Reflections following the visit to the Galapagos (6)
The currents about these islands are very remarkable, for in addition to their velocity, which is from two to five miles an hour, and usually towards the north-west, there is such a surprising difference in the temperature of bodies of water moving within a few miles of each other, that this subject must be reserved for further discussion. On one side of an island (Albemarle Island) we found the temperature of the sea, a foot below the surface, 80°. Faht.; but at the other side it was less than 60°. In brief, those striking differences may be owing to the cool current which comes from the southward along the coasts of Peru and Chile, and at the Galapagos encounters a far warmer body of water moving from the bay of Panama, a sort of 'gulf stream.' The retentive manner in which such ocean rivers preserve their temperature has been frequently remarked: and must have a great effect upon the climates of countries near whose shores they flow.