His allusions to the motions of the moon, both diurnal and monthly, show plainly that he understood them well. His new moon appears in the evening, his waning moon rises late at night and sets in morning sunshine,[171] and his full moon comes on the meridian at midnight, for when he wishes to describe her at her brightest, as a comparison with a very brilliant light, he places her in a clear sky at midnight in her mid-month.[172] In the middle of a lunar month the moon is full, and being exactly opposite the sun will reach the meridian at midnight: this therefore is the time when she gives all the light she possibly can. In the Quæstio[173] Dante mentions that the moon does not move in the celestial equator, but sometimes north of it, and sometimes an equal amount south; in the Convivio he indicates the length of her period, and briefly describes her phases and their cause—“Ora luce da un lato, e ora luce dall’ altro, secondo che ’l sole la vede.”[174]
Her position in the zodiac is mentioned several times. In one passage he indicates a very brief space of time in the following curious way:—
“Quando ambo e due i figli di Latona, Coperti del Montone e della Libra, Fanno dell’ orizzonte insieme zona, Quant’ è dal punto che il zenit inlibra. Infin che l’uno e l’altro da quel cinto, Cambiando l’emisperio, si dilibra, Tanto, col volto di riso dipinto, Si tacque Beatrice.”[175]
That is to say, when Sun and Moon (the children of Latona) are both on the horizon, but one being in Aries and the other in Libra they are opposite one another, the zenith for a moment holds them, as it were, in balance; but the next moment one will drop below the horizon while the other rises above it, thus changing from the visible to the invisible hemisphere and vice versa, as each frees itself (“si dilibra”) of the common horizon that girdled them. The pause of Beatrice was as brief as the time during which sun and moon would thus hang in the balance.
Yet, though Dante shows that he was familiar with the movements and appearances of the moon, his allusions to her are cold and comparatively rare. Unlike modern poets, moonlight does not seem to have had any great fascination for him. In all his works there are only fifty-one references to the moon, and far the greater number of these are remarks about the measurement of time, or else her phases, her markings, her share in causing eclipses etc. In all his short poems (including those of the Vita Nuova and Convivio) there are but two references, and those as dry as possible. “Più lune”[176] is once used, meaning several months, and in a sonnet which describes the influences of each heaven on his lady, all he can find to say of the moon’s is “E ’l primo ciel di sè già non l’è duro.”[177]
The chill of moonlight is spoken of as with a shudder on the hill of Purgatory;[178] and its usefulness is recognized rather grudgingly when Virgil remarks that yesternight the moon was full, and adds that Dante must remember it, since it did him no harm in the depths of the Forest.[179] It is true there is some beauty in the description of the aurora which preceded moonrise[180] on the first night in Purgatory, but Dante gives it an ugly name, and the waning moon when seen on the following night, four days after full, is oddly compared to a bucket in shape. Dante did not admire this gibbous form, for he instances the outline of the moon when not quite full as an ignoble curve, contrasting it with the beauty of a perfect circle.[181]
Fig. 39. Sun, moon, and zenith.