Jökull - 01.11.1998, Blaðsíða 35

Sveinn Pálsson's time, Mýrdalsjökull and Eyjafjalla-
jökull were connected by a perennial snowfield, not
solid glacier ice. Eyjafjallajökull was the name applied
to the entire ice cap. Nowadays, the two ice caps are
separate because of thinning of the once contiguous ice-
and-snow mass and separation at the saddle [“Lág-
jökull” on Sveinn Pálsson's 1795 map] between them.
12. Hrútárjökull is the next outlet glacier to the east of Kví-
sker. In Pálsson's time Fjallsjökull, still farther to the
east, was solidly connected at its terminus to Hrútár-
jökull. Both of those are clearly visible from Sveinn
Pálsson's viewpoint. Nowadays, the ogives on Fjalls-
jökull, the more prominent of the two outlet glaciers,
are much more conspicuous.
13. Sveinn Pálsson is describing here the concept of plastic
flow or deformation of glacier ice.
14. Sveinn Pálsson apparently observed large ice crystals in
the lower parts oí the glacier.
15. Jón Eyþórsson (1945, p. 765) shows 6,000 feet for the
height of Öræfajökull. The original manuscript indi-
cates 6,060 Danish feet. The Danish foot, at the time,
equaled 314 mm. He also thought that Sveinn Pálsson's
elevations were too high. The difference between
Sveinn Pálsson's results (1,903 m.a.s.l.) and the current-
ly accepted elevation (1,927 m.a.s.l. on the peak that
Sveinn supposedly visited) is as close as can be expect-
ed (-1%) by a measurement using an uncalibrated
barometer, without reference to a base-station barome-
ter. His other measurements of the heights of mountains
(Eyjafjallajökull: 1,610 m.a.s.l. vs. 1,666 m.a.s.L; and
Hekla: 1,581 m.a.s.l. vs. 1,447 m.a.s.l., errors of -3 per-
cent and 8 percent, respectively) indicate that his mea-
surements of elevations of mountain summits by
barometer were sometimes not so reliable. The over es-
timated elevation of Snæfell is based on the estimate
that he was 1/3 up the mountain when he was forced
back by foul weather.
REFERENCES
Björnsson, F. 1957. Gengið á Öræfajökul í slóð Sveins
Pálssonar. Jökull, 7, 37-39.
Björnsson, F. 1965. Varða Sveins Pálssonar. Jökull, 15,121.
Bordier, A. C. 1775. Voyage Pittoresque aux Glacier de
Savoye fait en 1772. Geneve, Caille L. A., 303 pp [cited
by Tyndall, J. 1874. Theforms ofwater. London, Henry
S. King and Co. ]
Pálsson, S. 1945. Jöklaritið. Ferðabók Sveins Pálssonar.
Dagbœkur og ritgerðir 1791-1797. Reykjavík, Snæ-
landsútgáfan, 423-552.
Thorarinsson, S. 1960. Glaciological knowledge in Iceland
before 1800. A historical outline. Jökull, 10,1-18.
Ágrip
Ur Jöklaritinu
I greininni er birt ensk þýðing á þeim hluta Jökla-
rits Sveins Pálssonar þar sem lýst er göngu hans á
Öræfajökul 1794. Þar kemur fram að Sveinn taldi
svigður á Hrútárjökli eða Fjallsjökli, sem bar fyrir
augu hans í ferðinni, staðfesta þá kenningu hans að
jökulís væri seigfljótandi og hnigi undan halla líkt og
viðarkvoða. Þar var Sveinn langt á undan sinni samtíð í
skilningi á eðli jökla.
JÖKULL, No. 46, 1998
33