182 Scientific Intelligence. — Meteorology. 



not, as is known, manifest themselves in the course of a single year, 

 to such a degree as very sensibly to affect the temperature as com- 

 pared with that of another year. The mean monthly variations of 

 a single year are infinitely more considerable. For tlie purpose of 

 estimating them with certainty, a series of annual observations is 

 required, such as is, as yet, collected for a, very small number of 

 places. There are, therefore, for the construction of lines of equal 

 monthly heat, out of the observations which we possess, three cor- 

 rections to be made; 1st, To free the observations which extend to 

 too short periods of the accidental deviations of the true means ; 

 2d, the elimination of the daily variations ; and 3d, The reducing 

 the observations to the sea-level. 



The researches which were submitted the preceding year to the 

 Academy, upon the extent which the same meteorological phe- 

 nomenon embraces, have demonstrated, that the wide differences 

 of different mean temperatures, are never a local phenomenon, 

 hut extend simultaneously over a large surface of the globe. We 

 may hence then conclude, that the deviations that are remarked 

 In a given place, will be observed also in another neighbouring 

 place. In the first of the tables formerly printed, there was cal- 

 culated the deviations of each month of the interval between the 

 year 1807 and 1824, upon the general means during that inter- 

 val for the following places, viz., Madras, Palermo, Nice, Mil.in, 

 Geneva, Carlsruhe, Stuttgard, Munich, Ratisbon, Paris, Placentia, 

 London, Carlisle, Dunfermline, Berlin, Dantzic, Stockholm, Tor- 

 neo and Salem. Let us suppose, for example, a spot placed in 

 the neighbourhood of Nice, and for which we are furnished with 

 observations from the year 1810 to 1815, it may be understood, 

 that the difference of the monthly mean of Nice in the same inter- 

 val of 1810-15 and that from 1807 to 1824, may he employed as 

 the element of correction for the observations made in this neigh- 

 bouring locality. By the combination of five different systems of 

 analogous observations, simultaneous in the interval of fifty years 

 in the district which embraces them all, it becomes possible to eli- 

 minate the non-periodic and purely fortuitous changes, whilst the 

 corrections dependent on the daily period, are calculated by parti- 

 cular tables prepared for this purpose for every month. The re- 

 duction, however, to the sea-level has presented the greatest diffi- 

 culties on account of its many varieties and its local circumstances. 



The final result of these researches may be expressed in the fol- 

 lowing terms : The cold poles of the earth, which, in the depth of 

 winter, are at their greatest mutual distance, and from the common 

 pole of rotation, in the summer approach nearer and nearer to each 



