440 



noticeable wherever land meets sea and may probably be attributed to the temperature gradient between 

 the land and the water. 



On the coastlines of the great continents the phenomenon is for the most part marked by the tendency 

 of the average wind to follow the direction of the littoral. This is well shown in the ' Wind Charts of the 

 Coastal Regions of South America,' prepared in the Meteorological Office and published by the Admiralty. 

 There is also evidence in favour of the existence of a similar state of things in high latitudes. 



The point is strikingly illustrated in the pressure and temperature maps given in the 'Atlas Climato- 

 logique de PEmpire de Russie,' published in St. Petersburg, in 1900, by the Observatoire Physique 

 Central Nicolas. 



In this atlas the maps devoted to mean monthly temperature of the air show that during the four 

 months December to March the isotherms along the eastern seaboard of Siberia and, to some extent, along 

 the northern seaboard also, run almost parallel to the coast, and that the temperature gradient is inland 

 towards a minimum situated on about the 135th meridian of east longitude, in the neighbourhood of the 

 Arctic Circle. 



The maps dealing with atmospheric pressure and wind resultants for the same months exhibit isobars 

 which also run almost parallel to the northern and eastern seaboards, and the pressure gradient is seaward 

 from a maximum situated over some locality in about the centre of Asia. 



In the maps relating to the three months April to June, the temperature gradient is shown to be from 

 the south towards a minimum over the Arctic Ocean ; but in May and June a gradient is indicated towards 

 the eastern seaboard as well. 



In the maps for pressure for the three months the isobars display, by their tendency to turn northwards 

 as they approach the Arctic Ocean, the transitional condition of the atmosphere characteristic of the 

 season. 



In July and August the conditions which obtained during the four months December to March are more 

 or less completely inverted. Isotherms affect the contour of the northern seaboard, and incline coastwise 

 on the eastern coast also, but the temperature gradient is from inland towards the sea. The isobars for 

 these months outline roughly the trend of the littoral, but the pressure gradient is inland from the sea. 



For the months of September to November, inclusive, the general distribution of temperature and 

 pressure indicated differ but little from those which characterise December to March, but, while the 

 relation between temperature and pressure is almost as clearly defined in the former period as it is in 

 the latter, the September to November period is, in addition, marked by some features which appertain to 

 the three transitional months April to June. Thus we should not be surprised to find some correspondence 

 between the general run of the isobars and the coastline of the Antarctic Continent. The variation from 

 Winter to Summer is less marked, possibly because the cold centre remains in approximately the same 

 position in both seasons and the arrangement is subject only to variation of a local character. 



From the 6th to the 9th November, between latitude 78 15' S., longitude 168 10' E., and latitude 

 78 40' S., longitude 167 53' E., there occurred a period of unsettled weather which may be touched on in 

 order to illustrate conditions occasionally experienced by Captain SCOTT and his party during their 

 southern journey. 



At 2 p.m. on 6th November the barometer, corrected for an altitude of 150 feet to sea-level, stood at 

 29 30 inches, and the thermometer at 1 5 F. There was a light air from north-west, and the " weather 

 throughout the day beautifully fine." At 9 p.m. pressure and temperature had not changed, but the light 

 air had died away. At 10 p.m. on the 6th to 4 p.m. on the 7th a hard blizzard was blowing from south- 

 west, with exception of a lull at 2.30 a.m. The smoke from Mount Erebus was observed to be moving 

 from south-west. The wind moderated and the weather improved at 5 p.m., and an hour after there 

 was only a light air from north-west. The mercury had dropped very little, and at 9 p.m. stood at 

 29 27 inches, but the temperature had fallen to - 4 F. The weather was noted as " b." 



A light air continued to come from north-west until after 4 a.m. on the 8th, and at 6 a.m. a blizzard was 

 again experienced which lasted throughout the day, with the wind from south-south-west, force 2-5. The 

 barometer was rising ; temperature fluctuating, but higher. The snow drift is described as heavy all day. 

 The wind dropped towards 6 p.m., but freshened at 10 p.m. 



