SHOOTING STARS. 567 



to separate the physical relations from the geometrical and 

 numerical relations, which latter are upon the whole capable 

 of being established with greater certainty. To this class 

 belong altitude, velocity, individuality, and multiplicity, of 

 the points of departure when divergence is detected; the 

 mean number of fire-meteors in sporadic or periodic appear- 

 ances reduced according to their frequency to the same 

 measure of time, the magnitude and configuration in con- 

 nection with the time of year, or with the length of time 

 from midnight. The investigation of both kinds of relations, 

 the physical and the geometrical, will gradually lead to one 

 and the same end, to genetic considerations as to the intrinsic 

 nature of the phenomenon. 



I have already pointed out the fact that, upon tlie whole^ 

 intercourse with universal space and its contents is restricted 

 to that which we acquire through oscillations exciting light 

 and heat, as well as by the mysterious attractive forces which 

 remote masses (cosmical bodies) exercise upon our terrestrial 

 globe, its oceans and atmospheric envelope, according to the 

 quantity of their material particles. The luminous vibra- 

 tions which proceed from the smallest telescopic stars of a 

 resolvable nebula, and of which our eyes are sensible, brings 

 us a testimony of the oldest existence of matter in the same 

 way that it mathematically demonstrates to us the certain 

 knowledge of the velocity and aberration of light. 1 A sensa- 

 tion of light from the depths of the star-filled space of heaven 



1 The aspect of the starry heavens presents to us objects of 

 unequal date. Much has long ceased to exist before the 

 knowledge of its presence reaches us ; much has been other- 

 wise arranged. Cosmos, vol. i. p. 144, and vol. iii. p. 90, 

 and note. (Compare also Bacon, Nov. Organ. Lond. 1733, 

 p. 371, and Will. Hersche!, in the Philos. Transact, for 

 1802, p. 498.) 



