420 



NATURE 



[March 3, 1898 



SCIENTIFIC ADVANTAGES OF AN 

 ANTARCTIC EXPEDITION} 



Dr. Murray's Address. 

 T7ROM a scientific point of view the advantages to be derived 

 ^ from a well-equipped and well-directed expedition to the 

 Antarctic would, at the present time, be manifold. Every 

 ■department of natural knowledge would be enriched by system- 

 atic observations as to the order in which phenomena coexist 

 and follow each other, in regions of the earth's surface about 

 which we know very little or are wholly ignorant. It is one of 

 the great objects of science to collect observations of the. kind 

 'here indicated, and it may be .safely said that without them we 

 •can never arrive at a right understanding of the phenomena by 

 which we are surrounded, even in the habitable parts of the 

 globe. 



Before considering the various orders of phenomena, concern- 

 •ing which fuller information is urgently desired, it may be well 

 to point out a fundamental topographical difference between the 

 Arctic and Antarctic. In the northern hemisphere there is a 

 polar sea almost completely surrounded by continental land, 

 and continental conditions for the most part prevail. In the 

 ■southern hemisphere, on the other hand, there is almost 

 ■certainly a continent at the South Pole, which is completely 

 surrounded by the ocean, and, in those latitudes, the most 

 ■simple and extended oceanic conditions on the surface of the 

 globe are encountered. 



The Atmosphere. 



One of the most remarkable features in the meteorology of 

 the globe is the low atmospheric pressure at all seasons in the 

 southern hemisphere south of latitude 45° S. , with the accom- 

 panying strong westerly and north-westerly winds, large rain 

 and snow fall, all round the South Polar regions. The mean 

 pressure seems to be less than 29 inches, which is much lower 

 than in similar latitudes in the northern hemisphere. Some 

 meteorologists hold that this vast cyclonic system and low- 

 pressure area continues south as far as the pole, the more 

 southerly parts being traversed by secondary cyclones. There 

 are, however, many indications that the extreme South Polar 

 area is occupied by a vast anticyclone, out of which winds blow 

 towards the girdle of low j^ressure outside the ice-bound region. 

 In support of this view it is pointed out that Ross's barometric 

 •observations indicate a gradual rise in the pressure south of the 

 latitude of 75° S. , and all Antarctic voyagers agree that when 

 near the ice the majority of the winds are from the south and 

 south-east, and bring clear weather with fall of temperature, 

 while northerly winds bring thick fogs with rise of temperature. 



All our knowledge of the meteorological conditions of the 

 Antarctic is limited to a few observations during the midsummer 

 months, and these indicate that the temperature of the snow- 

 covered Antarctic continent is even at that time much lower 

 than that of the surrounding sea. The anticyclonic area at the 

 South Pole appears therefore to be permanent, and when in 

 winter the sea-ice is for the most part continuous and extends 

 far to the north, the anticyclonic area has most probably a much 

 wider extension than in summer. This is indicated by the 

 south-easterly winds, which at times blow towards the southern 

 point of the American continent in June and July. 



All observations in high southern latitudes indicate an ex- 

 tremely low summer temperature. In winter we have no direct 

 observations. The mean of Ross's air temperatures south of 

 latitude 63° S. was 28*74° ^1 which is about the freezing-point 

 of sea-water, and his maximum temperature was 43*5° F. Both 

 Wilkes and D'Urville observed pools of fresh water on several 

 icebergs, and, when sailing along the ice barrier, Ross saw 

 "gigantic icicles depending from every projecting point of its 

 perpendicular cliffs" (Ross, "Antarctic Voyage," vol. i. p. 237), 

 so it is probable that extensive melting sometimes takes place. 



In the latitude of the Antarctic circle the air is frequently at 

 •or near the point of saturation, and precipitation takes place 

 in the form of rain, sleet, snow, or hail. Most of the observ- 

 ations near the ice-covered land show, however, a much drier 

 atmosphere, and in all probability precipitation oyer the Ant- 

 arctic continent takes place in the form of fine snow crystals, 

 such as is recorded in the interior of Greenland. 



There would appear, then, to be good reasons for believing 

 that the region of the South Pole is covered by what may be 

 regarded practically as a great permanent anticyclone, with a 



1 Address by Dr. John Murray, F.R.S., and subsequent speeches, 

 delivered at a special meeting of the Royal Society on February 24. 



much wider extension in winter than in summer. It is most 

 likely that the prevailing winds blow out from the pole all the 

 year round towards the surrounding sea, as in the case of Green- 

 land ; but, unlike Greenland, this area is probably seldom 

 traversed by cyclonic disturbances. 



But what has ibeen stated only shows how little real know- 

 ledge we possess concerning the atmospheric conditions of high 

 southern latitudes. It is certain, however, that even two years' 

 systematic observations within these regions would be of the 

 utmost value for the future of meteorological science. 



Antarctic Ice. 



From many points of view it would be important to learn 

 something about the condition and distribution of Antarctic sea- 

 ice during the winter months, and especially about the position 

 and movements of the huge table-shaped icebergs at this and 

 other seasons of the year. These flat-topped icebergs, with a 

 thickness of 1200 or 1500 feet, with their stratification and 

 their perpendicular cliffs, which rise 150 or 200 feet above and 

 sink 1 100 or 1400 feet below the level of the sea, form the most 

 striking peculiarity of the Antarctic Ocean. Their form and 

 structure seem clearly to indicate that they were formed on an 

 extended land surface, and have been pushed out over low-lying 

 coasts into the sea. 



Ross sailed for 300 miles along the face of a great ice-barrier 

 from 150 to 200 feet in height, off which he obtained depths of 

 1800 and 2400 feet. This was evidently the sea-front of a great 

 creeping glacier or ice-cap just then in the condition to give 

 birth to the table-shaped icebergs, miles in length, which have 

 been described by every Antarctic voyager. 



All Antarctic land is not, however, surrounded by such in- 

 accessible clilTs of ice. for along the seaward faces of the great 

 mountain ranges of Victoria Land the ice and snow which 

 descend to the sea apparently form cliffs not higher than 10 to 

 20 feet, and in 1895 Krisiensen and Borchgrevink landed on a 

 pebbly beach, occupied by a penguin rookery, at Cape Adare 

 without encountering any land-ice descending to the sea. Where 

 a penguin rookery is situated, we may be quite sure that there is 

 occasionally open water for a considerable portion of the year, and 

 that consequently landing might be effected without much diffi- 

 culty or delay, and further that a party, once landed, might with 

 safety winter at such a spot, where the penguins would furnish 

 an abundant supply of food and fuel. A properly equipped 

 party of observers situated at a point like this on the Antarctic 

 continent for one or two winters might carry out a most valuable 

 series of scientific observations, make sucessful excursions 

 towards the interior, and bring back valuable information as to 

 the probable thickness of the ice-cap, its temperature at 

 different levels, its rale of accumulation, and its motions, con- 

 cerning all which points there is much difference of opinion 

 among scientific men. 



Antarctic Land. 



Is there an Antarctic continent ? It has already been stated 

 that the form and structure of the Antarctic icebergs indicate 

 that they were built up on, and had flowed over, an extended 

 land surface. As these bergs are floated to the north and broken 

 up in warmer latitudes they distribute over the floor of the ocean 

 a large quantity of glaciated rock fragments and land detritus. 

 These materials were dredged up by the Challenger in consider- 

 able quantity, and they show that the rocks over which the Ant- 

 arctic land-ice moved were gneisses, granites, mica-schists, 

 quartziferous diorites, grained quartzites, sandstones, limestones, 

 and shales. These lithological types are distinctively indicative 

 of continental land, and there can be nodoubtabout their having 

 been transported from land situated towards the South Pole. 

 D'Urville describes rocky islets off Adelie Land composed of 

 granite and gneiss. Wilkes found on an iceberg, near the same 

 place, boulders of red sandstone and basalt. Borchgrevink and 

 Bull have brought back fragments of mica-schists and other con- 

 tinental rocks from Cape Adare. Dr. Donald brought back 

 from Joinville Island a piece of red jasper or chert containing 

 Radiolaria and Sponge spicules. Captain Larsen brought from 

 Seymour Island pieces of fossil coniferous wood, and also fossil 

 shells of Cttcnliaa, Cytherea, Cyprina, Teredo, and Natica, 

 having a close resemblance to species known to occur in lower 

 Tertiary beds in Britain and Patagonia. These fossil remains 

 indicate in these areas a much warmer climate in past times. 

 We are thus in possession of abundant indications that there is 

 a wide extent of continental land within the ice-bound regions 

 of the southern hemisphere. 



NO. 1479, VOL. 57] 



