QUESTION AND ANSWER

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"By Jove!" said he, "it must be hot up there!"

"Without considering," replied Nicholl, "that the day lasts 360 hours!"

"And to compensate that," said Barbicane, "the nights have the same length; and as heat is restored by radiation, their temperature can only be that of the planetary space."

"A pretty country, that!" exclaimed Michel. "Never mind! I wish I was there! Ah! my dear comrades, it will be rather curious to have the earth for our moon, to see it rise on the horizon, to recognize the shape of its continents, and to say to oneself, `There is America, there is Europe;' then to follow it when it is about to lose itself in the sun's rays! By the bye, Barbicane, have the Selenites eclipses?"

"Yes, eclipses of the sun," replied Barbicane, "when the centers of the three orbs are on a line, the earth being in the middle. But they are only partial, during which the earth, cast like a screen upon the solar disc, allows the greater portion to be seen."

"And why," asked Nicholl, "is there no total eclipse? Does not the cone of the shadow cast by the earth extend beyond the moon?"

"Yes, if we do not take into consideration the refraction produced by the terrestrial atmosphere. No, if we take that refraction into consideration. Thus let [lower case delta] be the horizontal parallel, and p the apparent semidiameter----"

"Oh!" said Michel. "Do speak plainly, you man of algebra!"

"Very well, replied Barbicane; "in popular language the mean distance from the moon to the earth being sixty terrestrial radii, the length of the cone of the shadow, on account of refraction, is reduced to less than forty-two radii. The result is that when there are eclipses, the moon finds itself beyond the cone of pure shadow, and that the sun sends her its rays, not only from its edges, but also from its center."

"Then," said Michel, in a merry tone, "why are there eclipses, when there ought not to be any?"

"Simply because the solar rays are weakened by this refraction, and the atmosphere through which they pass extinguished the greater part of them!"

"That reason satisfies me," replied Michel. "Besides we shall see when we get there. Now, tell me, Barbicane, do you believe that the moon is an old comet?"

"There's an idea!"

"Yes," replied Michel, with an amiable swagger, "I have a few ideas of that sort."

"But that idea does not spring from Michel," answered Nicholl.

"Well, then, I am a plagiarist."

"No doubt about it. According to the ancients, the Arcadians pretend that their ancestors inhabited the earth before the moon became her satellite. Starting from this fact, some scientific men have seen in the moon a comet whose orbit will one day bring it so near to the earth that it will be held there by its attraction."

"Is there any truth in this hypothesis?" asked Michel.

"None whatever," said Barbicane, "and the proof is, that the moon has preserved no trace of the gaseous envelope which always accompanies comets."