314 ANNUAL EEPOET SMITHSONIAN INSTITUTION, 1916. 



(Weltworlken), comets and meteorites are distinguished from one 

 another only through their relative size. The formations occurring 

 at the boundary of our atmosphere as loose, dust-like, or gaseous 

 aggregates lose their cosmic velocity through its resistance, and 

 finally, by the explosions taking place, are compacted into a solid 

 body. 



Chladni, however, did not consider it impossible that the meteor- 

 ites might be remnants of a destroyed world body, as an illustration 

 of which he mentioned the disappearance of a planet between Jupiter 

 and Mars. Olbers gave occasion for this discover}^ In portraying 

 the solar system the space between Mars and Jupiter caused him 

 great vexation, and he anticipated that a planet might be found 

 there. This ingenious idea was soon afterwards verified by the dis- 

 covery of the asteroids Ceres, Pallas, Juno, and Vesta, which he 

 now conceived to be broken pieces of the great planet missed by him. 

 The little planets (asteroids), denoted here as fragments, belong to 

 the ring now laiown as planetoids, * * * which a hundred 

 years ago were reported to be angular, not always of uniform size, 

 and therefore of irregular form and variable light intensity. We 

 shall see further on that very recently E. Suess has claimed the 

 vanished planet and the planetoids which were derived from it as 

 the sources of our meteorites. 



There were many respected adherents of the hypothesis of the 

 origin of meteorites from the volcanoes of the moon. Telescopic 

 observation had at this time already given information as to the sur- 

 face of the moon, " upon which there were overlapping mountains, 

 large chains of mountains extending for great distances, depressions, 

 craters, and planes," so v. Ende writes in his book "Ueber Massen 

 und Steine die aus dem Monde auf die Erde herabgefallen sind," 

 1904. V. Ende endeavors to strengthen Chladni's hypothesis and to 

 establish, or at least make probable, the connection between the earth 

 and its satellites. Olbers first expressed the moonstone hypothesis 

 on the occasion of the fall of a meteorite at Siena in 1795. 



The great geometrician Laplace expressed the same supposition, 

 which Blumenbach also took up with much approval and called it 

 "the most plausible opinion concerning these things." Arago and 

 Smith were also of the same opinion, and Berzelius, too, was an 

 active follower of the lunar hypothesis in 1836. According to his 

 opinion the meteoric stones came from two different volcanoes on the 

 moon. * * * But when it was established that a volcano on the 

 moon would not possess sufficient energy to impart to an ejected 

 block of stone the necessary initial velocity to reach our earth the 

 hypothesis of the lunar origin fell into disfavor. Strange to relate, 

 it has, however, even at the present day, some individual upholders — 

 for example, the Dutchman Verbeeck, who considers that the glasses 



