was an attempt to replace degrees by decimal "degrees" in France and nearby countries, where the number in a right angle is equal to 100 gon with 400 gon in a full circle (1° = gon). This was called or grad. Due to confusion with the existing term grad(e) in some northern European countries (meaning a standard degree, of a turn), the new unit was called in German (whereas the "old" degree was referred to as ), likewise in Danish, Swedish and Norwegian (also gradian), and in Icelandic. To end the confusion, the name gon was later adopted for the new unit. Although this idea of metrification was abandoned by Napoleon, grades continued to be used in several fields and many scientific calculators support them. Decigrades () were used with French artillery sights in World War I. An angular mil, which is most used in military applications, has at least three specific variants, ranging from to . It is approximately equal to one milliradian ( ). A mil measuring of a revolution originated in the imperial Russian army, where an equilateral chord was divided into tenths to give a circle of 600 units. This may be seen on a lining plane (an early device for aiming indirect fire artillery) dating from about 1900 in the St. Petersburg Museum of Artillery. See also Compass Degree of curvature Geographic coordinate system Gradian Meridian arc Square degree Square minute Square second Steradian Notes References External links , with interactive animation Units of plane angle Imperial units Mathematical constants Customary units of measurement in the United States