VINEGAR. “77 
upon repeated washings. The supernatant fluids are 
yellow. The alcoholic tincture evaporated, gives crys- 
talline scales, which seem black when viewed in a mass, 
and that a fatty substance renders brilliant; the liquor 
and the waters from the washings are of a yellow color. 
“Tincture of ether gives, likewise, by evaporation and 
an addition of water, a red precipitate, upon which floats 
a yellow liquor. 
“There are, then, in the hulls of the sorgho, two color- 
ing principles; the one red, slightly soluble in water, 
and soluble in alcohol, ether, the acids, and alkalies; 
the other, yellow, very soluble in water, and in the 
other solvents, which is not precipitable from its solu- 
tions like the red matter. 
“The red matter, which we may call purpurholcine, 
presents itself under the form of a reddish violet powder, 
so deep in color that it appears black; it has no smell; 
its taste (very weak) is a little bitter and astringent. 
Heated in a closed tube it does not volatilize, but gives 
empyreumatic vapors, which condense themselves into 
yellow oily drops. In presence of potashed lime it 
gives, under the influence of heat, alkaline vapors. It 
is then an azotized substance, and of which we will, 
further on, determine the atomic composition. The pur- 
purholeine is but little soluble in water, but dissolves 
readily in boiling water, in alcohol, cold and warm, and 
in ether, with a reddish color; sulphuric acid and chlo- 
rohydric acid dissolve it with an orange color. Potash, 
ammonia, lime water, and the water of baryta, communi- 
cate to it an intense color; alum, a red violet. It is not 
soluble in fixed oils; it can be prepared by several pro- 
Qe 
