Bulwer was the first Englishman to write about the teaching of deaf-mutes. "Chirologia is often cited as Bulwer’s link to later Deaf studies because it focuses on hand gestures  which have come to be seen as the domain of deaf communication. In fact the book only mentions the deaf in passing. He believed it was Nature's recompense that deaf people should communicate through gesture, "that wonder of necessity that Nature worketh in men that are born deafe and dumb; who can argue and dispute rhetorically by signes" (page 5). The handshapes described in Chirologia are still used in British Sign Language. Bulwer does mention fingerspelling describing how "the ancients did...order an alphabet upon the joints of their fingers...showing those letters by a distinct and grammatical succession", in addition to their use as mnemonic devices Bulwer suggest that manual alphabets could be "ordered to serve for privy ciphers for any secret intimation" (Chironomia, p149). Chirologia is a compendium of manual gestures, citing their meaning and use from a wide range of sources; literary, Religious and Medical. Chironomia is a manual for the effective use of Gesture in public speaking" (Wikipedia). New edition, edited and annotated by James W. Cleary, Carbondale, 1974. Digital facsimile of the 1644 edition from the Internet Archive at this link.