The Architonnerre (Architronito) was a steam-powered cannon, a description of which is found in the papers of

Leonardo da Vinci Leonardo di ser Piero da Vinci (15 April 14522 May 1519) was an Italian polymath of the High Renaissance who was active as a painter, draughtsman, engineer, scientist, theorist, sculptor, and architect. While his fame initially rested on ...

dating to the late 15th century, although he attributes its invention to

Archimedes Archimedes of Syracuse (;; ) was a Greek mathematician, physicist, engineer, astronomer, and inventor from the ancient city of Syracuse in Sicily. Although few details of his life are known, he is regarded as one of the leading scientis ...

in the 3rd century BC. Leonardo's description was hidden amongst his papers until it was rediscovered by

Étienne-Jean Delécluze Etienne-Jean Delécluze () (26 February 1781 – 12 July 1863) was a French painter and critic. From 1797 on, he was a pupil of Jacques-Louis David, as he describes in his biography of David. As one of his favorite pupils, he was invited t ...

of the

French Institute The (; ) is a French learned society, grouping five , including the Académie Française. It was established in 1795 at the direction of the National Convention. Located on the Quai de Conti in the 6th arrondissement of Paris, the institute ...

in 1838 and published in the magazine ''

L'Artiste ''L’Artiste'' was a weekly illustrated review published in Paris from 1831 to 1904, supplying "the richest single source of contemporary commentary on artists, exhibitions and trends from the Romantic era to the end of the nineteenth century." ...

'' in 1841, well after the modern high pressure

steam engine A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be ...

had been independently invented.

Description of operation

The following is the most likely means of operation from the description given. A conventional muzzle-loading

cannon A cannon is a large- caliber gun classified as a type of artillery, which usually launches a projectile using explosive chemical propellant. Gunpowder ("black powder") was the primary propellant before the invention of smokeless powder ...

would have a strong metal tube connecting the vented end, where the fuse would normally be placed, to a copper

boiler A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central ...

, terminating below the water level inside but describing an inverted U above it in the manner of a

syphon A siphon (from grc, σίφων, síphōn, "pipe, tube", also spelled nonetymologically syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in a ...

. 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 description

Account from the ''Nelson Examiner and New Zealand Chronicle'', 1842:

The Steam-Engine. – M. Delecluze has lately made a discovery among the manuscripts of Leonardo da Vinci, carrying back a knowledge of the steam-engine to at least as far back as the 15th century. 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. – The ''Architonnerre'' is a machine of fine copper, which throws balls with a loud report and great force. It is used in the following manner : – One third of this instrument contains a large quantity of charcoal fire. When the water is well heated, a screw at the top of the vessel which contains the water must be made quite tight. 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. This machine will carry a ball of a talent in weight." 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. A Roman talent was , although the amount varied across the ancient world by a few kilograms.

References

Quoted in {{authority control 15th century in science Leonardo da Vinci projects Artillery Italian inventions Steam power Cannon Weapon history

Description of operation

Leonardo's own description

See also

References