The attached photo first appeared in a 1918 issue of GREAT WAR MAGAZINE and pictures the Brandt Grenade-Thrower.
Designed in 1916 by the Frenchman Edgar William Brandt (1880 - 1960), the Brandt Grenade-Thrower was a commonly used piece of trench artillery that was most often found in the French sectors. It was easily recognized for it's highly pronounced barrel that narrowed at the muzzle. An air operated mortar of 75mm caliber, this piece of military hardware was one of several compressed air projectors deployed by the French Army.