Though vector analysis is most successful in making the elements of a subject attractive, many problems are solved either cumbrously or by a more or less disguised scalar analysis. Rectangular unit vectors i, j, k are often, and very properly, introduced at an early stage, so that even elementary work may look like Cartesian analysis translated into vector notation. Mathematicians are apt to look askance at oblique axes, since they fall between two stools, having neither the simplicity of the rectangular system nor the adaptability and wide projective outlook of homogeneous coordinates.