The Geographical Journal (Journal of the Royal Geographical Society): Volume XII, No. 2 [‎265r] (32/154)

OCEAN, AND ITS RELATION TO OTHER OCEANOGRAPHICAL PHENOMENA. 12JI
a range from about 28° to about 50° Fahr., though not exceeding 10°
Fahr. in any single 2° square.
The tropical band of small range (less than 10° Fahr.) marks out
approximately the coral-reef regions of the world. It forms an almost
continuous belt around the globe, being broken only by the interposition
of the continental masses, and for a short distance in the Pacific, off the
shores of Central America. Future observations may show it to be
completely broken also otf the western coast of Africa, where it is now
shown as continuous across the whole Atlantic. The Pacific area is the
largest, stretching from near the Central American coast across to the
East Indian seas and Barrier Reef of Australia (and passing through
the Arafura sea into the Indian ocean), confined almost entirely within
the tropics of Cancer and Capricorn, but extending beyond the latter
tropic in the Central South Pacific. The observations within this-
Pacific tropical area show a range from 70° to 90° Fahr., though not
exceeding 10° Fahr. in any single 2° square; throughout the area,
however, a great many of the squares are blank, and future observations
may alter the form considerably.
In the Indian ocean a belt of small range (less than 10° Fahr.)
stretches across from the east coast of Africa (south of Cape Guardafui
and north of Madagascar) to the shores of the Malay peninsula and
Sumatra (and passing through the Arafura sea into the Pacific), lying
mostly to the north of lat. 10 S., and filling up the greater part of the
Arabian sea and of the Bay of Bengal. The observations within this
Indian ocean tropical area show a range from 72° to 87° Fahr.
In the Atlantic the belt of small range (less than 10° Fahr.) extends
across from the Caribbean sea and the north-east coast of South America
to the Liberian coast of Africa, reaching northward in the central part
of the ocean to the northern tropic, and southward to a little beyond
lat. 20° S. The observations within this Atlantic tropical area show a
range from 72 3 to 85 Fahr. It includes three squares, in which the
recorded range just reaches 10° Fahr., all on the parallel of 10° N.
If we now turn our attention to those portions of the map which are
coloured blue, where the range exceeds 10° Fahr., it will be observed
that'the area with a range of temperature between 10° and 20° Fahr.
(indicated by the palest shade of blue) is the most extensive on the
surface of the ocean. It fills up the intervals between the three bauds
of small range just described, and encloses in certain positions areas
having a greater range. The line of 15° range cuts this pale blue area
into two parts, and it will be observed that the area with an annual
range exceeding 15° Fahr. lies mostly in the temperate regions between
the tropics and the polar circles. The area does not reach the antarctic
circle in the south, but it penetrates considerably beyond the arctic
circle in the North Atlantic, extending north of the island of Jan Mayen,
and in Bering strait it extends just beyond the arctic circle. In the