CONSTITUENTS OF COTTON-FIBRE. 99 



commerce '^ Middling Orleans/' It was treated in the 

 same manner as the other two lots, and yielded a preci- 

 pitate of exactly the same appearance as that from East- 

 Indian cotton, and amounting, when diy, to 0-48 per cent, 

 of the weight of the yarn employed. 



The precipitate, in all three cases, consisted for the most 

 part of organic matter. In addition to the matter ex- 

 tracted from the cotton by the alkali, it contained a small 

 quantity of cotton filaments, which had been detached from 

 the yarn during the process of boiling. When incinerated, 

 it left from 2*3 to 6*9 per cent, of a light-yellow non-alkaline 

 ash. This ash consisted chiefly of oxide of iron, alumina, 

 and silicate of alumina, the remainder being sulphate of 

 lime and sulphate of soda. 



The three lots of precipitate obtained were treated sepa- 

 rately ; but as the products which they yielded were essen- 

 tially the same, the same process of treatment was applied 

 to all. This process was as follows : — 



The precipitate was in the first instance treated, while 

 still moist, with boiling alcohol, and the boiling liquid was 

 filtered through a large tin funnel, surrounded by hot 

 water. The residue on the filter was treated again with 

 boiling alcohol, and the process was repeated until nothing 

 more was dissolved. More than half of the precipitate 

 remained undissolved. The undissolved residue was much 

 paler than the original precipitate, the colouring-material 

 of which had, for the most part, passed into solution. The 

 alcoholic liquid, which was of a dark-brown colour, de- 

 posited, on cooling, a quantity of dirty white flocks, which 

 were filtered off", washed with alcohol, and then redissolved 

 in boiling alcohol. On adding to this solution a little acetate 

 of lead, a dark-brown precipitate was produced, consisting of 

 a compound of colouring- matter with lead ; and the liquid, 

 after being filtered as before through a hot-water funnel, 

 and allowed to cool, deposited a quantity of nearly white 



H 2 



