William Tregarthen Douglass; use was made of construction equipment which had become available following completion of the new Eddystone lighthouse (which had also been designed by Douglass) the previous year. The stones were cut and dressed off site, to precise dimensions, before being conveyed to the rock by steamer and then individually winched ashore. It took until 1886 for the time-consuming work of integrating the new stonework with the old to be completed, up to the height of the existing structure. Thereafter things moved more swiftly and the tower as a whole was finished in 1887. New optical and other equipment Douglass topped his rebuilt tower with a double-height lantern storey, designed to contain a 'biform' optical system designed and built by Chance Brothers (consisting of two identical lamps and lens arrays, one mounted above the other). Each tier consisted of an eight-wick paraffin burner set within a revolving array of extra large hyperradiant Fresnel lenses (consisting, on each level, of five pairs of lens panels, displaying two white flashes every minute). In clear weather the lower tier alone was used, with its lamp on half power; in limited visibility (as judged by the clarity of the light visible from St Agnes's Lighthouse, away) both tiers were used with the lamps at full power. The new improved light had a range of ; it was first lit on 25 October 1887. (The old dioptric apparatus was removed and later re-used: at Hurst Point and in the low light at Nash Point.) The heavy new optic was turned by a small air engine placed in the pedestal; compressed air was provided from a set of tanks, located in the room below along with a pair of Davey 'Safety' Engines, which drove the compressors. The compressed air could also be used, by day, to drive a small gallery-mounted winch for landing stores. As part of the new installation, the lighthouse was equipped with an explosive fog signal: in foggy weather the keepers regularly had to attach a guncotton charge together with a detonator to a jib-type apparatus on the lantern gallery; from inside the lantern they would then raise the jib and fire the charge electrically. The explosive signal remained in use until 1976. Later developments In 1902 a new clockwork mechanism was installed to turn the lenses; by this time the optic had been modified to float in an annular mercury