The Paraguay, properly so called, on the contrary, may be passed up by vessels of some burthen the whole way[52] to the Jaurú, in latitude 16° 25´, presenting the extraordinary extent of an uninterrupted inland navigation of nearly nineteen degrees of latitude, calculating the straight distance north and south, throughout the whole of which there is not a rock or stone to impede the passage, the bottom being everywhere of clay or fine sand. The least depth of water is in the channels through the delta by which it discharges itself into the Plata, but in the passage called the Guazú (the great canal) there is seldom less than two and a half fathoms.
The upper part of the river is extremely picturesque, and its shores abound in all the varieties of an intertropical vegetation. The palms particularly are remarkable for the magnificence of their growth. Below the junction of the Paranã it is thickly studded with islands covered with wild orange-trees, and a variety of beautiful shrubs and parasitical plants, new to European eyes.
It has been remarked that there is a great resemblance in the periodical risings and inundations of the Paraguay and those of the Nile, and there is certainly a striking analogy between the two rivers in many respects. Both rise in the torrid zone, nearly at the same distance from the equator, and both, though holding their courses towards opposite poles, disembogue by deltas in about the same latitude; both are navigable for very long distances, and both have their periodical risings, bursting over their natural bounds, and inundating immense tracts of country.
The Paranã begins to rise about the end of December, which is soon after the commencement of the rainy season in the countries situated between the tropic of Capricorn and the equator, and increases gradually till the month of April, when it begins to fall something more rapidly until the month of July. There is afterwards a second rising, called by the natives the _repunte_; but this, though regular, is of no great consequence, the river never overflowing its banks. It is probably occasioned by the swelling of the rivers from the winter rains in the temperate zone.
The extent of these periodical risings is, of course, in some degree, regulated by the quantity, more or less, of rain which may fall during the corresponding season; but, in general, the inundation takes place with great regularity, the waters rising gradually about twelve feet in the bed of the river in four months; this is the ordinary average of the increase of the river after its junction with the Paraguay; though above it, at Assumption, where the river is much confined, the rise is said to be sometimes as much as five or six fathoms.