An elementary treatise on trilinear co-ordinates : the method of reciprocal polars, and the theory of projections / by the Rev. N.M. Ferrers ... Trilinear co-ordinates. Ferrers, N. M. (Norman Macleod), 1829-1903. Conic sections. Reciprocal polars. QA552 .F4 1876 516 FEE London : Macmillan and Co., c1876. c1876. 1876 Text xiv, 184 p. eng