This ledger covers the period August 1878-February 1880. It contains accounts payable and receivable, along with records of cost accounts, labor accounts, royalty accounts, and personal accounts. The cost accounts list expenditures on various projects (including the experimental electric light and dynamo) over long periods of time. Construction costs are also recorded in this manner. The royalty accounts list payments from the Gold & Stock Telegraph Co. and other companies to individuals at the Edison laboratory. There is also a record of salary payments made by Western Union to Edison. The accounts payable and receivable refer to a broad range of Edison companies and experimental ventures in Europe and in the Americas. The spine is labeled "Ledger T.A.E" and "3." The book contains 693 numbered pages and an index. Approximately half the pages are blank. Courtesy of Thomas Edison National Historical Park.