Editing Barometer (section)

===Sympiesometer===
[[Image:Sympiesometer from A R Easton, Aberdeen.jpg|thumb|right|upright=0.5|Sympiesometer inscribed at bottom ''Improved sympiesometer'' and at top ''[[A R Easton]], 53 Marischal Street, Aberdeen.'' Owned by descendants of the [[Aberdeen]] shipbuilding [[Hall]] family.]]

A [[sympiesometer]] is a compact and lightweight barometer that was widely used on ships in the early 19th century.  The sensitivity of this barometer was also used to measure altitude.<ref name=Stanton>{{cite book|last1=Stanton|first1=William|title=The Great United States Exploring Expedition|date=1975|publisher=University of California Press|location=Berkeley|isbn=0520025571|page=[https://archive.org/details/greatunitedstate00will/page/126 126]|url-access=registration|url=https://archive.org/details/greatunitedstate00will/page/126}}</ref>

Sympiesometers have two parts. One is a traditional [[mercury thermometer]] that is needed to calculate the expansion or contraction of the fluid in the barometer. The other is the barometer, consisting of a J-shaped tube open at the lower end and closed at the top, with small reservoirs at both ends of the tube.

In 1778, Blondeau developed an iron tube barometer using narrow-bore musket barrels. This design resulted in a durable and polished instrument that resisted mercury corrosion and minimized breakage from the ship's movement.<ref name=":3" />