When the barometer is taken down into a coal mine the mercury level in the barometer rises. When we move down the earth's crust the temperature will increase, there is very less availability of wind so warmth is not able to distribute the temperature and moderate it. In the coal mine, the pressure is high as compared to normal pressure. A barometer is an instrument which is used to measure atmospheric pressure above or below the sea level . Mercury is an element used in a barometer to measure atmospheric pressure. The instrument was invented by an Italian scientist Evangelista Torricelli in the year 1643.