DIFFERENTIAL geometry is a fascinating subject, because it gives us vivid and picturesque embodiments of theorems obtained by the combination of several branches of pure analysis, such as algebra, function-theory, and the infinitesimal calculus. It presents us with problems of all degrees of difficulty, from the comparatively simple theory of curvature and torsion to the provokingly difficult question of geodesies.
The Elementary Differential Geometry of Plane Curves.
By R. H. Fowler. (Cambridge Tracts in Mathematics and Mathematical Physics. No. 20.) Pp. vii + 105. (Cambridge: At the University Press, 1920.) Price 6s. net.