The universal geography : earth and its inhabitants

6
WEST AFRICA.
expedition ill u purt of the Azorian Atlantic presenting great inequaUties of deptt,
and where four soundings revealed 500, 95, 150, and 830 fathoms in rapid
succession. J,'everthelcss, the same naturalists observed that tlie ^vatcr was of a
sea-green colour between the Canaries and Cape Verd group, where, instead of
meeting with comparatively shallow water, they determined a mean depth of uo
to 3,300
Feet.
pi,r. 2. Deittus of the AzomAH Atlantic.
Depths.
3,300 to 1G,600
feet.
Scale 1 : 40,000,000.
^'jp;! VltJ [sJos s
*West or Gree^w'C^>
10,500 Feet and
upwards.
. 600
to 3,300
Feet.
Mfles.
Heights.
3,300 Feet and
upwards.
less than 1,500 fathoms. In fact, this phenomenon of shifting colours in sea-
wutor has been explained by physicists in the most diverse ways. While Toyubee
asserts tliat a green tint prevails when the surface is cool and the atmosphere
moist, the observations of the Gazelle would seem to show that the contrast
between blue and greenish hues is due to the different degrees of salt held in
solution, blue water being the most dense.