The James Furnis kept his letter book (179 pages) from July 23, 1755, to December 16, 1758, while serving as British commissary of stores and paymaster to the Royal Artillery and as army comptroller of ordnance in North America. The volume contains 114 letters, all official in nature. He communicated frequently with British officers, independent merchants, and the Board of Ordnance in London, revealing decision-making processes for supplying and managing the Royal Artillery in America. These letters also supply information on troop movements and estimates of dead and wounded.
Furnis wrote the bulk of the entries from Albany and New York City, but also wrote while on short trips to Philadelphia and Boston. Recipients are officers, engineers, and merchants at Albany, New York, Owsego, Fort Edward, Fort William Henry, Boston, and Philadelphia. His letters offer in-depth descriptions of fort upkeep and artillery management and activities. Of particular interest are 24 dispatches from Furnis to the Board of Ordnance in London, which detail the Braddock expedition, describe the poor state of order at Fort Edward, and provide a firsthand account of the siege and capture of Fort William Henry by the French army under Montcalm (August 3-26, 1757).
Furnis wrote the first entry from Fort Cumberland, Maryland, in August 1755, about a month after Braddock's defeat at the Battle of the Monongahela.
- 4 letters from Furnis to John Ewing, an independent merchant in Boston from whom the British Military purchased military stores.
- 7 letters to Major General Abercrombie, including a letter that concerned supplies for Abercrombie's failed attack at Fort Carillon, and the positions of Colonel Williamson, who at that time was laying siege to the French Fort at Louisbourg in Halifax (June 22, 1758).
- A letter to William Saltonstall, commissary of Royal Artillery at Halifax, written during the Siege of Louisbourg (May 79 1758).
- A letter giving a full account of the siege on Fort William Henry, between July 31 and August 10, 1757, with discussions of General Webb, Lord Loudoun, Lieutenant Colonel John Young, and Montcalm, and with notes on the preparations of Fort Edward and Fort William Henry in June (August 27, 1757).
An additional loose letter from John Bradstreet to James Furnis (September 2, 1759, Albany, New York) is located in the front of the volume. In it, Bradstreet asks if artillery, ammunition, and stores sent west have been stopped for want of carts.