432 Capt. Sabine on the Stream of the River Amazons 
At noon, having advanced considerably within the boundary, 
so that it was no longer in sight from the ship, the specific 
gravity of the surface water was 1°0185, and its temperature 
81°8. 
Being desirous of ascertaining the depth at which the water 
of the ocean would be found unmixed with the river-water, 
Dr. Marcet’s very simple and practical apparatus was em- 
ployed to bring up water from fifty fathoms, the specific gra- 
vity of which proved 10262; the bottle was then sent down 
a second time to twenty-one fathoms, at which depth the spe- 
cific gravity was also 10262, limiting the depth of any ad- 
mixture of the fresh water to less than 126 feet. Its super- 
ficiality was further evinced by the colour of the water in the 
ship’s wake, which was much more blue than that of the 
general surface. The temperature of the water from fifty 
fathoms was 77°°2, and from twenty-one fathoms, 80°°5; we 
had no bottom with 105 fathoms. 
From noon on the 9th, till 10 A.M. on the 10th, we had 
found the current of the ocean running with an average velo- 
city of four knots in a direction N. 54° W.; the ship’s true 
course had been very nearly N. 45° W.; the division line of 
the streams trended about N. 33° W. It was obvious, by the 
general appearance of the respective surfaces, that the current 
of the river-water was running with considerable rapidity in a 
direction inclined to that of the ocean, and nearly coinciding 
with the line which marked their separation; the ship’s course 
was therefore altered a point westerly. During the afternoon 
of the 10th, and morning of the 11th, the colour and specific 
gravity of the surface-water indicated that we continued in the 
river-stream; but that it was becoming latterly more and 
more mixed with the sea-water. At noon, in latitude 7° 01’, 
and longitude 52° 38'°5, the specific gravity was 1:0248, tem- 
perature 81°°5; and from twenty fathoms, 10262. Between 
noon on the 10th, and noon on the 11th, the ship was set 
N. 38° W., sixty-eight miles, or rather less than three miles 
an hour; which may, therefore, be considered the general 
direction and rate at which the water of the Amazon was pro- 
ceeding at the distance of 300 miles and upwards from. its 
natural banks. ‘The original impulse at its discharge into the 
ocean is to the eastward of north; so much, therefore, had its 
course been deflected, by having to sustain the continual pres- 
sure of the current of the ocean on its eastern side. As the 
initial velocity must have greatly exceeded that which it had 
preserved after a course of 300 miles, and as the force of the 
current which presses on it is much less in the neighbour- 
hood of the land, than it subsequently becomes, it is probable 
that 
