June, 1850. CHATTUC. BROWN AND TRANSPARENT RIVERS. 263 



twenty miles of the Khasia ; they are chiefly formed of 

 stratified gravel and sand, and are always occupied by 

 villages and large trees. They seldom exceed sixty feet in 

 height, and increase in number and size as the hills are 

 approached ; they are probably the remains of a deposit 

 that was once spread uniformly along the foot of the 

 mountains, and they in all respects resemble those I have 

 described as rising abruptly from the plains near Titalya 

 (see vol. i. p. 382). 



The climate of Chattuc is excessively damp and hot 

 throughout the year, but though sunk amid interminable 

 swamps, the place is perfectly healthy ! Such indeed is 

 the character of the climate throughout the Jheels, where 

 fevers and agues are rare ; and though no situations can 

 appear more malarious to the common observer than 

 Silhet and Cachar, they are in fact eminently salubrious. 

 These facts admit of no explanation in the present state of 

 our knowledge of endemic diseases. Much may be attri- 

 buted to the great amount and purity of the water, the 

 equability of the climate, the absence of forests and of 

 sudden changes from wet to dry ; but such facts afford 

 no satisfactory explanation. The water, as I have above 

 said, is of a rich chesnut-brown in the narrow creeks 

 of the Jheels, and is golden yellow by transmitted light, 

 owing no doubt, as in bog water and that of dunghills, to 

 a vegetable extractive aud probably the presence of car- 

 burctted hydrogen. Humboldt mentions this dark-coloured 

 water as prevailing in some of the swamps of the Cassi- 

 quares, at the junction of the Orinoco and Amazon, and 

 gives much curious information on its accompanying 

 features of animal and vegetable life. 



The rains generally commence in May. they were 

 unusually late this year, though the almost daily gales and 



