THE AMAZON VALLEY. 2S7
A somewhat similar phenomenon is seen at the mouth of the Tapajoz. Here, at the end of the dry season, there is but a small body of water, and the current is very sluggish. The Amazon, however, rises considerably with the tides, and its waters then become higher than those of the Tapajoz, and they therefore enter into that river and force it back ; we then see the Amazon flowing rapidly down, at the same time that the Tapajoz is flowing up.
It seems to be still a disputed question among geographers, whether the Para river is or is not a branch of the Amazon. From my own observation, I am decidedly of opinion that it is not : it appears to me to be merely the outlet of the Tocantins and of numerous other small streams. The canal or channel of Tagipuni, which connects it with the Amazon, and by which all the trade between Para" and the interior is carried on, is one of a complete network of channels, along which the tide ebbs and flows, so as in a great measure to disguise the true direction and velocity of its current. It seems probable that not a drop of Amazon water finds its way by this channel into the Para river, and I ground my opinion upon the following facts.
It is well known, that in a tidal river the ebb-tide will continue longer than the flood, because the stream of the river requires to be overcome, and thus delays the commencement of the flood, while it facilitates that of the ebb. This is very remarkable in all the smaller rivers about Para. Taking this as our guide, we shall be able to ascertain which way the current in the Tagipuru sets, independently of the tide.
On my journey from Para to the Amazon, our canoe could only proceed with the tide, having to wait moored to the bank while it was against us, so that we were of course anxious to find the time of our tedious stoppages diminished. Up to a certain point, we always had to wait more time than we were moving, showing that the current set against us and towards Para; but after passing that point, where there was a bend, and several streams met, we had but a short time to wait, and a long ebb in our favour, showing that the current was with us or towards the Amazon, whereas it would evidently have been different had there been any permanent current flowing from the Amazon through the Tagipuru towards Para.
J therefore look upon the Tagipuru as a channel formed by
