Now that you have established the existence of your humanity in the Moon, the Chair would respectfully ask how it has all so completely disappeared ?" "It disappeared completely thousands, perhaps millions, of years ago," replied the unabashed Captain.

"It perished from the physical impossibility of living any longer in a world where the atmosphere had become by degrees too rare to be able to perform its functions as the great resuscitating medium of dependent existences.

What took place on the Moon is only what is to take place some day or other on the Earth, when it is sufficiently cooled off." "Cooled off ?" "Yes," replied the Captain as confidently and with as little hesitation as if he was explaining some of the details of his great machine-shop in Philadelphia; "You see, according as the internal fire near the surface was extinguished or was withdrawn towards the centre, the lunar shell naturally cooled off.

The logical consequences, of course, then gradually took place: extinction of organized beings; and then extinction of vegetation.

The atmosphere, in the meantime, became thinner and thinner--partly drawn off with the water evaporated by the terrestrial attraction, and partly sinking with the solid water into the crust-cracks caused by cooling.