Indirect fire

The development of electrical communication immensely simplified reporting, and enabled many widely dispersed firers to concentrate their fire on one target.

[5] For several centuries Coehorn mortars were fired indirectly because their fixed elevation meant range was determined by the amount of propelling powder.

It is also reasonable conjecture that if these mortars were used from inside fortifications their targets may have been invisible to them and therefore met the definition of indirect fire.

that Niccolò Tartaglia's invention of the gunner's quadrant (see clinometer) in the 16th century introduced indirect fire guns because it enabled gunlaying by instrument instead of line of sight.

[6] This instrument was basically a carpenter's set square with a graduated arc and plumb-bob placed in the muzzle to measure an elevation.

There are suggestions,[7] based on an account in Livre de Canonerie published in 1561 and reproduced in Revue d'Artillerie of March 1908, that indirect fire was used by the Burgundians in the 16th century.

[citation needed] The earliest example of indirect fire adjusted by an observer seems to be during the defence of Hougoumont in the Battle of Waterloo where a battery of the Royal Horse Artillery fired an indirect Shrapnel barrage against advancing French troops using corrections given by the commander of an adjacent battery with a direct line of sight.

In 1882 a Russian, Lt Col K. G. Guk, published Field Artillery Fire from Covered Positions that described a better method of indirect laying (instead of aiming points in line with the target).

This was a gun-mounted rotatable open sight, mounted in alignment with the bore, and able to measure large angles from it.

[10] Although both sides demonstrated early on in the conflict that they could use the technique effectively, in many subsequent battles, British commanders nonetheless ordered artillery to be "less timid" and to move forward to address troops' concerns about their guns abandoning them.

The early goniometric devices suffered from the problem that the layer (gun aimer) had to move around to look through the sight.

The British adopted the name "Dial Sight" for this instrument; the US used "Panoramic Telescope"; the Russia used "Goertz panorama".

These could be separate instruments placed on a surface parallel to the axis of the bore or physically integrated into some form of sight mount.

Initially, the angle between the aiming point and target area is deduced, or estimated, and set on the azimuth sight.

Originally "zero", meaning 6400 mils, 360 degrees or their equivalent, was set at whatever the direction the oriented gun was pointed.