The title of this paper is “The Eternal Triangle” ; but titles, like politicians, are sometimes misleading. Only last year, for example, you, Mr. President, skilfully cloaked an address on elliptic arcs under the beguiling title of “The Marquis and the Land Agent : a Tale of the Eighteenth Century”. And so now, Ladies and Gentlemen, any hopes you may have entertained of hearing a new solution of an age-old problem must be abandoned. I cannot even say with George Canning.