Hero’s Pneumatics original: "Heronis Spiritalia." This refers to the famous treatise on vacuum, air pressure, and mechanical automata by the 1st-century engineer Hero of Alexandria.

304
These numbers represent the library shelfmark: Magl. 1.6.304.

Hero An ancient Greek mathematician and engineer from Alexandria, known for inventing the first steam engine and various hydraulic machines., Pneumatics The study of the mechanical properties of air and other gases; in this context, the title of Hero's primary work on the subject., shelfmark A unique code used by a library to identify a book's physical location on its shelves.