liU2] 0)1 Tfcbergs and their Location in Navigation. h?*?) 



room. This method is dcsh'able on a fust moving ship or in regions 

 wiiere nmcli floating ice is about. 



It will 1)0 seen that tlie micro-thermometer is a refined electrical 

 resistance thermometer. 



Peactical Tests of the Micro-thermometer. 



Realizing the great menace to navigation in the presence of 

 ice, I was anxious to find whether refined measurements of the 

 temperature of the sea could be used to warn a ship at night or in 

 time of fog. 



As a preliminary test of the sensitiveness of the instrument, I 

 had some experiments made in the St. Lawrence river during the 

 time of the ice-breaking work. The C. Gr. S. " Lady Glrey," having 

 cleared out the ice from the channel as far as Lake St. Peter, from 

 Quebec, was detailed to steam slowly up the river towards the 

 unbroken ice sheet in the lake. The edge of the ice was sharp 

 and well defined, and extended out from the shore along the banks of 

 the river. The current of the river flowed from under the ice in a 

 shghtly diagonal direction, so that, steaming in the open water, the 

 current flowed in such a way as to pass under the edge of the shore 

 ice. The ship started two miles below the upper edge of the ice, and 

 measurements of temperature were taken at intervals up to the ice. 

 Fig. 8 shows the character of the temperature curve obtained, and 

 illustrates how accurately the micro-thermometer registers even so 

 small a temperature change as one-tenth of a degree per mile. In 

 the lower part of the diagram a map is shown giving the edge 

 of the ice, the ship's course, and the direction of the current. It 

 will be seen that the temperature is everywhere a measure of the 

 ship's distance from the ice sheet taken along the current lines. 

 Thus the temperature curve gives us the contour of the ice. 



Having so determined the presence of the ice sheet, even in water 

 less than one-tenth of a degree above the freezing point, I determined 

 to obtain measurements of the sea temperature in the vicinity of 

 icebergs. In July 1910, the Canadian Department of Marine and 

 Fisheries kindly granted me facilities for doing this on the ice-break- 

 ing steamer " Stanley," proceeding to Hudson Bay with a survey 

 party. My assistant, Mr. L. V. King, undertook the observations 

 during this trip, and an account of the work was published in my 

 report to the Government. 



The thermometer was placed over the side of the ship, immersed 

 to a depth of about five feet, and a record of temperature was made 

 through the Straits of Belle Isle along the Labrador coast to Hudson 

 Bay. The recorder was placed in Mr. King's cabin, where he could 

 observe the effect of ice and land. Several icebergs were passed in 

 the northern journey at a distance of about half a mile, and these 

 were recorded on the chart by a rapid fall of temperature of from one 



'2 ^ ^2. 



