Dr. Schunck on Rubian and its Products of Decomposition. 369 



As this substance does not combine with bases, its atomic 

 weight could not be determined by direct experiment. There 

 are, however, two formula?, both of which agree with the analyses 

 and explain its formation, viz. C 14 H 14 14 and C 12 H 12 12 . 

 Both of these formulae require iu 100 parts — 



Carbon . . . 4000 

 Hydrogen . . 6 -66 

 Oxygen . . . 53'34 



If the formula C 14 H 14 O 14 be the true one, then its forma- 

 tion from rubian admits of an easy explanation. It would then 

 differ from verantine by 9 equivs. of water ; and by adding to- 

 gether 2 equivs. of it and 2 equivs. of rubiretine, the sum would 

 be equal to 1 equiv. of ruqian plus 6 equivs. of water, as the 

 following equation shows : — 



2 eqs. Sugar . = C 28 H 28 28 \ _ TC^H^O 3 ^ 1 eq. Rubian. 

 2 eqs. Rubiretine = C 28 H 12 Q 8 J~\ H 6 6 = 6 eqs. Water. 



C 56 H 40 36 C 56 H 40 O 36 



If the formula of rubianine be C 28 H 17 O 13 , it may replace 

 rubiretine in the above equation; 11 equivs. of water instead of 

 6 being added to the rubian, as follows, — 



2 eqs. Sugar . =C 28 H 28 28 \_ fC 56 R a4 O 30 =l eq. Rubian. 



1 eq. Rubianine = C 28 H 17 Q 13 J ~ \ H'K) 1 ^ !! eqs. Water. 



C 56 H 45 41 C^H^O 41 



To this view however it may be objected that all the species 

 of sugar capable of fermentation with which we are acquainted 

 contain 12 equivs. of carbon. Indeed it is difficult to conceive 

 how a body of the formula C 14 II 14 O 14 can be decomposed into 

 alcohol and carbonic acid. It is therefore far more probable that 

 the formula of this substance is C 12 H 12 O 12 , which is also that 

 of grape-sugar when dried at 100° C. In fact, were it capable 

 of being crystallized, it would no doubt be considered as iden- 

 tical with grape-sugar. If this be granted, then it follows that 

 the formula of rubianine must be either C 32 H 19 O 15 or C 44 H 24 O 20 , 

 as will be seen by the following equations : — 



2 eq . Sugar . = C 2, II 24 24 \_ J C 5C H 34 O !J0 =sl eq. Rubian. 

 1 eq. Rubianine = C 32 1I I!) 15 J ~ \ IPO 9 =9 eqs. Water. 



QtaftUQaa C 50 !! 43 © 39 * 



Phil. May. S. 4. Vol. 3. No. 19. Man 1852. 2 B 



