ON DYEING REDS ON COTTON. 2^3 



The theory just laid down is supported by experiment. Sheep's dung 

 Having macerated fresh sheep's dung for four or five days ^j!!^* 16 *" 

 in a lixivium of soda at 4°, I filtered, and obtained a reddish 

 brown liquid. On separating the alkali by very dilute yielded a pre- 

 8ulphuric acid, a copious, li^ht precipitate was formed, cl P ltate > 

 which subsided to the bottom of the vessel, after having 

 for some time occupied its whole capacity. 



To remove all doubt respecting the nature of this pre- consisting of 

 cipitate, I collected it on a filter, washed it well with cold 

 water, and then boiled it in a phial of pure water for 

 near an hour. I then decanted off the liquid, which was 

 of a reddish yellow, and poured into it a solution of tannin. 

 This formed a precipitate, announcing sufficiently the pre- gelatine 

 sence of gelatine. 



The albumen, coagulated by the action of the heat, re- and albumen. 

 mained at the bottom of the phial in the form of little soft 

 and spongy grumes: and to judge by the quantity of mat- 

 ter insoluble in water, though it was renewed three or four 

 times, albumen abounds much more than gelatine in The latter most 

 sheep's dung. I do not think it would be far from the abundant. 

 truth to say, that the albumen is to the gelatine at least 

 as three to one. Particular circumstances prevented my 

 carrying the investigation to such a degree of accuracy, as I 

 could have wished for my own satisfaction. 



To establish a complete conviction on this subject, I An alkaline 

 shall add, that I tried an alkaline solution of whites of b umen answer- 

 eggs, or albumen, instead of the sheep's dung bath ; and ed equally 

 that it succeeded completely in the preparation for both we ' 

 kinds of dyeing: all the colours were rendered much more 

 permanent, than where natural or artificial sheep's dung 

 baths were omitted. 



This observation, founded on theory and experience, 

 completely refutes the assertion of Le Pileur d'Apligny, 

 that the dung and intestinal liquor of the sheep are of no 

 use in fixing colours. 



2C 



