Noon day cannon sundial signed on the white marble base
Rousseau . Inv . fec .
The base is engraved with an hour scale and has a shaped brass gnomon. There a two quadrant supports for the limbs holding the lensholder and biconvex lens. The cannon is mounted on two supports and has a little cover over the lower end of the barrel.
In operation, when the sun reaches its highest point during day, the rays of light are focused by the lens on to the little hole of the charged cannon, setting it off with a loud report signaling midday.
Diameter 20 cm.
Very good original condition with nice old patina.