Determining Mean Effective Pressure from indicator diagrams
Notes: "The Mechanical Specialties planimeter was very special purpose. For one thing, it never left its box. The indicator diagram would be placed in the box under the retaining clips, and the planimeter would trace around it. One end of the tracing arm rides in the groove of a rail inside the box. The reading is taken from the sharp-edged sliding wheel, which slides along a graduated bar. Complete instructions, which are quite brief, are in the lid of the box."