Taking the experiments as a whole, it will be seen that in a flue 6
inches in diameter, the maximum speed of current which can be obtained
with economy is about 200 feet per minute; and this was realized with a
gas consumption of 1 cubic foot per hour—1 cubic foot of gas removing
2,460 cubic feet of air.
It should, however, not be required of any system of heating to more
than aid in ventilation. It is the architect’s or builder’s performance
to so arrange lower and upper openings to drive out the bad air.