The Influence of Icebergs on the Temperature of the Sea

Abstract

PROF. BARNES, in NATURE of February 20, gives an important piece of information which seems to me to enable us to clear up the confusion at present surrounding this subject, as it explains the reason for the different results obtained by Prof. Barnes in his earlier and later observations, and why his results differ from those of previous observers; and it also helps us to an explanation of the puzzle of the rising temperature of the sea on approaching icebergs, found by Prof. Barnes. The earlier observers made their tests in the cold but weak sea-water floating on the surface. Prof. Barnes's first tests were made at a depth of 5 ft. The first part of his curve, Fig. 1 (NATURE, June 20, 1912), gives the temperatures of the sea as the thermometer passed under the outer edge of the cold surface water, and was thus made in the ordinary sea-water, and gave the temperatures below the cold surface water, until the ship arrived within a mile of the iceberg, where the increasing depth of the cold surface water began to affect the thermometer, and from that distance, the thermometer being now in the cold surface water, the temperature fell rapidly as the ice was approached. The thermometer in Prof. Barnes's second ship, he tells us in his last letter, was placed at a depth of 18 ft. below the surface, and seems to have been always too deep to get into the cold surface water.