“The general phenomena of the tides are explained by the attraction of the sun and moon.” This “quaestio” had been one of the “Theses Physicae” disputed at commencement in 1746 and would be again at JA’s commencement in 1755. See entry of 18 June, above, and note there; MH-Ar: Theses and Quaestiones, 1737–1810.

Samuel Locke (1732–1778), of Lancaster, Harvard 1755, later minister at Sherborn and, from 1770 to 1773, a most ill-fated president of Harvard College (Sibley-Shipton, Harvard Graduates , 13:620–627; see also JA, Diary and Autobiography , 3:260).

The route from Cambridge to Brookline would under normal conditions have been across “the Great Bridge over Charles-River in Cambridge,” built in 1662–1663 and located “at the foot of Brighton Street [now Boylston Street]” (Mass., House Jour. , 29:99; Lucius R. Paige, History of Cambridge, Massachusetts, 1630–1877, Boston, 1877, p. 195). A petition to the General Court in Dec. 1752, however, indicates that the bridge “received such a Shock the last Winter by the Ice” that “a thorough Repair” became an “absolute Necessity” (Mass., House Jour. , 29:99). On 2 July 1753 the Boston Evening-Post gave notice: “Whereas the great Bridge in Cambridge has for some Time past been out of Repair, so that there was no passing over it; This is to inform the Publick, that the said Bridge is now so far repaired, that Chairs, Chaises, and other Carriages may pass over it with Safety.”

The bridge in Watertown, also known as the “great Bridge,” was built in 1718– 1719 and crossed the Charles River near the present Watertown Square at Galen Street (Watertown Records, Watertown and Newton, Mass., 1894–1939, 2:256–257, 261, 263; G. Frederick Robinson and Ruth Robinson Wheeler, Great Little Watertown: A Tercentenary History, Watertown, Mass., 1930, p. 48).

Attendance at exercises being required of all students other than those in the graduating class until 1 July, and senior sophisters not being allowed, while preparing for their “sitting solstices” or oral examinations, to leave Cambridge between 21 March and 1 July (MH-Ar: Corporation Records, College Book No.7, Meeting of 21 May 1753), the last recitation day before 1 July became the appropriate time for a meeting in Hall. On this occasion, attended by the Presi-49dent and Fellows, speakers from the senior class, including a valedictorian chosen by his classmates, would perform (Morison, Three Centuries of Harvard , p. 119). Between this precursor of “class day” and commencement (in 1753 on 18 July) there seem to have been no regular recitations, though the formal summer vacation of six weeks did not begin until after commencement day.

Thomas Oliver (1734–1815), identified by JA as valedictorian for his class, also received Faculty appointment as orator at the morning exercises of commencement in 1753 (MH-Ar:Theses and Quaestiones, 1753, handwritten notation). On him see Sibley-Shipton, Harvard Graduates , 13:336–344, and an article by Oliver Elton, Col. Soc. Mass., Pubns., 28 (1935):37–66.