Facts Jrom the Arcana of Nature. 95 



consideration." He, however, first submitted a theory of 

 causation, assuming that the primitive molten fluidity of the 

 Earth's volume was an indisputable fact, and hence there had 

 resulted from its velocity of rotation, an equatorial bulge or 

 redundancy of matter, developing a surface subject to unequal 

 attraction by " universal gravitation " of the sun and moon, 

 the result of which is a reeling motion of the Earth's axis, 

 — stated as only with reference to surrounding space, not 

 admitted as within the periphery of the globe itself, — from 

 east to west, and the recession westward of the equinoctial 

 points. In the time of Hipparchus, this recession amounted to 

 45" annually, but has since varied, and is now stated at about 

 50 J'" annually, equal to one whole degree in seventy years. M. 

 D'Alembert, an ingenious mathematician, attained scientific 

 laurels by his geometrical demonstration of the momenta neces- 

 sarily evoked by the joint attraction of the sun and moon, 

 resulting in the phenomena of precession. Ever since mathe- 

 matical demonstration of perturbations stated to be effected 

 by " universal gravitation," has been resorted to, to explain 

 away noted discrepancies of observations, which, duly investi- 

 gated, might have extended. the area of human knowledge of 

 facts in physical astronomy ; and displaced a host of question- 

 able hypotheses, in favour of an accumulating code of natural 

 laws, the continuous action of which throughout nature, 

 could be vouched for by incontrovertible data, deduced by 

 careful observation in all departments of physical science. 

 Brewster remarks, " The influence of the imagination as an 

 instrument of research, has we think been much overlooked 

 by those who have ventured to give laws to philosophy. 

 This faculty is of the greatest use in physical inquiries. If 

 we use it as a guide, and confide in its indications, it will 

 infallibly deceive us ; but if we employ it as an auxiliary, it 

 will afford us the most invaluable aid." Recent investigations 

 into natural phenomena induce the belief that Newton's solar 

 gravitation theory may be over-strained to account for 

 terrestrial movements ; and that the maximum obliquity of 

 the angle of intersection of the planes of the equator and 

 ecliptic, may have resulted from an unequal development of 

 polar glacial enlargements, effecting perhaps at first a gradual 

 change, but ultimately a sudden alteration of the earth's 

 centre of gravity, when the bulk of the waters enveloping 

 the globe would gravitate into the hemisphere containing the 

 preponderating glacial accumulation, and, by this unequal 

 oceanic distribution, cause the earth to assume her astronomi- 



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