The road to the baths is very bad, and, above all, the declivities are so; for the number of stones and narrow windings render it in the highest degree disagreeable, to which the dull uniformity of the landscape also contributes. To the right, all that presents itself to the traveller’s view is the lofty volcano, the contiguous hills being denuded of every blade of vegetation except the cactus Peruvianus, of melancholy aspect, seen here and there along the surrounding slopes; and, if he turn his eye to the left, he looks upon sterile plains cut up by mountain torrents, or a group of hills perfectly arid, of greater or less elevation, and in parts covered with white sand. The analysis of the waters of Yura was attempted by the celebrated naturalist Haenk in the year ’96; but, this philosopher not having ascertained their constituent parts, I have now the honour of presenting to the public the result of my investigations regarding these waters, and several others which are used by the inhabitants of the city. In the narrow glen of Yura there are two situations in which springs of thermal water present themselves, and the one is distant from the other about one hundred and fifty yards. The first, called _agua de hierro_, or ferruginous water, is on the left-hand side of the road as we come from the Calera; and those springs which are higher up are denominated _agua de azufre_, or sulphurous water. I will begin by giving an account of the _agua de hierro_. THE FERRUGINOUS WATER.