440 



It will be seen from this Table that the calculated range 

 has two maxima and two minima in the month, the maxima 

 occurring one or two days after syzigies, and the minima one 

 or two days after quadratures. This result agrees very closely 

 with that deduced from a direct examination of the mean 

 ranges, as given in the former communication. 



The morning range varies within wider limits than the 

 evening one, the extreme variation of the former being l'*85, 

 and that of the latter l'-60 ; their mean variations are l'*60 

 and l'-20 respectively. This difference is due to the circum- 

 stance that the interval between the epochs of greatest and 

 least declination in the former case is six hours, which is also 

 the interval between the maxima and minima of the lunar 

 change ; and consequently the lunar variation is doubled in 

 its effect upon the range. In the case of the evening range, 

 on the other hand, the interval of greatest and least declina- 

 tion is nine hours, and they cannot, therefore, both coincide 

 with the extremes of the lunar variation. 



