Dr, Reynolds on Meteors- 271 



ors in the following manner, viz. the latent heat on escaping 

 will manifest itself in the form of fire and light, the force with 

 which it strikes the atmosphere, or the rebound of the latter to 

 fill the vacuum, or both, will occasion sound more or less de- 

 tonating or hissing, as the escape is more sudden, or the at- 

 mosphere more dense ; the earthy and metallic particles on the 

 escape of caloric, will obey the laws of cohesive attraction, 

 clash together, recover their gravity, and descend to the earth 

 in masses, or shattered fragments. 



Meteoric stones frequently bear the marks of violence, which 

 is doubtless owing to the conflict sustained at the moment of 

 explosion ; their difference in size depends on the difference 

 of magnitude in the disploding volumes ; something like regu- 

 lar arrangement is frequently perceived in the structure of 

 these stones, because in all productions of sofid from fluid 

 matter, the consolidating particles possess a tendency to arrange 

 themselves in the order of their affinities. It is thus the va- 

 rious arrangements in saline crystallization, the freezing of 

 water, and cooling of melted metals, may be accounted for. 

 There is a real, as well as an apparent difference in the velo- 

 city of meteoric bodies ; the first arising from their difference 

 of magnitude and the violence of the explosion, as well as from 

 the resistance they meet ; the latter, from the different distan- 

 ces at which they are seen. The gradation of colour, from a 

 bright silvery hue to a dusky red, is owing, in a certain degree, 

 to the state of the atmosphere refracting different coloured 

 rays, and also to the materials in the compound, similar to the 

 different hues in artificial fireworks. Reddish and white nebi- 

 cula are sometimes left in the tracks of meteors, which are 

 nothing but ignited vapours, or the particles brushed off the 

 burning body by the resisting atmosphere. The velocity or 

 motion and direction of meteors, depend upon principles well 

 known and daily practised by engineers, and the constructors 

 of fireworks. 



The immediate cause of these explosions is a little obscure, 

 and merits a fuller detail than is compatible with my present 

 limits ; their analogy to the electric phenomena in the clouds, 

 leaves room to suppose they are effected by certain modifica- 



