PRINCIPAL a.
of a quadric (Geom.), three planes each of which is at right angles to the other two, and bisects all chords of the quadric perpendicular to the plane, as in an ellipsoid. -- Principal point (Persp.), the projection of the point of sight upon the plane of projection. -- Principal ray (Persp.), the line drawn through…
QUEEN n.
wter or britannia, and consisting essentially of tin with a slight admixture of antimony, bismuth, and lead or copper. -- Queen's pigeon. (Zoöl.) Same as Queen pigeon, above. -- Queen's ware, glazed English earthenware of a cream color. -- Queen's yellow (Old Chem.), a heavy yellow powder consisting of a basic mercu…