412 THE GEOLOGIST. 
greatly backward in time the epoclis of remarkable events, of which 1^ 
the traditions have reached us from a very remote antiquity indeed. It 
is even possible that such traditions may extend back to the Pliocene 
period, in which seemingly, if not before, the age of man began. But 
we leave this subject alone, and return to the question — What has 
become of the waters of the moon ? The ocean-cavities, if they were 
once filled, must have been emptied. What emptied them? Woj 
know that year by year the moon gets nearer to us ; it may be only^ 
half an inch, and astronomers even dispute whether it is more than a 
quarter ; but nearer, we believe, it does come. We know also that 
such changes are said to correct themselves, but we cannot say there 
is not a residual balance in favour of approach. There is good reason 
to consider that nothing in the whole universe is stable, although the 
changes are so slowly grand that centuries of observation are insuf- 
ficient to prove their rate. Still we may believe the moon has come 
nearer the earth. If it comes nearer, it has once been farther ofi*; 
no doubt it has — very much farther ofi" ; and then it was it had its. 
atmosphere and its oceans. Then the great Oceanus Procellarum 
was a rolling sea, and the Mare Serenitatis lay glittering under the 
golden streaks of our earth's bright beams, and clouds floated in, and 
storms disturbed the encircling atmosphere. But when the moon, 
gradually diminishing her distance, came sufficiently within the 
influence of the earth's attraction, did its superior gravitation draw 
ofi* her moist atmosphere towards its own, and make a roadway of 
thin air, along which clouds of the most highly rarified watery vapours 
might travel earthwards ? With the diminished pressure, consequent 
on the partial loss of atmosphere, the water on the moon's proximate 
surface would more and more quickly evaporate ; for just as water 
boils on one of our mountain peaks with less heat, as the pressure 
of our air diminishes, or as warm water boils in a vacuum, so 
would the reduction of atmospheric pressure by the earth's attraction 
of her atmosphere, and the continued loss of vapour cause a most 
rapid evaporation of her seas, and clouds of highly rarified water would 
roll along the aerial way, and mingle with those in our skies. The 
waters of the moon might thus be transported to our globe, and 
carried by strong and sweeping currents all around, while the lunar 
vapours, in condensing, would fall in torrential rains over the whole 
