This notebook covers the period April-November 1886. All of the entries are by Edison except for one set of notes and drawings by John F. Ott relating to carbon filament experiments. Most of Edison's notes concern fundamental magnetism experiments, including the determination of the Earth's magnetism and the lines of force of the various planets around the sun. Other notes and drawings deal with quadruplex telegraphy, the phonoplex, telephones, and dynamos. Included also are a set of notes by Edison labeled "Reasons against an Alternate Current Converter System" and some calculations regarding the cost of flowers and other plantings for Edison's property at Fort Myers. The first page of the book is stamped "Laboratory of T. A. Edison, 292 Avenue B cor. 17th St." There are 294 numbered pages. At least one page at the end of the book has been torn out.

Blank pages: 8-9, 122-125, 266, 269.

Missing pages: 267-268, 271-272.