ICEBERGS IN NAVIGATION BARNES. 



735 



APPENDIX 1. 



Letter from Prop. Barnes to '"Nature," on the rise op temperature 

 associated with the melting op icebergs. 



[Letter to Nature, ijublishej in the issue of Dec. 12, 1913.] 



During the summer of 1912 I had an opportunity of examining in detail the tem- 

 perature effects of icebergs. The Canadian Government placed its steamship Mont- 

 calm at my disposal for the tests, and three weeks were spent through the Strait of 

 Belle Isle. Careful records were made of the temperature effects of icebergs and land. 

 These tests have shown conclusively that it is the rise of temperature which is the 

 direct action of the melting iceberg, and that when a fall of temperature is observed 

 near ice it is due to the action of a coldec current in which the iceberg is floating, and 

 is not due to the cooling influence of the ice. Cooler currents may exist throughout 



Fig. 9.— Isothermal lines around iceberg. 



the Arctic current, whether accompanied by ice or not, but the presence of the ice 

 causes a zone of warmer water to accumulate for a considerable distance about it. 



The icebergs I studied in the Strait of Belle Isle and off the eastern end of the 

 strait in the Labrador current showed no appreciable cooling, even within a few 

 yards of them. The rise of temperature approaching an isolated berg was somewhat 

 over 2° C. In figure 9 I show the isothermal lines about a typical berg off the eastern 

 end of the Strait of Belle' Isle. This diagram was obtained by arranging a number 

 of courses for the ship from all sides up to a radius of 6 miles. 



As a good illustration of how icebergs and groups of icebergs affect the water tem- 

 perature I show a microthermogram in figure 10, taken from the records made passing 

 westward through the Strait of Belle Isle. In every case the approach to ice caused 

 a rise of temperature. 



