92 The cmsequences of the

of a column of mercury twenty eight incheshigh, and whose base is the same with theportion of the air we take (g) : and this whenthe air is not compressed, but in the famestate with the outward atmosphere. NoWthe use that I would make of this is, to sheWthat, abstracting from the reasoning in N°14, 15 and 16. sect. i. this is another con-tradictory appearance, unless we call in animmaterial Mover, that a thin film of air(for the whole force must be lodged in that,by what was said just now) of a foot square,v. g. whose natural resistance doth not a-mount to one grain, should yet resist, andsupport a weight, that might be a load sotan elephant. The weight of a whole cubi cfoot of air is but about 506 grains, and th 6weight of such a film would scarce be a 5 o 6thpart of that (h ); and the pillar of water, os

(g) tVolsius, Element. A'erometrica , tbeor. 1, Elatfaeris inferioris aquatur ponderi totiussuperioris ipji incutshentis. And cor. 1. Quoniam pondus aeris superioris i >1 'feriori incumbentis aquatur ponderi columnœ aquea , cuj^eadem cum volumina aeris bass, fed altitudo triginta uttiu 5pedum , vel etiam columna mercuriali, cujus altitudo $digitorum ; elater aeris inferioris eidem columna aquea , ^mercuriali equatur.

(h) Ibid. probl. 5. Invenire pondus unius pedis cub >cl

aeri ; and the scholium of it. at*

4