for leaves at a distance, proved to be thickly crowded bracteas. The appearance was altogether different, in the purity and freshness of the colour, from the autumnal tints which, in many of our forest trees, adorn the woods of the temperate zone at the season of the fall of the leaf. A single species of the South African family of Proteaceæ, Rhopala ferruginea, descends here from the cold heights of the Paramo de Yamoca to the hot plain of Chamaya. We often found here the Porlieria hygrometrica (belonging to the Zygophylleæ), which, by the closing of the leaflets of its finely pinnated foliage, foretels an impending change of weather, and especially the approach of rain, much better than any of the Mimosaceæ. It very rarely deceived us.
We found at Chamaya rafts (balsas) in readiness to convey us to Tomependa, which we desired to visit for the purpose of determining the difference of longitude between Quito and the mouth of the Chinchipe (a determination of some importance to the geography of South America on account of an old observation of La Condamine).[10] We slept as usual under the open sky on the sandy shore (Playa de Guayanchi) at the confluence of the Rio de Chamaya with the Amazons. The next day we embarked on the latter river, and descended it to the Cataracts and Narrows (Pongo in the Quichua language, from puncu, door or gate) of Rentema, where rocks of coarse-grained sandstone (conglomerate) rise like towers, and form a rocky dam across the river. I measured a base line on the flat and sandy shore, and found that at Tomependa the afterwards mighty River of the Amazons is only a little above 1386 English feet across. In the celebrated River Narrow or Pongo of Manseritche,
