Barograph
Overview
 
A barograph is a recording aneroid barometer. It produces a paper or foil chart called a barogram that records the barometric pressure over time.

Barographs use one or more aneroid cells acting through a gear or lever train to drive a recording arm that has at its extreme end either a scribe or a pen. A scribe records on smoked foil while a pen records on paper using ink, held in a knib.
 
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