This notebook is a continuation of N-18-11-26. It was used by Edison during the period December 1918-February 1919 for notes on processing lithium. Among the ores used for experimentation are lepidolite (lithium mica), amblygonite, and spodumene. The entries describe different fusing, filtering, and leaching steps, along with the reagents employed, and note the presence of a lithium "line" as indicated by a spectroscope. 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 notes indicate that Ludwig F. (Louis) Ott assisted in some of these experiments and performed assays on some of the final residues. The front cover is labeled "Lithia Dec 26 1918." The pages are unnumbered. Approximately 100 pages have been used.