Faber Castell 1/38 Stadia 400g tachymeter slide rule 1959 Germany

This is a 1959 made wooden Faber Castell slide rule for land surveyors. So made to the needs of a special group of workers to aid with the calculation of stadia or tachymeter measuring over great distances, often aided by additional measuring equipment like the Theodolite. The slide rule is called the Tachymeter (aka stadia), model 1/38 (predecessor of the 111/38 in plastic). This one uses the 400 gon basis. It is signed beneath the slider as well as on the original black cardboard case. The instructions on the back of the slide rule are in German for the 400gon are used mostly in Europe (non English speaking countries). Everything is in overall good condition and complete with some signs of normal use and age only. it measures ca. 30 cm or ca. 12 inches. Check the attached video on how to work your vintage man tool : slide rule operation instructions!