HOVEY, THE FOYER METEORITES 11 



2. "Siderolites," or iron-stone meteorites, which are formed of a 



nickel-iron sponge, or mesh, containing stony matter in the 

 interstices; 



3. "Aerolites," or stone meteorites, which are made up mainly of 



stony matter, but almost always contain grains of nickel-iron 

 scattered through their mass. 

 The line of demarcation between these classes is not always sharp, and 

 there are many subordinate kinds of aerolites. 



Countless numbers of meteoritic bodies, mostly of minute size, 

 must exist within the boundaries of the solar system, since from fifteen 

 to twenty millions of them enter the earth's atmosphere every day. 

 Almost all of these are dissipated in our atmosphere through heat 

 produced by friction with the air, so that the only evidence of their 

 presence is a trail of light across the sky. This usually is visible only 

 at night, and is familiar to all as a shooting star or meteor. Shooting 

 stars are to be seen almost every evening, but they are particularly 

 abundant during August and November. Sometimes the November 

 shower of meteors has been so pronounced that the sky has seemed 

 fairly to radiate lines of fire, an effect far surpassing in brilliance the 

 most ambitious artificial fire works. Not one in a hundred million of 

 these shooting stars, however, reaches the earth in a recognizable mass; 

 in fact, there are records of only about 685 known meteorites which are 

 represented in museums and private cabinets. 



The weight of known meteorites varies between wide limits. The 

 lightest independent mass is a stone meteorite weighing about one sixth 

 of an ounce called Muhlau from the town in the vicinity of Innsbruck, 

 Austria, near which it was found in 1N77; the heaviest mass known is 

 Ahniohito, of the Fover collection, an iron meteorite weighing more 

 than thirty-six and one half tons which came from Cape York, Green- 

 land. Some showers of meteorites have furnished even smaller in- 

 dividuals than Miihlau. Forest City, well represented in the Foyer 

 collection, has been found in fragments weighing one twentieth of an 

 ounce. Pultusk is a famous fall and the smallest of the " Pultusk peas," 

 as the material is called, weigh less than one thirtieth of an ounce each, 

 while Hessle fell in a veritable rain of meteoritic dust, the smallest parti- 

 cles of which weigh about one four hundred twenty-fifth of an ounce and 

 could never have been found had they not fallen on an ice-covered lake, 

 where they were readily seen and recognized. 



