The other day Kate Morant, author of the interesting Halley’s Log Blog, tweeted the following question on my twitter stream:
Help! My iPhone diary’s become corrupted. By month ok, but by list all the apptmts randomly reassigned to diff dates. Any tips?
Being the friendly and helpful chap that I am, I tweeted back:
Buy a pocket diary (a great Renaissance invention) and a pencil.
Now I have already written about the origins of the pencil, another great Renaissance invention, in an earlier post so I thought it would be nice to write something about the scientific origins of the pocket diary.
Most people know that the printing of books with moveable type was (re)invented by Johannes Gensfleisch zur Laden zum Gutenberg in Germany in the middle of the fifteenth century. (Moveable type printing had been invented twice before in China, eleventh century, and in Korea, thirteenth century) What most people don’t know is that one of Gutenberg’s first pieces of commercial printing was a single sheet wall calendar, which also counts as the earliest known printed scientific publication. Those not in the know are probably thinking why is a calendar a scientific publication?
In the Renaissance one of the dominant forms of medicine was astro-medicine, that is medical diagnosis and treatment based on astrological phenomena. Calendars contained the phases of the moon and other astronomical information, such as planetary conjunctions, to help physicians determine the auspicious and inauspicious days for treatments such as bloodletting and cupping. The importance attached to this information can be judged by the fact that many towns and districts employed a mathematician as an official calendar maker, whose function was to deliver this astronomical data for the physicians, barbers and surgeons of the town.
Astronomers and astrologers also produced and used ephemerides, which are more complex tables giving the daily positions of all the heavenly bodies. In the 1470s Regiomontanus set up the first scientific publishing house in Nürnberg and amongst other astronomical and astrological texts published the first printed ephemerides and astronomical/astrological calendars in book form. The calendars were simplified versions of the ephemerides with a reduce amount of data. Both publications proved immensely popular and were quickly copied by many other printer publishers.
We have several well-attested examples of astronomers and astrologers using their ephemerides to note important occurrences in the margins at the relevant date. For example the Nürnberger astronomer/astrologer Johannes Schöner recorded the birth of his children in the margins of his ephemerides.
At some point an enterprising printer publisher came up with the idea of binding empty pages into their book form astrological medical calendars between the printed pages providing a space were the users could make their notes instead of having to use the margins. This simple novelty caught on and the pocket diary was born. A vestigial reminder of the origins of the pocket diary can be seen in the phases of the moon that are still included in almost all diaries. These are not there so you remember to go out and marvel at the full moon but to help you to determine the correct day to indulge in a bit of bloodletting to cure the fever that accompanied that dose of flu you picked up at the office party.