ASTRONOMY AND METEOROLOGY. 367 



it appears that were the moon situated at double her present distance 

 from the earth, her apogee should never deviate more than a few 

 degrees from the sun's place, supposing her eccentricity to remain 

 unaltered. It appears also, that at all greater distances, at which the 

 existence of satellites is possible, the axis of their orbits will have 

 invariably a similar position. 



With the transverse axis of its orbit continually directed to the 

 sun, the satellite will be in a great measure free from the periodical 

 irregularities which at present characterise planetary motions. If it 

 moved in the order of the signs, the slow motion in the aphelion, and 

 the increased length of the radius vector, should cause the action at 

 the svzio-ies to preponderate over that at the quadratures ; and this 

 should produce A PERMANENT DIMINUTION OF THE 

 ECCENTRICITY. Were the motion in an opposite direction, a 

 contrary result may be expected, until the satellite should be com- 

 pelled to desert the earth, or fall to its surface; but it will soon 

 appear that there is scarcely a possibility of a retrograde motion ever 

 attending the process, by which planets must have collected from 

 space, the materials of which their satellites are composed. Should 

 the orbit be elongated in any direction by the disturbing force, the 

 longest diameter will turn to the sun, and thus any considerable devia- 

 tion from a circle will be prevented. 



It is easy to conceive how the masses collected by a planet, and 

 compelled to describe circular orbits around it, might accumulate in 

 numbers and form satellites. When a nucleus once formed, its 

 attraction, extending to a greater distance, should collect the matter 

 very rapidly from the space which it traversed, until after some revo- 

 lutions there should be little left for future acquisitions. Masses too 

 remote to be drawn to this satellite should be disturbed by its attraction, 

 and prevented from acquiring such a conformation of their orbits, or 

 such velocities as may render their coalescence possible. A second 

 satellite could not, therefore, be called into existence until the orbit of 

 the first had been much contracted either from the resistance of a 

 medium, or from the accession of new matter to the primary. Hence, 

 the regular intervals between the moons of Jupiter, Saturn and 

 Herschel. 



But the sun himself is moving through space in a curve, in obedi- 

 ence to the attractions which proceed from myriads of other systems. 

 The masses, therefore, which the sun meets in his course, must have 

 their motions modified and their orbits shaped by the resultant of 

 these forces, and they are sensible to its control long after they 

 become members of our system. Like the sun's action on the 

 secondary planets, this disturbing force must operate with the most 

 efficacy on the bodies near the verge of our system, giving a fixed 

 position to their apsides, and causing them to describe either circles 

 or small curves. If, now, the planets were too remote to produce any 

 sensible irregularities, the formation of a planet from these acquisi- 

 tions of matter should take place near the confines of our system, 

 where motion is slow. But it is only after the numberless ages which 

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