244 M, Arago's Biographical Memoir of James Watt. 



that of Denis Papin. It is to Papin that Finance owes the 

 honourable rank she may claim in the history of the steam- 

 engine. The high satisfaction which his success inspires is not 

 however without its alloy. The claims of our counti'yman are 

 to be found only in foreign archives ; he published his greatest 

 works on the other side of the Rhine ; his liberty was threat- 

 ened by the Revocation of the Edict of Nantes ; and it was in 

 melancholy exile that he for a time enjoyed that blessing of 

 which studious men are the most jealous, namely, tranquillity. 

 Let us throw a veil upon these deplorable results of our civil 

 discords, — let us fox'get that fanaticism attacked the religious 

 opinions of the philosopher of Blois, and let us turn again to 

 mechanics, in respect of which, at least, the orthodoxy of Papin 

 has never been disputed. 



There are in every machine two things to be considered : 

 These are, first the moving power ; and secondly the arrange- 

 ment, more or less complicated, of the frame and moveableparts, 

 by the aid of which the moving power transmits its action to the 

 resistance. At the stage of perfection which mechanical science 

 has now reached, the success of a machine intended to produce 

 great efi"ects, depends chiefly upon the nature of the moving 

 power, on the manner of its application, and on the manage- 

 ment of its force. Now, we find that it was to the production 

 of an economical moving power, capable of effecting the un- 

 ceasing and powerful strokes of the piston of a large cylinder, 

 that Papin consecrated his life. The procuring afterwards 

 from the strokes of the piston, the power requisite to turn the 

 stones of a flom*-mill, the rolls of a flatting-mill, the paddles 

 of a steam-boat, the spindles of a cotton-mill ; or to uplift the 

 massy hammer, which vdth oft-repeated stroke thunders upon 

 the enormous masses of red-hot iron just taken from the 

 blast-furnace ; to cut with great shears thick metal bars, as 

 easily as you divide a ribband wdth your scissors ; these, I 

 repeat, are problems of a very secondary order, and which 

 would not embarrass the most common engineer. Hence, 

 therefore, we may occupy ourselves exclxisively with the me- 

 thods by means of which Papin proposed to produce his oscilla- 

 tory movement. 



