EXPERIMENTS IN HERDING SEALS. 



421 



AUGUST 18. 



HEEDING- SEALS. 



An experiment was made this morning with a view to determining the effect on 

 the temperature of the water in a pond or lake produced by herding a body of seals 

 in it. Three hundred and fifty seals were driven from Lukanin, where 900 seals were 

 driven from yesterday afternoon, and held four hours in the little pond beside Ice House 

 Lake. The temperature of the pond before the seals were put in was 50° at the border 

 and 1° lower in the middle. The pond is shallow, having an average depth of only 2 J 

 feet. The seals "w«Te pui^Jji .at 10.35. Below is a record of observations made with a 

 common mercury thermometer : 



Time. 



"Weather. 



Air. 



Pond temperature. 



10.30 

 10.45 

 II 



11.15 

 11.30 

 11.40 

 12 



12.15 

 12.30 

 12.45 

 1 



1.15 

 1.30 

 1.45 

 2 



2.15 

 2.45 



Clear 



Sunshine and light fog 



Light fog 



.-...do 



Sunshine and fog 



Sunsliine and fog; light breeze. 



Fog and light breeze 



do 



Fog and breeze 



do 



Thick fog and light breeze 



do 



Thick fog 



Light fog 



do 



Thick fog 



do 



On two occasions the temperature of a cove occupied by seals for half an hour 

 was taken separately and found to be 1° higher than the open water. The 

 temperature of Ice House Lake at 12.45 and 2.10 was 52°, the same as that of the 

 jiond in which the seals were. The last five observations were made by Mr. Clark ; 

 the others were made by Mr. Townsend. Mr. Clark's air temperatures were taken 

 with the thermometer wet and in the wind; Mr. Townsend's were taken in the shelter 

 of the long grass. 



The pond adjacent to the one in which the seals were held and larger in extent 

 did not show any remarkable difference of temi)ei ature. Both ponds were sheltered 

 among the hills^, and the gradual increase of temperature from 50° to 53° may have 

 been due to the effects of the sun as noon was approached. The pond was about half 

 an acre in extent. It is evident from this experiment that Webster Lake, Lake 

 Antony and certain of the ponds about Poloviua could be utilized for holding the 

 bachelors from these rookeries. The salt lagoon is conveniently located for all the 

 rookeries of the southern end of the islands, and if need be those from Zapadni and 

 Polovina could be driven there. 



At 3 o'clock the seals were driven over and turned iuto the lagoon. Tbey swam 

 down through the length of the lagoon and crossed over the neck at the point which 

 is the usual exit of the rejected seals turned out from the killings at Ice House Lake. 



