Determining Mean Effective Pressure from indicator diagrams
Notes: "This is a very unusual planimeter, but at it's core it works exactly the same as the Willis planimeter, from which is borrowed the sharp-edged wheel as its recording mechanism. Instead of having a rotating triangular ruler with scales, like the Willis, this uses paper scales sealed inside glass tubes. And further, the tracing wheel slides along the glass tube while an area is being measured! This is a very interesting and rare planimeter."
