Notes: "This is a pantograph planimeter, which means there are two additional arms connecting the main arms and creating a parallelogram. There is a second tracing point on the smaller arms, which is used for measuring small areas with greater precision. In effect this provides an adjustable length tracing arm. The pole arm is also adjustable; the point that sticks in the drawing board to provide a pivot can be slid along the pole arm and a set screw tightened to hold it in place. The weight fits directly over that point. Lyth's recording mechanism is also unlike any other, using a large-diameter tracing wheel, and having a pivoting pointer resting in a lead screw provide the function of a multiplier wheel. "