Clear and cold. Morning passed in study. Afternoon in a ride. Evening passed partly at the Mansion, partly at Mrs. T. B. Adams’s. Mr. Brooks left us this morning.

Read Locke p. 393–427. Upon adequate ideas, and upon the association of ideas. Curious portions of the operation of thinking. This book of Mr. Locke’s is like opening a new vein of knowledge to my mind which no preceding study of the subject had ever touched. What was the value of my College studies in this department, in which nevertheless my nominal scholarship stood better than in others. The vanity of college education. All I have done in study has been since twenty. Before that I only read and gathered.

Lucretius b. 4. 302–530. I took a long ride almost to the blue hills this evening with my father admiring the green surface of the country which the late rains have brought out.