A gravimeter designed specifically to monitor the 0S0 dilational mode of the earth is described. The gravimeter is a modified LaCoste design constructed of fused quartz, operated in a high vacuum, and incorporated into an electrostatic null-seeking servo. The gravimeter data are digitally Fourier analyzed after passage through a heterodyne tide filter. The observed spectral density of the noise at 20-minute periods is 10-7 g/cpm. The noise can be attributed to temperature and tilt fluctuations and is not actual vertical earth noise. The purpose of the experiment is to search for evidence of scalar gravitational field radiation which may drive the 0S0 mode.