AETIOUTES. 118 



cosmicai body not surrounded by an atmosphere, must 

 be in their nature exceedingly arbitrary. The reaction of 

 the interior of such a body against its crust may, indeed, be 

 imagined to be ten times, or even a hundred times, more 

 powerful than that of our present terrestrial volcanoes. The 

 direction of masses discharged from a satellite revolving from 

 west to east, might also appear retrograde, in consequence of 

 the Earth arriving later at the point in her orbit where those 

 masses falL If, however, we duly weigh all the circumstances, 

 which I have thought it necessary to recount lest I should 

 seem to make assertions without having sufficient ground for 

 their support, we shall find the lunar origin ( 69 ) of meteoric 

 stones to be dependent on a number of different conditions 

 whose concurrence would be requisite in order to change the 

 simply possible into the actual. It appears more in analogy 

 with our other views of the formation of the solar system, to 

 admit the separate existence of small planetary masses circu- 

 lating independently in space. 



It is very probable that a large portion of these minute 

 cosmicai bodies may continue their course round the sun 

 undestroyed by the vicinity of our atmosphere, and suffering 

 only an alteration in the eccentricity of their orbits by the 

 attraction of the earth. It is possible, therefore, that they 

 first become visible to us after many revolutions. The sup- 

 posed ascent of shooting stars and balls of fire which Chladni 

 attempted, not very happily, to explain by the reaction 

 of the air strongly compressed in their descent, seems, 

 at first sight, a consequence of some unexplained tangential 

 force tending to throw off the meteors from the earth : but 

 Bessel has asserted, on theoretical grounds, the im- 

 probability of the supposed facts ; and this has been sinc 



