BEI’OKT OF CHEMICAL LABORATOHY 
401 
evaporation carried to dryness over the water hatli. Five to ten c.c. of strong alcohol were 
tlien added, the dish heated on the hath and the alcohol brought in contact witli all parts of 
the water-residue. The liquid was tlien passed through a small filter. The extraction with 
alcohol was repeated several times. As considerable alcohol is lost by evaporation the total 
volume of the several extractions did not exceed 10 c.c. 
So applied, the test was found to be much more delicate and satisfactory. In the 
absence of fluorescein, the alcohol remained perfectly colourless, and the addition of a 
minute trace of fluorescein to the original water was sufficient to impart a distinct 
fluorescence to the alcoholic extract. 
S A LT F1! ( ) M L U « W .A UK CO U N T 11Y 
The following is an analysis of a sample of salt collected in the Ijugwarc country by 
K1 Bimbashi Mackenzie, S.M.O. Khartoum District. 
The salt is said to be extracted from the ashes of a burned grass. 
Moisture and organic matter . 
7-58 per cent. 
Mineral matter insoluble in water 
2-18 
Sodium sulphate 
60-G0 
JIagnesium sulphate . . 
0-41) 
Potassium choloride 
1-27 
Undetermined 
1-24 
True salt (sodium ehloride) 
21-73 
Chemical (’omposition of some Sudan Crains 
The results of a number of analyses of Sudan grains are given in the following tables. 
(See pages 402-411.) For readier reference these include the several analyses made 
and reported previously. Dura, in its numerous varieties, forms the principal part of 
this series. 
Attention is especially called to the collection of this grain from the “ Gezira ” by 
Mr. Davie, of the Department of Agriculture and Lands, and the very useful observations 
made by him in their connection. These samples are marked “ W.A.D.” The methods of 
analysis were, briefly, as follows : — 
Moisture was determined by drying in an air oven at about 100^ C. 
Fat, by extraction of the dried sample with anhydrous ether in the Soxhlet apparatus. 
Albuminoids, by calculation from the total nitrogen determined by the Kjeldahl-Gunning 
method, the factor employed being fr25 or (in the case of wheat) 5-68. In some cases 
the albuminoids were also determined by precipitation by cupric hj'droxide (Stutzer’s 
method). Usually practically all the nitrogen in these grains exists as albuminoids. 
Non-nitrogenous extract was determined by difference, the figure for albuminoids being that 
calculated from the total nitrogen. 
Crude fibre was determined by the conventional metliod, which consists in boiling the 
ether-extracted material successively with 1-25 per cent. sul))huric acid and 1'25 per¬ 
cent. sodium hydroxide solutions. The digestions were performed in the simplified 
apparatus figured and described in the Second Eeport of these Laboi’atories. 
Ash was determined by incineration at a low temperature over the spirit flame. 
Delicacy of 
the lest 
Analysis of 
sample of salt 
Sudan grains 
Method of 
examination 
