SHOOTING STARS AND Ali:ROLITES. 



39 



consolidated into dense masses^^ (less dense, ' 

 however, than the mean density of the Earth), | 

 then must they form very insignificant nuclei 

 to the fire-balls, surrounded by inflammable va- 

 pours or gases, from the interior of which they 

 shoot, and which, judging from their height and 

 apparent diameters, must have actual diame- 

 ters of from 500 to 2600 feet. The largest me- 

 teoric masses of which we have information, 

 those to wit of Bahia and Otumpa in Chaco, 

 which Rubi de Celis has described, are from 7 

 to 7^ feet in length. The meteoric stone of 

 Aegog Potamos, so celebrated through the 

 whole of antiquity, and which is even mention- 

 ed in the Marble Chronicle of Paris, is described 

 as having been of the magnitude of two mill- 

 stones, and of the weight of a wagon load. 

 Despite the vain attempts of the African trav- 

 eller, Browne, I have not yet abandoned the 

 hope that this great Thracian meteoric stone, 

 which must be so difficult of destruction, though 

 it fell more than 2300 years ago, will again be 

 discovered by one or other of the numerous 

 Europeans who now perambulate the East in 

 safety. The enormous aerolite which fell in 

 the beginning of the 10th century in the river 

 at Narni, projected a whole ell above the sur- 

 face of the water, as we are assured by a doc- 

 ument lately discovered by Pertz. It is to be 

 observed, however, that none of these aerolites, 

 whether of ancient or modern times, can be re- 

 garded as more than principal fragments of the 

 mass which was scattered by the explosion of 

 the fire-ball or murky cloud whence they de- 

 scended. 



When we duly consider the mathematically 

 determined enormous velocities with which 

 meteoric stones fall from the outer confines of 

 our atmosphere to the earth, or with which, as 

 fire-balls, they speed for long distances through 

 even the denser fields of air, it seems to me 

 more than improbable that the metalliferous 

 mass, with its internally disseminated and very 

 perfect crystals of olivine, labrador, and pyrox- 

 ene, could have run together in so short an in- 

 terval into a solid nucleus from any state of gas 

 or vapour. The mass that falls, besides, even 

 in cases where the chemical constitution varies, 

 has always the particular characters of a frag- 

 ment ; it is commonly of a prismatoidal or ir- 

 regular pyramidal form, with somewhat arched 

 surfaces and round edges. But whence this 

 figure, first observed by Schreibers, of a mass 

 detached from a rotating planetary body 1 Uqre, 

 too, as in the circle of organic life, all that has 

 reference to the history of evolution is hidden 

 in obscurity. Meteors begin to lighten and to 

 burn at elevations which we must look upon as 

 almost perfect vacuums, or that cannot contain 

 l-100,000th of oxygen. Biot's new researches 

 on the interesting crepuscular phenomenon(33), 

 reduce the line very notably which, somewhat 

 hardily perhaps, is frequently spoken of as the 

 limits of our atmosphere ; but luminous phe- 

 nomena take place independently of the pres- 

 ence of oxygen, and Poisson has admitted the 

 combustion of aerolites, or meteors, as occur- 

 ring far beyond the confines of our atmosphere. 

 It is only in so far as calculation and geomet- 

 rical admeasurement can be applied to meteor- 

 ic stones, as to the greater bodies of the solar 

 fiystem, that we feel ourselves proceeding on 



surer grounds. Although Halley had already 

 pronounced the great fire-ball of 1686, the mo- 

 tion of which was in opposition to that of ihe 

 earth, a cosmic phenomenon(3*), Chladni was 

 the first (1794) who, in the most general terms, 

 and most clearly recognized the connection be- 

 twixt fire-balls and the stones that fall from the 

 atmosphere, as well as the correspondence be- 

 tween the motions of these bodies and those 

 of the planetary masses at large("). A brill- 

 iant confirmation of this view of the cosmic 

 origin of such phenomena has been supplied by 

 Denison Olmsted, of New-Haven, Connecti- 

 cut, in his observations on the showers of 

 shooting stars and fire-balls which made their 

 appearance in the night from the 12th to the 

 13th of November, 1833. On this occasion, all 

 these bodies proceeded from the same quarter 

 of the heavens — from a point, namely, near the 

 star 7 Leonis, from which they did not deviate, 

 although the star, in the course of the length- 

 ened observation, changed both its apparent 

 elevation and its azimuth. Such an independ- 

 ence of the rotation of the earth proclaimed 

 that the luminous bodies came from without — 

 from outer space into our atmosphere. Accord- 

 ing to Encke's calculations of the entire series 

 of observations that were made in the United 

 States of North America, between the paralells 

 of 35° and 42°, the whole of the shooting stars 

 came from the point in space towards which 

 the earth was moving at the same epoch(^*). 

 In the subsequent American observations on the 

 shooting stars of November 1834 and 1837, and 

 the Bremen ones of 1838, the general parallel- 

 ism of their courses, and the direction of the 

 meteors from the constellation Leo, were per- 

 ceived. As in the November periodical recur- 

 rence of shooting stars, a more decided parallel 

 and particular direction has been noted than in 

 the case of those that appear sporadically at 

 other seasons, so in the August phenomenon it 

 has also been believed that the bodies came for 

 the major part from a point between Perseus 

 and Taurus, the point towards which the earth 

 is tending about the middle of the month of 

 August. This was particularly remarked in 

 the summer of 1839. This peculiarity in the 

 phenomenon of falling stars, the direction of 

 retrograde orbits in the months of November 

 and August, is especially worthy of being either 

 better confirmed or refuted by the most careful 

 observations upon future occasions. 



The altitudes at which shooting stars make 

 their appearance, by which must be understood 

 the periods between their becoming visible and 

 their ceasing to be so, are extremely various ; 

 in a general way, they may be stated as vary- 

 ing between four and thirty-five geographical 

 miles. This important result, as well as the 

 extraordinary velocity of the problematical as- 

 teroids, was first arrived at by Benzenberg and 

 Brandos, by means of a series of contempora- 

 neous observations and determinations of par- 

 allax, at either extremity of a base hne 46,000 

 feet in length("). The relative velocity of the 

 motion was from four and a quarter to nine 

 miles per second ; it was therefore equal to 

 that of the planets(38). such a velocity of 

 movement, as well as the frequently observed 

 course of shooting stars and fire-balls in a di- 

 rection the opposite of that of the earth, lias 



