ELLIPSOID
, is an elliptical spheroid, being the solid generated by the revolution of an ellipse about either axis. See Spheroid.
ELLIPTIC or Elliptical, something relating to an ellipse.
Elliptic Compasses. or Elliptical Compass, is an instrument for describing ellipses at one revolution of the index. It consists of a cross ABGH (fig. 8.) with grooves in it, and an index CE, sliding in dovetail grooves; by which motion the end E describes the curve of an ellipse.
Elliptical Conoid, is sometimes used for the spheroid.
Elliptical Dial, an instrument usually made of brass, with a joint to fold together, and the gnomon to fall flat, for the convenience of the pocket. By this instrument are found the meridian, the hour of the day, the rising and setting of the sun, &c.
Elliptoide, an infinite or indefinite Ellipsis, defined by the indefinite equation when m or n are greater than 1: for when they are each = 1, it denotes the common ellipse.
There are several kinds or degrees of Elliptoides, denominated from the exponent m + n of the ordinate y.
As the cubical Elliptoide, expressed by ; the biquadratic, or sursolid ; &c.
