Page:Polar Exploration - Bruce - 1911.djvu/189

Rh, as the results of the observations of this and the other expeditions have not yet been fully investigated.

On board the Challenger Buchanan ascertained that this exceptionally cold bottom water near the coast of South America had a very high density, and this was confirmed by the observations of the Gazelle. "It is this density at constant temperature which decides whether a water can carry its surface temperature down to great depths, or whether it shall remain at the surface, and it is the annual range of temperature of such water which gives it its penetrating power" (Proc. Royal Society, 1875, vol. clvii).

I have specially referred to this cold water at the bottom of the deep waters of the Atlantic Ocean off the South American coast as an example of the intimate connection of Antarctic phenomena with those of other parts of the world, for here the interesting question arises, How far does this cold Antarctic water flowing northward at the bottom of the Atlantic Ocean (if the conclusion is correct on the evidence we have at our disposal) not only affect the temperature, salinity and oxygenation of the waters of the Atlantic Ocean, but also, how far does it bring with it forms of Antarctic animal life, which help to populate the deep waters of the Atlantic