CERTAIN HAllMONIES OF THE SOLAR SYSTEM. 81 



[See in this connexion (69) and its NoteK The seeming perturbations of the 

 atmospheres of Venus and Mercury, and even those of the atmosphere of Jupiter, 

 are also consistent with the supposition of a high temperature.] 



9tli. The very existence of a gaseous or nebulous envelope of the sun, as well 

 as of the atmospheres to so many of the planets, is itself consistent with the hypo- 

 thesis in question. [Confirmed by recent investigations with the spectroscope]. 



lOth. Another evidence of previous high temperature, as the hypothesis would 

 require, is found in the internal heat of the Earth, even now. 



llth. Similar is the evidence of geological facts; many of which require the 

 existence of a very high temperature in ancient times. 



VZth. The evidences of the effects of a former high temperature in the moon, 

 supplement the evidence of geology. 



13^7i. The hypothesis accounts for the lack of an atmosphere to the moon; in 

 the explanation quoted in (69). 



14ith. The hypothesis, in like manner, accounts for the absence of secondary 

 satellites (satellites of satellites) ; and also shows why there are no secondary rings ; 

 in the explanation quoted in (68). 



\5th. The hypothesis accounts for the arrangement by which the moon and (it 

 may be) the other satellites, present the same faces severally to their respective 

 primaries ; the explanation being that quoted in (68). 



16<7t. The hypothesis accounts for the spheroidal form of the planets ; they 

 having been supposed to have been, in older times, in a gaseous or in a liquid 

 state, in which they took a form suited to the rotation of their gravitating material. 

 The researches of Prof. H. Hennesey " have shown that the ultimate ellipticity" 

 in consequence of the accumulation of water, etc., in the equatorial regions, and 

 the gradual abrasion of polar continents in case the Earth were at first a solid 

 sphere, would be ^i^, instead of "that found by actual measurement;"^ viz, a 

 little greater than g-Jg-. The Earth, could not then have been solid at first. The 

 oblateness of Mars seems to be too great ; but it is supposed that the liquid sur- 

 face of some planets was solidified before they could assume the figure appertain- 

 ing to their rotation. 



llth. The molecular constitution and whole composition of aerolites ; so like, 

 and yet in some respects so different from, what we find on the earth, is consistent 

 with a common origin of all from the ancient solar atmosphere. [The spectrum- 

 analysis has, within a recent period, afforded similar testimony, and to a greatly 

 enlarged extent]. 



[The existence of the Zodiacal Light is also consistent with the hypothesis in 

 question. This consistency is not numbered here ; as it must appear in another 

 connexion.] 



' As stated by Prof. Kirkwood- — American Journal of Science and the Arts, for Sept. 1860, 

 p. 16Y. 



11 February, 1875. 



