ORIGIN O*' METEOBITES BERWERTH. 317 



these times. Thus the iron of Mazapil is said to have come from the 

 meteoric shower of the 27th of November, 1885, and, according to 

 this, is a fragment of the comet Biela. But this must remain a 

 mere assumption. The time-table of meteorite falls gives proof that 

 the great majority of meteorites have not come to the surface of the 

 earth at the time of swarms of shooting stars. 



In opposition to this briefly outlined theory, according to which 

 the meteorites represent a part of the shooting- star phenomena, an 

 hypothesis was proposed in the seventies in the past century which 

 did not take its origin from astronomical assumptions. It was based 

 on a mineralo-geological basis, upon the study of the component 

 material of the meteorites, and upon the times of arrival of me- 

 teorites of like composition. This new (volcanic) hypothesis, 

 founded upon actual observations, was presented in 1875 by G. 

 Tschermak, of the Viennese Academy of Sciences, and was later 

 through supplemental work augmented and established. If Brew- 

 ster, L. Smith, Haidinger, and Daubree have claimed the origin of 

 meteorites through the dissolution of a heavenly body, so the disin- 

 tegration of small celestial bodies is for the first time ascribed by 

 Tschermak to a volcanic process. From the shape of meteorites 

 it is to be concluded that thej are actual ruins or broken bits which 

 may come from larger planetary masses. Not only th©ir shapes, but 

 also the slicken-sided surfaces occurring in meteorites point to frac- 

 turing in the mass, and many are like volcanic tuffs or clastic masses, 

 as Haidinger and Reichenbach have already suggested. Where 

 Daubree leaves it undecided whether the fragmentation of a world 

 lx)dy is brought about by collision or by explosion, Tschermak based 

 his decision that they resulted from explosive destruction on the 

 physical condition of the meteorites, which are formed by vol- 

 canic explosions unaccompanied by the pouring out of lava just as 

 terrestrial stones which come from explosive craters (similar to the 

 Maaren of Eifel). An explosive activity to which meteorites point 

 can only be brought about by sudden expansions of gases and 

 steam, among which hydrogen may have been in the first rank. 

 Vulcanism as a cosmic phenomena is the destroyer of planetary 

 masses, as we learn from the constituents of meteorites, in harmony 

 with the solar development of stars, which all go through a volcanic 

 phase. The broken bits after their separation are arranged in 

 swarms w^hich cross the orbit of the earth in accordance with law. 

 The most convincing examples for the existence of meteorite streams 

 ai-e formed by the group of eukrites. 



If one ascertains their orbits and the intersection which they make 

 with that of the earth, one finds that this intersection is progressively 

 retarded, which means that the line of nodes relative to the earth 



