483 



summer solstice, and the one law passes into the other at the epochs 

 of the equinoxes, exactly as for the solar diurnal variation. 

 6th. For the moon on the equator going south. 



a. About perihelion. The lunar diurnal law consists of two 

 nearly equal maxima near the superior and inferior transits : of the 

 two intermediate minima, the moonset minimum is by far the most 

 marked. 



b. AJbout aphelion. The law consists of two nearly equal minima 

 near the superior and inferior transits : of the two intermediate 

 maxima, that near moonrise is by far the most marked. 



c. In this case also the laws for the solstices are the opposite of 

 each other, and the one law passes into the other near the epochs of 

 the equinoxes. 



7th. For the moon furthest south. 



a. About perihelion. The lunar diurnal law consists of maxima 

 near the upper and lower transits, that at the upper transit being by 

 far the most marked : of the intermediate minima, that near moon- 

 set is the greater. 



b. About aphelion. The law consists of two minima, the most 

 marked at the inferior transit, the other about three hours before the 

 superior transit ; and of two equal maxima, one near moonrise, the 

 other near the superior transit, but varying little till 3 hours before 

 the inferior passage. 



c. In this instance the inversion is not so complete as in the other 

 cases ; this, it is believed, will be found to be due to the fact that the 

 change from one law to the other takes place after the vernal and 

 before the autumnal equinox ; so that in the means for six months, 

 from which the above conclusions are drawn, the lunations following 

 the law a are combined with those belonging to b. 



8th. The moon on the equator going north. 



a. About perihelion. The lunar diurnal law consists of two nearly 

 equal maxima when the moon is near the superior and inferior meri- 

 dians ; of the two intermediate minima, that near moonrise is by far 

 the most marked. 



b. About aphelion. The law consists of two minima at the infe- 

 rior and superior transits ; and of two maxima, the greatest at moon- 

 set, the other between the meridians of 16 h and 21 h ; between these 

 points there is an inflexion constituting a slight minimum. 



