Definition of "ardour"

I rushed towards her, and embraced her with ardour; but the deathly languor and coldness of the limbs told me, that what I now held in my arms had ceased to be the Elizabeth whom I had loved and cherished.

1818, [Mary Shelley], chapter VI, in Frankenstein; or, The Modern Prometheus. […], volume III, London: […] [Macdonald and Son] for Lackington, Hughes, Harding, Mavor, & Jones, page 120

The purpose of my visit, and the frightful abnormalities it postulated struck at me all at once with a chill sensation that nearly over-balanced my ardour for strange delvings.

1931, H. P. Lovecraft, chapter 6, in The Whisperer in Darkness