Jupiter, Neptune and a Titan

We are grateful to Maria Teresa Caracciolo Arizzoli for kindly confirming the attribution in a communication dated 18 November 2006. She plans to include the drawing in a forthcoming article in Cahiers de l'Histoire de l'Art that will be a supplement to her 1992 monograph on Cades (M.T. Caracciolo, Giuseppe Cades, 1750-1799: et la Rome de son temps, Paris, 1992).