176 . 



as well as in the reflected light of the planets, was recognized 

 at a very early period; but o : ir knowledge of this remarkable 

 phenomenon has been greatly extended by the aid of telescopic 

 vision, more especially since attention has been so especially 

 directed to the double stars. We do not here allude to the 

 change of colour which, as already observed, accompanies 

 scintillation even in the whitest stars, and still less to the 

 transient and generally red colour exhibited by stellar light 

 near the horizon, (a phenomenon owing to the character of 

 the atmospheric medium through which we see it,) but to the 

 white or coloured stellar light radiated from each cosmical 

 body, in consequence of its peculiar luminous process, and the 

 different constitution of its surface. The Greek astronomers 

 were acquainted with red stars only, while modern science has 

 discovered, by the aid of the telescope, in the radiant fields of 

 the starry heaven, as in the blossoms of the phanero- 

 gamia, and in the metallic oxides, almost all the gradations of 

 the prismatic spectrum between the extremes of refrangibility of 

 the red and the violet ray. Ptolemy enumerates in his catalogue 

 of the fixed stars six (vnoKippoi) fiery red stars, viz i 46 Arcturus 

 Aldebaran. Pollux, An tares, a Orionis (in the right shoulder), 



The expression vrroKippos, which Ptolemy employs indis- 

 criminately to designate the six stars named in his catalogue, 

 implies a slightly marked transition from fiery -yellow to fiery - 

 red; it therefore refers, strictly speaking, to a fiery -reddish 

 colour. He seems to attach the general predicate avQ6s, 

 fiery-yellow, to all the other fixed stars. (Almag., viii. 3 ed. 

 Halma, torn. ii. p. 94.) Kippos is, according to Galen, (Meth. 

 med. 12,) a pale fiery-red inclining to yellow. Gellius com- 

 pares the word with melinus. which, according to Servius, has 

 the same meaning as " giivus' 1 and " fulvus." As Sirius 

 is said by Seneca (Nat. Qucest., i. 1) to be redder than Mars, 

 and belongs to the stars called in the Almagest inroKippo^ 

 there can be no doubt that the word implies the predominance, 

 or, at all events, a certain proportion of red rays. The asser- 

 tion that the affix iroMnAof, which Aratus, v. 327, attaches to 



