76 MR. SCHUNCK ON RUBIAN AND ITS PRODUCTS OF DECOMPOSITION. 
similar to rabianine and rubiadine, to which I shall give the name of Rubiagine ; and, 
6thly, a peculiar fatty substance which I shall denominate Rubiadipine. These sub- 
stances are separated in the following manner. The mixture is treated with boiling 
alcohol. The alcohol, which assumes a dark reddish-yellow colour, is filtered, and 
the substance on the filter is treated again with boiling alcohol, until the latter 
acquires thereby only a light yellow colour. The substance left on the filter consists 
of the ferment, which has undergone no apparent change either in quantity or proper- 
ties. To the alcoholic liquid there is now added acetate of alumina, which produces 
a dull yellowish-red precipitate. This precipitate, which consists of alizarine, veran- 
tine and rubiafine in combination with alumina, is separated by filtration and decom- 
posed with boiling muriatic acid, which leaves undissolved a quantity of orange- 
coloured flocks. The liquid filtered from the alumina precipitate has a dark brown- 
ish-red colour. By adding to it sulphuric acid and a large quantity of water, the 
substances contained in it are precipitated in the shape of a yellow powder. This 
powder yields nothing to boiling water, which proves the absence of rubianine among 
the products of decomposition. After being separated by filtration, and washed with 
water to remove the acid and aluminous salts, it is again dissolved in boiling alcohol, 
and to the boiling solution there is added an excess of sugar of lead, which causes a 
dark purple precipitate, the liquid becoming dark yellow. The latter is filtered 
boiling hot and then mixed with a large quantity of water, which produces a dull 
orange-coloured precipitate, consisting of rubiagine and rubiadipine in combination 
with oxide of lead. This precipitate is boiled with sulphuric acid, which turns^ it 
yellow; and after the excess of acid has been removed with water, it is treated with 
boiling alcohol, which leaves undissolved a quantity of sulphate of lead, and acquires 
a yellow colour. The alcohol on evaporation leaves a residue consisting of rubiagine 
and rubiadipine. This residue is treated with cold alcohol, in which the rubiadipine 
dissolves easily, and is obtained on again evaporating as a dark brown, soft, fatty 
mass. The rubiagine left undissolved is treated with a small quantity of warm 
alcohol, which removes an additional quantity of rubiadipine, together with a portion 
of the substance itself, and on redissolving it in boiling alcohol and^ evaporating 
spontaneously, it appears in the form of a lemon-yellow mass consisting of sinall 
crystalline grains. The dark purple precipitate produced by sugar of lead consists 
of oxide of lead in combination with rubiretine, alizarine, verantine and rubiafine. 
It is treated with boiling muriatic acid, which dissolves the oxide of lead. The yellow 
flocks left by the muriatic acid are, after washing with water, treated with cold 
alcohol which leaves a part undissolved, and on evaporation gives a residue consisting 
for the most part of rubiretine. By treating this residue again with cold alcohol, an 
additional quantity of substance is left undissolved, and the rubiretine is now obtained 
in a state of greater purity. Its appearance and properties are the same as when 
obtained by the action of acids or alkalies on rubian. The substance left undissolved 
by the cold alcohol is added to the orange-coloured flocks proceeding from the 
