At first, the light had reflectors but changed to a dioptric (refracting) mechanism in 1838. The present lantern of 1856 is a 4.27 m (14 ft) wide chamfered octagon and the light is fixed, instead of revolving. The present revolving apparatus was put in place in 1873. It gives a group of five flashes, at first with an oil-lamp, but changed to electric in 1973.