124 MR. E. SCHUNCK ON A COLOURING MATTER 
lected on a filter and washed with cold water, are dissolved 
in boiling alcohol. The alcoholic solution is filtered from 
a small quantity of insoluble matter, and then distilled 
until the greatest part of the spirit has passed over. The 
dark yellow liquid left in the retort is then poured into a 
dish, and allowed to stand for some time, when it deposits 
the pure colouring matter as a mass of crystalline needles 
of a pale primrose-yellow colour. These are collected on 
a filter, washed with a little cold alcohol, and allowed to 
dry spontaneously. Its properties are as follows : — 
It is perfectly tasteless, and its solutions are neutral to 
test paper. When heated on platinum foil it melts to a 
brown transparent liquid, and then burns with a yellow 
flame, leaving much charcoal, which, on being heated, 
burns slowly away without leaving any ash. When heated 
in a tube it melts, gives off fumes having a strong empyreu- 
matic smell, and yields a yeliow oily sublimate, in which 
nothing crystalline is formed even after several days. 
It is hardly soluble in cold water, and only sparingly 
soluble in boiling water. The boiling watery solution 
deposits it on cooling in yellow silky needles, which, when 
dry, form a compact silky mass. It is more easily soluble 
in boiling alcohol than in water. It does not separate from 
the alcoholic solution on cooling, but is left on evaporation 
in star-shaped masses of a darker yellow colour than the 
needles obtained from the watery solution. Strong muriatic 
acid changes its colour to a deep yellow without decompos- 
ing it. When concentrated sulphuric acid is brought into 
contact with it, the acid acquires at first a greenish colour, 
and then dissolves it entirely, forming a deep yellow solu- 
tion, from which the greatest part of the colouring matter 
is precipitated by water in yellow flocks. If, however, the 
solution in acid be heated it becomes black and gives off 
sulphurous acid in abundance, the colouring matter being 
