A treatise on gyrostatics and rotational motion . due to the rolling: of anarrow cone fixed in the earth (and there-fore moving with the earth), having itsaxis coincident with the earths axis, upona cone fixed in space, the axis of which isat right angles to the ecliptic, and the semi-ano-le of which is 23 27 8. This is illus-trated by the diagram, which shows a modelof the earth mounted so as to show theprecessional motion. The former is calledthe body cone, the latter the space upper surface of the Hat ring roundthe stand is the plane of the ecliptic, the• lark line NE is pari of th
A treatise on gyrostatics and rotational motion . due to the rolling: of anarrow cone fixed in the earth (and there-fore moving with the earth), having itsaxis coincident with the earths axis, upona cone fixed in space, the axis of which isat right angles to the ecliptic, and the semi-ano-le of which is 23 27 8. This is illus-trated by the diagram, which shows a modelof the earth mounted so as to show theprecessional motion. The former is calledthe body cone, the latter the space upper surface of the Hat ring roundthe stand is the plane of the ecliptic, the• lark line NE is pari of the equator, PN isa meridian drawn from the pole I to the intersection N of the equatorwith the ecliptic. The point N represents one of the equinoxes or nodalpoints at which the sun in its apparent motion among the stars passesfrom one side of the plane of the equator to the other. Lines drawn fromthe centre (not shown) of the globe to points on the ring shown as situatedparallel to the ecliptic at the top of the model, give the space cone. The. 11 i IXTHODIHTOHV 13 body cone is represented by its upper end P, which is a rod of brass resting n the inner surface of the ring. This rod is a very narrow cone with itsapex also at the centre of the globe, and its axis of figure is of theglobe. With the rod resting on the ring the globe is set spinning aboui 1in the counter-clock direction as seen from above. It will he seen that,while for the ordinary top as shown in the diagram in 10, the body conerolls on the outside of the space cone, the body cone here rolls on the insideof the space cone. The cone P then rolls round the ring, of which it makes one circuit in thetime T. I) /. where T is the time of one turn of the globe on its axis and ]) /the ratio of the diameter of the ring- to the diameter of the cone at P.(Strictly speaking, the ratio should be (D — d) d, but d is very small in com-parison with D.] As the cone rolls round the meridian NP travels with it,and the equin
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Keywords: ., bookcentury1900, bookdecade1910, bookidtreatiseongyrost00grayric
