The photograph depicts a sketch of the Stiger Vortex Rainmaking Canons promoted by Clement Wragge after investigations in Europe and America into the techniques of “cloud shooting” from these rainmaking cannons.
"Stiger Vortex": Correspondence, sketches and report re same for hail prevention and rainmaking experiments in Europe. Numerous pamphlets on the various types of guns available and modes of use. (Pamphlets are in French, German and Italian). 1901-1914.