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
John Smeaton Wright brothers determined with wind tunnels that the Smeaton coefficient value of 0.005 was incorrect and should have been 0.0033. In modern analysis, the lift coefficient is normalised by the dynamic pressure instead of the Smeaton coefficient. Smeaton is important in the history, rediscovery of, and development of modern cement, identifying the compositional requirements needed to obtain "hydraulicity" in lime; work which led ultimately to the invention of Portland cement. Portland cement led to the re-emergence of concrete as a modern building material, largely due to Smeaton's influence. Recommended by the Royal Society, Smeaton designed the third Eddystone Lighthouse (1755–59).