The Barddas of Iolo Morganwg, Vol. I., ed. by J. Williams Ab Ithel, , at sacred-texts.com
The four parts of the day: morning, that is, the first six hours; vapourlessness, the second six hours; noon, the third six hours; and the fourth, evanescence, 1 reaching till the morning.
423:1 p. 422 Al, "rest."