Abstract
A new oil-filled vacuum manometer is described, which has considerable advantages over conventional vacuum gauges. It is provided with a simple de-aeration chamber, in which the oil can be completely freed from dissolved gases within a few minutes, thus avoiding subsequent errors from the release of dissolved gases.
The new gauge compares favourably with a McLeod gauge of range 0-10 mmHg: it is much simpler and cheaper to construct; it is of similar accuracy (except at pressures below about 1 mmHg) and of much wider range; it gives readings continuously; and its accuracy is unimpaired by the presence of condensable vapour.