Later, in 1884, Professor Tyndall again conducted experiments for Trinity House at South Foreland, this time on the relative merits of gas lamps, oil lamps and electric lamps. For this purpose three temporary lighthouses were built, at the top of the cliff alongside the Upper Lighthouse, one powered by oil, one by gas and the third by electricity. Each provided space for different configurations of lamps or burners and optics to be tried. More than 6,000 observations were taken, from stations both on and offshore, and it was concluded that electric light was the most powerful under all conditions.