in March 1869 as being £8,000 and was awarded to the local firm of James Todd, after complaints that local builders had not had the opportunity to reply to tender as it had not been advertised locally. The foundation stone was ceremonially laid by Admiral Collinson's sister on 9 June 1869. Building works were completed in 1870, and the lighthouse entered service in January the following year. After completing this project Douglass and Norris moved on to the building of Hartland Point Lighthouse in Devon. Electricity Carbon arc lights for lighthouses were pioneered by Professor Frederick Hale Holmes, with experiments carried out in 1857–60 at Blackwall and at South Foreland Lighthouse (as described in a lecture by Michael Faraday at the Royal Institution). An initial installation at Dungeness Lighthouse in 1862 had proved problematic, however, with frequent failures of the lamps and machinery; so Trinity House carried out an extensive testing and selection process over five years (including comparisons with oil lights and examination of equipment in Britain and France) before finalising its plans for a complete purpose-built electric installation at Souter. The carbon arc lamp at Souter was placed within a lens array consisting of a third-order fixed catadioptric optic surrounded by a revolving assembly of eight vertical condensing-prisms which produced one bright flash every thirty seconds. Its 800,000 candle power light could be seen for up to 26 miles. The optics were designed and built by James Chance in 1870. In addition to the main light a red/white sector light shone from a window in the tower below the lantern, to highlight hazards to the south in Sunderland Bay (namely Hendon Rock and the White Stones); it was powered using light diverted (through a set of mirrors and lenses) from the landward side of the main arc lamp. Electricity for the light was provided by two of Holmes' own magneto electric generators for which he took out a series of patents during those years. In normal operation only one generator was used, but in conditions of poor visibility both were connected to the lamp to provide a brighter light. The generators were driven by one of a pair of J. Whitworth & co. 5 nhp 'Allen' condensing steam engines. (Prior to being installed at Souter, the engines and generators were exhibited by Trinity House at the Paris Exposition of 1867.) The engines were worked alternately: one week on,