MR. SCHUNCK ON RUBIAN AND ITS PRODUCTS OF DECOMPOSITION. 457 
action of nitric acid is oxalic acid. It is not precipitated from its watery solution by 
any metallic or other salt, not even by basic acetate of lead. On the addition of 
caustic potash or soda to its solution and boiling, the solution immediately becomes 
brown, and a brown powder falls, just as in the case of grape-sugar. It is capable of 
fermentation. The watery solution when mixed with yeast soon begins to ferment, 
though the process is not so lively as in the case of an equal quantity of common 
sugar ; and by distilling the liquid and boiling the distillate with dry carbonate of 
soda, alcohol may be obtained. 
The analysis was attended with some difficulty on account of the great affinity 
which it has for water. By heating it however for some time at 100° C., then allowing 
to cool and pulverizing while in its brittle state as quickly as possible, it was obtained 
in a condition fit for analysis. Even then however the state of hydration was not 
uniform, so that the analyses differed considerably from one another. The following 
results were obtained : — 
I. 0'4765 grm., burnt with chromate of lead, gave 0'6860 carbonic acid and 0‘2905 
water. 
II. 0*3050 grm. gave 0*4450 carbonic acid and 0*1815 water. 
III. 0*3820 grm. gave 0*5650 carbonic acid and 0*2205 water. 
These numbers give in 100 parts — 
I. 
II. 
III. 
Carbon . 
. . . 39*26 
39*79 
40*33 
Hydrogen 
. . . 6*77 
6*61 
6*41 
Oxygen . 
. . . 53*97 
53*60 
53*26 
As this substance does not combine with bases, its atomic weight could not be 
determined by direct experiment. There are, however, two formulae, both of which 
agree with the analyses and explain its formation, viz. C ^4 H 44 O 44 and C 42 H 42 Oj 2 . 
Both of these formulae require in 100 parts — 
Carbon 40*00 
Hydrogen .... 6*66 
Oxygen 53*34 
If the formula" C 44 H 14 O 44 be the true one, then its formation from rubian admits 
of an easy explanation. It would then differ from verantine by 9 equivs. of water ; 
and by adding together 2 equivs. of it and 2 equivs. of rubiretine, the sum would be 
equal to 1 equiv. of rubian plus 6 equivs. of water, as the following equation shows *. — 
2 equivs. of Sugar . . =C 28 H 28 O 28 I rC 5 e H 34 030=1 equiv. of Rubian. 
2 equivs. of Rubiretine =C 28 H 42 O gj 1 H g O g =6 equivs. of Water. 
^-56 ^’^40 ^36 ^56 ^40 ^36 
If the formula of rubianine be C 28 Hj; O 43 , it may replace rubiretine in the above 
equation ; 11 equivs. of water instead of 6 being added to the rubian, as follows, — 
2 equivs. of Sugar . . =C 28 H 28 023 '! _ fCgg H 34 030=1 equiv. of Rubian. 
1 equiv. of Rubianine . =C 28 H 47 0i3J 1 H 44 Oi 4 = 1 1 equivs. of Water. 
^56 H45 ^41 Q')6 ^45 ^41 
