considered Geographically, Statisticaliy, and Cosmically, 337 



ture and so much confusion respecting the nature, origin and 

 phsenomena of these bodies, any ray of light is acceptable to the 

 theorist, and anything like fact or tabulated statistics, of value. 

 In continuation, then_, and in search of further evidence, this 

 part of our subject may also be incidentally considered in another 

 way. 



The average specific gravity of about seventy stones* I find 

 to be 3*4, the highest being about 3-95 and the lov/est \'7 ; but 

 as those possessing the smallest specific gravity are necessarily 

 the most destructible and fragile, and after meteoric explosion 

 less likely to arrive on the surface of the earth in an entire or 

 tangible state, we may very fairly take their average density 

 nearer the mean of these two extremes^ say 3*0. 



We may now construct a table of densities (taking water as 1), 

 which is not without interest, as perhaps bearing on the subject 

 in hand. 



The specific gravity of Mercury is about . . 15*7 



Venus ... . . 5*9 



Earth ... . . 5*7 



1 ... Mars ... . . 5-3 



Aerolites (3*9 to 1*7, say) 3*0 

 Asteroids . . (?) 



Jupiter ... . . 1*4 



This then looks like additional confirmation of the theory of 

 what are called meteorites, or aerolites, belonging to the series 

 of planets, and having their orbits at a greater mean distance 

 than that of the eartVs from the sun. Bearing this in mind, as 

 also the probability of the fact of our meeting with more of them 

 on the side of the summer solstice, or when the earth is at her 

 aphelion J I would draw attention to the following extract from a 

 paper in the American Journal of Science for July 1854, entitled 

 " Considerations on the group of small Planets situated between 

 Mars and Jupiter," by M. U. J. Le Verrier; the paper in ques- 

 tion being a translation and abbreviation of the original in the 

 Comptes Rendus, vol. xxxvii. p. 793 : — 



" If the perihelia of the asteroids, known and unknown, were 

 distributed uniformly in all parts of the zodiac, the second term 

 of the motion of the perihelion of Mars or of the earth might be 

 neglected ; because the action of those masses, whose perihelia 

 are situated in one-half of the heavens, would be destroyed in this 

 second term by the action of those masses whose perihelia are 

 in the other half. But we have seen that there is great liability 

 to error in reckoning upon such a uniformity in their distribu- 

 tion ; the perihelia of twenty out of twenty-six being placed in 



* Iron falls are comparatively very rare, as compared with stone falls; 

 the usual specific gravity of meteoric stones is about 3*5. ■*" »^ ''-s^* -' 



