Torricelli, Evangelista
Italian physicist who established the existence of atmospheric pressure and devised the mercury barometer in 1644.
In 1643 Torricelli filled a long glass tube, closed at one end, with mercury and inverted it in a dish of mercury. Atmospheric pressure supported a column of mercury about 76 cm/30 in long; the space above the mercury was a vacuum. Noticing that the height of the mercury column varied slightly from day to day, he came to the conclusion that this was a reflection of variations in atmospheric pressure.
In 1643 Torricelli filled a long glass tube, closed at one end, with mercury and inverted it in a dish of mercury. Atmospheric pressure supported a column of mercury about 76 cm/30 in long; the space above the mercury was a vacuum. Noticing that the height of the mercury column varied slightly from day to day, he came to the conclusion that this was a reflection of variations in atmospheric pressure.
© RM 2010. Helicon Publishing is division of RM.
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