Journal 1833–1842
p29“Let us not forget that many things are true which cannot be demonstrated by the rules of Watts's Logick. &c”
Fuller, Margaret. "Journal 1833–1842." Houghton Library, Harvard University; bMS Am 1086 (83); Box 5 (83).
Inferred The text explicitly names 'Watts's Logick' Isaac Watts, Logick: or, The Right Use of Reason in the Enquiry After Truth (London: Clark, Mathews, and Ford, 1724) was the standard logic textbook at Oxford, Cambridge, Harvard, and Yale for over a century.