Secret of the River by Fred M. White

Tom Blissett and his popular wife had not been so many years in residence in the neighbourhood. Blissett was quite a young man, not yet in the forties, and a thorough sportsman in all departments of the game. He had been, ages ago, or so it seemed now, captain of a famous public school where he and Nevil were educated, from whence he had graduated as a bachelor of science at Oxford, and thence to Harley-street, where he had finally become recognised as a scientist of distinction. His ambition had been greater than his strength, so that a complete nervous breakdown had followed. On the top of this, a distant relative had left him a small fortune, and with the money behind him he had determined to turn his back on London and devote himself, for the future, to his farm and his sport. The result was a return to perfect health, and a resolve that the world of science should know him no more.

All the same, he did a lot of reading in his spare time, and kept himself thoroughly abreast of modern scientific developments. But nobody would have known this who had not been acquainted with his past, for he kept the matter severely in the background, and one of the few people in his secret was Nevil Ashdown.