Theory and description are given of sensitive capacity-type seismometers having small size, eddy-current damping, and an undamped period of 0.23 second. The voltage output is taken to the grid of a cathode-follower tube within the instrument and is thereafter amplified. The suspension of the mass (by torsion wire) is of identical character in both vertical- and horizontal-component instruments. Records are given of tremors observed with a magnification of 7,000.