tachometers, speed meters, accelerometers, pressure meters, photometers, luminoflux meters, illuminometers, refractometers, hygrometers, calorimeters, flowmeters, lelvel gauges,level sensors, denismeters, concentration meters, gravimeters, viscosimeters, vibration gauges, dynamometers, ships, logs, gauge comparators,interferometers, angle dividing machines, calibration checking instruments, clinometers, angle gauges, pressure automatic control machines and instruments, vacuum automatic control machines instruments, liquid level automatic control machines and instruments, fluid composition automatic control and instruments, automatic control amchines and instruments, program controlling machines and instruments, hydrophones, applied ultra-sonic echo sounders, applied ultra-sonic flaw detectors, magnetic object detectors, electronic computers, thermometers, planimeters, gas meters, water meters, level indicators, remote control and telemetering apparatus, distance measuring instruments, capacity measures, detectors, electrical circuit testers, oscillographs, recorders, indicators and other photographic, cinematographic, optical, weighing, measuring, signaling, checking apparatus and instruments