HOVEY, THE FOYER METEORITES 11 
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‘“‘Siderolites,” or iron-stone meteorites, which are formed of a 
nickel-iron sponge, or mesh, containing stony matter in the 
interstices; 
3. “‘Aérolites,” 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 aérolites. 
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 Miihlau from the town in the vicinity of Innsbruck, 
Austria, near which it was found in 1877; the heaviest mass known is 
Ahnighito, of the Foyer 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. 
