When the long working day at last drew to a close the slaves were conducted to their quarters, which, as Tarzan discovered, were always on levels near to those in which they labored. He, with several other slaves, was conducted to the thirty-fifth level and into a tunnel the far end of which had been widened to the proportions of a large chamber, the narrow entrance to which had been walled up with stone except for a small aperture through which the slaves were forced to pass in and out of their chamber upon all fours, and when the last of them was within, this was closed and secured by a heavy door outside which two warriors watched throughout the night.
Once inside and standing upon his feet the ape-man looked about him to discover himself within a chamber so large that it seemed easy to accommodate the great throng of slaves that must have numbered fully five thousand souls of both sexes. The women were preparing food over small fires the smoke of which found its way from the chamber through openings in the ceiling. For the great number of fires the amount of smoke was noticeably little, a fact which was, however, accounted for by the nature of the fuel, a clean, hard charcoal; but why the liberated gases did not asphyxiate them all was quite beyond the apeman, as was still the riddle of the open flames and the pure air at the depth where the workings lay. Candles burned in niches all about the walls and
