Vida Milovanovic discovers a fascinating connection between lighthouses and the Royal Society.
A volume displayed by a colleague during a recent Library ‘treasures’ tour caught my attention: A narrative of the building and a description of the construction of the Edystone lighthouse with stone (1791) by John Smeaton FRS. Featuring magnificent illustrations of the third lighthouse built upon the Eddystone Rocks, I found myself transported to the eighteenth century, staring at what was to become the standard blueprint for these magical structures fashioned to withstand the lashing of the turbulent sea.
Title page (RS.10561) and depiction of the south elevation (RS.10379), from Smeaton’s 1791 Narrative. The Royal Society’s copy was donated by the author himself on 20 January 1791.
Now celebrated as the first civil engineer, John Smeaton was initially known as a scientific instrument maker. He was elected to the Royal Society in 1753 ‘on account of his abilities in Mechanicks’, and his investigations on the power of water and wind led to his being awarded the Copley Medal in 1759.
In 1755 Mr Robert Harcourt Weston (owner of the lease of the Eddystone Rocks) wrote to Royal Society President George Parker, 2nd Earl of Macclesfield, seeking a suitable engineer to embark on rebuilding a lighthouse on the rocks. The Society recommended Smeaton for the job, creating a turning point in his career and immortalising him.
Portrait of Smeaton by Mather Brown ca. 1788 (RS.9720)
The previous two Eddystone lighthouses had both met with a disastrous end. The first, by Henry Winstanley, stood from 1698 until it was swept away in the Great Storm of 27 November 1703, killing its architect and five other men. The second, by John Rudyard, lasted from 1709 to 1755 before succumbing to a five-day inferno, caused by a spark from one of the candles illuminating it.
L: South elevation of the first lighthouse (RS.10377); R: South elevation and section of the second lighthouse (RS.10378)
An article in the Philosophical Transactions of the Royal Society records other details of the aftermath of the fire. 'An account of the case of a man who died of the effects of the fire at Eddy-stone Light-house' tells the story of Dr Edward Spry’s discovery of a piece of lead weighing over seven ounces in the stomach of Henry Hall, the 94-year-old lighthouse keeper on watch at the time, who died 12 days after the fire. Here’s the original manuscript on our Turning the Pages platform:
Enter Smeaton. Faced with a challenge his predecessors were unable to resolve, the design had to be structurally sound and non-flammable. He was granted complete freedom to pursue a radical redesign, and what followed was nothing short of genius.
For its shape, Smeaton drew inspiration from the English oak tree, observing its ability to withstand extreme winds owing to its heavy base and low centre of gravity. Mimicking the tree, Smeaton gave the base of his tower a curve which would act as a mechanism to disperse the energy of the waves:
He proposed that the tower should be fashioned entirely of stone, with the foundations and exterior to be composed of local Cornish granite and the interior featuring Portland limestone. The stone blocks were to be secured to each other using dovetail joints and marble dowels. To overcome the challenge of securing the stone blocks without mortar, which is useless in wet conditions, Smeaton pioneered ‘hydraulic lime’, a type of waterproof concrete which was able to set under water. In addition, he devised a crane to enable the lifting of building materials as the tower progressed.
Landing and hoisting the stones during the construction of Smeaton’s tower (RS.10382)
Construction took three years, starting in August 1756 with the cutting away of recesses in the rock designed to dovetail with the foundations of the tower, and ending on 16 October 1759, with the lighting of a chandelier comprising 24 large tallow candles. The lighthouse was 22m high, with a diameter at the base of 8m and at the top of 5m, and achieved worldwide fame for its innovative design.
Smeaton’s beacon stood for 120 years before cracks appeared in the rock in the late 1870s, and a new lighthouse was required. The top half of Smeaton’s tower was disassembled and re-erected on Plymouth Hoe to celebrate its builder. The remaining stump stands on the Eddystone Rock to this day, reminding us of the blueprint structure that resulted in standardisation of lighthouse building the world over, and as a monument to the first use of modern concrete in engineering.
