The Charles and Thomas, Jr. Parsons Papers contain correspondence and shipping papers of the Parsons family shipping business. The shipping papers are particularly detailed, covering the provisioning of the vessels prior to departure, accounts of individual "adventures," and current prices of commodities in various ports in Europe. Much trade was done in the Spanish ports and in the Russian ports of St. Petersburg and Cronstadt. The collection has been divided into two series.

Series I. Correspondence and Accounts contains correspondence from Thomas, Jr. and Charles Parsons to their father, Captain Thomas Parsons. These are business letters, for the most part, giving details about the cargos, the going prices of commodities in each port, and progress in the purchase and sale of goods. It also contains the correspondence of Charles C. Parsons, Boston shipping merchant and agent for the Parsons, relating news of incoming ships, commodities prices and disposal of cargo. Letters to and from Captain Thomas Parsons also relate to the family shipping business. There are a few letters to Judith Parsons, Captain Thomas Parsons' wife. Folder 13 contains a notebook of Captain Thomas Parsons, with recipes for various varnishes, wood, and metal treatments and boat designs. It is not clear whether the account book in Box 1 Folder 13 is the work of Capt. Thomas or of Thomas, Jr. Although Folder 18 of Box 1 contains miscellaneous papers of Thomas Parsons, it should be noted that, given the late dates of the papers, that the person referred to is neither Captain Thomas nor Thomas Jr.

Series II. Ships' Papers contains the shipping papers of the brig Garland and several other vessels. Some letters are from "adventurers," investors placing goods on board the Garland to be sold or traded by the captain for maximum profit. The paper of the schooner Martin (B3 F7) include a deposition of Captain Thomas Parsons describing the Martins' capture and condemnation by a French privateer, and appeal by the owners to the United States government for indemnification under the "Spanish Treaty," and the statement of award. The papers of the brig Halsey (B3 F4) describe damages sustained during a violent storm.