48 COSMOS. 



tc capacity, which was the same among former generations, 

 as, for instance, the Greeks and Romans, as at the present 

 day. The Pleiades prove that several thousand years ago, 

 even as now, stars which astronomers regard as of the sev- 

 enth magnitude, wer^ invisible to the naked eye of average 

 visual power. The group of the Pleiades consists of one 

 star of the third magnitude, Alcyone ; of two of the fourth, 

 Electra and Atlas ; of three of the fifth, Merope, Ma'ia, and 

 Taygeta ; of two between the sixth and the seventh magni- 

 tudes, Pleione and Celaeno ; of one between the seventh and 

 the eighth, Asterope ; and of many very minute telescopic 

 stars. I make use of the nomenclature and order of succes 

 sion at present adopted, as the same names were among the 

 ancients in part applied to other stars. The six first-named 

 stars of the third, fourth, and fifth magnitudes were the only 

 ones which could be readily distinguished.^ Of these Ovid 

 says (Fast., iv., 170), 



" Qua? septem dici, sex tamen esse solent." 



One of the daughters of Atlas, Merope, the only one who 

 was wedded to a mortal, was said to have veiled herself for 

 very shame, or even to have wholly disappeared. This is 

 probably the star of about the seventh magnitude, which we 

 call Celseno ; for Hipparchus, in his commentary on Aratus, 

 observes that on clear moonless nights seven stars may ac- 

 tually be seen. Celseno, therefore, must have been seen, for 

 Pleione, which is of equal brightness, is too near to Atlas, a 

 star of the fourth magnitude. 



The little star Alcor, which, according to Triesnecker, is 

 situated in the tail of the Great Bear, at a distance of 11' 



* Hipparchus says (ad Arati Phcen., 1, p. 190, in Uranologio Petavii), 

 in refutation of the assertion of Aratus that there were only six stars 

 visible in the Pleiades : " One star escaped the attention of Aratus. For 

 when the eye is attentively fixed on this constellation on a serene and 

 moonless night, seven stars are visible, and it therefore seems strange 

 that Attalus, in his description of the Pleiades, should have neglected 

 to notice this oversight on the part of Aratus, as though he regarded the 

 statement as correct." Merope is called the invisible (navatpav^) in 

 the Catasterisms (XXIII.) ascribed to Eratosthenes. On a supposed 

 connection between the name of the veiled (the daughter of Atlas) with 

 the geographical myths in the Meropis of Theopompus, as well as with 

 the great Saturnian Continent of' Plutarch and the Atlantis, see my Ex 

 amen Crit. de VHist. de la Giographie, t. i., p. 170. Compare also Ideler 

 Untersuchungen fiber den Ursprung iind die Bedeutung der Slernnamen, 

 1809, p. 145; and in reference to astronomical determination of place 

 consult Madler, Untsrsuch. ubef die Fixstem-Systeme, th. ii., 1848, s. 36 

 and 166; also Baily in the Mem. of the Aslr. Soc, vol. xiii., p. 33. 



