Architonnerre
The Architonnerre (Architronito[1]) was a steam-powered cannon, a description of which is found in the papers of Leonardo da Vinci dating to the late 15th century, although he attributes its invention to Archimedes in the 3rd century BC.[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][7] Description of operationThe following is the most likely means of operation from the description given.[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. A fire of charcoal would heat the vented end of the cannon and the boiler so that the metal of the cannon's end would become red hot and the boiler would boil vigorously. Steam would be allowed to escape from the boiler through an opening with a screwed thread so there would be no buildup of pressure. To fire the cannon a cap would be screwed tightly into the boiler opening, triggering an immediate buildup of steam pressure in the boiler. This would force the boiling water along the syphon tube into the cannon's base. Here it would come in contact with the red hot cannon walls and flash into steam, the pressure of the sudden release of steam forcing the cannonball out of the muzzle. Leonardo's own descriptionAccount from the Nelson Examiner and New Zealand Chronicle, 1842:[2]
The weight of the cannonball is described as one talent. A Roman talent was 32.3 kilograms (71 lb), although the amount varied across the ancient world by a few kilograms.[9] See alsoReferences
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