Rare Simmance-Abady Flicker Photometer in Very Good Working Condition. England, 1902

This amazing device is a Simmance-Abady mechanical flicker photometer, made in England in 1902 by Nadel Brothers & Co. It is a rare and beautiful instrument composed of a mahogany wooden box and a black-enameled iron mechanism. Inside the box rests the mechanical motor that gives life to the photometer. This device is very well preserved and has survived to our days in great condition though being more than one hundred years old. It works perfectly and is worthy of a great museum in fact, a similar photometer is part of the London Science Museum collection. This photometer is one of the first models ever manufactured. It was made by Nadel Brothers & Co., an electrical measurement instrument maker from London. The company was founded in the 1880s and disappeared in 1909. A flicker photometer is a scientific surveying device that compares the brightness of two light sources. They are based upon the principle that flicker flicker between two alternating lights of different color is at a minimum when the brightness of the two is equal. These photometers use the lights sources to be compared to illuminate alternately a single field of view - disappearance of flicker signifies equality of luminance. This particular photometer mounts a brass eyepiece, a semicircular scale and two glasses to lead the light sources. Inside the wooden box there is also a paper roll and different pieces and gears. The scale bears an engraved inscription that reads: SIMMANCE PATENT FLICKER PHOTOMETER. On the other hand, screwed to the box there is an oval metal plate with the inscription PART OF A 19898. The box is really beautiful, with fine tongue-and-groove joints and protected by a nice satin transparent finish. Quite rare and in amazing condition, this flicker photometer will shine as part of the best collection of scientific antiques. Measurements: Width: 5.1 in / 13 cm. Height: 7.8 in / 20 cm.