Which preposition to use with chillier

as Occurrences 1%

But Willie held on, directed by some instinct, it seemed, over that awful shell-fragment-studded mire, round the verges of shell-formed craters, past dead and wounded waiting for succouron, on, till the very guns seemed to have grown weary, and the rain ceased, and the air grew chillier as with dread of what the dawn should disclose, and the blackness was diluted to grey.

Which preposition to use with  chillier