Chap. 3.] New An of Bleaching. 1 $ 



turnfole. The ancient prejudices concerning the dew 

 of the month of May, a feafon when the tranfpiration 

 of plants is moft abundant, he conceives to have ori- 

 ginated in a fimilar obfervation. 



Attributing, therefore, in his own mind the com- 

 mqn effect of whitening linen' in bleach-yards to the 

 action- of oxygen, he was led to imitate that procefs. 

 by applying leys, and the oxygenated muriatic acid 

 alternately, and by thefe means was enabled to make 

 linen, &c. permanently white, by a very quick and 

 eafy prccefs. Obierving further that it was the prac- 

 tice in common bleaching, to make the linen, &c. in 

 the finiming, pafs through four milk, or a very weak 

 mixture of the vitriolic acid with water; he alfo tried 

 the paffing of the cloth through a very dilute folution 

 of the vitriolic acid, and obferved that it was confe- 

 quently rendered of a clearer white. 



The oxygenated acid may be employed either in 

 the aerial fjrm, or diluted with waters and the latter 

 appears to be the moft convenient mode of applying 

 it. The effect feems to refult entirely from the ac- 

 tion of the oxygen which the acid parts with to the 

 cloth, and which has a power of deftroying vegetable 

 colours. Perhaps the fading of dyed Ruffs on being 

 expofed to the action of the light and air may be ac- 

 counted for on the fame principles. The acid which 

 M. Berthollet employed in bleaching he found had 

 parted with all its fuperabundant oxygen to the cloth, 

 and was reduced to the ftate of the common muriatic 

 acid. The foap-leys feem to.act in two ways; by neu- 

 tralizing any of the fuperfiuous acid which might be 

 imbibed, it faves the cloth from being corroded ; and 

 it alfo prevents the fuffocating fumes of the oxyge- 

 nated acid from being offenfive or ^injurious. Poffibly 

 the detergent quality of the leys may have a further 



