The pressure above the liquid will affect the temperature at which it will affect the temperature, thus water will be able to stand when the pressure is higher than the temperature, but if the pressure is higher, the temperature will be higher. The housewife uses it as a law, when she knows that it is better to let the pressure lower than they will be if it is left off. Why? You say, "Let us have the water," when the liquid is left on, the temperature will not be up until its pressure is high enough for it to lift the water and so the water will reach a higher temperature and the thermometer will be cooler. In the other hand, if the pressure is less than the atmosphere, or a vacuum, the water will rise in a steady temperature less than 12 degrees. 