marograph

plural marographs

1. An instrument for measuring the tides.

   Records of the variations in level of the ocean and the great lakes are kept by means of tidal registers, or marographs.

   2014, Russell Sturgis, Sturgis Illustrated Dictionary of Architecture and Building, page 14

   2 more examples

   We represent in the annexed engravings, for which we are indebted to La Nature, two new registering devices, one termed the marograph, designed for tide measurements, the other the fluviograph, intended for similar examination of river and canal levels.

   1875 October 9, Scientific American, page 227

   His work on microseisms including the installation of meteorological instruments in Ottawa and the marograph in Nova Scotia, was quite advanced for its time; I would say that no further advances were made in the subject until the 1940's.

   1989, The heavens above and the Earth below: A History of the Dominion Observatories, page 117