The Castle, the Mathematician,
and the Long-Lost Notebook:
Craigievar’s Hidden Legacy
Discovering Craigievar Castle’s Hidden Mathematical Treasure
Nestled in the scenic Aberdeenshire countryside, Craigievar Castle has long been a symbol of Scottish heritage and the legacy of Clan Sempill. Yet, this enchanting pink castle holds more than architectural beauty—it was once the unlikely home of a long-lost manuscript by Colin MacLaurin, one of Scotland’s most celebrated mathematicians. After centuries of mystery and intrigue, this remarkable notebook has found its way back to its rightful place at the University of Glasgow. David Horowitz explores the incredible journey of this historic artifact and its connection to Craigievar Castle, where history, mathematics, and discovery converge.
Besides having been the seat of Clan Sempill for over 350 years, Craigievar Castle was also the brief home of a missing student notebook handwritten by one of Scotland’s most renowned mathematicians. Colin MacLaurin (1698–1746) matriculated at the University of Glasgow in 1709 at the age of eleven. While extraordinary by today’s standards, this was common for young boys at the beginning of the eighteenth century. During his time at the university, MacLaurin kept a small student notebook in which is penned regent’s lectures, personal essays, and some very advanced Newtonian mathematics. After MacLaurin’s death in 1746, the notebook passed to his protégée Sir Andrew Mitchell (1708–1771), who would later become the British envoy to the court of King Frederick the Great of Prussia.
When Mitchell died in 1771, the notebook was inherited along with his “plate furniture jewels books papers &c” by Sir Andrew Forbes (1709–1773), the 4th Baronet of Craigievar. Forbes brought the notebook to Fintray House in Aberdeenshire, where it remained until the house was demolished in 1952. From there, it was transferred to Craigievar Castle, where it became part of the library of William Sempill-Forbes (1893–1963), the 10th Baronet of Craigievar and 19th Lord Sempill, and his second wife, Cecilia Alice née Dunbar-Kilburn (1903–1984).
The Honourable Mrs. Ann Forbes-Sempill and her daughter Anne Moira, as painted by John Lavery - Ulster Museum, Public Domain
In 1974, the remaining Mitchell papers at Craigievar Castle were sold to the British Museum. However, the MacLaurin Student Notebook did not appear on the inventory. That is because sometime around 1963, Lady Forbes-Sempill had loaned it to Patrick Francis Doran (1929–2012) of St. Mary’s College in Twickenham, and it was never returned. Doran used the notebook in connection with his Ph.D. research on Andrew Mitchell. In the early-1970s, Doran briefly loaned the notebook to Professor Eric Gray Forbes (1933–1984) of the University of Edinburgh, but by 1974 it had been returned to Doran, who had moved to Castleconnell (Ireland), having been appointed to the faculty at the National Institute of Higher Education (later the University of Limerick). Mathematical historians and archivists speculated about its existence and location for decades. It remained missing until December 2022, when it was located by Doran’s son, Hans Dermott Doran (after being tracked down by this author). In June 2023, Lady Forbes-Sempill’s youngest daughter, Brigid Gabriel, gifted the MacLaurin Student Notebook to the University of Glasgow Library Archives and Special Collections (GB 247 ASC 010), where it now resides.
Colin MacLaurin wrote his notebook during 1710–1712 while he was a master’s student at Glasgow. It measures only 153 x 100 mm and has 172 surviving folios. The notebook is written from both ends and meets between folios 66 & 67. It is written in black ink in English, Latin, and Greek with numerous diagrams. Aside from MacLaurin’s mathematics, it also contains an essay about Adam, a rhyming poem of ten stanzas praising God and His creations, and a discourse on infinity. On its pages, one can see early examples of Newtonian mathematical notation.
The University of Glasgow Library is in the process of digitizing the notebook so that it will soon be available online. In the meantime, you can contact the library for further information. Indeed, the MacLaurin Student Notebook has finally returned to the University of Glasgow after its three-century circuitous journey.
David Horowitz, Professor Emeritus
Golden West College
Huntington Beach, CA 92647
[email protected]
With thanks to John Lemon, property manager of Craigievar Castle.