226 



Cholera in Relation to Certain Physical Phenomena. [part i. 



— there is decrease in the amount of individual falls with increased prevalence, and 

 at a third — May — there is increase in the amount of individual falls with decreased 

 prevalence. 



There is nothing in the entire series of data regarding the quantitative and 

 qualitative characters of the rainfall at different times justifying a belief that it 

 exerts any direct action either in producing or diffusing the essential cause of cholera, 

 but, on the other hand, there is some evidence that excessive rainfall exerts a directly 

 opposite action. 



(e) Level of soil-water. / 



TABLE XXIX. 



GoTYvparisoiii of Average monthly Water-level (6 years) and Cholera prevale^ice. 



The above table and the diagram below show the average monthly water-level 

 at the Alipore Jail, where observations on this point have been conducted since 1870. 

 The diagram is constructed on a scale allowing one degree to every 6 inches, and 

 the line showing the fluctuations in level is, as in the diagrams of humidity and 

 rainfall, drawn in a reverse direction, rise on the diagram corresponding to actual 

 fall, and fall to rise of the water. 



Mean Water-level 6 years 

 [Inverted curve]. 



Total monthly Cholera Deaths 

 [38 years]. 



— 14 "7 fi'om surface. 



— 11'-.') 



— 8'-2 



Diagram «.— Average Water-level and Choleia-prevalence in Calcutta. 



The average water-level for the entire year is 12'- 4. The average annual fluctuation 

 in level is 6 '4. 



