120 RESEARCHES CONCERNING THE PERIODICAL 



observations. The chemical objection is not very weighty, for we may as well 

 suppose a uniformity of constituents in cosmical as in lunar substances. 



The opinion of Arago is contained in the following extract from Quetelet :" 

 "Brandes avait soigneusement appele I'attention sur I'apparition remarquable 

 des meteores qui se montrerent pendant la nuit du 10 Aout, 1S23, mais il avait 

 perdu de vue que le meme phenomene s'etait deja presente, a lui, a la meme 

 epoque, en I'annee 1799. La supposition d'un retour periodique pour ces sortes 

 de phenomenes, ne pouvait guere naitre du reste qu'en presence de faits plus 

 energiquement prononces. II fallait le magnifique spectacle que deploya le 

 nuit du 11 au 12 Novembre, 1832, pour reveiller la curiosite des savants et 

 pour rappeler le souvenir efface du phenomene tout aussi extraordinaire du 11 

 au 12 Novembre, 1799. Le hasard, on pourrait dire, plutot que des combi- 

 naisons scientifiques, amena a constater un fait qui assure desormais aux etoiles 

 filantes un rang si important dans notre systeme planetaire. Ainsi se conjirme 

 de plus en plus, comme le remarquait M. Arago, V existence d'un zone composee 

 de millions de petits corps, dont les orbites rencontrent le plan de Vecliptique vers 

 le point que la terre va occuper tous les ans du 11 au IS Novembre. C'est un 

 nouveau monde planetaire qui commence a se reveler a nous.'' 



That of Olbers is translated from his paper in Schumacher's Jahrbuch for 

 1837, pp. 279 and 280. " Perhaps the phenomenon of 1799 and 1833 has not 

 been renewed. It appears, nevertheless, that a great multitude of the small 

 molecules that compose the shooting stars move round the sun in orbits that 

 intersect the plane of the earth's orbit, especially between the 19th and 21st 

 degree of Taurus. These orbits, very close to each other, and completely 

 parallel, compose, as it were, a common path for myriads, nay millions of these 

 very small asteroids, which, in intervals nearly common, perhaps of five or six 

 years, finish their circuit round the sun. They also seem to be quite une- 

 qually portioned out in this common path, sometimes in thick swarms, some- 

 times more widely separated. In 1799 and 1833, and, perhaps, in 1832, the 

 earth passed through one of these thickest swarms. In 1831, 1834, and 1836, 

 only isolated, though numerous meteoric asteroids were met. Perhaps there 

 are many of these thick swarms moving in this common path; perhaps, also, 

 the inhabitants of the earth must wait till 1867, before they see this wonderful 



''' Catalogue, &c., p. 4. 



