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hypothesis, instead of losing ground, has, on naore mature consideration, greatly enforced
itself, in consequence of a series of reflexions deliberately made on that subject,
as well as from having read some hints thrown out by monsieur de la Métherie, in his
Journal de Physique, which, in a great measure, correspond with my own,—this eminent
naturalist having been obliged to philosophise in a similar way on the causes which
have produced the singular and surprising appearances observable on our globe.
This hypothesis, I readily acknowledge, is open to objections; as, in the first
place, the action of the planets on the nodes of the earth's orbit might possibly be
alleged ; secondly, that this diminution of the angle formed by the ecliptic and equator,
at present known to exist, may be caused by the sole action of the planets on the
annual revolution of the earth, which forces it insensibly to change the direction of its
orbit. Such, indeed, might be the objections, which are doubtless admissible, and
which, on a future day, I purpose elucidating more at large ; yet. In fact, do they only
serve to prove the impossibility of a perfect parallelism of the poles—a circumstance by
no means necessary to produce all the effects which a too great or near approach of the
poles would naturally occasion on the globe, particularly if it be considered {supposing
the formation of the primitive mountains by crystallisation) that the sea need not have
risen towards the equator higher than about nineteen thousand four hundred feet,
which, though the elevation of the highest peaks of the Andes, is scarce more than the
two thousand one hundred and sixty-sixth part of the diameter of the earth at the
equator.
But, without entering at present into a more minute detail on this subject, I shall
pass on to the different facts and data which I consider as the basis of my supposition ;
viz. First, that the diameter of the earth, under the equator, being found, by the several
mensurations, to be seven millions nine hundred and forty thousand five hundred and
ninety-iight English miles, and the poles, seven millions nine hundred and three thousand
six hundred and fifty, it of course appears that the earth's equatorial diameter
is to that of the poles as 215 to 214, or, in other words, that the former surpasses or
exceeds the latter by 36TVA miles,—so that there remains no manner of doubt but that
the figure of the earth is now fully determined to be an oblate spheroid. Secondly, that
since this figure of the earth perfectly co-incides with the laws of gravity, fluidity, and
centrifugal force, heretofore explained by Newton, there can therefore exist no doubt
that the surface of our globe was onCe entirely covered by the sea. Thirdly, that as
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at present nearly one half of tliis same surface of the globe is discovered, which we consider
as forming our continents and islands, the sea can only have receded by the
following causes : 1st, by evaporation, which must, at that period, have been very considerable
; 2dly, by a precipitate retreat into the interior of the globe, by the outer crust
of large caverns falling in, or by the sea finding its way into the cavitics of the earth ;
3dly, by a kind of transmutation from the poles to the equator, or, finally, by the power
of the three acting together at one and the same time. Fourthly, that there was doubtless
a time when the centrifugal force was infinitely more considerable than at present,
and, according to the three unalterable laws of nature, viz. gravity, fluidity, and centrifugal
force, above established, the latter must have forced the waters which covered
the poles to recede, or throw themselves towards the equator ; so that the sea, having
thus risen to an extreme height near that circlc, enlarged the equatorial diameter of the
earth, and rendered its figure more spheroidical,—and, in all probability, at that period
was formed the high chain of mountains situate between the equator and the fortyfifth
degree of latitude, both on its northern and southern sides, which elevation gradually
diminishes as they recede from the equator. Fifthly, that the cause of this
receding of the waters from the poles towards the equator can have been no other
than an extreme approachment of the poles of the equator and the ecliptic, which
must nearly have co-incided ; for the action of the sun being then pretty constantly
direct between the tropics, its attraction must necessarily, in some measure, have greatly
diminished that of the earth, and consequently increased the centrifugal force of the
fluid by which it was then covered. This supposition appears greatly strengthened by
the extreme tides even now felt at all times between those circles, though more particularly
during the equinoxes, and when the moon is In conjunction or opposition with
the sun ; as also by the gradual diminution of those same tides, in proportion as they
draw nearer the poles, where they almost disappear. Sixthly, that all appearances at
present prove that approachment of the poles of the equator to those of the ecliptic,
or, which is the same thing, to those of the tropics, if we compare the observations made
upwards of two thousand years ago with thôse of the present sera; for the learned
Greek astronomer Pythias, as well as llipparchus, who lived two hundred and fifty
years before Christ, found^the Inclination of the ecliptic to the equator to be at that
time 23" 51'20" ; and Ptolemy, who lived in the fourth century, 23® 50' 22"; whereas
the chevalier Louville, at the commencement of the present century, having gone to