NOTES TO PRECEDING SECTION. 



113 



These for the fire-ball of Weston (Connecticut, Dec. 14, 

 1807) assign 500, for the one observed by Le Roi (10th July, 

 1771) about 1,000, and for that seen by Sir Charles Biagden 

 (18th Jan. 1783) as many as 2,600 feet in diameter. Brandes 

 (Unterhaitung. Bd. i. S. 42) assig;ns from 80 to 120 feet to 

 shooting stars ; their luminous tails being fntm 3 to 4 miles 

 in length. But there are not wanting optical grounds for 

 believing that the apparent diameter of fire-balls and shoot- 

 ing stars is greatly over-estimated. The volume of fire- 

 balls is certainly not to be compared with the volume of 

 Ceres (even supposing this planet to be no more than 70 

 English miles iu diameter, as has been estimated) : see the 

 accurate and admirable treatise, On the Connexion of the 

 Physical Sciences, 1835, p. 411. I here add in illustration 

 of what has been said at page 39, of the great Aerolite of 

 the bed of the river Narai, the passage from the Chronicon 

 Benedicti, monachi Sancti Andrea in Monte Soracte, which 

 has been referred to by Pertz, a document of the 10th cen- 

 tury, and that is preserved in the Biblioteca Chigi at Rome. 

 The barbarous writing of the time is preserved unaltered : 

 ♦'Anno— 921— temporibus domini Johannis Decimi pape, in 

 anno pontificatus illius 7, visa sunt signa. Nam juxta ur- 

 bem Roman lapides plurimi de coelo cadere visi sunt. In 

 civitate quifi vocatur Narnia tarn diri ac letri, ut nihil aliud 

 credatur, quam de infernalibus locis deducti essent. Nam 

 ita ex illis lapidibus unus omnium maximus est, utdecidens 

 in flumen Nanms, ad mensuram unius cubiti super aquas 

 fluminis usque hodie videretur. Nam et ignitje faculse de 

 cceIo plurimae omnibus in hac civitate Romani populi visie 

 sunt, ita ut pene terra contingeret. Alise cadentes," &c. — 

 (Pertz, Monum. Germ. hist. Scriptores, t. iii. p. 715.) On 

 the Aerolites of Aegos Potamos, whose fall the Pariscan 

 Chronicle states to have happened in the 78-1 Olympiad 

 {Bockh, Corp. Inscr. Grsc. t. ii. p. 302, 320, and 340). 

 Aristot. Meteor. L 7 (Ideler, Comm. t. i. p.404— 407) ; Stob. 

 Eel. Phys. i. 25 p. 508, Heeren ; Plut. Lys. c. 12 ; Diog. 

 Laert. ii. 10. (And also under the Notes 39, 57, 58, and 59. ) 

 According to a MongoHan tradition, a black rocky mass, 40 

 feet in height, is said to have fallen from heaven in a plain 

 near the sources of the Yellow River in Western China. — 

 Abel-R6niusat, in Lam^therie, Journ. de Phys. 1819, Mai, 

 p. 264. 



33 (p, 39.)— Biot, Trait6 d'Astronomie physique, (3me 

 *d.) 1841 t. i. p. 149, 177, 238, and 312. My immortal friend 

 Poisson attempted the solution of the difficulty of sponta- 

 neous combustion occurring in an aerolite in a region where 

 the density of the atmosphere is almost nil, in a very pecu- 

 liar manner. He says, "A une distance de la terre oli la 

 densite de I'atmosphere est tout-^-fait insensible, il serait 

 difficile d'attribuer, coinme on le.fait, I'incandesccnce des 

 aerolithes a uu frottement contre les molecules de Tair. Ne 

 pourrait-on pas supposer que le fluide 61ectrique a I'^tat 

 neutre forme une sorte d'almosphere, qui s'etend beaucoup 

 au-dela de la masse d'air ; qui est soumise A I'attraction de 

 la terre, quoique physiqueraent imponderable; et qui suit, 

 »n consequence, notre globe dans ses mouvements? Dans 

 cette hypothese, les corps dont il s'agit, en entrant dans 

 cette atmosphere imponderable, d^composeraient le fluide 

 neutre, par leur action in^gale sur les deux 61ectricites, ct 

 ce serait en s'electrisant qu'ils s'^chaufferaient et deviendra- 

 ient incandescents." — (Poisson, Rech. sur la Probabilit6 des 

 Jugements, 1837, p. 6.) 



34 (p. 39.)— Philos. Transact, vol. xxix. p. 161—163. 



35 (p. 39.) — The first edition of Chladni's important treat- 

 ise. On the origin of the masses of Iron discovered by Pallas 

 and others, appeared two months before the shower of stones 

 fell at Siena, and two years before Lichtenberg's proposi- 

 tion, " that stones come into our atmosphere from universal 

 space," iu the Gottingen Pocket-Book. — Vide Olbers' Letter 

 to Benzenberg of Nov. 18th, 1837, and the latter's work on 

 Falling Stars, p. 186. 



36 (p. 39.)— Encke, in Poggend. Annalen, Bd. xxxiii. 

 (1834) S. 213. Arago, in Ann. pour 1836, p. 291. Two let- 

 ters of mine to Benzenberg, 19th May and Oct. 22d, 1837, 

 on the supposed precession of the nodes in the orbit of the 

 periodic streams of shooting stars (Benzenb. Sternsch. S, 

 207 and 209). Olbers, too, subsequently came into this 

 opinion of the gradual retardation of the November phenom- 

 enon (Astron. Nachr. 1838, No. 372, S. 180). If I venture 

 to connect two of the falls of shooting stars indicated by the 

 Arabian writers with those discovered by Botruslawski, as 

 having occurred in the 14th century, I obtain the following 

 more or less accordant elements of the nodal movement : 



In October 902, in the night of the death of King Ibrahim- 

 ben- Ahmed, there was a great fall of stars, " like a fiery 

 rain." This year was on this account called the year of the 

 stars. — (Conde. Hist, de la domin. de los Arabes, p. 346.) 



Oct. 19th, 1202.— Stars fell the whole night through; 

 "they fell like locusts." — (Comptes-rendus, 1837, t. i. p. 

 294, and Fraehn, in Bull, de I'Acad. de St. P6tersbourg, t. 

 iii. p. 308.) 



Oct. 21, old style, 1366, die sequente post festum xi. mil- 

 lia Virgiuum ab hora matutina usque ad horam priman visa) 

 sunt quasi steliae de caelo cadere contiiiuo, et in tanta mul- 



titudine, quod nemo narrare sufficit. This remarkable no- 

 tice, of which more use wil' be made further on in the text, 

 was discovered by M.von Boguslawski, Jun. in Benesse (de 

 Ilorowic) de W<?itniil or Weithmiil's Chronicon Ecclesia 

 Pragensis, p. 389. This chronicle is republished in the 2«1 

 part of the Scriptores rerum Bohemicarum von Pelzel und 

 Dobrowsky, 1784 (Schum. Astr. Nachr. Dec. 1839). 



Night of Nov. 9—10, 1787, many shooting stars obsenred 

 by Hemmer in South Germany, particularly in Manheim. 

 — (Kaemtz, Meteorol. iii. 237.) 



Midnight, Nov. 12, 1799.— The extraordinary fall of stars, 

 which Bonpland and I have described, and which was ob- 

 served over the greater part of the globe.— (Vt<ie Relat. 

 Hist. t. i. p. 519—527.) 



Nov. 12—13, 1822, shooting stars mingled with fire-balls, 

 in great numbers, seen by Kloden, in Potsdam (Gilbert't 

 Annalen, vol. 72, p. 291). 



Nov. 13th, 1831, at four a.m., a great fall of stars seen by 

 Captain B^rard on the coast of Spain, near Carthagena del 

 Levante (Annuaire, 1836, p. 297). 



Night of Nov. 12—13, 1833.— The remarkable North 

 American phenomenon so admirably described by Denison 

 Olmsted. 



Night of Nov. 13—14, 1834.— The same phenomenon, bat 

 not so brilliant, observed in North America (PoggendoriF, 

 Ann. Bd. xxxiv. S. 129), 



Nov. 13th, 1835, a stack was set on fire by a single fire- 

 ball near Belley, D6p. de I'Ain (Annuaire, 1836). 



In the year 1838, the stream of shooting stars showed it- 

 self most decidedly in the night from the 13th to the Hth 

 November (Astronom. Nachrichten, 1838, No. 372). 



37 (p. 39.) — It is not unknown to me that of the 62 shoot- 

 ing stars which were simultaneously observed in Silesia, at 

 the instance of Prof. Brandes, some appeared to have had 

 an elevation of 'i^jg> of 60 and even of 100 miles, vide 

 Brandes, Unterhaltungen fiir Freunde der Astronomic und 

 Physik, Heft i. S. 48. But Olbers, by reason of the small- 

 ness of the parallax, regards all determinations above 30 

 miles in height as doubtful. 



38 (p. 39.) — The velocity of^ the planets in their orbits 

 varies greatly ; for Mercury it is 6-6, for Venus 4*8, and for 

 the Earth 4*1 German miles per second. 



39 (p. 40.) — Chladni discovered that an Italian natural 

 philosopher, Paolo Maria Terzago, 1660, on the occasion of 

 a fall of aerolites at Milan, in which a monk was killed, was 

 the first who spoke of the possibility of aerolites being moon- 

 stones : " Labant philosophorum mentes," says he, in his 

 work, Musaeum Septalianum, Manfredi Septalae, Patricii 

 Mediolanensis, industrioso labore constructum, Tortona, 

 1664, p. 44, "sub horum lapidum ponderibus ; ni dicere 

 velimus, lunam terram alteram, sive mundum esse, ex cujus 

 monlibus divisa frustra in inferiorem nostrum hunc orbem 

 delabantur." Without having any knowledge of this con- 

 jecture, Olbers was led in the year 1795, after the great fall 

 of stones that took place at Siena (16th June, 1794), to the 

 inquiry of — how great the original projectile force must be 

 to send masses from the moon to the earth ? And a prob- 

 lem of this kind found occupation for such minds as La- 

 place, Biot, Brandes, and Poisson, for some ten or twelve 

 years. The opinion once very generally entertained, but 

 now abandoned, of the existence of active volcanoes in the 

 moon without atmosphere and without water, favoured in 

 the public mind the confusion of a mathematical possibility 

 with a physical probability — an explanation of a physical 

 fact preferable to other explanations. Olbers, Brandes, and 

 Chladni, believed that they had discovered a refutation 

 of the lunar origin of meteoric stones in the relative velo- 

 city of from 4 to 8 miles, with which fire-balls and shoot- 

 ing stars enter our atmosphere. To reach the earth, ac- 

 cording to Olbers, without bringing the resistance of the 

 air into the reckoning, an original velocity of 7780 feet per 

 second were requisite ; according to Laplace, the necessary 

 velocity is 7377 feet ; according to Biot, 7771 feet ; and ac- 

 cording to Poisson, 7123 feet. Laplace calls this primary 

 velocity only from 5 to 6 times greater than that which a 

 cannon-ball possesses as it leaves the gun ; but Olbers has 

 shown, " that with such a primary velocity of from 7500 to 

 8000 feet per second, meteoric stones would only reach the 

 confines of our atmosphere with a velocity of 35,000 feet" 

 (1*53 German geographical mile). But as the measured 

 velocity of meteoric stones is in the mean 5 geographical 

 miles, or more than 114,000 feet per second, they must ori- 

 ginally have had a centrifugal force in the moon of 110,000 

 feet per second, fourteen times greater therefore than La- 

 place assumes. (Olbers in Schum. Jahrb. 183T, S. 52—58 

 und in Gehler's Nues physik. Woterbuche, Bd. vi. Abth. 

 3, S. 2129—2136.) The absence of any resistance from the 

 air would, however, give the projectile force of the lunar 

 volcanoes an advantage beyond the projectile force of our 

 volcanoes on the earth, supposing always that volcanic ac- 

 tion is conceived as possible in the body of the moon ; but 

 upon the amount or measure of the power of these lunar 

 volcanoes, we are still without any information. It is very 



