and Observations on Lac . 
209 
Properties of the colouring Extract of Lac. 
1. When dry, it is of a deep red colour, approaching to 
purplish crimson. 
2. Being put on a red-hot iron, it emits much smoke, with a 
smell somewhat resembling burned animal matter, and leaves 
a very bulky and porous coal. 
3. Water, when digested with it in a boiling heat, partially 
dissolves it; but the residuum was found to be absolutely in- 
soluble in water. 
4. Alcohol acts but slowly on it ; dnd, in a digesting heat, 
dissolves less than water. The colour of the solution is also not 
so beautiful; and a considerable part of the residuum left by 
alcohol was, when digested with water, found to be soluble, 
although this was not the case, when the residuum left by water 
was treated with alcohol. 
5. It is insoluble in sulphuric ether, excepting a very small 
portion of resin, which appeared to be accidentally mixed with 
it. 
6 . Sulphuric acid readily dissolves it, and forms a deep 
brownish-red solution, which, being diluted with water, and sa- 
turated with potash, soda, or ammonia, becomes changed to a 
deep reddish-purple. 
7. Muriatic acid dissolves only a part : the solution is of the 
colour of port wine, and, by the alkalis, is changed to a deep 
reddish-purple. 
8. Nitric acid speedily dissolves it: the solution is yellow, 
and rather turbid; but the red colour is not restored by the 
alkalis, for these only deepen the yellow colour. This nitric 
solution did not afford any trace of oxalic acid. 
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