This subsidiary ledger covers the period March 1908-July 1916, although most of the entries are from 1912-1916. It consists of accounts, arranged alphabetically, for various experiments at the laboratory, along with accounts for Glenmont. Entries for experimental expense accounts include the project numbers assigned in laboratory record books N-01-03-15 and N-10-07-26. The totals for these accounts were posted monthly to General Ledger #9 under the heading, "Experimental Accounts." There is an alphabetical index, which also includes the account numbers in Experimental Expense Ledger (1908-1912). The front cover is stamped "Experiment Ledger No. 9 Thomas A. Edison." A tag attached to the spine is inscribed "Experiment Ledger #9 Thos A. Edison from 1908/1916." The pages are unnumbered. Approximately 600 pages have been used.