From those references to the moon that occur in Chaucer's poetry alone, it would be impossible to determine just how much he knew of the peculiarities of her apparent movements; for he alludes to the moon's motion and positions much less frequently and with much less detail than to those of the sun. But a passage in the prologue to the _Astrolabe_ leaves it without doubt that Chaucer was quite familiar with lunar phenomena. In stating what the treatise is to contain, he says of the fourth part: "The whiche ferthe partie in special shal shewen a table of the verray moeving of the mone from houre to houre, every day and in every signe, after thyn almenak; upon which table ther folwith a canon, suffisant to teche as wel the maner of the wyrking of that same conclusioun, as to knowe in oure orizonte with which degree of the zodiac that the mone ariseth in any latitude;"[84] As a matter of fact the treatise as first contemplated by Chaucer was never finished; only the first two parts were written. But Chaucer would scarcely have written thus definitely of his plan for the fourth part of the work unless he had had fairly complete knowledge of the phenomena connected with the moon's movements. The moon, in Chaucer's imagination, must have occupied rather an insignificant position among the heavenly bodies as far as appealing to his sense of beauty was concerned, for we find in his poetry no descriptions of her appearance that can compare with his descriptions of the sun or even of the stars. He speaks of moonrise in the most general way: "hit fil, upon a night, When that the mone up-reysed had her light, This noble quene un-to her reste wente;"[85] He applies to her only a few epithets, the most eulogistic of which is "Lucina the shene."[86] In comparing the sun with the other heavenly bodies the poet mentions the moon among the rest without distinction, as inferior to the sun: "For I dar swere, withoute doute, That as the someres sonne bright Is fairer, clerer, and hath more light Than any planete, (is) in heven, The mone, or the sterres seven, For al the worlde, so had she Surmounted hem alle of beaute," etc.[87] On the other hand, the stars are elsewhere said to be like small candles in comparison with the moon: "And cleer as (is) the mone-light, Ageyn whom alle the sterres semen But smale candels, as we demen."[88] Whenever Chaucer mentions the moon's position in the heavens he does so by reference to the signs of the zodiac[89] and, as in the case of the sun, usually with the purpose of showing time. In the _Marchantes Tale_ he expresses the passage of four days thus: "The mone that, at noon, was, thilke day That Ianuarie hath wedded fresshe May, In two of Taur, was in-to Cancre gliden; So long hath Maius in hir chambre biden,"[90] and a few lines further on he states the fact explicitly: