G958.)3rd RCH GERMAN ARMY ARTILLERY BAROMETER: an absolutely vital instrument for accurate artillery fire control. Comes in its original brown wooden box. 5" wide black-finished magnetic body, 3" deep. With burnished silver finished face, black numbers. Has glass and face is marked with German army eagle/swastika motif. Also marked with large letters 'MSS' which translates to millimeters of mercury. Serial numbered too '961' and marked as well with 'mb' for millibars. Maker's logo being stylized letter 'L'. 7x7" wooden case is hinged and has secure metal latch at front. Printed on the lid with 'Prazisions-Barometer'. Knowing the barometric pressure, along with air temperature and wind-direction played a vital role in accurate artillery fire, precise firing trajectories. Atmospheric pressure -- or air density -- dictates the amount of resistance to a projectile's flight. Applies to naval gunner too of course. EXC++++