Mr Galloway on Shooting- Stars and Meteors. 393 



far exceeding those at which the atmosphere can he supposed 

 capable of supporting combustion, it is manifest that their 

 light is not reflected from the sun ; they must therefore be 

 self-luminous, which is contrary to every analogy of the solar 

 system. Fourthly, if masses of solid matter approach so near 

 the earth as many of the shooting-stars do, some of them 

 would inevitably be attracted to it ; but of the thousands of 

 shooting-stars which have been observed, there is no authen- 

 ticated instance of any one having actually reached the earth. 

 Fifthly, instead of the meteors being attracted to the earth, 

 some of them are observed actually to rise upwards, and to 

 describe orbits which are convex towards the earth ; a cir- 

 cumstance of which, on the present hypothesis, it seems dif- 

 ficult to give any rational explanation. 



The most recent hypothesis is that of Capocci of Naples, 

 who regards the aurora borealis, shooting-stars, aerolites, and 

 comets, as having all the same origin, and as resulting from 

 the aggregation of cosmical atoms, brought into union by mag- 

 netic attraction. He supposes that in the planetary spaces 

 there exist bands or zones of nebulous particles, more or less 

 fine, and endued with magnetic forces, which the earth tra- 

 verses in its annual revolution ; that the smallest and most 

 impalpable of these particles are occasionally precipitated on 

 the magnetic poles of our globe, and form polar auroras ; that 

 the particles a degree larger, in which the force of gravitation 

 begins to be manifested, are attracted by the earth and appear 

 as shooting-stars ; that the particles in a more advanced state 

 of concretion give rise in like manner to the phenomena of 

 fire-balls, aerolites, &c. ; that the comets, which are known to 

 have very small masses, are nothing else than the largest of 

 the aerolites, or rather uranolites, which in course of time col- 

 lect a sufficient cmantity of matter to be visible from the earth. 

 This theory of Capocci differs from Chladni's only by the in- 

 troduction of magnetic forces among the particles, and it is 

 obvious that all the objections to the former theory apply with 

 equal force to this. It may be remarked, however, that some 

 physical connexion between the phenomena of shooting-stars 

 and the aurora had been already suspected, and the observations 

 adduced by M. Quetelet afford reason to suppose that the lat- 

 ter phenomenon is also periodical. 



