"Those who will take the trouble to consider the nature and properties of elastic s,—of air,—smoke,—and vapour,—and to examine the laws of their motions, and the necessary consequences of their being rarified by heat, would perceive that it would be as much a miracle if smoke should not rise in a Chimney, (all hindrances to its ascent being removed,) as that water should refuse to run in a syphon, or to descend in a river."