 Hero was eventually refuted by experiments conducted by Evangelista Torricelli and Blaise Pascal. In effect, they created a barometer consisting of a tube partially submerged, upside down, in bowl of mercury. What keeps the mercury suspended in the tube? Is there an unnatural vacuum that causes the surrounding glass to pull the liquid up? Or is there no vacuum at all but rather some rarefied and invisible matter in the “empty space”? Pascal answered that there really was nothing holding up the mercury. The mercury rises and falls due to variations in the weight of the atmosphere. The mercury is being pushed up the tube, not pulled up by anything.