A volume comprising undated manuscript notes on chemistry kept by Christopher Heydrick. The spine of the volume reads: Wistar's M.S. Lectures. The name Christopher Heydrick appears on the flyleaf. A letter, tipped in and dated August 2, 1790 precedes the notes. The letter is from M.C. to Christopher Heydrick, and refers to words in the volume that are unclear. This letter provides the date. Text varies, from recto and verso, to recto only, or verso only. First section is titled: History of Chemistry.