2 5 2 THE POPULAR SCIENCE MONTHLY 



low temperatures of the south polar summer, which are probably due 

 to the great continental mass of ice around the south pole, are respon- 

 sible for much of the difficulty of Antarctic exploration. The average 

 annual temperatures have been in the vicinity of 10°-15° ; and the 

 minima of an ordinary Antarctic winter go down to — 40°, and below, 

 but so far no minima of the severest Siberian intensity have been noted. 

 The British expedition on the Discovery recorded a minimum tem- 

 perature of — 67.7°, and also noted — 40° in midsummer. The 

 highest temperatures have varied between about 35° and 50°. It is likely 

 that near the south pole will prove to be the coldest point on the earth's 

 surface in the average for the year, and also that the lowest winter and 

 summer temperatures in the southern hemisphere will be found in the 

 immediate vicinity of the pole. 



The polar zones have a permanent deficiency of precipitation (15- 

 10 inches, or less). The polar deserts of snow and ice are therefore 

 deserts in more senses than one, although it is natural that these ex- 

 tended snow and ice fields should tend to give an exaggerated idea of 

 the actual amount of snowfall. So far as exploration has yet gone into 

 the highest northern latitudes, rain has been found to fall in summer, 

 and it is doubtful whether there are any places in the world, near sea- 

 level where all the precipitation comes in the form of snow. Perhaps 

 the interior of the south polar continent may never have rain. The 

 snow of the polar regions is characteristically fine and dry, and it has 

 been pointed out that the snow huts of the Eskimos could not be built 

 with our kind of snow. At low polar temperatures flakes of snow are 

 not found, but precipitation is in the form of ice spicules. 



The inner polar areas seem to be beyond the reach of the most fre- 

 quent and most violent storms, and as most of the observations thus far 

 obtained from the Antarctic come from the marginal zone of great storm 

 activity, violent winds and wet, disagreeable weather, they do not show 

 us the features of the actual south polar climate. Extraordinary rec- 

 ords of storm and gale have been brought back from the far south and 

 the far north. During the long, dreary winter night the temperature 

 falls to very low readings. Snowstorms and gales alternate at irregular 

 intervals with calmer spells of more extreme cold and clear skies. 

 There is no really warm season. The summer is essentially only a 

 modified winter, especially in the Antarctic. Yet the Arctic summer, 

 with its long days, crisp, clean air and sunshine, has many attractive 

 qualities, and we may fairly safely predict a considerable development 

 of summer resorts within the Arctic circle for the pleasure-loving, 

 wealthy and unoccupied persons of the north temperate zone. 



Climate and Health. — We have now seen something of the climatic 

 zones and of their characteristics. Let us turn for a few minutes to the 

 question of climate and health — a subject which is surely of the great- 

 est concern to man. From the earliest times people have sought in 



