] 03 
As it might be interesting to many of the members to 
have an outline of one of the methods employed, he would 
therefore describe a process detailed in the specification of 
Messrs. Caro, Graebe, and Liebermann. One part of anthra- 
cene is heated with four of sulphuric acid, of specific gravity 
1-845, for three or four hours, to a temperature of 212° F., 
and then for about an hour at 300°. The mixture is 
allowed to cool, and to it is added water equal to three times 
the weight of the anthracene employed, and manganese equal 
to four times that weight. The whole is boiled for three 
hours and milk of lime added, which gives rise to a deposit 
consisting of the excess of lime and manganese used and 
protoxide of manganese, while there remains in solution a 
double sulphate of anthraquinone and lime. This solution 
is now acted on by carbonate of soda in . slight excess, car- 
bonate of lime separates, and the salt of soda thus produced 
is evaporated to dryness. This solid mass is then mixed 
with tAvo to three parts of caustic potash or soda and a 
small quantity of water, and the whole heated under pres- 
sure in suitable vessels at a temperature of 350° to 500° F. 
for one hour, Avhen the anthraquinone is further oxi- 
dized and converted into alizarine. The alkaline mass on 
cooling is dissolved in water and sulphuric or acetic acid 
added in slight excess, Avhen an orange-yellow fiocculent 
substance precipitates, which, when properly washed and 
dried, is artificial alizarine. 
If this process can be carried out on a practical scale (and 
there is no doubt that it will be under the direction of such 
clever chemists as Messrs. Perkin, Caro, and others), Ave may 
then fairly consider the production of artificial alizarine aS 
having reached the sphere of commercial application; though 
I may add from personal experience that some time must 
elapse before it can be manufactured in quantities suffi- 
cient to affect the present applications of madder, garancine, 
Schunckts artificial alizarine, &c., &c. 
