Hence followed the astatic multiplying galvanometer.
His most valuable contributions to science consist in the suggestion of the astatic combination of two needles for galvanometers, and in the invention of the so-called thermomultiplier used by him and M.
Attention was first directed to the possibility of rendering ordinary pendulums more truly astatic by Professor Thomas Gray, who suggested methods by which this might be accomplished.
In the Wiechert astatic pendulum seismometer the stationary mass is also cheese-shaped, but it is supported by a conical extension from its base, which balances it on the floor of its case.
It has been already mentioned that Schweigger invented in 1820 the " multiplier," and Nobili in 1825 the astatic galvanometer.