1834.] European Science. 253 



It appears extremely probable tbat those meteors which are observed to move 

 horizontally over extensive portions of the earth's surface would, if watched to the 

 end of their course, be found to terminate this by an explosion and fall of aerolites. 

 It is also probable that the only remaining phenomenon of analogous character, 

 that of falling stars, which may be constantly seen to occur in the field of a large 

 telescope, is a case of precisely the same kind — minute cometary clouds, condensed 

 and burnt into dust by the pressure and oxygen of the atmosphere, with the ex- 

 tinction of light which would follow such condensation and combustion*. 



An apparent exception to the general process of attraction presents itself in the 

 case of a few fixed stars, which are supposed to have been changed into nebulse. 

 It is more probable that no such change has occurred, and that the mistake has 

 happened through the insufficient power of the telescopes of early observers. 



Mr. Airy's paper gives no elucidation of that strange phenomenon, so brilliant 

 in this climate, the zodiacal light, which by its form and position would appear 

 to be a solar atmosphere ; while we know for certain that, if all its parts have the 

 same angular velocity of rotation as the body of the sun, no such atmosphere can 

 extend to such a distance from the sun without being entirely carried away by 

 its centrifugal force. 



Another subject which more comprehensive views could not fail to elucidate is 

 the temperature of the solar system and of the medium which surrounds it. 



Fourier concludes that the temperature of the whole of the planetary space, or 

 rather of the ether which fills it, is about 58° Fahr. But if this ether obey the 

 universal laws of gravitation, as it is reasonable to infer from general principles 

 must be the case, and as the contracted bulk of Entcke's comet, near its perihe- 

 lion, may be said to prove ; moreover, if, as is probable, this ether be highly mo- 

 bile and obedient to the laws of latent heat, its density must be greater in the 

 vicinity of the sun and planets, and each atom of ether in approaching the sun or 

 planets must have its temperature raised by the partial loss of its capacity for 

 heat, and will again lose this heat in moving away from the sun or planets : 

 whence it will follow that the etherial temperature must be higher in the neigh- 

 bourhood of the larger of these bodies, and that Fourier's deduction concerns 

 only that portion of the ether which immediately surrounds the earth's atmosphere. 



If we suppose the whole solar system to have been at its creation endued with 

 the same temperature, and if we consider its members as so many liquid spheroids, 

 subjected to the usual laws of cooling, the largest and rarest masses, and those 

 protected by the largest atmosphere envelopes, retaining their heat the longest ; 

 to have an explanation of the present high temperature of the sun, which with 

 only i of the earth's density has 300,000 times more weight, of the moderated 

 temperature of the earth's surface, of the ice-bound condition of the surface of the 

 moon, which with a greater density than the earth has, only *$ of its weight, and 

 hardly any appreciable atmosphere, and of the apparently fluid condition of the 



* It is a popular belief in some parts of Great Britain that falling stars have been 

 found in a gelatinous form upon the earth's surface ; and from professor Silliman^s 

 Journal, it would appear that the same notion is current in America ; the " sparkling 

 jelly," there described, would form a curious subject for chemical examination ! From 

 the composition of aerolites it would seem that the elementary components of the uni- 

 verse are the same every where, but this singular substance would appear to have no 

 representative in our globe. 



