The South Pole - Roald Amundsen (ebook reader for laptop TXT) 📗
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Wind.
For measuring the velocity of the wind the expedition had a cup and cross anemometer, which worked excellently the whole time. It consists of a horizontal cross with a hollow hemisphere on each of the four arms of the cross; the openings of the hemispheres are all turned towards the same side of the cross-arms, and the cross can revolve with a minimum of friction on a vertical axis at the point of junction. The axis is connected with a recording mechanism, which is set in motion at each observation and stopped after a lapse of half a minute, when the figure is read off. This figure denotes the velocity of the wind in metres per second, and is directly transferred to the tables (here converted into feet per second).
The monthly means vary between 1.9 metres (6.2 feet) in May, and 5.5
metres (18 feet) in October; the mean for the whole ten months is 3.4
metres (11.1 feet) per second. These velocities may be characterized as surprisingly small; and the number of stormy days agrees with this low velocity. Their number for the whole period is only 11, fairly evenly divided between the months; there are, however, five stormy days in succession in the spring months October and November.
The frequency of the various directions of the wind has been added up for each month, and gives the same characteristic distribution throughout the whole period. As a mean we have the following table, where the figures give the percentage of the total number of wind observations:
N.
N.E.
E.
S.E.
S.
S.W.
W.
N.W.
Calm.
1.9
7.8
31.9
6.9
12.3
14.3
2.6
1.1
21.3
Almost every third direction is E., next to which come S.W. and S. Real S.E., on the other hand, occurs comparatively rarely. Of N., N. W., and W. there is hardly anything. It may be interesting to see what the distribution is when only high winds are taken into account —
that is, winds with a velocity of 10 metres (32.8 feet) per second or more. We then have the following table of percentages: N.
N.E.
E.
S.E.
S.
S.W.
W.
N.W.
7
12
51
10
4
10
2
4
Here again, E. is predominant, as half the high winds come from this quarter. W. and N.W. together have only 6 per cent.
The total number of high winds is 51, or 5.6 per cent. of the total of wind observations.
The most frequent directions of storms are also E. and N.E.
The Aurora Australis.
During the winter months auroral displays were frequently seen —
altogether on sixty-five days in six months, or an average of every third day — but for want of apparatus no exhaustive observations could be attempted. The records are confined to brief notes of the position of the aurora at the times of the three daily observations.
The frequency of the different directions, reckoned in percentages of the total number of directions given, as for the wind, will be found in the following table:
N.
N.E.
E.
S.E.
S.
S.W.
W.
N.W.
Zenith.
18
17
16
9
8
3
8
13
8
N. and N.E. are the most frequent, and together make up one-third of all the directions recorded; but the nearest points on either side of this maximum — E. and N.W. — are also very frequent, so that these four points together — N.W., N., N.E., E. — have 64 per cent. of the whole. The rarest direction is S.W., with only 3 per cent. (From the position of the Magnetic Pole in relation to Framheim, one would rather have expected E. to be the most frequent, and W. the rarest, direction.) Probably the material before us is somewhat scanty for establishing these directions.
Meteorological Record from Framheim.
April, 1911 — January, 1912.
Height above sea-level, 36 feet. Gravity correction, .072 inch at 29.89 inches. Latitude, 78� 38’ S. Longitude, 163� 37’ W.
Explanation of Signs in the Tables.
SNOW signifies snow.
MIST ,, mist.
AURORA ,, aurora.
RINGSUN ,, large ring round the sun.
RINGMOON ,, ,, ,, moon.
STORM ,, storm
sq. ,, squalls
a. ,, a.m.
p. ,, p.m.
I., II, III., signify respectively 8 a.m., 2 p.m., and 8 p.m.
� (e.g., SNOW�) signifies slight.
2 (e.g., SNOW2) ,, heavy.
Times of day are always in local time.
The date was not changed on crossing the 180th meridian
Provisional Remarks on the Examination of the Geological Specimens Brought by Roald Amundsen’s South Polar Expedition from the Antarctic Continent (South Victoria Land and King Edward VII. Land). By J. Schetelig, Secretary of the Mineralogical Institute of Christiania University
The collection of specimens of rocks brought back by Mr. Roald Amundsen from his South Polar expedition has been sent by him to the Mineralogical Institute of the University, the Director of which, Professor W. C. Br�gger, has been good enough to entrust to me the work of examining this rare and valuable material, which gives us information of the structure of hitherto untrodden regions.
Roald Amundsen himself brought back altogether about twenty specimens of various kinds of rock from Mount Betty, which lies in lat. 85� 8’
S. Lieutenant Prestrud’s expedition to King Edward VII. Land collected in all about thirty specimens from Scott’s Nunatak, which was the only mountain bare of snow that this expedition met with on its route. A number of the stones from Scott’s Nunatak were brought away because they were thickly overgrown with lichens. These specimens of lichens have been sent to the Botanical Museum of the University.
A first cursory examination of the material was enough to show that the specimens from Mount Betty and Scott’s Nunatak consist exclusively of granitic rocks and crystalline schists. There were no specimens of sedimentary rocks which, by possibly containing fossils, might have contributed to the determination of the age of these mountains. Another thing that was immediately apparent was the striking agreement that exists between the rocks from these two places, lying so far apart. The distance from Mount Betty to Scott’s Nunatak is between seven and eight degrees of latitude.
I have examined the specimens microscopically.
From Mount Betty there are several specimens of white granite, with dark and light mica; it has a great resemblance to the white granites from Sogn, the Dovre district, and Nordland, in Norway. There is one very beautiful specimen of shining white, fine-grained granite aplite, with small, pale red garnets. These granites show in their exterior no sign of pressure structure. The remaining rocks from Mount Betty are gneissic granite, partly very rich in dark mica, and gneiss (granitic schist); besides mica schist, with veins of quartz.
From Scott’s Nunatak there are also several specimens of white granite, very like those from Mount Betty. The remaining rocks from here are richer in lime and iron, and show a series of gradual transitions from micacious granite, through grano-diorite to quartz diorite, with considerable quantities of dark mica, and green hornblende. In one of the specimens the quantity of free quartz is so small that the rock is almost a quartz-free diorite. The quartz diorites are: some medium-grained, some coarse-grained (quartz-diorite-pegmatite), with streaks of black mica. The schistose rocks from Scott’s Nunatak are streaked, and, in part, very fine-grained quartz diorite schists. Mica schists do not occur among the specimens from this mountain.
Our knowledge of the geology of South Victoria Land is mainly due to Scott’s expedition of 1901 — 1904, with H. T. Ferrar as geologist, and Shackleton’s expedition of 1907 — 08, with Professor David and R. Priestley as geologists. According to the investigations of these expeditions, South Victoria Land consists of a vast, ancient complex of crystalline schists and granitic rocks, large extents of which are covered by a sandstone formation (“Beacon Sandstone,”
Ferrar), on the whole horizontally bedded, which is at least 1,500 feet thick, and in which Shackleton found seams of coal and fossil wood (a coniferous tree). This, as it belongs to the Upper Devonian or Lower Carboniferous, determines a lower limit for the age of the sandstone formation. Shackleton also found in lat. 85� 15’ S. beds of limestone, which he regards as underlying and being older than the sandstone. In the limestone, which is also on the whole horizontally bedded, only radiolaria have been found. The limestone is probably of older Pal�ozoic age (? Silurian). It is, therefore, tolerably certain that the underlying older formation of gneisses, crystalline schists and granites, etc., is of Arch�an age, and belongs to the foundation rocks.
Volcanic rocks are only found along the coast of Ross Sea and on a range of islands parallel to the coast. Shackleton did not find volcanic rocks on his ascent from the Barrier on his route towards the South Pole.
G. T. Prior, who has described the rocks collected by Scott’s expedition, gives the following as belonging to the complex of foundation rocks: gneisses, granites, diorites, banatites, and other eruptive rocks, as well as crystalline limestone, with chondrodite. Professor David and R. Priestley, the geologists of Shackleton’s expedition, refer to Ferrar’s and Prior’s description of the foundation rocks, and state that according to their own investigations the foundation rocks consist of banded gneiss, gneissic granite, grano-diorite, and diorite rich in sphene, besides coarse crystalline limestone as enclosures in the gneiss.
This list of the most important rocks belonging to the foundation series of the parts of South Victoria Land already explored agrees so closely with the rocks from Mount Betty and Scott’s Nunatak, that there can be no doubt that the latter also belong to the foundation rocks.
From the exhaustive investigations carried out by Scott’s and Shackleton’s expeditions it appears that South Victoria Land is a plateau land, consisting of a foundation platform, of great thickness and prominence, above which lie remains, of greater or less extent, of Pal�ozoic formations, horizontally bedded. From the specimens of rock brought home by Roald Amundsen’s expedition it is established that the plateau of foundation rocks is continued eastward to Amundsen’s route to the South Pole, and that King Edward VII. Land is probably a northern continuation, on the eastern side of Ross Sea, of the foundation rock plateau of South Victoria Land.
Christiania,
September 26, 1912.
The Astronomical Observations at the Pole Note by Professor H. Geelmuyden
Christiania,
September 16, 1912.
When requested this summer to receive the astronomical observations from Roald Amundsen’s South Pole Expedition, for the purpose of working them out, I at once put myself in communication with Mr. A. Alexander (a mathematical master) to get him to undertake this work, while indicating the manner in which the materials could be best dealt with. As Mr. Alexander had in a very efficient manner participated in the working out of the observations from Nansen’s Fram Expedition, and since then had calculated the astronomical observations from Amundsen’s Gj�a Expedition, and from Captain Isachsen’s expeditions to Spitzbergen, I knew by experience that he was not only a reliable and painstaking calculator, but that he also has so full an insight into the theoretical basis, that he is capable of working without being bound down by instructions.
(Signed) H. Geelmuyden,
Professor of Astronomy,
The Observatory of the University,
Christiania.
Mr. Alexander’s Report.
Captain Roald Amundsen,
At your request I shall here give briefly the result of my examination of the observations from your South Pole Expedition. My calculations are based on the longitude for Framheim given to me by Lieutenant Prestrud, 163� 37’ W. of Greenwich. He describes this longitude as provisional, but only to such an extent that the final result cannot differ appreciably from it. My own results may also be somewhat modified on a final treatment of the material. But these modifications, again, will only be immaterial, and, in any case, will not affect the result
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