How Do You Read A Spirit Level?
In the 1920s, master carpenter Henry Ziemann invented the spirit level that we use today. The level features a glass tube filled with a liquid spirit except for a bubble in the tube. The low viscosity of ethanol allows the quick movement of the bubble, and the glass tube has two lines the width of the bubble, drawn at the center of the tube. This will indicate if the level being measured is level or plumb. Place the flat edge of the level on the surface you wish to ascertain the horizontal. Ensure the glass tube with the bubble is laying parallel to the surface. Remove your grip from the level and watch where the bubble comes to a stop. The position of the bubble will indicate if the surface is sloping in one way or the other, or if it is level. If the bubble stops above the two lines, then the surface is sloping down one way and should be raised at one end. The surface should be tilted one way or the other until the bubble comes to a rest exactly between the two lines on the glass tub
