ORIGIN OF METEORITES — BERWERTH. 319 



outer planets of the solar system to 1.4 in the planet Jupiter and 1.1 

 even in Neptune — 



Density. 

 Earth 5.6 



Moon 3.4 



Jupiter 1.4 



Neptune 1.1 



the supposition becomes the greatest probability that in space parti- 

 cles are spread abroad in clouds of loose consistency, which consist 

 of matter like rock dust, salt-like compounds, carbon, and hydro- 

 carbons, which come into the solar system in streams and upon their 

 entrance are consumed, leaving behind carbonic acid, vapor, and fine 

 dust. 



The Tschermak hypothesis mentioned here gains in importance 

 when we consider the opinions of many astronomers of to-day, ac- 

 cording to which the completion of the heavenly bodies is incon- 

 ceivable without vulcanism. One need but observe the conditions 

 upon our earth, the moon, and the sun. Also, we find on the comets 

 with elliptic courses phenomena which may be connected or com- 

 pared with volcanic occurrences. Hertz considers the comet tails to 

 be electric waves, Goldstein considers them kathode tufts, others 

 consider them alpha rays of helium, and Svante Arrhenius declares 

 them of mechanical origin, formed through pressure of light radia- 

 tion. He considers the particles of the comets so tiny that they no 

 longer obey the law of gravitation, but are forced out into space by 

 the light rays of the sun, and by electric discharges in the heads of 

 the comets, which also work repulsively upon the material forming 

 the tail. All these phenomena are straightway compared with the 

 great stresses in the interior of the planets, as with volcanic forces, 

 which also Tschermak has applied to the explosive fragmentation of 

 small world bodies and by this means has explained the origin of 

 meteorites. 



Paying due respect to the opinion of Daubree on the relationship 

 of meteorites to planets and to Tschermak's derivation of meteorites 

 from small planetary bodies, E. Suess reminds us of the variability 

 in the light of the planetoids as observed by Seeliger and TVolf. 

 Since the course of the latter lies partly outside and partly inside 

 that of Mars, his view is corroborated that between Mars and Jupiter 

 there has existed a unified planetary mass which, according to our 

 knowledge of the constftuents of meteorites, must have come from 

 the basic rocks occurring in the kernel of the earth. We therefore 

 find here Tschermak's conception applied to the dissolution of a 

 definite planet which Olbers missed 100 years ago and in the place 

 of which the planetoids were discovered. Suess says : " Meteorites 

 and planetoids are nothing else than the passing witnesses of an epi- 

 sode which has taken place in the history of our planetary system." 



