| Answer | Crossword Clue |
|---|---|
| planimeters | PLANIMETER, an instrument for measuring the area of plane figures |
| planimeter | an instrument for measuring the area of plane figures |
| planimeter | An instrument for mechanically measuring the area of a plane figure |
| planimeters | An instrument for mechanically measuring the area of a plane figure |
| polarimeters | An instrument for measuring the polarization of light, and esp. (in chemical analysis) for determining the effect of a substance in rotating the plane of polarization of light |
| polarimeter | An instrument for measuring the polarization of light, and esp. (in chemical analysis) for determining the effect of a substance in rotating the plane of polarization of light |
