58 ROYAL ASIATIC SOCIETY, ( CEYLON BRANCH.) 



similar diagram to the corresponding readings in the shade, 

 but of course at a considerable distance above for maximum, 

 and below for minimum readings. This distance, as will be 

 seen, varies inversely as the rainfall. In understanding the 

 diagrams the rise or fall of the line is more to be considered 

 than its length, as in the case of the thermometer the 

 exposed ones naturally vary more from their mean than 

 those in shade. In the rainfall diagram the verticle dis- 

 tances from the base line A. B. to the various points, 

 multiplied by 12J give in inches the actual quantity that 

 fell in any month. 



E. HEELIS, 



