to be an excellent place for my researches. In a marsh by the side of the river, I collected specimens of an _Isoetes_, which does not appear to differ from the one (_Isoetes lacustris_, Linn.) which grows in Great Britain. The sight of this plant recalled pleasing recollections of long past times, and I could not refrain from indulging in a lengthened train of reflections, which ended by comparing it with myself—a stranger in a strange land, and associated with still stranger companions. Our next journey, which was one of four long leagues, through an arid, undulating, sandy, thinly-wooded country, brought us to the foot of the Chapada da Mangabeira, an elevated level table-land, nearly forty miles broad. On this journey we were dreadfully scorched by a burning sun; not a breath of wind was to be felt, and we all suffered very much from thirst, as not a drop of water was to be met with, and the men had neglected to fill the large leathern bag (boracho) before we started. Shortly after leaving Oeiras, I was obliged to provide myself with one of these necessary articles; it held about two gallons, and when full, was carried between the two side loads of one of the horses. We encamped beneath a large Piki tree, not far from a spring of cool clear water which emptied itself into a large morass. As this is the last watering-place to be met with till the Chapada is crossed, the usual way of proceeding is to leave it about mid-day, and push on without stopping till half of the distance has been performed; and by leaving again early on the following morning, the next watering-place may be gained in the forenoon.