34 plikt's nattteal history. [Book n. 



CHAP. 7. — OF THE ECLIPSES OE THE MOOTT AND THE SUIT. 



For it is evident that tlie sun is hid by the intervention^ 

 of the moon, and the moon by the opposition^ of the earth, 

 and that these changes are mutual, the moon, by her inter- 

 position\ taking the rays of the sun from the earth, and the 

 earth from the moon. As she advances darkness is suddenly 

 produced, and again the sun is obscured by her shade ; for 

 night is nothing more than the shade of the earth. The 

 figure of this shade is like that of a pyramid or an inverted 

 top^ ; and the moon enters it only near its point, and it does 

 not exceed the height of the moon, for there is no other star 

 which is obscured in the same manner, while a figure of this 

 kind always terminates in a point. The flight of birds, when 

 very lofby, shows that shadows do not extend beyond a certain 

 distance ; their limit appears to be the termination of the 

 air and the commencement of the aether. Above the moon 

 everything is pure and full of an eternal light. The stars 

 are visible to us in the night, in the same way that other 

 luminous bodies are seen in the dark. It is from these causes 

 that the moon is eclipsed during the night^. The two kinds 

 of eclipses are not, however, at the stated monthly periods, 

 on account of the obliquity of the zodiac, and the irregularly 

 wandering course of the moon, as stated above ; besides that 

 the motions of these stars do not always occur exactly at the 

 same points'*. 



I have seldom if ever perused a translation of any classical author, where, 

 on scientific topics, the translator has not endeavoured, more or less, to 

 correct the mistakes of the original, and to adapt his translation to the 

 state of modem science. 



^ The terms here employed are respectively interventus, objectio, and 

 interpositus ; it may be doubted whether the author intended to employ 

 them in the precise sense which is indicated by their etymology. 



2 " metsB et turbini inverso." The metcB were small pyramids placed 

 at the two extremities of the spina, or central division of the circus : see 

 Montfaucon, v. iii. p. 176 ; Adam, p. 341. 



3 The echpses of the moon are only visible when the spectator is so 

 situated as to be able to observe the shadow of the earth, or is on that 

 side of the earth which is turned from the sun. 



^ " non semper in scrupuHs partimn congruente siderum motu." On. 

 the term scrupulus Hardouin remarks, " Scrupuh, nodi sunt, in quibus 

 circuU, quos in suo cursu Sol et Luna efficiunt, se mutuo secant." 

 Lemaire, ii. 251. Ptolemy, Magn. Const, vi. 6-11, gives a full and ge- 

 nerally correct account of the principal phaenomena of echpses. 



