Keynes As "A Puzzling Mathematician"

Where do I recall the quoted phrase in the title from? It's not in Skidelsky:

"Keynes finally saw Roosevelt for an hour at 5:16 p.m. on Monday, 28 May [1934]. No one knows what they talked about. Keynes found the tête-a-tête 'fascinating and illuminating'; Roosevelt told Frankfurter that he had had a 'grand talk with Keynes and liked him immensely'. As always, Keynes paid particular attention to Roosevelt's hands - 'Rather disappointing. Firm and fairly strong, but not clever or with finesse'." -- Robert Skidelsky, John Maynard Keynes: The Economist as Savior: 1920-1937, Penguin (1992)

And it's not in Galbraith, at least here:

"The following year he visited FDR, but the letter had been a better means of communication. Each man was puzzled by the face-to-face encounter. The President thought Keynes some kind of 'a mathematician rather than a political economist.' Keynes was depressed; he had 'supposed the President was more literate, economically speaking.'" -- John Kenneth Galbraith, The Age of Uncertainty