0)1 the Surface Temperature of Xorfh Sea anel North Atlantic. 27 



Maximum is less than half a degree higlier than at 15° W. In the 

 North Sea, the anomaly varies from less than 1° C. in the western 

 half of the sea to over 2° C. along its eastern shores, and is above 3° 

 in tlie German Hight and in the eastern part of the Skagerrack. Off 

 the west of Scotland and west of Ireland, there is an area in which 

 the anomaly is considerably higher than at the stations around ; but 

 the area so atiected can only be roughly and approximately indicated 

 on our chart. 



As regards the mean Minimum Temperatures, our chart (Fig. 11), 

 showing the anomalies from 15° W., has a different appearance from 

 the corresponding chart of mean maxima. But it will bo fo\nul that 

 the difference is mainly one of degree, the proximity of land having 

 a greater influence in lowering the winter temperatures than in 

 raising the summer temperatures of the sea. While our maximal 

 i.sanomalies never exceeded 3° C, our chart of minimal isanomalies 

 shows a range of -from 0° to 7° C. The general arrangement of the 

 lines, however, is very much the same as before, and the largest 

 anomalies are again found in the German Bight and as we pass 

 through the Skagerrack towards the Baltic Sea. 



When we come to examine our twelve monthly charts (Figs. 13- 

 24) of Mean Sea Temperature we are struck by the very great 

 differences which exist from one month to another in regard to the 

 distribution and direction of the isotherms. These differences can all 

 be understood, after due consideration, in the light of the general 

 phenomena which we have now explained ; and the chief cause of 

 the altered direction of the isotherms, from season to season, evidently 

 lies in the great variation of amjditude from one part of our area to 

 auother. About the month of June and again about the month of 

 October the isotherms run approximately east and west across our 

 area, subject of course to the various bendings or infoldings which are 

 caused by currents and other secondary factors. But, on the other 

 hand, from about February to April the isotherms around our coasts 

 and especially in the eastern parts of the North Sea, run almost due 

 north and south, while again from July to Septemljer they are 

 steeply inclined in an opposite direction. This is all simply due to 

 the fact that, at the season of minimum in early spring the waters in 

 the south-eastern part of the North Sea are unduly cool, and the 

 isotherms passing through this area are accordingly linked up with 

 those far to the northward thereof. While, on the other hand, in 

 summer and early autumn, about the season of the maximal sea 

 temperature, the exceptionally heated waters of the eastern and 

 south-eastern North Sea have a temperature similar to that of the 

 ocean considerably to the southward. 



It seems worth while, in order to get a general view of this 

 phenomenon, to construct a series of schematic diagrams, such as 

 those shown in Fig. 12. The construction of these diagrams is as 

 follows : We begin by making a quadrilateral upon the chart, 

 bounded on the east and west by the meridians of 5° E. and 15° W., 

 and northward by the parallel of 60° N. ; the south-western corner 

 of our quadrilateral is in 50° N, and the south-eastern corner is in 

 53° N., that is to say in the southern North Sea, off the Frisian 

 coast. Now suppose that we take, from month to month, the 



