was, however, useless for moving large masses or for working against the current. “Jouffroy saw the defects caused by the fact that the rapidity of the boat’s motion prevented the hinged flaps from reopening after the forward stroke, especially when the pyroscaphe was moving upstream or against the tide. Hence the engine only acted at intervals instead of keeping up a sustained movement. But Jouffroy substituted paddle-wheels for the hinged flaps (_volets à charnière_) and devised a new machine in which the action of the steam was made continuous by means of two bronze cylinders, the top placed lengthwise with the run of the ship, making with the horizon an angle of about 50 degrees. The bottoms of the cylinders were encased in a metal box containing a sliding tile which opened and shut, alternately giving a passage to the steam and the intake of water in each cylinder. [12] The name is spelt “Perrier” by some writers. [Illustration: THE MARQUIS DE JOUFFROY’S STEAMBOAT. 1783.] “By July 1, 1783, Jouffroy had constructed a second boat which was launched at Lyons. Its dimensions were considerable, the length attaining 46 m. and the breadth 4 m. 50 c. The wheels were 4 m. diameter, the paddles 1 m. 95 c., dipping 65 c. The draught of water of the vessel was 95 c. The total weight was 327 milliers, of which 27 were for the vessel and 300 for the freight. This enormous vessel voyaged against the tide of the Saône from Lyons to L’île Barbe in the presence of the Commission de Savants and thousands of spectators, as officially recorded in the archives of the Municipality of Lyons.” Arago says this vessel continued to navigate the Saône for sixteen months.[13] [13] Paper read by the Marquis de Bausset-Roquefort before the Lyons Literary Society in 1864, and preserved at the Mazarin Library (Academy of Sciences), Paris.