Marquis de Dion invented submarine according to the magazine Mitteilungen aus dem Gebiete des Seewesens dated 1904 no. 11

An item reported that the model of a submarine designed by Marquis de Dion was to be tested by the French navy. The size was reduced to 1:10. Fish shaped hull, a displacement of 100 tons and a crew of 5 men. The designer believed that his concept contained new ideas.(1)

Note
1. Albert de Dion (9 March 1856 Carquefou, France-19 August 1946 Paris, France), French industrialist.