1SG0.] Memorandum on the Irawadi River. 181 



compared, and Captain Yule gives his decision in favour of the lower 

 estimate of Mr. Login. The following statements of " the areas 

 drained by the Irawadi in different parts of its course, assuming its 

 sources in the Khamti mountains" are taken from Captain Yule's 

 note: 



Below Magoung River 5f square degrees. 



At Amarapura 13| ,, 



At Prome 31 „ 



Head of Delta 32£ 



To these I may add Moong Khamti in lat. 27° 26' where Wilcox 

 found the Irawadi only SO yards broad and fordable. Assuming the 

 sources in the Khamti mountains as before, the area of drainage will 

 be only three quarters of a degree, or certainly less than one degree. 



15. Now taking the discharge at the head of the Delta at 75,000 

 cubic feet, and the area of derivation at 32J degrees, the volume of 

 water will be 2,300 cubic feet per square degree of country drained. 

 The discharge at each of the above points will therefore be as follows : 



Moongkhamti 1,733 cubic feet. 



Below Magoung Biver 13,175 „ 



At Amarapura 31,050 „ 



At Prome 71,300 „ 



As the calculated discharge at Prome is within two hundred cubic 

 feet of the mean discharge obtained by the actual measurements of 

 Dr. McClelland and Lieut. Falconnet, the calculated amounts of 

 discharge at the other points may be assumed as fair approximations 

 to. the truth. 



16. The calculated discharge of the Irawadi at Moong Khamti 

 must now be compared with the state of the river as described by 

 Wilcox. He found the river 210 feet broad and fordable : that is, 

 the greatest depth was not more than 3 feet, and the mean depth 

 about 2 feet. The sectional area would therefore be 480 feet, which, 

 compared with the above calculated discharge of 1,733 cubic feet, 

 would give the mean velocity of the mass of water at 3*61 feet 

 per second ; which is equivalent to a surface velocity of 6T25 feet per 

 second, or somewhat more than 4 miles per hour. 



17. If the area of derivation be taken at one whole degree, the 

 discharge at Moong Khamti will be 2,300 cubic feet, or one-third 



2 B 



