"And as the operation of ventilating the room, even when it is done in the most complete manner, will never require the door and window to be open more than one minute; in this short time the walls of the room will not be sensibly cooled, and the fresh air which comes into the room will, in a very few minutes, be so completely warmed by these walls that the temperature of the room, though the air in it be perfectly changed, will be brought to be very nearly the same as it was before the ventilation."