years, and found most rain
coincident with days of full moon, least at the last
quarter. Doctor Marcet examined a register
of weather kept for thirty-four years at
Geneva, and found also most rain at the
period of full moon, but least at the time, not
of the last, but of the first quarter. Monsieur
Arago, comparing registers that covered a
long period, found least rain at the time of
full moon, most when the moon was new.
Doctor Marcet noted also changes of weather
from rain to fair and from fair to rain at
changes of the moon during his thirty-four
years, and found, he says, some support to
the vulgar opinion of the influence of new
and full moon: none whatever to a belief in
the influence of the two quarters. From
such conflicting notes of trivial differences,
science infers that the age of the moon makes
no practical difference at all to the state of
the weather. Obstinate still is the faith of
shepherds on our hills, of fishermen upon our
coasts, and of wives in our households. For
myself, I accept the calculations made by