Intent upon artistic matters, the old man was hardly aware, either, that Marietta had learned much of his art; or if he realised the fact he felt a sort of jealous satisfaction in the thought that she liked to be shut up with him for hours at a time, quite out of sight of the world and altogether out of harm's way.

He fancied that she grew more like him from day to day, and he flattered himself that he understood her.

She and Zorzi were the only beings in his world who never irritated him, now that he had them always under his eye and command.

It was natural that he should suppose himself to be profoundly acquainted with their two natures, though he had never taken the smallest pains to test this imaginary knowledge.

Possibly, in their different ways, they knew him better than he knew them.
The glass-house was guarded from outsiders as carefully as a nunnery, and somewhat resembled a convent in having no windows so situated that curious persons might see from without what went on inside.