336 ANNUAL OF SCIENTIFIC DISCOVERY. 



over 60 pounds. It was found in Tazewell county, Tennessee. A large 

 one from Saltillo, Mexico, lay on the table, weighing 2GO pounds. 



Mr. Bartlett (Boundary commissioner) had described to him one speci- 

 men which weighed 600 pounds, and its greatest length was iive feet. 



It was long supposed that these bodies were identified with the shooting 

 stars, but that error is of easy demonstration; for in all the periodically 

 returning occasions of shooting stars, there is not a case on record where 

 the fall of a meteoric stone has accompanied them. Then we can obtain 

 the elevation of the shooting stars, and without difficulty learn their ve- 

 locity. They are often far beyond the circle of our atmosphere, and trav- 

 el at the rate of sixteen miles a second, while we know that nothing can 

 revolve around the earth at a swifter rate than five miles a second. Shoot- 

 ing stars, then, are cosmic bodies, revolving around the sun as a centre. 

 They are self-luminous too. But meteoric stones could not strike the earth 

 in their fall, coming at the rate of sixteen miles a second, without produ- 

 cing very different impressions from what are recorded of their fall. 



They are not of terrestrial origin. The number of those who think that 

 they are is too limited to require a set refutation of that theory. 



They are not of atmospheric origin, aggregated from different directions, 

 hardened like hail, though from different causes. Their form forbids that 

 suspicion. Whence, then, are they ? 



Dr. Smith evidently accepted the " lunar theory." They were masses 

 thrown off with great force from the moon, revolving around that body 

 until in the great eccentricity of their orbits they fall within the circle of 

 our atmosphere ; once within which, and with velocity greatly retarded, 

 our earth becomes their centre. They may have been thrown out from 

 the craters of volcanoes a long time ago, and been thousands of years re- 

 volving before their orbit brought them in contact with our sphere. La- 

 place and Arago, who once held this theory, gave it up ; but they 

 were compelled to do so, or surrender another belief of theirs, that they are 

 identical with shooting stars. One-twentieth of the surface of the moon is 

 volcanic ; and if the craters, as revealed by the telescope, are only in the 

 usual proportion to the height and depth of the volcanoes, there need be 

 no doubt that they have sufficient ejecting force to hurl large masses of 

 volcanic matter to immense distances. Remember, besides, that the attract- 

 ing power of the moon is but one- sixth that of the earth, and that bodies 

 thrown from its surface experience in consequence but one -sixth the re- 

 tarding force they would have when thrown from the earth's surface. 



Look again at the constitution of the meteorite, made up principally 

 of pure iron. It came evidently from some place where there is little or 

 110 oxygen. Now, the moon has no atmosphere, and no water on its sur- 

 face. There is no oxygen there, then. Hurled from the moon, these 

 bodies these masses of almost pure iron would flame in the sun like 

 polished steel, and on reaching our atmosphere would burn in its oxygen 

 until a black oxide coated it ; and this we find to be the case with all our 

 meteorites the black color is only an external covering. 



