• The countertorque increases in proportion to the excursion of the coil from its zero position.
• Large departures of the equipotential surface from sphericity will not affect the result.
• When there is a departure of the controlled pressure from the set value, the out-of-balance force moves a multiplying valve.
• The constant reported in this work may have a deviation of 1.1% from the absolute valve.
• These errors account for the deviation of the measurements from theory.
• Variations from this composition are found in commercial steels.
• h is the variation of the strip thickness from the required value.
• It appears that building such a large device is feasible and would require no major departures from present practice.