There have been quite a few such delightful surprises. The conic sections, invented in an attempt to solve the problem of doubling the alter of an oracle, ended by becoming the orbits followed by the planets in their couses about the sun. The imaginary magnitudes invented by Cardan and Bombelli describe in some strange way the characteristic features of aternating currents. The absolute differential calculus, which originated as a fantacy of Riemann, became the mathematical vehicle for the Theory of Relativity. And the matrices, which were a complete abstaction in the days of Cayley and Sylvester, appear admirably adapted to the exotic situation exhibited by the quantum theory of the atom.