530 Professor Howard T. Barnes [May 31, 



by the plough-like action of a vessel's bow going at speed. Under 

 these circumstances the hydrometer would be no better than the 

 thermometer. 



" Again, it is well known that about the Bauks the Labrador 

 current is sometimes colder when no ice is to be seen than it is when 

 the contrary is the case. In winter its surface temperature even 

 falls to 28° F. Large icebergs have been actually passed at a 

 distance of a quarter of a mile, and the sea-surface temperature 

 tested carefully, without finding a single degree of difference from 

 what previously existed when there were none in sight. 



" It may be fairly assumed, therefore, that no reliance is to be 

 placed upon the thermometer as an immediate or direct means of 

 detecting the presence of ice, especially when it takes the form of 

 stray bergs. In fog it will simply tell you when the ship has entered 

 the cool current, which may, or may not, he ice-bearing." 



Dr. W. Bell Dawson, Director of the Canadian Hydrographic 

 Survey, has made a study of the temperature effect of an iceberg in 

 the Straits of Belle Isle. In his report to the Department of 

 Marine and Fisheries, in 1907, he says : — 



" Icebergs in Relatioti to Water Temperature. — On August 7, 

 1894, an unusually large iceberg was aground in 57 fathoms off 

 Chateau Bay. An instrumental survey made in a boat showed it to be 

 780 feet long, 290 feet wide, and 105 feet high. The water tempera- 

 tures on different sides were 38°, 37°, and 37°, at distances ranging 

 from 130 to 1320 feet from it. On that day the water temperature, 

 on a line from Chateau Bay to Belle Isle, was 36^° off the mouth of 

 the bay, 39° in the middle, and 41'^ off the south end of Belle Isle. 

 It was lowered less than 2°, therefore, in the proximity of the iceberg. 



" The next day, August 8, a small iceberg was aground in Chateau 

 Bay. The water temperature in the middle of the bay was 34° and 

 at the mouth 34|°. The lowest temperature close to the iceberg was 

 33^°, which shows a difference of not more than 1° due to the iceberg. 



" In 1906, an iceberg about 140 feet long was aground in 38 

 fathoms, about 1^ mile from Station P, where it remained for 

 several days. On June 19 it was examined in a boat. The surface 

 temperature in the strait at the time was 35^°, and close around the 

 berg it was found to be the same, except on the west side, where the 

 water tailing from it with the flood was 35°. There was thus only ^'^ 

 difference of temperature to be found near it." 



It is clear that up to the time of the experiments with the micro- 

 thermometer, in 1910, there was good evidence to show that the 

 ordinary thermometer is useless to detect the small temperature 

 effect of an iceberg. Hence captains are correct in their statement 

 that the ship's thermometer is useless as a means for locating an 

 iceberir. 



