Page:A Letter on the Subject of the Cause (1797).djvu/52

 or that both theſe fluids enter the vacuum at the ſame time, which is the caſe in theſe Engines, what will be the iſſue? Certainly as follows, for the foundation of nature mutt be reverſed before it can be otherwiſe. Whatever is the quantity of water, it will by its own gravity preſſing on that water already in the pipe, deſtroy the equilibrium before maintained there with the outer air; and to reſtore it, jut as much water will be diſcharged through the valve at the bottom of the eduction pipe, as is equal in gravity, even to a ſingle drop of the quantity which has as above entered the vacuum or condenſer. But can the air or uncondenſed vapour be carried off through this eduction pipe by its own gravity? Common ſenſe anſwers in the negative; Dame Nature confirms it; and the ſwelling vapour ſhews a determination to be uppermoſt, in ſpite of James Watt, or Mr. Gitty; and will, before compelled to leave its habitation, drive into the open air every drop of water which ſerved to confine it. This, my Lord, I am perſuaded will be quite ſufficient to ſhew the impoſſibility of cleanſing the condenſer or vacuum in this way. For the air or vapour muſt here expand itſelf with a force more than equal to the atmoſpheric preſſure,