General area measurement and determining the mean height of indicator diagrams.
Notes: "This planimeter is a German-made, very close copy of the Amsler Type 6. Where Amsler's serial number would be, this one is stamped ""GERMANY"". Next to that there is a serial number, 5869. There is no maker's name or mark. What appears to be an inventory number has been lightly engraved with a hand-held engraver into the underside of the pole arm: UW65MT203."