Mathematical notebook attributed to Thaddeus Mason Harris, ca. 1787

Hardcover notebook containing handwritten transcriptions of rules, cases, and examples from 18th century mathematical texts. The author and purpose of the volume is unclear, though it has been connected with Thaddeus Mason Harris (Harvard AB 1787). Most of the entries include questions and related answers, suggesting the notebook was used as a manuscript textbook and workbook. The extracts appear to be copied from John Dean's " Practical arithmetic" (published in 1756 and 1761), Daniel Fenning's "The young algebraist's companion" (published in multiple editions beginning in 1750), and Martin Clare's "Youth's introduction to trade and business" (extracts first included in 1748 edition).

Thaddeus Mason Harris' working documents regarding subject-based library catalog, ca. 1790

Thaddeus Mason Harris, who served as interim librarian of the Harvard College Library in 1787 and as its librarian from 1791 through 1793, is believed to have created these notes while helping compile the library's first printed subject-based catalog. The catalog, Catalogus Bibliothecae Harvardianae Cantabrigiae Nov-Anglorum, was published in 1790 and represented a significant change in approach to the cataloging of the library's collections, which had formerly been cataloged alphabetically. These documents, many of them on small scraps of paper, contain the titles and bibliographic information of books on a range of topics, from "Anatomici" to "Rhetorica."