To knowe the quantite of houres in equales by day.
Understond wel that these houres inequales ben clepid houres
of planetes. And understond wel that som tyme ben thei lenger by
day than by night, and som tyme the contrarie. But understond wel
that evermo generaly the houre inequal of the day with the houre
inequal of the night contenen 30 degrees of the bordure, which
bordure is evermo answeryng to the degrees of the equinoxial.
Wherfore departe the arch of the day artificial in 12, and tak
there the quantite of the houre inequale by day. And if thou
abate the quantite of the houre inequale by day out of 30, than
shal the remenaunt that levith parforme the houre inequale by
night.