Diary entries document Jaques' activities when the material was written. They also record his reflections on earlier phases of his life. In the first volume (December 18, 1840 to January 29, 1846), he reviewed the progress of his education and wrote about topics that would claim his attention later in life. He noted that he pursued studies of classics, played the flute, and read a considerable amount of literature. In 1843, he described himself using Orson S. Fowler's ideas about phrenology. Jaques believed he was inclined to underrate himself, had a nervous temperament, was sensitive, prone to sickness, refined, delicate, and eager. Several days later he wondered if he should not lead a life of celibacy and remarked that he wished his father had; Jaques never married. Jaques also provided his opinions on the legal profession and his efforts with the Washington Temperance Society. The second volume of Jaques' diary begins on January 20, 1852 and ends on September 24, 1856. Many of the pages are devoted to describing the legal details of property transfers. His reading habits changed, reflecting his growing curiosity in architecture and travel. By 1854, Jaques was losing interest in his nursery, but he remained active in the profession. In January 1856, he started preparing for a trip to Europe. Upon returning home, he recorded his impressions, comparing Europe to the United States. In general, he found Americans to be lagging behind Europeans.
