79 



In discussing these observations made at dif- 

 ferent seasons, we should compare the months, 

 which in both hemispheres are almost equally 

 distant from the solstices. It is necessary also 

 to pay attention to the slowness, with which, in 

 the temperate zone, the sea receives and loses 

 the heat communicated to it by the air. The 

 anomalies that take place proceed perhaps in 

 part from the variations, which the mean atmos- 

 pherical temperatures of the months undergo on 

 the same spot, but in different years. 



The preceding table shows, that the ideas 

 which are generally formed of the low temper- 

 ature of the southern hemisphere are not pre- 

 fectly accurate. Near the poles, and in very 

 high latitudes, the cold of the seas is undoubt- 

 edly less to the north than the south of the 

 equator ; but this difference is not sensible be- 

 tween the tropics ; it is even very little per- 

 ceptible as far as the 35th and 40th degrees of 

 latitude. 



Mr. Kirwan obtained an analogous result for 

 the air that rests on the ocean, by taking the 

 averages of a great number of observations made 

 during the winter and summer in each hemi- 

 sphere, and recorded in the journals of navi- 

 gators 1 *. From the equator to the thirty-fourth 



* See a very interesting paper by him in the Transactions 

 of the Irish Academy, vol. viii, p. 422. 



