Sixteenth century manuscript volvelle

This is a unique and beautiful handmade and illustrated pocket manual for a physician-astrologist to understand and define the influences of the zodiacal signs on the diseases and the parts of the human body. In excellent condition, it consists of a full calf cover containing 2 leaves in parchment (a bifolium folded and sewn in the middle), one leaf with a 3-wheel volvelle, altogether measuring 115x145 mm, with Latin text in red and black, and dating to the end of the 16th century.

A volvelle is a type of rotating wheel chart with sliding parts constructed of paper that date back to Arabic treatises on humoral medicine c.a. 1000 CE. It is considered to be an early example of a paper analog computer. Medical volvelles, such as this one, are extremely rare.

This volvelle would have been used to predict the best time to provide medical treatment and by the end of the 1500s physicians, by law, would use it to calculate the position of the moon before carrying out surgery. In addition to the 3-wheel volvelle, there are 2 "hands" depicting phases of the moon. The outermost wheel is labeled with astrological symbols, the middle wheel contains the days of the month and a black orb representing the moon, and the inner wheel contains geometric lines and a cut-out circle. When the inner wheel is rotated, various phases of the blackened moon appearing in the middle circle can be viewed within the cut out. Additional parchment pages describe zodiac signs, diseases, organ systems, and on a page labeled "The twelve signs of the moon and evil ("et mali luna duodecum signa"), therapies such as phlebotomy (phlebotomia) and baths (balnea).

Contributed by anonymous