VOL. LXV.] PHILOSOPHICAL TRANGACTIONS. 623 



formed in any state of the air, if the moon was not actually hidden by a cloud, 

 or obscured by sensible mists. The prognostics furnished by the new moon 

 ser\'ed only till the dichotomy, and those of the dichotomy till the full moon, 

 and so on ; not because a new and distinct influence was exerted in each new 

 aspect, but because each new aspect furnished a new set of signs, of a different 

 kind. That this is a true representation of the most ancient lunar prognostics, 

 appears from hence ; that others of a similar kind were derived from the sun and 

 the fixed stars, particularly the Prsesepe and Aselli in Cancer, and the bright 

 star in the Altar ; and it is remarkable, that Aratus says, the prognostics taken 

 from the sun are the most certain of all. * The vulgar soon began to consider 

 those things as causes, which had been proposed to them only as signs. The 

 manifest effect of the moon on the ocean, while the mechanical cause of it was 

 totally unknown, was interpreted as an argument of her influence over all ter- 

 restrial things ; and these notions were so consistent with that visionary philoso- 

 phy, which assigned distinct places to corruption, change, and passivity, on the 

 one side, and the active governing powers of nature on the other, and made the 

 orb of the moon the boundary between the two, that they who should have 

 been its opponents, ranged themselves on the side of popular prejudice. And 

 the uncertain conclusions of an ill-conducted analogy, and a false metaphysic, 

 were mixed with the few simple precepts derived from observation, which pro- 

 bably made the whole of the science of prognostication in its earliest and purest 

 state. Hence both Theophrastus and Aratus teach us to remark the position of 

 the moon's horns, and take conjectures of approaching fair weather or tempest, 

 according as they appear, at different times of the moon's age, erect, reclined, 

 or prone : not knowing that the position of the line joining the moon's cusps, 

 with respect to the horizon, depends merely on the mutual approach, or recess, 

 of the pole of a great circle drawn through the centres of the sun and moon, 

 and the pole of the horizon, in the course of the diurnal revolution. And so 

 great a man as Varro, as he is quoted by Pliny, was not ashamed to give this 

 childish rule, for predicting the weather, for a whole month to come, from ap- 

 pearances at the new moon. " If the upper horn be obscure, the decline of the 

 moon will bring rain. If the lower horn, the rain will happen before the full. 

 At the time of the full moon, if the blackness be in the middle."-|- After this 

 one cannot be surprized, that the poet Virgil should make the prognostics of the 

 4th day decisive for the whole lunation : 



* HfAiM K«i /UiSaAii' UiMTet trii/iXTU xUTcii. Ai6irii(«>«i«.— Orig, 



+ Apud Varronem ita est. Nascens Luna si cornu superiore obatro surget, pluvias decres- 



cens dabit : si inferiorCj ante plenilunium : si in media nigritia ilia fuerit, imbrem in plenilunio. 

 Plin. Nat. Hist. lib. xviii. cap. 35. — Orig. 



