Each door opened with a key, like a cupboard.
Steinmetz had apparently finished his work.

He was sitting back in his chair, contemplating his companion with a little smile.

It apparently tickled some obtuse Teutonic sense of humor to see this prince doing work which is usually assigned to clerks--working out statistics and abstruse calculations as to how much food is required to keep body and soul together.
The silence of the room was almost oppressive.

A Russian village after nightfall is the quietest human habitation on earth.

For the moujik--the native of a country which will some day supply the universe with petroleum--cannot afford to light up his humble abode, and therefore sits in darkness.