Why is mercury used in thermometers ?

Why mercury is used in barometer for measuring atmospheric pressure?

Volume of the bulb of a mercury thermometer at 0^(@)C is V_(@) and area of cross section of the capillary tube is A_(0) , coefficient of linear expansion of glass is alpha_(g) , and the cubical expansion of mercury is gamma_(m) . If the mercury fills the bulb at 0^(@)C , find the length of mercury column in thermometer at T^(@)C

Why is mercury taken in a barometer?

Mercury is used in thermometers because