METEOR, in physiology, a moveable igneous body, congregated in the air by means not thoroughly understood, and varying greatly in size and rapidity of motion. Many attempts have been and are still made to account for the forma tion and ignition of these grand objects. Dr. Woodward, of the old school, seems to have approached nearer to modern opinions, founded on recent observa tions, than any other writer on the sub ject. That gentleman supposed them to originate from mineral particles raised from the earth by subterraneous beat, accompanied by vapours from the same strata which furnished the minerals, and being condensed by the pressure of the atmosphere, partake of the immediate action of the bodies they intersect in their passage. Derham thought the ignis fatuus a vapour on fire ; Beccaria, on the contrary, supposed them to be vapour forced out of the earth by the descent of rain or snow, and not decidedly burning, but rather of the nature of cold phospho ri. Franklin conjectures, in the Memoirs of the Manchester Society, that the dense fog of 1783, may have been produced by smoke, arising from the combustion of some of those vast globes, "which we happen to meet with in our rapid course round the sun." The generality of the meteors observed resemble each other, except in size, which cannot be ascer tained with certainty, on account of the apparent diminution of bodies through distance. The most remarkable of late times were those of 1783 and 1805: the former was very luminous, and its sup posed diameter one thousand yards: the latter passed with such astonishing rapi dity, that amazement had not subsided ere it vanished, consequently very little dependence can bs placed on what has been said concerning its bulk and shape; the light which it emitted was a pale blue, and almost as instantaneous as a flash of lightning, and the rushing of the enormous body produced a sound like very distant thunder. Some of the smaller meteors explode after a certain interval of burning, and it has been uni formly asserted that they deposited stones ; the apparent improbability of this assertion long prevented persons of en lightened minds from crediting it, and till Dr Chladni published a dissertation on the subject in 1794, which induced Mr.
Ring to collect every instance, ancient and modern, calculated to establish the fact with the public, and this was no easy Wk. Mr. Howard followed the example of those two gentlemen; but went fur ther, and actually procured specimens of the substances alluded to, which, having compared, he proceeded to analyze by chemical means. He found them entire ly different from all known stones, and exactly resembling each other, even in their component parts.
It has been said that the stones, thus incontestibly proved by different authori ties, and from various places, to have fallen after the explosion of meteors, are heated and luminous when they reach the earth : the force of their descent buries them some depth into it, and they have been seen under these circumstan ces in Italy, Germany, France, England, and India. The meteors either really do, or appear to, move horizontally, and are said to descend ere they explode. The stones are of different sizes, and from a few ounces in weight to several tons: they are generally circular, and invariably covered with a rough black crust, which, according to Howard, is principally com posed of oxide of iron. The process adopted by that gentleman produced a reslilt, which has since been confirmed by Klaproth and Vauquelin. We shall give the analysis sf two of these substan ces, by Howard, of a stone which fell in Yorkshire ; and by Vauquelin and Four croy, of another that fell at Laigle, in France, 1803 Mr. Howard found that 150grains con tained 75 Silica 37 Magnesia 48 Oxide of iron 2 Oxide of nickel 162 CZ= The oxydizement of the metallic bodies caused this increase of weight. Messrs. Vauquelin and Fourcroy found the mass they examined contained 54 Silica 36 Oxide of iron 9 Magnesia 3 Oxide of nickel 2 Sulphur 1 Lime 5 The conjectures which these extraor dinary productions have occasioned are visionary in the extreme : indeed, M. La-. place' supposes them to be fragments ejected by volcanoes in the moon : Sir William Hamilton and Mr. King, on the contrary, imagine that they are concre tions formed in the atmosphere.