EXPEDITION TO POINT I'.AKRDW, ALASKA. 



337 



SKA-ICE TEMPERATURE. 



On November 13, 1882, a wooden box, about (i indies square on the bottom, with a sliding 

 rover, was placed in an excavation about I indies deep made in the sea-ice about 50 yards 

 from the shore. In this a spirit thermometer (Xo. GS4) was set upright, and the bottom of the 

 box tilled with sea water, which immediately froze, so as to inclose, the, bulb of the thermometer 

 in iee. 



A break in the ice wear the shore occurred on the night of >>"<,> ember 20, and the ice moved 

 jHwa.y, carrying the thermometer with it. Spirit thermometer No. 713 was exposed in a similar box 

 in December 10, 1882, and was kept in place till June 0, 1883, when the ice was beginning to melt 

 in the surface. These thermometers were read every day about local noon. 



The ice formed to the depth of 5^ feet, and while the temperature of the water immediately 

 beneath it continued practically constant at about 29 F., the ice showed considerable variation. 

 When the temperature of the air was low, the temperature of the ice was, as a rule, higher than 

 that of the air. The reverse was true, as a rule, when the weather grew warmer. 



TEMPERATURE OF THE SEA. 



From November 11, 1881, till May 7. 1883, the temperature of the sea- water was observed once 

 51 day, from 12 m. to 2 p. in., local time, and hourly from May 7 to the end of the voyage home. 

 It was taken at the surface and bottom iu 17 feet of water, about 100 yards from the shore, through 

 a hole iu the ice in the winter, and by rowing out in a small boat when the water was open. The 

 surface temperature only was taken from the vessel. 



The temperature of the water in the various fresh and brackish lagoons was taken from time 

 to time during the winter, and although ice was formed upwards of 6* feet thick, leaving scarcely 

 any water underneath it, unfrozen mud was found at the bottom. 



nhowiiig the sea-ice temperature at TJglnamie from JVojvw/w, 1882, to ./., 1SS:>. 



[Observations taken at noon, local time; water temperature taken on bottom, IT !'<<> dtcji, one-eighth mile from slmro.) 



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