246 



FLORA INDICA. 



island of Cheduba, and if so, the latter is the northern limit 



of that tree. 



7. Ava and Pegu. 



The sources of the river Irawadi are, according to the best 

 authorities, between 27° and 28° of north latitude, and the 

 direction of its valley is nearly due north and south. The 

 mountains in which this immense river takes its rise probably 

 rival in height the Eastern Himalaya, but the meridional 

 ranges which bound its valley on each side do not long re- 

 tarn any great elevation, though they are continuously from 

 4000 to 8000 feet in height almost as far as the sea. The 

 transverse range, which separates the upper part of the west- 

 ern branch of the Irawadi from the valley of Assam, is also 

 of moderate elevation, varying probably between 5000 and 

 6000 feet. 



The slope of the valley of the Irawadi is greater than that 

 of the Indus or Ganges, if the estimates of elevation given by 

 Griffith may be relied on. The valley of Hukum is stated to 

 be 1000 feet above the level of the sea. The determination 

 however was made by boiling water, which, at such low levels, 

 is too fallacious a test to be depended on. The central branch 

 of the Irawadi, at Manchi in 27° 20' north latitude, where it 

 was visited by Wilcox, has an elevation of 1800 feet*, and 

 runs over a pebbly bed. Its elevation at Bhaumo, in lat. 

 24°, is estimated by the same authority to be about 500 feet. 

 The valley of the Irawadi is much less open than that of 

 the Ganges, being interrupted in many places by transverse 

 ranges. In the upper part of its course these are numerous, 

 and the lateral valleys they enclose are comparatively small ; 

 but lower down there is a great expanse of level country, 

 though the hills occasionally attain an elevation of 3000 or 



4000 feet close to the river. 



The direction of the monsoon wind in the valley of the 

 Irawadi appears to be nearly from south to north. The 



* As. Res. xvii. 441. 



