100 



DISSERTATION SECOND. 



[part I. 



pari it to bodies by any means so simple and easy, as by 

 the common process of immersing them in a liquid of a 

 given colour. 



In some instances, however, the theories of chemistry 

 have led to improvements of art very conformable to the 

 anticipations of the Novum, Organum. A remarkable in- 

 stance of this occurs in the process for bleaching, invented 

 by Berthollet. It had been for some time known, that the 

 combination of the chemical principle of oxygen with the 

 colouring matter in bodies, destroyed, or discharged, the 

 colour; and that, in the common process of bleaching, it 

 was chiefly by the union of the oxygen of the air with the 

 colouring matter in the cloth that this effect was produced. 

 The excellent chemist just named conceived, therefore, 

 that if the oxygen could be presented to the cloth in a 

 dense state, and, at the same time, feebly combined with 

 any other body, it might unite itself to the colouring 

 matter so readily, that the process of bleaching would by 

 that means be greatly accelerated. His skill in chemistry 

 suggested to him a way in which this might easily be done, 

 by immersing the cloth in a liquid containing much oxygen 

 in a loose state, or one in which it was slightly combined 

 with other substances, and the effect followed so exactly, 

 that he was able to perform in a few hours what required 

 weeks, and even months, according to the common process. 

 This improvement, therefore, was a real gift from the 

 sciences to the arts ; and came nearly, though not alto- 

 gether, up to the ideas of Bacon. I suspect not altogether, 

 because the manner in which oxygen destroys the colour 

 of bodies, or alters the structure of their surfaces, remains 

 quite unknown. 



It was natural, however, that Bacon, who studied these 

 ■subjects theoretically, and saw nowhere any practical re- 

 sult in which he could confide, should listen to the inspira- 



