SHOOTING STAES. 571 



upon our earth, in the doctrines of the old Ionic schools, from 

 Thales and Hippocrates to Empedocles. 7 The impression 

 made by the occurrence of nature in the 78th Olympiad, 

 appears to have powerfully called forth the idea of the fall of 

 dark masses. In the more recent Pseudo-Plutarch, (Plac. ii. 

 13,) we read merely that the Milesian Thales considered -all 

 stars to be earthy andjfery bodies (750;^ KOI e/jnrvpa)." The 

 endeavours of the earlier Ionic physiology were directed to 

 the discovery of the primitive cause of all things, formation 

 by mixture, gradational change and transition of one kind of 

 matter into another : to the processes of genetic development 

 by solidification or dilution. .The revolution of the sphere of 

 the heavens *' which holds the Earth firmly in the centre," was 

 already conceived by Empedocles as an actively moving cos- 

 mical force. Since, in these first attempts at physical theories, 

 the ether, the fire-air (and indeed fire itself), represents the 

 expansive force of heat, so the idea of the propelling revolu- 

 tion rending fragments from the Earth, became connected 

 with the lofty region of the ether. Therefore Aristotle calls 

 (JLTeteorol. i. 339, Bekker) the ether " the eternally moving 

 body,' 9 as it were the immediate substratum of motion; and 

 seeks for etymological reasons for this assertion. On this ac- 

 count we find in the biography of Lysander, "that the relaxa- 

 tion of the centrifugal force causes the fall of celestial bodies " 

 as also in another place, where Plutarch, evidently alluding 

 again to opinions of Anaxagoras, or Diogenes of Apollonia (De 

 facie in orbe Lunce, pp. 9-23), puts forward the assertion '* that 



7 With regard to absolutely dark cosmical bodies, or such 

 in which the light-process ceases (periodically ?) ; as to the 

 opinions of moderns (Laplace and Bessel) ; and Bessel's obser- 

 vation, confirmed by Peters in Konigsberg, of a variability of 

 Uh& proper motion of Procyon : see Cosmos, vol. iii. pp. 222, 225. 



* Compare Cosmos, vol. iii. pp. 35-39. 



