This notebook covers the period March-September 1880. Most of the entries are by Charles Batchelor. There are also entries by Edison and John Ott Most of the material relates to the development of the carbon filament lamp. Included are notes, calculations, and drawings of machines for cutting and molding the filaments, for making clamps, and for rolling connection wires; notes, calculations, and drawings of filament designs and vacuum experiments; and lists of carbonized materials. There are also notes, calculations, and drawings of the electric railroad; a draft letter from Edison to Babcock and Wilcox concerning steam boilers; a draft letter from Batchelor to Franklin H. Badger concerning telephone central exchange systems; and a short list of publications. The label on the front cover was originally marked \"LAMPS Beginning Mch 29th 1880.\"" Later a \""C\"" was added to make it \""CLAMPS.\"" The book contains 283 numbered pages.

Blank pages: 128-129, 192-193, 250-263, 266-267.

Missing page numbers: 157-158, 279-282."