#SMALL PLUMB BOB PORTABLE#

The underside of the compass box, a later replacement to the sundial, is also decorated with a six-pointed star. This meant it would have worked not only in Europe but across the range of French territory in North America.īourgaud sundial, bottom view. The French pocket sundial shown here has three hours scales and a gnomon whose angle can be adjusted from 30 to 55 degrees. Each latitude required a different hour scale because the sun would be at a different angle higher or lower in the sky at each location at noon or any other given hour. Some of these dials, like the one above, had a shadow-casting component (called the gnomon) that could be adjusted according to the latitude of the observer.

#SMALL PLUMB BOB PORTABLE#

Portable sundials date to antiquity, and by the 1600s, a few Europeans carried sundials that fit in the pocket.

The length of the day varied with the latitude of a location and the time of year, while the hour depended on the local longitude-time zones embracing a range of longitudes would not be introduced until the late 1800s. They came to be found in public squares, on the walls of churches, in gardens of the well-to-do, and in observatories. Early examples were made in Egypt, Babylon, and China. Sundials date at least to around 1500 BCE. From ancient times, people have used changes in the lengths and directions of shadows cast by objects in the sun as a measure of time. ( MA.325565)įirst, a bit of background on sundials. Pocket sundial by Bourgaud of Nantes, 1660–1675.

Small plumb bob