Physics Pressure in a Barometer Problem?

David: Let's think. The closed end of the tube has a partial vacuum. The open end is open to the atmosphere. As the atmospheric pressure varies according to the column of air above it, say a high pressure, or low pressure area above the tube, the level of the mercury will vary. However, the mercury pressure at the bottom will be constant. The only thing equal to this measurement would be the absolute pressure as I see it. Pressure is weight and it remains constant.