Chapter 25

“About a foot below one of the side windows was a circular opening, eight inches in diameter, and fitted with a brass rim adapted in its inner edge to the windings of a screw. In this rim was screwed the large tube of the condenser, the body of the machine being, of course, within the chamber of gum-elastic. Through this tube a quantity of the rare atmosphere circumjacent being drawn by means of a vacuum created in the body of the machine, was thence discharged, in a state …