Chap. VI. STRAITS OF OBYDOS. 237 



the Trombetas, a large river flowing through the interior 

 of Guiana. Hills and lowlands alike are covered with a 

 sombre rolling forest. The river here is contracted to a 

 breadth of rather less than a mile (1738 yards), and the 

 entire volume of its waters, the collective product of a 

 score of mighty streams, is poured through the strait 

 with tremendous velocity.* It must be remarked, 

 however, that the river valley itself is not contracted 

 to this breadth, the opposite shore not being continental 

 land, but a low alluvial tract, subject to inundation 

 more or less in the rainy season. Behind it lies an 

 extensive lake, called the Lago Grande da Villa Franca, 

 which communicates with the Amazons, both above 

 and below Obydos, and has therefore the appearance of 

 a by-water or an old channel of the river. This lake 

 is about thirty-five miles in length, and from four to ten 

 in width ; but its waters are of little depth, and in the 

 dry season its dimensions are much lessened. It has 

 no perceptible current, and does not therefore now 

 divert any portion of the waters of the Amazons from 

 their main course past Obydos. 



I remained at Obydos from the 11th of October to 

 the 19th of November. I spent three weeks here, also, 



* It was formerly believed that the river at the strait of Obydos 

 could not be sounded on account of its great depth and the velocity of 

 the current. Lieut, Herndon, of the United States navy, succeeded in 

 doing so, however, in 1852. He found a depth of 30 to 35 fathoms, 

 but in one place he thought he had not touched the bottom at 40 

 fathoms. Von Martins, estimating the depth in the middle at 60 

 fathoms, and on the side at 20, and the velocity of the current at 2*4 

 feet per second, estimated that 499,584 cubic feet of water passed through 

 the strait in each second of time. The tides are felt here in the dry 

 season, but the flood does not press back the cuiTcnt of the Amazons. 



