New Special Collections and University Archives book purchase: Unconstructed volvelle

Over the last ten years, Special Collections and University Archives has acquired several books with moveable parts, including books with volvelles, a type of wheel chart that uses rotating parts to allow the reader to make calculations. They were used in early printed books across a range of subjects, including astronomy, cryptography, navigation, and many others. See, for example, this blog post on a book using volvelles to identify holy days and other calendar-related calculations related to solar and lunar calendars. Or this post on a book that uses volvelles to make geographical calculations for the northern and southern hemispheres of the earth. 

Now, with a newly acquired book, readers can see what a volvelle looked like before it was put together! The book is titled in Latin, De cognoscendis, et medendis morbi ex corporum coelestium positione Libri IIII. The English translation is On the knowledge and cure of diseases from the position of the heavenly bodies, Book IV. It was written by Johann Virdung, a German physician and practitioner of astrological medicine and published in Venice in 1584. According to Virdung, in order to treat a patient with an ailment, the physician must first create a chart of planetary influences over the patient, map those influences onto the body, and then create a treatment plan using the appropriate medications based on their planetary correspondences and timing the treatment when the moon and planets are favorable. The book was to include a volvelle to assist with the creation of the chart.  

This copy of the book includes a sheet of paper bound into the book on which are printed the various layers of the volvelle with instructions for assembly. The volvelle was to be affixed to the back (verso) of leaf 28 of the book, on which the base wheel, divided into 24 hours, was printed onto the page in the middle of the text. The separate sheet includes four options for the 2nd layer, the horizon wheel. The book owner was to select the one that most closely matched the latitude in which they lived. The third layer is the zodiac wheel, showing the twelve signs of the zodiac. The final layer is a small ruler that rotates across all the wheels and helps the user read the final calculation. The layers were to be affixed in the center with a thread or pin so that each layer could rotate freely. 

This tells us that the book owner was intended to be the one to cut out and assemble the volvelles—which makes sense in this case especially, where the instrument is designed to be customizable based on location. We also get some insight into the printing process for this book. The paper on which the layers are printed is larger than the pages of the book, so it was typeset and laid out in the bed of the printing press separately from the printing of the pages of the book. When it was bound in which the pages of the text, it had to be folded to fit. 

Putting this book side-by-side with one of the books with an assembled volvelle, it is illuminating to see how deeply the reader was interacting with these moveable books—both in assembling the instruments themselves and using them to make calculations. 

This book will be cataloged over the next several weeks and then will be available to use in the reading room of Special Collections and University Archives later this semester.