Ragnarok : the age of fire and gravel

398 CONCLUSIONS.

“ Although few scientific men now question a relationship between comets and the ordinary meteors, there are those, and among them some of our ablest men, who think that the large meteors, or bolides, and aérolites, may be different astronomically, and perhaps physically, from the ordinary shooting-stars, and in the past some contended that they originated in our atmosphere ; others that they were ejected from terrestrial volcanoes. . . . And at the present time the known facts, and all scientific thought, seem to point to the conclusion that the difference between them and ordinary shooting-stars is analogous to that between rain and mist, and, in addition to the reasons already given for connecting them with comets, may be mentioned the fact that meteorites bring with them carbonic acid, which is known to form so prominent a part of comets’ tails; and if fragments of meteoric iron or stone be heated moderately in a vacuum, they yield up gases consisting of oxygen, carbon, hydrogen, and nitrogen, and the spectrum of these gases corresponds to the spectrum of a comet’s coma and tail.

“ By studying their microscopical structure, Mr. Sorby ‘has been able to determine that the material was at one time certainly in a state of fusion ; and that the most remote condition of which we have positive evidence was that of small, detached, melted globules, the formation of which can not be explained in a satisfactory manner, except by supposing that their constituents were originally in the state of vapor, as they now exist in the atmosphere of the sun; and, on the temperature becoming lower, condensed into these “ultimate cosmical particles.” These afterward collected into larger masses, which haye been variously changed by subsequent metamorphic action, and broken up by repeated mutual impact, and often again collected together and solidified. The meteoric irons are probably those portions of the metallic constituents which were separated from the rest by fusion when the metamorphism was carried to that extreme point.’”

But if it be true, as is conceded, that all the planets and comets of the solar system were out-throwings from the sun itself, then all must be as much of one quality of