Mad Barbara by Warwick Deeping

Set a thief to catch a thief, and a woman to unravel the character of a woman. Such was the aphorism my Lord Gore had bestowed in confidence upon Hortense when he had bequeathed Anne Purcell's daughter to the Italian's cleverness. If there were anything beneath that sullen and lethargic surface, Hortense would discover it, and perhaps resurrect the girl's instinct to laugh and live.

Few guests met in the painted salon that summer evening: three girls of Barbara's age, an elderly knight with sharp, humorous eyes, a sentimental widow, and Hortense. The windows were open toward the park, where dull, rain-ladened clouds shut out the stars. A few shaded candles in sconces along the walls made a glimmering twilight in the room, and in one corner a little brazen lamp burned perfumed oil, so that the air was richly scented.