In 1908 Francis Galton published his autobiography “Memories of My Life”, and he presented an anecdote he heard from Herbert Spencer. No date was specified for the episode:
Spencer, during a pause in conversation at dinner at the Athenæum said, “You would little think it, but I once wrote a tragedy.” Huxley answered promptly, “I know the catastrophe.” Spencer declared it was impossible, for he had never spoken about it before then. Huxley insisted. Spencer asked what it was. Huxley replied, “A beautiful theory, killed by a nasty, ugly little fact.”
Know Thyself 