ASTRONOMY AND METEOROLOGY. 329 



proach to uniformity, through space. But the hypothesis of an in- 

 finite increase does not necessarily involve this arrangement, or any 

 of its attendant difficulties. We need only suppose, with Lambert 

 and others, that the mode of formation which we see carried out in 

 those portions of the universe visible to our eyes is continued to in- 

 finity, that out of a proper number of systems of a lower order sys- 

 tems of a higher order are formed, and that the separate systems are 

 always placed at vast distances, compared with the dimensions of the 

 system. The lowest systems in this series are composed of a planet, 

 with one or more satellites, the dimensions of which, astronomically 

 speaking, are inconsiderable. The separate planets are formed into 

 the solar system, being placed at distances of hundreds, or even thou- 

 sands, of millions of miles. The fixed stars, which are supposed to 

 be the centres of solar systems like our own, are placed at distances 

 so great that the entire dimensions of our solar system are but a point 

 in the comparison. There may be great numbers of other starry sys- 

 tems or milky-ways like ours formed into a system, a collection of 

 these systems into another, and so on, without end. Of course we 

 are now in the domain of pure speculation, as all systems of a higher 

 order than those composed of individual stars must remain forever in- 

 visible to mortal eyes, and while man dwells on our planet he has no 

 more means of becoming acquainted with their existence than he has 

 of seeing the inhabitants of Neptune. The subject may therefore be 

 dismissed with the remark, that the arrangement is not, so far as can 

 be seen, carried out with perfect regularity. Other starry systems 

 seem to merge insensibly into clusters, forming part of our milky-way. 



THE INCLINATION OF THE PLANETARY ORBITS. 



In a recent communication to the British Association, by Professor 

 Hennessy, on the above subject, the author stated, that on consulting 

 a synoptic table of the planetary elements, some law had been obtained 

 for the other elements, but none hitherto for the inclinations of the sev- 

 eral orbits. This he conceived arose from the inclinations being set 

 down in reference to the plane of the earth's orbit ; for he found that 

 a very remarkable relation manifested itself when they were tabulated 

 in reference to the plane of the Sun's equator. The author had writ- 

 ten on the board two tables : one, the ordinary table in reference to 

 the ecliptic ; the other, that to which he wished to draw attention, 

 having reference to the plane of the Sun's equator. In the latter, it 

 was seen as a general law that the inclinations of the planetary orbits 

 increased as the distances of the several planets from the sun increased. 

 Thus, the inclination of the orbit of Mercury to the plane of the Sun's 

 equator was but 19' 51", while that of Neptune was 9 6 7 51" ; the 

 only considerable deviation from regular progression being found, as 

 might be expected, among the asteroids : of which, if we take Victo- 

 ria as a type, her inclination is no less than 15 42' 15". The author 

 considered that the fact that the orbits .of the larger planets, Jupiter, 

 Saturn, Uranus and Neptune, are not more inclined, would seem to 

 confirm a surmise of La Place, who, in his Exposition du Systeme du 

 Monde, speculates on the order in which the planets were thrown off 

 from the Sun, and supposes that Jupiter, Saturn, etc., were thus formed 

 long before Mercury, Venus, the Earth and Mars. If so, the oblate- 

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