WW1 French Huet Artillery Range finder Compass, l know nothing about this item, parents getting older and keep clearing out stuff IE giving it to me, compass works, spirit level working, you can look through one part and see millimeres though can't see all the way through if that makes sense.

This is what I could find out online

This is a rare and unusual French military rangefinder and compass instrument, made by Huet of Paris c.1911-1920, and used during WW1 by French artillery units. This type of instrument was known as a Sitomètre (or sitogoniomètre) in French and Sitometer in Swiss German. The name comes from the French expression for elevation angle which is called angle de site while the azimuth angle is called angle de gisement. The angle of elevation of the target can be viewed through a small window when the case is held vertically, while the bearing from magnetic north (Decigrade scale) can be read through a separate window when the case is held horizontally.

Any questions please feel free to ask.