PNEUMATICS. 323 



437- Besides these deposites from the atmosphere, 

 which are all of one substance, there are others that 

 cannot he traced to the same origin. These are 

 the Stones which have often heen said, and have 

 of late years been ascertained beyond all doubt, to 

 fall down from the air ; on examination, they are 

 found to be composed in a manner similar to one 

 another, but in many respects unlike to any thing 

 that is found either on the surface or in the bowels 

 of the earth. 



For an account of Meteoric Stones, see HOWARD, 

 Phil. Trans. 1802. IZARN, Lithologlc Atmosplie- 

 rique, Paris, 8 VO , 1803 : and CAVALLO, vol. iv. 

 p. 372., &c. 



In the absence of all analogous appearances, it is per- 

 haps unphilosophical to offer any explanation of 

 the Meteoric Stones. We would only suggest as 

 a mere possibility, that gaseous substances may be 

 thrown up into the air, from the numerous volca- 

 noes on the earth's surface, and may carry with 

 them certain elements of metallic and stony bodies 

 from the mineral regions ; these, while floating 

 about in the atmosphere, may sometimes be col- 

 lected in considerable quantities into one place, 

 where, being subjected to electric or galvanic ac- 

 tion, they are united into a solid mass. The fact, 

 that many of these stones have fallen during thunder 

 storms, seems to limit the place of their formation to 

 the atmosphere of the earth. 



END OF VOLUME FIRST. 



