[This note covers all of the notebooks in Group 7: Phonograph Experiments -- Shengle Books.]

This subgroup contains notebooks that relate specifically to the work of John C. Shengle and his assistants in the chemistry laboratory of the West Orange laboratory complex. These books focus primarily on the chemical composition of record cylinders. Books 2-4 contain numbered experiments 666-1045. At the beginning of Book 2 are additional notes on a variety of chemical experiments and analyses dealing with ores, batteries, waxes, and acetylene. Book 1 has not been found.