THE CONQUEST OF NATURE 



model of this machine was produced before the Royal 

 Society in 1699. The transactions of the Society con- 

 tain the following: " June i4th, 1699, Mr. Savery en- 

 tertained the Royal Society with showing a small model 

 of his engine for raising water by help of fire, which he 

 set to work before them: the experiment succeeded ac- 

 cording to expectation, and to their satisfaction." 



The following very clear description of Savery's en- 

 gine is given in the introduction to Beckmann's History 

 of Inventions : 



"This engine, which was used for some time to a con- 

 siderable extent for raising water from mines, consisted 

 of a strong iron vessel shaped like an egg, with a tube 

 or pipe at the bottom, which descended to the place 

 from which the water was to be drawn, and another 

 at the top, which ascended to the place to which it was 

 to be elevated. This oval vessel was filled with steam 

 supplied from a boiler, by which the atmospheric air 

 was first blown out of it. When the air was thus expelled 

 and nothing but pure steam left in the vessel, the com- 

 munication with the boiler was cut off, and cold water 

 poured on the external surface. The steam within was 

 thus condensed and a vacuum produced, and the water 

 drawn up from below in the usual way by .suction. The 

 oval vessel was thus filled with water; a cock placed at 

 the bottom of the lower pipe was then closed, and steam 

 was introduced from the boiler into the oval vessel above 

 the surface of the water. This steam being of high 

 pressure, forced the water up the ascending tube, from 

 the top of which it was discharged, and the oval vessel 

 being thus refilled with steam, the vacuum was again 



[86] 



