Before the independence of Brazil, the Portuguese government had a factory at the mouth of the Paduarí, one of the tributaries of the Rio Negro, for the purpose of making these cables for the use of the Pará arsenal, and as a government monopoly. Till within these few years the fibre was all manufactured into cordage on the spot, but it is now taken down in long conical bundles for exportation from Pará to England, where it is generally used for street sweeping and house brooms, and will probably soon be applied to many other purposes. It is cut with knives by men, women and children, from the upper part of the younger trees, so as to secure the freshest fibres, the taller trees which have only the old and half-rotten portion within reach, being left untouched. It is said to grow again in five or six years, the fibres being produced at the bases of the new leaves. The trees are much infested by venomous snakes, a species of _Craspedocephalus_, and the Indians are not unfrequently bitten by them when at work, and sometimes with fatal consequences. The distribution of this tree is very peculiar. It grows in swampy or partially flooded lands on the banks of black-water rivers. It is first found on the river Padauarí, a tributary of the Rio Negro on its northern side, about 400 miles above Barra, but whose waters are not so black as those of the Rio Negro. The Piassaba is found from near the mouth to more than a hundred miles up, where it ceases. On the banks of the Rio Negro itself not a tree is to be seen. The next river, the Darahá, also contains some. The next two, the Maravihá and Cababurís, are white-water rivers, and have no Piassaba. On the S. bank, though all the rivers are black-water, there is no Piassaba till we reach the Marié, not far below St. Gabriel. Here it is extensively cut for about a hundred miles up, but there is still none immediately at the mouth or on the banks of the Rio Negro. The next rivers, the Curicuríarí, the great river Uaupés, and the Isánna, though all black-water, have none; while further on, in the Xié, it again appears. On entering Venezuela it is found near the banks of the Rio Negro, and is abundant all up to its sources, and in the Témi and Atabápo, black-water tributaries of the Orinoco. This seems to be its northern limit, and I cannot hear of its again appearing in any part of the Amazon or Orinoco or their tributaries. It is thus entirely restricted to a district about 300 miles from N. to S. and an equal distance from E. to W. I am enabled so exactly to mark out its range, from having resided more than two years in various parts of the Rio Negro, among people whose principal occupation consisted in obtaining the fibrous covering of this tree, and from whom no locality for it can have remained undiscovered, assisted as they are by the Indians, whose home is the forest, and who are almost as well acquainted with its trackless depths as we are with the well-beaten roads of our own island.