[volvelle] A Movable Planisphere of the Heavens at Every Minute

Camden, NJ: Henry Whitall, 1871. sixth edition. Good. sixth edition. 15 1/4 inches in diameter. Constructed of a circular cardboard base with black and white printed instructions ("Directory of the Starry Heavens") affixed to the verso, and colored illustrations of the constellations affixed to the recto. Attached to the base is a revolving die-cut frame with instructions affixed with a metal rivet. The upper die cut has been damaged and repaired in several places, preserving most of the text and functionality albeit in a utilitarian manner. There is also some black material that is stuck to portions of the upper die cut. The colored constellation base also has some significant soiling from this black material, including a few places where previous owners have attempted to remove the black material and torn some of the surface off. The colors overall are faded with the yellows and light pinks faded and stronger in some places than others. Some locations have inked-over portions with the intent of strengthening the underlying printing. The instructions on the verso are in excellent condition with some surface soiling and one minor stain.  With all, a working example and priced accordingly.

There are two copyrights on this item, both on the die cut. One notes "Entered according to Act of Congress in the Year 1862 by HENRY WHITALL in the Clerk's Office of the District Court for the Eastern District of Pennsylvania". The other, printed above that and in stronger inking, is "Entered, according to Act of Congress, in the year 1871, by HENRY WHITALL, in the office of the Librarian of Congress, at Washington, D.C." The instructions on the verso note "Sixth edition, Improved"


 . "A planisphere can be regarded as a cheaper and more practical substitute for a celestial globe. Planispheres generally consist of a flat map of the skies, on which a movable disc with a window is fitted. The whole thing is made of board or stiff paper. When the movable disc is set to the desired time, one sees through the window the part of the sky that is visible at that time. Geographical latitude cannot be set, so that a planisphere always has to be used at a particular latitude" (Dekker, p 124)

The sentence "To Astronomy what a Map is to a Geographer" is found at the center of this (and most of Whitall's) planispheres. They are intended as a learning tool for students. Whitall produced many variations of planispheres over the years, some in a square configuration, some [as here] in a circular configuration. The overall sizes varied as well, with examples seen in the 12-13 inch to [as here] 15 inches. Their low survival rate is a testament to how well-used they were.

LITERATURE:
Helfand, Jessica, "Reinventing the Wheel", Princeton Architectural Press, 2002, pp 23-28 (illustrating a circular form by Whitall from 1856 in the Yale Arts of the Book Collection)
Dekker, Elly, et al. Globes From the Western World, Greenwich. London: Zwemmer, 1993. p. 124 (illustrating an 1856 square form planisphere)
Greenslade, Thomas B. Jr. "Planisphere of the Heavens." Instruments for Natural Philosophy, Kenyon College. http://physics.kenyon.edu/EarlyApparatus/Astronomy/Planisphere/Planisphere.html (20 December 2005).