217 
1915-1(7] Note on the Sublimation of Sugars. 
being used as a condenser, cold water passing through it, the arrangement 
being as in the diagram. The sugar was placed in the bottom of the outer 
test-tube, which was then immersed in an oil-bath. With a pressure of 1 
to 2 mm. and a temperature of 105°, sublimation took place, a transparent 
layer forming on the lower end of the condenser tube. Analysis of 
some sublimate kept over phosphoric anhydride for two days (I) and for 
seven days (II) gave the following results : — 
Found. 
Calculated 
I. 
II. 
for C 6 H 12 0 5 , jH 2 0 
for C 6 H 12 0 5 . 
C = 42-90 
42*93 
42-73 
43-90 
H= 7-39 
7*38 
7-42 
7-31 
The substance being hygroscopic may account for the discrepancy 
from the theoretical values for the anhydrous substance, but it is curious 
that the figures coincide so closely with those required for 0 6 H 12 0 5 , iH 2 0. 
The quantity of sublimed substance being small, the specific rotation was 
measured in a one-decimetre tube of about one cubic centimetre capacity. 
To test the accuracy of such measurement, a comparison of the values 
obtained with this tube and those obtained with a two-decimetre jacketed 
tube using a less pure specimen of rhamnose hydrate was made, and the 
values found to be in close agreement. The values for the sublimed 
substance were : — 
For cone. = 4T266 . . . Fal— — +9 21° 
L J 1 ) 
For cone. = 4-000 . . . [al— B+9'00 0 
L J L> 
which closely agrees with the value obtained by Fischer : — 
90 
For cone. = 3*4208 . . = 9-24 J 
(Ber., 1895, 28 , 1162). 
