86 
fairly concluded that the thickness of layers of stalagmite 
cannot he used as an argument in support of the remote age 
of the strata below. At the rate of a quarter of an inch per 
annum 20 feet of stalagmite might be formed in 1000 years. 
“On Methyl-alizarine and Ethyl-alizarine/’ by Edward 
Schunck, Ph.D., F.RS. 
In a paper which I had the honour of reading 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 anthraflavic acid. Though the sub- 
stance was at the time new to me and apparently to others 
also, it is quite possible it may have been previously observed 
by those working with artificial alizarine, since the crude 
product is probably hardly ever quite free from it, and its 
presence would not be likely to escape the notice of any one 
endeavouring to prepare pure alizarine from the manufactu- 
red article. 
My analyses of the acid and of its barium and silver salts 
led to the formula C15H10O4 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 3 . I supposed it to 
be derived from a hydrocarbon higher in the series than 
anthracene (C 16 H 12 ?) contained in the ordinary anthra- 
cene of commerce, a body which is supposed by some che- 
mists 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 alizarine cannot possibly contain 15 atoms 
of carbon. The conversion of the acid into alizarine by 
the action of fusing caustic potash would however admit of 
explanation in accordance with my view, since the methyl 
# Proceedings Lit. and Phil, Soc., Session 1870-71. 
