"He had been warned that non-theoreticians would be present and that he should phrase his talk in not too technical language. He plunged, nevertheless, into the mathematics of spinor algebras. After about twenty minutes, one of the many experimentalists in the audience had the courage to ask him what a spinor was. Onsager replied, thoughtfully: "A spinor--no, a set of spinors--is a set of matrices isomorphic to the orthogonal group." With that he gave the famous Onsager grin, twinkled his Nordic blue eyes at the bewildered faces around him, and continued the lecture as if nothing had happened."