Why is only mercury used to measure atmospheric pressure?

Question

Why is only mercury used to measure atmospheric pressure?

Answer 1

It has to do with the mechanics of measuring atmospheric pressure. Mercury is a commonly available, dense liquid, and is thus ideal for use in barometers.  Briefly, if a less-dense liquid like water were used, the distance the water would rise would be much greater (about 13.5 times greater for water), making barometers, at least of the original design, much larger.  

Traditional barometers work by letting air pressure push mercury up a tube against gravity (the other end of the tube is sealed and has a vacuum).  The level of the mercury in the tube indicates where the mass of the mercury equals the air pressure.  Thus using a dense liquid like mercury, it is possible to make the tube itself much shorter.

Answer 2

Not only mercury can be used.

However, mercury has a strong advantage: its mass. Normal atmospheric pressure is around 760 mm of mercury. Using much lighter water, this means 10330 mm; a column 10 m in height is rather uncomfortable.

Answer 3

because of it's weght

Answer 4

Mercury is used because of it is fluid at the 'normal' range of temperatures and its  high density.  Any liquid can be used but the column of liquid in the barometer would have to be taller.

Thomas Jefferson took daily readingss of the air pressure, measured in feet and inches of water, during the meetings of Congress that led to the Declaration of Independence and announced them to the assembly.  Most of the delegates thought it an annoying waste  of time.  Others approved because it stopped the conservatives from talking, at least for a while.