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1-02601, in lat. 3° 8' N., and on the boundary line
between the equatorial and Guinea currents. The
same low specific gravity was observed in following
the equatorial current as far as St. Paul’s rocks”
after Avhich it quickly rose as the Brazilian coast was
approached; and the maximum of 1-02786 was
ohtained on the 26th September, when off the
entrance to Bahia, in latitude 13° 4' S.
^ The observations in tbe Soutb Atlantic were
bmited to a line doAvn tbe western side as far as tbe
Abrolbos Bank, and tbence across to tbe Cape of
Good Hope. In tbe region of tbe south-east trade-
Avirid, therefore, we have only a few observations
close to the coast; and as we have seen in the North
Atlantic, on the voyage from Teneriffe to St. Thomas’s,
the specific gravity is higher in mid-ocean than either
on the east or the Avest side, so in the South Atlantic
it is possible tbat tbe same may bold good. Prom
tbe Abrolbos Bank to Tristan d’Acunba tbe specific
gravity sinks steadily from 1 ‘02785 to 1-02606, and
tiom Tristan to tbe Cape of Good Hope, along a
course lying between tbe 35tb and tbe 37tb parallels
of soutb latitude, tbe mean specific gravity was
1-02624. Between the same parallels of north latitude
tbe mean specific gravity Avas 1-02713.
It must be remembered that the results obtained
can only be held good for tbe season of tbe year in
Avbich tbey Avere observed, and tbat tbe observations
in diflerent latitudes were made in different seasons,
and, further, that all the observations north of the
line as far as 20° N. were ohtained on the eastern side,
and those to the soutliAvard of it as far as 30° S. were
ohtained on tbe western side of the ocean; so tbat
it Avould be unwise to attempt to draw any general
conclusions from sucb imperfect data. Considering,
however, our four parallel sections, avc bave at least
this positive result—tbat in the month of June and
mean latitude 36° N. the surface-Avater in mid-ocean
has a mean specific gravity of 1-02712, that in the
months of Pehruary and March and mean latitude
22° N, the mean surface specific gravity is 1 02773,
that in the month of August and mean latitude 2° N.
it is 1-02624, and that in the month of October in
mean latitude 36' S. it is 1-02621.
On the way to and from Halifax in the month of
May some observations Avere obtained iu tbe cold
Avater with wbicb the north-eastern coast of America
is surrounded, the mean specific gravity being
1-02463. On tbe 1st May in the Gulf-stream the
specific gravity of the Avater was 1-02675, and its
temperature 23°-9 C .; and the next day it was
1-02538, and the temperature 13°-3 C. If the results
he reduced to their values at the respective temperatures
of the different waters, Ave have for the specific
gravity of the Gulf-stream Avater 1-02445, and of
Labrador-current Avater 1-02584 ; so tbat tbe fall of
temperature very much more than counterbalances
the want of salt in the Avater. In the same way Ave
find the mean specific gravity of the Avater referred to
the temperature which it has in the ocean to he—in
latitude 36° N. and month of June 1-02548, in 22° N.
and month of Pehruary and March 1‘02592, in 2° N.
and month of August 1-02335, and in 36° S. and
month of October 1-02659.
Prom the determination of the specific gravity of
intermediate and bottom-Avater, Mr. Buchanan con