A First World War French Aircraft Altimeter by L.Hatot, the 9cm blackened revolving outer dial with fluorescent numbers from 0 to 4, the silvered inner dial numbered 38 to 80, enclosing AVIATION MILITAIRE, L.HATOT FABRT. Besancon, BAROMETRE ALTIMETRE, COMPENSE, with blued steel needle under bevelled glass in an aluminium drum case with brass winding knob and numbered 11458, the stitched leather outer case with four suspender rings for attaching to the cockpit, the reverse inscribed in ink Walter C.Fentig, 1st Lt. Air Service, A.E.F., 11cm diameter.
Footnote:- Used by the American Expeditionary Forces in the First World War