"[N]o form of the funnel of the chimney has any share in its operation or effect respecting smoke, except its height. The longer the funnel if erect, the greater its force when filled with heated and rarefied air, to draw in below and drive up the smoke (if one may in compliance with custom use the expression draw), when in fact it is the superior weight of the surrounding atmosphere that presses to enter the funnel below, and so drives up... the smoke and warm air..."