Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.2): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

118 WHITE WATER — ICEBEKGS. D^C. • We passed through a space of sea,* many miles in extent, where the water was of a very much lighter colour than usual not of a light-green or muddy hue, such as one sees near land, but of a milky white tint. Being in soundings, one naturally attributed such a change of colour to some peculiarity in the ground ; but I have since thought differently, and am now inclined to believe that the light-coloured water came from a distance, in one of those great, though slow-moving currents, which sweep past the Falkland Islands, and thence northwards : but to what cause its unusual whiteness is to be attributed, I know not. The dissolution of a huge iceberg, or of many ice- bergs, might alter the colour, and certainly would change the temperature of a considerable body of water ; but in this case, a thermometer immersed in the sea did not indicate a degree lower than that of the previous or following day. During the three days, our soundings varied only from fifty to sixty fathoms. The lead certainly brought up fine grey sand while the water was light-coloured, and dark sand at other times but I can hardly think that so decided a change— different from any I noticed elsewhere — could have been caused in fifty fathoms water by so small an alteration in the quality of the bottom. Icebergs have been seen in latitude 40° S., and near the lon- gitude of 50° W' ; perhaps they are sometimes carried nearer the coast, in which case they would ground, and melt away. I suspect that some of the rocks, so often, yet so fruitlessly, sought for — and instead of which many persons have supposed dead whales, wrecks, or large trees, were seen — may have been icebergs, against and upon which sea- weed, drift-wood, or other substances, may have lodged temporarily, causing a rock-like appearance. In this way, perhaps, arose the report of a rock said to have been seen by Lieutenant Burdwood ; of the Aigle and Ariel rocks — and even of those islets sought for ineffec- tually by Weddell, a few degrees eastward of the Falkland Islands.-f- * Lat. 46°.S. Long. 63° W. t On this subject there are a few more remarks, under the head — Cur- rents of the ocean, — in the last chapter but one.