430 Dr. Schunck on Rubian and its Products of Decomposition, 



In 100 parts — 



Carbon 57*93 



Hydrogen 2 '84 



Oxygen 39-23 



With another portion of the recrystallized potash salt I pre- 

 pared some silver salt, as before. 0*6260 grm. of the silver salt 

 gave 1*0340 carbonic acid and 0*1070 water, corresponding in 

 100 parts to — 



Carbon 45*04 



Hydrogen 1*89 



The mother-liquor of the salt from which No. III. was made 

 I precipitated with muriatic acid. Part of the precipitate I dis- 

 solved again in carbonate of potash, and the acid from the cry- 

 stallized potash salt showed the following composition : — 



IV. 0*4010 grm. gave 0*8690 carbonic acid and 0*1160 water. 

 In 100 parts- 

 Carbon 59*10 



Hydrogen 3*21 



Oxygen 37*69 



The remainder of the precipitate I now dissolved again in per- 

 nitrate of iron, and after keeping the solution boiling for several 

 hours I precipitated again with muriatic acid, filtered, washed, 

 dissolved the precipitate in carbonate of potash, filtered and pre- 

 cipitated again with muriatic acid. The precipitated rubiacic 

 acid now gave on analysis the following results : — 



V. 0*3925 grm. gave 0*8240 carbonic acid and 0*1030 water. 

 These numbers correspond with the formula C^^H^O'^, as 



will be seen by the following calculation : — 



Eqs. Calculated. Found. 



Carbon . . 32 192 56*97 57*25 



Hydrogen . . 9 9 2*67 2*91 



Oxygen . . 17 136 40-36 39*84 



S37~ 100-00 100*00 



This composition dificrs, as will be seen, very little from that 

 found in my former experiments. 



Some fresh rubiacic acid made in the same manner as that of 

 the last analysis, was dissolved in carbonate of potash, the solu- 

 tion was evaporated to crystallization, the crystallized potash salt 

 was again dissolved in boiling water, and nitrate of silver was 

 added to the solution. The precipitate was now no longer red, 

 but of a dull orange colour. 



0*1700 grm. of this precipitate gave 0*2720 carbonic acid and 

 00370 water =43*63 per cent. C and 2*40 H; the formula 

 CM H8 0»6 + AgO requires 43*24 C and 1*80 H. 



