Invariable pendulum no. 10 with agate plane no. 10, 1827, by Thomas Jones. In box with telescope, thermometers and accessories Kater's invariable pendulum, 1827 1827
Kater's convertible pendulum with three adjustable weights held in a fitted case and transported with a travel crate, 1817. Kater's convertible pendulum with two adjustable weights 1817