Also Tommy thrust his head from beneath the cloak with his tongue hanging out and his mouth wide open.
"Hold your breaths!" cried Yva, and we obeyed until we nearly burst.

At least I did, but what happened to the others I do not know.
Fortunately it was soon over and the air began to grow cool again.

By now we had travelled an enormous distance, it seemed to be miles on miles, and I noticed that our terrific speed was slackening, also that the shaft grew more narrow, till at length there were only a few feet between the edge of the stone and its walls.

The result of this, or so I supposed, was that the compressed air acted as a buffer, lessening our momentum, till at length the huge stone moved but very slowly.
"Be ready to follow me," cried Yva again, and we rose to our feet, that is, Bickley and I did, but poor Bastin was semi-comatose.

The stone stopped and Yva sprang from it to a rock platform level with which it lay.