This notebook covers the period March-May 1907. All entries are by Edison. The book contains notes regarding projects to be undertaken and hypotheses to be tested, along with other theoretical speculation pertaining to the properties of electricity. Included are entries relating to x-rays and \"xyz rays,\"" the electromotograph, storage batteries, and incandescent lamps. Several of the ideas were tested, and the results are noted by Edison marginalia. The book appears to have been used primarily at Fort Myers, Florida. The front cover is labeled \""Experiments & Theory.\"" The book contains 198 numbered pages.