as crossed three hundred Miles from its Mouth. 431 
tabular results, it will be obvious, that by thus nearing the 
land, she quitted the full strength of the stream, and that she 
did not re-enter it again until the day after her departure from 
Maranham, when it was found to be running with the asto- 
nishing rapidity of ninety-nine miles in twenty-four hours. It 
may also be seen, that although in the space comprised be- 
tween the direct course of the stream from Cape St. Roque 
to the West Indies, and the coast of Brazil, the velocity pro- 
gressively diminished on approaching the land, no counter~ 
current was found to take place, but the westerly direction was 
still maintained, though at the reduced rate of less than half 
a mile an hour, when very near the land. It may be attri- 
buted to the rapidity with which the water is thus swept along 
the shore, that no change is perceptible in its temperature, on 
approaching a coast which is so remarkably shallow, as to 
have not more than seventeen fathoms water at thirty-six miles 
in the offing. 
At 10 A.M. on the 10th of September, whilst proceeding 
in the full strength of the current,.exceeding as already noticed 
four knots an hour, a sudden and very great discoloration in 
the surface water a~-head was reported from the mast-head, 
and from the very rapid progress which the ship was making 
was almost immediately afterwards visible from the deck. Her 
position in 5° 08! north latitude, and 50° 28! west longitude, 
both known by observation, sufficiently apprised us that the dis- 
coloured water which we were approaching could be no other 
than the stream of the river Amazon, preserving its original 
impulse at a distance of not less than 300 miles from the 
mouth of the river, and its waters being not yet wholly mingled 
with those of the ocean of greater specific gravity over the 
surface of which it had pursued its course. 
We had just time to secure some of the blue water of the 
ocean for subsequent examination, and to ascertain its tem- 
perature, before we crossed the line of its separation from the 
river-water, the division being as distinctly preserved as if 
they had been different fluids. 
The direction of the line of separation was N.W. by N., 
rather northerly ; great numbers of gelatinous marine animals, 
species of the genus Physalia, were floating on the edge of the 
river-water, and many birds were fishing apparently on both 
sides of the boundary. 
The temperature of the ocean-water was 81°1, and of the 
river-water 81°°8, both within a short distance of the division 
line; the specific gravity of the former was 1:0262, and of the 
latter 1°0204, distilled water being unity: the ocean-water 
had also been found 81° at 7 A.M. on the same morning. 
At 
