110 Scientific Intelligence. 
_madder of two red coloring principles, viz.: alizarin and purpurin, 
and of yellow or orange substances which perform no important part 
“+ in the operation of the dyer. Alizarin, as prepared by a new process 
resembling that of Schunck, but for which we must refer to the origi- 
nal paper, presents itself in two different forms, viz., as hydrous and as 
anhydrous. The hydrated alizarin is obtained in scales which resemble 
eating it fuses and sublimes in orange-colored needles, a small portion 
at the same time undergoing decomposition. It is with difficulty moist- 
ened by cold water, but dissolves in boiling water with a deep yellow 
color. The smallest trace of alkali colors the solution red. ‘It is solu- 
ble in alcohol and ether ; the alcoholic solution is reddened by alkalies, 
the etherial on the contrary remains unchanged, as the red alkaline 
compound is. insoluble i in this medium Alkalies readily dissolve ali- 
liquid assumes a uniform violet tint. In alkaline anaes alizarin is 
soluble with a color resembling that of litmus, but without a blue re- 
flection. The authors refer the differences in color of sia solutions 
to the formation of different combinations of alizarin and alkali. Schunck 
Debus by C,, 9; the authors propose the formula C,,H,0¢; 
-and show that it accurately corresponds with the analytical results of 
both Schunck and Debus. The hydrate of alizarin is represented by 
C,,H,0,+4HO. The following table represents the constitution of 
the. principal compounds of alizarin 
Alizarin, oxyd of lead, #10. 8-0, )4-8Pb0 (Schunck.) 
Alizarin, pays of lead, 3(C, ato Lerat (Debus.) 
rin-lime, 2 Va) : 
Alia via, baryta, ats i 
* ss 2 (CP HO}, BBO aq. 
= ee 3 (C,,H,O,)+2Ba0 
By the action of different oxydizing agents upon alizarin, an acid is 
ebtained which was described by Schunck under the name of alizaric 
acid. Laurent and Gerhardt pointed out the resemblance between ee 
. . . . ] 
trecker have placed the identity of the two acids beyond @ 
doubt, es ‘epresent the conversion of alizaric rots phthalic acid by 
the a 
scalk acid Phthalic acid. Oxalic acid. 
tcc See ee 
“C,oH, 0,+2HO+0,—C,,H,O,+C,H,0,. 
* They further demonstrate that the chlo ro-naphthalic. acid of Lau- | 
rent is denial with chlorinated alizarin, as may be seen by the fol- 
lowi poets formu 
"Ali C, oHethee 
Chloro-raphthelic acid, Cuskke } : 
Cl §- 
