YENANGYOUNG. 



69 



The above figures prove distinctly, as will be more readily seen 

 from the diagram fig. 2, that there is unquestionably a periodicity 

 of production, which is intimately connected with the season. The 



4 



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1 



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t 



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a. 

 JS 

 xn 







O 



1 







PI 



CO 



660000 



























660000 



650000 

























' 



050000 



640000 

















\ 











640000 



670000 

















\ 





/ 







630000 



620000 

















\ 



> 



/ 







620000 



610000 

















\ 



/ 









61O000 



600000 



























600000 



590000 



























590000 



580000 



























580OO0 



570000 



























570000 



560000 



























56 OOOO 



550000 



























550000 



540000 



























54-0000 



530000 



























53000O 



520000 



























520000 



510000 



























510000 















... 1 















Fig. 2. Diagram showing the mean monthly yield of petroleum from 1886 to 1894. 



year begins with a comparatively low production in January, which 

 is followed by a quick drop in February, and a sudden rise in March, 

 after another drop in April, the production quickly rises till it has 

 reached its maximum in July, a rather sudden, but not large, drop 

 takes place up to September, when it again slowly rises till November, 

 only to fall largely and suddenly in December, a drop which lasts till 

 February. Now, is it a mere coincidence that the curve, as above 

 depicted, represents in some rough way the line illustrating the rise 

 and the fall of the Irawadi ? Unfortunately no exact observations 

 regarding the river gauge have been made at Yenangyoung, but 

 experience has proved that the river reaches its lowest level in 

 February, a small rise takes place in March, probably owing to the 

 snow water coming down from the upper regions of the catchment 

 area, and then another fall takes place in April. From May the river 

 rises until it has reached its maximum level during the months of June, 

 July or August; it falls slowly till November, but thence to February 

 the fall is quick and considerable. 



