Large Bell-shaped glass vessel (c. 1730-40), to demonstrate the Diving Bell. At the top is a brass tap to control air pressure, round the middle is a brass band with hooks from which are suspended 13 lead balls to regulate the weight [see Desaguliers, Experimental Philosophy, 1744, p.212, pl.XX, fig.2] Large Bell-shaped glass vessel (c. 1730-40) 1730-1740