LIST OF ILLUSTRATIONS 



FIG. 



1. Graph showing the Average Monthly Rainfall of five 



Places in the Great Palaearctic Desert . . p. 7 



2. Graph showing the Average Monthly Rainfall of five 



Places in the Indian Desert . . . . p. 8 



3. Graph showing the Average Monthly Rainfall of four 



Places in the Deserts of the Southern States of the 

 U.S.A. The distribution of rainfall shown in this 

 graph is not characteristic of stations in every part of 

 these deserts . . . . . . . p. 9 



4. Graph showing the Average Monthly Mean Shade 



Temperatures of three Places in the Great Palsearctic 

 Desert p. 16 



5. Graph showing the Monthly Mean Maximum and Mean 



Minimum Shade Temperatures of four Places in the 

 Great Palaearctic Desert . . . . p. 18 



6. Graph showing the Monthly Mean Maximum and Mean 



Minimum Shade Temperatures of three Places sit- 

 uated on the Sea Coast of the Great Palaearctic 

 Desert p. 21 



7. Curve obtained from Recording Instrument showing 



daily Fluctuation in Relative Humidity at Gizeh, 

 Egypt, 20th-22nd March, 1922. The figures on the 

 side of the graph represent percentages of humidity 

 (C. B. Williams) p. 24 



8. Graph showing the Relative Humidity at Mosul, N. 



Mesopotamia, at 8 a.m. and 4 p.m. during an average 

 Week in June and an average Week in December p. 25 



9. Graph showing the Mean Relative Humidity at Two- 



hourly Intervals for the Months June, July, August, 

 and September at Mohammerah, Persian Mesopo- 

 tamia p. 26 



