Definition of "dews"

This is followed by a deluge of rain for an hour or two. Dews are very copious,– fogs little known. The climate is very salubrious.

1837 January 7, Colonel Sykes, “The British Assocation. Seventh Meeting: Liverpool”, in The Literary gazette and journal of the belles lettres, arts, sciences, &c‎, number 1042, W.A. Scripps, page 606

“The trail is fresh,” continued the chief; “not more than two dews have fallen on the prints of foot and hoof”

1844, Charles Augustus Murray, The Prarie-Bird‎, volume 3, published 2009, page 10