This is a collection of autograph letters, principally to Hosack, but also between other correspondents.

The only son of Benjamin Franklin, William Franklin served as Royal Governor of New Jersey during the critical years between 1762 and 1776. An ardent Loyalist, William split with his father over their political differences in the early days of the Revolution, and after enduring two years of imprisonment, became a leader in the Loyalist cause. He settled in London in 1782, where he worked as an agent for Loyalist claims. The William Franklin Papers are a miscellaneous assemblage of letters and documents, dealing largely with Franklin's years as Royal Governor of New Jersey. The majority of the letters are perfunctory, however they provide some information on Franklin's land holdings in New Jersey and the Ohio country. The collection includes two letters relating to Franklin's imprisonment in Connecticut during the Revolution, two affectionate letters to his sister Sarah, and one to his son William Temple Franklin.

After emigrating from Germany to Philadelphia in 1796, Peter Adolph Grotjahn established himself within the city's mercantile community, trading opportunistically both inland and coastwise as far as the Caribbean. In 1812, he began publishing a commercial newspaper, Grotjan's Philadelphia Public Sale Reports and he became increasingly active in local Democratic Party politics. The APS copy of Peter Grotjahn's memoir is a typescript copy of an original volume held at the Historical Society of Pennsylvania. Written for his grandchildren, the memoir begins with a relatively brief genealogical discussion, but concentrates on his personal and political life and commercial experiences prior to 1817. The last section of the autobiography was completed posthumously from notes, and includes extracts from Grotjahn's diary as late as 1844.

A collection of business and personal papers of three generations of the prominent Philadelphia Jewish family from 1750-1974. Business records include trade and land transactions (some in Yiddish) of the Gratz brothers, Barnard and Michael (1750-1804) with the business continued by Michael's sons: Simon, Hyman, Joseph, Jacob, and Benjamin (1791-1861). Personal correspondence are primarily letters to Rebecca Gratz from her sisters Rachel and Sarah (1795-1867) with later correspondence to Rachel's children: Horace and Sara Moses (1832-1879). Contains a small group of French letters related to Napoleon III, collected by family member Miriam Fox, and some heirloom artifacts.