The girl was given but brief opportunity for further observation of the pitiful creatures in the enclosure as her captor, after having directed the others to return to the fields, led her toward the tower, which they entered, passing into an apartment about ten feet wide and twenty long, in one end of which was a stairway leading to an upper level and in the other an opening to a similar stairway leading downward.  The chamber, though on a level with the ground, was brilliantly lighted by windows in its inner wall, the light coming from a circular court in the center of the tower.  The walls of this court appeared to be faced with what resembled glazed, white tile and the whole interior of it was flooded with dazzling light, a fact which immediately explained to the girl the purpose of the glass prisms of which the domes were constructed.  The stairways themselves were sufficient to cause remark, since in nearly all Barsoomian architecture inclined runways are utilized for purposes of communication between different levels, and especially is this true of the more ancient forms and of those of remote districts where fewer changes have come to alter the customs of antiquity.

Down the stairway her captor led Tara of Helium.  Down and down through chambers still lighted from the brilliant well.  Occasionally they passed others going in the opposite direction and these always stopped to examine the girl and ask questions of her captor.

“I know nothing but that she was found in the fields and that I caught her after a fight in which she slew two rykors and in which I slew a Moak, and that I take her to Luud, to whom, of course, she belongs.  If Luud wishes to question her that is for Luud to do—­not for me.”  Thus always he answered the curious.

Presently they reached a room from which a circular tunnel led away from the tower, and into this the creature conducted her.  The tunnel was some seven feet in diameter and flattened on the bottom to form a walk.  For a hundred feet from the tower it was lined with the same tile-like material of the light well and amply illuminated by reflected light from that source.  Beyond it was faced with stone of various shapes and sizes, neatly cut and fitted together—­a very fine mosaic without a pattern.  There were branches, too, and other tunnels which crossed this, and occasionally openings not more than a foot in diameter; these latter being usually close to the floor.  Above each of these smaller openings was painted a different device, while upon the walls of the larger tunnels at all intersections and points of convergence hieroglyphics appeared.  These the girl could not read though she guessed that they were the names of the tunnels, or notices indicating the points to which they led.  She tried to study some of them out, but there was not a character that was familiar to her, which seemed strange, since, while the written languages of the various nations of Barsoom differ, it still is true that they have many characters and words in common.