THE COMPOSITION AND STRUCTURE OF METEORITES 

 COMPARED WITH THAT OF TERRESTRIAL ROCKS. 1 



By George P. Mebeill, 

 Head Curator of Geology, U. 8. National Museum. 



(With 9 plates.) 



The name " meteorite " is applied to masses of stone and iron 

 which occasionally find their way to the earth from space. They are 

 the tangible evidences of the identity of matter in the meteor or 

 shooting star with that of our sphere. Their fall, if such it can 

 properly be called, is accompanied by a rush and roar like that 

 attendant upon the swift flight of any solid body through the atmos- 

 phere. Almost invariably, also, there is an explosion or series of 

 explosions giving rise to sounds comparable to the firing of musketry 

 or heavy cannonading. Falls occurring after sundown are usually 

 accompanied by a trail of light 

 which is due to combustion caused 

 by the pressure of the atmosphere. 

 Few accurate illustrations of falls 

 are available, since the brief time 

 occupied by the phenomenon gives 

 little opportunity for photograph 

 or sketch and too much is left to 

 the imagination to make them of fig. i.— stone meteorite, bath fdr- 

 value. Those here given (pi. 1) 



are of falls which took place near Quenggouk in India in 1857 

 and in Knyahinya in 1866. The meteorite as found, if a stone, pre- 

 sents almost invariably a thin, glassy, dark colored crust, which is due 

 to the fusion of the meteorite on its outer surface and the rapid cool- 

 ing which ensues on its reaching the ground. In many instances, it is 

 beautifully fluted by this stripping off of the fused material in its 

 flight through the atmosphere, as shown in the stone which fell near 

 Bath Furnace, Kentucky, 1903 (fig. 1). 



Although it is estimated that thousands and even millions of these 

 bodies come into our atmosphere every day, but few of them reach 



1 Adapted from a lecture delivered before the Geological Society of Washington. 



175 



