https://www.scientificamerican.com/article/every-student-needs-200-cubic-feet-of-air/

“An ideal school room should provide fteen square feet of floor space for each pupil and a supply of 200 cubic feet of air per minute for every person in the room. Such provisions would ensure the free movement of every child and a wholesome amount of air. In France, the perfect school room, it is thought, should have a window area equal to one-fourth the floor space. It is also thought best to have individual seats and desks for the pupils.”

—Scientific American, April 1895