The Roman history of Ammianus Marcellinus, during the reigns of the emperors Constantius, Julian, Jovianus, Valentinian, and Valens.

Book XX.11
Its appearance, as far as mortal sight can discern, is, in the first line yellow, in the second tawny, in the third scarlet, in the fourth purple, and in the last a mixture of blue and green.
And it is so tempered with this mixed beauty, as mankind believe, because its first portion is discerned in a thin diluted state, of the same colour as the air which surrounds it; the next line is tawny, that is a somewhat richer colour than yellow ; the third is scarlet, because it is opposite to the bright rays of the sun, and so pumps up and appropriates, if one may so say, the most subtle portion of its beams ; the fourth is purple, because the density of the spray by which the splendour of the sun's rays is quenched shines between, and so it assumes a colour near that of flame ; and as that colour is the more diffused, it shades off into blue and green.

α           ©