VOL. XXIX.] PHILOSOPHICAL TRANSACTIONS. IQf 



works: that having passed over Leghorn, it went off to sea towards Corsica; and 

 lastly, that at Leghorn it was heard to give a very loud report like a great cannon ; 



thrown on such occasions to heights also so much greater. We may easily imagine too such cause of 

 motion to exist in the moon as well as in the earth, and that in a superior degree, if we may judge 

 from the supposed symptoms of volcanoes recently observed in the moon, by the powerful tubes of 

 Dr. Herschel ; and still more, if we consider that all projections from the earth suffer an enormous 

 resistance and diminution, by the dense atmosphere of this planet, while it has been rendered pro- 

 bable, from optical considerations, that the moon has little or no atmosphere at all, to give any such 

 resistance to projectiles. 



Thus then we are fully authorised in concluding, that the case oi possibility is completely made outj 

 that a known power exists in nature, capable of producing the foregoing effect, of detaching a mass 

 of matter from the moon, and transferring it to the earth, in the form of a flaming meteor, or burn- 

 in<^ stone J at the same time we are utterly ignorant of any other process in nature by which the same 

 phenomenon can be produced. Having thus discovered a way in which it is possible to produce those 

 appearances, we shall now endeavour to show, from all the concomitant circumstances, that these 

 accord exceedingly well with the natural effects of the supposed cause, and thence give it a very high 

 degree of probability. 



This important desideratum will perhaps be best attained, by examining the consequences of a sub* 

 stance supposed to be projected by a volcano from the moon, into the sphere of the earth's superior 

 attraction J and then comparing those with the known and visible phaenomena of the blazing meteors 

 or burning stones, that fall through the air on the earth. And if in this comparison a striking coin- 

 cidence or resemblance shall always or mostly be found, it will be difficult for the human mind to 

 resist the persuasion that the assumed cause involves a degree of probability but little short of certainty 

 itself. Now the chief phaenomena attending these blazing meteors, or burning stones, are these : 

 1, That they appear or blaze out suddenly, 2. That they move with a surprising rapid motion, nearly 

 horizontal, but a little inclined downwards, 3 That tliey move in several different directions, with 

 respect to the points of the compass, 4, That in their flight they yield a loud whizzing sound. 

 5. That they commonly burst with a violent explosion and report, 6", That they fall on the earth with 

 great force in a sloping direction. 7. That they are very hot at first, remain hot a considerable time, 

 and exhibit visible tokens of fusion on dieir surface. 8, That the fallen stony masses have all the 

 same external appearance and contexture, as well as internally the same nature and composition. 

 9. That they are totally different from all our terrestrial bodies, both natural and artificial. 



Now these phaenomena will naturally compare with the circumstances of a substance projected by 

 a lurar volcano, and in the order in which they are here enumerated. And first with respect to the 

 leading circumstance, that of a sudden blazing meteoric appearance, which is not that of a small 

 brieht spark, first seen at immense distance, and then gradually increasing with the diminution of its 

 distance. And this circumstance appears very naturally to result from the assumed cause. For, the 

 body being projected from a lunar volcano, may well be supposed in an ignited state, like inflamed 

 matter thrown up by our terrestrial volcanoes, which passing through the comparatively vacuum, in 

 the space between the moon and the earth's sensible atmosphere, it will probably enter the superior 

 parts of this atmosphere with but little diminution of its original heatj from which circumstance, 

 united with that of its violent motion, this being 10 or 12 times that of a cannon ball, and through 

 a part of the atmosphere probably consisting chiefly of the inflammable gas, rising from the earth to 

 the top of the atmosphere, the body may well be supposed to become suddenly inflamed, as the 

 natural effect of these circumstances 3 indeed it would be surprising if it did not. From whence it 



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