Jökull - 01.12.1960, Blaðsíða 11

is crushed. Thus arise the “jökúlhlaups” in
Jökulsá. These jökulhlaups usually occur once
a year, and the shorter the intervals are be-
tween tliem the smaller they are” (op. cit.).
Neither the sketch map nor the descrip-
tion are in Arni’s handwriting (the description
probably in the handwriting of his secretary,
M. Einarsson) but both were certainly made
during Arni’s tours of inspections in Vestur-
Skaftafellssýsíá in 1704 and 1705. The descrip-
tion is in all probability derived from a local
farmer and is still another proof of the keen-
ness with the farmers observed nature.
A description of Austur-Skaftafellssýsla, writ-
ten by the district sheriff, SigUrdur Stefánsson,
and dated July 21st, 1746, contains a fairly
thorough description of all glacier rivers in
that district and some important information
on the position of the glaciers at that time
(Sýslulýsingar 1744-1749; Sögurit XXVIII, pp.
1-23).
The poet and naturalist Eggert Ólafsson
(1726—1768) studied natural history in Copen-
hagen. Together with the physicist Bjarni Páls-
son he travelled through Iceland every sunnner
frorn 1750 to 1757 studying every aspect of the
natural liistory and geography o£ the country,
and wrote a very comprehensive account of
these travels (Vice-Lavmand Eggert Olafssens og
Landphysici Bjarne Povelsens Reise igiennem
Island. Soröe 1772). In this work Olafsson re-
peatedly discusses glacial phenomena, without
however adding much new knowledge.
Ólafsson was more affected by academic theo-
ries than Vídalín and had still less respect for
the opinion of common people. Most note-
worthy is probably what he has to say of a
small cirque glacier on the northern side of
Skardslieidi: “when we passed here on August
6th [1752, auth. rem.j, we noticed high up on
the mountain a fairly large patch, which looked
like glacier ice. The owner of the nearest farm,
Mófellsstadir, in reply to our question whether
the ice on Mófell did not melt in summer,
not only answered no, but added that when
lie was a boy he never saw any ice at all
there; but that wen he after many years ab-
sence returned some years ago lie had noticed
a beginning accumulation of snow, and that
gradually less of it melted away in the summer.
The place is facing NW, and the ice already
shows cracks of a green colour due to the re-
fraction usual on thick glaciers. Tliis indicates
that the ice may increase and new glaciers
form even on moderately high mountains in
tliis neighbourhood, provided the periodical
cold winds persist year after year” (op. cit. p. 83).
Besides a remarkable description of the origin
of a cirque glacier, we have here an attempt
at a climatological explanation of that pheno-
menon.
Ólafsson makes an attempt at a morpho-
logical classification of the glaciers in Iceland.
He distinguishes between “Haa-Jöklar” or high
ice mountains .... “Skrid-Jöklar” or low gla-
ciers resulting from ice slips and ice falls and
“Grunn-Jöklar” where the ground freezes to
ice on flat, low-lying land. “Breidamerkurjökull
is the only one we know of this kind” (op. cit.
p. 788). This is the first mention in literature
of the Icelandic term skri.ðjökull (from the Ice-
landic skríða — creep, glide), which literally
means glacier that glides. In all probability
this term is much older, however. Ólafsson
writes rightly about the high glaciers: “The ice
mountains or liigh glaciers reach, as mentioned
above, high up in the air where it is much
colder than on flat, low-lying land. On them
rain will change into snow and ice and as they
always attract rain, clouds, and fog, they will
maintain their size and grow unless the sun
can every year melt as much as is added to
them”, but after this correct conclusion he
rambles off into fantasy, saying that a better
explanation of how a glacier ice is maintained
is that the glaciers have free communication
with the sea by hidden channels and increase
frorn below (p. 788). Academic theories conflict
here again with common sense and with facts
that seemed obvious to the local farmers. The
same applies to an older paper of liis, Enarra-
tiones historicœ de natura et constitutione Is-
landiœ (Hafniae 1749), where he disputes the
opinion of his countrymen on what causes the
colour of the glacier rivers. They maintain that
the rivers get their light colour from the glaciers.
Olafsson contends that they get it from lime
(pp. 132—173). In Iceland there is hardly any
lime.
Ólafsson is the first man in Iceland and prob-
ably in the world to discuss the formation of
dirt cones on glaciers. In the Alps dirt cones
are for the first time mentioned by Gruner in
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