Salmson biplane under construction, c 1917.

Photograph of an aeroplane being asembled, believed to have been taken at the Salmson factory outside Paris. The aircraft, probably a Salmson SAL-2 reconnaisance plane, is fitted with Z9 type engine. 3200 SAL-2s were built by Salmson and were flown by the French and American air forces during World War I.