( 14 ) 



5 th and 7 th columns is ram .1165; the difference between tbese 

 two means is mm 005. 



I think it necessary to add that not much value should be 

 attached to the results contained in the Tables II and III; to 

 deeide these questions a much longer series of observations than 

 one of three years must be discus sed, 



From the numbers contained in the 5 th column of Table I 

 I have deduced a periodic formula representing the variation 

 of the mean barometric pressure during the lunar day. This 

 formula is : 



mm mm mm 



fi--=758 9839+0 0184m' v e+39 ftl') + 0.0553«w(2o+64°20') 

 mm 



-f- Q.OOWsin (3 + 326° 1') -f etc. 



In this formula B is the mean barometric pressure at that 

 time of the lunar day, at whicli the hour angle of the moon 

 is 0. 



The mean barometric pressures at the several lunar hours 

 have been calculated by means of this formula, firstly, taking 

 into account only three terms, secondly, taking into account 

 four terms. The calculated barometric pressures are given in 

 the 2 d and 4 th columns of Table IV. 



