Ancient Navigation European Compass and Sundail

Sundial and Compass, France

This combination sundial and compass, most likely a product of seventeenth-century France, functions through two prominent scientific technologies: one that measures time and another that measures location. These two measurements used in combination can provide a complete understanding of a person’s physical and temporal place in the world. Grasping these concepts was of great interest to Europeans at the time of this instrument’s manufacture.

Throughout the fifteenth to early seventeenth centuries, an era deemed the "Age of Exploration," European nations developed a fervent interest in travel as a means to expand trade routes and develop new trade partnerships. It is during this time period that Europeans discovered the Americas and established large-scale colonial networks. The heavy reliance on scientific instruments for ship navigation during this period increased interest in compass and sundial technologies.

History of Sundial Technology 

Sundials are often considered the first scientific instruments, dating back to inception as early as 3500BCE in Egypt. Sundials utilize the measurement of the positions of shadows produced by the sun to determine time of day. Ancient Egyptians initially used shadow clocks or obelisks, which are monumental vertical columns that cast shadows of various lengths and positions depending on the location of the sun. Over time, this primitive sundial technology expanded into other cultures, including the Chinese, Greeks, and Romans, where it was further refined. In addition to the use of an object (technically a "gnomon") that produces a shadow, more advanced sundials rely on a flat dial plane on which times of the day are marked, similar to the face of a clock.

Sundials remained the dominant time-keeping tools until well into the eighteenth century when more convenient clock and wristwatch technology was first developed. These new mechanisms, unlike sundials, could be used indoors and at night without the presence of natural sunlight. During the decades of their initial development, however, clocks depended on sundials against which they could set and measure "true" time.


History of Compass Technology 

Compass technology is used to indicate physical direction. It dates back to the Qin Dynasty in China from 221 to 206BCE when the Chinese first discovered the magnetic properties of lodestones (naturally occurring pieces of iron oxide which attract iron). When a piece of lodestone is freely moving, it reacts with the Earth’s natural magnetism. The Chinese developed this concept further into the magnetic compass by the twelfth century CE, which was soon after brought to Europe likely via the Silk Road trade network. In this more advanced form of technology, a needle is magnetized by a lodestone and positioned upon a pivot around which directional bearings (north, south, east, and west) are marked. The needle reacts with the Earth’s magnetic field and aligns itself pointing toward magnetic north, thus providing a fixed reference point for the compass’s user.

Further technological developments have been made in terms of compass accuracy since the tool's initial development. For example, scholars noticed that the "north" to which a compass needle points is not precisely the same as the geographic North Pole, and it is also not a static point. Scientists now understand that the Earth’s polarity does not run parallel with longitude lines and shifts gradually over time. One must calculate the magnetic declination angle (the angle of error between magnetic north and true geographic north) in order to determine an exact location. Because of this complication involved in compass use, large modern-day ships and airplanes use gyrocompass technology, a function of measurement developed in 1852 that works in conjunction with the Earth’s rotation rather than its magnetism. Additionally, GPS (Global Positioning System) technology, developed and refined in the 1990s, is increasingly utilized in navigation today. This technology uses analysis of satellite signals and time delays to pinpoint an exact position on Earth. Compass technology has not become obsolete for contemporary use.  It can be used in conjunction with a GPS reading to provide direction at a given location. Because a compass is powered by an automatic response to Earth’s magnetism, it also serves as a general standby when wind, state of visibility, or lack of an energy source inhibits the use of more dependent technologies.


The 'Weldon' Pocket Compass and Sundial

The compass-sundial has a lid and a hinged gnomon/style to make it portable. The sundial plate displays roman numerals and is cut away to a 5mm outer edge, allowing the compass rose to be viewed through a glass cover. The compass rose is divided into the basic 16 wind rhumbs with a separate dial showing 360°. North is marked by a fleur-de-lys .The centre of the rose shows a 32-point star. A blue metallic double needle points to both north and south with gold letters denoting both directions.

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