216 
Proceedings of the Royal Society of Edinburgh. [Sess. 
XII.— Note on the Sublimation of Sugars.* By Sudhamoy Ghosh, 
D.Sc. (Edin.). Communicated by Professor J. Walker, F.R.S. 
(MS. received December 8, 1915. Read January 10, 1916.) 
The literature of the sugars would appear to show that no sugars have 
hitherto been observed to sublime with the exception of glycolose, 
CH 2 OH 1 CHO, which is described as being “ perceptibly volatile with 
water and alcohol vapour under diminished pressure, especially from a 
pure, concentrated solution ” (Lippmann, Chemie dev Zuckerarten , p. 4). 
This substance, being the first of the sugar series, might be expected to 
have properties somewhat different from the other members of the series, 
which are usually looked upon as non-volatile. Experiments with 
rhamnose and fructose appear to show that under diminished pressure 
they do sublime. 
Rhamnose. 
In an experiment in which a sample of rhamnose (Kahlbaum) was 
heated under diminished pressure in the steam-jacketed drying apparatus 
described in a paper by Mackenzie and Ghosh ( Proc . Roy. Soc. Edin. y 
1914-15, vol. xxxv, p. 22) a sublimate was obtained, which had a sweet 
taste and charred on heating;. 
In further experiments a sample of rhamnose hydrate, for which I 
am indebted to Professor Walker, was used. This sample gave the 
following data: — Melting-point 82° to 92°; [a]^=+8‘R3° (Fischer and 
Piloty give for the monohydrate +8° to 9° \Ber., 1890, 23, 3102]); 
on analysis : — 
Found. 
Calc, for C 6 H 12 0 5 , H 2 0. 
Calc, for C 6 H 12 0 5 . 
C = 39‘38 per cent. 
39-55 
43-90 
H= 7-71 „ 
7*69 
7-31 
The sublimation was carried out in a simple apparatus consisting of a 
larger and a smaller test-tube, each having a side tube, the inner test-tube 
* [The author’s departure for India prevented him continuing the work of which this is a 
preliminary note. The Council considered that in the circumstances the observation was 
worthy of being recorded. — C. G. K., Sec.] 
