JAMES WATT. 



direction. But it was impossible that they should have effected 

 any useful purpose by such methods of employing steam. 

 Steam depends so entirely for its existence in the state of 

 vapour upon the presence of a large quantity of heat, that it is 

 reduced to a mist or a fluid almost immediately on coming into 

 contact either with the atmosphere, or anything else which is 

 colder than itself; and in this condition its expansive force is 

 gone. The only way of employing steam with much effect, 

 therefore, is to make it act in a close vessel. The first known 

 writer who alludes to the prodigious energy which it exerts 

 when thus confined, is the French engineer Solomon de Caus, 

 who flourished in the beginning of the seventeenth century. 

 This ingenious person, who came to England in 1612, in the 

 train of the Elector Palatine, afterwards the son-in-law of James 

 I., and resided here for some years, published a folio volume 

 at Paris, in 1623, on moving forces; in which he states, that if 

 water be sufficiently heated in a close ball of copper, the air or 

 steam arising from it will at last burst the ball, with the noise 

 like the going off of a petard. In another place, he actually 

 describes a method of raising water, as he expresses it, by the 

 aid of fire, which consists in the insertion, in the containing 

 vessel, of a perpendicular tube, reaching nearly to its bottom, 

 through which, he says, all the water will rise, when sufficiently 

 heated. The agent here is the steam produced from part of 

 the water by the heat, which, acting by its expansive force upon 

 the rest of the water, forces it to make its escape in a jet 

 through the tube. The supply of the water is kept up through 

 a cock in the side of the vessel. Forty years after the publi- 

 cation of the work of De Caus appeared the Marquis of Wor- 

 cester's famous " Century of Inventions." Of the hundred new 

 discoveries here enumerated, the sixty-eighth is entitled " An 



