December 12, 1912] 



NATURE 



409 



be detected even right beside the berg. 1 took a 

 number of samples of sea water at different distances 

 from the berg, as well as from places far from ice. 



stances, and there is no reason to doubt their correct- 

 ness. Their comparison shows no dilution due to the 

 icebergs, which goes to show how quickly the melted 



These samples I carefully bottled and brought home 

 to the laboratory, where they were most accurately 

 tested by the electric conductivity method in our 





water from the berg is mixed with the sea water. 

 Larger variations were found over different parts of 

 the sea than were obtained in the proximity of ice. 



My tests have shown that an iceberg probably causes 

 only two of the Pettersson currents, i.e. a cold current 

 sinking downwards carrying with it all the melted 

 ice water, and a horizontal surface current of sea 

 water flowing in towards the ice to cause its melting 

 (see Fig. 3). By this means we should expect the 

 sea in the immediate proximity of icebergs to be 

 warmer than further awav, because the sea surface 



Fic. 2.— Microthermogram through the Straits of Belle Isle, showing the 

 rise of temperature caused by ice. 



physico-chemical department by Dr. Mcintosh and 

 -Mr. Otto Maass. The tests were carried out at a 

 constant temperature in the most favourable circum- 

 NO. 2250, VOL. 90] 



current is moving inwards towards the berg, and does 

 not share in the normal vertical circulation which 

 tends to keep the sea surface temperature cooler. 



It is interesting to find that an iceberg causes its 

 own current of warmer water, thus providing for its 

 own destruction. Abundant evidence is at hand to 

 show the melting process going on under the water- 

 line. 



Dissolved .'lir. 



In my observations of icebergs I was greatly struck 

 with the large amount of dissolved air in the ice 



