On this spot on a chilly winter’s night in 1845, while returning from an evening drinking in a local pub, William Thomson, who would later go on to become Lord Kelvin, one of the greatest scientists ever to study at Glasgow University, tripped and fell into the river below. In doing so, he instantly became the coldest thing in the entire universe, and thus the concept of Absolute Zero was born.
As he pulled himself out of the water, Thomson realised he needed to create an entirely new way of measuring temperature to describe just how cold he felt after his unfortunate immersion. He named this the Kelvin Scale in honour of the river which had inspired what turned out to be the most important discovery of his illustrious career.
This plaque was erected in 2025 by the Lord Kelvin Appreciation Society to mark the 180th anniversary of this fortuitous event.