( 16 ) 



The differences between the calculated and observed baro- 

 metric pressures are contained in the 3 d and 5 tü columns of 

 Table IY. These differences are small and do not show a 

 distinct periodicity; those contained in the 3 d column are not 

 much less than those contained in the 5 th column. Therefore 

 I think it sufficiënt to take only three terms into account, and 

 think it very probable that the mean barometric pressures at 

 different times of the lunar day at Batavia are represented by 

 the formula: 



J B==:758.9839 + O.O184^(0+39o31 / ) + O.O5535m(2e + 64o2O') 

 The mean barometric pressure of the lunar day is represented 

 by the first term ; the variation of the barometric pressure du- 

 ring the lunar day is represented by the two last terms; the 

 3 d term represents a line with two maxima and two minima, 

 the 2 d term a line with one maximum and one minimum. By 

 the 3 d term a regular tide is represented; by the 2 d term is 

 represented that the tidal movement in the atmosphere is larger 

 when the moon is above, than when it is under the horizon. 



In how far the Lunar Atmospheric Tide at Batavia is really 

 represented by this formula, must be decided by the discussion 

 of a longer series of observations ; it is likely that the coëffi- 

 ciënt of the 2 d term will be found to have too great a value, 

 because the difference between the two maxima is greater than 

 could be expected by the range of the variation of the distance 

 of the moon to the place of observation during a lunar day. 



The maxima and minima of the mean barometric pressures 

 during the lunar day, and the times when they occur, accor- 

 ding to this formula, are contained in Table V. 





TABLE Y. 







Lunar time. 



Barometric pressures. 



l st Maximum 

 1 st Minimum 

 2 d Maximum 

 2 d Minimum 



Batavia, March 7 th , 



1870 



h 



1.04 



7.12 



12.65 



18.62 



mm 



759.054 

 75S.939 

 759.025 

 758.917 



