This undated pocket notebook contains lists of devices, ranging from chalk batteries, electric fans, and lamps to exotic items such as an "odorscope." Some of the listings are accompanied by drawings. The entries are in the hand of Charles Batchelor. They are arranged in alphabetical order, and many of them are initialed by John F. Ott. The front cover is labeled "156." The pages are unnumbered. Approximately 25 pages have been used.