9 photoelectric and photoresistant cells; scientific instruments; namely, actinometers, geodesic instruments; namely, goniometers, graphometers, surveyor's staff, surveyor's rod, levels, small shelves, tacheometers, theodolites, electric instruments; namely, accumulators, batteries, ammeters, amplifiers; photographic instruments; namely, cameras, lens, exposure meters; optical instruments; namely, optical lens, optometers, lens, magnifying glass, glasses, meniscus, microscopes, periscopes, prism, stereoscopes; weighing instruments; namely, bascules, scales, microbalances, assay balances; measuring instruments; namely, pressure meters, ergometers, hydrometers, hygrometers; signalling instruments; namely, kilometer markers, road signals, traffic lights