Salmson aero engine, c 1910s.

The engines were made to licence by Dudbridge Iron Works Limited in Stroud, Gloucestershire, to the designs of the Paris-based French aero company, Salmson. The figure on the right is believed to be Arnold Levien, an aero engineer from Salmson. Dudbridge specialised in the manufacture of gas engines but increased aero engine production during World War One.