92 Facts from the Arcana of Nature. 



the depth attained from the surface. It is now an ascer- 

 tained fact, that the deep sea is of one invariable tempera- 

 ture, and that a very low one. The calculations of Lenz, 

 based upon Kotzebue's and Beeclry's observations, give 36°, 

 and those of Ross 39° 5 Fahr. The depth at which this 

 temperature is attained is 7,200 feet at the equator, dimin- 

 ishing to 5Q° 26' S. lat., where it attains the surface, and the 

 sea is of equal temperature at all depths. How can we re- 

 concile such facts with the theory of central incandescence of 

 the matter of our globe, or explain them so as to leave a 

 fraction of evidence, in favour of a supposition of the primitive 

 molten fluidity, and present central combustion of the earth ? 

 Yet upon such a gratuitous supposition is the alleged figure 

 of an oblate spheroid educed, as necessarily that of our globe, 

 formerly described as flattened at the poles like an orange, 

 but now regarded by astronomy as so slightly varying from 

 perfect sphericity, as to require in an ordinary model, the 

 nicest calculations or geometrical observation to define the 

 existing difference. The Earth's velocity of rotation upon 

 its axis, aided by the natural law of gravitation of its watery 

 envelope to the centre of gravity, are adequate to account 

 for an almost perfect sphericity of its external aspect, but 

 we have no proof available either of its internal structure 

 and the relative density of its proportions throughout, or of 

 the form of its solid exterior, if divested of its oceanic cover- 

 ing. It may be as " without form," as the unshapely meteor- 

 ites in our museums, and partially or wholly " void" of solid 

 matter internally. How is oxygen supplied to maintain 

 combustion in its central furnace ? And how came water to 

 remain over the vent-holes in the crust of its molten mass ? 



Astronomy declares that " the change, which, owing to pre- 

 cession and nutation, is constantly taking place in the position 

 of the terrestrial axis of rotation, is only in respect of fixed 

 points in space ; for it can be shown that since the earliest 

 recorded astronomical observations, the position of the poles 

 of rotation on the Earth's surface has undergone no altera- 

 tion whatever." Yet it appears that " in consequence of the 

 precession of the equinoxes, the sun's place among the zodi- 

 acal constellations, at any given season of the year, is now 

 greatly different from what it was in remote ages. Sometime 

 before the age of Hipparchus, the first points of Aries and 

 Libra corresponded to the vernal equinoxes, and those of 

 Cancer and Capricorn to the summer and winter solstices. 

 These points have now receded 30° from the constellations to 



