"The _rubia tinctoria_ is found in many of the extensive forests, but the best is in Tarija, the Chaco, and the Sierra de Cordova; it yields a brilliant colour. It was not till within these few years that notice was taken of a new mode of dyeing a green colour from a production called by the Spaniards _clavillo_, from its resemblance to a little nail. Some persons consider it to be the excrement of a certain insect smaller than the cochineal; others believe it to be the insect itself. Hitherto it has only been gathered in Carquejia, and the point is found introduced into the bark of a shrub; it was first used by the poor people of the country, and it has since been proved by repeated experiments that the Vicuña and Alpaca wools, as well as cotton, after being prepared with astringents, such as alum, and previously boiled in a yellow dye, when thrown into a solution of clavillo, acquire a beautiful green colour; the shade of this simple is in itself greenish, and by keeping grows darker: abundance of it is found in the valley of Catamarca and province of Tucuman, but as yet no scientific experiments have been made with it." A variety of valuable gums and medicinal balsams may be had from Paraguay, of the efficacy of which marvellous stories are related by those who have resided in those regions. The tree producing caoutchouc is found in abundance about the rivers in the upper part of that province, where the Indians have long known its value, and use it as a substitute for candles: the children make balls of it to play with. They obtain it by making an incision in the tree, from which the gum is run into a hide placed beneath to catch it, and when cold is wound upon large balls for use. In addition to these, I may mention nitrate of soda, so much used now in our cotton manufactories, which may be procured in any quantity from the provinces of La Plata;--as yet, I believe, not a single bag of it has ever been brought from Buenos Ayres, although there is no reason why it should not be imported from thence at as low a cost as from Chile and Peru; from which countries alone, of late years, the annual importations have been from 50,000 to 100,000 cwt. War in Europe will always create an increased demand for the produce of such a country as Buenos Ayres. In the last years of the general war, not only was there an enormous demand for the hides of Buenos Ayres, but considerable quantities of tallow also were shipped from thence; and, although those shipments ceased to answer when the Russian markets were reopened, they may always be calculated upon again should any stoppage take place of our ordinary supplies through the Baltic. At present, though Buenos Ayrean tallow is worth as much as Russian in the English markets, there is no great quantity of it produced, in consequence of the animals being killed for their hides as soon as they are marketable, which is before they yield tallow in any quantity worth collecting.