Oxford botany

From

Philosophical papers -
Friedrich Waismann - 1977 -

"The notebooks in which his linguistic
botanising was recorded come into play
with a long list of the first occurrences,
as registered by the OED."

(for words like 'frigthening', etc.)

This is from Brian McGuiness's introduction. Of course McGuinness knew all about it via D. F. Pears, who had been tutee of Grice.