The actual surveying of the river was done by Colonel Rondon and Lyra, with Kermit as their assistant.  Kermit went first in his little canoe with the sighting-rod, on which two disks, one red and one white, were placed a metre apart.  He selected a place which commanded as long vistas as possible up-stream and down, and which therefore might be at the angle of a bend; landed; cut away the branches which obstructed the view; and set up the sighting-pole—­incidentally encountering maribundi wasps and swarms of biting and stinging ants.  Lyra, from his station up-stream, with his telemetre established the distance, while Colonel Rondon with the compass took the direction, and made the records.  Then they moved on to the point Kermit had left, and Kermit established a new point within their sight.  The first half-day’s work was slow.  The general course of the stream was a trifle east of north, but at short intervals it bent and curved literally toward every point of the compass.  Kermit landed nearly a hundred times, and we made but nine and a third kilometres.

My canoe ran ahead of the surveying canoes.  The height of the water made the going easy, for most of the snags and fallen trees were well beneath the surface.  Now and then, however, the swift water hurried us toward ripples that marked ugly spikes of sunken timber, or toward uprooted trees that stretched almost across the stream.  Then the muscles stood out on the backs and arms of the paddlers as stroke on stroke they urged us away from and past the obstacle.  If the leaning or fallen trees were the thorny, slender-stemmed boritana palms, which love the wet, they were often, although plunged beneath the river, in full and vigorous growth, their stems curving upward, and their frond-crowned tops shaken by the rushing water.  It was interesting work, for no civilized man, no white man, had ever gone down or up this river or seen the country through which we were passing.  The lofty and matted forest rose like a green wall on either hand.  The trees were stately and beautiful.  The looped and twisted vines hung from them like great ropes.  Masses of epiphytes grew both on the dead trees and the living; some had huge leaves like elephants’ ears.  Now and then fragrant scents were blown to us from flowers on the banks.  There were not many birds, and for the most part the forest was silent; rarely we heard strange calls from the depths of the woods, or saw a cormorant or ibis.

My canoe ran only a couple of hours.  Then we halted to wait for the others.  After a couple of hours more, as the surveyors had not turned up, we landed and made camp at a spot where the bank rose sharply for a hundred yards to a level stretch of ground.  Our canoes were moored to trees.  The axemen cleared a space for the tents; they were pitched, the baggage was brought up, and fires were kindled.  The woods were almost soundless.  Through them ran old tapir trails, but there was no fresh sign.  Before nightfall the surveyors arrived.