ow the Sun to be eclipsed altogether. Even when completely
screened by the Earth, he would form a beautiful circle around her of
yellow, red, and crimson light, in which she would appear to float like
a vast sphere of jet in a glowing sea of gold, rubies, sparkling
carbuncles and garnets."

"It seems to me," said M'Nicholl, "that, taking everything into
consideration, the invisible side has been rather shabbily treated."

"I know I should not stay there very long," said Ardan; "the desire of
seeing such a splendid sight as that eclipse would be enough to bring me
to the visible side as soon as possible."

"Yes, I have no doubt of that, friend Michael," pursued Barbican; "but
to see the eclipse it would not be necessary to quit the dark hemisphere
altogether. You are, of course, aware that in consequence of her
librations, or noddings, or wobblings, the Moon presents to the eyes of
the Earth a little more than the exact half of her disc. She has two
motions, one on her path around the Earth, and the other a shifting
around on her own axis by which she endeavors to keep the same side
always turned towards our sphere. This she cannot always do, as while
one motion, the latter, is strictly uniform, the other being eccentric,
sometimes accelerating her and sometimes retarding, she has not time to
shift herself around completely and with perfect correspondence of
movement. At her perigee, for instance, she moves forward quicker than
she can shift, so that we detect a portion of her western border before
she has time to conceal it. Similarly, at her apogee, when her rate of
motion is comparatively slow, she shifts a little too quickly for her
velocity, and therefore cannot help revealing a certain portion of her
eastern border. She shows altogether about 8 degrees of the dark side,
about 4 at the east and 4 at the west, so that, out of her 360 degrees,
about 188, in other words, a little more than 57 per cent., about 4/7 of
the entire surface, becomes visible to human eyes. Consequently a
Selenite could catch an occasional glimpse of our Earth, without
altogether quitting the dark side."

"No matter for that!" cried Ardan; "if we ever become Selenites we must
inhabit the visible side. My weak point is light, and that I must have
when it can be got."

"Unless, as perhaps in this case, you might be paying too dear for it,"
observed M'Nicholl. "How would you like to pay for your light by the
loss of the atmosphere, which, ac