448 
REPORT OF CHEMICAL LABORATORY 
Rotation 
Ash 
Osmotic 
pressure 
Sunt glim 
Rotation 
Ash 
Gum 
Percentage of 
Percentage of 
Rotation of a 10 per cent, solution 
in a 100 mm. tube 
arabinose 
hexoses 
Before 
hydrolysis 
After 
hydrolysis 
Red Talh from barked trees 
4-2'01 
44-74 
■+ 5*05' 
+ 8-05° 
White T.alh. 
— 
— 
+ .')-2r, 
+ 8-12 
Talh fi'om Goz-El-Basabir .. 
43'.39 
44-.31 
+ 5.2G 
+ 7-89 
T.ilh . 
4.''rr)l) 
44-44 
+ 5-lG 
+ 8-.35 
A specimen of Eed Talk gum, wliich liad exuded naturally from the trees and which 
was examined, gave the same rotation as the s])ecimen from barked trees. 
These figures point to the possibility of readily distinguishing the presence of an 
appreciable quantity of Talh gum, which might have been used to adulterate liasliab gum. 
The ash of two specimens of Talh gum was examined, and the figures are :— 
Gum 
Calcium 
Magnesium 
Potassium 
Red Talh (barked) ... 
. rooG4 
0-1914 
0-1984 
White Talh 
. 1-0504 
0-1784 
0-1.333 
These figures represent grammes of metal in 100 grammes of gum. The proportion of 
potassium is mucli lower in these than in Hashab gums. 
A 6 per cent, solution of Eed Talh gum from barked trees was found to give an osmotic 
pressure of 5,5 mm. of mercury. The gum exuding naturally gave a pressure of IS mm. ; 
and White Talh gum 41 mm. All these are very markedly different from any pressure 
developed by Hashal) gums. 
Runt Gum 
A sample of Runt gum was examined with the following results ;— 
Percentage of Percentage of Rotation of a 10 per cent, solution in a 100 mm. tube 
pentoses hexoses Before hydrolysis After hj-drolysis 
57-80 ... 29-21 ... + 7-73" ... + 8-25“ 
A single sample of Rubakh, Kakamut, and Kuk gum respectively was examined in 
the same way. The results are : — 
Gum 
Percentage of pentoses 
Percentage of hexoses 
Rotation of a 10% solution in a 100 mm. tube 
Before hydrolysis After hydrolysis 
Subakh {Comhrctiim., sp.) 
.54-3G 
‘25-,54 
- 4-16° 
+ 5-48° 
Kakamut {Acacia smna) 
.34-74 
— 
- 1-lG 
+ 6--22 
Kuk {Acacia veriuica) ... 
55'7U 
35-G3 
- 0-20 
+ 7-07 
The mineral matter in Kakamnt and Rubakh gum was found to consist of the 
following (grammes in 100 grammes of gum) : — 
Gum 
Calcium 
Magnesium 
Potassium 
Sulphuric Acid (as SO.,) 
Kakamut [ylcaria suma) 
0-.3580 
0-19-24 
0-7846 
— 
Sub.akh (Conihreluin, 
0-6G27 
0-2458 
0-2981 
0-1.5G3 
