164 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 70 



tions in the earth's atmosphere. We shall later return to Koppen's 

 paper. 



As we were on the point of finishing this work, Krogness published 

 (1917) in the Journal " Naturen " March, 1917, an interesting article 

 on the dependence between magnetic storms and meteorological 

 variations. The article is in part the result of highly valuable ob- 

 servations which Krogness made at the Haldde Observatory in Fin- 

 mark. He urges that the variations in the earth's magnetism are at 

 least as good a measure of the variations of the solar activity as the 

 relative sun spot numbers which have been used principally hitherto. 

 By employing the observations of the Christiania Observatory on 

 the daily variations of the magnetic declination as a measure of the 

 magnetic storminess, he finds that the eleven-year variations in this 

 correspond directly to an eleven-year variation in the surface tem- 

 perature at Ona Lighthouse on the Norwegian west coast. The cor- 

 relation occurs in this way : that a maximum of temperature occurs 

 at the time of maximum magnetic storminess and therefore at the 

 time of sun spot maximum (compare Helland-Hansen and Nansen, 

 1909, fig. 73). He has investigated the relation between the varia- 

 tions in the magnetic storminess and the air temperature at different 

 stations in Norway at different seasons of the year, both in the north 

 (Alten and Andenes) and further south (Christiansund and Do- 

 maas). He finds that in March- April there is a good agreement in 

 the variations of the magnetic storminess and the temperature varia- 

 tions not only in the stations which he investigated but also on the 

 whole in all Norway (22 meteorological stations), so that the maxi- 

 mum magnetic storminess occurs a little before the maximum of air 

 temperature. But different relations hold for other seasons of the 

 year. In January, for example, the temperature variations at the 

 stations he employed as well as in all Norway go in opposite direction 

 to the variations of the magnetic storminess. Indications of the same 

 kind are found in the autumn in the months September and October 

 particularly in northern Norway. Considering the whole year as a 

 unit, there appears to be a certain indication of agreement between 

 temperature variations and variations in the magnetic storminess, 

 but such that the maximum of temperature falls on the average a 

 couple of years after the maximum of magnetic storminess. Krog- 

 ness appears to think that the variations in the solar radiation which 

 reaches the earth has a direct influence on the air temperature of the 

 earth's surface at the different stations, and that this in combination 

 with variations in the air circulation and outgoing radiation is the 

 cause of the observed agreement which he finds between temperature 



