ON THE CHEMICAL PROPERTIES OF SILK. 151 
In this vessel were placed six pound weight of 
yellow raw silk, over which he poured a composi- 
tion, consisting of a mixture of forty-eight pounds 
of aleohol (whose specific gravity was 0.867), with 
twelve ounces of muriatic acid in its purest state, 
(of the specific gravity of 1.114.) The vessel was 
then closed tightly up, and the contents left to 
digest, until the liquor became of a dusky brown 
colour; which operation usually required about 
twenty-four hours. This liquor was then drawn 
off by means of the glass tube, and spirit of wine 
was constantly poured into the vessel, while the 
tube was left unstopped, till the liquor passed off 
perfectly clear, and totally free from colour. The 
silk was then allowed to drain, until it ceased to 
drop. Spirit of wine and muriatie acid of the same 
proportions were again poured on it, and the silk 
allowed to continue immersed for forty-eight hours ; 
by which time it had parted with all its colouring 
matter, and had assumed a brilliant white. 
With respect to the exact time required for the 
immersion of the silk in the aleohol and muriatic 
acid, much will depend on the original colour of the 
silk, and also the temperature; and M. Baumé 
ascertained, that the silk wound from those cocoons 
which had not been previously baked, to destroy the 
aurelize, was much more easily bleached ; and that, 
on the second immersion, the liquor, when drawn 
off, was of a much paler hue, and so slightly was 
