197 the longitudes of the visible Moon and the Sun computed for sunrise); and on them apply the method of successive approxi- mations (to obtain the nearest approximation to the time between the visible Moon and the Sun computed for moonrise, i.e., between the risings of the Moon and the Sun). The Moon, who is like a looking glass for the face of the directions, rises as many asus before sunrise as correspond to the nādis obtained by the method of successive approximations. MERIDIAN PASSAGE OF THE MOON A rule for the determination of the time of the meridian passage of the Moon, and the longitudes of the Moon and the meridian- ecliptic point at that time : 39. Infer by your intellect the time when the meridian- ecliptic point and the Moon are together. Then, by the method of successive approximations, find out the nearest approxi- mations for that time, the longitude of the Moon, and the longitude of the meridian-ecliptic point (for that time). Assuming that the rising point of the ecliptic is three signs in advance of the meridian-ecliptic point, the time to elapse before or elapsed since the Moon is on the meridian is the same as the time to elapse before or elapsed since the point of the ecliptic three signs in advance of the Moon is on the horizon. Therefore in order to get an approxi- mate time when the Moon occupies the meridian-ecliptic point one may proceed as follows: First calculate the longitudes of the Sun, the Moon, and the rising point of the ecliptic with the help of the given time. Then increase the longitude of the Moon by three signs and find the time due to the oblique ascension of the part of the ecliptic lying between the rising point and the Moon as increased by three signs. The time thus obtained is the approximate time to elapse before or elapsed since the meridian passage of the Moon. From this calculate the time of the meridian passage of the Moon. Details of the method of successive approximations contemplat- ed in the above rule: 40. Determine the nadis intervening between the Moon and the meridian-ecliptic point (for the time determined by inference) with the help of the times of rising of the signs at Lanka. When (the longitude of the Moon is) less (than the
