318 Cofiiieanon qfilie Moan with Rain, 



19th October 1808 to the 18th October 1827), I have found the 

 following numbers of days. 



It is seen by this table, that the numbers of rainy days which 

 coincide with the days of the moon's phases, and of the perigee 

 and apogee, follow the same progress as the mean heights of the 

 barometer corresponding to these phases, but in the inverse ra- 

 tio. Thus the number of days of new moon on which it rained 

 is less than the number of days of full moon on which it rained ; 

 and the mean height of the barometer, the day of the moon's 

 conjunction, is, on the contrary, greater than on the day of her 

 opposition. In like manner, the number of rainy days that agreed 

 with the first quarter, much exceeds the number of rainy days that 

 coincided with the last quarter, and the mean height of the ba- 

 rometer is much less in the first quarter than in the last quar- 

 ter. Lastly, the number of rainy days that have coincided with 

 the days on which the moon was perigee, is much greater than 

 the number of rainy days that corresponded with the days on 

 which she was apogee ; and, on the contrary, the mean height 

 of the barometer when the moon is perigee, is much less than 

 the mean height of that instrument when the moon is apogee. 



All this is perfectly explained, by the constant observation, 

 which has long been made, that it rains more frequently when 

 it is high. Thus, the superiority of the number of rainy days 

 corresponding to the full moon, in the first quarter and perigee, 

 over the number of rainy days that coincide with the new moon, 

 the last quarter and the apogee, arises from the circumstance 

 that the barometer is lower and the pressure of the atmosphere 

 less in these three first lunar periods, than in the three last. 

 Thus, all that can be concluded from our remark is, that the 

 diminution of the atmospheric pressure, caused by the moon's 

 attraction, must be reckoned among the causes that determine 

 the fall of rain. * 



