Dr. Schunck on Rubian and its Products of Decomposition. 429 



The most probable formula for this substance is C^^H^' 0^°, 

 which requires in 100 parts — 



Carbon ...... 67*84 



Hydrogen 3-88 



Oxygen 28-28 



The remainder of the substance I dissolved in boiling alcohol, 

 and added acetate of lead. This gave a dark red precipitate, 

 which after filtering, washing with alcohol, and drying, was 

 found to have the following composition : — 



0*5470 grm., dried at 100° C, gave 0*6630 carbonic acid and 

 0*0890 water. 



0*4060 grm. gave 0*2800 sulphate of lead, containing 0*20602 

 oxide of lead. 



These numbers correspond with the formula 3O^^H^*0'® 

 + 8PbO, as the following calculation shows : — 



Eqs. Calculated. Found. 



Carbon . . 96 576 3305 33*05 



Hydrogen . . 33 33 1*89 1*80 



Oxygen . . 30 240 13*78 14*41 



Oxide of lead. 8 893*6 51*28 50*74 



1742-6 100-00 100*00 



The precipitate produced by muriatic acid in the nitrate of 

 iron solution, was not entirely soluble in boiling alcohol. That 

 part left undissolved by the latter 1 dissolved again in nitrate of 

 iron ; I kept the solution boiling for some time, and then pre- 

 cipitated again with muriatic acid. The precipitate, after filter- 

 ing and washing, 1 treated with a boiling solution of carbonate 

 of potash, in which it dissolved. On cooling, a considerable 

 quantity of rubiacate of potash crystallized out with its usual 

 appearance. Some of this salt was decomposed with nitric acid, 

 and the rubiacic acid so obtained was analysed. 



II. 0*5250 grm. gave 1*1595 carbonic acid and 0*1465 water. 

 In 100 parts — 



Carbon ...... 60*23 



Hydrogen 3*10 



Oxygen ...... 36*67 



These numbers do not differ very widely from those found in 

 the first analysis. On recrystallizing, however, the remainder 

 of the salt from water, and analysing some acid obtained from the 

 recrystallized salt, I obtained the following numbers : — 



III. 0*4300 grm. gave 0*9135 carbonic acid and 0*1100 water. 



