26 HIGH SENSITIVITY HIGH SPEED RECORDERS OF MAGNITUDES OF TEMPERATURE, HUMIDITY, FREQUENCY, SPEED, PRESSURE, CONDUCTIVITY, ION CONCENTRATION, RATE OF FLOW OF FLUIDS, ELECTRIC CURRENT, ELECTRICAL IMPEDANCE, ELECTRICAL POTENTIALS AND VOLTAGES, [ TURBIDITY, PHOTO ELECTRIC EFFECTS, ] AND COMPOSITION OF MIXTURES; RECORDERS CONTROLLED BY A MEMBER DEFLECTING IN RESPONSE TO THE MAGNITUDE OR CHANGES IN MAGNITUDE TO BE RECORDED; HIGH SENSITIVITY ELECTRIC CONTROLLERS AND REGULATORS OF TEMPERATURE, HUMIDITY, CONDUCTIVITY OF FLUIDS, ION CONCENTRATION, COMBUSTION, RATE OF FLOW AND PRESSURE OF FLUIDS, COMPOSITION OF MIXTURES, ELECTRIC CIRCUITS, ELECTRIC CURRENTS, ELECTRO-MOTIVE FORCES,AND ELECTRICAL IMPEDANCES; FOR ELECTRIC CONTROLLERS OF STEAM GENERATOR FURNACES AND FOR ELECTRIC CONTROLLERS OF STEAM GENERATION; FOR ELECTRIC CONTROLLERS, REGULATORS, AND GOVERNORS OF SPEED AND FREQUENCY; AND FOR ELECTRIC CONTROLLERS AND REGULATORS OF FREQUENCY OF ELECTRIC AND MECHANICAL VIBRATION