Humboldt State University ® Department of Chemistry

Richard A. Paselk

Navicula or "Little Ship of Venice" Dial

This dial is a favorite because of its charming shape. This in spite of the fact that it is fundamentally flawed as a time keeping device. But hey, who uses a sundial anymore for accurate time?
The ship's dial may be readily fabricated of brass etc. The main decision to be made by the maker is whether to layout the dial via calculation or to simply copy the scales etc. from a printed model or photograph. If you want to do the "proper job" and calculate your layout get a copy of Fine's Second Book of Solar Horology as interpreted by Peter Drinkwater (references). Drinkwater's translation/interpretation not only gives the information to layout this and other dials, it also tells you their problems.
Alternatively you can copy the layout from a known example. The most readily available is from Gentleman's Magazine, on pg 49 of the January 1787 issue. As this magazine was very important in literary circles it is available on microfilm at many libraries. For convenience I have included scans of the note and the illustrations of both the front and the back of the instrument. You may want to obtain hardcopy due to the better resolution available. Photographs of two example navicula are available on Epact the on-line catalog of Medieval and Renaiance instruments held by four of the World's great museums of the history of science, one at the Instituto e Museo di Storia della Scienza, Firenze, the second at the Museum of the History of Science, Oxford.

Instruments Medieval Science & Scientific Instruments


© R. Paselk
Last modified 14 March 2001