^^ ■ p. A. ØYEN. 



overflow of the Upper Lake of Mjölkedal, mentioned above. When 

 entering upon my study of the glaciers of the Jotunheim in the 

 summer of 1891, I was informed by persons well acquainted with 

 the geographical conditions of the glaciers of that region, that a 

 continuous decrease of glacieis had been observed during the 

 thirty years preceding. 



Attention was, moreover, directed to the very interesting fact, 

 that the Tveraabræ and the Sveljenaasbræ, in the Government 

 Survey Map drawn in the years previous to the middle of the 

 century, are represented as joining into one common glacier, whose 

 previous existence is now indicated by a terminal moraine mar- 

 king a certain passage in the common history of the two gla- 

 ciers. In the new and completely revised edition of the Govern- 

 ment Survey Map made about 1870, the twin glaciers are, how- 

 ever, represented as altogether separate owing to their having 

 retired further; and this separation is now still wider on account 

 of the continued decrease of glaciers. 



About the same time we also meet with a few statements 

 of another kind with regard to oscillation of climate. In the years 

 1864 — 1868, a considerable change took place in the conditions 

 of perennial snow on the summit of the Galdhötind. In the first 

 of these years, the summit is stated to have been completely 

 covered with snow, but in the last, it was found to consist of 

 bare rock. During the period since elapsed, the summit of the 

 Galdhötind seems to have been always free from perennial snow. 

 Another phenomenon, also likely to attract attention, is the ice- 

 cover of the Lake of Juvvand. In the summer of 1864, this lake 

 was stated to be completely covered with a thick sheet of ice, 

 but in the summer of 1868, on one of the early days of August, 

 we find two enthusiastic tourists bathing in the open waters of 

 the lake. 



It is not only in the Jotunheim, however, that we may trace 

 the above-mentioned beginning of a decrease of glaciers. Blytt, 

 who, in the earlier years of the decade 1860 — 1870, made his 



