A HISTORY OF SCIENCE 



new chemical in bleaching cloth soon supplanted 

 the old process of crofting that is, bleaching by 

 spreading the cloth upon the grass. But although 

 Scheele first pointed out the bleaching quality of his 

 newly discovered gas, it was the French savant, Ber- 

 thollet, who, acting upon Scheele's discovery that the 

 new gas would decolorize vegetables and flowers, was 

 led to suspect that this property might be turned 

 to account in destroying the color of cloth. In 1785 

 he read a paper before the Academy of Sciences of 

 Paris, in which he showed that bleaching by chlorine 

 was entirely satisfactory, the color but not the sub- 

 stance of the cloth being affected. He had experi- 

 mented previously and found that the chlorine gas 

 was soluble in water and could thus be made practically 

 available for bleaching purposes. In 1786 James Watt 

 examined specimens of the bleached cloth made by 

 Berthollet, and upon his return to England first in- 

 stituted the process of practical bleaching. His proc- 

 ess, however, was not entirely satisfactory, and, after 

 undergoing various modifications and improvements, it 

 was finally made thoroughly practicable by Mr. Ten- 

 nant, who hit upon a compound of chlorine and lime 

 the chloride of lime which was a comparatively 

 cheap chemical product, and answered the purpose 

 better even than chlorine itself. 



To appreciate how momentous this discovery was to 

 cloth manufacturers, it should be remembered that the 

 old process of bleaching consumed an entire summer 

 for the whitening of a single piece of linen ; the new 

 process reduced the period to a few hours. To be sure, 

 lime had been used with fair success previous to Ten- 



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