THE ASTEROIDS BETWEEN MARS AND JUPITER. 



By Daniel Kirkwood, LL. D., 

 Professor of Mathematics in the University of Indiana. 



PREFACE. 



The discovery of the minor planets between Mars and Jupiter has 

 opened to astronomers of the nineteenth century a. new and highly in- 

 teresting department of research. The wide diffusion of these planetary 

 masses ; the interlacing and approximate intersection of their orbits ; 

 the peculiar relations between some of their periods and that of Jupiter, 

 the great disturbing force immediately exterior; and, finally, the bear- 

 ing of these recently-discovered facts on the cosmogony of our system, 

 all suggest important problems whose solution may require years of 

 observation and research. 



The views presented in the following paper have been briefly stated at 

 different times* and sustained by such facts as were available at the 

 time of publication. So rapid, however, has been the recent progress 

 of discovery, and so remarkable the accordance of accumulated facts 

 with the theory announced when but half the asteroids now known 

 had been observed, that a revision of the whole subject, including the 

 latest discoveries, has been deemed desirable. The tabular elements 

 adopted are taken from the Berliner Astronomisches Jahrbuch for 1877, 

 except where more recent results have been obtained from the Astronom- 

 ische Nachrichten. 



THE ASTEROIDS. 



1. It is proposed (1) to arrange the planets between Mars and Jupiter 

 in the order of their discovery; (2) to tabulate their elements in the 

 form most convenient for purposes of comparison ; and then, (3) by a 

 discussion of these elements in their mutual relations, as well as in 

 their relations to Jupiter, the planet by which their motions are chiefly 

 disturbed, to exhibit the evidence they afford in regard to the formation 

 and development of the planetary system. 



* Proc. of the A. A. A. S. for 1866 ; Meteoric Astronomy, cbap. xiii ; Monthly Notices 

 of the R. A. H., vol. xxix ; and Proc. of the A. A. A. S., for 1875. 



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