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THORODDSEN 



of Berufjord) there are 143 foggy days. In other places fogs are 

 much rarer; for instance on Grimsey there are on an average 46 

 foggy days, the majority of which occur during summer, while at 

 Stykkisholm there are only nine. Along Hornstrandir fogs are very 

 common especially during ice-years, but from this locality no ob- 

 servations are to hand. 



The amount of snow varies greatly according to situation and 

 height above sea-level, and from year to year. In North Iceland 

 snow often persists for a long time during winter, but in south- 

 west Iceland the weather is always stormy and unsettled; conse- 

 quently, in the lowlands the winter-snow r rarely persists for a long 

 time. Frost and thaw often alternate daily. In South Iceland it 

 often happens during winter that no snow is to be seen for months 

 in the lowlands. On the other hand, it rains very often, and the 

 precipitation which falls here as rain, produces on the plateau con- 

 siderable masses of snow. By way of exemplifying the durability 

 of the snow-covering, I give the results of my observations the 

 number of days with snow-covering in Reykjavik during the 

 winters of 1889-1892 and 18931895 in the following table: 



In these five winters it snowed for the first time on Oct. 28, 

 Sept. 28, Oct. 24, Sept. 19 and Oct. 31 respectively; for the last time 

 on March 20, April 18, April 26, March 30 and April 18. Very often 

 the snow persisted for a day or two only. The longest period during 

 which the ground was covered continually with snow, was in the 

 winter of 189192, viz. 63 days, from Jan. 19 to March 21. In all 

 these winters the neighbouring Akrafjall, which has an altitude of 

 364 metres was often entirely snowless. In several places in North 



