154 apsides Or apsis

One of two points, A, A, of an orbit, oval or ellipse farthest from the axis, or the two small dots.

155. Chord.—A right line, as A, uniting the extremities of the arc of a circle or a curve.

123 Valley Roof 156 convolute (see Also involute) facebooktwittergoogle_plusredditpinterestlinkedinmail