16 



EGYPTIAN AGRICULTURE. 



ATMOSPHERIC MOISTURE (ABBASSIA OBSERVATORY). 



For curves showing the Average Temperature, the 

 Average Rate of Evaporation, and the Average Humidity, 

 see Appendix. 



The rate of evaporation a> determined at the Abbassia 

 Observatory has been decreasing year by year, probably 

 due to more accurate measurements in recent years. From 

 May 1901 to April 1902, the evaporation as determined 

 at Abbassia amounted to 138*37 cms. This was deter- 

 mined in the shade, but an experiment at Ghizeh, by 

 estimating the evaporation from a tank one metre deep 

 and one square metre in area sunk into the ground, gave 



