Ridpath's history of the world; being an account of the ethnic origin, primitive estate, early migrations, social conditions and present promise of the principal families of men .. . ING.—ASTRONOMICAL ARGUMENT. 61 the common nebulous mass, began to beevolved into worldhood, and which willVibrations of the continue to the end ofSS*£u!£ our planetary career. Webution of heat, must here refer to manyastronomical facts which are familiar asfacts, but of which the significance hasin some measure been overlooked. Theorbit of the earth is an ellipse, havingthe Sun in one of the foci; but the ele-ment
Ridpath's history of the world; being an account of the ethnic origin, primitive estate, early migrations, social conditions and present promise of the principal families of men .. . ING.—ASTRONOMICAL ARGUMENT. 61 the common nebulous mass, began to beevolved into worldhood, and which willVibrations of the continue to the end ofSS*£u!£ our planetary career. Webution of heat, must here refer to manyastronomical facts which are familiar asfacts, but of which the significance hasin some measure been overlooked. Theorbit of the earth is an ellipse, havingthe Sun in one of the foci; but the ele-ments of the ellipse are not the contrary, the two axes of ourorbit lying at right angles to each other approached, but never quite elongation of the minor axis, withthe consequent expansion of the orbit,ceases, and the major axis once morebegins to project like a lengthening arrowinto space. These changes in the two axes of theorbit, with the consequent fluctuationtoward and away from the circle, con-tinue at immense intervals, and willcontinue as long as the present systemof world order endures. Under the forceof the precession of the equinoxes, the. SATURN-A RING PLANET. are inconstant or variable quantities. Achange is ever going on by wThich theratio between the major axis and theminor axis is affected. The character of the earths orbit isthereby constantly modified. At first itapproximates the circle, and then recedesfrom the circle until itreaches a maximum elonga-tion. This elongation, ordeparture from the circle, is called theeccentricity of the orbit. Having reachedthe maximum of this eccentricity, themajor axis begins to contract and theorbit to expand laterally, until after agreat lapse of time the circle is again Nature of thefluctuation inour orbital axes position of the two axes, always at rightangles to each other, constantly point to different parts of the sur-rounding heavens, each of them con-tracting and expanding within
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