8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. JO 



the second half of March and the first half of April, that is, for 

 the time interval from March i6 to April 15, which corresponds 

 closely with our second decade group, March 13 to April 13. We 

 computed also the general mean value of the mean temperatures 

 for each 2° field for February and for March- April for the years 

 1900 to 1910 in the same way as we used the observational material 

 of more southern regions, and we used the mean values so found as 

 the normals for each field. From this we obtained the anomaly 

 for each field for February and for the time interval from March 

 16 to April 15 for each year. 



The anomalies so found unfortunately could not be regarded as 

 very satisfactory, for even in the 2° fields they rested on too few 

 observations. By combining the mean of the anomalies for all 

 the 2° fields within each 10" longitude interval together, we may 

 suppose that values which will correspond better with the truth 

 would be obtained, since the accidental errors will thereby, at least 

 in a certain degree, be eliminated. 



In this way, the mean anomalies for 10° fields of longitude along 

 the route north of Scotland-New York were obtained lying within 

 the zones between 40° and 30° west longitude, 20° and 10° west 

 longitude and 10° and 0° west longitude. For these 10° longitude 

 fields, we have used only those 2° longitude fields in which the obser- 

 vations in the most years were most complete. The fields may on 

 this account be a little different for February and for the interval 

 March-April. They are, along with the corresponding tempera- 

 ture values given in table 4W and in plate 15 (21-24) where they 

 are indicated by cross-hatching. 



Along the route from the Faroe Islands to Iceland we have in 

 a similar way determined the temperature anomalies for large fields 

 for which sufficiently many observations were available. The fields 

 are shown on plate 15 (25-27) by cross-hatching, and in table 4W 

 indicated over the temperature values. Since the observational 

 material in March-April was considerably richer, more fields could 

 be employed in this interval than in the month of February. In 

 March-April also the voyages to Greenland were already begun, and 

 we could give the temperature. anomalies for some fields along this 

 route, also between 60° and 61° north latitude and westward from 

 20° to 28° west longitude (see tables 4W and pi. 15, 28). 



Finally, there were also in the fields between 0° and 3° west longi- 

 tude and between 56° and 57° north latitude, on the west coast of 

 Scotland so many observations that we also determined tempera- 



