Foreign Literature and Science. 



175 



It evidently appears from this table, 



1st. That in a synodical revolution of the moon, the ba- 

 rometer rises regularly from the second octant, when it is 

 the lowest, to the second quadrature, when it is the highest ; 

 and then descends to the second octant to commence again 

 its rise, &c. 



2d. The varying declination of the moon also modifies 

 her influence upon atmospheric pressure. It is greatest (at 

 least in the latitude of Viviers,) v/hen the moon's declina- 

 tion is south ; whence it evidently results that the barometer 

 is higher in the northern lunistice than in the southern. This 

 observation is contrary to v*^hat M. de Laplace had conclu- 

 ded from his theory, viz. " that the sign (signe) of the de- 

 clination of the two luminaries (sun and moon) has no sen- 

 sible influence on the modifications of the atmosphere."* 



3d. Lastly, the action of the moon, in diminishing the 

 pressure of the atmosphere, varies with its distance from the 

 earth. The mean height of the barometer is less when the 

 moon is in perigee than in apogee, whence we may infer 

 that her action in diminishing pressure, is greater in the for- 

 mer than in the latter situation. 



There exists between the phases of the moon and the 

 days of rain which coincide with these phases, a constant 

 relation which would appear very singular, if what we have 

 observed with respect to the barometer did not furnish an 

 immediate explanation. Agreeably to the extract which I 

 have made from my meteorological journal of the rainy days 

 which coincide with the days of the moon's phases and with 

 those of the perigee and apogee during the period of nine- 

 teen years, I have found the number of those days as follows. 



We perceive by this table that the number of rainy days 

 which coincide with the days of the phases, &c. follows the 

 same march with the mean heights of the barometer corres- 



* M6canique celeste, t. ii, p. 298, 



