26 WATT. 



small orifice or tube with great force, could, they con- 

 ceived, blow a fire or even turn the vanes of a mill. No 

 use, however, seems ever to have been made of this phi- 

 losophical toy, nor does any attention appear to have 

 been paid to steam, as an agent, until 1615, when Sa- 

 lomon de Caus, a French engineer, published a work 

 on ' Moving Forces,' in which he describes a method 

 of raising water by partially heating it, that is, convert- 

 ing a portion of it into steam, and, by its expansive 

 force, driving the rest of the fluid through the tube con- 

 nected with the reservoir or chamber.* In 1663 the 

 Marquis of Worcester (known in our political his- 

 tory as Earl of Glamorgan, and as having been em- 

 ployed by Charles I. in 1646 to negotiate with the 

 Irish Catholics) published his ' Century of the Names 

 and Scantlings of Inventions,' of which Mr. Hume, in 

 his 'History' (vol. vii., note o), has been pleased to 

 say that it is " a ridiculous compound of lies, chimeras, 

 and impossibilities, showing what might be expected 

 from such a man." The better opinion seems to be, 

 that the historian had never read the book he thus de- 

 scribes ; but being anxious to relieve Charles I., from 

 the blame of his Ambassador's negotiation, which 

 proved the source of much outcry against the King, he 

 states the low opinion which the latter entertained of 

 Worcester's judgment as a proof that he never would 

 authorize him to act in so delicate a matter as religious 

 concessions without the privity of the Lord-Lieutenant, 

 and he is very ready to strengthen this view by show- 

 ing that the opinion was well founded. Be this, how- 

 ever, as it may, the ignorance and error is all on Hume's 



* M. Arago is not entitled to complain of English writers for having 

 " aimed at expunging every French name from this important chapter in 

 the history of science." He says they at once gave up Lord Worcester's 

 claims on discovering that Salomon de Caus had preceded him. Now, 

 both Mr. Farey and Mr. Stuart have done ample justice to Caus in then- 

 works on the steam engine. As for Lord Worcester, Mr. Stuart (whose 

 history is far from accurate on this point) has both attacked and defended 

 his claims in his several works. 



