A CATALOGUE OF OBSERVATIONS OF LUMINOUS METEORS. 141 



results of the " uniqueness and peculiarity of the position, powers, and functions of 

 the Sun, as the physical centre of the solar system," is, that such conditions must in 

 the nature of things have heen from the beginning, and must ever be, confined to 

 it and its immediate vicinity ; that they never have existed, and cannot exist, any- 

 where else in the solar system, or in the space which it now occupies. Of the pre- 

 sence of the conditions requisite for the genesis of meteorites within, upon, and 

 immediately around the Sim, we have actual and ample evidence, quite independent 

 of that which may be derivable from meteorites themselves. But all that can be 

 said in support of the notion that such conditions could ever extend to distances 

 from the Sun comparable to those of the planets, is to adduce the very facts to 

 account for which that notion is brought forward, or refer to what are supposed to 

 be the probabilities of the "nebular hypothesis" hitherto unverified. 



I deem myself justified in affirming that Mr. Sorby, by his microscopical obser- 

 vations of the structure of meteorites, has verified the hypothesis of their origin 

 and formation which has been stated in my " Inferences and Suggestions " through 

 a great part of their genetic history, — to the extent that is, of their condensation 

 from separate volumes or masses (believed to be originally solar bubbles) of aeriform 

 matter, consisting of the mingled vapours of their chemical elements, at a very high 

 temperature, in intense commotion, and existing, or having existed, in planetary 

 space somewhere between the Sun and the Earth*. 



The second most important residt of Mr. Sorby's investigation, is that many 

 meteorites have been subjected to a metamorphic action. 



" The particles of the cometary cloud," he saj r s, " moving with great velocity, 

 were often broken by collision. After collecting together to form larger masses, 

 heat, generated by mutual impact, or that existing in other parts of space through 

 which they moved, gave rise to a sensible amount of metainorphism. In some few 

 cases, when the whole mass was fused, all evidence of a previous history has been 

 obliterated ; and on solidification a structure has been produced quite similar to 

 that of terrestrial volcanic rocks." 



The basaltic character of meteoric stones which Dr. Haidinger and Mr. A. S. Her- 

 schel have adduced in support of their conclusion, that they must have been frag- 

 mentsof true planets previously existing, together with the mineral constitution which 

 has led the former inquirer as well as Mr. R. P. Greg to regard them as unerupled 

 lavas, are manifestly the results of the metamoi-phism which some have undergone, 

 for the discovery of which, thus annoimced, science is indebted to Mr. Sorby. That 

 while existing as meteoritic masses resulting from the condensation of solar bub- 

 bles and froth, and prior to their coalescence into planetary bodies, or becoming 

 the nuclei of meteors, meteorites had undergone metamorphism, or that any which 

 had actually fallen upon the Earth had suffered that process, had never occurred to 

 me ; although I had been indebted to Mr. Sorby's kindness and liberality for an 

 opportunity of examining his series of sections of meteorites prepared for the mi- 

 croscope, before my paper was communicated to the Royal Society. This discovery 

 has removed an ambiguity, which from the time when the resemblance of certain 

 meteorites to volcanic rocks was distinctly recognized, has led to continued misap- 

 prehension of the nature of meteorites in general, and of their genetic history. 

 From this I had been myself preserved only by the conviction, that a group or 

 series of mineral aggregates possessing the unique character that nearly alf its 

 terms, even those principally composed of oxides, contained iron in the metallic 

 state, while some were entirely devoid of oxygen, consisting exclusively of iron 

 and other metals, together with uncombined "carbon, and also sidphur and phos- 

 phorus (if not silicon) united merely with portions of those metals, could not have 

 had the same origin with another group, volcanic rocks, which are character- 

 istically the results of oxidation, all their proximate constituents being oxides, 

 whether simple or compound. It was as evident at least that certain meteoric rocks 

 were genetically independent of the presence of oxygen, as that all volcanic rocks 

 were essentially due to its action ; while the meteorites devoid of oxygen were mani- 



* The four paragraphs which terminate here have already appeared in an article on the 

 physical constitution and functions of the Sun, in the ' Companion to the Almanac ' for 

 1866, in sequence of two others contained in the same work for the two preceding years. 

 In the same article are some further considerations (also derived from my privately printed 

 paper) relative to the meteoritic constitution and physical circumstances of the Zodiacal 

 Light. 



