Editing Barograph (section)

==Development==
[[Image:Barograph 03.jpg|thumb|right|A barograph fitted with five aneroid capsules stacked in series, to amplify the amount of movement]]
[[Alexander Cumming]], a watchmaker and mechanic, has a claim to having made the first effective recording barograph in the 1760s using an [[Manometer#Aneroid|aneroid]] cell.<ref name="ODNB">Gloria Clifton (2004), [http://www.oxforddnb.com/templates/article.jsp?articleid=6893&back=,6895 "Cumming, Alexander (1731/2–1814)"] {{webarchive|url=https://web.archive.org/web/20140322153936/http://www.oxforddnb.com/templates/article.jsp?articleid=6893&back=,6895 |date=2014-03-22 }}, ''[[Oxford Dictionary of National Biography]]'', Oxford University Press. (Subscription or UK public library membership required)</ref> Cumming created a series of barometrical clocks, including one for King [[George III]]. However, this type of design fell out of favour. Since the amount of movement that can be generated by a single aneroid is minuscule, up to seven aneroids (so called Vidie-cans) are often stacked "in series" to amplify their motion. This type of barograph was invented in 1844 by the Frenchman [[Lucien Vidi]] (1805–1866).<ref name=r1>{{cite book|author1=Louis Figuier|author2=Émile Gautier|title=L'Année scientifique et industrielle|url=https://archive.org/details/bub_gb_Cus0AAAAMAAJ|year=1867|publisher=L. Hachette et cie.|pages=[https://archive.org/details/bub_gb_Cus0AAAAMAAJ/page/n495 485]–486}}</ref>

In such barographs one or more [[Manometer#Aneroid|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. A scribe records on smoked foil while a pen records on paper using ink, held in a nib. The recording material is mounted on a [[cylinder (geometry)|cylindrical]] drum which is rotated slowly by [[clockwork]]. Commonly, the drum makes one revolution per day, per week, or per month and the rotation rate can often be selected by the user.

Various other types of barograph have also been invented.  [[Karl Kreil]] described a machine in 1843 based on a [[Siphon#Siphon barometer|syphon barometer]], where a pencil marked a chart at uniform intervals.<ref>{{Cite book|title=The History of the Barometer|url=https://archive.org/details/historyofbaromet00midd|url-access=registration|last=Middleton|first=WEK|publisher=Johns Hopkins|year=1964|location=Baltimore}}</ref>  [[Francis Ronalds]], the Honorary Director of the [[King's Observatory|Kew Observatory]], created the first successful barograph utilising [[Photography#Science and forensics|photography]] in 1845.<ref>{{Cite book|title=Sir Francis Ronalds: Father of the Electric Telegraph|last=Ronalds|first=B.F.|publisher=Imperial College Press|year=2016|isbn=978-1-78326-917-4|location=London}}</ref>  The changing height of the mercury in the barometer was recorded on a continuously moving photosensitive surface.<ref>{{Cite journal|last=Ronalds|first=B.F.|date=2016|title=The Beginnings of Continuous Scientific Recording using Photography: Sir Francis Ronalds' Contribution|url=http://www.eshph.org/blog/2016/04/19/1642/|journal=European Society for the History of Photography|access-date=2 June 2016}}</ref>  By 1847, a sophisticated temperature-compensation mechanism was also employed.  Ronalds’ barograph was utilised by the UK [[Met Office|Meteorological Office]] for many years to assist in [[weather forecasting]] and the machines were supplied to numerous observatories around the world.