"The Rio Negro broadens considerably from its mouth upward, and presents the appearance of a great lake; its black-dyed waters having no current, and seeming to be dammed up by the impetuous flow of the yellow, turbid Solimoens, which here belches forth a continuous line of uprooted trees, and patches of grass, and forms a striking contrast with its tributary. In crossing, we passed the line a little more than half-way over, where the waters of the two rivers meet, and are sharply demarcated from each other. On reaching the opposite shore, we found a remarkable change. All our insect pests had disappeared, as if by magic, even from the hold of the canoe: the turmoil of an agitated, swiftly-flowing river, and its torn, perpendicular, earthy banks, had given place to tranquil water, and a coast indented with snug little bays, fringed with sloping, sandy beaches. The low shore, and vivid, light-green, endlessly varied foliage, which prevailed on the south side of the Amazons, were exchanged for a hilly country, clothed with a sombre, rounded, and monotonous forest. A light wind carried us gently along the coast to the city of Barra, which lies about seven or eight miles within the mouth of the river. "The town of Barra is built on a tract of elevated but very uneven land, on the left bank of the Rio Negro, and contained, in 1850, about three thousand inhabitants. It is now the principal station for the lines of steamers which were established in 1853; and passengers and goods are trans-shipped here for the Solimoens and Peru. A steamer runs once a fortnight between Pará and Barra; and another as often between this place and Nauta, in the Peruvian territory." MAMELUCOS, OR HALF-BREEDS.