What is important for mental relaxation, apparently, is not that a man shall try to set his mind at absolute rest, for that seems to be impossible, if a man really has a mind; nor that he shall occupy it with trivial things (because his interest will not be caught by them and will revert to the last serious thing that he was doing), but that he shall have an outlet for mental activity in entirely another direction from that to which he usually devotes himself. In other words, it is important that a man shall have a hobby, and that he shall ride that hobby whenever his ordinary business, whatever that may be, will permit him, and the more interesting the hobby, the better.