290 THORODDSEN 



inhabited districts, because there alone permanent meteorological 

 stations are found. The climate of the uninhabited plateau is far 

 less known. Although it is possible, from the climate at the coast, 

 to draw fairly definite conclusions as regards the climate of the 

 interior, derived from the height above sea-level and the distance 

 from the coast, yet almost all accurate investigations and observa- 

 tions from the plateau are wanting. The only climatological station 

 on the plateau is MoSrudalur (469 metres above sea-level), and it 

 will be seen that the climate there is far more severe than at the 

 coast (see Table IV), from which again may be concluded how very 

 severe must be the winter up at the Jokulls in the centre of the 

 island, at a height of 1000 1400 metres; the climate in the interior 

 is certainly far more continental than at the coast. The winter in 

 \165rudalur (mean temperature - 7.2 C.) is almost twice as severe 

 as in the inhabited districts of North Iceland at any height up to 

 100 metres above sea-level, with a mean temperature of 3.5 C. 

 The spring of M65rudalur is very cold with a mean temperature 

 of 2.1C., and the mean autumn temperature is also below 

 zero (-- 0.7 C.), but the summer is as warm as at the coast. On 

 Odadahraun and north of Arnarfellsjokull the winter is beyond 

 doubt very severe, with perhaps a mean temperature of 10 

 or less. That the frost persists for a long time is seen by a tew 

 small oases, where the snow does not thaw until during July and 

 where a miserable vegetation appears only for a period of two 

 months. On the plateau the storms blow with great force, driving 

 sand , gravel and small rock-fragments across the desolate plains 

 and ridges of rock, thereby striating and polishing them ; as men- 

 tioned above, the wind also carries great quantities of tufT-dust and 

 blown sand from the plateau down to the valleys and lowlands. 

 During summer it may sometimes become fairly warm in the middle 

 of the day, but, in the interior of the plateau, it usually freezes 

 during the night, so that small water-courses and pools of water 

 are ice-covered early in the morning. Snow-storms occur now and 

 then, and sand- and rain-storms and fogs are very common. The 

 large Jokull -domes in the centre of the plateau often appear to 

 form a climatic boundary, the weather frequently being opposite 

 in character to the north and south of them. Thus, there is often 

 bright sunshine on ArnarvatnsheiSi, north of Langjokull, while south- 

 easterly storms of rain are raging over the plateau south of the 

 same Jokull; conversely it may be warm sunshiny weather on the 



