This notebook covers the period January 1888-June 1889. It was used by D. T. Marshall to record notes regarding carbonization of gas light mantels, the production of chlorine by electrolysis, insulation experiments, and various chemical analyses. Near the end of the book are drafts of two letters, probably to Edison General Electric Co., relating to samples of insulation sent for testing to the West Orange laboratory. The spine is labeled "46." The pages are unnumbered. Approximately 90 pages have been used.

Only the material relating to gas light mantel and insulation experiments has been selected.