164 COSMOS. 



and annual changes of magnetic declination. It has thus been 

 attempted in our own day, with tedious solemnity, to clothe in 

 a scientific garb the quaintly devised fiction of the humorous 

 Holberg.* 



The figure of the Earth and the amount of solidification 

 (density) which it has acquired are intimately connected with 

 the forces by which it is animated, in so far at least as they 

 have been excited or awakened from without, through its 

 planetary position with reference to a luminous central body. 

 Compression, when considered as a consequence of centrifugal 

 force acting on a rotating mass, explains the earlier condition 

 of fluidity of our planet. During the solidification of this 

 fluid, which is commonly conjectured to have been gaseous 

 and primordially heated to a very high temperature, an 

 enormous quantity of latent heat must have been liberated. 

 If the process of solidification began, as Fourier conjectures, 

 by radiation from the cooling surface exposed to the atmo- 

 sphere, the particles near the centre would have continued 

 fluid and hot. As, after long emanation of heat from the 

 centre towards the exterior a stable condition of the tem- 

 perature of the Earth would at length be established, it has 

 been assumed, that with increasing depth the subterranean 

 heat likewise uninterruptedly increases. The heat of the 

 water which flows from deep borings (Artesian wells), direct 

 experiments regarding the temperature of rocks in mines, 

 but above all, the volcanic activity of the Earth shown by the 

 flow of molten masses from open fissures, afford unquestionable 

 evidence of this increase for very considerable depths from the 

 upper strata. According to conclusions based certainly upon 

 mere analogies, this increase is probably much greater towards 

 the centre. 



* [The work referred to, one of the wittiest productions of the learned 

 Norwegian satirist and dramatist, Holberg, was written in Latin, and 

 first appeared under the following title : Nicolai Klimii iter subterra- 

 neum novam telluris theoriam ac historiam quintce monarchice adhuc 

 ndbls incognitcB exhibens e bibliothc.ca b. Abelini. Hafnice et Lipsice 

 sumt. Jac. Preuss, 1741. An admirable Danish translation of this 

 learned but severe satire on the institutions, morals, and manners of the 

 inhabitants of the upper Earth, appeared at Copenhagen in 1789, and 

 was entitled, Niels Klim's underjordisJce reise ved Ludwig Holberg, 

 oversat efter den latinske original af Jens Baggesen. Holberg, who 

 studied for a time at Oxford, was born at Bergen in 1685, and died in, 

 1754 as Hector of the University of Copenhagen.] Tr. 



