The voice, in ordinary tones, carried perfectly; and yet in that small space nearly 7,000 H.P.were being produced and transmitted to the propellers and to the storage batteries that operated helicopters and compressed-air system, as well as the lighting-plant of the air-liner.
As the two men entered the engine-room, the Master nodded to Auchincloss.

He stood a moment gazing at the brightly flecked metal of the engines, the gleaming walls--hollow and filled with noninflammable helium gas of great lifting power--the men on watch over all this splendid mechanism.

Then he passed between engines No.

4 and No.

5, toward the aft wall of the compartment.
Four doors opened in the bulkhead, there.