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XVIII. An Effay on Bleaching; with theDefcriptionofa 

 7iew Method of Bleaching by Steam according to the Pro- 

 cefs of C. Chaptal; arid on its Application to the Arts, 

 By R. O'Reilly, of the Academy of Bologna, Member 

 of the Lycaum of the Arts, &c. 



JL HE art of bleaching is one of thofe connected with 

 the firft ideas of civilization. The theory on which it is 

 founded was entirely unknown to the antients ; but the 

 Egyptians were acquainted with the deterfive quality of fome 

 kinds of clay, and the effect produced by the atmofphere, 

 moifture, and light, on the (luffs expofed to their acYion. 



Health and cleanlinefs rendered it neceffary to devife 

 quicker means than thefe; and the property of foap and leys 

 of allies were therefore foon difcovered. 



In the prefent age, the arts, following fcience with clofe 

 fteps, have taken advantage of proeeffes and deterfive men- 

 ftrua, the exigence of which was before unknown : thefe 

 difcoveries have fucceeded each other with fueh rapidity, that 

 the laft fix years have effeded a complete revolution in the 

 art of bleaching. 



This art divides itfelf very naturally into two quite diftinft 

 branches, which we (hall avoid confounding. One of them 

 comprehends the bleaching of animal fubftanees ; the other, 

 that of vegetable matters. We (hall treat of thefe fubje&s 

 feparately, as well as of the different menrtrua' and deterlive 

 fubftanees generally employed. 



Bleaching of Animal Subficnces. 



The fubftanees produced by the animal kingdom, which 

 are more particularly employed as Veftments, differ effentially 

 from thofe of the vegetable kingdom. It is on a knowledge 

 of the mod ftriking traits, which form the line of demarca- 

 tion between the two kingdoms, that the art of bleaching is 

 founded. 



Vegetables ferve as nourimment to the animals and infects 

 the fpoils of which we employ. Animalized by their organs 

 jthey acquire other properties. Azote, in particular, feems 

 to be their moft diftinguifhing character: it is fearcely found 

 in vegetable fubftanees. To this principle we may ia\d the 

 exiftence of fulphur and phefphorus, which form ib many 



Vol. X. G Igurces 



Phil. Mag, No. 38. 

 July 1 801. 



