REPOKT OF CHEMICAL LABORATORY 
Special 
research on 
gum-arabic 
The water of 
the Blue and 
White Niles 
3S(i 
A very large shai'o of the analytical work has been carried out hy the assistant chemist, 
i\lr. (foodson. 
Owing to the greatly increased volume of routine work, the opportunities for pure 
research have not been many; but the examinations of the Nile waters, and the verv great 
number of examinations of gum, were all in this direction. We were very fortunate this 
year in being able to secure the services of IMr. E. S. Edie, E.Sc., Carnegie Research Fellow, 
who was detailed by the Committee of the Carnegie Trust to carry out researches in Sudan 
gum. i\[r. Edie’s work, as well as our own, was very much hampered by the failure, 
through a misuuderstauding, of the Woods and Forests Department to supj)ly the essential 
samples of gum, and, further, by the fire which destroyed the bacteriological laboratory in 
which he was carrying out his experiments on the bacterial pioductiou of gum. Xotwith- 
stauding these misfortunes, i\Ir. Edie has been able to offer a very siihstantial contnhutiou to 
our knowledge of the chemistry of gums, as will he seen by reference to his Report, which is 
attacheil to this. 
Chemical Comtosition of Xile Waters 
In the Second Report of these Laboratories the results of periodical examinations of 
the waters of the Blue Nile and White Nile were given for a period of a year ending 
November, 1905. The examinations continued up to the month of INIay, 1907, were more 
complete both as to the determinations of amount of suspended material and of the 
quantity and nature of the dissolved matter. These results, along with those obtained 
for the previous year, are tabulated on the following pages. The figures representing 
solid matter in suspension are usually the average of several (in the flood season, weekly) 
examinations. The others represent determinations on a single sample collected about the 
middle of each month. 
As before, the samp)les from the Blue Nile were taken opposite the far end of Burre, 
about a mile bejmnd the built-up portion of Khartoum. Those of the White Nile water were 
collected from a point about two miles above its junction with the Blue Nile. 
The proportion of CO,, recorded represents simply the measure of the alkalinity 
determined by direct titration with acid. 
