MR. SCHUNCK ON RUBIAN AND ITS PRODUCTS OF DECOxMPOSITlON. 89 
I am unwilling to draw any inference from the greater or less correspondence of 
either of these calculations with the experimental result, because I am not convinced 
of the absolute purity of the specimen employed for analysis. 
The lead compound of rubiagine was prepared by adding a small quantity of an 
alcoholic solution of sugar of lead to a concentrated alcoholic solution of the sub- 
stance, taking care not to employ an excess of the precipitant. The orange-coloured 
precipitate was collected on a filter, washed with alcohol, dried and submitted to 
analysis. 
0-4610grm., dried in the water-bath, gave 0*5290 carbonic acid and 0*1110 water. 
0*2010grm. gave 0*1460 sulphate of lead, containing 0*10742 oxide of lead. 
In 100 parts it contained therefore — 
Carbon 31*29 
Hydrogen 2*67 
Oxygen 12*60 
Oxide of lead 53*44 
These numbers do not decide between the two formulae, since they correspond 
equally well with C 32 Hu Oio+3PbO and C 44 H 17 0 , 3 + 4 Pb 0 , as the following calcula- 
tion shows : — 
Carbon - . . 
Eqs. 
32 
192 
30*91 
Eqs. 
44 
264 
31*73 
Hydrogen . . 
14 
14 
2*25 
17 
17 
2*04 
Oxygen . . . 
10 
80 
12*89 
13 
104 
12*53 
Oxide of lead . 
3 
335*1 
53*95 
4 
446*8 
53*70 
621*1 
100*00 
831*8 
100*00 
If CgaHuOio be the true formula of rubiagine, then it is formed by rubian taking 
up 4 equivs. of water and splitting up into 1 equiv. of rubiagine and 2 equivs. of 
sugar, as seen by the following equation *. — 
2 equivs. of Sugar . . . =€24 H 24 024 irC 56 H 34 030 = 1 equiv. of Rubian. 
1 equiv. of Rubiagine . . =C 32 HuOioJ 1 H 4 O 4=4 equivs. of Water. 
C56 H30 O34 C5g H3g O34 
If, on the other hand, C 44 H ,7 be the correct formula, then 1 equiv. of rubian loses 
5 equivs. of water, and splits up into 1 equiv. of rubiagine and 1 equiv. of sugar, for 
C 44 H,. Oi3~l“Ci2 H ,2 Oi2+5HO=C56 H 34 033 . 
Rubiadipine . — This substance is a characteristic product of the fermentation of 
rubian. I have never subjected rubian to the action of ferment, under ordinary 
circumstances, without being able to detect it among the bodies formed. In its 
appearance and general properties it resembles rubiretine. It differs from the latter 
in always remaining soft and viscid, and never becoming hard and brittle, however 
long it may be heated. It is similar in appearance to a semifluid fat tinged with 
