She soon, however, perceived a change in his air and behaviour that
extremely astonished her: he looked grave and thoughtful, saluted her
at a distance, shewed no sign of any intention to approach her,
regarded the dancing and dancers as a public spectacle in which he had
no chance of personal interest, and seemed wholly altered, not merely
with respect to her, but to himself, as his former eagerness for her
society was not more abated than [his] former general gaiety.

She had no time, however, for comments, as she was presently called to
the second cotillon; but the confused and unpleasant ideas which,
without waiting for time or reflection, crowded upon her imagination
on observing his behaviour, were not more depressing to herself, than
obvious to her partner; Mr Monckton by the change in her countenance
first perceived the entrance of young Delvile, and by her apparent
emotion and uneasiness, readily penetrated into the state of her
mind; he was confirmed that her affections were engaged; he saw, too,
that she was doubtful with what return.

The grief with which he made the first discovery, was somewhat
lessened by the hopes he conceived from, the second; yet the evening
was to him as painful as to Cecilia, since he now knew that whatever
prosperity' might ultimately attend his address and assiduity, her
heart was not her own to bestow; and that even were he sure of young
Delvile's indifference, and actually at liberty to make proposals for
himself, the time of being first in her esteem was at an end, and the
long-earned good opinion which he had hoped would have ripened into
affection, might now be wholly undermined by the sudden impression of
a lively stranger, without trouble to himself, and perhaps without
pleasure!