32 A Comprehensive View

66. A satellite in one of its nodes appearsin the orbit of its primary : in ail otherparts of its orbit it has latitude.

If the plane of any circle produced passesthrough the eye, it appears to be a straightline; consequently every circle, viewed ob-liquely, will appear elliptical; so that

When a satellite is in its node, at thefame time that its primary’s heliocentricplace is in 'the same degree of the eclipticwith it, and the earth in its geocentric node jat that time the orbit of the satellite appearsa straight line. When the primary is in anyother part of his orbit, the satellite’s orbitwill appear an ellipsis, whose shortest axisincreases in proportion as the primary isfarther distant from the satellite’s node.

The orbit of the earth is so small, whencompared to those of Jupiter and Saturn,that in whatever part of her orbit she mayhappen to be, when either of these planetsare in the nodes of their satellites, these lastwill appear to describe lines very nearlystraight.

67. When a satellite is in that semicirclewhich is farthest from the earth, its geo-centric motion is direct; when it is in that

nearest