ABSTRACT
And if thou wishest to know 'how long the moon will shine, and when it will set. Know thou that every day of the waxing moon addeth four minutes (or, measures (~ = KEVTflfJ<X) to its light until it is full, when it immediately beginneth to diminish, and each day its light diminisheth four minutes (or, measures). If it hath gone one day, or two, or Fol. 216a. however many days it be, double the number four times, and then see how many times four are contained in it, and the number of times will be the number of the minutes (or, measures) which the moon will shine. Every six minutes (or, measures) represent an hour. And if thou hast half a day, reckon to it two minutes (or, measures). And if the moon hath gone up more than fifteen days, then what remaineth to thee double in the same manner, and thus thou shalt find [the answer]. And · when thou hast counted fifteen minutes (or, measures), take away from them one minute (or, measure), because on the fifteenth day (the light of] the moon diminisheth one minute (or, measure). Now, an hour containeth thirty se'aryatha,t and the *a1l/l'ma 1 six. Each day the sun addeth one se'aretha, and when diminishing, he taketh away one se'aretlu'i [daily]; now, the poditlza ( = Gr. Tiou~) is one se'aretlza.
