THE GROWTH OF THE STEAM-ENGINE. 



2 3 



The description was not accompanied by a drawing, but the sketch 

 here given (Fig. (j), probably resembles his contrivance very closely. 

 Steam is generated in the boiler D, and thence is led into the ves- 

 sel A, already nearly filled with water. It drives the water in a jet 

 out through a pipe, 7^ or F'. The vessel A is then shut off from the 



Fig. 6. Worcester's Engine, a. d. 1650. Fig. 7. Wall of Raglan Castle. 



boiler and again filled "by suction" after the steam has condensed 

 through the pipe G, and the operation is repeated, the vessel B being 

 used alternately with A. 



The instruments of Porta and of De Caus were "steam fountains," 

 and were applied, if used at all, merely for ornamental uses. 



That of the Marquis of Worcester was used for the purpose of 

 elevating water for practical purposes at Vauxhall, near London. It 

 was still earlier used at the home of Worcester, Raglan Castle, where 

 the openings cut in the wall for its reception are still to be seen, as in 

 Fig. 7. 



14. The separate boiler, as here used, constitutes a very impor- 

 tant improvement upon the preceding forms of apparatus, although 

 the idea was original with Porta. 



The " water-commanding engine," as its inventor called it, was, 

 therefore, the first instance in the history of the steam-engine in which 

 the inventor is known to have " reduced his invention to practice." 



It is evident, however, that the invention, important as it was, 

 does not entitle the marquis to the honor claimed for him by many 

 authorities of being the inventor of the steam-engine. Somerset was 

 simply one of those whose works collectively make the steam-engine. 



Section II. The Period of Application of the Early Type of 

 Steam-Engine. JTorland, Savery, and Desaguliers. 14. The inven- 



