236 DR. EDWARD SCHUNCK ON 



XXIX. On Methyl-alizarine and Ethyl-alizarine. 

 By Edward Schunck, Ph.D., F.R.S. 



Bead March 18th, 1873. 



In a paper read before this Society some time ago I gave 

 an account of a yellow colouring-matter accompanying 

 artificial alizarine, to which I gave the name of anthra- 

 flavic acid. 



My analyses of the acid and of its barium and silver 

 salts led to the formula C I5 H io 4 for the acid; and I 

 was therefore inclined to view it as a body homologous 

 with alizarine, or alizarine in which H is replaced by CH r 

 I supposed it to be derived from a hydrocarbon higher in 

 the series than anthracene, contained in the ordinary 

 anthracene of commerce and having the formula C I5 H ia , 

 a body which is supposed by some chemists really to exist, 

 and which would stand in the same relation to anthracene 

 as toluol does to benzol. It was necessary to adopt some 

 such hypothesis, since, as Graebe and Liebermann remark 

 in referring to my experiments, a compound obtained from 

 anthraquinone by the same process as that yielding aliza- 

 rine cannot possibly contain 15 atoms of carbon 



The examination of anthraflavic acid was subsequently 

 undertaken by Mr. Perkin*, whose analyses, of the care- 

 fully purified substance led to the conclusion that it is 

 isomeric with alizarine. I do not wish to dispute the 

 accuracy of this view of its composition, since a trifling 

 admixture of some impurity, such as anthraquinone, might 

 easily have given rise to the excess of carbon found in my 

 analyses — though I may state that a specimen of the sub- 

 stance prepared, not from commercial alizarine itself but 



* Chem. Soc. Journ. vol. xxiv. p. 1109. 



