What is "humidifying"

Usage examples of "humidifying".

He promptly thrust one leg far out, flipped up the lid of the radiator cover, and emptied the cup into the humidifying pan below.

Stumbling to and fro among them, weighed down by the humidifying equipment that kept him alive if not entirely comfortable, he noted their sideways stares and heard their murmurings of disapproval.

It also had its own auxiliary heat and humidifying source to make sure it, too, stayed at the proper temperature and humidity.

That facility and this attic featured museum-quality heating and humidifying systems to ensure the least possible deterioration of the items in the collection.