1890 - 91 .] Lord M‘Laren on Glisseite of Two-term Oval. 87 
curve and the coordinates of its tangents, normals, and radii, and 
the required equation is found by elimination between two equations, 
one of which is of the 1st degree. Other curves of the same system 
exist, and their equations may be found, e.g., the locus of the 
intersection of normals, where a curve moves in contact with rec- 
tangular guides. Here the coordinates, x and y , are the differences, 
Pi-7ff 2 and i? 2 _2sr i i Pi> Pz being the perpendiculars drawn from 
the pole of the curve to the tangent guides, and zsq , being the 
perpendiculars drawn from the pole to the normals. 
