2 2 HER OES OF INVENTION AND DISCO VER Y. 



admirable and most forcible way to drive up water by fire." 

 As far as may be judged from the vague description which the 

 Marquis gives us of his apparatus, it appears to have been 

 constructed upon the same principle with that formerly pro- 

 posed by De Cans ; but his account of the effect produced is 

 considerably more precise than what we find in the work of his 

 predecessor. "I have seen the water run," says he, "like a 

 constant fountain-stream forty feet high ; one vessel of water 

 rarefied by fire, driveth up forty of cold water." This language 

 would imply that the Marquis had actually reduced his idea to 

 practice ; and if, as he seems to intimate, he made use of a 

 cannon for his boiler, the experiment was probably upon a 

 considerable scale. It is with some justice, therefore, that not- 

 withstanding the earlier announcements in the work of the 

 French engineer, he is generally regarded as the first person 

 who really constructed a steam-engine. 



About twenty years after this, namely in the year 1683, 

 another of our countrymen, Sir Samuel Morland, appears to 

 have presented a work to the French King, containing, among 

 other projects, a method of employing steam as a mechanic 

 power, which he expressly says he had himself invented the 

 preceding year. The manuscript of this work is now in the 

 British Museum; but it is remarkable that when the work, 

 which is in French, was afterwards published by its author at 

 Paris, in 1C85, the passage about the steam-engine was omitted. 

 Sir Samuel Morland's invention, as we find it described in his 

 manuscript treatise, appears to have been merely a repetition 

 of those of his predecessors, De Caus and the Marquis of 

 Worcester ; but his statement is curious as being the first in 

 which the immense difference between the space occupied by 

 water in its natural state and that which it occupies in the 



