The most fascinating thing at Aunt Em's house was the water pump in the kitchen. This pump was connected by a pipe to an underground cistern where rainwater from the roof would collect This type of pump is called a "lift pump" because the water is lifted up out of the reservoir from above. Such pumps were widely used back in the seventeenth century, and it was commonly believed that the water was sucked up by the vacuum created by the pump The accepted scientific explanation was that "nature abhors a vacuum."
Evangelista Torricelli, a contemporary of Galileo, wondered why water could not be pumped up more than about 33 feet; was this the limit of nature's abhorrence? Torricelli suspected that perhaps the water was being forced up through the pipe by the pressure of the air rather than being sucked up by the vacuum. Because a 33 foot column of water was a rather cumbersome laboratory tool. he chose to use a heavier liquid such as mercury; this allowed him to use a pipe or tube of only about 30 inches. He used a glass tube one meter (39 inches) long that was closed at one end; he filled it with mercury, put his finger over the open end, and inverted the tube into a cup of mercury. When he removed his finger, some of the mercury drained into the cup, but most of it stayed in the tube. In fact, the mercury level in the tube remained at about 30 inches. The space above the mercury was almost a perfect vacuum. Torricelli had just invented the first barometer. So, was it the vacuum holding the mercury up in the tube or was it the outside air pressure? How was he to prove it was the air pressure?
Torricelli proceeded to devise a very ingenious experiment; he would take his barometer to the top of a mountain, and if the mercury level remained the same, then it was the vacuum, if the level dropped then it was due to the reduced air pressure. Well, the result is history, the mercury level dropped several inches, and subsequently Torricelli sarcastically announced to the scientific world that evidently nature abhors a vacuum less at the top of a mountain. Torricelli had proved his point and before long his barometer and its principle were accepted by other scientists. His discovery resulted in the eventual development of the steam engine which signaled the beginning of the industrial revolution. Today his instrument is used in meteorological forecasting and in the altimeters used in airplanes.
God told Job the secret of the barometer thousands of years before Torricelli, but it took an Italian scientist in 1643 to convince a doubting world that God's word is correct. Even today, when we "suck" water through a straw, perhaps we need to be reminded that God made "a weight for the wind."
