Smeaton's Tower stood were becoming eroded. Each time a large wave hit, the lighthouse shook from side to side. Smeaton's Tower ceased operation in 1879 with the illumination of Douglass's Tower on an adjacent rock. In 1882 the upper part of Smeaton's Tower was dismantled and rebuilt as a memorial to Smeaton on a new base on Plymouth Hoe, replacing the triangular obelisk that had been built there by Trinity House as a navigation aid in the early 19th century. It was opened to the public by the Mayor of Plymouth on 24 September 1884. The foundation and stub of the old
Lighthouse that will set under water used by the Romans, and developed a technique of securing the granite blocks together using dovetail joints and marble dowels. The dovetailing feature served to improve the structural stability, although Smeaton also had to taper the thickness of the tower towards the top, for which he curved the tower inwards on a gentle gradient. This profile had the added advantage of allowing some of the energy of the waves to dissipate on impact with the walls. His lighthouse was the prototype for the modern lighthouse and influenced all subsequent engineers. One such influence was Robert