Below the island the river was 100 m. wide and very shallow—not more than from 1 to 4 ft. in depth. We halted at sunset, having gone that day 92 kil. 300 m.
During the night of July 11th my men suffered a great deal from cold, the thermometer being as low as 45° Fahrenheit. In the morning there was a thick fog over the river—so thick that we had to delay our departure until eight o'clock, as we could not see more than two or three metres ahead.
Two kilometres beyond we came to a rivulet, 2 m. wide, on the left bank, and soon after to a small corrideira with a navigable channel in the centre. Three hundred metres farther down we passed another tributary on the right bank. There was open country with sparse stunted trees on the left of us, thick forest with plenty of rubber trees on the right. I noticed several good specimens of the pao dolce—a tree with a curious cluster of yellow flowers not unlike the flower of wistaria upside down. Not only was the pao dolce pretty to look at, but a most refreshing beverage could be made from a decoction of its leaves.
The course of the river was winding, with basins and rapids of no great importance. Another tributary 2 m. wide was reached on the left bank, and soon after another tiny streamlet entered the Arinos from the same side.
I had a narrow escape. One of the men, who was sitting behind me in the canoe, saw an ariranha (Lutra Brasiliensis) put its head out of the water only ten metres in front of the canoe. In his great hurry to kill the beautiful animal he seized his rifle and emptied the eight shots out of his magazine, firing the first three shots close to my head on the left side, the other five just as close on the other side. The muzzle of his rifle was so near my ear that the noise deafened me for several minutes and my hair was almost singed off. The ariranha, needless to say, escaped unhurt, and luckily so did I.
We went over a long strip of shallow water from 1 to 3 ft. deep. We now had open country on the right bank, with a small streamlet finding its way into the Arinos on that side. The river was flowing again in long straight stretches—3,000 m., 2,000 m., 2,500 m. in length. In the portions where the banks were thickly wooded innumerable rubber trees were to be seen.
In the centre of a basin 150 m. wide we found another island, 100 m. long and 50 m. wide, absolutely smothered in vegetation and with a handsome gravel spit at its southern end. Two kilometres farther another basin, 300 m. broad, appeared. An amazing quantity of rubber trees was to be seen round that basin. Near the water we also found fine specimens of the mate (Ilex Paraguayensis St. Hil.), with its wax-like leaves, much used in certain parts of South America for making a kind of tea.
For close upon 13 kils. the river flowed—with slight deviations—almost always due north, and with its limpid waters was of extraordinary beauty. The country was open on the right side of us. We saw that day two white urubú (Cathartes). The Brazilians have a curious superstition about them. They say that if you write with a quill taken from the wing of one of these birds any business which you may be transacting will go well; in fact, anything you may wish to do and which you set down on paper with one of these quills and ink is sure to turn out successfully.
That day I again suffered much, while taking astronomical observations, from the millions of bees and other insects which settled in swarms upon my hands and face and stung me all over. We were then in lat. 12° 26′·5 S., long. 56° 37′ W. The temperature in the sun was not unbearable—merely 85° Fahr.
In the afternoon, after we had enjoyed an excellent lunch of fish, tinned provisions, and rice—my men also enjoying their feijao (boiled beans)—we continued our journey. The river for 9,000 m. displayed first clean campos and chapada on the left bank and dense forest on the right, then campos on the right bank and a belt of forest along the river on the left.
