Konrad Kyeser's Bellifortis

[Jorge_Stolfi]

Why the odd collection and not the standard 12?

What do you mean?  

It seems almost certain that the Zodiac section had a total of 360 labels, divided into 12 "signs" of 30 labels each, except that two of the "signs" ("Aries" and "Taurus") were split into four diagrams with 15 labels each. 

But two of the "signs" that should have been at the end of that section, presumably labeled "December" ("Capricorn") and "January" ("Aquarius"), apparently got lost.  The folio numbering (which was added when the book was (re)bound, a century or more after it was written) jumps from f73 (last of Zodiac) to f75 (first of Bio), and there is a stump where the missing folio was apparently cut out.

All the best, --stolfi