1860.] Memorándum on the Irawadi River. 181 



comparecí, and Captain Yule gives bis decisión in favour of the lovver 

 estimate of Mr. Login. The follovving statements of " the áreas 

 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 



Headof Delta 32^ 



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

 found the Irawadi only 80 yards broad and fordable. Assuming the 

 sources in the Khamti mountains as before, the área 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 área of derivation at" 32| 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 River 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 2-10 feet broad and fordable : tliat is, 

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

 about 2 feet. The sectional área 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 área of derivation be taken at one whole degree, the 

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



2 B 



