FIGURE OF THE EARTH. 163 



aspect of nature in my journeyings by sea and land, by the 

 careful study of forms and forces, and by a vivid impression 

 of the unity of nature in the midst of the most varied portions 

 of the Earth. In the rapid advance of all branches of physical 

 science, much that is deficient in this attempt will, perhaps, 

 at no remote period, be corrected, and rendered more perfect, 

 for it belongs to the history of the development of knowledge 

 that portions which have long stood isolated become gradually 

 connected, and subject to higher laws. I only indicate the 

 empirical path, in which I and many others of similar pursuits 

 with myself are advancing, full of expectation that, as Plato 

 tells us Socrates once desired, " Nature may be interpreted by 

 reason alone."* 



The delineation of the principal characteristics of telluric 

 phenomena must begin with the form of our planet and its 

 relations in space. Here, too, we may say that it is not only 

 the mineralogical character of rocks, whether they are crys- 

 talline, granular, or densely fossiliferous, but the geometrical 

 form of the Earth itself, which indicates the mode of its origin, 

 and is, in fact, its history. An elliptical spheroid of revolu- 

 tion gives evidence of having once been a soft or fluid mass. 

 Thus the Earth's compression constitutes one of the most an- 

 cient geognostic events, as every attentive reader of the book 

 of nature can easily discern ; and an analogous fact is pre- 

 sented in the case of the Moon, the perpetual direction of whose 

 axes toward the Earth, that is to say, the increased accumula- 

 tion of matter on that half of the Moon which is turned to- 

 ward us, determines the relations of the periods of rotation and 

 revolution, and is probably cotemporaneous with the earliest 

 epoch in the formative history of this satellite. The mathe- 

 matical figure of the Earth is that which it would have were 

 its surface covered entirely by water in a state of rest ; and it 

 is this assumed form to which all geodesical measurements of 

 degrees refer. This mathematical surface is difierent from 

 that true physical surface which is affected by all the acci- 

 dents and inequalities of the solid parts. f The whole figure 

 of. the Earth is determined when we know the amount of the 



* Plato, Ph(tdo, p. 97. (Arist., Metaph., p. 985!) Compare Hegel, 

 Philosophie der Geschichte, 1840, s. IG. 



t Bessel, Allgemeine Betrachtungen uher Oradmessungen nach astro- 

 nomisch-geoddtischen Arbeiten, at the conclusion of Bessel and Baeyer, 

 Gradmessung in Ostpreussen, s. 427. Regarding the accumulation ol' 

 matter on the side of the Moon turned toward us (a subject noticed 

 in an earlier part 'jf the text), see Laplace, Expos, dii Syst. du Monde, 

 p. 308. 



