I couldn't resist your request for a definition of a Mil: this is the angle created by a right angled triangle with length ratio 1000:1, i.e. 1m at a range of 1km. In trigonometric terms this is a milliradian and there are 2 x pi of these radians in a full circle, or 2 x 3.14159 ... etc. A reasonable approximation to this is 6400 milliradians in a full circle and this number is used for military compasses. Hope this helps. - Submitted by N Calder

A Radian is an angle measured at the centre of a circle between two radii and the same length as the radii measured around the edge of the circle. An equilateral triangle, but with one side curved!( sorry-O level maths-1963!)This angle is 57.3 degrees and there are 1000 milliradians in 57.3 degrees and in a circle there are 6283.18 milliradians. Not a good number for using on a compass. Anyway, in Sweden they use 6300 mils, Russia, China and others-Iraq in 1991, use 6000 mils and NATO uses 6400 mils. The mil-not the milliradian, has a useful feature in that 1 mil covers (subtends) 1 metre at 1000 metres, 10 mils subtends 10 metres at 1 kilometre,50 metres at 5 kilometres and so on. This is used for fire control of mortars, guns etc.In fact the figure is really 1 mil subtends 1018 metres not 1000 metres -but who is counting? I believe that Germany came up with this system between WW1 and WW2 as a means of enabling their standing army of 100,000 to be expanded rapidly. (Treaty of Versailles, 1919, limited the size of their army)So Germany had lots of clubs and societies that could change into uniform and be effective soldiers quickly. I can find nothing on the web that corroborates what I have written here, but believe it to be correct. German optical equipment of this period, which I have seen, seems to be marked in 6400 mils. After WW2 NATO changed to the mil around 1965-66. Another useful feature is that the points of a compass fit in with mils as 200 or 400 mils per point depending if there are 16 or 32 points of a compass. - Submitted by Tony Borkowski