This notebook covers the periods April 1886 and May 1887. There are also a few undated entries in between. All of the entries are by Edison. Many of them deal with the rotation of the earth and other planets around the sun and the resulting lines of magnetic force and electricity, which, Edison theorized, were responsible for gravity. There are also numerous entries relating to spectroscopy and to fundamental experiments on magnetic fields. Other notes and drawings concern the grasshopper telegraph, electric meters, arc lights, electric power distribution, pressure indicators, armature design, telephones, and the direct conversion of heat into electricity. Included also are notes about experiments to be performed at the new laboratory in Edison's lamp factory (see Lamp Factory Notebooks). One unlabeled set of drawings may pertain to ore separation. The first page contains the notation: "Fort Myers Florida Aug 17 1886 Ideas T A Edison." The book contains 288 numbered pages.

Blank pages: 128-129, 136-137, 142-143, 286-287.

Missing page numbers: 95-96, 103-122.