t 33 3 



VI. Experiments on the Yolk of Wool; with some Obser* 

 vations on the Washing and Bleaching of Wool. By 



M. VAUaUELIN*. 



Oeveral chemists have thought that the yolk of wool f is 

 a fat matter; others, finding that it dissolves in water, have 

 not adopted the same opinion. Chemical analysis can alone 

 decide this question, which is the object of the present 

 paper. 



1st, Water discharges much colour from wool ; and this 

 liquid acquires colour, odour, and taste. 



2d, The water with which wool has been washed is 

 milky, like an emulsion of gum-resin^ and it passes with 

 difficulty through paper. 



3d, It suffers to be deposited by rest a mixture of sand, 

 carbonate of lime, and several other foreign bodies : it 

 froths by agitation and heat like a solution of soap. 



4th, Water with which wool has been washed, when fil- 

 tered and evaporated furnishes a brown extract, thick like 

 syrup, of ail acrid, Salt, and bitter taste : in this state it still 

 retains the odoiir peculiar to it. 



5th, Alcohol applied to this extract dissolves a part which 

 communicates to it a reddish brown colour. If the alcohol 

 be separated by evaporation from this substance, it exhibits 

 the appearance of thick, viscous, and 'transparent honev. 



The other properties which appeared to me in this sub- 

 stance were as follow : 



1st, It dissolves readily in water, and the solution is im-» 

 mediately coagulated by acids, which separate from it grease 

 insoluble in water. This matter, when thus separated by 

 acids, collects itself very slowly^ and has a yellowish co- 

 lour. Acids, as will be seen hereafter, hold a great quan- 

 tity of it in solution, which gives them a reddish brown co-< 

 lour. By evaporation the greater part of this substance dis- 

 solves by acids, deposits itself under the form of black bi- 

 tumen; and salts, with a base of potash and of lime, are 

 obtained from it. These salts cannot be obtained in a state 

 of purity and whiteness till after several calcinations and so- 

 lutions, as the fat matter is v«ry adhesive. 



At the same time that the acids precipitate this fat mat^ 

 ter, they expel a certain quantity of acetous acid, very per* 



* From the Annates de Chimlc> No. 14.1* 

 f The French call it suint. 



No. 73k June 1804, . C ceptible 



