CHEMISTRY. 205 



apparently its doing them either good or harm. But, in the 

 turaco, the existence of the red coloring matter which belongs to 

 their normal plumage is dependent upon copper, which, obtained 

 in minute quantities with the food, is stored up in this strange 

 manner in the sj'stem of the bird. Thus, in the very same 

 featiier, partly red and partly black, copper was found in abun- 

 dance in the red parts, but none, or only the merest trace, in the 

 black. This red coloring matter is soluble in water ; and a pair 

 of birds, kejDt in captivity, lost their fine red color in the course 

 of a few days, in consequence of washing in the water which was 

 left them to drink ; except as to the loss of their beauty, how- 

 ever, it does not appear that the birds were the worse for it. — 

 Address of President Stokes before the British Association, 1869. 



ALIZARINE. 



M. Martin, taking advantage of Shiitzenberger's investigation 

 of madder, has invented a process for transforming orange- 

 madder, purpurine, pseudo-purpurine, and tantho-purpurine, 

 into alizarine. The several coloring matters are first dissolved in 

 concentrated sulphuric acid ; powdered zinc is then added, and 

 heat applied. When the reaction is completed, the mass is 

 diluted with water, and an abundant precipitate falls, which is the 

 required dye. This, after washing with water, is ready for use. 

 — Chem. News. 



ARTIFICIAL ALIZARINE. 



Messrs. Graebe and Liebermann, of Berlin, have discovered a 

 process for converting anthracene (paranaphtlialine), a constitu- 

 ent of gas-tar, into alizarine, the principal coloring matter of the 

 madder-plant. This conversion is accomplished by three succes- 

 sive operations : — 



First: the anthracene (Ch H.s) is transformed into oxanthracene, 

 or anthraquinone (Ch Hio) by heating one part of anthracene 

 with two parts of bichromate of potassium in the presence of 

 sulphuric acid or of crystallized acetic acid, or by the action of a 

 mixture of nitric and acetic acids. 



Second : the anthraquinone is heated with two equivalents of 

 bromine, and the product formed heated with alcoholic potash. 

 There results the compound Ch Re Br^, an(l from this, by the ox- 

 idizing action of nitric acid and bichromate of potassium, is 

 obtained the brominated compound Ch He Br2 O2, which is purified 

 by recrystallization. In this process chlorine can be-used instead 

 of bromine. 



Third : the brominated compound thus formed is heated with a 

 very concentrated solution of potash to from 180° to 2G0° C, until 

 the blue color which the mass assumes no longer increases in 

 intensity. The mass is then treated with an acid which precip- 

 itates the alizarine. — Bull. Soc. Ch., June, 18G9. 



MM. Graebe and Liebermann have recent!}^ stated that they 



18 



