THE SPRING AND SUMMER OF i8g4 463 



adding to this the 2 feet which tlie Fram is raised up 

 above the ice, there is no small distance between her and 

 the water." 



The temperature on the ice in summer is about thaw- 

 ing-point, but gradually as the winter cold comes on, it, 

 of course, falls rapidly on the surface, whence the cold 

 slowly penetrates deeper and deeper down towards the 

 lower surface, where it naturally keeps at an even temper- 

 ature with the underlying water. Observations of the 

 temperature of the ice in its different layers were con- 

 stantly taken in order to ascertain how quickly this cool- 

 ing-down process of the ice took place during the winter, 

 and also how the temperature rose again towards spring. 

 The lowest temperature of the ice occurred in March and 

 the beginning of April, when at 1.2 metres it was about 

 3.20 Fahr. (—16 C), and at 0.8 metre about 22' Fahr. 

 below zero ( — 30' C). After the beginning of April it 

 began to rise slowly. 



At these low temperatures the ice became very hard 

 and brittle, and was readily cracked or broken up by a 

 blow or by packing. In the summer, on the other hand, 

 when its temperature was near melting-point, the ice 

 became tough and plastic, and was not so readily broken 

 up under packing. This difference between the condition 

 of the ice in summer and winter was apparent also to the 

 ear, as the ice-packing in winter was always accompanied 

 by the frequently mentioned loud noises, while the pack- 

 ing of the tough summer ice was almost noiseless, so that 



