Volvelles in the McGregor Library

Definition from John Carter, ABC for Book Collectors

Several volumes recently scanned as part of the McGregor Foundation’s digitization grant feature volvelles. And what is a volvelle? At its simplest, a volvelle comprises multilayered discs or dials that rotate above the page. The parts of the volvelle were printed on dedicated pages so that the reader could cut, remove, and assemble them on the appropriate page within the text using decorative glue caps or string. The earliest volvelles are attributable to Matthew Paris, an English Benedictine monk responsible for the 13th-century manuscripts constituting the Chronica Majora, and Ramon Llull, whose 1302 manuscript Ars Magna currently resides in the British Library.  These and other early volvelles were designed to answer both simple and complex questions related to religion and mysticism.  By the fifteenth and sixteenth centuries, however, volvelles were appearing in astronomy and geographic texts, providing efficient summaries of data or serving as simple calculators.

In the McGregor Collection

Four of the first fifty volumes scanned from the McGregor collection contain volvelles:  three editions of Peter Apian’s Cosmosgraphicus and the revised edition of the Arcano del Mare of Sir Robert Dudley.



Cosmographicus Peter Apian (“Petrus Apianus”) published Cosmographia in Bavaria in 1524.  An introduction to astronomy and geography, it remained one of the most popular books throughout the century. The first edition featured four volvelles: a device for determining the horizon line, an altitude sundial, a meridian device, and a lunar clock.  A revised edition published in 1545 by Gemma Frisius, an astronomer and instrument-maker in Louvain,  replicated all of the original volvelles.  When Frisius published a second edition in 1550, however, he added a fifth: a nocturnal, an instrument for determining the time by observing the position of certain stars.  The importance of the volvelles to the popularity of the Cosmographia is open to debate.  The Collection also features an abridgment of the book published in Paris that omitted them entirely.




Arcano del’Mare.  Sir Robert Dudley’s Dell’Arcano del Mare (On the Mystery of the Sea) was the only successful maritime encyclopedia in the 17th century that did not originate in the Dutch Republic. The initial four-volume publication (1646-1647) was groundbreaking: “it was the earliest printed sea atlas to cover the entire world; the first compiled by an Englishman; and the first to base its charts on the map projections used by Mercator” (C. Rider). For Dudley, the volvelles were important navigational tools.  In the two-volume revised edition published in 1661 owned by the McGregor Collection, the general maps are gone, but the charts and volvelles remain.