What is carbonic acid gas?
It is the gas most dangerous to health, it being most common, and should be guarded against by means of proper ventilation. It being one of the heavy gases, it naturally falls, and will be found in the lower strata of air in a room. For this reason the ventilation of public buildings and living rooms should be from the lower part of the room near the floor. By placing the ventilation near the floor, we not only assist in correcting this evil, but by drawing in the cold air from the lower section of the room, the heated air of the upper sections is forced to fall, to fill this space. Thus a proper circulation of air in the room is established. Years ago, when houses were heated from fireplaces, headaches were seldom known, which was largely due to this same manner of ventilation.
