ONE of the most delightful books in my father's library was White's "Natural History of Selborne." For me it has rather gained in charm with years. I used to read it without knowing the secret of the pleasure I found in it, but as I grow older I begin to detect some of the simple expedients of this natural magic. Open the book where you will, it takes you out of doors. In our broiling July weather one can walk out with this genially garrulous Fellow of Oriel and find refreshment instead of fatig