This notebook was used by Leroy E. Briggs during July-September 1914 for experiments on miner's safety lamps. The first entry includes a list of things to do and questions to ask in pursuing improvements to the lamp. The following entries consist of daily logs of Briggs' activities and experimental work, including battery tests for locomotive headlights. Some of the notes mention suggestions made by Edison, such as trying different methods of using safety springs on a lamp or using different brass bulbs. Other entries include detailed information on Briggs's conferences with Edison regarding these experiments. The front cover is labeled "Thomas A Edison Lab. Book No. 4 Mine Lamps L. E. Briggs." The pages are unnumbered. Approximately 75 pages have been used. Courtesy of Thomas Edison National Historical Park.