Magnetic reactions produced by a copper disk rotating between the poles of a magnet [abstract]

For measuring the amount of work produced by a human being, a “bicycle ergometer” is in use at the Nutrition Laboratory of the Carnegie Institution of Washington. A description is given of this instrument, and of its calibration inside of a large calorimeter. It is found that the amount of heat expended per revolution of the pedals, instead of increasing proportionately with the speed, reaches a maximum and then decreases. Over the limited range of speeds commonly employed, the heat per revolution can be taken as practically a constant quantity. The present investigation was undertaken primarily in order to investigate this peculiarity in the calibrations.