METEORITES — HENDERSON AND PEBRY 241 



graphic instruments in England recorded pressure waves. An engi- 

 neer on the Trans-Siberian railway had to stop his train the night 

 of the fall to prevent its being derailed by earth waves — and this was 

 more than 400 miles from the place where the meteorite hit. Fortu- 

 nately the region of the fall was ver}' sparsely inhabited, and for 

 that reason it was a long time before the world knew what happened 

 that night. When the scene was reached by outsiders, it was found 

 that all the trees within a radius of 60 miles of the center of impact 

 were blown flat. They were not strewn over the ground in a confused 

 manner, but were arranged radially from the center of impact. For 

 much of the distance that the trees were blown over, the wood was 

 charred by the heat waves. It is doubtful whether any man or animal 

 could have survived within many miles of the spot where the mass 

 hit. It would be difficult to pick a spot on the globe where such an 

 event would involve less danger to man. However, it would have 

 been a different story had this meteorite arrived on earth 4 hours and 

 47 minutes later, because it would then have made a perfect hit on a 

 large city — Leningrad. 



Canyon Diablo crater in Arizona is the largest of these meteoritic 

 holes, and from the area surrounding its rim several tons of iron 

 meteorites have been collected. None of the individual specimens thus 

 far located is very large, the maximum weight being about 1,000 

 pounds, but some of these large specimens have been found several 

 miles from the crater rim. No meteoritic material has as yet been 

 found around the Siberian fall, but collecting in that area is most dif- 

 ficult. The quantity of meteoritic material buried at either place is 

 problematical, and also the size and weight of the mass that struck the 

 earth. It is certain, however, that a most violent explosion resulted 

 when such a vast quantity of energy was abruptly checked and turned 

 into heat and wave energy. 



. . TYPES OF IRON METEORITES 



A few years ago the National Museum received several irons from 

 northern portions of Giile where towns and named geographic land- 

 marks are not abundant. The reported localities were given in miles 

 from railroad stations or mining camps. When these irons were sec- 

 tioned all were found to have similar structures belonging to the 

 hexahedrite group. It was then hoped that chemical investigations 

 would establish certain differences, but as the work progressed and the 

 results were tabulated, it was found that they were all practically iden- 

 tical. The distribution of these nine Chilean meteorites is confined 

 to a narrow strip extending 8° 54' of latitude north and south and 

 1°56' of longitude east and west. It is hardly logical to consider all 

 of them as being a part of the same fall, and yet it is equally difficult 



