Subseries C. Shipping and Merchant House Correspondence is organized into four sub-subseries. The merchant house correspondence contains correspondence, accounts, and ship's papers for cargo shipped by the house. The correspondence, arranged alphabetically by name of the firm, has been divided into the correspondence of Richard (1712-1783), Elias Hasket (1738-1799), and of the grandsons: Elias Hasket Jr. (1766-1826), John (1767-1831), and Ezekiel Hersey (1772-1852) Derby. The majority of the correspondence in the latter groups is to John, either while he was in business with Benjamin Pickman, John Prince, Samuel G. Derby, or by himself. One folder (box 14, folder 5) contains letters to John Prince and Benjamin Pickman, sons-in-law of Elias (1739-1799) and partners of the Derbys in many shipping ventures. See Appendix II for a detailed listing of major merchant houses that the Derbys employed, and their locations.

The miscellaneous shipping correspondence (box 9, folder 8) includes letters of instruction and captain's correspondence as well as letters regarding cargo and general shipping business. Correspondence that deals with more than one vessel or appears to discuss more than the specifics of a case is located in the folder of spoliation claims (box 9, folder 9). Of special interest among the spoliation claims is the correspondence with John Gardner, 1761-1765, which refers to the corruption in the claims court, and the protest from Elias Hasket Derby (1739-1799) regarding duties on tea.