This notebook was used by Edison during November-December 1918. The entries pertain to experiments with primary batteries, battery components, and the processing of lithium ores. The notes in the first part of the book relate to the construction and performance of twelve experimental cells made with CuO electrode plates of varying types. These experiments are continued in N-18-12-26.1. The performance tests include measurement of amps, as well as tests of fragility by dropping plates. Subsequent entries relate to experiments on processing lithium ores involving lepidolite (lithium mica) and amblygonite. Reagents and procedures are given for each process, along with notations of the presence of a lithium \"line,\"" as indicated by a spectroscope. The lithium experiments are continued in N-18-12-26.2. Also included is a list of organic solutions in which Edison tested the solubility of lithium chloride, along with notes of results from the tests described in N-18-12-21 [not selected]. The lithium experiments probably pertain to the use of LiOH in the electrolyte for batteries. There are also cursory descriptions of experimental cells numbered from 13 to 19. The notes indicate that Frederick P. Ott assisted Edison with the battery experiments, while Ludwig F. (Louis) Ott assisted with the lithium experiments. The front cover is labeled \""CuO Battery Expts & Lithia.\"" The pages are unnumbered. Approximately 120 pages have been used."