(1900 - 1975) British meteorologist attached to the Royal Air Force who notably persuaded Gen. Dwight D. Eisenhower to change the date of the Allied invasion of Europe from 5 to 6 June 1944 after having predicted a lull in the poor weather over the English Channel. Bold signature on a 5.5 x 2.25 in. sheet to which he adds: 'As a member of the British National Committee for the I.G.Y. There is a photograph in Royal Society publication.' Fine.