126 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 70 



tions of 2.2 meteorological principal stations. These values cover 

 several different months investigated. For the air temperature 

 curves there is a marked agreement with the curves of air pressure 

 gradients. The reader should take notice that the temperature scale 

 is twice as great for the water curves W, as for the air curves, L. 



For January, February, and March, the curve for Torungen, that 

 for all Norway, and in part that for Ona show greater agreement 

 with the corresponding air pressure curves for Torungen than with 

 the curves for Stad, but there is great similarity to those for both. 

 In January the curves of air temperature for Ona and for all Nor- 

 way show a great similarity (see pi. 47, fig. iL, Ona, and L, Nor- 

 way) . These two curves show certain agreement with the air pres- 

 sure gradient curves B for Stad and for Torungen. 



In February the curve for air temperature for Ona agrees better 

 with the curve for air pressure gradients for Torungen than for 

 Stad. This is particularly noticeable in the year 1901 and. also in 

 1910 when the curve for surface temperature for Ona has a quite 

 different run in comparison with the air pressure curve for Stad. 

 The air temperature curves for Torungen and for all Norway are 

 quite similar to the air temperature curve for Ona and agree very 

 well with the air pressure curves for Torungen. As an example 

 of a characteristic common to all three temperature curves, see for 

 instance the rise of the years 1900 to 1903. This rise we find also in 

 the curve of the air pressure gradients for Torungen, and not only 

 for February but also for the mean between January and February, 

 but not for the air pressure curve for Ona for the month of Febru- 

 ary, which gives a marked maximum in the year 1901, This shows 

 itself more strongly in the curve of surface temperatures for Ona 

 than in the curve of air temperature. The explanation is plainly 

 this : The winds as indicated by the isobars for February in this year 

 had a strong northerly direction at Stad and at Ona Lighthouse and 

 came from the ice ocean. It was a sea wind, which caused the rise 

 of the surface temperature at Ona, but at the same time cold winds 

 blew over Norway and the air temperature in February as well at 

 Ona and Torungen as also in all Norway was relatively lower. 

 These strong northerly winds appeared meanwhile not particularly 

 favorable for the rise of the surface temperature at Heliso or 

 Utsire, and least so at Torungen where the curves show no rise 

 corresponding to the maximum which we find at Ona. 



In March the curve of air temperature at Ona shows no very good 

 agreement with the curves of air pressure gradients either for Stad 



