I made acquaintance with Stokes in 1850 at the meetings of the Ray Club. That was a society at Cambridge for the cultivation of Natural Science by friendly intercourse, which had been formed in 1837 in order to fill, so far as that could be done without Henslow's inspiration, the gap left by the cessation of Henslow's weekly receptions of members of the University interested in Natural History. Natural History was still, when I joined the Club, most frequently the subject of conversation at its gatherings, and it may seem surprising that Stokes, who at that time (1850) was best known as a great mathematician, and had just been elected Lucasian professor, should have been a very regular attendant at the weekly meetings of such a Club. Really, however, his bent was to Natural Philosophy, as his work showed, where his great mathematical ability was employed in handling the problems of Nature. His elder brother, William, a fellow of Caius, had been one of the original promoters of the Club, and was a mineralogist and a chemist with whom I fraternised at once; but I very soon found that George Stokes was equally interested in the same subjects, and quite as ready to discuss, with a beginner, questions connected with them on which probably his own conclusions had been reached by a much shorter induction.