VOL. XXIX.] PHILOSOPHICAL TRANSACTIONS. 10^ 



He concludes, from the apparent velocity it went with at Bononla, at above 

 50 miles distance, that it could not be less swift, than l6o miles in a minute of 

 time, which is above 10 times as swift as the diurnal rotation of the earth under 

 the equinoctial, and nut many times less than that with which the annual mo- 

 tion of the earth about the sun is performed. To this he adds its magnitude, 

 which appeared at Bononia larger than the moon in one diameter, and above 

 half as large again in the other ; which with the given distance of the eye, 

 makes its real less diameter above half a mile, and the other in proportion. 

 This supposed, it cannot be wondered that so great a body moving with such an 

 amazing velocity through the air, though so much rarefied as it is in its upper 

 regions, should occasion so loud a hissing noise, as to be heard at such a dis 

 tance as it seems this was. But it will be much harder to conceive, how such 

 an impetus could be impressed on this body, which far exceeds that of any 



must be that of a body so much larger, which is of an irregular form and surface too, and striking 

 the air with 50 or 100 times the velocity. 



5. That they commonly burst and fly in pieces in their rapid flight, is a circumstance exceed- 

 ing likely to happen, both from the violent state of fusion on their surface, and from the extreme 

 rapidity of their motion tlirough the air. If a grinding stone, from its quick rotation, be sometimes 

 burst and fly in pieces 5 and if the same thing happens to cannon balls, when made of stone, and 

 discharged with considerable velocity, merely by the friction and resistance of the air; how much 

 more is the same to be expected to happen to the atmospheric stones, moving with more than 

 50 times the velocity, and when their surface may well be supposed to be partly loosened or dissolved 

 by the extremity of the heat there. 



6. That the stones strike the ground with a great force, and penetrate to a considerable depth, as 

 is usually observed, is a circumstance only to be expected, from tlie extreme rapidity of their 

 motion, and their great weight, when we consider that a cannon ball, or a mortar shell, will often 

 bury itself many inches, or even some feet in the earth. 



7. That these stones, when soon sought after and found, are hot, and exhibit the marks of recent 

 fusion, are also the natural consequences of the extreme degree of inflammation in which their 

 surface had been put during tlieir flight through the air. 



8. That these stony masses have all the same external appearance and contexture, as well as in- 

 ternally the same nature and composition, are circumstances that strongly point out an identity of 

 origin, whatever may be the cause to which they owe so generally uniform a conformation. And 

 when it is considered, P^^hly^ that in those respects they diiFer totally from all terrestrial compositions 

 hitherto known or discovered, they lead the mind strongly to ascribe them to some other origin 

 tlian the earth we inhabit j and none so likely as coming from our neighbouring planet. 



Upon the whole then it appears highly probable, that the flaming meteors, and the burning stones 

 that fall on the earth, are one and the same thing. It also appears impossible, or in the extremest 

 degree improbable, to ascribe these, either to a formation in the superior parts of the atmosphere, 

 or to the irruptions of terrestrial volcanoes, or to the generation by lightning striking the earth. 

 But on the other hand, that it is possible for such masses to be projected from the moon so as to 

 reach the eartli : and tliat all the phaenomena of these meteors or falling stones, having a surprizing 

 conformity with the circumstances of masses that may be expelled from the moon by natural causes, 

 unite ui forming a body of strong evidence, that this is in all probability and actually the case. 



