44 THE POPULAR SCIENCE MONTHLY. 



reason to believe that the series stops just where our power of tracing 

 it ceases ; on the contrary, since the series is continuous as far as it 

 goes, and since our own solar system is constituted as if it belonged 

 to the series prolonged far beyond the limits which telescopic scrutiny 

 has reached, we have reason for believing that such is indeed the in- 

 terpretation of the observed facts. In other words, we may not un- 

 reasonably regard our solar system as a multiple system, a double star 

 at certain ranges of distance, whence only the sun and Jupiter could 

 be seen ; a triple star at distances whence Saturn could be seen ; and 

 a quintuple star where Uranus and Neptune would come into view. 

 To show what excellent reason exists for regarding Mercury, Yenus, 

 the Earth, and Mars, as not to be included in this view, it is only ne- 

 cessary to remark that not one of these planets could be seen until the 

 limits of the solar system had been crossed. To eyesight such as ours, 

 not one of the four terrestrial planets could be seen from Saturn, and 

 still less, of course, from Uranus or Neptune. It would be as unrea- 

 sonable to hold the ring of asteroids, or even the myriads of systems 

 of meteorolites and aerolites, to be bodies resembling the earth and her 

 fellow-terrestrial planets, as it is to hold these terrestrial planets to be 

 bodies resembling Jupiter and his fellow-giants. 



In all characteristics yet recognized by astronomers, Jupiter and 

 Saturn differ most markedly from the earth and her fellow-planets. 

 In bulk and mass they belong manifestly to a different order of cre- 

 ated things ; in density they differ more from the earth than the sun 

 does ; they rotate much more swiftly on their axes ; they receive much 

 less light and heat from the sun ; the lengths of their year exceed the 

 length of the earth's year as remarkably as their day falls short of 

 hers ; the atmospheric envelope of each is divided into variable belts, 

 utterly unlike any thing existing in the earth's atmosphere ; and, last- 

 ly, each is the centre of an important subsidiary scheme of bodies 

 quite unlike the moon (the only secondary planet in the terrestrial 

 family) as respects their relations to the primary around which they 

 travel. 



Notwithstanding all these circumstances in evidence of utter dis- 

 similarity, and the fact that not one circumstance in the condition of 

 the major planets suggests resemblance to the terrestrial planets, as- 

 tronomy continues to treat of the planets of the solar system as though 

 they formed a single family. It would appear as though the teach- 

 ings of the astronomers who lived before the telescope was invented 

 had so strong an inherent vitality, that more than two centuries and 

 a half of discoveries adverse to those teachings are powerless to dis- 

 possess them of their authority. For no other reason can be sug- 

 gested, as it appears to me,, for the complete disregard with which the 

 most striking characteristics of the major planets have been treated 

 by modern astronomers. 



If we consider one feature alone of those which have been just 



