i SS French National hijl'tiaie. 



Chemilts at prefent would be much embarraffed to find in 

 the atmofphere the component principles which have been 

 difcovercd bv analyfis in the (tones given to them as having 

 tallen from the clouds; and on this account they would na- 

 turally reject fuch events as abfurd. But C. Laplace has 

 mentioned an explanation, which he announces not as the 

 only one which could be given of them, and not to prove 

 their exiftence, but to fliow that we ought not to rejeiSl them 

 as abfurd, and to fufpcnd our opinion until time has procured 

 ibme further illuftration. 



It is fhown, by a very fimple calculation, that a body pro- 

 lefted from the moon \vo\ild require only a velocity nearly 

 quintuple that o( the bullet of a 24-pounder difcharged with 

 a quantity of gunpowder equal to half its weight, to proceed 

 to a diftance from that fatellite where the intenfity of its 

 attraftion would be the fame as that of the earth. The 

 bodv, when it had paflTed this point, being in the fphcre of the 

 aiStivityof our globe, would neceflarily fall to itsfurface. The 

 appearance of very confiderable volcanoes obferved on the 

 furface of the moon does not render fuch a conjecture impro- 

 bable; but, independentiv of eruptions, which may be more 

 or kfs uncommon, it will not often happen that the direftion 

 of the projection will be that which the combined motions 

 of the earth and moon require in order that a projeAile 

 thrown from the latter body may meet with the former. 



The atmofphere of the moon, which is doubted by many 

 aftronomers, is fo rare and of lb little extent that it could op- 

 pofe only a verv feeble refinance to ihofe bodies wliich might 

 move in it. The cafe is not the lame with the lerrefirial at- 

 mofphere : it reduces alnioft to a tenth of iis extent the largeft 

 range of a piece of ordnance; and the refiftance it oppofes to 

 rapid motion is fiich, that to make a body projected from 

 Vefuvius reach France, it would be necelfary that it fhould 

 have a projection far greater than that w hich would carry a 

 lunar body to the limits of the fphere of the a6livlty of that 

 fatellite. 



ft is therefore not poffible to fuppofe that flones found at 

 a dillance from terreftrial volcanoes are -the product of the 

 eruptions of thefe mountains : and mineralogy alfo oppofes 

 this explanation; for none of the volcanic productions known 

 are analogous to thofe fuppofed to have fallen from the 

 clouds. 



HExr- 



