I'm reading a social history of the Scotch-Irish. It starts out by describing the Lowland Scots in 1600, prior to their emigration to Ulster. The author is at some pains to point out that the Lowlanders were not primarily Celtic in bloodline or culture. In very large part, they were descended from the Angles of Northumbria, who got cut off from the rest of Angel-land when the Vikings invaded. This is why the Lowland Scots speak English, of course. Then comes this footnote:
*The schoolboy's comment, that the acute angles went north while the obtuse angles remained in the south, is probably apocryphal.