A CATALOGUE OF OBSERVATIONS OF LUMINOUS METEORS. 133 



Solar spots" are considered. The energy arising from the transition from im- 

 ponderable into ponderable matter, will in part become, it is here said, the 

 centrifugal or projectile force by which the torrents of matter (finally assum- 

 ing the gaseous form) so produced, are impelled through the denser envelopes 

 of the Sun, causing the spots and the other phenomena of ebullition of which 

 the photosphere is the scene. 



The next subjects of discussion are 



The Origin of Meteorites, Series of Physical Processes of which they are the 

 result, and their Functions in Nature. 



The vapours of metallic and other elementary matter evolved or discharged in 

 the ebullition of the photosphere of the Sun, partly remain upon the Sun, consti- 

 tuting its atmospheres*, but are principally aggregated into masses of immense 

 magnitude (terrestrially speaking), of the nature of bubbles. Having undergone 

 a certain amount of condensation, these first become visible to us as those particles 

 the collective brighness of which reveals to us the existence of the zodiacal light, 

 and are, in fact, the matter separated from the Sun's equator by rotation. These 



Jiarticles, termed by the author meteoritic masses, are projected from the zodiacal 

 ight by the force to which its variable extension is owing, and are further gradually 

 condensed during their passage through the interplanetary spaces into the liquid 

 and solid state, constituting eventually the nuclei of meteors, which are finally 

 precipitated upon the Earth (and doubtless upon the other planets) in the form of 

 Meteorites. 



The sudden outburst of light over a solar spot, witnessed on September 1, 1859, 

 by Mr. Carrington and Mr. Hodgson, the author regards as a fact confirmatory of 

 this view, and as having been the consequence or accompaniment of the produc- 

 tion, and the transfer with immense rapidity from within to without some exterior 

 region of the Sun, of a meteoritic mass, or more probably of an immense congeries 

 of such masses, enabled by its consisting of ponderable matter to manifest the 

 higher temperature and consequent greater effulgence of the interior regions of the 

 luminary, whence it was originally derived. Certain phenomena before recorded 

 by astronomers, but not yet understood, are probably of the same nature. 



The structural characters of meteorites are those of bodies which have been origi- 

 nally condensed from heterogeneous vapours — the mingled vapours of uncombined 

 elementary substances variable in their nature, and requiring different temperatures 

 for their maintenance in the gaseous form, but all existing originally at a very high 

 temperature ; and their adequate investigation may afford, as an experimentum 

 crucis, an independent confirmation of Kirchhoff's discovery, and of the truth of 

 the spectrum-analysis of the composition of bodies distant from us in space. They 

 consist, mineralogically, of two groups, meteoric iron and meteoric stones, forming, 

 however, by graduation into each other, as first pointed out by the author many 

 years since, one series of bodies \. The intermediate examples, and indeed most 

 of the stones, are aggregates of earthy matter partly in the crystalline and partly 

 (as Mr. H. G. Sorby has shown J) in the vitreous state, and distinct portions of 

 metallic iron alloyed with other metals. They are, in fact, always heterogeneous 

 aggregates, in conformity with the origin here assigned to them. While, as a 

 class, meteorites are perfectly distinct from all terrestrial rocks — the presence of 

 metallic iron as a mineral constituent imparting to them, indeed, a character which 

 is perfectly unique— some of their constituent minerals, and all the elementary 

 substances of which they are composed, are such as are found, but differently asso- 

 ciated, in the Earth's crust, although there are many other terrestrial elements 

 which have not yet been discovered in them. 



"Ten, or perhaps more, of the elements of the solar atmosphere," according to 

 Kirchhoff and Angstrom, " are also those of meteorites— iron, nickel, cobalt, chro- 

 mium, and magnesium being characteristically such. But the non-metallic base 



* Companion to the Almanac for 1864, p. 46; for 1865, p. 53. 



t Annals of Philosophy (January 1824), second series, vol. vii. p. 73; Philosophical 

 Magazine (December 1841), third series, vol. xix. p. 501. 



\ Proc. Eoy. Soc, vol. xiii. p. 333. Article V. (7) of this Appendix. 



