74 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DeC. 1 7j 



On examining this table, we remark that in latitude 20° N. or 

 20° S., the mean of the temperatures of the land stations exceeds the 

 mean of the sea stations ; and in latitude 30° N. there is a similar 

 small excess. In latitude 40° N. there is no sensible excess, and in 

 latitude 50° N. the mean of the two land stations is about 10° less 

 than that of the sea stations. It would thus appear that the effect 

 of continents within the first 40° of latitude has the effect of increasing 

 slightly the mean annual temperature of the most central parts of 

 such continents, although it would appear from the previous table 

 (art. 1 7, p. 72) that the existence of such continents within the above 

 latitude has no appreciable effect in elevating the mean annual tem- 

 perature of the whole parallel. The depression of the mean annual 

 temperature at the land stations, compared with that of the sea sta- 

 tions, in latitude 50°, is large. We might hence be led to conclude 

 that a diminution of land and increase of sea along that parallel, such 

 as would result from the depression of Europe beneath the ocean, 

 would be attended with a considerable increase in mean annual tem- 

 perature in the region thus become sea. This effect, however, would 

 be very different in different continental regions along the same par- 

 allel. The effect would be greatest in the most central parts of the 

 continent, and least in the vicinity of its bounding shores. To find 

 the effect of the submersion of Europe, we may compare the mean 

 annual temperatures at the two sea stations already given on the 

 parallel of 50° with two other land stations on that parallel, one in 

 western Europe (long. 10° E,), and another in eastern Europe (long. 

 30° E.). The temperatures of these stations (assuming always the 

 absence of the Gulf-stream) will be — 





Long. 

 10° E. 



Diff. 



Long. 

 30° E. 



Difif. 



January temperature. . . 

 July temperature 



251 

 65 1 



40 



ill 

 68/ 



54 





45 





41 







The mean of 45° and 41° is 43°, which is not 1° less than the mean 

 of the two sea stations of the same latitude. This tends to prove 

 that the conversion of Europe into sea would have little effect on the 

 mean annual temperature of those portions of it which lie contiguous 

 to the parallel of 50° latitude, and especially in western Europe, the 

 region, for instance, lying between the parallels of the Alps and the 

 southern shores of the Baltic. At the same time the winter tempe- 

 rature would be increased and that of summer diminished to an equal 

 amount, since their mean remains the same. If we suppose the 

 change in each of these temperatures to be 4° for the station above- 

 mentioned (long. 10° E.), we shall have for that station, — 



DifF. 



January temperature 29° 1 oqo 



July „ 6 1 J 



Mean 45 



