la SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 'JO 



chart for the time interval 1900-1910. Here, however, we have 

 not employed the mean temperatures for the single fields but have 

 endeavored to determine an average form of the isotherms for each 

 full degree for each year. In this we have taken account of the 

 fact that these isotherms always show tongue-like forms, and that 

 these alter somewhat from year to year. If one should compute 

 isotherms from the mean temperatures fo'r the whole time interval, 



Figure 8. The wind conditions in tlie North Atlantic Ocean in January 

 and February according to Angot's Meteorologie and Hahn's Lehrbuch der 

 Meteorologie. We have also drawn the isobars for February in the North 

 Atlantic. 



these tongues would more or less disappear. We have endeavored 

 to determine the average position of each of these tongues, and 

 although our result cannot claim great accuracy, yet we hope it 

 may give a better general impression of the nature of the tempera- 

 ture distribution. 



In plate 8 there is given a chart of the average temperatures and 

 isotherms for the three decades, March 15 to April 13, for the time 

 interval from 1900 to 1910, in accordance with our investigations. 



