A rare WWI mahogany cased part B trench forward spark wireless radio transmitter Lavington, London, circa 1915 The rectangular grey painted fabric covered two-tier box with top tier enclosing TREMBLER ADJUSTMENT knob, spark gap cleaner and applied Bakelite plaques inscribed W.T. SETS FORWARD SPARK, 20 WATT B. MkII, FRONT TRANSMITTER PART B, 65 METRES, No. 665 and W/T. FACTORY, W.D,SOHO. W over M.O.D. arrow marks, the inside of the lid with pasted label printed with INSTUCTIONS FOR USE, the bottom tier enclosing spark coil indistinctly inscribed ..NGTON, No. 249, connection block labelled PART A, Morse contact points and a small box of spare parts, the exterior with leather carrying strap over clasps and fold-down Morse key thumb-piece to front and antennae connection posts to right hand side, 24cm (9.5ins) high. The current lot is a relatively scarce early variant of transmitter used for military communication (via Morse code) in the trenches during the First World War which was subsequently superseded by more powerful (30 and 50 watt) sets.