li' AMERICAN MUSEUM GUIDE LEAFLETS 



Meteoritic masses are almost certainly extremely cold during their 

 existence in outer space, but when they come into the earth's atmosphere 

 friction with the air raises the temperature of the surface to the melting 

 point, producing a great amount of dazzling light as well as superficial 

 heat. In spite of this surface fusion, it is highly probable that the dura- 

 tion of the aerial flight of a meteorite is so short that in many cases the 

 interior does not become even warm.' 



The rapid heating of the exterior and the differences of temperature 

 between different parts of a meteorite often lead to its rupture before 

 it reaches the ground. This is particularly the case with stone meteo- 

 rites, the iron meteorites being tough enough usually to withstand the 

 fracturing agencies. Most of the meteorites which have burst have 

 furnished only two or three fragments, so far as known, but a few have 

 furnished many, while there have been found 700 pieces of Ilessle, 1000 

 pieces of Forest City, several thousand each of Knyahinya and L'Aigle, 

 and about one hundred thousand each of Mocs and Pultusk. The 

 name "stone shower" has been appropriately given to the falls com- 

 prising many individuals. "Iron showers" from bursting siderites are 

 much rarer than the stone showers, only six are known to have occurred, 

 among which Canyon Diablo leads, several thousands of fragments of 

 this famous fall having been found. 



The breaking up of a meteorite is accompanied by an explosion or 

 series of explosions, and often these are startling in their sharpness and 

 intensity, when they occur near the earth. Forest City, 208 pounds of 

 which have been found, just before falling burst in a series of explosions 

 which were heard over an area two hundred miles in diameter. There 

 were three distinct detonations connected with the fall near Butsura, 

 Bengal, which were heard at Goruckpur sixty miles away, although the 

 meteorite was a small one, less than fifty pounds of it having been found. 

 The occurrences at Krakhut, L'Aigle and Fnsisheim have already 

 been mentioned. 



Chemical I 'out position. 



Some forty one elements, four of which are gases, arc said to occur 

 in meteorites, but several of these may be regarded as doubtful. The 



1 See also page 18. 



