Page:A Letter on the Subject of the Cause (1797).djvu/15

 by ſuffering neither Water, or any other ſubſtance colder than the Steam, to enter or touch it during that Time.

, In Engines that are to be worked wholly or partially by Condenſation of Steam, the Steam is to be condenſed in Veſſels diſtinct from the Steam Veſſels or Cylinders, although occaſionally communicating with them; theſe Veſſels I call Condenſers; and whilſt the Engines are working, theſe Condenſers ought at leaſt to be kept as cold as the Air in the Neighbourhood of the Engines, by Application of Water or other cold Bodies.

, Whatever Air or other elaſtic Vapour is not condenſed by the Cold of the Condenſer, and may impede the working of the Engine, is to be drawn our of the Steam Veſſels or Condenſers by Means of Pumps wrought by the Engines themſelves, or otherwiſe.

, I intend in many Caſes to employ the expanſive Force of Steam to preſs on the Piſtons, or whatever may be uſed inſtead of them, in the ſame Manner as the Preſſure of the Atmoſphere is now employed in common Fire