SHOOTING STARS. 205 



veniber 'pp.riods alone attracted attention, has been increased 

 by recent observations, whose results present a high degi'ce 

 of probability. From the meritorious labors, first of Brandes, 

 Benzenberg, Olbers, and Bessel, subsequently of Erman, Bo- 

 guslawski, Gluetelet, Feldt, Saigey, Edward Heis, and Juhus 

 Schmidt, corresponding measurements have been commenced, 

 and a more generally diffused mathematical spirit has ren^ 

 dered it more difficult, through self-deception, to make uncer- 

 tain observations agree with a preconceived theory. 



The progress in the study of fire-meteors would be so much 

 the quicker in proportion as facts are impartially separated 

 from opinions, and details put to the test ; but not every thing 

 discarded as being imperfectly observed which can not yet be 

 explained. It appears to me most important to separate the 

 'physical relations from the geometrical and numerical rela- 

 tions, which latter are, upon the whole, capable of being es- 

 tablished Avith greater certainty. To this class belong alti- 

 tude, velocity, individuality, and multiplicity, of the points of 

 departure when divergence is detected ; the mean number of 

 fire-meteors in sporadic ox periodic appearances, reduced, ac- 

 cording to their frequency, to the same measure of time ; the 

 magnitude and configuration in connection with the time of 

 year, or with the length of time from midnight. The inves- 

 tigation of both kinds of relations, the physical and the geo- 

 metrical, will gradually lead to one and the same end — to 

 genetic considerations as to the intrinsic nature of the phe- 

 nomenon. 



I have already pointed out the fact that, upon the ivhole, 

 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.=^ A sen- 



* The aspect of the starry heavens presents to us objects o{ unequal 

 date. Much has long ceased to exist before the knowledge of its pres- 

 ence reaches usi much has been otherwise arranged. Cosmos, vol. i., 

 p. 154, and vol. iii., p. 89, and note. (Compare also Bacon, Nov. Organ.^ 

 Lend., 1733, p. 371, andW. Herschel,in Ph%l. Trans, for 1802, p. 498.^ 



