This notebook covers the period January-March 1880. Most of the entries are by Charles Batchelor. A few entries are by Edison. The name Martin Force appears occasionally as a witness. Most of the material relates to the development of the carbon filament lamp. Included are notes, calculations, and drawings of filaments and clamps; drawings and notes on carbon molds; notes and drawings relating to a series of carbonization experiments; and a few notes and drawings of dynamos. The book contains 192 numbered pages followed by 12 unnumbered pages. The pagination is irregular. In the first part of the book only the right-hand pages are numbered; for pages 94-116, only even numbers are used. A few pages near the middle of the book lack numbers.

Missing page numbers: 125, 135, 178.