The Pneumatics

...strated. Let us conceive the upper fluid, measured from the surface of the compressed body upon which the water is placed, to be a certain body equally heavy as the fluid and having the same figure as that upper fluid. Moreover, let us conceive this to be cast into the fluid in such a way that its lower surface corresponds to the compressed body and is as if it were that very thing; and let it be imposed in the same manner as the upper fluid. It is therefore evident that this body, once let down, neither projects at all above the fluid nor is submerged below the surface of the upper fluid. For it has been demonstrated by Archimedes, in the book on those bodies which are carried in water, that bodies of equal weight with the fluid, when let down into the fluid, neither project above the fluid nor sink. Therefore, it will not compress those things which lie beneath it. Furthermore, if the things compressing from above are removed, the body will remain in the same place. How then shall a body compress that which does not seek to descend to a lower place? In the same way, the fluid where the body was will not compress the things placed beneath; for as far as pertains to rest and motion, the afore-