Such questions, at such an hour, were bound to drift through his mind; but he was conscious that their uncomfortable persistence and precision were due to the inopportune arrival of the Countess Olenska.
There are no more uses of "persistence" in the book.
Show samples from other sources
The majority of men meet with failure because of their lack of persistence in creating new plans to take the place of those which fail.
The art of love ... is largely the art of persistence.