January 9, 19 13] 



NATURE 



515 



made. In a vessel of sea water was moored, at a 

 small distance from the surface, a piece of clear ice 

 (see Fig. ij. By means of a pipette the end of which 

 was drawn out into a long capillary tube, a line line 

 was drawn through the water in aniline blue dis- 

 solved in some of the sea water. The tube being very 

 fine, no disturbance was made by its passage through 

 the vi-ater, and the coloured line remained quite dis- 

 tinct. A straight line was drawn horizontally a little 

 above the top of the ice and its deformation by the 

 currents was watched, and the results are shown in the 

 figure. The end of the line over the ice quickly curved 

 upwards towards the surface. .A.t a short distance from 

 the ice it slowly bent downwards, and the successive 

 positions it assumed are shown in tlie figure. Next 



the ice the line 



'p^ kept only a small 



distance from it 

 all the way aown, 

 the upward cur- 

 rent flowing be- 

 tween it and the 

 ice, while the 

 downward current 

 carried the line 

 down to the 

 bottom of the ice, 

 where it curved 

 under the ice and 

 was carried to 

 the bottom of the 

 water. 



There is still 

 another question 

 to which an 

 answer is re- 

 quired. In these 

 experiments a 1 1 

 the water is at the 

 same temperature, 

 while in the sea 

 this is not the 

 case; the temperature there falls with the depth. 

 .\nd the question now is : How will this affect the 

 circulation ? Will the cold melted ice and sea water 

 rise up through the warmer water ? To get an answer , 

 to this question a tall jar about one foot deep was 

 filled with sea water and surrounded for fully half 

 its depth with ice and water. No salt was put in 

 the cooling mixture lust the low temperature so pro- 

 duced should cause some of the sea water to freeze 

 and so increase the density of the bottom water and 

 interfere with the circulation. The water in the jar 

 was cooled until the bottom temperature was 34° F., 

 the surface temperature 41°, and the temperature at 

 mid-depth 37'5°. A long rod of blue ice was now placed 

 in the water. The rod extended from the bottom to the 

 surface. The result was that all the blue as before came 

 to the surface, showing that even the fall of tempera- 

 ture with depth in the sea does not seem likely to 

 interfere with the rise of the ice-cooled water. This 

 result might have been anticipated, because the ice- 

 cooled water tends to rise at whatever temperature the 

 melting takes places, and, having started to rise, it 

 gradually acquires the temperature of the warmer 

 water through which it rises. 



All these tests tend to prove that the ice-cooled sea 

 water will come to the surface, while Prof. Barnes's 

 latest investigations on icebergs show that in certain 

 cases it does not. I am sure the readers of Nature will 

 look forward with interest to anv further observations 

 Prof. Barnes may make with his verv ingenious and 

 delicate microthermograph, which may help to clear 

 up the difference he has observed in the surface water 

 surrounding different icebergs, and also the difference 



NO. 2254, VOL. 90] 



. I. — r, the coloured line drawn through 

 llie water ; 2, 3, 4 and 5, position of the 

 !ine at successive intervals of time pro- 

 duced by the currents. 



he has found in actual icebergs compared with labora- 

 tory experiments. Prof. Barnes, in your issue of 

 December 12, gives a sketch to show- the way in 

 which he thinks an iceberg is eaten away by the sea 

 water. The current is shown flowing on the surface 

 towards the iceberg and eating it away quickest at the 

 line of flotation. On looking at the sketch one cannot 

 help asking, What has become of the light ice-cooled 

 water? Should anyone be fortunate enough to see an 

 iceberg tumble over on its side he may gain some 

 information from an examination of its shape and 

 from noting where the greatest amount of eating 

 away had been done. But for his observations to be 

 of value he would require to know something about 

 the temperature of the sea at the bottom of the iceberg 

 as well as at the surface ; because, while ice melts 

 quickest at the bottom, where the rising current first 

 comes in contact with the ice, if the temperature is 

 the same all the way down, yet we cannot expect this 

 to happen if the temperature at the bottom of the 

 berg is much lower than at the surface. 



John Aitken. 

 .^rdenlea, Falkirk, December 27, 1912. 



AMVNDSEti'S ANTARCTIC EXPEDITION.^- 



MR. MURRAY has produced in a singularly 

 attractive form a remarkably clear and 

 readaDle translation by Mr. Chater of Captain 

 Roald Amundsen's account of his expedition to 

 the Antarctic regions in the Fram, which culmin- 

 ated in the attainment of the south pole, and 

 settled the last of the old romantic problems of 

 exploration. The main and avowed object of 

 Amundsen's expedition was to reach the pole; 

 everything else, including scientific observations, 

 was merely incidental, so that at first sight it 

 might appear that little notice need be taken in 

 a scientific' journal of the story of a big piece of 

 record-breaking. In other places the ethics of 

 record-breaking have been freely discussed in 

 connection with this expedition, and the question 

 has been raised w-hether it is decent and permis- 

 sible for two explorers to try to reach the same 

 point at the same time from different bases and 

 by different means. The controversial aspects of 

 Captain .Amundsen's book do not concern us here, 

 nor need we allow our national feelings to affect 

 our opinion as to the manner in which the 

 Norwegian expedition was designed, executed, 

 and described. 



The pursuance of the main aim of the expedition 

 was a splendid example of efficiency in plan, 

 equipment, transport, phj'sical strength and 

 skilled leadership. The plan was simplicity itself. 

 It was to land and set up winter quarters on the 

 Great Ice Barrier at 163° 30' W. and 78° -30' S., 

 to form depots at intervals as far south as 82° 

 before winter set in, and to store the farthest depot 

 with sufficient food to carrv a sledge-party from 

 there to the pole and back and leave enough in re- 

 serve to secure their return to the base ; then in the 

 Antarctic spring to travel with light sledges and 

 many dogs to the farthest depot, tliere to complete 

 supplies and proceed due south to the pole, trust- 



' " The South Pole." An Account of the Norwegian Antarctic Expedi- 

 tion in the J^rnm, 1910-1912. By Roald Amundsen. Translated from the 

 Norwegian by A. G. Chater. Vol. i., pp. xxxv f 392-{-plates-f-map. 

 Vol. li., pp. x-f- 449 -t-plates-t- maps. (London; John Murray, 1912.) Price, 

 2 vols. 2/ 2S. net. 



