British technical equipment. Comprising a Sight Mark IV clinometer, dated 1943. A slide rule marked Shell M101 Gun 155 mm. A slide rule in black leather case. A small metal instrument, marked Tool Steel Hardened Ground Edge British Buttner. A small metal ruler, dated 1935 with its broad arrow. A flight instrument, marked Short's Gas Leak Indicator. A metal battery, complete with moving parts. Markings Condenser Type 428 Ref N 10C/10920 AM under crown 1-5 MFD 4000 Volts DC Working. Some wear and patina to parts. Condition II+. British technical equipment group. Including one clinometer Sight Mk IV dated 1943, one slide rule marked Shell M101 Gun 155 mm, one slide rule in black leather case, one small metal instrument marked Tool Steel Hardened Ground Edge British Buttner, one small metal ruler dated 1935 with broad arrow mark, one flight instrument marked Short's Gas Leak Indicator, and one complete metal battery with moving parts functional, marked Condenser Type 428 Ref No 10C/10920 AM under crown 1-5 MFD 4000 Volts DC Working. Showing some wear and patina. Condition II+.