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



can afterwards only be purified by repeated solution in boiling 

 alcohol, and deposition from the boiling solution. 



The compound of verantine and oxide of tin, obtained in the 

 process employed for purifying the rubiafine, cannot, as I men- 

 tioned before, be separated into its constituents. It dissolves 

 in ammonia and carbonate of soda with a dark -brown colour, 

 and is reprecipitated unchanged by acids. Even if it be dissolved 

 in caustic soda, and an excess of sulphuretted hydrogen be passed 

 through the solution, the precipitate afterwards produced by 

 acids yields nothing to boiling alcohol, which proves that the 

 verantine has not thereby been set at liberty. By treating it 

 with boiling alcohol until all the matter soluble in alcohol is 

 removed, then dissolving it in carbonate of soda, filtering from 

 a small quantity of oxide of tin, then reprecipitating with acid, 

 it is obtained in dark brown flocks, which when dry cohere into 

 black, brittle, shining masses. Its analysis now gave the fol- 

 lowing results : — 



I. 0-5930 grm., dried at 100° C, gave 0-6500 carbonic acid 

 and 0-1800 water. 



0-3410 grm., heated in a crucible until all the organic matter 

 was destroyed, gave 0-1580 grm. peroxide of tin, equivalent to 

 0-1411 protoxide of tin. 



II. 0-8390 grm. gave 0-9240 carbonic acid and 0*2455 water. 

 It contains therefore in 100 parts — 



I. II. 



Carbon .... 29-89 3003 



Hydrogen . . . 337 3-25 



Oxygen .... 25-36 

 Protoxide of tin . 41-38 



The formula C^H3603^ + 7SnO = 4Ci4H606 + 7SnO + 16HO 

 requires in 100 parts — 



Carbon ...... 29-76 



Hydrogen 3-18 



Oxygen 2552 



Protoxide of tin . . . 41*54 



The sugar obtained by the fermentation of rubian does not 

 differ in its properties, as I mentioned before, from that derived 

 from the action of acids on rubian. In composition too it does 

 not materially differ from the latter. I succeeded, however, by 

 exposing it for a considerable length of time to a temperature of 

 100° C, in depriving it of two atoms more of water, as will be 

 seen by the following analysis : — 



0-5540 grm. gave 0-8745 carbonic acid and 0-3055 water. 



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

 will be seen by the following calculation : — 



