Meteorological I tiflnence of the Moon. 69 



variations exist, one dependent upon the sun''s diurnal move- 

 ment, and another upon his annual : the hottest period of the 

 day and year corresponds to the mmimum of the height of the 

 barometer, and the extreme period during the diurnal period 

 reaches 1,1 lines, from 9 h. to 4, He then examines the in- 

 fluence of the phases, and the variations from the declination 

 and the distance of the moon. The smallest barometrical 

 height corresponds to the second day after the full moon, 

 and the greatest to the new moon, as at Berlin ; the difference 

 is only 0',194, and the uncertainty only 0^06. Although the 

 effect of the change of the moon in declination should not be 

 very sensible in latitude 5°, it nevertheless reaches 0*,289 ; 

 and the regularity of the progress of these results appears to 

 leave no doubt as to the existence of this variation. The 

 minimum height corresponds to the greatest northern declina- 

 tion, and the maximum occurs two or three days after the 

 descending node. Regarding the differences arising from those 

 of the distance of the moon and earth, they are in the same 

 directions as those found in higher latitudes, but they are too 

 small to be susceptible of a precise valuation from so small a 

 number of observations. M. Madler concludes from these re- 

 searches, that we cannot refuse to the moon some influence 

 upon the earth as it regards its climate, although this influence 

 is very small, and subordinate to that of the sun, and to other 

 causes of variation which are still unknown. He admits, 

 among others, that those years in which the moon attains its 

 greatest northern and southern declinations, ought to be com- 

 paratively more favourable as to weather, and particularly for 

 the cultivation of the vine, than those in which it is less re- 

 moved from the equator. Finally, he thinks that the general 

 laws of gravity are insufficient to explain these effects, as much 

 in regard to quality as quantity, and that the properties of 

 the moon''s light, which we know theoretically, are still more 

 so. 



