Architonnerre

[2][3][4] Leonardo's description was hidden amongst his papers until it was rediscovered by Étienne-Jean Delécluze of the French Institute in 1838 and published in the magazine L'Artiste in 1841, well after the modern high pressure steam engine had been independently invented.

[2][5][6] [8] A conventional muzzle-loading cannon would have a strong metal tube connecting the vented end, where the fuse would normally be placed, to a copper boiler, terminating below the water level inside but describing an inverted U above it in the manner of a syphon.

He has published in the Artiste a notice on the life of Leonardo da Vinci, to which he adds a fac-simile of a page from one of his manuscripts, and on which are five sketches with the pen, representing the details of the apparatus of a steam-gun, with an explanatory note upon what he designates under the name of the " Architonnerre," and of which note the following is a translation : – " Invention of Archimedes.

On closing the screw above, all the water will escape below, will descend into the heated portion of the instrument, and be immediately converted into a vapour so abundant and powerful, that it is wonderful to see its fury and hear the noise it produces.

It is worthy of remark that Leonardo da Vinci – far from claiming the merit of this invention for himself or the men of his time – attributes it to Archimedes.The weight of the cannonball is described as one talent.