412 THE GEOLOGIST. 



greatly backward in time the epochs of remarkable events, of which 

 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? We 

 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 off ; 

 no doubt it has — very much farther off ; 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 

 off 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 1 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 



