Entertaining as these discoveries and discussions might be, however, the feeling that they had stumbled into a region inhabited by a race of men who lived in a manner unknown to them--and who, moreover, had already given evidence of unfriendliness towards strangers--was not reassuring to Miranda or any of the rest of them. The end of their adventure grew every moment more puzzling. Since their escape from Anitoo they had not actually met any one. Perhaps this part of the cave was not inhabited after all. Perhaps Anitoo's talk of a queen was not to be taken too seriously. The curious objects projecting from the walls far above them might not be the human dwellings that at first sight they appeared. Even the signs of an unearthly vegetation might prove a sort of mirage, or they might turn out to be mere specimens of basaltic formation--fantastic enough, certainly--wrought by the subterranean convulsions that had given birth to this cave measureless ages ago. But the air had become so strangely invigorating, the mysterious light so pervasive and even brilliant, that anything seemed possible. This atmospheric vitality, a certain bracing quality in the air, had been noted, indeed, among their first experiences in the outer cave. But, compared with this that now tingled and coursed in their veins like some conquering elixir, the air of the outer cave was chill, dead. Here life might germinate and be sustained--although there lacked, as Miranda had pointed out, "the sun and rain" to aid in these daily miracles of nature. But it was idle to theorize, useless to harbor doubts that led nowhere. So, they wandered on, marveling at the strangeness and the magnitude of this underground world, and yielding themselves, as familiarity disarmed their fears, to the charm of it all. For there was beauty of a rare and thrilling quality in these majestic cliffs whose perfectly proportioned sides gleamed in all the variegations of color belonging to certain kinds of basalt. Displaying in structure the columnar forms peculiar to this rock, the admirable symmetry produced easily suggested the work of a human architect gifted in all the cunning of his art. And now the widening space before them disclosed unmistakable signs of the human agency they had suspected.