The least I could do, however, was to appease Eveena's fear before turning my attention to the objects of my own curiosity.

The presence of physical strength, which seemed to her superhuman, produced upon her nerves the quieting effect which, however irrationally, great bodily force always exercises over women; partly, perhaps, from the awe it seems to inspire, partly from a yet more unreasonable but instinctive reliance on its protection even in dangers against which it is obviously unavailing.
Presently a current of air, distinctly warmer than that of the tunnel, which had been gradually increasing in force for some minutes, became so powerful that I could no longer suppose it accidental.

Kevima being near us, I asked him what it meant.
"Ventilation," he answered.

"The air in these tunnels would be foul and stagnant, perhaps unbreathable, if we did not drive a constant current of air through them.

You did not notice, a few yards from the entrance, a wheel which drives a large fan.