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2. The stony bodies when found are always hot. They com. mouly bury themselves some depth under ground. Their size differs from a very few ounces to several tons. They are usually roundish, and always covered with a black crust. In many cases they smell strongly of sulphur. The black crust, from the analysis of Howard, consists chiefly of oxide of iron.
3. The outer surface of these stones is rough. When broken, they appear of an ash-grey colour, and of a granular texture like a coarse sandstone. When examined with a microscope, four different substances may be discovered of which the stone is composed : Ist, A number of spherical bodies, varying in size from a pin-head to a pea of a greyish.browy colour, opaque, breaking easily in every direction, of a compact texture, capable of scratching glass, and of giving a few feeble sparks with steel. 2d, Frag. ments of pyrites of an indeterminate shape, of a reddish-yellow colour, granular, and easily reduced to powder. The powder has a black colour. 3d, Grains of iron in the metallic state, scattered like the pyrites through the stone. 4th, The three substances just mentioned are cemented together by a fourth of an earthy consist. ence, and so soft that all the other substances may be easily separated by the point of a knife or the pail, and the stone itself crumbled to pieces between the fingers. This cement is of a grey colour. The proportion and size of these different constituents vary considerably in different specimens; but all of them bear a striking resemblance to each other. Their specific gravity varies from 3•352 to 4.281 t.
4. From the analysis of Howard, which was conducted with much precision and address, and which has been fully confirmed by Vauquelin and Klaproth, we learu that the black crust consists of a compound of iron and vickel, partly metallic, and partly oxidized. The pyrites consist of iron, nickel, and“ sulphur. The metallic
grains consist of iron, combined with about 1.3d of its weight of • nickel, and the yellow globules are composed of silica, magnesia,
iron, and nickel. The Count Bournon observes, that these globules resemble the chrysolite of Werner, and that their chemical analysis corresponds exactly with Klaproth's analysis of that mine. ral. The earthy cement consists of the very same substances, and
• Bournon, Phil. Trans. 1809.
nearly in the same proportion as the globular substances. But it will be necessary to exhibit a specimen of some of the analyses, as published by the philosophers to whom we are indebted for them. A stone which fell at Benares in India was analysed by Howard. The pyrites consisted of
The spherical bodies 50.0 silica
The earily cement 48•0 silica
A stone which fell in Yorkshire, deprived as much as possible of its metallic particles, gave Mr. Howard from
The increase of weight was owing to the oxidizement of the metal. lic bodies.
Stones which fell at Laigle in France, in 1803, yielded, by the analyses of Vauqueliu and Fourcroy,
The following Table exhibits the result of the most remarkable analyses of such stones, which have been made since the publica. tion of Howard's paper on the subject.
5. The experiments of Howard, thus confirmed by others, and supported by the most respectable historical evidence, having de. monstrated that these stony bodies really do fal! from the heavens, it was natural to expect that various attempts would be made to accouot for their appearance. But such is the obscurity of the subject, so little progress have we made in the science of meteorology, that no opinion in the slightest degree probable lias hitherto
+ Phil. Mag. xvi. 302.
Klaproth, Gehlen's Jour. i. 8. The stone fell at Sienna, in 1794.
Laugier, luid iv. 331. The stone fell at Vaucluse in 1804. See a descrip. tion of it by Vanquelin, Ann. de Chim. xlviii. 225.
9 Proust, Jour. de Phys. 1x, 185. The stone fell at Sigena, in 1773.
been advanced. It was first supposed that the bodies in question had been thrown out of volcanoes; but the immense distance from all volcanoes at which they have been found, and the absence of all similar stones from volcanic productions, render this opinion untenable. Chladni endeavoured to prove that the meteors from which they fell were bodies Aoating in space, unconnected with auy planetary system, attracted by the earth in their progress, and kindled by their rapid motion through the atmosphere. But this opinion is not susceptible of any direct evidence, and can scarcely be believed, one would think, even by Dr. Chladni bimself. La Place suggests the probability of their having been throwu off by the volcanoes of the moon : But the meteors wbich almost always ac. company them, and the swittuess of their horizontal motion, militate too strongly against this opinion. The greatest number of philosopbers consider them, with Mr. King and Sir William Hamil. ton, as concretions actually formed in the atmosphere. This opinion is undoubtedly the most pro' able of all; but in the present state of our knowledge, it would be absurd to attempt any explanation of the manner in which they are förmed. The masses of native iron found in South America, in Siberia, and near Aynam, contaiu nickel, as bas been ascertained by Proust, Howard, and Klaproth, and resemble exactly the iron found in the stones fallen from the atmosphere. We have every reason therefore to ascribe to thein the same original : aud this accordingly is almost the uniform opinion of philosophers. Klaproth bath shown that real native iron is distinguished froin meteoric iron by the absence of nickel.
[Good's Lucretius. Thomson's Chemistry. 2. Lunar or Selenitic Origin of Meteoric Stones. The best and fullest examination which has yet occurred to us upon this curious subject, is contained in a long and interesting original note of the Editors of the “ Philosophical Transactions Abridged," appended to Dr. Halley's paper on Meteors, or lights
• Geblen's Jour. i. 8.
This closing remark is a strong proof of the difference between the two, and the article which immediately follows is sufficient to show that the ingenious chemist is in an error, in conceiving that the hypothesis to which he seems to incline is “almost the uniform opinion of philosophers."
in the sky, published in vol. xxix. of the Transactions at large. The note is as follows:
Dr. Halley's mind fixes on nothing but vapour or exhalations, to solve the appearance; though the difficulty, not to say impossi. bility, of conceiving how any exhalations could be raised so high, ought to have hinted the idea of some other origin. Later obser. vations however have induced a belief, that these luminous appear. ances are allied to, if not the same as, the stones which have fre. quently been known to fall from the atmosphere, at different times, and in all parts of the earth. Several of the phænomena are common to both. These luminous bodies are seen to move with very great velocities, in oblique directions descending; com. monly with a loud hissing voise, resembling that of a mortar shell, or cannon ball, or rather that of an irregular hard mass projected violently through the air ; surrounded by a blaze or flame, taper. ing off to a narrow stream in the hioder part of it; are heard to explode or burst, and seen to fly in pieces, the larger parts going foremost, and the smaller following in succession; are thus seen to fall on the earth, and strike it with great violence; that on exa. mining the place of the fall, the parts are found scattered about, being still considerably warm, and most of them entered the earth several inches deep. After so many facts and concurring circumstances, it is difficult to refuse assent to the identity of the two phänomena: indeed it seems now not to be doubted, but generally acquiesced in. And hence it is concluded, that every such meteor. like appearance is attended by the fall of a stone, or of stones, though we do not always see the place of the fall, nor discover the stones,
This conclusion, however, has contributed nothing towards dis. covering the origin of the phenomenon, at least as to its genera tion in the atmosphere : on the contrary, it seems still more diffi. cult to accouut for the production of stones, than gaseous meteors, in the atmosphere, as well as to inflame and give them such violent motion. In fact, it seems concluded as a thing impossible to be done, or conceived ; and philosophers have given up the idea as hopeless. This circumstance has induced them to endeavour to discover some other cause or origin for these phænomena. But no idea that is probable, or even possible, has yet been started; excepting one, by the very celebrated mathematician La Place, and