138 
REPORT - 1847 . 
dissolved by the alcohol. The boiling alcohol, after being filtered, dfposia 
on cooling rubiacin in small shining yellow crystals, which must be purififd 
by recrystallization. The fluid has a yellowish-red colour. Onevaporatra 
it gives a quantity of an easily fusible dark reddish-brown fat, which bv ^ 
peated fusion in boiling water and agitation with tlu* fluid while in a meltd 
state, may be separated from the rubiucin which adheres to if. The rububc 
acid which is left by tho boiling alcohol is treated w ith a weak boiling mIv 
tion of carbonate of pota.di, in which it dissolve# w’ith a dark brown cobit 
The solution alter cooling and standing some time depodts a moss of brid- 
red needle-shaped crystals of rubiacatc of ptitash, which are eadly purified bf 
recrystallization. By dissolving this salt in boiiitjg water and addinj; wr 
strong acid, rubiacic acid in a state of purity is precipitated as a bright lemov 
yellow powder. The dark solution from wdiich the rubiacateof pota«hlm 
crj-stallized contains a quantity of the brown fat dissolved in the potash. 
The brown substance left undinsolved by the perchloride or pemitrat««f 
iron is, as I stated above, a compound of one of the two fats with 
iron. On being treated with muriatic acid the oxide of iron is dissuhd, 
leaving behind the fat, which, after being wiishcd with water, is dissolrtc 
in boiling alcohol. Worn this it is deposited on couliog as a light broffi 
powder. 
1 luentioiKuI above tliat the residue which is Ii;ft on treating the bro*^ 
precipitate with boiling alcohol, consists principally of poetic acid, h* 
treated with boiling water until nothing more is dissolved. The 
which has a light brown colour, and is aoniewliat mucilaginous, giveiabrovt. 
transparent substance, which easily separates in scales from the sides and 
bottom ot the vessel. After treating the residue witli water until nothini 
more is dissolved, there still remains a dark brown substance undiswlveJ. 
^ to bn a compound of some of the preceding siibstauce? wta 
oxide of iron, as it leave# a considerable quantilv of ash, consisting of 
oxide of iron, on being burnt. ' 
To the aquoous extractor madder, in which the brown precipitate bi 
been produced by oxalic acid, I added chalk until all the excess of acid «« 
satumted, and after Hltratioii I evaporated it. It left a dark brown JVWP' 
which may be separated by means of alcohol into two substances. TW 
which IS dissolved seems to be grape-sugar, and tliat which is left » 
a species ot oxtraetivo matter, which agrees in its uroperties with 
Kuhlmann. It iuu a brown colour. ^ During evajwati'i' la 
tractive substonce or apothegum.like “l 
n 7 , ““uie «uipouric or muriatic acid, t ^ 
such » rl M moutioH that it is probably thU body which 
the red ™ of .oadder-dyeieg, re.dtn», 
the red aod purple bro^u, . , 
some “ more‘detailed account of the propf^ti 
‘"ethod* of obtaining which I havejuatd^ 
rill i,7thc n'r "tate tliat the substance which I cailed.*^^ 
the RritiV i’"'" at the Southampton mectiB? 
s anrJ I now call rubiacin. I am of opinion tiiat th^oj 
standee discovered by Hobiquet. and called by him alizarin, does not agree 
ht Sunr ^ rubiaci/; but after carefully comp^^ 
sionX 1 1 have come to the co^‘^ 
ticul wUh his. ^ applied the name of alizarin w id 
