When Iburn this combustible for the manufacture of sodium,the smoke,escaping from the crater of the mountain,gives it the appearance of a still-active volcano.""And we shall see your companions at work?""No;not this time at least;for Iam in a hurry to continue our submarine tour of the earth.So Ishall content myself with drawing from the reserve of sodium Ialready possess.
The time for loading is one day only,and we continue our voyage.
So,if you wish to go over the cavern and make the round of the lagoon,you must take advantage of to-day,M.Aronnax."Ithanked the Captain and went to look for my companions,who had not yet left their cabin.Iinvited them to follow me without saying where we were.
They mounted the platform.Conseil,who was astonished at nothing,seemed to look upon it as quite natural that he should wake under a mountain,after having fallen asleep under the waves.But Ned Land thought of nothing but finding whether the cavern had any exit.
After breakfast,about ten o'clock,we went down on to the mountain.
"Here we are,once more on land,"said Conseil.
"Ido not call this land,"said the Canadian."And besides,we are not on it,but beneath it."Between the walls of the mountains and the waters of the lake lay a sandy shore which,at its greatest breadth,measured five hundred feet.
On this soil one might easily make the tour of the lake.But the base of the high partitions was stony ground,with volcanic locks and enormous pumice-stones lying in picturesque heaps.All these detached masses,covered with enamel,polished by the action of the subterraneous fires,shone resplendent by the light of our electric lantern.The mica dust from the shore,rising under our feet,flew like a cloud of sparks.
The bottom now rose sensibly,and we soon arrived at long circuitous slopes,or inclined planes,which took us higher by degrees;but we were obliged to walk carefully among these conglomerates,bound by no cement,the feet slipping on the glassy crystal,felspar,and quartz.
The volcanic nature of this enormous excavation was confirmed on all sides,and Ipointed it out to my companions.
"Picture to yourselves,"said I,"what this crater must have been when filled with boiling lava,and when the level of the incandescent liquid rose to the orifice of the mountain,as though melted on the top of a hot plate.""Ican picture it perfectly,"said Conseil."But,sir,will you tell me why the Great Architect has suspended operations,and how it is that the furnace is replaced by the quiet waters of the lake?""Most probably,Conseil,because some convulsion beneath the ocean produced that very opening which has served as a passage for the Nautilus.
Then the waters of the Atlantic rushed into the interior of the mountain.
There must have been a terrible struggle between the two elements,a struggle which ended in the victory of Neptune.But many ages have run out since then,and the submerged volcano is now a peaceable grotto.""Very well,"replied Ned Land;"Iaccept the explanation,sir;but,in our own interests,Iregret that the opening of which you speak was not made above the level of the sea.""But,friend Ned,"said Conseil,"if the passage had not been under the sea,the Nautilus could not have gone through it."We continued ascending.The steps became more and more perpendicular and narrow.Deep excavations,which we were obliged to cross,cut them here and there;sloping masses had to be turned.
We slid upon our knees and crawled along.But Conseil's dexterity and the Canadian's strength surmounted all obstacles.
At a height of about 31feet the nature of the ground changed without becoming more practicable.To the conglomerate and trachyte succeeded black basalt,the first dispread in layers full of bubbles,the latter forming regular prisms,placed like a colonnade supporting the spring of the immense vault,an admirable specimen of natural architecture.Between the blocks of basalt wound long streams of lava,long since grown cold,encrusted with bituminous rays;and in some places there were spread large carpets of sulphur.
