r 



Dr. Scbunck on Rubian dhd its Products of Decomposition, 28l' 



off and washed witli water, dissolves again in boiling alcohol, 

 with the exception of a little brown flocculent matter. The al- 

 coholic solution, on evaporation, leaves a yellow uncrystalline 

 substance resembling impure rubiadine, which contains no chlo- 

 rine, gives when heated a sublimate like that from rubiadine, and 

 forms with baryta a compound which crystallizes in dark reddish- 

 brown needles. I obtained so small a quantity of this substance 

 that I was unable to arrive at any positive conclusion as to 

 whether it is identical with rubiadine or not. The residue left 

 on evaporation of the alcoholic solution was analysed without 

 any attempt being made to purify it, when it was found to l^^ve. 

 a composition nearly approaching that of rubiadine. i ^f fT 



0*2980 grm. gave 0*7525 carbonic acid and 0*1450 water, 

 corresponding in 100 parts to^ — 



Carbon §£«iiojy iJTiv/ 68*86 -^ ^^ hodanYf bmi 



>4.x.v .. ...;.. . Hydrogen';-?^ iiWQid. 5-40 viogaibflir 'gimn-J 



: ^o!> uii \q louL Oxygen . d nmi- 25*74 ^i-^M earaoD^d , 



The formation of this body, as well as that of verantine and 

 rubiretine, from chlororubian, I am unable to explain in a sati^-- 

 factory manner. ^ 



If the excess of sulphuric acid, with which the four last bodies 

 have been precipitated, be neutralized with carbonate of lead, 

 the filtered liquid leaves on evaporation a saline mass, which, on 

 being pulverized and treated with warm alcohol, communicates 

 to the latter a reddish-brown colour. The alcoholic liquid, after 

 being filtered from the insoluble matter consisting of sulphate 

 of soda, leaves on evaporation crystals of chloride of sodium sur- 

 rounded by a brown syrup of sugar. 



Action of Chlorine on Chlororubian. — If finely pounded chloro- 

 rubian be mixed with water, and if, after the mixture has been 

 placed in a large bottle or other suitable vessel, a current of 

 chlorine gas be passed through it, no change is perceptible for 

 some time ; but if the bottle be closed, after the space above the 

 liquid has been filled with chlorine, the latter is gradually ab- 

 sorbed, the colour of the chlororubian becomes paler, and after 

 several days it appears perfectly white. The process is not 

 accelerated by the action of sunlight, but frequent agitation of 

 the liquid and powder with the gas assists it. The white pow- 

 der into which the chlororubian is changed consists of a body to 

 which I will give the name of Per chlororubian. After collecting 

 it on a filter and washing out the chlorine and acid with water, 

 it is to be dissolved in boiling alcohol, from which it crystallizes 

 on the solution cooling in colourless, transparent, flat, four-sided 

 tables, exhibiting a beautiful iridescence. If it should not be quite 

 colourless, it must be redissolved in boiling alcohol, to which a 



