BY CAPTAIN F. W. HUTTON. 435 



the ice is protected fi'om the direct rays of the sun by this thick 

 surface moraine the ablation of the glacier is caused chiefly by 

 rain. During my visit heavy rain, with a north-west wind, fell 

 continuously for two days. This rain had, during the second day, 

 a temperature of 50° F., while that of the air at 9 a.m. was 56° F. 

 As soon as the rain was over I visited the outlet of the glacier and 

 found that the water, which was rushing out with great force, had 

 a temperature of 32^° F. It follows there foi-e that the rain had 

 lost 14|^° F. of temperature, which must have been mainly 

 expended in melting ice. Rain from the south-east varied in 

 temperature from 45° F. to 48° F. 



One of the most remarkable features of the Mueller Glacier is 

 the two large lateral moraines which cross transversely the Hooker 

 Valley, and between which the glacier flows far out from the 

 mountain valley without any increase in breadth. In this respect 

 it resembles the glacier of La Brenva^ south of Mont Blanc, 

 which crosses the AUee Blanche, and the glacier of AUalein, which 

 crosses, in the same way, the valley of the Saas, north of Monte 

 Rosa. Of these lateral moraines the northern one is comparatively 

 simple, being composed only of two moraines, a smaller one inside a 

 larger; but the southern lateral moraine is much more compli- 

 cated. These lateral moraines are due to the immense quantity 

 of debris on the lower part of the glacier, which is constantly 

 being shed off at the sides. In this way the glacier, when it 

 emerges from the mountain valley, builds up a wall on each side, 

 and between these walls the glacier advances over the plain, 

 instead of spreading out in a fan, as it must have done if the 

 surface of the ice had been clean. 



The northern lateral moraine starts from a small unnamed 

 tributary glacier a little to the west of Nicolo Point, and continues 

 for about a mile and a half, gradually curving down the valley 

 from E.S.E. to S.E. It is, as I have said, double. The outer 

 portion is, where highest, about 400 feet above the upper Hooker 

 Valley, and is covered with alpine vegetation. Inside this and a 

 hundred feet lowei', is another moraine, more recent and destitute 

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