The Leda sea serpent: Rev. John Macrae and Rev. David Twopeny at Loch Hourn and the Sound of Sleat, 1872

August 1872. The west coast of Scotland. Two ministers set out from Glenelg in a small cutter called the Leda, bound for Loch Hourn. Rev. John Macrae was the minister of Glenelg.

Rev. David Twopeny was the vicar of Stockbury, in Kent. Six people were aboard. What they saw over the next two days would later be called "the most detailed nineteenth-century report of sighting a purported sea serpent in the British Isles."

It began on 20 August. Kate Macrae saw something come up "looking like a small barrel", then five similar objects followed. She also saw "something like a rounded paddle, the breadth of two hands" moving through the water. Rev. John Macrae described a dark mass about 200 yards astern, while Gilbert Bogle called it "dark, slaty brown" and saw a small fin. More "black lumps" rose one after another, and Macrae wrote, "We did not doubt its being one living creature: it moved slowly across our wake, and disappeared."

The next day, near the mouth of the Sound of Sleat, it came back. The animal dived. It surfaced again, closer than before. The party could hear the "rushing sound of the breaking water."

Twopeny called the humps "half-rounds". A head came first, smaller and flatter than the body, the nose barely showing above the water. Behind it ran four or more lumps that "sometimes rose and sometimes sank altogether." Between three and seven were visible at once.

The ministers were precise on one point. "There was no appearance of undulation; when the lumps sank, other lumps did not rise in the interval between them." They judged it against passing trading schooners of around 70 feet. Their estimate was about 60 feet or more.

The Leda was not alone. Finlay McRae of Bundaloch was in his boat at the mouth of Loch Hourn on the 21st, about 150 yards away. Ferrymen at Kyle Rhea watched it pass "rapidly through on the evening of the 21st". Alexander Macmillan, a boat-builder at Dornie, saw it at the entrance to Loch Duich and put its length at "between sixty and eighty feet".

At Duisdale on Skye, a woman with a spyglass saw "eight seals in a row". People on the Isle of Eigg reported it too. Fishermen insisted it was "no seal or porpoise".

The ministers published their account in The Zoologist in 1873, with diagrams. Sceptics have long argued that sea serpent "coils" are often porpoises swimming in single file, and the Kyle Rhea ferrymen reportedly wondered about a shoal of porpoises. The witnesses answered that the humps did not ripple, but rose and sank together. In 2019, Robert L. France offered a new reading. Perhaps the humps were floats or debris trailing from a basking shark tangled in fishing gear; if so, the ministers recorded one of the earliest European descriptions of a shark surviving entanglement.

The case travelled through later books, beginning when F. Buckland reproduced Twopeny's sketch in 1882. A. C. Oudemans gave it two figures in The Great Sea-Serpent in 1892. R.T. Gould retold it in 1934 with Bogle's drawings, and Bernard Heuvelmans cited it in In the Wake of the Sea-Serpents. Loch Hourn kept its reputation. In the 1950s Willie MacKenzie, then aged 9, reported a head "ten feet out of the water".