A seasonal mean sea-level indicator

Abstract

By means of oil capillaries the indicator attenuates the tidal rise and fall of the sea surface, as well as all fluctuations of higher frequencies. The time constant of the response is chosen so that the smaller, slower fluctuation of sea level is transmitted with very little change of amplitude and phase. There is no recorder. Visual reading of the oil level in a burette should be tabulated twice a week. Installation of the instrument is much easier and cheaper than a recording tide gauge.