George Sinclair (c. 1630–1696) was a versatile Scottish academic, mathematician, and engineer whose career bridged the gap between early modern science and traditional belief systems. He is historically distinguished as the first Professor of Mathematics at the University of Glasgow, a position that reflected his standing in the academic community of seventeenth-century Scotland. Throughout his life, Sinclair engaged in a wide variety of intellectual pursuits, ranging from practical engineering projects to the study of the supernatural.\n\nIn the realm of science and engineering, Sinclair was a pioneer in the study of hydrostatics and geology. His practical observations, particularly those gathered through his hands-on experience working in Scottish coal mines, led to some of the earliest systematic studies of geological structures. In 1672, he published a comprehensive volume on hydrostatics that combined his scientific theories with practical observations, demonstrating a keen interest in the physical mechanics of the natural world.\n\nDespite his scientific credentials, Sinclair is also widely remembered as a demonologist. His most famous work, Satan's Invisible World Discovered, published around 1685, compiled numerous accounts of witchcraft, apparitions, and other supernatural occurrences. He frequently blended his scientific and supernatural interests; for instance, his 1672 hydrostatics book famously included an account of the "Glenluce Devil," a poltergeist case from the mid-1650s. Through these writings, Sinclair sought to document and analyze the unseen world with the same curiosity he applied to physical engineering.
