GREENLAND BY THE POLAR SEA 



are very frequent ; during our journey we had onl}- five quite clear days out 

 of the four weeks about the 1st of June. 



The whole of this development has taken place under a temperature of 

 between minus 10° C. and zero. Simultaneously as the temperature becomes 

 positive, about the middle of June, the fog ceases, as the snow is no longer 

 transformed into steam, but begins to flow down the mountain-sides as water. 

 The first running water was observed on the 15th of June, and with that the 

 spring thaw on land had set in in earnest. 



But the ocean-ice still remains in its winter state, covered by a thick layer 

 of loose snow. During the first days of thaw this snow falls together, becom- 

 ing firm and hard, and by Midsummer Day one may still find firm winter going 

 for the sledges on the sea. 



The air becomes increasingly warmer and about the 1st of July the 

 thawing of the ocean-ice commences. It takes place with surprising rapidity. 

 In the morning the snow is still rather firm, in the evening it is soft, and on 

 the next day there is slush in all hollows ; a few days later all the snow has 

 melted, forming pools and lakes on top of the ice. The thaw on the ocean- 

 ice is over in about a week, so that there is only a slight degree of melting in 

 the course of a summer. The water in the lakes on the ice is, of course, 

 0° C, and the low sun is only able to melt the snow where it shines directly 

 on it. As we all know, a certain amount of heat is used up by the melting 

 process, so that the air immediately above the ice becomes cooler ; this cooling 

 is occasionally so great that a thin layer of ice is formed on the lakes. It is 

 obvious that it cannot be any melting on a large scale which takes place during 

 July and the first half of August on the ocean-ice. In the latter half of 

 August the melting stops, the lakes are again covered with ice, and already 

 by the middle of September they are frozen to the bottom. 



Such is the summer on the ocean-ice and along the coast ; but if one goes 

 up into the mountains on land one soon discovers that the development is quite 

 different there. The first thing one observes is the drought which prevails ; 

 large stretches lie absolutely dried up, and one notices at once that nearly all 

 the snow has evaporated while the temperature was yet below zero. This will 

 be understood more easily if one takes into consideration that the downfall is 

 only one-sixth of the downfall in Denmark. Water running along the ground, 

 which is so common further towards the south, is almost absent here. It is 

 only under the glaciers and the snowdrifts that one finds water, and in these 

 places is vegetation. 



It is also quickly noticed that in July it becomes warmer as one ascends 

 from the coast. In order to examine this peculiar condition, it was decided 

 that Knud Rasmussen and Wulff should take the temperature on the coast 

 every hour for twenty-four consecutive hours, whilst I was to ascend a 

 thousand metres high mountain, examining the warm layer of air which must 

 evidently exist. We chose a steep coastal mountain by Dragon Point which 

 was 990 metres. I commenced the ascent on the 18th of July — that is, at the 

 height of summer — at six o'clock in the morning, reaching the top at 

 eight o'clock in the evening of the same day ; the descent was commenced an 

 hour later, and I was once more down by the tent at two o'clock in the morn- 

 ing of the 19th of July. The diagram will show the results of the readings. 



One notices at once that immediately above the ocean-ice there is a layer 

 of cold air which, in the course of the night, is further cooled down to below 

 zero, whilst by noon it is somewhat above plus 3° C. Above this layer of 

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