Cuap. VI. THE MAIN STREAM. 117 
October 3rd.—About midnight the wind, for which we had long been 
waiting, sprang up, the men weighed anchor, and we were soon fairly 
embarked on the Amazons. I rose long before sunrise, to see the great 
river by moonlight. There was a spanking breeze, and the vessel was 
bounding gaily over the waters. The channel along which we were 
sailing was only a narrow arm of the river, about two miles in width :. 
the total breadth at this point is more than 20 miles, but the stream is 
divided into three parts by a series of large islands. ‘The river, not- 
withstanding this limitation of its breadth, had a most majestic 
appearance. It did not present that lake-like aspect which the waters 
of the Para and Tocantins affect, but had all the swing, so to speak, of 
a vast flowing stream. The ochre-coloured turbid waters offered also a 

Acari Fish (Loricaria duodecimalis). 
great contrast to the rivers belonging to the Parad system. The channel 
formed a splendid reach, sweeping from south-west to north-east, with 
a horizon of water and sky both up stream and down. At 11 a.m. we 
arrived at Gurupa, a small village situated on a rocky bank 30 or 4o 
feet high. Here we landed, and I had: an opportunity of rambling 
in the neighbouring woods, which are intersected by numerous path- 
ways, carpeted with Lycopodia growing to a height of 8 or 10 inches, 
and enlivened by numbers of glossy blue butterflies of the Theclidze or 
hair-streak family. The land on which Gurupd is built appears an 
isolated rocky area, for the rest of the country round about lies low, and 
is subject to inundation in the rainy season. At 5 p.m. we were again 
under weigh. Soon after sunset, as we were crossing the mouth of the 
Xingu, the first of the great tributaries of the Amazons, 1200 miles in 
length, a black cloud arose suddenly in the north-east. Joao da Cunha 
ordered all sails to be taken in, and immediately afterwards a furious 
squall burst forth, tearing the waters into foam, and producing a 
frightful uproar in the neighbouring forests. A drenching rain followed: 
but in half an hour all was again calm, and the full moon appeared sailing 
in a cloudless sky. . 
From the mouth of the Xingu the route followed by vessels leads 
straight across the river, here 10 miles broad. ‘Towards midnight the wind 
