— 62 — 
Dr. Mackenzie of 1896/97/98. The year 1874 was an extraordinarily 
high flood. 
Month. 
PARTS 
IN 100,000 OF WATER 
Dr. Mackenzie. 
Dr. Letheby. 
The Mean 
of the two 
January • • 
31*0 
16*7 
27*4 
February .. . . 
25*3 
12*6 
22*1 
March . . 
12*7 
5*3 
10*9 
April 
15*8 
6*6 
13*5 
May., 
14*7 
4*8 
12*2 
June . . . . . 
14*1 
6*9 
12*3 
July 
13*9 
17*8 
14*8 
August 
159*0 
149*2 
156*6 
September 
156*1 
53*3 
130*4 
October 
110*0 
37*8 
92*8 
November 
70*8 
34*4 
61*7 
December 
47*0 
28*9 
42*4 
Mean 
56*0 
31*3 
49*8 
From this last column M. Barois concludes that in high floods 
100,000,000 tons of solid matter pass Assuan, and 88,000,000 in mean 
floods. It is unfortunate that we have no analyses of low floods like 
1877, 88, 99, 1902 and 1904 which were extraordinarily muddy. The 
water had little sand but much mud. The sand is scoured out of the 
bed of the river itself in high floods. 
After Dr. Letheby the composition of Nile deposit is as follows 
In flood. 
In low supply. 
Organic matter 
15*02 
10*37 
Phosphoric acid 
1*78 
*57 
Lime 
2*06 
3*18 
Magnesia 
1*12 
•99 
Potash 
1*82 
1*06 
Soda . . . . . . . . 
*91 
*62 
Alumina and oxide of iron . . 
20*92 
23*55 
Silica 
55*09 
58*22 
Carbonic acid and loss . . . . 
1*28 
1*44 
Total 
100*00 
100*00 
