NUMBER OF WELLS. 173 



i8go and 1S91, and I am therefore in the position to check with 

 some accuracy the statements of my predecessors. It is clear that 

 the highest number of wells ever in existence must have been 

 recorded by this survey, because in addition to new wells there 

 were all the old wells which must have been seen by previous 

 visitors, and I do not think that a well of, say, about 100 feet in 

 depth can disappear without leaving any trace of its existence 

 behind. It is true some of the old wells have been perfectly filled 

 up again, but by various signs (soil soaked with oil, etc.) it is 

 easy to see that a well once existed where there is now only 

 a shallow hole. Now if we know, approximately even, the 

 age of each well, we shall be able to fix with some amount of 

 confidence the possible number of wells at a certain period in the past. 

 It is, however, difficult to say how far the statements about the age 

 of the well are correct, and to provide for a possible mistake I have 

 allowed a fair margin of age for each well, dividing the wells accord- 

 ing to their age in six classes, namely, — 



(a) wells of 5 years of age and less, 



(b) wells of 10 years of age and less, 



(c) wells of 20 years of age and less, 



(d) wells of 35 years of age and less, 



(e) wells of 50 years of age and less, 

 (f) more than 50 years of age. 



This classification should answer for all purposes. The first class will 

 show all wells dug since the annexation, and after deducting the 

 number of wells in the first two classes we should have the 

 number of wells existing during the period to which the letter of 

 the Burmese Minister refers ; the deduction of the first three classes 

 should show the number of wells at Captain Strover's time; and the 

 four first classes being deducted we should find the number of wells 

 in existence at the time when Captain Yule visited the oil-fields. 

 The following table will show the number of wells in each 



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