Dr. Walter Flight — History of Meteorites. 



499 



to illustrate some remarks on the rotation of meteorites. It measures 

 4 ft. 1 in. by 3 ft. 3 in., weighs about 1400 lbs., and is in the form 

 of a ring. When first found, it was set up as an anvil. 



Von Haidinger points out that the greatest extension of the iron 

 is in the plane of the ring, and that the rotation must have taken 

 place in this plane. The question arises : What would be the effect 

 the resistance of the air will exercise on a plate of iron of unequal 

 thickness ? In the centre of the compression, and therefore of the 

 expansion, the air, he finds, would be compressed together in a con- 

 dition resembling that of a solid body. What then will be the effect 

 on a large mass of rock, the uneven surface of which is subjected to 

 the unequal action of a temperature of fusion ? The stone will be 

 bored into, as the Gross-Divina stone has been to a considerable 

 depth ; a similar phenomenon has been remarked in other meteorites. 

 While this will be the effect on brittle stony material, in the present 

 case the resistance of the air, operating on a plate three to four feet in 

 diameter of viscous metal, will be more rapid and energetic. The 

 plate will in process of time be penetrated at one point, and by the 

 gradual expansion of the orifice it will eventually develope into a 

 ring, and arrive in this form on the earth's surface. 



The meteoric iron which was seen to fall at Agram, Croatia (1751, 

 May 26th), has the form of a plate, and bears evidence of having 

 been subjected to the same eroding influence, though in a less degree. 

 Had it been continued to the depth of another inch this iron would 

 have been perforated, as in the case of the Tucson ring. 



The above is a representation, one-twentieth the actual size, 

 of this curious mass, which is preserved in the Smithsonian Institu- 

 tion, at Washington. The figure is reproduced from von Haidinger's 

 memoir. 



