3 8o 



THE FERTILITY OF SOILS IN THE TROPICS 



there was a substantial rise, and for a time it appeared 

 as though our forecast was to be wrong, but the rise 

 was of very short duration, and at the beginning of May 



DIAGRAM IV. 

 FORECAST OF THE SPRING RAINS. 

 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 



Metres 

 .+1.0 



+0.4 

 *0.2 



3 



-0.2 

 -0.4 



\ . 



/ 

 LL 



Predicted Roheii 

 Actual Roseires 



es Gauge. 

 Gauge. 



(MeanofMay)-(Meanof March). 



( H 



levels again fell very rapidly and the actual mean level 

 in the Blue Nile at Roseires was only 10 centimetres from 

 the forecasted value. 



