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of Bergman, Kadner, and Lambert, ihc northern lights 

 have an altitude of more than 20 or 30 German miks, and 

 according to everv appearance, no fire balls have been feen 

 higher. (See Aur ra Borealis.) On the other hand, 

 this general conclufion led Halley, Franklin, and Ritten- 

 houfe, to adopt the notion ingenioufly defended by Chladni, 

 that thefe phenomena, as well as (hooting ftars, are cofmi- 

 cal meteors belonging to the atmofphcre of the fun, which, 

 meeting our eirth in its courfe round that luminary, are in- 

 flamed, by fome caufe or other, when they enter the earth's 

 atmofphere. The time of their duration has been very dif- 

 ferent ; fome of thtm having continued half an hour, and 

 others not longer than half a minute. Many of them in 

 their courfe have thrown out fparks, and mod of them have 

 been feen to feparate into feveral larger and fmailer parts be- 

 fore they entirely difappearcd. From this divifion it has 

 been inferred, that thcfe phenomena cannot be accounted 

 for by the hypothcfis of a traft of inflammable air fet on 

 fire ; to which hypothcfis Chladni has objefted on other 

 grounds. This feparation has been accompanied with a 

 rumbling noifc like thunder, or a fudden report. Several, 

 after burlling, feemed to diffolve into fmoke ; but mod of 

 them, after exploding, have left behind them no vifiblc 

 traces. In fome cafes, after their difappearance, a fulphu- 

 reous fmell has been perceived, which led Mufclienbroeck to 

 form his hypotheCs of an accumulation of fulphureous in- 

 flammable vapours that arife from volcanoes and fubterranean 

 pits, which, being driven together by the winds, form clouds 

 that are by fome accident or other fet on fire ; but this hy- 

 pothcfis cannot be reconciled with their prodigious height 

 any more than that of Silberfchlag's oily and flimy vapours. 

 As fcoriaceous maffes have frequently been either aftually 

 feen to fall at the time of the difappearance of thefe pheno- 

 mena, or have been foon aft-r found on the furface of the 

 earth ; and as it has been fufSciently proved by various ac- 

 counfi, that ftones have fallen from the atmofphere. Dr. 

 Chladni concludes, that both thefe phenomena are con- 

 nefted ; but this point can be determined only by future ac- 

 curate obfervations. 



This ingenious profcfior of Wittenberg, in his " Obfer- 

 vations on a Mafs of Iron found in Siberia by Profcffor Pal- 

 las, &c." has inveftigatcd the origin of fire-balls in general. 

 This mafs, defcribed by Pallas in his " Travels," vol. iii. 

 p. 3ti. was found between Krafnojarflc and Abekanflf, 

 in the high fiate mountains, open and uncovered. It weighed 

 1600 pounds ; refembled in figure a rough granite ; was co- 

 Tcred externally with a ferruginous kind of cruil ; and with- 

 in confifted of malleable iron, brittle when heated, porous 

 like a large fea fponge, and having its interllices filled with 

 a brittle hard vitrified fubftance of an amber yellow colour. 

 This texture and the vitriiied fubftance appeared uniformly 

 throughout the whole mafs, and without any traces of flag or 

 artificial fire. This mafs, which the Tartars confider as a fa- 

 cred rehc dropped from heaven, Chladni refers to the fame on- 

 gin, and fuppofes to be of the fame rtature %vith the bolides, 

 or fire-balls. From a variety of obfervations relating to tliefe 

 phenomena, he endeavours to prove that they do not arife 

 from an accumulation of the matter of the aurora borealis ; 

 a tranfition of eleAricity from one part oi the atmofphere to 

 another; an accumulation of porous inflammable fubdances 

 in the higher regions ; or the catching fire of a long train of 

 inflammable air ; but that their component parts muft be 

 confiderably denfe and heavy, as their courfe fiiews in fo 

 apparent a manner the effects of gravity ; and becaufe their 

 mafs, though it diftends to a monllrous fize, retains fufti- 

 eicnt confillency and weight to continue an e7.»ecdi;igly 



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rapid movement through a very large fpace, without bein^ 

 decompofed or diffolved, not with ftandnig the refiftance of 

 the atmofphcre. It feems to him probable, that this fub- 

 ftance is by the effetl of fire reduced to a tough fluid con- 

 dition ; becaufe its form appears iometimes round and fome- 

 timcs elongated, and as its extending till it burlls, as wcU 

 as the hurtling itfclf, allows us to fuppofe a previous capa- 

 bility of extenfion by elallic fluidity. At a':y rati, it ap- 

 pears to be certain, that fuch denfe matter at fo great S 

 height is not coUefted from particles to be found in our at- 

 mofphcre, or can be thrown together into large maffes by 

 any power with which we are acquainted ; that no power 

 with which we are acquainted is able to give to fuch bodies 

 fo rapid a projectile force in a diretlion almoll parallel to 

 the horizon ; t'>at the matter does not rife upwards from the 

 earth, but exifts previoufly in the cclcftial regions, and muft 

 have been conveyed thence to our earth. In tiie opinion ot 

 Dr. Chladni, the following is the only theory of this phe- 

 nomenon that agrees with all the accounts hitherto given ; 

 which is not Co traiy to nature in any other rtfpcft ; and 

 which befides feems to be confirmed by various malTes found 

 on the fpot where they fell. 



As earthy, metallic and other particles form the principal 

 com.ponent parts of our planets, among which iron is the 

 prevailing part, other planetar\' bodies may therefoie con- 

 iitl of fimilar, or perhaps the fame component parts, though 

 combined and modified in a very different manner. T' ere 

 may alfo be denfe matters accumulated in Imailer maflTes 

 without being in immediate conn.£lion with the larger pla- 

 netary bodies, difperfcd through infinite fpacc, and which, 

 being impelled either by fome projecting power or attraftion, 

 continue to move until they approach the earth or fnnis 

 other body ; when being overcome by their attractive force, 

 they immediately fall down. By tneir exceedinglv great 

 velocity, ftill increaled by the attraftton of the earth, ar.i 

 the violent friction in the atmofphere, a llrong clc**ricity 

 and heat mull necelfarily be excited, by which means the/ 

 are reduced to a flaming and melted condition, and great 

 quantities of vapour and different kinds of gafes are tl'us 

 difengagcd, which diftend the hquid mafs to a monftrous 

 fize, till by a ftill farther expanfion ot thefe elaftic fluids, they 

 maft at length burft. Dr. Chladni thinks alio, that the 

 greater part of the (hooting (lars, as they are called, are 

 nothing elfe than fire-balls, which differ from the latter 

 only in this, that their peculiarly great velocity carries them 

 pall the earth at a greater dillance. fo that thev are not 

 fo llrongly attracted by it as to fall down, and therefore in 

 their paffage through the high regions of the atmofphere, 

 occafion only a tranficnt eleftric flalh, or actually take fire 

 for a moment, ar.d are again fpeedily extinguilhed, when 

 they get to fuch a dillance from the earth that the air be- 

 comes too much rarefied for the exillence of fire. The pro- 

 feffor iliullrates and vindicates this theory, romantic, as hs 

 allows, fome may be difpofed to denominate it, by a variety 

 of refleclions ; and in feme fubiequent publications, he has 

 endeavoured to confirm it by adducing a great number of 

 other phenoinena of a fimilar kind. He concludes the 

 whole elaborate detail with obferving, that the accounts 

 of (coriaceous malfes, which contained iron, earth, fulphur, 

 &c. having fallen from the heavens, with violent explofions, 

 are not firtions, but true relations of real natural phenomena 

 aftually obferved at various times ; and that fire-balls, and 

 the falling of fuch maffes, are the fame meteor. " Refpec- 

 ting the qiieftion," he fays, " whence fire balls and luch 

 fallen mafles proceed, opinions are very different. Mofl 

 people telieve tliat they are owing to accumulations in the 



atmo- 



