Barograph

Alexander Cumming, a watchmaker and mechanic, has a claim to having made the first effective recording barograph in the 1760s using an aneroid cell.

[2] In such barographs one or more aneroid cells act through a gear or lever train to drive a recording arm that has at its extreme end either a scribe or a pen.

Commonly, the drum makes one revolution per day, per week, or per month and the rotation rate can often be selected by the user.

Karl Kreil described a machine in 1843 based on a syphon barometer, where a pencil marked a chart at uniform intervals.

[3] Francis Ronalds, the Honorary Director of the Kew Observatory, created the first successful barograph utilising photography in 1845.

Ronalds’ barograph was utilised by the UK Meteorological Office for many years to assist in weather forecasting and the machines were supplied to numerous observatories around the world.

This evens out the motion of the ship so that a more stable reading can be obtained, this can be either oil damping of the mechanism or simple coiled spring feet on the base.

But, newer solid state, digital barographs eliminate this issue altogether, since they use no moving parts.

At this point the clockwork motor is wound and if necessary corrections can be made to increase or decrease the speed and new chart is attached.