5G cosmos. 



us to the distribution in space of cosmical bodies — the periods 

 of variable stars — and the slow revolution of double stars. 

 That which, from its very nature, is not amenable to meas- 

 urement, such as the relative position and configuration of 

 starry strata or rings of stars, the arrangement of the uni- 

 verse, and the effects of powerfully metamorphic physical 

 forces^ in the sudden appearance or extinction of the so-called 

 new stars, excite the mind the more deeply and vividly, its 

 touching on the confines of the graceful domain of fancy. 



We purposely abstain in the following pages from entering 

 on the consideration of the connection existing between our 

 solar system and the systems of other fixed stars, nor shall we 

 revert to the question of that subordination and annexation 

 of cosmical systems which might almost be said to force it- 

 self on our notice from intellectual necessity ; nor yet will 

 we consider whether our central body, the Sun, may not it- 

 self stand in some planetary dependence on a higher system 

 — not even, perhaps, as a main planet, but merely as a plan- 

 etary satellite, like Jupiter's moons. Limited within the 

 more familiar sphere of our solar region, we, however, enjoy 

 this advantage, that with the exception of what refers to the 

 signification of the surface- appearance or gaseous envelopes 

 of the revolving cosmical bodies, the simple or divided tails 

 of comets, the ring of the zodiacal light, or the mysterious ap- 

 pearance of meteoric asteroids, almost all the results of ob- 

 servation admit of being referred to numerical relations, as 

 the deductions of strictly-tested presuppositions. It does not, 

 however, belong to the sketch of a physical description of the 

 universe to test the accuracy of such presuppositions, its prov- 

 ince being simply to give a methodical arrangement of numer- 

 ical results. They constitute the important heritage which, 

 ever augmenting, is bequeathed by one century to another. 

 A table, comprising the numerical elements of the planets - 

 (that is to say, their mean distances from the Sun, sidereal 

 periods of revolution, the eccentricity of their orbits, their in- 

 clination toward the ecliptic, their diameter, mass, and dens- 

 ity), would now embrace within very narrow limits the rec- 

 ord of the great intellectual conquests of the present age. Let 

 us for a moment transport ourselves in imagination to the 

 times of the ancients, and fancy Philolaus the Pythagorean, 

 the instructor of Plato, Aristarchus of Samos, or Hipparchus, 

 in possession of such a numerical table, or of a graphic rep- 



* On the appearance of new stars, and their subsequent disappear- 

 ance, see p. 151-164. 



