Editing Barometer (section)

=== Baliani's siphon experiment ===
[[File:NSRW Siphon diagram.jpg|thumb|176x176px|Siphon]]
On 27 July 1630, [[Giovanni Battista Baliani]] wrote a letter to [[Galileo Galilei]] explaining an experiment he had made in which a [[siphon]], led over a hill about 21 m high, failed to work. When the end of the siphon was opened in a reservoir, the water level in that limb would sink to about 10 m above the reservoir.<ref name=":0">{{Cite book |last=Middleton |first=W. E. Knowles. |url=http://archive.org/details/historyofbaromet00midd |title=The history of the barometer |date=1964 |publisher=Johns Hopkins Press |pages=9}}</ref> Galileo responded with an explanation of the phenomenon: he proposed that it was the power of a vacuum that held the water up, and at a certain height the amount of water simply became too much and the force could not hold any more, like a cord that can support only so much weight.<ref name=":0" /><ref name="Shea2003">{{cite book|author=Shea, William R. |title=Designing Experiments & Games of Chance: The Unconventional Science of Blaise Pascal|url=https://books.google.com/books?id=-x6B1Q5UoE4C&pg=PA21|access-date=10 October 2012|year=2003|publisher=Science History Publications|isbn=978-0-88135-376-1|pages=21–}}</ref><ref name="History of the Barometer">{{cite web|url=http://www.strange-loops.com/scibarometer.html |title=History of the Barometer |publisher=Strange-loops.com |date=2002-01-21 |access-date=2010-02-04| archive-url= https://web.archive.org/web/20100106074525/http://www.strange-loops.com/scibarometer.html| archive-date= 6 January 2010| url-status= live}}</ref> This was a restatement of the theory of ''[[Horror vacui (physics)|horror vacui]]'' ("nature abhors a vacuum"), which dates to [[Aristotle]], and which Galileo restated as ''resistenza del vacuo''.