The temperature of the waters of the Irrawaddi is as usually obtains, except during the rises of the river caused by the melting of snow, when it is higher than usual.

Tributaries of the Irrawaddi between Mogoung river and Ava.

The number of tributaries even to Rangoon is unprecedentedly small:  this tends to increase the astonishment with which one regards this magnificent river.

The rivers that fall into the Irrawaddi within the above distance are,

1st.  The Mogoung river.

2nd.  Tapien Khioung, above Bamo.

3rd.  Shewe Lee Khioung.

These are about the same size, and only discharge a considerable quantity of water during the rainy season.  The Shewe Lee at its mouth, is between 5 and 600 yards wide, but only an inconsiderable portion of this is occupied by water, and this to no depth.

The great branch from which the Irrawaddi derives its vast supply of water still remains to be discovered, and will probably be found to be the Shoomaee Kha.  It is evident, at any rate, that the great body of water comes from the eastward, for between the Mogoung river and Borkhamtee, in which country Captain Wilcox visited the Irrawaddi, and where it was found to be of no great size, no considerable branch finds its way from the Westward:  neither are the hills which intervene between these points, of such height as to afford large supplies of water.

On the whole it is, I think, probable, that the Irrawaddi is an outlet for some great river, which drains an extensive tract of country; for it appears to me that if all its waters are poured in by mountain streams, a tract of country extensive beyond all analogy, will be required for the supply of such a vast body of water.

In addition to the above three rivers, few nullahs exist, but these are scarcely worthy of consideration.

Nature of the country.—­From the mouth of the Mogoung river nearly to Tsenbo the country is flat, and the banks wooded or covered with grass to the brink.  The range of hills which form the upper Kioukdweng there commence, and continue for a distance of 16 or 20 miles, during the whole of which they form the banks of the river.  These hills are scantily covered with trees, most of which are in addition stunted.  The vegetation within the maximum high water mark consists of a few scraggy shrubs.  The rocks composing these hills are principally serpentine, which within the influence of the water is of a dark sombre brown colour.  Limestone occurs occasionally.