THE PERIOD OF APPLICATION. 53
The sketch is that given by the inventor in his memoir.
It consists (Fig. 18) of a steam-boiler, a, from which steam is
led through the cock, e, to the working cylinder, n. The water
beneath the floating-piston, A, which latter serves simply as
a cushion to protect the steam from sudden condensation or
contact with the water, is forced into the vessel r r, which
is a large air-chamber, and which serves to render the out-
flow of water comparatively uniform, and the discharge oc-
curs by means of the pipe g, from which the water rises to
the desired height. A fresh supply of water is introduced
through the funnel k, after condensation of the steam in n,
and the operation of expulsion is repeated.
FIG. 18. Papin's Engine and Water-Wheel, a. D. 1707,
This machine is evidently a retrogression, and Papin, after having earned the honor of having invented the first steam-engine of the typical form which has since become so universally applied, forfeited that credit by his evident ignorance of its superiority over existing devices, and by attempting unsuccessfully to perfect the inferior device of another inventor.
Subsequently, Papin made an attempt to apply the steam engine to the propulsion of vessels, the account of which will be given in the chapter on Steam-Navigation. Again disappointed, Papin once more visited England,
