1912] on Icebergs and their Location in Navigation. 535 



to two degrees as the bergs were approached. It was found as the 

 ship drew near a berg that a rise of temperature took place first, 

 followed by a rapid fall. On the micro -thermometer the effect was 

 clearly shown, but would have been missed entirely on an ordinary 

 thermometer, I have called this peculiar rise and fall of temperature 

 the Iceberg Effect. And it seems to be characteristic, and easily 

 distinguished from the small oscillations of temperature found in the 

 open sea. It is evident that the iceberg effect is caused by the fresh 

 water observed by Pettersson in his tank experiments diluting the 

 sea water, and creating a blanket of lighter water in which the sun's 

 heat is absorbed. In the open sea the warming of the sea by the 

 sun is offset by the vertical circulation, but in the fresher and lighter 

 water this is impossible, and the warmer water remains on the surface. 



Disturbing Influence of Land on the Temperature 

 OF the Sea. 



One of the most interesting results of the Hudson Bay experiments 

 was the effect of land on the temperature of the sea. The coast 

 of Labrador appears to exert an influence in turning up the colder 

 undercurrents of the Arctic stream. Thus, whenever the ship 

 steamed in towards the coast line the temperature was found to fall 

 one or two degrees. The limit of the influence appears to be about 

 five miles. It has been shown by Dr. Dawson that the shoals in 

 the Bay of Fundy influence the surface temperatures, and this is 

 in accord with the present results. Taking this into consideration, it 

 appears that the micro-thermometer may be of great service in telling 

 the presence of land and shoals from a ship at sea. Fig 4 shows 

 the effect of the coast line of Labrador in lowering the surface tem- 

 perature of the sea. 



Transatlantic Experiments. 



During my trip across the Atlantic early in May of this year, I 

 obtained a continuous record of the temperature of the sea from 

 Halifax to Bristol. Through the kindness of the Canadian Northern 

 Steamship Company, I installed the micro-thermometer on the 

 " Royal George," and for 3000 miles the instrument faithfully re- 

 corded the temperature variations in the sea. In these experiments 

 the bulb of the thermometer was placed in sea water, drawn con- 

 tinuously from the circulating water of the engines at a point within a 

 few feet of the intake mouth situated about 16 feet below the water 

 line. The wires passed through the engine room to Chief Engineer 

 McQuitty's office, where the recorder was situated. The course 

 followed was south of Cape Race to the south of Ireland. 



