CHAPTER XII
OROGRAPHIC DETAILS
The course taken by the projectile, as we have before remarked, wasbearing it toward the moon's northern hemisphere. The travelerswere far from the central point which they would have struck,had their course not been subject to an irremediable deviation.It was past midnight; and Barbicane then estimated the distanceat seven hundred and fifty miles, which was a little greater thanthe length of the lunar radius, and which would diminish as itadvanced nearer to the North Pole. The projectile was then notat the altitude of the equator; but across the tenth parallel,and from that latitude, carefully taken on the map to the pole,Barbicane and his two companions were able to observe the moonunder the most favorable conditions. Indeed, by means of glasses,the above-named distance was reduced to little more thanfourteen miles. The telescope of the Rocky Mountains broughtthe moon much nearer; but the terrestrial atmosphere singularlylessened its power. Thus Barbicane, posted in his projectile,with the glasses to his eyes, could seize upon details which werealmost imperceptible to earthly observers.
"My friends," said the president, in a serious voice, "I do notknow whither we are going; I do not know if we shall ever seethe terrestrial globe again. Nevertheless, let us proceed as ifour work would one day by useful to our fellow-men. Let us keepour minds free from every other consideration. We areastronomers; and this projectile is a room in the CambridgeUniversity, carried into space. Let us make our observations!"
This said, work was begun with great exactness; and theyfaithfully reproduced the different aspects of the moon,at the different distances which the projectile reached.
At the time that the projectile was as high as the tenthparallel, north latitude, it seemed rigidly to follow thetwentieth degree, east longitude. We must here make oneimportant remark with regard to the map by which they weretaking observations. In the selenographical maps where, onaccount of the reversing of the objects by the glasses, thesouth is above and the north below, it would seem natural that,on account of that inversion, the east should be to the lefthand, and the west to the right. But it is not so. If the mapwere turned upside down, showing the moon as we see her, theeast would be to the left, and the west to the right, contraryto that which exists on terrestrial maps. The following is thereason of this anomaly. Observers in the northern hemisphere(say in Europe) see the moon in the south-- according to them.When they take observations, they turn their backs to the north,the reverse position to that which they occupy when they studya terrestrial map. As they turn their backs to the north, theeast is on their left, and the west to their right. To observersin the southern hemisphere (Patagonia for example), the moon'swest would be quite to their left, and the east to their right,as the south is behind them. Such is the reason of the apparentreversing of these two cardinal points, and we must bear it in mindin order to be able to follow President Barbicane's observations.
With the help of Boeer and Moedler's _Mappa Selenographica_,the travelers were able at once to recognize that portionof the disc enclosed within the field of their glasses.
"What are we looking at, at this moment?" asked Michel.
"At the northern part of the `Sea of Clouds,'" answered Barbicane."We are too far off to recognize its nature. Are these plainscomposed of arid sand, as the first astronomer maintained?Or are they nothing but immense forests, according to M. Warrende la Rue's opinion, who gives the moon an atmosphere, thougha very low and a very dense one? That we shall know by and by.We must affirm nothing until we are in a position to do so."
This "Sea of Clouds" is rather doubtfully marked out upon the maps.It is supposed that these vast plains are strewn with blocks oflava from the neighboring volcanoes on its right, Ptolemy,Purbach, Arzachel. But the projectile was advancing, and sensiblynearing it. Soon there appeared the heights which bound this seaat this northern limit. Before them rose a mountain radiant withbeauty, the top of which seemed lost in an eruption of solar rays.
"That is--?" asked Michel.
"Copernicus," replied Barbicane.
"Let us see Copernicus."
This mount, situated in
[email protected] north latitude and
[email protected] eastlongitude, rose to a height of 10,600 feet above the surface ofthe moon. It is quite visible from the earth; and astronomerscan study it with ease, particularly during the phase betweenthe last quarter and the new moon, because then the shadows arethrown lengthways from east to west, allowing them to measurethe heights.
This Copernicus forms the most important of the radiatingsystem, situated in the southern hemisphere, according to TychoBrahe. It rises isolated like a gigantic lighthouse on thatportion of the "Sea of Clouds," which is bounded by the "Sea ofTempests," thus lighting by its splendid rays two oceans ata time. It was a sight without an equal, those long luminoustrains, so dazzling in the full moon, and which, passing theboundary chain on the north, extends to the "Sea of Rains."At one o'clock of the terrestrial morning, the projectile,like a balloon borne into space, overlooked the top of thissuperb mount. Barbicane could recognize perfectly itschief features. Copernicus is comprised in the series ofringed mountains of the first order, in the division ofgreat circles. Like Kepler and Aristarchus, which overlookthe "Ocean of Tempests," sometimes it appeared like a brilliantpoint through the cloudy light, and was taken for a volcanoin activity. But it is only an extinct one-- like all on thatside of the moon. Its circumference showed a diameter of abouttwenty-two leagues. The glasses discovered traces ofstratification produced by successive eruptions, and theneighborhood was strewn with volcanic remains which still chokedsome of the craters.
"There exist," said Barbicane, "several kinds of circles on thesurface of the moon, and it is easy to see that Copernicusbelongs to the radiating class. If we were nearer, we shouldsee the cones bristling on the inside, which in former timeswere so many fiery mouths. A curious arrangement, and onewithout an exception on the lunar disc, is that the interiorsurface of these circles is the reverse of the exterior, andcontrary to the form taken by terrestrial craters. It follows,then, that the general curve of the bottom of these circlesgives a sphere of a smaller diameter than that of the moon."
"And why this peculiar disposition?" asked Nicholl.
"We do not know," replied Barbicane.
"What splendid radiation!" said Michel. "One could hardly seea finer spectacle, I think."
"What would you say, then," replied Barbicane, "if chance shouldbear us toward the southern hemisphere?"
"Well, I should say that it was still more beautiful," retortedMichel Ardan.
At this moment the projectile hung perpendicularly over the circle.The circumference of Copernicus formed almost a perfect circle,and its steep escarpments were clearly defined. They could evendistinguish a second ringed enclosure. Around spread a grayishplain, of a wild aspect, on which every relief was marked in yellow.At the bottom of the circle, as if enclosed in a jewel case,sparkled for one instant two or three eruptive cones, like enormousdazzling gems. Toward the north the escarpments were lowered by adepression which would probably have given access to the interiorof the crater.
In passing over the surrounding plains, Barbicane noticed agreat number of less important mountains; and among others alittle ringed one called Guy Lussac, the breadth of whichmeasured twelve miles.
Toward the south, the plain was very flat, without oneelevation, without one projection. Toward the north, on thecontrary, till where it was bounded by the "Sea of Storms," itresembled a liquid surface agitated by a storm, of which thehills and hollows formed a succession of waves suddenly congealed.Over the whole of this, and in all directions, lay the luminouslines, all converging to the summit of Copernicus.
The travelers discussed the origin of these strange rays; but theycould not determine their nature any more than terrestrial observers.
"But why," said Nicholl, "should not these rays be simply spursof mountains which reflect more vividly the light of the sun?"
"No," replied Barbicane; "if it was so, under certa
in conditionsof the moon, these ridges would cast shadows, and they do notcast any."
And indeed, these rays only appeared when the orb of day was inopposition to the moon, and disappeared as soon as its raysbecame oblique.
"But how have they endeavored to explain these lines of light?"asked Michel; "for I cannot believe that savants would ever bestranded for want of an explanation."
"Yes," replied Barbicane; "Herschel has put forward an opinion,but he did not venture to affirm it."
"Never mind. What was the opinion?"
"He thought that these rays might be streams of cooled lavawhich shone when the sun beat straight upon them. It may be so;but nothing can be less certain. Besides, if we pass nearer toTycho, we shall be in a better position to find out the cause ofthis radiation."
"Do you know, my friends, what that plain, seen from the heightwe are at, resembles?" said Michel.
"No," replied Nicholl.
"Very well; with all those pieces of lava lengthened like rockets,it resembles an immense game of spelikans thrown pellmell.There wants but the hook to pull them out one by one."
"Do be serious," said Barbicane.
"Well, let us be serious," replied Michel quietly; "and insteadof spelikans, let us put bones. This plain, would then benothing but an immense cemetery, on which would repose themortal remains of thousands of extinct generations. Do youprefer that high-flown comparison?"
"One is as good as the other," retorted Barbicane.
"My word, you are difficult to please," answered Michel.
"My worthy friend," continued the matter-of-fact Barbicane, "itmatters but little what it _resembles_, when we do not know whatit _is_."
"Well answered," exclaimed Michel. "That will teach me toreason with savants."
But the projectile continued to advance with almost uniformspeed around the lunar disc. The travelers, we may easilyimagine, did not dream of taking a moment's rest. Every minutechanged the landscape which fled from beneath their gaze.About half past one o'clock in the morning, they caught a glimpseof the tops of another mountain. Barbicane, consulting his map,recognized Eratosthenes.
It was a ringed mountain nine thousand feet high, and one ofthose circles so numerous on this satellite. With regard tothis, Barbicane related Kepler's singular opinion on theformation of circles. According to that celebratedmathematician, these crater-like cavities had been dug by thehand of man.
"For what purpose?" asked Nicholl.
"For a very natural one," replied Barbicane. "The Selenitesmight have undertaken these immense works and dug these enormousholes for a refuge and shield from the solar rays which beatupon them during fifteen consecutive days."
"The Selenites are not fools," said Michel.
"A singular idea," replied Nicholl; "but it is probable thatKepler did not know the true dimensions of these circles, forthe digging of them would have been the work of giants quiteimpossible for the Selenites."
"Why? if weight on the moon's surface is six times less than onthe earth?" said Michel.
"But if the Selenites are six times smaller?" retorted Nicholl.
"And if there are _no_ Selenites?" added Barbicane.
This put an end to the discussion.
Soon Eratosthenes disappeared under the horizon without theprojectile being sufficiently near to allow close observation.This mountain separated the Apennines from the Carpathians. In thelunar orography they have discerned some chains of mountains, whichare chiefly distributed over the northern hemisphere. Some, however,occupy certain portions of the southern hemisphere also.
About two o'clock in the morning Barbicane found that they wereabove the twentieth lunar parallel. The distance of theprojectile from the moon was not more than six hundred miles.Barbicane, now perceiving that the projectile was steadilyapproaching the lunar disc, did not despair; if not of reachingher, at least of discovering the secrets of her configuration.