PAPIN 121 



the steam engine in the year 1690 before it had been carried 

 out on an effective scale.^ He there also formulated the 

 idea of the high pressure machine, in which the pressure of 

 the steam in the cylinder drives the piston, and the produc- 

 tion of a vacuum by cooling is unnecessary, and he already 

 suggests the use of the machine for other purposes than 

 pumping water, for example, for driving ships by means of 

 paddle wheels. The piston rod was to be toothed, and act 

 upon a toothed wheel on the axis to be turned. A boiler 

 was not provided, the cylinder itself was to be alternately 

 heated and cooled. 



In the meantime Papin, in 1692, devoted himself to 

 building a submarine boat, and in 1698 he turned his atten- 

 tion to the centrifugal pump which he had invented. The 

 submarine boat was successful, after one or two failures, to 

 the satisfaction of the Landgrave. ^ The centrifugal pump, 

 a first application of centrifugal force as studied by Huygens, 

 worked well with air, when used to ventilate a mine shaft; 

 but for continuous pumping of water, the man-power used 

 at that time was not sufficient for the very rapid rotation 

 required. 



In the year 1698 Papin's circumstances improved, for the 

 Landgrave invited him, to his great joy, to be near him at 

 the Castle, in order to construct a machine to pump water 

 from the river Fulda to the top of a tower of the castle on 

 the river bank. Papin departed from the plans he had 

 published, and made use for this purpose of a special iron 

 boiler, the steam from which pressed either directly, or 

 through a piston floating loosely, upon the water, while 

 alternately, when the steam was cut off, fresh water flowed 

 into the space occupied by the steam. The machine was 

 unfortunately destroyed in November of the same year by 



^ Acta Eruditorum, August 1690. 



2 According to the drawings which have been preserved, Papin's 

 submarine may be described as an improved diving bell, closed at the 

 bottom. 



