Caldwell Harpur – diaries of a crank

Blog by Stacey Seddon, Historic Environment Assistant

31 July 2026

Earlier this year, I made the ten-hour train journey from County Durham to Penzance to visit a unique archive collection at the Morrab Library created by the brilliant and eccentric Nenthead assayer, Caldwell Harpur.

Caldwell lived in Nenthead for 20 years, leaving behind volumes of personal diaries encrypted in his self-invented alphabet. A lifelong vegetarian, an animal lover, a science fiction author, an avid book collector, and a dabbler in mysticism, he was Nenthead’s most eccentric Edwardian. Caldwell also wrote compulsively, corresponding with everyone from close family to Russian radicals, spiritualist mediums, and science fiction author, H.G. Wells.

The journey I was making was the same one that Caldwell had made 105 years ago. After 22 years working as an assayer for the Ville Montaigne Company in Nenthead, Caldwell was forced to leave due to the closure of the mines. He moved to Penzance hoping to find work in the Cornish metal mines. There, unsurprisingly for a compulsive book collector, he immediately became a member of the Morrab Library.

Cornwall’s only independent library, the Morrab was established in 1818. It is surrounded by subtropical gardens and one of the few existing photographs of Caldwell is in the Morrab Gardens petting a cat.

When I arrived, I was greeted by Lisa Di-Tommasso, the incredibly helpful librarian, who wheeled out an overflowing trolley containing 16 boxes of Caldwell’s material. I was led up a series of winding stairs to a cosy, book-lined room with sea views and sat down to unwrap the carefully packed parcels of his life’s work.

Writings

All of Caldwell’s diaries and writings are extensively indexed by subject and date, giving us a glimpse into how his brain worked. Caldwell was a highly original thinker and a prolific writer and chronicler. He wrote a two to 300 word daily diary entry every day for 62 years. For over 50 years, he encrypted these diaries using a self-invented alphabet he called “Lenish”.

Caldwell’s archive at the Morrab includes:

• 16 boxes full of diaries (written in Lenish)
• A manuscript autobiography titled “Life of a Crank”
• Hundreds of intimately detailed letters to his brother Reginald
• Meticulous records of his daily life and library collections, groceries, household objects, rain fall, expenditure etc

Caldwell also wrote:

• Hundreds of newspaper articles and letters
• Fiction (science fiction, historical fiction, children’s stories)
• Treatises on animism, sexual liberation, vegetarianism, pacifism etc

Nenthead letters

The material I was interested in related to Caldwell’s 22 years in Nenthead, including hundreds of surviving letters that he wrote during this time. They were, helpfully, written in English and hold a rare first-person account of Nenthead during the decline of large-scale metalliferous mining in the area. Themes included:

• Radical politics in Nenthead – washerboy strikes, tensions between management and workers, secretly dropping socialist literature on the bosses’ desks
• Local gossip, scandals (including his own), and descriptions of the many unconventional visitors to his Nenthead home including anarchist sandal-makers, free love advocates, theosophists, and female mineralogists
• The impact of new technology on Nentheadians, for example, he mentions an Alston bank manager asking to charge his electric car off the mine’s dynamo. Also a lady cleaning the mine laboratory who “understands now how to switch off the electric light […] her first evening, two months ago she spent half an hour trying to blow it out.”

Sadly, many of the Nenthead letters were in a very fragile condition due to Caldwell’s damp living conditions and his habit of recycling paper. Most of his letters were written on femur tracing paper which was not designed to last over a century. The research trip allowed me to photograph these unique items and preserve them for future generations to discover.

The material digitised during this visit will be the basis of an exciting new volunteer project – Diaries of a Crank: decoding the secret diaries of a Nenthead assayer. If you would like to learn about Caldwell’s life, have a go at deciphering his code, and find out about the volunteer project to reveal the history in his letters and diaries, you can join an online session on Monday 10 August: or email me direct.

The research into Caldwell Harpur’s historical archive is part of the Land of Lead and Silver project which is led by the North Pennines National Landscape team and funded by The National Lottery Heritage Fund, with thanks to National Lottery players, and Historic England.