The sundial plate is by Louis Marie Arthur Chevalier (1830-1874).
This sundial is inscribed ‘CONSTRUIT PAR ARTHUR CHEVALIER PALAIS’. It is based on a noonday cannon commissioned by the Sun King, Louis XIV, for the gardens of Versaille. This miniature bronze cannon is set off at noon by the sun’s rays, which are magnified through a lens.
This is an extremely rare type of sundial, having been primed with gunpowder, is designed to fire at midday as a result of the magnifying glass focusing on the sun’s rays of the fuse.