ISOMERIDES OF ALIZARINE. 39 



colour not differing much from that of alizarine; and it dyes 

 mordants, while the other isomerides have no tinctorial 

 properties. 



7. Chrysazine, a body derived from hydrochrysammide, 

 and carefully examined by its discoverers, Liebermann and 

 Giesel. Acted on with strong nitric acid it yields chry- 

 samraic acid, the nitro- acid first obtained from aloes by one 

 of us many years ago. 



To these we have now to add : — 



8. Isoayithraflavine , a substance occurring in commercial 

 alizarine along with anthraflavine, which it closely resem- 

 bles. 



Chrysophanic acid, the crystalline colouring matter of 

 rhubarb, which at one time occupied a place in the list, has 

 been erased, since it has been shown by Liebermann that 

 it is ill reality a homologue of alizarine, having the formula 

 CijHjoO^, and is derived not from anthracene, but from a 

 methy lanthr acene . 



We propose in this paper to give an account of some 

 experiments on two of these isomerides, viz. anthraflavine 

 and isoanthraflavine. 



Anthraflavine. 



We have little to add to the description of this substance 

 given in the papers just referred to. Its melting-point is 

 above 330° C. It is less soluble in glacial acetic acid than in 

 alcohol. The analysis of a carefully purified specimen of 

 the substance yielded the following numbers : — 



0"24i2 grm. of substance gave 0"6i78 grm. CO^ and 

 o'o8o2 grm, HiO. 



Theory. Experiment. 



C,,t 168 70-00 69-85 



H^ 8 3'33 rh 



O, 



140 



