VI. The moon's orbit around the earth is inclined at an angle of about 5° to the earth's orbit around the sun. The moon, therefore, appears to an observer on the earth as if traversing a great circle of the celestial sphere just as the sun appears to do; and the moon's real orbit projected against the celestial sphere appears as a great circle similar to the ecliptic. This great circle in which the moon appears to travel will, therefore, be inclined to the ecliptic at an angle of 5° and the moon will appear in its motion never far from the ecliptic; it will always be within the zodiac which extends eight or nine degrees on either side of the ecliptic. The angular velocity of the moon's motion in its projected great circle is much greater than that of the sun in the ecliptic. Both bodies appear to move in the same direction, from west to east; but the solar apparent revolution takes about a year averaging 1° daily, while the moon completes a revolution from any fixed star back to the same star in about 27-1/4 days, making an average daily angular motion of about 13°. The actual daily angular motion of the moon varies considerably; hence in trying to test out Chaucer's references to lunar angular velocity it would not be correct to make use only of the average angular velocity since his references apply to specific times and therefore the variation in the moon's angular velocity must be taken into account. VII. On the line "In two of Taur," etc., Skeat has the following note: "Tyrwhitt unluckily altered _two_ to _ten_, on the plea that 'the time (_four days complete_, l. 1893) is not sufficient for the moon to pass from the second degree of Taurus into Cancer? And he then proceeds to shew this, taking the _mean_ daily motion of the moon as being 13 degrees, 10 minutes, and 35 seconds. But, as Mr. Brae has shewn, in his edition of Chaucer's Astrolabe, p. 93, footnote, it is a mistake to reckon here the moon's _mean_ motion; we must rather consider her _actual_ motion. The question is simply, can the moon move from the 2nd degree of Taurus to the 1st of Cancer (through 59 degrees) in four days? Mr. Brae says decidedly, that examples of such motion are to be seen 'in every almanac.' For example, in the Nautical Almanac, in June, 1886, the moon's longitude at noon was 30° 22' on the 9th, and 90° 17' on the 13th; i. e., the moon was in the _first_ of Taurus on the former day, and in the _first_ of Cancer on the latter day, at the same hour; which gives (very nearly) a degree more of change of longitude than we here require. The MSS all have _two_ or _tuo_, and they are quite right. The motion of the moon is so variable that the mean motion affords no safe guide." [Skeat, _Notes to the Canterbury Tales_, p. 363.]