Abstract: An electronic manometer for measuring pressure differentials between first and second outlets of a U tube supporting a column of mercury. The U tube includes for each arm a coaxial feedline which is terminated by the column of mercury. The coaxial feedlines are connected to first and second oscillators where they serve as the frequency determining circuit element of the oscillators. The wavelength of each oscillator frequency of oscillation is directly proportional to the height of the mercury column. A frequency counter and computer are connected to measure this wavelength, and apply any necessary corrective factors to the measurement.