https://www.scientificamerican.com/article/firefighter-suit-draws-breathable-air-from-the-floor/

“In apartments filled with smoke to an extent that would render it impossible to breathe at the height of a person’s head above the floor, there is in nearly every instance a draft of cool, pure air near the floor. To take advantage of this circumstance a tight-fitting mask has been adapted, from which depend air tubes, through which a person breathes; the extremities of the tubes reach to within an inch or two of the floor.”

—Scientific American, July 1857