Angular Mil - History

History

The milliradian was first invented in the mid nineteenth Century by Charles-Marc Dapples (1837-1920), an engineer and professor at the University of Lausanne. Degrees and minutes were the usual units of angular measurement but others were being proposed, with 'grads' (circle/400) under various names having considerable popularity in much of northern Europe. However, Imperial Russia used a different approach, dividing a circle into equilateral triangles and hence 600 units to a circle.

Around the time of the start of World War I, France was experimenting with the use of milliemes (circle/6400) for use with artillery sights instead of decigrades (circle/4000). The United Kingdom was also trialling them to replace degrees and minutes. They were adopted by France although decigrades also remained in use throughout World War I. Other nations also used decigrades. The United States, which copied many French artillery practices, adopted mils (circle/6400). After the Bolshevik Revolution and the adoption of the metric system of measurement (e.g. artillery replaced 'units of base' with metres) the Red Army expanded the 600 unit circle into a 6000 mil one. Hence the Russian mil has nothing to do with milliradians as its origin.

In the 1950s, NATO adopted metric units of measurement for land and general use. Mils, metres and kilograms became standard, although degrees remained in use for naval and air purposes, reflecting civil practices.